arch/arm/mach-s3c/pm-gpio.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 //
   3 // Copyright 2008 Openmoko, Inc.
   4 // Copyright 2008 Simtec Electronics
   5 //      Ben Dooks <ben@simtec.co.uk>
   6 //      http://armlinux.simtec.co.uk/
   7 //
   8 // S3C series GPIO PM code
   9
  10 #include <linux/kernel.h>
  11 #include <linux/device.h>
  12 #include <linux/init.h>
  13 #include <linux/io.h>
  14 #include <linux/gpio.h>
  15
  16 #include "gpio-samsung.h"
  17
  18 #include "gpio-core.h"
  19 #include "pm.h"
  20
  21 /* PM GPIO helpers */
  22
  23 #define OFFS_CON        (0x00)
  24 #define OFFS_DAT        (0x04)
  25 #define OFFS_UP         (0x08)
  26
  27 static void samsung_gpio_pm_1bit_save(struct samsung_gpio_chip *chip)
  28 {
  29         chip->pm_save[0] = __raw_readl(chip->base + OFFS_CON);
  30         chip->pm_save[1] = __raw_readl(chip->base + OFFS_DAT);
  31 }
  32
  33 static void samsung_gpio_pm_1bit_resume(struct samsung_gpio_chip *chip)
  34 {
  35         void __iomem *base = chip->base;
  36         u32 old_gpcon = __raw_readl(base + OFFS_CON);
  37         u32 old_gpdat = __raw_readl(base + OFFS_DAT);
  38         u32 gps_gpcon = chip->pm_save[0];
  39         u32 gps_gpdat = chip->pm_save[1];
  40         u32 gpcon;
  41
  42         /* GPACON only has one bit per control / data and no PULLUPs.
  43          * GPACON[x] = 0 => Output, 1 => SFN */
  44
  45         /* first set all SFN bits to SFN */
  46
  47         gpcon = old_gpcon | gps_gpcon;
  48         __raw_writel(gpcon, base + OFFS_CON);
  49
  50         /* now set all the other bits */
  51
  52         __raw_writel(gps_gpdat, base + OFFS_DAT);
  53         __raw_writel(gps_gpcon, base + OFFS_CON);
  54
  55         S3C_PMDBG("%s: CON %08x => %08x, DAT %08x => %08x\n",
  56                   chip->chip.label, old_gpcon, gps_gpcon, old_gpdat, gps_gpdat);
  57 }
  58
  59 struct samsung_gpio_pm samsung_gpio_pm_1bit = {
  60         .save   = samsung_gpio_pm_1bit_save,
  61         .resume = samsung_gpio_pm_1bit_resume,
  62 };
  63
  64 static void samsung_gpio_pm_2bit_save(struct samsung_gpio_chip *chip)
  65 {
  66         chip->pm_save[0] = __raw_readl(chip->base + OFFS_CON);
  67         chip->pm_save[1] = __raw_readl(chip->base + OFFS_DAT);
  68         chip->pm_save[2] = __raw_readl(chip->base + OFFS_UP);
  69 }
  70
  71 /* Test whether the given masked+shifted bits of an GPIO configuration
  72  * are one of the SFN (special function) modes. */
  73
  74 static inline int is_sfn(unsigned long con)
  75 {
  76         return con >= 2;
  77 }
  78
  79 /* Test if the given masked+shifted GPIO configuration is an input */
  80
  81 static inline int is_in(unsigned long con)
  82 {
  83         return con == 0;
  84 }
  85
  86 /* Test if the given masked+shifted GPIO configuration is an output */
  87
  88 static inline int is_out(unsigned long con)
  89 {
  90         return con == 1;
  91 }
  92
  93 /**
  94  * samsung_gpio_pm_2bit_resume() - restore the given GPIO bank
  95  * @chip: The chip information to resume.
