drivers/nfc/trf7970a.c

   1 /*
   2  * TI TRF7970a RFID/NFC Transceiver Driver
   3  *
   4  * Copyright (C) 2013 Texas Instruments Incorporated - http://www.ti.com
   5  *
   6  * Author: Erick Macias <emacias@ti.com>
   7  * Author: Felipe Balbi <balbi@ti.com>
   8  * Author: Mark A. Greer <mgreer@animalcreek.com>
   9  *
  10  * This program is free software: you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License version 2  of
  12  * the License as published by the Free Software Foundation.
  13  */
  14
  15 #include <linux/module.h>
  16 #include <linux/device.h>
  17 #include <linux/netdevice.h>
  18 #include <linux/interrupt.h>
  19 #include <linux/pm_runtime.h>
  20 #include <linux/nfc.h>
  21 #include <linux/skbuff.h>
  22 #include <linux/delay.h>
  23 #include <linux/gpio.h>
  24 #include <linux/of.h>
  25 #include <linux/of_gpio.h>
  26 #include <linux/spi/spi.h>
  27 #include <linux/regulator/consumer.h>
  28
  29 #include <net/nfc/nfc.h>
  30 #include <net/nfc/digital.h>
  31
  32 /* There are 3 ways the host can communicate with the trf7970a:
  33  * parallel mode, SPI with Slave Select (SS) mode, and SPI without
  34  * SS mode.  The driver only supports the two SPI modes.
  35  *
  36  * The trf7970a is very timing sensitive and the VIN, EN2, and EN
  37  * pins must asserted in that order and with specific delays in between.
  38  * The delays used in the driver were provided by TI and have been
  39  * confirmed to work with this driver.
  40  *
  41  * Timeouts are implemented using the delayed workqueue kernel facility.
  42  * Timeouts are required so things don't hang when there is no response
  43  * from the trf7970a (or tag).  Using this mechanism creates a race with
  44  * interrupts, however.  That is, an interrupt and a timeout could occur
  45  * closely enough together that one is blocked by the mutex while the other
  46  * executes.  When the timeout handler executes first and blocks the
  47  * interrupt handler, it will eventually set the state to IDLE so the
  48  * interrupt handler will check the state and exit with no harm done.
  49  * When the interrupt handler executes first and blocks the timeout handler,
  50  * the cancel_delayed_work() call will know that it didn't cancel the
  51  * work item (i.e., timeout) and will return zero.  That return code is
  52  * used by the timer handler to indicate that it should ignore the timeout
  53  * once its unblocked.
  54  *
  55  * Aborting an active command isn't as simple as it seems because the only
  56  * way to abort a command that's already been sent to the tag is so turn
  57  * off power to the tag.  If we do that, though, we'd have to go through
  58  * the entire anticollision procedure again but the digital layer doesn't
  59  * support that.  So, if an abort is received before trf7970a_in_send_cmd()
  60  * has sent the command to the tag, it simply returns -ECANCELED.  If the
  61  * command has already been sent to the tag, then the driver continues
  62  * normally and recieves the response data (or error) but just before
  63  * sending the data upstream, it frees the rx_skb and sends -ECANCELED
  64  * upstream instead.  If the command failed, that error will be sent
  65  * upstream.
  66  *
  67  * When recieving data from a tag and the interrupt status register has
  68  * only the SRX bit set, it means that all of the data has been received
  69  * (once what's in the fifo has been read).  However, depending on timing
  70  * an interrupt status with only the SRX bit set may not be recived.  In
  71  * those cases, the timeout mechanism is used to wait 20 ms in case more
  72  * data arrives.  After 20 ms, it is assumed that all of the data has been
  73  * received and the accumulated rx data is sent upstream.  The
  74  * 'TRF7970A_ST_WAIT_FOR_RX_DATA_CONT' state is used for this purpose
  75  * (i.e., it indicates that some data has been received but we're not sure
  76  * if there is more coming so a timeout in this state means all data has
  77  * been received and there isn't an error).  The delay is 20 ms since delays
  78  * of ~16 ms have been observed during testing.
  79  *
  80  * Type 2 write and sector select commands respond with a 4-bit ACK or NACK.
  81  * Having only 4 bits in the FIFO won't normally generate an interrupt so
  82  * driver enables the '4_bit_RX' bit of the Special Functions register 1
  83  * to cause an interrupt in that case.  Leaving that bit for a read command
  84  * messes up the data returned so it is only enabled when the framing is
  85  * 'NFC_DIGITAL_FRAMING_NFCA_T2T' and the command is not a read command.
  86  * Unfortunately, that means that the driver has to peek into tx frames
  87  * when the framing is 'NFC_DIGITAL_FRAMING_NFCA_T2T'.  This is done by
  88  * the trf7970a_per_cmd_config() routine.
  89  *
  90  * ISO/IEC 15693 frames specify whether to use single or double sub-carrier
  91  * frequencies and whether to use low or high data rates in the flags byte
  92  * of the frame.  This means that the driver has to peek at all 15693 frames
  93  * to determine what speed to set the communication to.  In addition, write
  94  * and lock commands use the OPTION flag to indicate that an EOF must be
  95  * sent to the tag before it will send its response.  So the driver has to
  96  * examine all frames for that reason too.
  97  *
  98  * It is unclear how long to wait before sending the EOF.  According to the
  99  * Note under Table 1-1 in section 1.6 of
 100  * http://www.ti.com/lit/ug/scbu011/scbu011.pdf, that wait should be at least
 101  * 10 ms for TI Tag-it HF-I tags; however testing has shown that is not long
 102  * enough.  For this reason, the driver waits 20 ms which seems to work
 103  * reliably.
 104  */
 105
 106 #define TRF7970A_SUPPORTED_PROTOCOLS \
 107                 (NFC_PROTO_MIFARE_MASK | NFC_PROTO_ISO14443_MASK |      \
 108                  NFC_PROTO_ISO14443_B_MASK | NFC_PROTO_ISO15693_MASK)
 109
 110 #define TRF7970A_AUTOSUSPEND_DELAY              30000 /* 30 seconds */
 111
 112 /* TX data must be prefixed with a FIFO reset cmd, a cmd that depends
 113  * on what the current framing is, the address of the TX length byte 1
 114  * register (0x1d), and the 2 byte length of the data to be transmitted.
 115  * That totals 5 bytes.
 116  */
 117 #define TRF7970A_TX_SKB_HEADROOM                5
 118
 119 #define TRF7970A_RX_SKB_ALLOC_SIZE              256
 120
 121 #define TRF7970A_FIFO_SIZE                      128
 122
 123 /* TX length is 3 nibbles long ==> 4KB - 1 bytes max */
 124 #define TRF7970A_TX_MAX                         (4096 - 1)
 125
 126 #define TRF7970A_WAIT_FOR_RX_DATA_TIMEOUT       20
 127 #define TRF7970A_WAIT_FOR_FIFO_DRAIN_TIMEOUT    3
 128 #define TRF7970A_WAIT_TO_ISSUE_ISO15693_EOF     20
 129
 130 /* Quirks */
 131 /* Erratum: When reading IRQ Status register on trf7970a, we must issue a
 132  * read continuous command for IRQ Status and Collision Position registers.
 133  */
 134 #define TRF7970A_QUIRK_IRQ_STATUS_READ_ERRATA   BIT(0)
 135
 136 /* Direct commands */
 137 #define TRF7970A_CMD_IDLE                       0x00
 138 #define TRF7970A_CMD_SOFT_INIT                  0x03
 139 #define TRF7970A_CMD_RF_COLLISION               0x04
 140 #define TRF7970A_CMD_RF_COLLISION_RESPONSE_N    0x05
 141 #define TRF7970A_CMD_RF_COLLISION_RESPONSE_0    0x06
 142 #define TRF7970A_CMD_FIFO_RESET                 0x0f
 143 #define TRF7970A_CMD_TRANSMIT_NO_CRC            0x10
 144 #define TRF7970A_CMD_TRANSMIT                   0x11
 145 #define TRF7970A_CMD_DELAY_TRANSMIT_NO_CRC      0x12
 146 #define TRF7970A_CMD_DELAY_TRANSMIT             0x13
 147 #define TRF7970A_CMD_EOF                        0x14
 148 #define TRF7970A_CMD_CLOSE_SLOT                 0x15
 149 #define TRF7970A_CMD_BLOCK_RX                   0x16
 150 #define TRF7970A_CMD_ENABLE_RX                  0x17
 151 #define TRF7970A_CMD_TEST_EXT_RF                0x18
 152 #define TRF7970A_CMD_TEST_INT_RF                0x19
 153 #define TRF7970A_CMD_RX_GAIN_ADJUST             0x1a
 154
 155 /* Bits determining whether its a direct command or register R/W,
 156  * whether to use a continuous SPI transaction or not, and the actual
 157  * direct cmd opcode or regster address.
