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