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v6.8
  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * AMD CS5535/CS5536 GPIO driver
  4 * Copyright (C) 2006  Advanced Micro Devices, Inc.
  5 * Copyright (C) 2007-2009  Andres Salomon <dilinger@collabora.co.uk>
 
 
 
 
  6 */
  7
  8#include <linux/kernel.h>
  9#include <linux/spinlock.h>
 10#include <linux/module.h>
 11#include <linux/platform_device.h>
 12#include <linux/gpio/driver.h>
 13#include <linux/io.h>
 14#include <linux/cs5535.h>
 15#include <asm/msr.h>
 16
 17#define DRV_NAME "cs5535-gpio"
 18
 19/*
 20 * Some GPIO pins
 21 *  31-29,23 : reserved (always mask out)
 22 *  28       : Power Button
 23 *  26       : PME#
 24 *  22-16    : LPC
 25 *  14,15    : SMBus
 26 *  9,8      : UART1
 27 *  7        : PCI INTB
 28 *  3,4      : UART2/DDC
 29 *  2        : IDE_IRQ0
 30 *  1        : AC_BEEP
 31 *  0        : PCI INTA
 32 *
 33 * If a mask was not specified, allow all except
 34 * reserved and Power Button
 35 */
 36#define GPIO_DEFAULT_MASK 0x0F7FFFFF
 37
 38static ulong mask = GPIO_DEFAULT_MASK;
 39module_param_named(mask, mask, ulong, 0444);
 40MODULE_PARM_DESC(mask, "GPIO channel mask.");
 41
 42/*
 43 * FIXME: convert this singleton driver to use the state container
 44 * design pattern, see Documentation/driver-api/driver-model/design-patterns.rst
 45 */
 46static struct cs5535_gpio_chip {
 47	struct gpio_chip chip;
 48	resource_size_t base;
 49
 50	struct platform_device *pdev;
 51	spinlock_t lock;
 52} cs5535_gpio_chip;
 53
 54/*
 55 * The CS5535/CS5536 GPIOs support a number of extra features not defined
 56 * by the gpio_chip API, so these are exported.  For a full list of the
 57 * registers, see include/linux/cs5535.h.
 58 */
 59
 60static void errata_outl(struct cs5535_gpio_chip *chip, u32 val,
 61		unsigned int reg)
 62{
 63	unsigned long addr = chip->base + 0x80 + reg;
 64
 65	/*
 66	 * According to the CS5536 errata (#36), after suspend
 67	 * a write to the high bank GPIO register will clear all
 68	 * non-selected bits; the recommended workaround is a
 69	 * read-modify-write operation.
 70	 *
 71	 * Don't apply this errata to the edge status GPIOs, as writing
 72	 * to their lower bits will clear them.
 73	 */
 74	if (reg != GPIO_POSITIVE_EDGE_STS && reg != GPIO_NEGATIVE_EDGE_STS) {
 75		if (val & 0xffff)
 76			val |= (inl(addr) & 0xffff); /* ignore the high bits */
 77		else
 78			val |= (inl(addr) ^ (val >> 16));
 79	}
 80	outl(val, addr);
 81}
 82
 83static void __cs5535_gpio_set(struct cs5535_gpio_chip *chip, unsigned offset,
 84		unsigned int reg)
 85{
 86	if (offset < 16)
 87		/* low bank register */
 88		outl(1 << offset, chip->base + reg);
 89	else
 90		/* high bank register */
 91		errata_outl(chip, 1 << (offset - 16), reg);
 92}
 93
 94void cs5535_gpio_set(unsigned offset, unsigned int reg)
 95{
 96	struct cs5535_gpio_chip *chip = &cs5535_gpio_chip;
 97	unsigned long flags;
 98
 99	spin_lock_irqsave(&chip->lock, flags);
100	__cs5535_gpio_set(chip, offset, reg);
101	spin_unlock_irqrestore(&chip->lock, flags);
102}
103EXPORT_SYMBOL_GPL(cs5535_gpio_set);
104
105static void __cs5535_gpio_clear(struct cs5535_gpio_chip *chip, unsigned offset,
106		unsigned int reg)
107{
108	if (offset < 16)
109		/* low bank register */
110		outl(1 << (offset + 16), chip->base + reg);