 158  */
 159 #define TRF7970A_CMD_BIT_CTRL                   BIT(7)
 160 #define TRF7970A_CMD_BIT_RW                     BIT(6)
 161 #define TRF7970A_CMD_BIT_CONTINUOUS             BIT(5)
 162 #define TRF7970A_CMD_BIT_OPCODE(opcode)         ((opcode) & 0x1f)
 163
 164 /* Registers addresses */
 165 #define TRF7970A_CHIP_STATUS_CTRL               0x00
 166 #define TRF7970A_ISO_CTRL                       0x01
 167 #define TRF7970A_ISO14443B_TX_OPTIONS           0x02
 168 #define TRF7970A_ISO14443A_HIGH_BITRATE_OPTIONS 0x03
 169 #define TRF7970A_TX_TIMER_SETTING_H_BYTE        0x04
 170 #define TRF7970A_TX_TIMER_SETTING_L_BYTE        0x05
 171 #define TRF7970A_TX_PULSE_LENGTH_CTRL           0x06
 172 #define TRF7970A_RX_NO_RESPONSE_WAIT            0x07
 173 #define TRF7970A_RX_WAIT_TIME                   0x08
 174 #define TRF7970A_MODULATOR_SYS_CLK_CTRL         0x09
 175 #define TRF7970A_RX_SPECIAL_SETTINGS            0x0a
 176 #define TRF7970A_REG_IO_CTRL                    0x0b
 177 #define TRF7970A_IRQ_STATUS                     0x0c
 178 #define TRF7970A_COLLISION_IRQ_MASK             0x0d
 179 #define TRF7970A_COLLISION_POSITION             0x0e
 180 #define TRF7970A_RSSI_OSC_STATUS                0x0f
 181 #define TRF7970A_SPECIAL_FCN_REG1               0x10
 182 #define TRF7970A_SPECIAL_FCN_REG2               0x11
 183 #define TRF7970A_RAM1                           0x12
 184 #define TRF7970A_RAM2                           0x13
 185 #define TRF7970A_ADJUTABLE_FIFO_IRQ_LEVELS      0x14
 186 #define TRF7970A_NFC_LOW_FIELD_LEVEL            0x16
 187 #define TRF7970A_NFCID1                         0x17
 188 #define TRF7970A_NFC_TARGET_LEVEL               0x18
 189 #define TRF79070A_NFC_TARGET_PROTOCOL           0x19
 190 #define TRF7970A_TEST_REGISTER1                 0x1a
 191 #define TRF7970A_TEST_REGISTER2                 0x1b
 192 #define TRF7970A_FIFO_STATUS                    0x1c
 193 #define TRF7970A_TX_LENGTH_BYTE1                0x1d
 194 #define TRF7970A_TX_LENGTH_BYTE2                0x1e
 195 #define TRF7970A_FIFO_IO_REGISTER               0x1f
 196
 197 /* Chip Status Control Register Bits */
 198 #define TRF7970A_CHIP_STATUS_VRS5_3             BIT(0)
 199 #define TRF7970A_CHIP_STATUS_REC_ON             BIT(1)
 200 #define TRF7970A_CHIP_STATUS_AGC_ON             BIT(2)
 201 #define TRF7970A_CHIP_STATUS_PM_ON              BIT(3)
 202 #define TRF7970A_CHIP_STATUS_RF_PWR             BIT(4)
 203 #define TRF7970A_CHIP_STATUS_RF_ON              BIT(5)
 204 #define TRF7970A_CHIP_STATUS_DIRECT             BIT(6)
 205 #define TRF7970A_CHIP_STATUS_STBY               BIT(7)
 206
 207 /* ISO Control Register Bits */
 208 #define TRF7970A_ISO_CTRL_15693_SGL_1OF4_662    0x00
 209 #define TRF7970A_ISO_CTRL_15693_SGL_1OF256_662  0x01
 210 #define TRF7970A_ISO_CTRL_15693_SGL_1OF4_2648   0x02
 211 #define TRF7970A_ISO_CTRL_15693_SGL_1OF256_2648 0x03
 212 #define TRF7970A_ISO_CTRL_15693_DBL_1OF4_667a   0x04
 213 #define TRF7970A_ISO_CTRL_15693_DBL_1OF256_667  0x05
 214 #define TRF7970A_ISO_CTRL_15693_DBL_1OF4_2669   0x06
 215 #define TRF7970A_ISO_CTRL_15693_DBL_1OF256_2669 0x07
 216 #define TRF7970A_ISO_CTRL_14443A_106            0x08
 217 #define TRF7970A_ISO_CTRL_14443A_212            0x09
 218 #define TRF7970A_ISO_CTRL_14443A_424            0x0a
 219 #define TRF7970A_ISO_CTRL_14443A_848            0x0b
 220 #define TRF7970A_ISO_CTRL_14443B_106            0x0c
 221 #define TRF7970A_ISO_CTRL_14443B_212            0x0d
 222 #define TRF7970A_ISO_CTRL_14443B_424            0x0e
 223 #define TRF7970A_ISO_CTRL_14443B_848            0x0f
 224 #define TRF7970A_ISO_CTRL_FELICA_212            0x1a
 225 #define TRF7970A_ISO_CTRL_FELICA_424            0x1b
 226 #define TRF7970A_ISO_CTRL_RFID                  BIT(5)
 227 #define TRF7970A_ISO_CTRL_DIR_MODE              BIT(6)
 228 #define TRF7970A_ISO_CTRL_RX_CRC_N              BIT(7)  /* true == No CRC */
 229
 230 #define TRF7970A_ISO_CTRL_RFID_SPEED_MASK       0x1f
 231
 232 /* Modulator and SYS_CLK Control Register Bits */
 233 #define TRF7970A_MODULATOR_DEPTH(n)             ((n) & 0x7)
 234 #define TRF7970A_MODULATOR_DEPTH_ASK10          (TRF7970A_MODULATOR_DEPTH(0))
 235 #define TRF7970A_MODULATOR_DEPTH_OOK            (TRF7970A_MODULATOR_DEPTH(1))
 236 #define TRF7970A_MODULATOR_DEPTH_ASK7           (TRF7970A_MODULATOR_DEPTH(2))
 237 #define TRF7970A_MODULATOR_DEPTH_ASK8_5         (TRF7970A_MODULATOR_DEPTH(3))
 238 #define TRF7970A_MODULATOR_DEPTH_ASK13          (TRF7970A_MODULATOR_DEPTH(4))
 239 #define TRF7970A_MODULATOR_DEPTH_ASK16          (TRF7970A_MODULATOR_DEPTH(5))
 240 #define TRF7970A_MODULATOR_DEPTH_ASK22          (TRF7970A_MODULATOR_DEPTH(6))
 241 #define TRF7970A_MODULATOR_DEPTH_ASK30          (TRF7970A_MODULATOR_DEPTH(7))
 242 #define TRF7970A_MODULATOR_EN_ANA               BIT(3)
 243 #define TRF7970A_MODULATOR_CLK(n)               (((n) & 0x3) << 4)
 244 #define TRF7970A_MODULATOR_CLK_DISABLED         (TRF7970A_MODULATOR_CLK(0))
 245 #define TRF7970A_MODULATOR_CLK_3_6              (TRF7970A_MODULATOR_CLK(1))
 246 #define TRF7970A_MODULATOR_CLK_6_13             (TRF7970A_MODULATOR_CLK(2))
 247 #define TRF7970A_MODULATOR_CLK_13_27            (TRF7970A_MODULATOR_CLK(3))
 248 #define TRF7970A_MODULATOR_EN_OOK               BIT(6)
 249 #define TRF7970A_MODULATOR_27MHZ                BIT(7)
 250
 251 /* IRQ Status Register Bits */
 252 #define TRF7970A_IRQ_STATUS_NORESP              BIT(0) /* ISO15693 only */
 253 #define TRF7970A_IRQ_STATUS_COL                 BIT(1)
 254 #define TRF7970A_IRQ_STATUS_FRAMING_EOF_ERROR   BIT(2)
 255 #define TRF7970A_IRQ_STATUS_PARITY_ERROR        BIT(3)
 256 #define TRF7970A_IRQ_STATUS_CRC_ERROR           BIT(4)
 257 #define TRF7970A_IRQ_STATUS_FIFO                BIT(5)
 258 #define TRF7970A_IRQ_STATUS_SRX                 BIT(6)
 259 #define TRF7970A_IRQ_STATUS_TX                  BIT(7)
 260
 261 #define TRF7970A_IRQ_STATUS_ERROR                               \
 262                 (TRF7970A_IRQ_STATUS_COL |                      \
 263                  TRF7970A_IRQ_STATUS_FRAMING_EOF_ERROR |        \
 264                  TRF7970A_IRQ_STATUS_PARITY_ERROR |             \
 265                  TRF7970A_IRQ_STATUS_CRC_ERROR)
 266
 267 #define TRF7970A_SPECIAL_FCN_REG1_COL_7_6               BIT(0)
 268 #define TRF7970A_SPECIAL_FCN_REG1_14_ANTICOLL           BIT(1)
 269 #define TRF7970A_SPECIAL_FCN_REG1_4_BIT_RX              BIT(2)
 270 #define TRF7970A_SPECIAL_FCN_REG1_SP_DIR_MODE           BIT(3)
 271 #define TRF7970A_SPECIAL_FCN_REG1_NEXT_SLOT_37US        BIT(4)
 272 #define TRF7970A_SPECIAL_FCN_REG1_PAR43                 BIT(5)
 273
 274 #define TRF7970A_ADJUTABLE_FIFO_IRQ_LEVELS_WLH_124      (0x0 << 2)
 275 #define TRF7970A_ADJUTABLE_FIFO_IRQ_LEVELS_WLH_120      (0x1 << 2)
 276 #define TRF7970A_ADJUTABLE_FIFO_IRQ_LEVELS_WLH_112      (0x2 << 2)
 277 #define TRF7970A_ADJUTABLE_FIFO_IRQ_LEVELS_WLH_96       (0x3 << 2)
 278 #define TRF7970A_ADJUTABLE_FIFO_IRQ_LEVELS_WLL_4        0x0
 279 #define TRF7970A_ADJUTABLE_FIFO_IRQ_LEVELS_WLL_8        0x1
 280 #define TRF7970A_ADJUTABLE_FIFO_IRQ_LEVELS_WLL_16       0x2
