arch/powerpc/boot/mv64x60_i2c.c

   1 /*
   2  * Bootloader version of the i2c driver for the MV64x60.
   3  *
   4  * Author: Dale Farnsworth <dfarnsworth@mvista.com>
   5  * Maintained by: Mark A. Greer <mgreer@mvista.com>
   6  *
   7  * 2003, 2007 (c) MontaVista, Software, Inc.  This file is licensed under
   8  * the terms of the GNU General Public License version 2.  This program is
   9  * licensed "as is" without any warranty of any kind, whether express or
  10  * implied.
  11  */
  12
  13 #include <stdarg.h>
  14 #include <stddef.h>
  15 #include "types.h"
  16 #include "elf.h"
  17 #include "page.h"
  18 #include "string.h"
  19 #include "stdio.h"
  20 #include "io.h"
  21 #include "ops.h"
  22 #include "mv64x60.h"
  23
  24 extern void udelay(long);
  25
  26 /* Register defines */
  27 #define MV64x60_I2C_REG_SLAVE_ADDR                      0x00
  28 #define MV64x60_I2C_REG_DATA                            0x04
  29 #define MV64x60_I2C_REG_CONTROL                         0x08
  30 #define MV64x60_I2C_REG_STATUS                          0x0c
  31 #define MV64x60_I2C_REG_BAUD                            0x0c
  32 #define MV64x60_I2C_REG_EXT_SLAVE_ADDR                  0x10
  33 #define MV64x60_I2C_REG_SOFT_RESET                      0x1c
  34
  35 #define MV64x60_I2C_CONTROL_ACK                         0x04
  36 #define MV64x60_I2C_CONTROL_IFLG                        0x08
  37 #define MV64x60_I2C_CONTROL_STOP                        0x10
  38 #define MV64x60_I2C_CONTROL_START                       0x20
  39 #define MV64x60_I2C_CONTROL_TWSIEN                      0x40
  40 #define MV64x60_I2C_CONTROL_INTEN                       0x80
  41
  42 #define MV64x60_I2C_STATUS_BUS_ERR                      0x00
  43 #define MV64x60_I2C_STATUS_MAST_START                   0x08
  44 #define MV64x60_I2C_STATUS_MAST_REPEAT_START            0x10
  45 #define MV64x60_I2C_STATUS_MAST_WR_ADDR_ACK             0x18
  46 #define MV64x60_I2C_STATUS_MAST_WR_ADDR_NO_ACK          0x20
  47 #define MV64x60_I2C_STATUS_MAST_WR_ACK                  0x28
  48 #define MV64x60_I2C_STATUS_MAST_WR_NO_ACK               0x30
  49 #define MV64x60_I2C_STATUS_MAST_LOST_ARB                0x38
  50 #define MV64x60_I2C_STATUS_MAST_RD_ADDR_ACK             0x40
  51 #define MV64x60_I2C_STATUS_MAST_RD_ADDR_NO_ACK          0x48
  52 #define MV64x60_I2C_STATUS_MAST_RD_DATA_ACK             0x50
  53 #define MV64x60_I2C_STATUS_MAST_RD_DATA_NO_ACK          0x58
  54 #define MV64x60_I2C_STATUS_MAST_WR_ADDR_2_ACK           0xd0
  55 #define MV64x60_I2C_STATUS_MAST_WR_ADDR_2_NO_ACK        0xd8
  56 #define MV64x60_I2C_STATUS_MAST_RD_ADDR_2_ACK           0xe0
  57 #define MV64x60_I2C_STATUS_MAST_RD_ADDR_2_NO_ACK        0xe8
  58 #define MV64x60_I2C_STATUS_NO_STATUS                    0xf8
  59
  60 static u8 *ctlr_base;
  61
  62 static int mv64x60_i2c_wait_for_status(int wanted)
  63 {
  64         int i;
  65         int status;
  66
  67         for (i=0; i<1000; i++) {
  68                 udelay(10);
  69                 status = in_le32((u32 *)(ctlr_base + MV64x60_I2C_REG_STATUS))
  70                         & 0xff;
  71                 if (status == wanted)
  72                         return status;
  73         }
  74         return -status;
  75 }
  76
  77 static int mv64x60_i2c_control(int control, int status)
  78 {
  79         out_le32((u32 *)(ctlr_base + MV64x60_I2C_REG_CONTROL), control & 0xff);
  80         return mv64x60_i2c_wait_for_status(status);
  81 }
  82
  83 static int mv64x60_i2c_read_byte(int control, int status)
  84 {
  85         out_le32((u32 *)(ctlr_base + MV64x60_I2C_REG_CONTROL), control & 0xff);
  86         if (mv64x60_i2c_wait_for_status(status) < 0)
  87                 return -1;
  88         return in_le32((u32 *)(ctlr_base + MV64x60_I2C_REG_DATA)) & 0xff;
  89 }
  90
  91 static int mv64x60_i2c_write_byte(int data, int control, int status)
  92 {
  93         out_le32((u32 *)(ctlr_base + MV64x60_I2C_REG_DATA), data & 0xff);
  94         out_le32((u32 *)(ctlr_base + MV64x60_I2C_REG_CONTROL), control & 0xff);
