1// SPDX-License-Identifier: GPL-2.0+
2//
3// Copyright 2008 Openmoko, Inc.
4// Copyright 2008 Simtec Electronics
5//	Ben Dooks <ben@simtec.co.uk>
6//	http://armlinux.simtec.co.uk/
7//
8// S3C series GPIO PM code
9
10#include <linux/kernel.h>
11#include <linux/device.h>
12#include <linux/init.h>
13#include <linux/io.h>
14#include <linux/gpio.h>
15
16#include "gpio-samsung.h"
17
18#include "gpio-core.h"
19#include "pm.h"
20
21/* PM GPIO helpers */
22
23#define OFFS_CON	(0x00)
24#define OFFS_DAT	(0x04)
25#define OFFS_UP		(0x08)
26
27static void samsung_gpio_pm_1bit_save(struct samsung_gpio_chip *chip)
28{
29	chip->pm_save[0] = __raw_readl(chip->base + OFFS_CON);
30	chip->pm_save[1] = __raw_readl(chip->base + OFFS_DAT);
31}
32
33static void samsung_gpio_pm_1bit_resume(struct samsung_gpio_chip *chip)
34{
35	void __iomem *base = chip->base;
36	u32 old_gpcon = __raw_readl(base + OFFS_CON);
37	u32 old_gpdat = __raw_readl(base + OFFS_DAT);
38	u32 gps_gpcon = chip->pm_save[0];
39	u32 gps_gpdat = chip->pm_save[1];
40	u32 gpcon;
41
42	/* GPACON only has one bit per control / data and no PULLUPs.
43	 * GPACON[x] = 0 => Output, 1 => SFN */
44
45	/* first set all SFN bits to SFN */
46
47	gpcon = old_gpcon | gps_gpcon;
48	__raw_writel(gpcon, base + OFFS_CON);
49
50	/* now set all the other bits */
51
52	__raw_writel(gps_gpdat, base + OFFS_DAT);
53	__raw_writel(gps_gpcon, base + OFFS_CON);
54
55	S3C_PMDBG("%s: CON %08x => %08x, DAT %08x => %08x\n",
56		  chip->chip.label, old_gpcon, gps_gpcon, old_gpdat, gps_gpdat);
57}
58
59struct samsung_gpio_pm samsung_gpio_pm_1bit = {
60	.save	= samsung_gpio_pm_1bit_save,
61	.resume = samsung_gpio_pm_1bit_resume,
62};
63
64static void samsung_gpio_pm_2bit_save(struct samsung_gpio_chip *chip)
65{
66	chip->pm_save[0] = __raw_readl(chip->base + OFFS_CON);
67	chip->pm_save[1] = __raw_readl(chip->base + OFFS_DAT);
68	chip->pm_save[2] = __raw_readl(chip->base + OFFS_UP);
69}
70
71/* Test whether the given masked+shifted bits of an GPIO configuration
72 * are one of the SFN (special function) modes. */
73
74static inline int is_sfn(unsigned long con)
75{
76	return con >= 2;
77}
78
79/* Test if the given masked+shifted GPIO configuration is an input */
80
81static inline int is_in(unsigned long con)
82{
83	return con == 0;
84}
85
86/* Test if the given masked+shifted GPIO configuration is an output */
87
88static inline int is_out(unsigned long con)
89{
90	return con == 1;
91}
92
93/**
94 * samsung_gpio_pm_2bit_resume() - restore the given GPIO bank
95 * @chip: The chip information to resume.
96 *
97 * Restore one of the GPIO banks that was saved during suspend. This is
98 * not as simple as once thought, due to the possibility of glitches
99 * from the order that the CON and DAT registers are set in.
100 *
101 * The three states the pin can be are {IN,OUT,SFN} which gives us 9
102 * combinations of changes to check. Three of these, if the pin stays
103 * in the same configuration can be discounted. This leaves us with
104 * the following:
105 *
106 * { IN => OUT }  Change DAT first
107 * { IN => SFN }  Change CON first
108 * { OUT => SFN } Change CON first, so new data will not glitch
109 * { OUT => IN }  Change CON first, so new data will not glitch
110 * { SFN => IN }  Change CON first
111 * { SFN => OUT } Change DAT first, so new data will not glitch [1]
112 *
113 * We do not currently deal with the UP registers as these control
114 * weak resistors, so a small delay in change should not need to bring
115 * these into the calculations.
116 *
117 * [1] this assumes that writing to a pin DAT whilst in SFN will set the
118 *     state for when it is next output.