 281 #define TRF7970A_ADJUTABLE_FIFO_IRQ_LEVELS_WLL_32       0x3
 282
 283 #define TRF7970A_FIFO_STATUS_OVERFLOW           BIT(7)
 284
 285 /* NFC (ISO/IEC 14443A) Type 2 Tag commands */
 286 #define NFC_T2T_CMD_READ                        0x30
 287
 288 /* ISO 15693 commands codes */
 289 #define ISO15693_CMD_INVENTORY                  0x01
 290 #define ISO15693_CMD_READ_SINGLE_BLOCK          0x20
 291 #define ISO15693_CMD_WRITE_SINGLE_BLOCK         0x21
 292 #define ISO15693_CMD_LOCK_BLOCK                 0x22
 293 #define ISO15693_CMD_READ_MULTIPLE_BLOCK        0x23
 294 #define ISO15693_CMD_WRITE_MULTIPLE_BLOCK       0x24
 295 #define ISO15693_CMD_SELECT                     0x25
 296 #define ISO15693_CMD_RESET_TO_READY             0x26
 297 #define ISO15693_CMD_WRITE_AFI                  0x27
 298 #define ISO15693_CMD_LOCK_AFI                   0x28
 299 #define ISO15693_CMD_WRITE_DSFID                0x29
 300 #define ISO15693_CMD_LOCK_DSFID                 0x2a
 301 #define ISO15693_CMD_GET_SYSTEM_INFO            0x2b
 302 #define ISO15693_CMD_GET_MULTIPLE_BLOCK_SECURITY_STATUS 0x2c
 303
 304 /* ISO 15693 request and response flags */
 305 #define ISO15693_REQ_FLAG_SUB_CARRIER           BIT(0)
 306 #define ISO15693_REQ_FLAG_DATA_RATE             BIT(1)
 307 #define ISO15693_REQ_FLAG_INVENTORY             BIT(2)
 308 #define ISO15693_REQ_FLAG_PROTOCOL_EXT          BIT(3)
 309 #define ISO15693_REQ_FLAG_SELECT                BIT(4)
 310 #define ISO15693_REQ_FLAG_AFI                   BIT(4)
 311 #define ISO15693_REQ_FLAG_ADDRESS               BIT(5)
 312 #define ISO15693_REQ_FLAG_NB_SLOTS              BIT(5)
 313 #define ISO15693_REQ_FLAG_OPTION                BIT(6)
 314
 315 #define ISO15693_REQ_FLAG_SPEED_MASK \
 316                 (ISO15693_REQ_FLAG_SUB_CARRIER | ISO15693_REQ_FLAG_DATA_RATE)
 317
 318 enum trf7970a_state {
 319         TRF7970A_ST_OFF,
 320         TRF7970A_ST_IDLE,
 321         TRF7970A_ST_IDLE_RX_BLOCKED,
 322         TRF7970A_ST_WAIT_FOR_TX_FIFO,
 323         TRF7970A_ST_WAIT_FOR_RX_DATA,
 324         TRF7970A_ST_WAIT_FOR_RX_DATA_CONT,
 325         TRF7970A_ST_WAIT_TO_ISSUE_EOF,
 326         TRF7970A_ST_MAX
 327 };
 328
 329 struct trf7970a {
 330         enum trf7970a_state             state;
 331         struct device                   *dev;
 332         struct spi_device               *spi;
 333         struct regulator                *regulator;
 334         struct nfc_digital_dev          *ddev;
 335         u32                             quirks;
 336         bool                            aborting;
 337         struct sk_buff                  *tx_skb;
 338         struct sk_buff                  *rx_skb;
 339         nfc_digital_cmd_complete_t      cb;
 340         void                            *cb_arg;
 341         u8                              chip_status_ctrl;
 342         u8                              iso_ctrl;
 343         u8                              iso_ctrl_tech;
 344         u8                              modulator_sys_clk_ctrl;
 345         u8                              special_fcn_reg1;
 346         int                             technology;
 347         int                             framing;
 348         u8                              tx_cmd;
 349         bool                            issue_eof;
 350         int                             en2_gpio;
 351         int                             en_gpio;
 352         struct mutex                    lock;
 353         unsigned int                    timeout;
 354         bool                            ignore_timeout;
 355         struct delayed_work             timeout_work;
 356 };
 357
 358
 359 static int trf7970a_cmd(struct trf7970a *trf, u8 opcode)
 360 {
 361         u8 cmd = TRF7970A_CMD_BIT_CTRL | TRF7970A_CMD_BIT_OPCODE(opcode);
 362         int ret;
 363
 364         dev_dbg(trf->dev, "cmd: 0x%x\n", cmd);
 365
 366         ret = spi_write(trf->spi, &cmd, 1);
 367         if (ret)
 368                 dev_err(trf->dev, "%s - cmd: 0x%x, ret: %d\n", __func__, cmd,
 369                                 ret);
 370         return ret;
 371 }
 372
 373 static int trf7970a_read(struct trf7970a *trf, u8 reg, u8 *val)
 374 {
 375         u8 addr = TRF7970A_CMD_BIT_RW | reg;
 376         int ret;
 377
 378         ret = spi_write_then_read(trf->spi, &addr, 1, val, 1);
 379         if (ret)
 380                 dev_err(trf->dev, "%s - addr: 0x%x, ret: %d\n", __func__, addr,
 381                                 ret);
 382
 383         dev_dbg(trf->dev, "read(0x%x): 0x%x\n", addr, *val);
 384
 385         return ret;
 386 }
 387
 388 static int trf7970a_read_cont(struct trf7970a *trf, u8 reg,
 389                 u8 *buf, size_t len)
 390 {
 391         u8 addr = reg | TRF7970A_CMD_BIT_RW | TRF7970A_CMD_BIT_CONTINUOUS;
 392         int ret;
 393
 394         dev_dbg(trf->dev, "read_cont(0x%x, %zd)\n", addr, len);
 395
 396         ret = spi_write_then_read(trf->spi, &addr, 1, buf, len);
 397         if (ret)
 398                 dev_err(trf->dev, "%s - addr: 0x%x, ret: %d\n", __func__, addr,
 399                                 ret);
 400         return ret;
 401 }
 402
 403 static int trf7970a_write(struct trf7970a *trf, u8 reg, u8 val)
 404 {
 405         u8 buf[2] = { reg, val };
 406         int ret;
 407
 408         dev_dbg(trf->dev, "write(0x%x): 0x%x\n", reg, val);
 409
 410         ret = spi_write(trf->spi, buf, 2);
 411         if (ret)
 412                 dev_err(trf->dev, "%s - write: 0x%x 0x%x, ret: %d\n", __func__,
 413                                 buf[0], buf[1], ret);
 414
 415         return ret;
 416 }
 417
 418 static int trf7970a_read_irqstatus(struct trf7970a *trf, u8 *status)
 419 {
 420         int ret;
 421         u8 buf[2];
 422         u8 addr;
 423
 424         addr = TRF7970A_IRQ_STATUS | TRF7970A_CMD_BIT_RW;
 425
 426         if (trf->quirks & TRF7970A_QUIRK_IRQ_STATUS_READ_ERRATA) {
 427                 addr |= TRF7970A_CMD_BIT_CONTINUOUS;
 428                 ret = spi_write_then_read(trf->spi, &addr, 1, buf, 2);
 429         } else {
 430                 ret = spi_write_then_read(trf->spi, &addr, 1, buf, 1);
 431         }
 432
 433         if (ret)
 434                 dev_err(trf->dev, "%s - irqstatus: Status read failed: %d\n",
 435                                 __func__, ret);
 436         else
 437                 *status = buf[0];
 438
 439         return ret;
 440 }
 441
 442 static void trf7970a_send_upstream(struct trf7970a *trf)
 443 {
 444         u8 rssi;
 445
 446         dev_kfree_skb_any(trf->tx_skb);
 447         trf->tx_skb = NULL;
 448
 449         if (trf->rx_skb && !IS_ERR(trf->rx_skb) && !trf->aborting)
 450                 print_hex_dump_debug("trf7970a rx data: ", DUMP_PREFIX_NONE,
 451                                 16, 1, trf->rx_skb->data, trf->rx_skb->len,
 452                                 false);
 453
 454         /* According to the manual it is "good form" to reset the fifo and
 455          * read the RSSI levels & oscillator status register here.  It doesn't
 456          * explain why.
