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
33static 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
39static 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
65struct samsung_gpio_pm samsung_gpio_pm_1bit = {
66	.save	= samsung_gpio_pm_1bit_save,
67	.resume = samsung_gpio_pm_1bit_resume,
68};
69
70static 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
80static 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
87static 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
94static 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 */
126static 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
192struct 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)
198static 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
208static 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
247static 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
262static 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
303struct 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 */
313static 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 */
329void 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 */
359static 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
369void 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