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