 457          */
 458         trf7970a_cmd(trf, TRF7970A_CMD_FIFO_RESET);
 459         trf7970a_read(trf, TRF7970A_RSSI_OSC_STATUS, &rssi);
 460
 461         trf->state = TRF7970A_ST_IDLE;
 462
 463         if (trf->aborting) {
 464                 dev_dbg(trf->dev, "Abort process complete\n");
 465
 466                 if (!IS_ERR(trf->rx_skb)) {
 467                         kfree_skb(trf->rx_skb);
 468                         trf->rx_skb = ERR_PTR(-ECANCELED);
 469                 }
 470
 471                 trf->aborting = false;
 472         }
 473
 474         trf->cb(trf->ddev, trf->cb_arg, trf->rx_skb);
 475
 476         trf->rx_skb = NULL;
 477 }
 478
 479 static void trf7970a_send_err_upstream(struct trf7970a *trf, int errno)
 480 {
 481         dev_dbg(trf->dev, "Error - state: %d, errno: %d\n", trf->state, errno);
 482
 483         kfree_skb(trf->rx_skb);
 484         trf->rx_skb = ERR_PTR(errno);
 485
 486         trf7970a_send_upstream(trf);
 487 }
 488
 489 static int trf7970a_transmit(struct trf7970a *trf, struct sk_buff *skb,
 490                 unsigned int len)
 491 {
 492         unsigned int timeout;
 493         int ret;
 494
 495         print_hex_dump_debug("trf7970a tx data: ", DUMP_PREFIX_NONE,
 496                         16, 1, skb->data, len, false);
 497
 498         ret = spi_write(trf->spi, skb->data, len);
 499         if (ret) {
 500                 dev_err(trf->dev, "%s - Can't send tx data: %d\n", __func__,
 501                                 ret);
 502                 return ret;
 503         }
 504
 505         skb_pull(skb, len);
 506
 507         if (skb->len > 0) {
 508                 trf->state = TRF7970A_ST_WAIT_FOR_TX_FIFO;
 509                 timeout = TRF7970A_WAIT_FOR_FIFO_DRAIN_TIMEOUT;
 510         } else {
 511                 if (trf->issue_eof) {
 512                         trf->state = TRF7970A_ST_WAIT_TO_ISSUE_EOF;
 513                         timeout = TRF7970A_WAIT_TO_ISSUE_ISO15693_EOF;
 514                 } else {
 515                         trf->state = TRF7970A_ST_WAIT_FOR_RX_DATA;
 516                         timeout = trf->timeout;
 517                 }
 518         }
 519
 520         dev_dbg(trf->dev, "Setting timeout for %d ms, state: %d\n", timeout,
 521                         trf->state);
 522
 523         schedule_delayed_work(&trf->timeout_work, msecs_to_jiffies(timeout));
 524
 525         return 0;
 526 }
 527
 528 static void trf7970a_fill_fifo(struct trf7970a *trf)
 529 {
 530         struct sk_buff *skb = trf->tx_skb;
 531         unsigned int len;
 532         int ret;
 533         u8 fifo_bytes;
 534
 535         ret = trf7970a_read(trf, TRF7970A_FIFO_STATUS, &fifo_bytes);
 536         if (ret) {
 537                 trf7970a_send_err_upstream(trf, ret);
 538                 return;
 539         }
 540
 541         dev_dbg(trf->dev, "Filling FIFO - fifo_bytes: 0x%x\n", fifo_bytes);
 542
 543         if (fifo_bytes & TRF7970A_FIFO_STATUS_OVERFLOW) {
 544                 dev_err(trf->dev, "%s - fifo overflow: 0x%x\n", __func__,
 545                                 fifo_bytes);
 546                 trf7970a_send_err_upstream(trf, -EIO);
 547                 return;
 548         }
 549
 550         /* Calculate how much more data can be written to the fifo */
 551         len = TRF7970A_FIFO_SIZE - fifo_bytes;
 552         len = min(skb->len, len);
 553
 554         ret = trf7970a_transmit(trf, skb, len);
 555         if (ret)
 556                 trf7970a_send_err_upstream(trf, ret);
 557 }
 558
 559 static void trf7970a_drain_fifo(struct trf7970a *trf, u8 status)
 560 {
 561         struct sk_buff *skb = trf->rx_skb;
 562         int ret;
 563         u8 fifo_bytes;
 564
 565         if (status & TRF7970A_IRQ_STATUS_ERROR) {
 566                 trf7970a_send_err_upstream(trf, -EIO);
 567                 return;
 568         }
 569
 570         ret = trf7970a_read(trf, TRF7970A_FIFO_STATUS, &fifo_bytes);
 571         if (ret) {
 572                 trf7970a_send_err_upstream(trf, ret);
 573                 return;
 574         }
 575
 576         dev_dbg(trf->dev, "Draining FIFO - fifo_bytes: 0x%x\n", fifo_bytes);
 577
 578         if (!fifo_bytes)
 579                 goto no_rx_data;
 580
 581         if (fifo_bytes & TRF7970A_FIFO_STATUS_OVERFLOW) {
 582                 dev_err(trf->dev, "%s - fifo overflow: 0x%x\n", __func__,
 583                                 fifo_bytes);
 584                 trf7970a_send_err_upstream(trf, -EIO);
 585                 return;
 586         }
 587
 588         if (fifo_bytes > skb_tailroom(skb)) {
 589                 skb = skb_copy_expand(skb, skb_headroom(skb),
 590                                 max_t(int, fifo_bytes,
 591                                         TRF7970A_RX_SKB_ALLOC_SIZE),
 592                                 GFP_KERNEL);
 593                 if (!skb) {
 594                         trf7970a_send_err_upstream(trf, -ENOMEM);
 595                         return;
 596                 }
 597
 598                 kfree_skb(trf->rx_skb);
 599                 trf->rx_skb = skb;
 600         }
 601
 602         ret = trf7970a_read_cont(trf, TRF7970A_FIFO_IO_REGISTER,
 603                         skb_put(skb, fifo_bytes), fifo_bytes);
 604         if (ret) {
 605                 trf7970a_send_err_upstream(trf, ret);
 606                 return;
 607         }
 608
 609         /* If received Type 2 ACK/NACK, shift right 4 bits and pass up */
 610         if ((trf->framing == NFC_DIGITAL_FRAMING_NFCA_T2T) && (skb->len == 1) &&
 611                         (trf->special_fcn_reg1 ==
 612                                  TRF7970A_SPECIAL_FCN_REG1_4_BIT_RX)) {
 613                 skb->data[0] >>= 4;
 614                 status = TRF7970A_IRQ_STATUS_SRX;
 615         } else {
 616                 trf->state = TRF7970A_ST_WAIT_FOR_RX_DATA_CONT;
 617         }
 618
 619 no_rx_data:
 620         if (status == TRF7970A_IRQ_STATUS_SRX) { /* Receive complete */
 621                 trf7970a_send_upstream(trf);
 622                 return;
 623         }
 624
 625         dev_dbg(trf->dev, "Setting timeout for %d ms\n",
 626                         TRF7970A_WAIT_FOR_RX_DATA_TIMEOUT);
 627
 628         schedule_delayed_work(&trf->timeout_work,
 629                         msecs_to_jiffies(TRF7970A_WAIT_FOR_RX_DATA_TIMEOUT));
 630 }
 631
 632 static irqreturn_t trf7970a_irq(int irq, void *dev_id)
 633 {
 634         struct trf7970a *trf = dev_id;
 635         int ret;
 636         u8 status;
 637
 638         mutex_lock(&trf->lock);
 639
 640         if (trf->state == TRF7970A_ST_OFF) {
 641                 mutex_unlock(&trf->lock);
 642                 return IRQ_NONE;
 643         }
 644
 645         ret = trf7970a_read_irqstatus(trf, &status);
 646         if (ret) {
 647                 mutex_unlock(&trf->lock);
 648                 return IRQ_NONE;
 649         }
 650
 651         dev_dbg(trf->dev, "IRQ - state: %d, status: 0x%x\n", trf->state,
 652                         status);
 653
 654         if (!status) {
 655                 mutex_unlock(&trf->lock);
 656                 return IRQ_NONE;
 657         }
 658
 659         switch (trf->state) {
 660         case TRF7970A_ST_IDLE:
 661         case TRF7970A_ST_IDLE_RX_BLOCKED:
 662                 /* If getting interrupts caused by RF noise, turn off the
 663                  * receiver to avoid unnecessary interrupts.  It will be
 664                  * turned back on in trf7970a_in_send_cmd() when the next
 665                  * command is issued.
