arch/arm/plat-samsung/pm-gpio.c

   1
   2 /* linux/arch/arm/plat-s3c/pm-gpio.c
   3  *
   4  * Copyright 2008 Openmoko, Inc.
   5  * Copyright 2008 Simtec Electronics
   6  *      Ben Dooks <ben@simtec.co.uk>
   7  *      http://armlinux.simtec.co.uk/
   8  *
   9  * S3C series GPIO PM code
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License version 2 as
  13  * published by the Free Software Foundation.
  14 */
  15
  16 #include <linux/kernel.h>
  17 #include <linux/device.h>
  18 #include <linux/init.h>
  19 #include <linux/io.h>
  20 #include <linux/gpio.h>
  21
  22 #if defined(CONFIG_ARCH_S3C24XX) || defined(CONFIG_ARCH_S3C64XX)
  23 #include <mach/gpio-samsung.h>
  24 #endif
  25
  26 #include <plat/gpio-core.h>
  27 #include <plat/pm.h>
  28
  29 /* PM GPIO helpers */
  30
  31 #define OFFS_CON        (0x00)
  32 #define OFFS_DAT        (0x04)
  33 #define OFFS_UP         (0x08)
  34
  35 static void samsung_gpio_pm_1bit_save(struct samsung_gpio_chip *chip)
  36 {
  37         chip->pm_save[0] = __raw_readl(chip->base + OFFS_CON);
  38         chip->pm_save[1] = __raw_readl(chip->base + OFFS_DAT);
  39 }
  40
  41 static void samsung_gpio_pm_1bit_resume(struct samsung_gpio_chip *chip)
  42 {
  43         void __iomem *base = chip->base;
  44         u32 old_gpcon = __raw_readl(base + OFFS_CON);
  45         u32 old_gpdat = __raw_readl(base + OFFS_DAT);
  46         u32 gps_gpcon = chip->pm_save[0];
  47         u32 gps_gpdat = chip->pm_save[1];
  48         u32 gpcon;
  49
  50         /* GPACON only has one bit per control / data and no PULLUPs.
  51          * GPACON[x] = 0 => Output, 1 => SFN */
  52
  53         /* first set all SFN bits to SFN */
  54
  55         gpcon = old_gpcon | gps_gpcon;
  56         __raw_writel(gpcon, base + OFFS_CON);
  57
  58         /* now set all the other bits */
  59
  60         __raw_writel(gps_gpdat, base + OFFS_DAT);
  61         __raw_writel(gps_gpcon, base + OFFS_CON);
  62
  63         S3C_PMDBG("%s: CON %08x => %08x, DAT %08x => %08x\n",
  64                   chip->chip.label, old_gpcon, gps_gpcon, old_gpdat, gps_gpdat);
  65 }
  66
  67 struct samsung_gpio_pm samsung_gpio_pm_1bit = {
  68         .save   = samsung_gpio_pm_1bit_save,
  69         .resume = samsung_gpio_pm_1bit_resume,
  70 };
  71
  72 static void samsung_gpio_pm_2bit_save(struct samsung_gpio_chip *chip)
  73 {
  74         chip->pm_save[0] = __raw_readl(chip->base + OFFS_CON);
  75         chip->pm_save[1] = __raw_readl(chip->base + OFFS_DAT);
  76         chip->pm_save[2] = __raw_readl(chip->base + OFFS_UP);
  77 }
  78
  79 /* Test whether the given masked+shifted bits of an GPIO configuration
  80  * are one of the SFN (special function) modes. */
  81
  82 static inline int is_sfn(unsigned long con)
  83 {
  84         return con >= 2;
  85 }
  86
  87 /* Test if the given masked+shifted GPIO configuration is an input */
  88
  89 static inline int is_in(unsigned long con)
  90 {
  91         return con == 0;
  92 }
  93
  94 /* Test if the given masked+shifted GPIO configuration is an output */
  95
  96 static inline int is_out(unsigned long con)
  97 {
  98         return con == 1;
  99 }
 100
 101 /**
 102  * samsung_gpio_pm_2bit_resume() - restore the given GPIO bank
 103  * @chip: The chip information to resume.