119 */
120static void samsung_gpio_pm_2bit_resume(struct samsung_gpio_chip *chip)
121{
122	void __iomem *base = chip->base;
123	u32 old_gpcon = __raw_readl(base + OFFS_CON);
124	u32 old_gpdat = __raw_readl(base + OFFS_DAT);
125	u32 gps_gpcon = chip->pm_save[0];
126	u32 gps_gpdat = chip->pm_save[1];
127	u32 gpcon, old, new, mask;
128	u32 change_mask = 0x0;
129	int nr;
130
131	/* restore GPIO pull-up settings */
132	__raw_writel(chip->pm_save[2], base + OFFS_UP);
133
134	/* Create a change_mask of all the items that need to have
135	 * their CON value changed before their DAT value, so that
136	 * we minimise the work between the two settings.
137	 */
138
139	for (nr = 0, mask = 0x03; nr < 32; nr += 2, mask <<= 2) {
140		old = (old_gpcon & mask) >> nr;
141		new = (gps_gpcon & mask) >> nr;
142
143		/* If there is no change, then skip */
144
145		if (old == new)
146			continue;
147
148		/* If both are special function, then skip */
149
150		if (is_sfn(old) && is_sfn(new))
151			continue;
152
153		/* Change is IN => OUT, do not change now */
154
155		if (is_in(old) && is_out(new))
156			continue;
157
158		/* Change is SFN => OUT, do not change now */
159
160		if (is_sfn(old) && is_out(new))
161			continue;
162
163		/* We should now be at the case of IN=>SFN,
164		 * OUT=>SFN, OUT=>IN, SFN=>IN. */
165
166		change_mask |= mask;
167	}
168
169
170	/* Write the new CON settings */
171
172	gpcon = old_gpcon & ~change_mask;
173	gpcon |= gps_gpcon & change_mask;
174
175	__raw_writel(gpcon, base + OFFS_CON);
176
177	/* Now change any items that require DAT,CON */
178
179	__raw_writel(gps_gpdat, base + OFFS_DAT);
180	__raw_writel(gps_gpcon, base + OFFS_CON);
181
182	S3C_PMDBG("%s: CON %08x => %08x, DAT %08x => %08x\n",
183		  chip->chip.label, old_gpcon, gps_gpcon, old_gpdat, gps_gpdat);
184}
185
186struct samsung_gpio_pm samsung_gpio_pm_2bit = {
187	.save	= samsung_gpio_pm_2bit_save,
188	.resume = samsung_gpio_pm_2bit_resume,
189};
190
191#if defined(CONFIG_ARCH_S3C64XX)
192static void samsung_gpio_pm_4bit_save(struct samsung_gpio_chip *chip)
193{
194	chip->pm_save[1] = __raw_readl(chip->base + OFFS_CON);
195	chip->pm_save[2] = __raw_readl(chip->base + OFFS_DAT);
196	chip->pm_save[3] = __raw_readl(chip->base + OFFS_UP);
197
198	if (chip->chip.ngpio > 8)
199		chip->pm_save[0] = __raw_readl(chip->base - 4);
200}
201
202static u32 samsung_gpio_pm_4bit_mask(u32 old_gpcon, u32 gps_gpcon)
203{
204	u32 old, new, mask;
205	u32 change_mask = 0x0;
206	int nr;
207
208	for (nr = 0, mask = 0x0f; nr < 16; nr += 4, mask <<= 4) {
209		old = (old_gpcon & mask) >> nr;
210		new = (gps_gpcon & mask) >> nr;
211
212		/* If there is no change, then skip */
213
214		if (old == new)
215			continue;
216
217		/* If both are special function, then skip */
218
219		if (is_sfn(old) && is_sfn(new))
220			continue;
221
222		/* Change is IN => OUT, do not change now */
223
224		if (is_in(old) && is_out(new))
225			continue;
226
227		/* Change is SFN => OUT, do not change now */
228
229		if (is_sfn(old) && is_out(new))
230			continue;
231
232		/* We should now be at the case of IN=>SFN,
233		 * OUT=>SFN, OUT=>IN, SFN=>IN. */
234
235		change_mask |= mask;
236	}
237
238	return change_mask;
239}
240
241static void samsung_gpio_pm_4bit_con(struct samsung_gpio_chip *chip, int index)
242{
243	void __iomem *con = chip->base + (index * 4);
244	u32 old_gpcon = __raw_readl(con);
245	u32 gps_gpcon = chip->pm_save[index + 1];
246	u32 gpcon, mask;
247
248	mask = samsung_gpio_pm_4bit_mask(old_gpcon, gps_gpcon);
249
250	gpcon = old_gpcon & ~mask;