 666                  */
 667                 if (status & TRF7970A_IRQ_STATUS_ERROR) {
 668                         trf7970a_cmd(trf, TRF7970A_CMD_BLOCK_RX);
 669                         trf->state = TRF7970A_ST_IDLE_RX_BLOCKED;
 670                 }
 671
 672                 trf7970a_cmd(trf, TRF7970A_CMD_FIFO_RESET);
 673                 break;
 674         case TRF7970A_ST_WAIT_FOR_TX_FIFO:
 675                 if (status & TRF7970A_IRQ_STATUS_TX) {
 676                         trf->ignore_timeout =
 677                                 !cancel_delayed_work(&trf->timeout_work);
 678                         trf7970a_fill_fifo(trf);
 679                 } else {
 680                         trf7970a_send_err_upstream(trf, -EIO);
 681                 }
 682                 break;
 683         case TRF7970A_ST_WAIT_FOR_RX_DATA:
 684         case TRF7970A_ST_WAIT_FOR_RX_DATA_CONT:
 685                 if (status & TRF7970A_IRQ_STATUS_SRX) {
 686                         trf->ignore_timeout =
 687                                 !cancel_delayed_work(&trf->timeout_work);
 688                         trf7970a_drain_fifo(trf, status);
 689                 } else if (status == TRF7970A_IRQ_STATUS_TX) {
 690                         trf7970a_cmd(trf, TRF7970A_CMD_FIFO_RESET);
 691                 } else {
 692                         trf7970a_send_err_upstream(trf, -EIO);
 693                 }
 694                 break;
 695         case TRF7970A_ST_WAIT_TO_ISSUE_EOF:
 696                 if (status != TRF7970A_IRQ_STATUS_TX)
 697                         trf7970a_send_err_upstream(trf, -EIO);
 698                 break;
 699         default:
 700                 dev_err(trf->dev, "%s - Driver in invalid state: %d\n",
 701                                 __func__, trf->state);
 702         }
 703
 704         mutex_unlock(&trf->lock);
 705         return IRQ_HANDLED;
 706 }
 707
 708 static void trf7970a_issue_eof(struct trf7970a *trf)
 709 {
 710         int ret;
 711
 712         dev_dbg(trf->dev, "Issuing EOF\n");
 713
 714         ret = trf7970a_cmd(trf, TRF7970A_CMD_FIFO_RESET);
 715         if (ret)
 716                 trf7970a_send_err_upstream(trf, ret);
 717
 718         ret = trf7970a_cmd(trf, TRF7970A_CMD_EOF);
 719         if (ret)
 720                 trf7970a_send_err_upstream(trf, ret);
 721
 722         trf->state = TRF7970A_ST_WAIT_FOR_RX_DATA;
 723
 724         dev_dbg(trf->dev, "Setting timeout for %d ms, state: %d\n",
 725                         trf->timeout, trf->state);
 726
 727         schedule_delayed_work(&trf->timeout_work,
 728                         msecs_to_jiffies(trf->timeout));
 729 }
 730
 731 static void trf7970a_timeout_work_handler(struct work_struct *work)
 732 {
 733         struct trf7970a *trf = container_of(work, struct trf7970a,
 734                         timeout_work.work);
 735
 736         dev_dbg(trf->dev, "Timeout - state: %d, ignore_timeout: %d\n",
 737                         trf->state, trf->ignore_timeout);
 738
 739         mutex_lock(&trf->lock);
 740
 741         if (trf->ignore_timeout)
 742                 trf->ignore_timeout = false;
 743         else if (trf->state == TRF7970A_ST_WAIT_FOR_RX_DATA_CONT)
 744                 trf7970a_send_upstream(trf); /* No more rx data so send up */
 745         else if (trf->state == TRF7970A_ST_WAIT_TO_ISSUE_EOF)
 746                 trf7970a_issue_eof(trf);
 747         else
 748                 trf7970a_send_err_upstream(trf, -ETIMEDOUT);
 749
 750         mutex_unlock(&trf->lock);
 751 }
 752
 753 static int trf7970a_init(struct trf7970a *trf)
 754 {
 755         int ret;
 756
 757         dev_dbg(trf->dev, "Initializing device - state: %d\n", trf->state);
 758
 759         ret = trf7970a_cmd(trf, TRF7970A_CMD_SOFT_INIT);
 760         if (ret)
 761                 goto err_out;
 762
 763         ret = trf7970a_cmd(trf, TRF7970A_CMD_IDLE);
 764         if (ret)
 765                 goto err_out;
 766
 767         /* Must clear NFC Target Detection Level reg due to erratum */
 768         ret = trf7970a_write(trf, TRF7970A_NFC_TARGET_LEVEL, 0);
 769         if (ret)
 770                 goto err_out;
 771
 772         ret = trf7970a_write(trf, TRF7970A_ADJUTABLE_FIFO_IRQ_LEVELS,
 773                         TRF7970A_ADJUTABLE_FIFO_IRQ_LEVELS_WLH_96 |
 774                         TRF7970A_ADJUTABLE_FIFO_IRQ_LEVELS_WLL_32);
 775         if (ret)
 776                 goto err_out;
 777
 778         ret = trf7970a_write(trf, TRF7970A_SPECIAL_FCN_REG1, 0);
 779         if (ret)
 780                 goto err_out;
 781
 782         trf->special_fcn_reg1 = 0;
 783
 784         trf->iso_ctrl = 0xff;
 785         return 0;
 786
 787 err_out:
 788         dev_dbg(trf->dev, "Couldn't init device: %d\n", ret);
 789         return ret;
 790 }
 791
 792 static void trf7970a_switch_rf_off(struct trf7970a *trf)
 793 {
 794         dev_dbg(trf->dev, "Switching rf off\n");
 795
 796         trf->chip_status_ctrl &= ~TRF7970A_CHIP_STATUS_RF_ON;
 797
 798         trf7970a_write(trf, TRF7970A_CHIP_STATUS_CTRL, trf->chip_status_ctrl);
 799
 800         trf->aborting = false;
 801         trf->state = TRF7970A_ST_OFF;
 802
 803         pm_runtime_mark_last_busy(trf->dev);
 804         pm_runtime_put_autosuspend(trf->dev);
 805 }
 806
 807 static void trf7970a_switch_rf_on(struct trf7970a *trf)
 808 {
 809         dev_dbg(trf->dev, "Switching rf on\n");
 810
 811         pm_runtime_get_sync(trf->dev);
 812
 813         trf->state = TRF7970A_ST_IDLE;
 814 }
 815
 816 static int trf7970a_switch_rf(struct nfc_digital_dev *ddev, bool on)
 817 {
 818         struct trf7970a *trf = nfc_digital_get_drvdata(ddev);
 819
 820         dev_dbg(trf->dev, "Switching RF - state: %d, on: %d\n", trf->state, on);
 821
 822         mutex_lock(&trf->lock);
 823
 824         if (on) {
 825                 switch (trf->state) {
 826                 case TRF7970A_ST_OFF:
 827                         trf7970a_switch_rf_on(trf);
 828                         break;
 829                 case TRF7970A_ST_IDLE:
 830                 case TRF7970A_ST_IDLE_RX_BLOCKED:
 831                         break;
 832                 default:
 833                         dev_err(trf->dev, "%s - Invalid request: %d %d\n",
 834                                         __func__, trf->state, on);
 835                         trf7970a_switch_rf_off(trf);
 836                 }
 837         } else {