 104  *
 105  * Restore one of the GPIO banks that was saved during suspend. This is
 106  * not as simple as once thought, due to the possibility of glitches
 107  * from the order that the CON and DAT registers are set in.
 108  *
 109  * The three states the pin can be are {IN,OUT,SFN} which gives us 9
 110  * combinations of changes to check. Three of these, if the pin stays
 111  * in the same configuration can be discounted. This leaves us with
 112  * the following:
 113  *
 114  * { IN => OUT }  Change DAT first
 115  * { IN => SFN }  Change CON first
 116  * { OUT => SFN } Change CON first, so new data will not glitch
 117  * { OUT => IN }  Change CON first, so new data will not glitch
 118  * { SFN => IN }  Change CON first
 119  * { SFN => OUT } Change DAT first, so new data will not glitch [1]
 120  *
 121  * We do not currently deal with the UP registers as these control
 122  * weak resistors, so a small delay in change should not need to bring
 123  * these into the calculations.
 124  *
 125  * [1] this assumes that writing to a pin DAT whilst in SFN will set the
 126  *     state for when it is next output.
 127  */
 128 static void samsung_gpio_pm_2bit_resume(struct samsung_gpio_chip *chip)
 129 {
 130         void __iomem *base = chip->base;
 131         u32 old_gpcon = __raw_readl(base + OFFS_CON);
 132         u32 old_gpdat = __raw_readl(base + OFFS_DAT);
 133         u32 gps_gpcon = chip->pm_save[0];
 134         u32 gps_gpdat = chip->pm_save[1];
 135         u32 gpcon, old, new, mask;
 136         u32 change_mask = 0x0;
 137         int nr;
 138
 139         /* restore GPIO pull-up settings */
 140         __raw_writel(chip->pm_save[2], base + OFFS_UP);
 141
 142         /* Create a change_mask of all the items that need to have
 143          * their CON value changed before their DAT value, so that
 144          * we minimise the work between the two settings.
 145          */
 146
 147         for (nr = 0, mask = 0x03; nr < 32; nr += 2, mask <<= 2) {
 148                 old = (old_gpcon & mask) >> nr;
 149                 new = (gps_gpcon & mask) >> nr;
 150
 151                 /* If there is no change, then skip */
 152
 153                 if (old == new)
 154                         continue;
 155
 156                 /* If both are special function, then skip */
 157
 158                 if (is_sfn(old) && is_sfn(new))
 159                         continue;
 160
 161                 /* Change is IN => OUT, do not change now */
 162
 163                 if (is_in(old) && is_out(new))
 164                         continue;
 165
 166                 /* Change is SFN => OUT, do not change now */
 167
 168                 if (is_sfn(old) && is_out(new))
 169                         continue;
 170
 171                 /* We should now be at the case of IN=>SFN,
 172                  * OUT=>SFN, OUT=>IN, SFN=>IN. */
 173
 174                 change_mask |= mask;
 175         }
 176
 177
 178         /* Write the new CON settings */
 179
 180         gpcon = old_gpcon & ~change_mask;
 181         gpcon |= gps_gpcon & change_mask;
 182
 183         __raw_writel(gpcon, base + OFFS_CON);
 184
 185         /* Now change any items that require DAT,CON */
 186
 187         __raw_writel(gps_gpdat, base + OFFS_DAT);
 188         __raw_writel(gps_gpcon, base + OFFS_CON);
 189
 190         S3C_PMDBG("%s: CON %08x => %08x, DAT %08x => %08x\n",
 191                   chip->chip.label, old_gpcon, gps_gpcon, old_gpdat, gps_gpdat);
 192 }
 193
 194 struct samsung_gpio_pm samsung_gpio_pm_2bit = {
 195         .save   = samsung_gpio_pm_2bit_save,
 196         .resume = samsung_gpio_pm_2bit_resume,
 197 };
 198
 199 #if defined(CONFIG_ARCH_S3C64XX) || defined(CONFIG_PLAT_S5P) \
 200         || defined(CONFIG_ARCH_EXYNOS)
 201 static void samsung_gpio_pm_4bit_save(struct samsung_gpio_chip *chip)
 202 {
 203         chip->pm_save[1] = __raw_readl(chip->base + OFFS_CON);
 204         chip->pm_save[2] = __raw_readl(chip->base + OFFS_DAT);
