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
samsung_gpio_pm_1bit_save(struct samsung_gpio_chip * chip)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
samsung_gpio_pm_1bit_resume(struct samsung_gpio_chip * chip)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
samsung_gpio_pm_2bit_save(struct samsung_gpio_chip * chip)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
is_sfn(unsigned long con)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
is_in(unsigned long con)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
is_out(unsigned long con)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 */
samsung_gpio_pm_2bit_resume(struct samsung_gpio_chip * chip)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)
samsung_gpio_pm_4bit_save(struct samsung_gpio_chip * chip)196 static void samsung_gpio_pm_4bit_save(struct samsung_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
samsung_gpio_pm_4bit_mask(u32 old_gpcon,u32 gps_gpcon)206 static u32 samsung_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
samsung_gpio_pm_4bit_con(struct samsung_gpio_chip * chip,int index)245 static void samsung_gpio_pm_4bit_con(struct samsung_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 = samsung_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
samsung_gpio_pm_4bit_resume(struct samsung_gpio_chip * chip)260 static void samsung_gpio_pm_4bit_resume(struct samsung_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 samsung_gpio_pm_4bit_con(chip, 0);
273 if (chip->chip.ngpio > 8) {
274 old_gpcon[0] = __raw_readl(base - 4);
275 samsung_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 samsung_gpio_pm samsung_gpio_pm_4bit = {
302 .save = samsung_gpio_pm_4bit_save,
303 .resume = samsung_gpio_pm_4bit_resume,
304 };
305 #endif /* CONFIG_ARCH_S3C64XX || CONFIG_PLAT_S5P */
306
307 /**
308 * samsung_pm_save_gpio() - save gpio chip data for suspend
309 * @ourchip: The chip for suspend.
310 */
samsung_pm_save_gpio(struct samsung_gpio_chip * ourchip)311 static void samsung_pm_save_gpio(struct samsung_gpio_chip *ourchip)
312 {
313 struct samsung_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 * samsung_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 */
samsung_pm_save_gpios(void)327 void samsung_pm_save_gpios(void)
328 {
329 struct samsung_gpio_chip *ourchip;
330 unsigned int gpio_nr;
331
332 for (gpio_nr = 0; gpio_nr < S3C_GPIO_END;) {
333 ourchip = samsung_gpiolib_getchip(gpio_nr);
334 if (!ourchip) {
335 gpio_nr++;
336 continue;
337 }
338
339 samsung_pm_save_gpio(ourchip);
340
341 S3C_PMDBG("%s: save %08x,%08x,%08x,%08x\n",
342 ourchip->chip.label,
343 ourchip->pm_save[0],
344 ourchip->pm_save[1],
345 ourchip->pm_save[2],
346 ourchip->pm_save[3]);
347
348 gpio_nr += ourchip->chip.ngpio;
349 gpio_nr += CONFIG_S3C_GPIO_SPACE;
350 }
351 }
352
353 /**
354 * samsung_pm_resume_gpio() - restore gpio chip data after suspend
355 * @ourchip: The suspended chip.
356 */
samsung_pm_resume_gpio(struct samsung_gpio_chip * ourchip)357 static void samsung_pm_resume_gpio(struct samsung_gpio_chip *ourchip)
358 {
359 struct samsung_gpio_pm *pm = ourchip->pm;
360
361 if (pm == NULL || pm->resume == NULL)
362 S3C_PMDBG("%s: no pm for %s\n", __func__, ourchip->chip.label);
363 else
364 pm->resume(ourchip);
365 }
366
samsung_pm_restore_gpios(void)367 void samsung_pm_restore_gpios(void)
368 {
369 struct samsung_gpio_chip *ourchip;
370 unsigned int gpio_nr;
371
372 for (gpio_nr = 0; gpio_nr < S3C_GPIO_END;) {
373 ourchip = samsung_gpiolib_getchip(gpio_nr);
374 if (!ourchip) {
375 gpio_nr++;
376 continue;
377 }
378
379 samsung_pm_resume_gpio(ourchip);
380
381 gpio_nr += ourchip->chip.ngpio;
382 gpio_nr += CONFIG_S3C_GPIO_SPACE;
383 }
384 }
385