 838                 switch (trf->state) {
 839                 case TRF7970A_ST_OFF:
 840                         break;
 841                 default:
 842                         dev_err(trf->dev, "%s - Invalid request: %d %d\n",
 843                                         __func__, trf->state, on);
 844                         /* FALLTHROUGH */
 845                 case TRF7970A_ST_IDLE:
 846                 case TRF7970A_ST_IDLE_RX_BLOCKED:
 847                         trf7970a_switch_rf_off(trf);
 848                 }
 849         }
 850
 851         mutex_unlock(&trf->lock);
 852         return 0;
 853 }
 854
 855 static int trf7970a_config_rf_tech(struct trf7970a *trf, int tech)
 856 {
 857         int ret = 0;
 858
 859         dev_dbg(trf->dev, "rf technology: %d\n", tech);
 860
 861         switch (tech) {
 862         case NFC_DIGITAL_RF_TECH_106A:
 863                 trf->iso_ctrl_tech = TRF7970A_ISO_CTRL_14443A_106;
 864                 trf->modulator_sys_clk_ctrl = TRF7970A_MODULATOR_DEPTH_OOK;
 865                 break;
 866         case NFC_DIGITAL_RF_TECH_106B:
 867                 trf->iso_ctrl_tech = TRF7970A_ISO_CTRL_14443B_106;
 868                 trf->modulator_sys_clk_ctrl = TRF7970A_MODULATOR_DEPTH_ASK10;
 869                 break;
 870         case NFC_DIGITAL_RF_TECH_ISO15693:
 871                 trf->iso_ctrl_tech = TRF7970A_ISO_CTRL_15693_SGL_1OF4_2648;
 872                 trf->modulator_sys_clk_ctrl = TRF7970A_MODULATOR_DEPTH_OOK;
 873                 break;
 874         default:
 875                 dev_dbg(trf->dev, "Unsupported rf technology: %d\n", tech);
 876                 return -EINVAL;
 877         }
 878
 879         trf->technology = tech;
 880
 881         return ret;
 882 }
 883
 884 static int trf7970a_config_framing(struct trf7970a *trf, int framing)
 885 {
 886         u8 iso_ctrl = trf->iso_ctrl_tech;
 887         int ret;
 888
 889         dev_dbg(trf->dev, "framing: %d\n", framing);
 890
 891         switch (framing) {
 892         case NFC_DIGITAL_FRAMING_NFCA_SHORT:
 893         case NFC_DIGITAL_FRAMING_NFCA_STANDARD:
 894                 trf->tx_cmd = TRF7970A_CMD_TRANSMIT_NO_CRC;
 895                 iso_ctrl |= TRF7970A_ISO_CTRL_RX_CRC_N;
 896                 break;
 897         case NFC_DIGITAL_FRAMING_NFCA_STANDARD_WITH_CRC_A:
 898         case NFC_DIGITAL_FRAMING_NFCA_T4T:
 899         case NFC_DIGITAL_FRAMING_NFCB:
 900         case NFC_DIGITAL_FRAMING_NFCB_T4T:
 901         case NFC_DIGITAL_FRAMING_ISO15693_INVENTORY:
 902         case NFC_DIGITAL_FRAMING_ISO15693_T5T:
 903                 trf->tx_cmd = TRF7970A_CMD_TRANSMIT;
 904                 iso_ctrl &= ~TRF7970A_ISO_CTRL_RX_CRC_N;
 905                 break;
 906         case NFC_DIGITAL_FRAMING_NFCA_T2T:
 907                 trf->tx_cmd = TRF7970A_CMD_TRANSMIT;
 908                 iso_ctrl |= TRF7970A_ISO_CTRL_RX_CRC_N;
 909                 break;
 910         default:
 911                 dev_dbg(trf->dev, "Unsupported Framing: %d\n", framing);
 912                 return -EINVAL;
 913         }
 914
 915         trf->framing = framing;
 916
 917         if (iso_ctrl != trf->iso_ctrl) {
 918                 ret = trf7970a_write(trf, TRF7970A_ISO_CTRL, iso_ctrl);
 919                 if (ret)
 920                         return ret;
 921
 922                 trf->iso_ctrl = iso_ctrl;
 923
 924                 ret = trf7970a_write(trf, TRF7970A_MODULATOR_SYS_CLK_CTRL,
 925                                 trf->modulator_sys_clk_ctrl);
 926                 if (ret)
 927                         return ret;
 928         }
 929
 930         if (!(trf->chip_status_ctrl & TRF7970A_CHIP_STATUS_RF_ON)) {
 931                 ret = trf7970a_write(trf, TRF7970A_CHIP_STATUS_CTRL,
 932                                 trf->chip_status_ctrl |
 933                                         TRF7970A_CHIP_STATUS_RF_ON);
 934                 if (ret)
 935                         return ret;
 936
 937                 trf->chip_status_ctrl |= TRF7970A_CHIP_STATUS_RF_ON;
 938
 939                 usleep_range(5000, 6000);
 940         }
 941
 942         return 0;
 943 }
 944
 945 static int trf7970a_in_configure_hw(struct nfc_digital_dev *ddev, int type,
 946                 int param)
 947 {
 948         struct trf7970a *trf = nfc_digital_get_drvdata(ddev);
 949         int ret;
 950
 951         dev_dbg(trf->dev, "Configure hw - type: %d, param: %d\n", type, param);
 952
 953         mutex_lock(&trf->lock);
 954
 955         if (trf->state == TRF7970A_ST_OFF)
 956                 trf7970a_switch_rf_on(trf);
 957
 958         switch (type) {
 959         case NFC_DIGITAL_CONFIG_RF_TECH:
 960                 ret = trf7970a_config_rf_tech(trf, param);
 961                 break;
 962         case NFC_DIGITAL_CONFIG_FRAMING:
 963                 ret = trf7970a_config_framing(trf, param);
 964                 break;
 965         default:
 966                 dev_dbg(trf->dev, "Unknown type: %d\n", type);
 967                 ret = -EINVAL;
 968         }
 969
 970         mutex_unlock(&trf->lock);
 971         return ret;
 972 }
 973
 974 static int trf7970a_is_iso15693_write_or_lock(u8 cmd)
 975 {
 976         switch (cmd) {
 977         case ISO15693_CMD_WRITE_SINGLE_BLOCK:
 978         case ISO15693_CMD_LOCK_BLOCK:
 979         case ISO15693_CMD_WRITE_MULTIPLE_BLOCK:
 980         case ISO15693_CMD_WRITE_AFI:
 981         case ISO15693_CMD_LOCK_AFI:
 982         case ISO15693_CMD_WRITE_DSFID:
 983         case ISO15693_CMD_LOCK_DSFID:
 984                 return 1;
 985                 break;
 986         default:
 987                 return 0;
 988         }
 989 }
 990
 991 static int trf7970a_per_cmd_config(struct trf7970a *trf, struct sk_buff *skb)
 992 {
 993         u8 *req = skb->data;
 994         u8 special_fcn_reg1, iso_ctrl;
 995         int ret;
 996
 997         trf->issue_eof = false;
 998
 999         /* When issuing Type 2 read command, make sure the '4_bit_RX' bit in
1000          * special functions register 1 is cleared; otherwise, its a write or
1001          * sector select command and '4_bit_RX' must be set.
1002          *
1003          * When issuing an ISO 15693 command, inspect the flags byte to see
1004          * what speed to use.  Also, remember if the OPTION flag is set on
1005          * a Type 5 write or lock command so the driver will know that it
1006          * has to send an EOF in order to get a response.