 205         chip->pm_save[3] = __raw_readl(chip->base + OFFS_UP);
 206
 207         if (chip->chip.ngpio > 8)
 208                 chip->pm_save[0] = __raw_readl(chip->base - 4);
 209 }
 210
 211 static u32 samsung_gpio_pm_4bit_mask(u32 old_gpcon, u32 gps_gpcon)
 212 {
 213         u32 old, new, mask;
 214         u32 change_mask = 0x0;
 215         int nr;
 216
 217         for (nr = 0, mask = 0x0f; nr < 16; nr += 4, mask <<= 4) {
 218                 old = (old_gpcon & mask) >> nr;
 219                 new = (gps_gpcon & mask) >> nr;
 220
 221                 /* If there is no change, then skip */
 222
 223                 if (old == new)
 224                         continue;
 225
 226                 /* If both are special function, then skip */
 227
 228                 if (is_sfn(old) && is_sfn(new))
 229                         continue;
 230
 231                 /* Change is IN => OUT, do not change now */
 232
 233                 if (is_in(old) && is_out(new))
 234                         continue;
 235
 236                 /* Change is SFN => OUT, do not change now */
 237
 238                 if (is_sfn(old) && is_out(new))
 239                         continue;
 240
 241                 /* We should now be at the case of IN=>SFN,
 242                  * OUT=>SFN, OUT=>IN, SFN=>IN. */
 243
 244                 change_mask |= mask;
 245         }
 246
 247         return change_mask;
 248 }
 249
 250 static void samsung_gpio_pm_4bit_con(struct samsung_gpio_chip *chip, int index)
 251 {
 252         void __iomem *con = chip->base + (index * 4);
 253         u32 old_gpcon = __raw_readl(con);
 254         u32 gps_gpcon = chip->pm_save[index + 1];
 255         u32 gpcon, mask;
 256
 257         mask = samsung_gpio_pm_4bit_mask(old_gpcon, gps_gpcon);
 258
 259         gpcon = old_gpcon & ~mask;
 260         gpcon |= gps_gpcon & mask;
 261
 262         __raw_writel(gpcon, con);
 263 }
 264
 265 static void samsung_gpio_pm_4bit_resume(struct samsung_gpio_chip *chip)
 266 {
 267         void __iomem *base = chip->base;
 268         u32 old_gpcon[2];
 269         u32 old_gpdat = __raw_readl(base + OFFS_DAT);
 270         u32 gps_gpdat = chip->pm_save[2];
 271
 272         /* First, modify the CON settings */
 273
 274         old_gpcon[0] = 0;
 275         old_gpcon[1] = __raw_readl(base + OFFS_CON);
 276
 277         samsung_gpio_pm_4bit_con(chip, 0);
 278         if (chip->chip.ngpio > 8) {
 279                 old_gpcon[0] = __raw_readl(base - 4);
 280                 samsung_gpio_pm_4bit_con(chip, -1);
 281         }
 282
 283         /* Now change the configurations that require DAT,CON */
 284
 285         __raw_writel(chip->pm_save[2], base + OFFS_DAT);
 286         __raw_writel(chip->pm_save[1], base + OFFS_CON);
 287         if (chip->chip.ngpio > 8)
 288                 __raw_writel(chip->pm_save[0], base - 4);
 289
 290         __raw_writel(chip->pm_save[2], base + OFFS_DAT);
 291         __raw_writel(chip->pm_save[3], base + OFFS_UP);
 292
 293         if (chip->chip.ngpio > 8) {
 294                 S3C_PMDBG("%s: CON4 %08x,%08x => %08x,%08x, DAT %08x => %08x\n",
 295                           chip->chip.label, old_gpcon[0], old_gpcon[1],
 296                           __raw_readl(base - 4),
 297                           __raw_readl(base + OFFS_CON),
 298                           old_gpdat, gps_gpdat);
 299         } else
 300                 S3C_PMDBG("%s: CON4 %08x => %08x, DAT %08x => %08x\n",
 301                           chip->chip.label, old_gpcon[1],
 302                           __raw_readl(base + OFFS_CON),
 303                           old_gpdat, gps_gpdat);
 304 }
 305
 306 struct samsung_gpio_pm samsung_gpio_pm_4bit = {
 307         .save   = samsung_gpio_pm_4bit_save,
 308         .resume = samsung_gpio_pm_4bit_resume,
 309 };
 310 #endif /* CONFIG_ARCH_S3C64XX || CONFIG_PLAT_S5P || CONFIG_ARCH_EXYNOS */
 311
 312 /**
 313  * samsung_pm_save_gpio() - save gpio chip data for suspend
 314  * @ourchip: The chip for suspend.
