arch/arm/mach-u300/padmux.c

   1 /*
   2  *
   3  * arch/arm/mach-u300/padmux.c
   4  *
   5  *
   6  * Copyright (C) 2009 ST-Ericsson AB
   7  * License terms: GNU General Public License (GPL) version 2
   8  * U300 PADMUX functions
   9  * Author: Martin Persson <martin.persson@stericsson.com>
  10  */
  11
  12 #include <linux/module.h>
  13 #include <linux/kernel.h>
  14 #include <linux/device.h>
  15 #include <linux/err.h>
  16 #include <linux/errno.h>
  17 #include <linux/io.h>
  18 #include <linux/mutex.h>
  19 #include <linux/string.h>
  20 #include <linux/bug.h>
  21 #include <linux/debugfs.h>
  22 #include <linux/seq_file.h>
  23 #include <mach/u300-regs.h>
  24 #include <mach/syscon.h>
  25 #include "padmux.h"
  26
  27 static DEFINE_MUTEX(pmx_mutex);
  28
  29 const u32 pmx_registers[] = {
  30         (U300_SYSCON_VBASE + U300_SYSCON_PMC1LR),
  31         (U300_SYSCON_VBASE + U300_SYSCON_PMC1HR),
  32         (U300_SYSCON_VBASE + U300_SYSCON_PMC2R),
  33         (U300_SYSCON_VBASE + U300_SYSCON_PMC3R),
  34         (U300_SYSCON_VBASE + U300_SYSCON_PMC4R)
  35 };
  36
  37 /* High level functionality */
  38
  39 /* Lazy dog:
  40  * onmask = {
  41  *   {"PMC1LR" mask, "PMC1LR" value},
  42  *   {"PMC1HR" mask, "PMC1HR" value},
  43  *   {"PMC2R"  mask, "PMC2R"  value},
  44  *   {"PMC3R"  mask, "PMC3R"  value},
  45  *   {"PMC4R"  mask, "PMC4R"  value}
  46  * }
  47  */
  48 static struct pmx mmc_setting = {
  49         .setting = U300_APP_PMX_MMC_SETTING,
  50         .default_on = false,
  51         .activated = false,
  52         .name = "MMC",
  53         .onmask = {
  54                    {U300_SYSCON_PMC1LR_MMCSD_MASK,
  55                     U300_SYSCON_PMC1LR_MMCSD_MMCSD},
  56                    {0, 0},
  57                    {0, 0},
  58                    {0, 0},
  59                    {U300_SYSCON_PMC4R_APP_MISC_12_MASK,
  60                     U300_SYSCON_PMC4R_APP_MISC_12_APP_GPIO}
  61                    },
  62 };
  63
  64 static struct pmx spi_setting = {
  65         .setting = U300_APP_PMX_SPI_SETTING,
  66         .default_on = false,
  67         .activated = false,
  68         .name = "SPI",
  69         .onmask = {{0, 0},
  70                    {U300_SYSCON_PMC1HR_APP_SPI_2_MASK |
  71                     U300_SYSCON_PMC1HR_APP_SPI_CS_1_MASK |
  72                     U300_SYSCON_PMC1HR_APP_SPI_CS_2_MASK,
  73                     U300_SYSCON_PMC1HR_APP_SPI_2_SPI |
  74                     U300_SYSCON_PMC1HR_APP_SPI_CS_1_SPI |
  75                     U300_SYSCON_PMC1HR_APP_SPI_CS_2_SPI},
  76                    {0, 0},
  77                    {0, 0},
  78                    {0, 0}
  79                    },
  80 };
  81
  82 /* Available padmux settings */
  83 static struct pmx *pmx_settings[] = {
  84         &mmc_setting,
  85         &spi_setting,
  86 };
  87
  88 static void update_registers(struct pmx *pmx, bool activate)
  89 {
  90         u16 regval, val, mask;
  91         int i;
  92
  93         for (i = 0; i < ARRAY_SIZE(pmx_registers); i++) {
  94                 if (activate)
  95                         val = pmx->onmask[i].val;
  96                 else
  97                         val = 0;
  98
  99                 mask = pmx->onmask[i].mask;
 100                 if (mask != 0) {
 101                         regval = readw(pmx_registers[i]);
 102                         regval &= ~mask;
 103                         regval |= val;
 104                         writew(regval, pmx_registers[i]);
 105                 }
 106         }
 107 }
 108
 109 struct pmx *pmx_get(struct device *dev, enum pmx_settings setting)
 110 {
 111         int i;
 112         struct pmx *pmx = ERR_PTR(-ENOENT);
 113
 114         if (dev == NULL)
 115                 return ERR_PTR(-EINVAL);
 116
 117         mutex_lock(&pmx_mutex);
 118         for (i = 0; i < ARRAY_SIZE(pmx_settings); i++) {
 119
 120                 if (setting == pmx_settings[i]->setting) {
 121
 122                         if (pmx_settings[i]->dev != NULL) {
 123                                 WARN(1, "padmux: required setting "
 124                                      "in use by another consumer\n");
 125                         } else {
 126                                 pmx = pmx_settings[i];
 127                                 pmx->dev = dev;
 128                                 dev_dbg(dev, "padmux: setting nr %d is now "
 129                                         "bound to %s and ready to use\n",