  96  *
  97  * Restore one of the GPIO banks that was saved during suspend. This is
  98  * not as simple as once thought, due to the possibility of glitches
  99  * from the order that the CON and DAT registers are set in.
 100  *
 101  * The three states the pin can be are {IN,OUT,SFN} which gives us 9
 102  * combinations of changes to check. Three of these, if the pin stays
 103  * in the same configuration can be discounted. This leaves us with
 104  * the following:
 105  *
 106  * { IN => OUT }  Change DAT first
 107  * { IN => SFN }  Change CON first
 108  * { OUT => SFN } Change CON first, so new data will not glitch
 109  * { OUT => IN }  Change CON first, so new data will not glitch
 110  * { SFN => IN }  Change CON first
 111  * { SFN => OUT } Change DAT first, so new data will not glitch [1]
 112  *
 113  * We do not currently deal with the UP registers as these control
 114  * weak resistors, so a small delay in change should not need to bring
 115  * these into the calculations.
 116  *
 117  * [1] this assumes that writing to a pin DAT whilst in SFN will set the
 118  *     state for when it is next output.
 119  */
 120 static void samsung_gpio_pm_2bit_resume(struct samsung_gpio_chip *chip)
 121 {
 122         void __iomem *base = chip->base;
 123         u32 old_gpcon = __raw_readl(base + OFFS_CON);
 124         u32 old_gpdat = __raw_readl(base + OFFS_DAT);
 125         u32 gps_gpcon = chip->pm_save[0];
 126         u32 gps_gpdat = chip->pm_save[1];
 127         u32 gpcon, old, new, mask;
 128         u32 change_mask = 0x0;
 129         int nr;
 130
 131         /* restore GPIO pull-up settings */
 132         __raw_writel(chip->pm_save[2], base + OFFS_UP);
 133
 134         /* Create a change_mask of all the items that need to have
 135          * their CON value changed before their DAT value, so that
 136          * we minimise the work between the two settings.
 137          */
 138
 139         for (nr = 0, mask = 0x03; nr < 32; nr += 2, mask <<= 2) {
 140                 old = (old_gpcon & mask) >> nr;
 141                 new = (gps_gpcon & mask) >> nr;
 142
 143                 /* If there is no change, then skip */
 144
 145                 if (old == new)
 146                         continue;
 147
 148                 /* If both are special function, then skip */
 149
 150                 if (is_sfn(old) && is_sfn(new))
 151                         continue;
 152
 153                 /* Change is IN => OUT, do not change now */
 154
 155                 if (is_in(old) && is_out(new))
 156                         continue;
 157
 158                 /* Change is SFN => OUT, do not change now */
 159
 160                 if (is_sfn(old) && is_out(new))
 161                         continue;
 162
 163                 /* We should now be at the case of IN=>SFN,
 164                  * OUT=>SFN, OUT=>IN, SFN=>IN. */
 165
 166                 change_mask |= mask;
 167         }
 168
 169
 170         /* Write the new CON settings */
 171
 172         gpcon = old_gpcon & ~change_mask;
 173         gpcon |= gps_gpcon & change_mask;
 174
 175         __raw_writel(gpcon, base + OFFS_CON);
 176
 177         /* Now change any items that require DAT,CON */
 178
 179         __raw_writel(gps_gpdat, base + OFFS_DAT);
 180         __raw_writel(gps_gpcon, base + OFFS_CON);
 181
 182         S3C_PMDBG("%s: CON %08x => %08x, DAT %08x => %08x\n",
 183                   chip->chip.label, old_gpcon, gps_gpcon, old_gpdat, gps_gpdat);
 184 }
 185
 186 struct samsung_gpio_pm samsung_gpio_pm_2bit = {
 187         .save   = samsung_gpio_pm_2bit_save,
 188         .resume = samsung_gpio_pm_2bit_resume,
 189 };
 190
 191 #if defined(CONFIG_ARCH_S3C64XX)
 192 static void samsung_gpio_pm_4bit_save(struct samsung_gpio_chip *chip)
 193 {
 194         chip->pm_save[1] = __raw_readl(chip->base + OFFS_CON);
 195         chip->pm_save[2] = __raw_readl(chip->base + OFFS_DAT);
