arch/arm/plat-s3c/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/sysdev.h>
  18 #include <linux/init.h>
  19 #include <linux/io.h>
  20 #include <linux/gpio.h>
  21
  22 #include <mach/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 s3c_gpio_pm_1bit_save(struct s3c_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 s3c_gpio_pm_1bit_resume(struct s3c_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 s3c_gpio_pm s3c_gpio_pm_1bit = {
  64         .save   = s3c_gpio_pm_1bit_save,
  65         .resume = s3c_gpio_pm_1bit_resume,
  66 };
  67
  68 static void s3c_gpio_pm_2bit_save(struct s3c_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  * s3c_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 s3c_gpio_pm_2bit_resume(struct s3c_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 s3c_gpio_pm s3c_gpio_pm_2bit = {
 191         .save   = s3c_gpio_pm_2bit_save,
 192         .resume = s3c_gpio_pm_2bit_resume,
 193 };
 194
 195 #ifdef CONFIG_ARCH_S3C64XX
 196 static void s3c_gpio_pm_4bit_save(struct s3c_gpio_chip *chip)
 197 {
 198         chip->pm_save[1] = __raw_readl(chip->base + OFFS_CON);
 199         chip->pm_save[2] = __raw_readl(chip->base + OFFS_DAT);
 200         chip->pm_save[3] = __raw_readl(chip->base + OFFS_UP);
 201
 202         if (chip->chip.ngpio > 8)
 203                 chip->pm_save[0] = __raw_readl(chip->base - 4);
 204 }
 205
 206 static u32 s3c_gpio_pm_4bit_mask(u32 old_gpcon, u32 gps_gpcon)
 207 {
 208         u32 old, new, mask;
 209         u32 change_mask = 0x0;
 210         int nr;
 211
 212         for (nr = 0, mask = 0x0f; nr < 16; nr += 4, mask <<= 4) {
 213                 old = (old_gpcon & mask) >> nr;
 214                 new = (gps_gpcon & mask) >> nr;
 215
 216                 /* If there is no change, then skip */
 217
 218                 if (old == new)
 219                         continue;
 220
 221                 /* If both are special function, then skip */
 222
 223                 if (is_sfn(old) && is_sfn(new))
 224                         continue;
 225
 226                 /* Change is IN => OUT, do not change now */
 227
 228                 if (is_in(old) && is_out(new))
 229                         continue;
 230
 231                 /* Change is SFN => OUT, do not change now */
 232
 233                 if (is_sfn(old) && is_out(new))
 234                         continue;
 235
 236                 /* We should now be at the case of IN=>SFN,
 237                  * OUT=>SFN, OUT=>IN, SFN=>IN. */
 238
 239                 change_mask |= mask;
 240         }
 241
 242         return change_mask;
 243 }
 244
 245 static void s3c_gpio_pm_4bit_con(struct s3c_gpio_chip *chip, int index)
 246 {
 247         void __iomem *con = chip->base + (index * 4);
 248         u32 old_gpcon = __raw_readl(con);
 249         u32 gps_gpcon = chip->pm_save[index + 1];
 250         u32 gpcon, mask;
 251
 252         mask = s3c_gpio_pm_4bit_mask(old_gpcon, gps_gpcon);
 253
 254         gpcon = old_gpcon & ~mask;
 255         gpcon |= gps_gpcon & mask;
 256
 257         __raw_writel(gpcon, con);
 258 }
 259
 260 static void s3c_gpio_pm_4bit_resume(struct s3c_gpio_chip *chip)
 261 {
 262         void __iomem *base = chip->base;
 263         u32 old_gpcon[2];
 264         u32 old_gpdat = __raw_readl(base + OFFS_DAT);
 265         u32 gps_gpdat = chip->pm_save[2];
 266
 267         /* First, modify the CON settings */
 268
 269         old_gpcon[0] = 0;
 270         old_gpcon[1] = __raw_readl(base + OFFS_CON);
 271
 272         s3c_gpio_pm_4bit_con(chip, 0);
 273         if (chip->chip.ngpio > 8) {
 274                 old_gpcon[0] = __raw_readl(base - 4);
 275                 s3c_gpio_pm_4bit_con(chip, -1);
 276         }
 277
