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