 196         chip->pm_save[3] = __raw_readl(chip->base + OFFS_UP);
 197
 198         if (chip->chip.ngpio > 8)
 199                 chip->pm_save[0] = __raw_readl(chip->base - 4);
 200 }
 201
 202 static u32 samsung_gpio_pm_4bit_mask(u32 old_gpcon, u32 gps_gpcon)
 203 {
 204         u32 old, new, mask;
 205         u32 change_mask = 0x0;
 206         int nr;
 207
 208         for (nr = 0, mask = 0x0f; nr < 16; nr += 4, mask <<= 4) {
 209                 old = (old_gpcon & mask) >> nr;
 210                 new = (gps_gpcon & mask) >> nr;
 211
 212                 /* If there is no change, then skip */
 213
 214                 if (old == new)
 215                         continue;
 216
 217                 /* If both are special function, then skip */
 218
 219                 if (is_sfn(old) && is_sfn(new))
 220                         continue;
 221
 222                 /* Change is IN => OUT, do not change now */
 223
 224                 if (is_in(old) && is_out(new))
 225                         continue;
 226
 227                 /* Change is SFN => OUT, do not change now */
 228
 229                 if (is_sfn(old) && is_out(new))
 230                         continue;
 231
 232                 /* We should now be at the case of IN=>SFN,
 233                  * OUT=>SFN, OUT=>IN, SFN=>IN. */
 234
 235                 change_mask |= mask;
 236         }
 237
 238         return change_mask;
 239 }
 240
 241 static void samsung_gpio_pm_4bit_con(struct samsung_gpio_chip *chip, int index)
 242 {
 243         void __iomem *con = chip->base + (index * 4);
 244         u32 old_gpcon = __raw_readl(con);
 245         u32 gps_gpcon = chip->pm_save[index + 1];
 246         u32 gpcon, mask;
 247
 248         mask = samsung_gpio_pm_4bit_mask(old_gpcon, gps_gpcon);
 249
 250         gpcon = old_gpcon & ~mask;
 251         gpcon |= gps_gpcon & mask;
 252
 253         __raw_writel(gpcon, con);
 254 }
 255
 256 static void samsung_gpio_pm_4bit_resume(struct samsung_gpio_chip *chip)
 257 {
 258         void __iomem *base = chip->base;
 259         u32 old_gpcon[2];
 260         u32 old_gpdat = __raw_readl(base + OFFS_DAT);
 261         u32 gps_gpdat = chip->pm_save[2];
 262
 263         /* First, modify the CON settings */
 264
 265         old_gpcon[0] = 0;
 266         old_gpcon[1] = __raw_readl(base + OFFS_CON);
 267
 268         samsung_gpio_pm_4bit_con(chip, 0);
 269         if (chip->chip.ngpio > 8) {
 270                 old_gpcon[0] = __raw_readl(base - 4);
 271                 samsung_gpio_pm_4bit_con(chip, -1);
 272         }
 273
 274         /* Now change the configurations that require DAT,CON */
 275
 276         __raw_writel(chip->pm_save[2], base + OFFS_DAT);
 277         __raw_writel(chip->pm_save[1], base + OFFS_CON);
 278         if (chip->chip.ngpio > 8)
 279                 __raw_writel(chip->pm_save[0], base - 4);
 280
 281         __raw_writel(chip->pm_save[2], base + OFFS_DAT);
 282         __raw_writel(chip->pm_save[3], base + OFFS_UP);
 283
 284         if (chip->chip.ngpio > 8) {
 285                 S3C_PMDBG("%s: CON4 %08x,%08x => %08x,%08x, DAT %08x => %08x\n",
 286                           chip->chip.label, old_gpcon[0], old_gpcon[1],
 287                           __raw_readl(base - 4),
 288                           __raw_readl(base + OFFS_CON),
 289                           old_gpdat, gps_gpdat);
 290         } else
 291                 S3C_PMDBG("%s: CON4 %08x => %08x, DAT %08x => %08x\n",
 292                           chip->chip.label, old_gpcon[1],
 293                           __raw_readl(base + OFFS_CON),
 294                           old_gpdat, gps_gpdat);
 295 }
 296
 297 struct samsung_gpio_pm samsung_gpio_pm_4bit = {
 298         .save   = samsung_gpio_pm_4bit_save,
 299         .resume = samsung_gpio_pm_4bit_resume,
 300 };
 301 #endif /* CONFIG_ARCH_S3C64XX */
 302
 303 /**
 304  * samsung_pm_save_gpio() - save gpio chip data for suspend
 305  * @ourchip: The chip for suspend.