 278         /* Now change the configurations that require DAT,CON */
 279
 280         __raw_writel(chip->pm_save[2], base + OFFS_DAT);
 281         __raw_writel(chip->pm_save[1], base + OFFS_CON);
 282         if (chip->chip.ngpio > 8)
 283                 __raw_writel(chip->pm_save[0], base - 4);
 284
 285         __raw_writel(chip->pm_save[2], base + OFFS_DAT);
 286         __raw_writel(chip->pm_save[3], base + OFFS_UP);
 287
 288         if (chip->chip.ngpio > 8) {
 289                 S3C_PMDBG("%s: CON4 %08x,%08x => %08x,%08x, DAT %08x => %08x\n",
 290                           chip->chip.label, old_gpcon[0], old_gpcon[1],
 291                           __raw_readl(base - 4),
 292                           __raw_readl(base + OFFS_CON),
 293                           old_gpdat, gps_gpdat);
 294         } else
 295                 S3C_PMDBG("%s: CON4 %08x => %08x, DAT %08x => %08x\n",
 296                           chip->chip.label, old_gpcon[1],
 297                           __raw_readl(base + OFFS_CON),
 298                           old_gpdat, gps_gpdat);
 299 }
 300
 301 struct s3c_gpio_pm s3c_gpio_pm_4bit = {
 302         .save   = s3c_gpio_pm_4bit_save,
 303         .resume = s3c_gpio_pm_4bit_resume,
 304 };
 305 #endif /* CONFIG_ARCH_S3C64XX */
 306
 307 /**
 308  * s3c_pm_save_gpio() - save gpio chip data for suspend
 309  * @ourchip: The chip for suspend.
 310  */
 311 static void s3c_pm_save_gpio(struct s3c_gpio_chip *ourchip)
 312 {
 313         struct s3c_gpio_pm *pm = ourchip->pm;
 314
 315         if (pm == NULL || pm->save == NULL)
 316                 S3C_PMDBG("%s: no pm for %s\n", __func__, ourchip->chip.label);
 317         else
 318                 pm->save(ourchip);
 319 }
 320
 321 /**
 322  * s3c_pm_save_gpios() - Save the state of the GPIO banks.
 323  *
 324  * For all the GPIO banks, save the state of each one ready for going
 325  * into a suspend mode.
 326  */
 327 void s3c_pm_save_gpios(void)
 328 {
 329         struct s3c_gpio_chip *ourchip;
 330         unsigned int gpio_nr;
 331
 332         for (gpio_nr = 0; gpio_nr < S3C_GPIO_END; gpio_nr++) {
 333                 ourchip = s3c_gpiolib_getchip(gpio_nr);
 334                 if (!ourchip)
 335                         continue;
 336
 337                 s3c_pm_save_gpio(ourchip);
 338
 339                 S3C_PMDBG("%s: save %08x,%08x,%08x,%08x\n",
 340                           ourchip->chip.label,
 341                           ourchip->pm_save[0],
 342                           ourchip->pm_save[1],
 343                           ourchip->pm_save[2],
 344                           ourchip->pm_save[3]);
 345
 346                 gpio_nr += ourchip->chip.ngpio;
 347                 gpio_nr += CONFIG_S3C_GPIO_SPACE;
 348         }
 349 }
 350
 351 /**
 352  * s3c_pm_resume_gpio() - restore gpio chip data after suspend
 353  * @ourchip: The suspended chip.
 354  */
 355 static void s3c_pm_resume_gpio(struct s3c_gpio_chip *ourchip)
 356 {
 357         struct s3c_gpio_pm *pm = ourchip->pm;
 358
 359         if (pm == NULL || pm->resume == NULL)
 360                 S3C_PMDBG("%s: no pm for %s\n", __func__, ourchip->chip.label);
 361         else
 362                 pm->resume(ourchip);
 363 }
 364
 365 void s3c_pm_restore_gpios(void)
 366 {
 367         struct s3c_gpio_chip *ourchip;
 368         unsigned int gpio_nr;
 369
 370         for (gpio_nr = 0; gpio_nr < S3C_GPIO_END; gpio_nr++) {
 371                 ourchip = s3c_gpiolib_getchip(gpio_nr);
 372                 if (!ourchip)
 373                         continue;
 374
 375                 s3c_pm_resume_gpio(ourchip);
 376
 377                 gpio_nr += ourchip->chip.ngpio;
 378                 gpio_nr += CONFIG_S3C_GPIO_SPACE;
 379         }
 380 }