1007          */
1008         if ((trf->technology == NFC_DIGITAL_RF_TECH_106A) &&
1009                         (trf->framing == NFC_DIGITAL_FRAMING_NFCA_T2T)) {
1010                 if (req[0] == NFC_T2T_CMD_READ)
1011                         special_fcn_reg1 = 0;
1012                 else
1013                         special_fcn_reg1 = TRF7970A_SPECIAL_FCN_REG1_4_BIT_RX;
1014
1015                 if (special_fcn_reg1 != trf->special_fcn_reg1) {
1016                         ret = trf7970a_write(trf, TRF7970A_SPECIAL_FCN_REG1,
1017                                         special_fcn_reg1);
1018                         if (ret)
1019                                 return ret;
1020
1021                         trf->special_fcn_reg1 = special_fcn_reg1;
1022                 }
1023         } else if (trf->technology == NFC_DIGITAL_RF_TECH_ISO15693) {
1024                 iso_ctrl = trf->iso_ctrl & ~TRF7970A_ISO_CTRL_RFID_SPEED_MASK;
1025
1026                 switch (req[0] & ISO15693_REQ_FLAG_SPEED_MASK) {
1027                 case 0x00:
1028                         iso_ctrl |= TRF7970A_ISO_CTRL_15693_SGL_1OF4_662;
1029                         break;
1030                 case ISO15693_REQ_FLAG_SUB_CARRIER:
1031                         iso_ctrl |= TRF7970A_ISO_CTRL_15693_DBL_1OF4_667a;
1032                         break;
1033                 case ISO15693_REQ_FLAG_DATA_RATE:
1034                         iso_ctrl |= TRF7970A_ISO_CTRL_15693_SGL_1OF4_2648;
1035                         break;
1036                 case (ISO15693_REQ_FLAG_SUB_CARRIER |
1037                                 ISO15693_REQ_FLAG_DATA_RATE):
1038                         iso_ctrl |= TRF7970A_ISO_CTRL_15693_DBL_1OF4_2669;
1039                         break;
1040                 }
1041
1042                 if (iso_ctrl != trf->iso_ctrl) {
1043                         ret = trf7970a_write(trf, TRF7970A_ISO_CTRL, iso_ctrl);
1044                         if (ret)
1045                                 return ret;
1046
1047                         trf->iso_ctrl = iso_ctrl;
1048                 }
1049
1050                 if ((trf->framing == NFC_DIGITAL_FRAMING_ISO15693_T5T) &&
1051                                 trf7970a_is_iso15693_write_or_lock(req[1]) &&
1052                                 (req[0] & ISO15693_REQ_FLAG_OPTION))
1053                         trf->issue_eof = true;
1054         }
1055
1056         return 0;
1057 }
1058
1059 static int trf7970a_in_send_cmd(struct nfc_digital_dev *ddev,
1060                 struct sk_buff *skb, u16 timeout,
1061                 nfc_digital_cmd_complete_t cb, void *arg)
1062 {
1063         struct trf7970a *trf = nfc_digital_get_drvdata(ddev);
1064         char *prefix;
1065         unsigned int len;
1066         int ret;
1067
1068         dev_dbg(trf->dev, "New request - state: %d, timeout: %d ms, len: %d\n",
1069                         trf->state, timeout, skb->len);
1070
1071         if (skb->len > TRF7970A_TX_MAX)
1072                 return -EINVAL;
1073
1074         mutex_lock(&trf->lock);
1075
1076         if ((trf->state != TRF7970A_ST_IDLE) &&
1077                         (trf->state != TRF7970A_ST_IDLE_RX_BLOCKED)) {
1078                 dev_err(trf->dev, "%s - Bogus state: %d\n", __func__,
1079                                 trf->state);
1080                 ret = -EIO;
1081                 goto out_err;
1082         }
1083
1084         if (trf->aborting) {
1085                 dev_dbg(trf->dev, "Abort process complete\n");
1086                 trf->aborting = false;
1087                 ret = -ECANCELED;
1088                 goto out_err;
1089         }
1090
1091         trf->rx_skb = nfc_alloc_recv_skb(TRF7970A_RX_SKB_ALLOC_SIZE,
1092                         GFP_KERNEL);
1093         if (!trf->rx_skb) {
1094                 dev_dbg(trf->dev, "Can't alloc rx_skb\n");
1095                 ret = -ENOMEM;
1096                 goto out_err;
1097         }
1098
1099         if (trf->state == TRF7970A_ST_IDLE_RX_BLOCKED) {
1100                 ret = trf7970a_cmd(trf, TRF7970A_CMD_ENABLE_RX);
1101                 if (ret)
1102                         goto out_err;
1103
1104                 trf->state = TRF7970A_ST_IDLE;
1105         }
1106
1107         ret = trf7970a_per_cmd_config(trf, skb);
1108         if (ret)
1109                 goto out_err;
1110
1111         trf->ddev = ddev;
1112         trf->tx_skb = skb;
1113         trf->cb = cb;
1114         trf->cb_arg = arg;
1115         trf->timeout = timeout;
1116         trf->ignore_timeout = false;
1117
1118         len = skb->len;
1119         prefix = skb_push(skb, TRF7970A_TX_SKB_HEADROOM);
1120
1121         /* TX data must be prefixed with a FIFO reset cmd, a cmd that depends
1122          * on what the current framing is, the address of the TX length byte 1
1123          * register (0x1d), and the 2 byte length of the data to be transmitted.
1124          */
1125         prefix[0] = TRF7970A_CMD_BIT_CTRL |
1126                         TRF7970A_CMD_BIT_OPCODE(TRF7970A_CMD_FIFO_RESET);
1127         prefix[1] = TRF7970A_CMD_BIT_CTRL |
1128                         TRF7970A_CMD_BIT_OPCODE(trf->tx_cmd);
1129         prefix[2] = TRF7970A_CMD_BIT_CONTINUOUS | TRF7970A_TX_LENGTH_BYTE1;
1130
1131         if (trf->framing == NFC_DIGITAL_FRAMING_NFCA_SHORT) {
1132                 prefix[3] = 0x00;
1133                 prefix[4] = 0x0f; /* 7 bits */
1134         } else {
1135                 prefix[3] = (len & 0xf00) >> 4;
1136                 prefix[3] |= ((len & 0xf0) >> 4);
1137                 prefix[4] = ((len & 0x0f) << 4);
1138         }
1139
1140         len = min_t(int, skb->len, TRF7970A_FIFO_SIZE);
1141
1142         usleep_range(1000, 2000);
1143
1144         ret = trf7970a_transmit(trf, skb, len);
1145         if (ret) {
1146                 kfree_skb(trf->rx_skb);
1147                 trf->rx_skb = NULL;
1148         }
1149
1150 out_err:
1151         mutex_unlock(&trf->lock);
1152         return ret;
1153 }
1154
1155 static int trf7970a_tg_configure_hw(struct nfc_digital_dev *ddev,
1156                 int type, int param)
1157 {
1158         struct trf7970a *trf = nfc_digital_get_drvdata(ddev);
1159
1160         dev_dbg(trf->dev, "Unsupported interface\n");
1161
1162         return -EINVAL;
1163 }
1164
1165 static int trf7970a_tg_send_cmd(struct nfc_digital_dev *ddev,
1166                 struct sk_buff *skb, u16 timeout,
1167                 nfc_digital_cmd_complete_t cb, void *arg)
1168 {
1169         struct trf7970a *trf = nfc_digital_get_drvdata(ddev);
1170
1171         dev_dbg(trf->dev, "Unsupported interface\n");
1172
1173         return -EINVAL;
1174 }
1175
1176 static int trf7970a_tg_listen(struct nfc_digital_dev *ddev,
1177                 u16 timeout, nfc_digital_cmd_complete_t cb, void *arg)
1178 {
1179         struct trf7970a *trf = nfc_digital_get_drvdata(ddev);
1180
1181         dev_dbg(trf->dev, "Unsupported interface\n");
1182
1183         return -EINVAL;
1184 }
1185
1186 static int trf7970a_tg_listen_mdaa(struct nfc_digital_dev *ddev,
1187                 struct digital_tg_mdaa_params *mdaa_params,
1188                 u16 timeout, nfc_digital_cmd_complete_t cb, void *arg)
1189 {
1190         struct trf7970a *trf = nfc_digital_get_drvdata(ddev);
1191
1192         dev_dbg(trf->dev, "Unsupported interface\n");
1193
1194         return -EINVAL;
1195 }
1196
1197 static void trf7970a_abort_cmd(struct nfc_digital_dev *ddev)
1198 {
1199         struct trf7970a *trf = nfc_digital_get_drvdata(ddev);
1200
1201         dev_dbg(trf->dev, "Abort process initiated\n");
1202
1203         mutex_lock(&trf->lock);
1204
1205         switch (trf->state) {
1206         case TRF7970A_ST_WAIT_FOR_TX_FIFO:
1207         case TRF7970A_ST_WAIT_FOR_RX_DATA:
1208         case TRF7970A_ST_WAIT_FOR_RX_DATA_CONT:
1209         case TRF7970A_ST_WAIT_TO_ISSUE_EOF:
1210                 trf->aborting = true;
1211                 break;
1212         default:
1213                 break;
1214         }
1215
1216         mutex_unlock(&trf->lock);
1217 }
1218
1219 static struct nfc_digital_ops trf7970a_nfc_ops = {
1220         .in_configure_hw        = trf7970a_in_configure_hw,
1221         .in_send_cmd            = trf7970a_in_send_cmd,
1222         .tg_configure_hw        = trf7970a_tg_configure_hw,
1223         .tg_send_cmd            = trf7970a_tg_send_cmd,
1224         .tg_listen              = trf7970a_tg_listen,
1225         .tg_listen_mdaa         = trf7970a_tg_listen_mdaa,
1226         .switch_rf              = trf7970a_switch_rf,
1227         .abort_cmd              = trf7970a_abort_cmd,
1228 };
1229
1230 static int trf7970a_get_autosuspend_delay(struct device_node *np)
1231 {
1232         int autosuspend_delay, ret;
1233