 306  */
 307 static void samsung_pm_save_gpio(struct samsung_gpio_chip *ourchip)
 308 {
 309         struct samsung_gpio_pm *pm = ourchip->pm;
 310
 311         if (pm == NULL || pm->save == NULL)
 312                 S3C_PMDBG("%s: no pm for %s\n", __func__, ourchip->chip.label);
 313         else
 314                 pm->save(ourchip);
 315 }
 316
 317 /**
 318  * samsung_pm_save_gpios() - Save the state of the GPIO banks.
 319  *
 320  * For all the GPIO banks, save the state of each one ready for going
 321  * into a suspend mode.
 322  */
 323 void samsung_pm_save_gpios(void)
 324 {
 325         struct samsung_gpio_chip *ourchip;
 326         unsigned int gpio_nr;
 327
 328         for (gpio_nr = 0; gpio_nr < S3C_GPIO_END;) {
 329                 ourchip = samsung_gpiolib_getchip(gpio_nr);
 330                 if (!ourchip) {
 331                         gpio_nr++;
 332                         continue;
 333                 }
 334
 335                 samsung_pm_save_gpio(ourchip);
 336
 337                 S3C_PMDBG("%s: save %08x,%08x,%08x,%08x\n",
 338                           ourchip->chip.label,
 339                           ourchip->pm_save[0],
 340                           ourchip->pm_save[1],
 341                           ourchip->pm_save[2],
 342                           ourchip->pm_save[3]);
 343
 344                 gpio_nr += ourchip->chip.ngpio;
 345                 gpio_nr += CONFIG_S3C_GPIO_SPACE;
 346         }
 347 }
 348
 349 /**
 350  * samsung_pm_resume_gpio() - restore gpio chip data after suspend
 351  * @ourchip: The suspended chip.
 352  */
 353 static void samsung_pm_resume_gpio(struct samsung_gpio_chip *ourchip)
 354 {
 355         struct samsung_gpio_pm *pm = ourchip->pm;
 356
 357         if (pm == NULL || pm->resume == NULL)
 358                 S3C_PMDBG("%s: no pm for %s\n", __func__, ourchip->chip.label);
 359         else
 360                 pm->resume(ourchip);
 361 }
 362
 363 void samsung_pm_restore_gpios(void)
 364 {
 365         struct samsung_gpio_chip *ourchip;
 366         unsigned int gpio_nr;
 367
 368         for (gpio_nr = 0; gpio_nr < S3C_GPIO_END;) {
 369                 ourchip = samsung_gpiolib_getchip(gpio_nr);
 370                 if (!ourchip) {
 371                         gpio_nr++;
 372                         continue;
 373                 }
 374
 375                 samsung_pm_resume_gpio(ourchip);
 376
 377                 gpio_nr += ourchip->chip.ngpio;
 378                 gpio_nr += CONFIG_S3C_GPIO_SPACE;
 379         }
 380 }