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

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  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 }
387 

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