  95         return mv64x60_i2c_wait_for_status(status);
  96 }
  97
  98 int mv64x60_i2c_read(u32 devaddr, u8 *buf, u32 offset, u32 offset_size,
  99                  u32 count)
 100 {
 101         int i;
 102         int data;
 103         int control;
 104         int status;
 105
 106         if (ctlr_base == NULL)
 107                 return -1;
 108
 109         /* send reset */
 110         out_le32((u32 *)(ctlr_base + MV64x60_I2C_REG_SOFT_RESET), 0);
 111         out_le32((u32 *)(ctlr_base + MV64x60_I2C_REG_SLAVE_ADDR), 0);
 112         out_le32((u32 *)(ctlr_base + MV64x60_I2C_REG_EXT_SLAVE_ADDR), 0);
 113         out_le32((u32 *)(ctlr_base + MV64x60_I2C_REG_BAUD), (4 << 3) | 0x4);
 114
 115         if (mv64x60_i2c_control(MV64x60_I2C_CONTROL_TWSIEN,
 116                                 MV64x60_I2C_STATUS_NO_STATUS) < 0)
 117                 return -1;
 118
 119         /* send start */
 120         control = MV64x60_I2C_CONTROL_START | MV64x60_I2C_CONTROL_TWSIEN;
 121         status = MV64x60_I2C_STATUS_MAST_START;
 122         if (mv64x60_i2c_control(control, status) < 0)
 123                 return -1;
 124
 125         /* select device for writing */
 126         data = devaddr & ~0x1;
 127         control = MV64x60_I2C_CONTROL_TWSIEN;
 128         status = MV64x60_I2C_STATUS_MAST_WR_ADDR_ACK;
 129         if (mv64x60_i2c_write_byte(data, control, status) < 0)
 130                 return -1;
 131
 132         /* send offset of data */
 133         control = MV64x60_I2C_CONTROL_TWSIEN;
 134         status = MV64x60_I2C_STATUS_MAST_WR_ACK;
 135         if (offset_size > 1) {
 136                 if (mv64x60_i2c_write_byte(offset >> 8, control, status) < 0)
 137                         return -1;
 138         }
 139         if (mv64x60_i2c_write_byte(offset, control, status) < 0)
 140                 return -1;
 141
 142         /* resend start */
 143         control = MV64x60_I2C_CONTROL_START | MV64x60_I2C_CONTROL_TWSIEN;
 144         status = MV64x60_I2C_STATUS_MAST_REPEAT_START;
 145         if (mv64x60_i2c_control(control, status) < 0)
 146                 return -1;
 147
 148         /* select device for reading */
 149         data = devaddr | 0x1;
 150         control = MV64x60_I2C_CONTROL_TWSIEN;
 151         status = MV64x60_I2C_STATUS_MAST_RD_ADDR_ACK;
 152         if (mv64x60_i2c_write_byte(data, control, status) < 0)
 153                 return -1;
 154
 155         /* read all but last byte of data */
 156         control = MV64x60_I2C_CONTROL_ACK | MV64x60_I2C_CONTROL_TWSIEN;
 157         status = MV64x60_I2C_STATUS_MAST_RD_DATA_ACK;
 158
 159         for (i=1; i<count; i++) {
 160                 data = mv64x60_i2c_read_byte(control, status);
 161                 if (data < 0) {
 162                         printf("errors on iteration %d\n", i);
 163                         return -1;
 164                 }
 165                 *buf++ = data;
 166         }
 167
 168         /* read last byte of data */
 169         control = MV64x60_I2C_CONTROL_TWSIEN;
 170         status = MV64x60_I2C_STATUS_MAST_RD_DATA_NO_ACK;
 171         data = mv64x60_i2c_read_byte(control, status);
 172         if (data < 0)
 173                 return -1;
 174         *buf++ = data;
 175
 176         /* send stop */
 177         control = MV64x60_I2C_CONTROL_STOP | MV64x60_I2C_CONTROL_TWSIEN;
 178         status = MV64x60_I2C_STATUS_NO_STATUS;
 179         if (mv64x60_i2c_control(control, status) < 0)
 180                 return -1;
 181
 182         return count;
 183 }
 184
 185 int mv64x60_i2c_open(void)
 186 {
 187         u32 v;
 188         void *devp;
 189
 190         devp = finddevice("/mv64x60/i2c");
 191         if (devp == NULL)
 192                 goto err_out;
 193         if (getprop(devp, "virtual-reg", &v, sizeof(v)) != sizeof(v))
 194                 goto err_out;
 195
 196         ctlr_base = (u8 *)v;
 197         return 0;
 198
 199 err_out:
 200         return -1;
 201 }
 202
 203 void mv64x60_i2c_close(void)
 204 {
 205         ctlr_base = NULL;
 206 }