 130                                         setting, dev_name(dev));
 131                                 break;
 132                         }
 133                 }
 134         }
 135         mutex_unlock(&pmx_mutex);
 136
 137         return pmx;
 138 }
 139 EXPORT_SYMBOL(pmx_get);
 140
 141 int pmx_put(struct device *dev, struct pmx *pmx)
 142 {
 143         int i;
 144         int ret = -ENOENT;
 145
 146         if (pmx == NULL || dev == NULL)
 147                 return -EINVAL;
 148
 149         mutex_lock(&pmx_mutex);
 150         for (i = 0; i < ARRAY_SIZE(pmx_settings); i++) {
 151
 152                 if (pmx->setting == pmx_settings[i]->setting) {
 153
 154                         if (dev != pmx->dev) {
 155                                 WARN(1, "padmux: cannot release handle as "
 156                                         "it is bound to another consumer\n");
 157                                 ret = -EINVAL;
 158                                 break;
 159                         } else {
 160                                 pmx_settings[i]->dev = NULL;
 161                                 ret = 0;
 162                                 break;
 163                         }
 164                 }
 165         }
 166         mutex_unlock(&pmx_mutex);
 167
 168         return ret;
 169 }
 170 EXPORT_SYMBOL(pmx_put);
 171
 172 int pmx_activate(struct device *dev, struct pmx *pmx)
 173 {
 174         int i, j, ret;
 175         ret = 0;
 176
 177         if (pmx == NULL || dev == NULL)
 178                 return -EINVAL;
 179
 180         mutex_lock(&pmx_mutex);
 181
 182         /* Make sure the required bits are not used */
 183         for (i = 0; i < ARRAY_SIZE(pmx_settings); i++) {
 184
 185                 if (pmx_settings[i]->dev == NULL || pmx_settings[i] == pmx)
 186                         continue;
 187
 188                 for (j = 0; j < ARRAY_SIZE(pmx_registers); j++) {
 189
 190                         if (pmx_settings[i]->onmask[j].mask & pmx->
 191                                 onmask[j].mask) {
 192                                 /* More than one entry on the same bits */
 193                                 WARN(1, "padmux: cannot activate "
 194                                         "setting. Bit conflict with "
 195                                         "an active setting\n");
 196
 197                                 ret = -EUSERS;
 198                                 goto exit;
 199                         }
 200                 }
 201         }
 202         update_registers(pmx, true);
 203         pmx->activated = true;
 204         dev_dbg(dev, "padmux: setting nr %d is activated\n",
 205                 pmx->setting);
 206
 207 exit:
 208         mutex_unlock(&pmx_mutex);
 209         return ret;
 210 }
 211 EXPORT_SYMBOL(pmx_activate);
 212
 213 int pmx_deactivate(struct device *dev, struct pmx *pmx)
 214 {
 215         int i;
 216         int ret = -ENOENT;
 217
 218         if (pmx == NULL || dev == NULL)
 219                 return -EINVAL;
 220
 221         mutex_lock(&pmx_mutex);
 222         for (i = 0; i < ARRAY_SIZE(pmx_settings); i++) {
 223
 224                 if (pmx_settings[i]->dev == NULL)
 225                         continue;
 226
 227                 if (pmx->setting == pmx_settings[i]->setting) {
 228
 229                         if (dev != pmx->dev) {
 230                                 WARN(1, "padmux: cannot deactivate "
 231                                      "pmx setting as it was activated "
 232                                      "by another consumer\n");
 233
 234                                 ret = -EBUSY;
 235                                 continue;
 236                         } else {
 237                                 update_registers(pmx, false);
 238                                 pmx_settings[i]->dev = NULL;
 239                                 pmx->activated = false;
 240                                 ret = 0;
 241                                 dev_dbg(dev, "padmux: setting nr %d is deactivated",
 242                                         pmx->setting);
 243                                 break;
 244                         }
 245                 }
 246         }
 247         mutex_unlock(&pmx_mutex);
 248
 249         return ret;
 250 }
 251 EXPORT_SYMBOL(pmx_deactivate);
 252
 253 /*
 254  * For internal use only. If it is to be exported,
 255  * it should be reentrant. Notice that pmx_activate
 256  * (i.e. runtime settings) always override default settings.