 315  */
 316 static void samsung_pm_save_gpio(struct samsung_gpio_chip *ourchip)
 317 {
 318         struct samsung_gpio_pm *pm = ourchip->pm;
 319
 320         if (pm == NULL || pm->save == NULL)
 321                 S3C_PMDBG("%s: no pm for %s\n", __func__, ourchip->chip.label);
 322         else
 323                 pm->save(ourchip);
 324 }
 325
 326 /**
 327  * samsung_pm_save_gpios() - Save the state of the GPIO banks.
 328  *
 329  * For all the GPIO banks, save the state of each one ready for going
 330  * into a suspend mode.
 331  */
 332 void samsung_pm_save_gpios(void)
 333 {
 334         struct samsung_gpio_chip *ourchip;
 335         unsigned int gpio_nr;
 336
 337         for (gpio_nr = 0; gpio_nr < S3C_GPIO_END;) {
 338                 ourchip = samsung_gpiolib_getchip(gpio_nr);
 339                 if (!ourchip) {
 340                         gpio_nr++;
 341                         continue;
 342                 }
 343
 344                 samsung_pm_save_gpio(ourchip);
 345
 346                 S3C_PMDBG("%s: save %08x,%08x,%08x,%08x\n",
 347                           ourchip->chip.label,
 348                           ourchip->pm_save[0],
 349                           ourchip->pm_save[1],
 350                           ourchip->pm_save[2],
 351                           ourchip->pm_save[3]);
 352
 353                 gpio_nr += ourchip->chip.ngpio;
 354                 gpio_nr += CONFIG_S3C_GPIO_SPACE;
 355         }
 356 }
 357
 358 /**
 359  * samsung_pm_resume_gpio() - restore gpio chip data after suspend
 360  * @ourchip: The suspended chip.
 361  */
 362 static void samsung_pm_resume_gpio(struct samsung_gpio_chip *ourchip)
 363 {
 364         struct samsung_gpio_pm *pm = ourchip->pm;
 365
 366         if (pm == NULL || pm->resume == NULL)
 367                 S3C_PMDBG("%s: no pm for %s\n", __func__, ourchip->chip.label);
 368         else
 369                 pm->resume(ourchip);
 370 }
 371
 372 void samsung_pm_restore_gpios(void)
 373 {
 374         struct samsung_gpio_chip *ourchip;
 375         unsigned int gpio_nr;
 376
 377         for (gpio_nr = 0; gpio_nr < S3C_GPIO_END;) {
 378                 ourchip = samsung_gpiolib_getchip(gpio_nr);
 379                 if (!ourchip) {
 380                         gpio_nr++;
 381                         continue;
 382                 }
 383
 384                 samsung_pm_resume_gpio(ourchip);
 385
 386                 gpio_nr += ourchip->chip.ngpio;
 387                 gpio_nr += CONFIG_S3C_GPIO_SPACE;
 388         }
 389 }