1234         ret = of_property_read_u32(np, "autosuspend-delay", &autosuspend_delay);
1235         if (ret)
1236                 autosuspend_delay = TRF7970A_AUTOSUSPEND_DELAY;
1237
1238         of_node_put(np);
1239
1240         return autosuspend_delay;
1241 }
1242
1243 static int trf7970a_probe(struct spi_device *spi)
1244 {
1245         struct device_node *np = spi->dev.of_node;
1246         const struct spi_device_id *id = spi_get_device_id(spi);
1247         struct trf7970a *trf;
1248         int uvolts, autosuspend_delay, ret;
1249
1250         if (!np) {
1251                 dev_err(&spi->dev, "No Device Tree entry\n");
1252                 return -EINVAL;
1253         }
1254
1255         trf = devm_kzalloc(&spi->dev, sizeof(*trf), GFP_KERNEL);
1256         if (!trf)
1257                 return -ENOMEM;
1258
1259         trf->state = TRF7970A_ST_OFF;
1260         trf->dev = &spi->dev;
1261         trf->spi = spi;
1262         trf->quirks = id->driver_data;
1263
1264         spi->mode = SPI_MODE_1;
1265         spi->bits_per_word = 8;
1266
1267         /* There are two enable pins - both must be present */
1268         trf->en_gpio = of_get_named_gpio(np, "ti,enable-gpios", 0);
1269         if (!gpio_is_valid(trf->en_gpio)) {
1270                 dev_err(trf->dev, "No EN GPIO property\n");
1271                 return trf->en_gpio;
1272         }
1273
1274         ret = devm_gpio_request_one(trf->dev, trf->en_gpio,
1275                         GPIOF_DIR_OUT | GPIOF_INIT_LOW, "EN");
1276         if (ret) {
1277                 dev_err(trf->dev, "Can't request EN GPIO: %d\n", ret);
1278                 return ret;
1279         }
1280
1281         trf->en2_gpio = of_get_named_gpio(np, "ti,enable-gpios", 1);
1282         if (!gpio_is_valid(trf->en2_gpio)) {
1283                 dev_err(trf->dev, "No EN2 GPIO property\n");
1284                 return trf->en2_gpio;
1285         }
1286
1287         ret = devm_gpio_request_one(trf->dev, trf->en2_gpio,
1288                         GPIOF_DIR_OUT | GPIOF_INIT_LOW, "EN2");
1289         if (ret) {
1290                 dev_err(trf->dev, "Can't request EN2 GPIO: %d\n", ret);
1291                 return ret;
1292         }
1293
1294         ret = devm_request_threaded_irq(trf->dev, spi->irq, NULL,
1295                         trf7970a_irq, IRQF_TRIGGER_RISING | IRQF_ONESHOT,
1296                         "trf7970a", trf);
1297         if (ret) {
1298                 dev_err(trf->dev, "Can't request IRQ#%d: %d\n", spi->irq, ret);
1299                 return ret;
1300         }
1301
1302         mutex_init(&trf->lock);
1303         INIT_DELAYED_WORK(&trf->timeout_work, trf7970a_timeout_work_handler);
1304
1305         trf->regulator = devm_regulator_get(&spi->dev, "vin");
1306         if (IS_ERR(trf->regulator)) {
1307                 ret = PTR_ERR(trf->regulator);
1308                 dev_err(trf->dev, "Can't get VIN regulator: %d\n", ret);
1309                 goto err_destroy_lock;
1310         }
1311
1312         ret = regulator_enable(trf->regulator);
1313         if (ret) {
1314                 dev_err(trf->dev, "Can't enable VIN: %d\n", ret);
1315                 goto err_destroy_lock;
1316         }
1317
1318         uvolts = regulator_get_voltage(trf->regulator);
1319
1320         if (uvolts > 4000000)
1321                 trf->chip_status_ctrl = TRF7970A_CHIP_STATUS_VRS5_3;
1322
1323         trf->ddev = nfc_digital_allocate_device(&trf7970a_nfc_ops,
1324                         TRF7970A_SUPPORTED_PROTOCOLS,
1325                         NFC_DIGITAL_DRV_CAPS_IN_CRC, TRF7970A_TX_SKB_HEADROOM,
1326                         0);
1327         if (!trf->ddev) {
1328                 dev_err(trf->dev, "Can't allocate NFC digital device\n");
1329                 ret = -ENOMEM;
1330                 goto err_disable_regulator;
1331         }
1332
1333         nfc_digital_set_parent_dev(trf->ddev, trf->dev);
1334         nfc_digital_set_drvdata(trf->ddev, trf);
1335         spi_set_drvdata(spi, trf);
1336
1337         autosuspend_delay = trf7970a_get_autosuspend_delay(np);
1338
1339         pm_runtime_set_autosuspend_delay(trf->dev, autosuspend_delay);
1340         pm_runtime_use_autosuspend(trf->dev);
1341         pm_runtime_enable(trf->dev);
1342
1343         ret = nfc_digital_register_device(trf->ddev);
1344         if (ret) {
1345                 dev_err(trf->dev, "Can't register NFC digital device: %d\n",
1346                                 ret);
1347                 goto err_free_ddev;
1348         }
1349
1350         return 0;
1351
1352 err_free_ddev:
1353         pm_runtime_disable(trf->dev);
1354         nfc_digital_free_device(trf->ddev);
1355 err_disable_regulator:
1356         regulator_disable(trf->regulator);
1357 err_destroy_lock:
1358         mutex_destroy(&trf->lock);
1359         return ret;
1360 }
1361
1362 static int trf7970a_remove(struct spi_device *spi)
1363 {
1364         struct trf7970a *trf = spi_get_drvdata(spi);
1365
1366         mutex_lock(&trf->lock);
1367
1368         switch (trf->state) {
1369         case TRF7970A_ST_WAIT_FOR_TX_FIFO:
1370         case TRF7970A_ST_WAIT_FOR_RX_DATA:
1371         case TRF7970A_ST_WAIT_FOR_RX_DATA_CONT:
1372         case TRF7970A_ST_WAIT_TO_ISSUE_EOF:
1373                 trf7970a_send_err_upstream(trf, -ECANCELED);
1374                 /* FALLTHROUGH */
1375         case TRF7970A_ST_IDLE:
1376         case TRF7970A_ST_IDLE_RX_BLOCKED:
1377                 pm_runtime_put_sync(trf->dev);
1378                 break;
1379         default:
1380                 break;
1381         }
1382
1383         mutex_unlock(&trf->lock);
1384
1385         pm_runtime_disable(trf->dev);
1386
1387         nfc_digital_unregister_device(trf->ddev);
1388         nfc_digital_free_device(trf->ddev);
1389
1390         regulator_disable(trf->regulator);
1391
1392         mutex_destroy(&trf->lock);
1393
1394         return 0;
1395 }
1396
1397 #ifdef CONFIG_PM_RUNTIME
1398 static int trf7970a_pm_runtime_suspend(struct device *dev)
1399 {
1400         struct spi_device *spi = container_of(dev, struct spi_device, dev);
1401         struct trf7970a *trf = spi_get_drvdata(spi);
1402         int ret;
1403
1404         dev_dbg(dev, "Runtime suspend\n");
1405
1406         if (trf->state != TRF7970A_ST_OFF) {
1407                 dev_dbg(dev, "Can't suspend - not in OFF state (%d)\n",
1408                                 trf->state);
1409                 return -EBUSY;
1410         }
1411
1412         gpio_set_value(trf->en_gpio, 0);
1413         gpio_set_value(trf->en2_gpio, 0);
1414
1415         ret = regulator_disable(trf->regulator);
1416         if (ret)
1417                 dev_err(dev, "%s - Can't disable VIN: %d\n", __func__, ret);
1418
1419         return ret;
1420 }
1421
1422 static int trf7970a_pm_runtime_resume(struct device *dev)
1423 {
1424         struct spi_device *spi = container_of(dev, struct spi_device, dev);
1425         struct trf7970a *trf = spi_get_drvdata(spi);
1426         int ret;
1427
1428         dev_dbg(dev, "Runtime resume\n");
1429
1430         ret = regulator_enable(trf->regulator);
1431         if (ret) {
1432                 dev_err(dev, "%s - Can't enable VIN: %d\n", __func__, ret);
1433                 return ret;
1434         }
1435
1436         usleep_range(5000, 6000);
1437
1438         gpio_set_value(trf->en2_gpio, 1);
1439         usleep_range(1000, 2000);
1440         gpio_set_value(trf->en_gpio, 1);
1441
1442         usleep_range(20000, 21000);
1443
1444         ret = trf7970a_init(trf);
1445         if (ret) {
1446                 dev_err(dev, "%s - Can't initialize: %d\n", __func__, ret);
1447                 return ret;
1448         }
1449
1450         pm_runtime_mark_last_busy(dev);
1451
1452         return 0;
1453 }
1454 #endif
1455
1456 static const struct dev_pm_ops trf7970a_pm_ops = {
1457         SET_RUNTIME_PM_OPS(trf7970a_pm_runtime_suspend,
1458                         trf7970a_pm_runtime_resume, NULL)
1459 };
1460
1461 static const struct spi_device_id trf7970a_id_table[] = {
1462         { "trf7970a", TRF7970A_QUIRK_IRQ_STATUS_READ_ERRATA },
1463         { }
1464 };
1465 MODULE_DEVICE_TABLE(spi, trf7970a_id_table);
1466
1467 static struct spi_driver trf7970a_spi_driver = {
1468         .probe          = trf7970a_probe,
1469         .remove         = trf7970a_remove,
1470         .id_table       = trf7970a_id_table,
1471         .driver         = {
1472                 .name   = "trf7970a",
1473                 .owner  = THIS_MODULE,
1474                 .pm     = &trf7970a_pm_ops,
1475         },
1476 };
1477
1478 module_spi_driver(trf7970a_spi_driver);
1479
1480 MODULE_AUTHOR("Mark A. Greer <mgreer@animalcreek.com>");
1481 MODULE_LICENSE("GPL v2");
1482 MODULE_DESCRIPTION("TI trf7970a RFID/NFC Transceiver Driver");