 257  */
 258 static int pmx_set_default(void)
 259 {
 260         /* Used to identify several entries on the same bits */
 261         u16 modbits[ARRAY_SIZE(pmx_registers)];
 262
 263         int i, j;
 264
 265         memset(modbits, 0, ARRAY_SIZE(pmx_registers) * sizeof(u16));
 266
 267         for (i = 0; i < ARRAY_SIZE(pmx_settings); i++) {
 268
 269                 if (!pmx_settings[i]->default_on)
 270                         continue;
 271
 272                 for (j = 0; j < ARRAY_SIZE(pmx_registers); j++) {
 273
 274                         /* Make sure there is only one entry on the same bits */
 275                         if (modbits[j] & pmx_settings[i]->onmask[j].mask) {
 276                                 BUG();
 277                                 return -EUSERS;
 278                         }
 279                         modbits[j] |= pmx_settings[i]->onmask[j].mask;
 280                 }
 281                 update_registers(pmx_settings[i], true);
 282         }
 283         return 0;
 284 }
 285
 286 #if (defined(CONFIG_DEBUG_FS) && defined(CONFIG_U300_DEBUG))
 287 static int pmx_show(struct seq_file *s, void *data)
 288 {
 289         int i;
 290         seq_printf(s, "-------------------------------------------------\n");
 291         seq_printf(s, "SETTING     BOUND TO DEVICE               STATE\n");
 292         seq_printf(s, "-------------------------------------------------\n");
 293         mutex_lock(&pmx_mutex);
 294         for (i = 0; i < ARRAY_SIZE(pmx_settings); i++) {
 295                 /* Format pmx and device name nicely */
 296                 char cdp[33];
 297                 int chars;
 298
 299                 chars = snprintf(&cdp[0], 17, "%s", pmx_settings[i]->name);
 300                 while (chars < 16) {
 301                         cdp[chars] = ' ';
 302                         chars++;
 303                 }
 304                 chars = snprintf(&cdp[16], 17, "%s", pmx_settings[i]->dev ?
 305                                 dev_name(pmx_settings[i]->dev) : "N/A");
 306                 while (chars < 16) {
 307                         cdp[chars+16] = ' ';
 308                         chars++;
 309                 }
 310                 cdp[32] = '\0';
 311
 312                 seq_printf(s,
 313                         "%s\t%s\n",
 314                         &cdp[0],
 315                         pmx_settings[i]->activated ?
 316                         "ACTIVATED" : "DEACTIVATED"
 317                         );
 318
 319         }
 320         mutex_unlock(&pmx_mutex);
 321         return 0;
 322 }
 323
 324 static int pmx_open(struct inode *inode, struct file *file)
 325 {
 326         return single_open(file, pmx_show, NULL);
 327 }
 328
 329 static const struct file_operations pmx_operations = {
 330         .owner          = THIS_MODULE,
 331         .open           = pmx_open,
 332         .read           = seq_read,
 333         .llseek         = seq_lseek,
 334         .release        = single_release,
 335 };
 336
 337 static int __init init_pmx_read_debugfs(void)
 338 {
 339         /* Expose a simple debugfs interface to view pmx settings */
 340         (void) debugfs_create_file("padmux", S_IFREG | S_IRUGO,
 341                                    NULL, NULL,
 342                                    &pmx_operations);
 343         return 0;
 344 }
 345
 346 /*
 347  * This needs to come in after the core_initcall(),
 348  * because debugfs is not available until
 349  * the subsystems come up.
 350  */
 351 module_init(init_pmx_read_debugfs);
 352 #endif
 353
 354 static int __init pmx_init(void)
 355 {
 356         int ret;
 357
 358         ret = pmx_set_default();
 359
 360         if (IS_ERR_VALUE(ret))
 361                 pr_crit("padmux: default settings could not be set\n");
 362
 363         return 0;
 364 }
 365
 366 /* Should be initialized before consumers */
 367 core_initcall(pmx_init);