251	gpcon |= gps_gpcon & mask;
252
253	__raw_writel(gpcon, con);
254}
255
256static void samsung_gpio_pm_4bit_resume(struct samsung_gpio_chip *chip)
257{
258	void __iomem *base = chip->base;
259	u32 old_gpcon[2];
260	u32 old_gpdat = __raw_readl(base + OFFS_DAT);
261	u32 gps_gpdat = chip->pm_save[2];
262
263	/* First, modify the CON settings */
264
265	old_gpcon[0] = 0;
266	old_gpcon[1] = __raw_readl(base + OFFS_CON);
267
268	samsung_gpio_pm_4bit_con(chip, 0);
269	if (chip->chip.ngpio > 8) {
270		old_gpcon[0] = __raw_readl(base - 4);
271		samsung_gpio_pm_4bit_con(chip, -1);
272	}
273
274	/* Now change the configurations that require DAT,CON */
275
276	__raw_writel(chip->pm_save[2], base + OFFS_DAT);
277	__raw_writel(chip->pm_save[1], base + OFFS_CON);
278	if (chip->chip.ngpio > 8)
279		__raw_writel(chip->pm_save[0], base - 4);
280
281	__raw_writel(chip->pm_save[2], base + OFFS_DAT);
282	__raw_writel(chip->pm_save[3], base + OFFS_UP);
283
284	if (chip->chip.ngpio > 8) {
285		S3C_PMDBG("%s: CON4 %08x,%08x => %08x,%08x, DAT %08x => %08x\n",
286			  chip->chip.label, old_gpcon[0], old_gpcon[1],
287			  __raw_readl(base - 4),
288			  __raw_readl(base + OFFS_CON),
289			  old_gpdat, gps_gpdat);
290	} else
291		S3C_PMDBG("%s: CON4 %08x => %08x, DAT %08x => %08x\n",
292			  chip->chip.label, old_gpcon[1],
293			  __raw_readl(base + OFFS_CON),
294			  old_gpdat, gps_gpdat);
295}
296
297struct samsung_gpio_pm samsung_gpio_pm_4bit = {
298	.save	= samsung_gpio_pm_4bit_save,
299	.resume = samsung_gpio_pm_4bit_resume,
300};
301#endif /* CONFIG_ARCH_S3C64XX */
302
303/**
304 * samsung_pm_save_gpio() - save gpio chip data for suspend
305 * @ourchip: The chip for suspend.
306 */
307static void samsung_pm_save_gpio(struct samsung_gpio_chip *ourchip)
308{
309	struct samsung_gpio_pm *pm = ourchip->pm;
310
311	if (pm == NULL || pm->save == NULL)
312		S3C_PMDBG("%s: no pm for %s\n", __func__, ourchip->chip.label);
313	else
314		pm->save(ourchip);
315}
316
317/**
318 * samsung_pm_save_gpios() - Save the state of the GPIO banks.
319 *
320 * For all the GPIO banks, save the state of each one ready for going
321 * into a suspend mode.
322 */
323void samsung_pm_save_gpios(void)
324{
325	struct samsung_gpio_chip *ourchip;
326	unsigned int gpio_nr;
327
328	for (gpio_nr = 0; gpio_nr < S3C_GPIO_END;) {
329		ourchip = samsung_gpiolib_getchip(gpio_nr);
330		if (!ourchip) {
331			gpio_nr++;
332			continue;
333		}
334
335		samsung_pm_save_gpio(ourchip);
336
337		S3C_PMDBG("%s: save %08x,%08x,%08x,%08x\n",
338			  ourchip->chip.label,
339			  ourchip->pm_save[0],
340			  ourchip->pm_save[1],
341			  ourchip->pm_save[2],
342			  ourchip->pm_save[3]);
343
344		gpio_nr += ourchip->chip.ngpio;
345		gpio_nr += CONFIG_S3C_GPIO_SPACE;
346	}
347}
348
349/**
350 * samsung_pm_resume_gpio() - restore gpio chip data after suspend
351 * @ourchip: The suspended chip.
352 */
353static void samsung_pm_resume_gpio(struct samsung_gpio_chip *ourchip)
354{
355	struct samsung_gpio_pm *pm = ourchip->pm;
356
357	if (pm == NULL || pm->resume == NULL)
358		S3C_PMDBG("%s: no pm for %s\n", __func__, ourchip->chip.label);
359	else
360		pm->resume(ourchip);
361}
362
363void samsung_pm_restore_gpios(void)
364{
365	struct samsung_gpio_chip *ourchip;
366	unsigned int gpio_nr;
367
368	for (gpio_nr = 0; gpio_nr < S3C_GPIO_END;) {
369		ourchip = samsung_gpiolib_getchip(gpio_nr);
370		if (!ourchip) {
371			gpio_nr++;
372			continue;
373		}
374
375		samsung_pm_resume_gpio(ourchip);
376
377		gpio_nr += ourchip->chip.ngpio;
378		gpio_nr += CONFIG_S3C_GPIO_SPACE;
379	}
380}
381