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
samsung_gpio_pm_1bit_save(struct samsung_gpio_chip * chip)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
samsung_gpio_pm_1bit_resume(struct samsung_gpio_chip * chip)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
samsung_gpio_pm_2bit_save(struct samsung_gpio_chip * chip)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
is_sfn(unsigned long con)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
is_in(unsigned long con)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
is_out(unsigned long con)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 */
samsung_gpio_pm_2bit_resume(struct samsung_gpio_chip * chip)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)
samsung_gpio_pm_4bit_save(struct samsung_gpio_chip * chip)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
samsung_gpio_pm_4bit_mask(u32 old_gpcon,u32 gps_gpcon)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
samsung_gpio_pm_4bit_con(struct samsung_gpio_chip * chip,int index)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
samsung_gpio_pm_4bit_resume(struct samsung_gpio_chip * chip)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 */
samsung_pm_save_gpio(struct samsung_gpio_chip * ourchip)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 */
samsung_pm_save_gpios(void)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 */
samsung_pm_resume_gpio(struct samsung_gpio_chip * ourchip)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
samsung_pm_restore_gpios(void)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