111	else
112		/* high bank register */
113		errata_outl(chip, 1 << offset, reg);
114}
115
116void cs5535_gpio_clear(unsigned offset, unsigned int reg)
117{
118	struct cs5535_gpio_chip *chip = &cs5535_gpio_chip;
119	unsigned long flags;
120
121	spin_lock_irqsave(&chip->lock, flags);
122	__cs5535_gpio_clear(chip, offset, reg);
123	spin_unlock_irqrestore(&chip->lock, flags);
124}
125EXPORT_SYMBOL_GPL(cs5535_gpio_clear);
126
127int cs5535_gpio_isset(unsigned offset, unsigned int reg)
128{
129	struct cs5535_gpio_chip *chip = &cs5535_gpio_chip;
130	unsigned long flags;
131	long val;
132
133	spin_lock_irqsave(&chip->lock, flags);
134	if (offset < 16)
135		/* low bank register */
136		val = inl(chip->base + reg);
137	else {
138		/* high bank register */
139		val = inl(chip->base + 0x80 + reg);
140		offset -= 16;
141	}
142	spin_unlock_irqrestore(&chip->lock, flags);
143
144	return (val & (1 << offset)) ? 1 : 0;
145}
146EXPORT_SYMBOL_GPL(cs5535_gpio_isset);
147
148int cs5535_gpio_set_irq(unsigned group, unsigned irq)
149{
150	uint32_t lo, hi;
151
152	if (group > 7 || irq > 15)
153		return -EINVAL;
154
155	rdmsr(MSR_PIC_ZSEL_HIGH, lo, hi);
156
157	lo &= ~(0xF << (group * 4));
158	lo |= (irq & 0xF) << (group * 4);
159
160	wrmsr(MSR_PIC_ZSEL_HIGH, lo, hi);
161	return 0;
162}
163EXPORT_SYMBOL_GPL(cs5535_gpio_set_irq);
164
165void cs5535_gpio_setup_event(unsigned offset, int pair, int pme)
166{
167	struct cs5535_gpio_chip *chip = &cs5535_gpio_chip;
168	uint32_t shift = (offset % 8) * 4;
169	unsigned long flags;
170	uint32_t val;
171
172	if (offset >= 24)
173		offset = GPIO_MAP_W;
174	else if (offset >= 16)
175		offset = GPIO_MAP_Z;
176	else if (offset >= 8)
177		offset = GPIO_MAP_Y;
178	else
179		offset = GPIO_MAP_X;
180
181	spin_lock_irqsave(&chip->lock, flags);
182	val = inl(chip->base + offset);
183
184	/* Clear whatever was there before */
185	val &= ~(0xF << shift);
186
187	/* Set the new value */
188	val |= ((pair & 7) << shift);
189
190	/* Set the PME bit if this is a PME event */
191	if (pme)
192		val |= (1 << (shift + 3));
193
194	outl(val, chip->base + offset);
195	spin_unlock_irqrestore(&chip->lock, flags);
196}
197EXPORT_SYMBOL_GPL(cs5535_gpio_setup_event);
198
199/*
200 * Generic gpio_chip API support.
201 */
202
203static int chip_gpio_request(struct gpio_chip *c, unsigned offset)
204{
205	struct cs5535_gpio_chip *chip = gpiochip_get_data(c);
206	unsigned long flags;
207
208	spin_lock_irqsave(&chip->lock, flags);
209
210	/* check if this pin is available */
211	if ((mask & (1 << offset)) == 0) {
212		dev_info(&chip->pdev->dev,
213			"pin %u is not available (check mask)\n", offset);
214		spin_unlock_irqrestore(&chip->lock, flags);
215		return -EINVAL;
216	}
217
218	/* disable output aux 1 & 2 on this pin */
219	__cs5535_gpio_clear(chip, offset, GPIO_OUTPUT_AUX1);
220	__cs5535_gpio_clear(chip, offset, GPIO_OUTPUT_AUX2);
221
222	/* disable input aux 1 on this pin */
223	__cs5535_gpio_clear(chip, offset, GPIO_INPUT_AUX1);
224
225	spin_unlock_irqrestore(&chip->lock, flags);
226
227	return 0;
228}
229
230static int chip_gpio_get(struct gpio_chip *chip, unsigned offset)
231{
232	return cs5535_gpio_isset(offset, GPIO_READ_BACK);
233}
234
235static void chip_gpio_set(struct gpio_chip *chip, unsigned offset, int val)
236{
237	if (val)
238		cs5535_gpio_set(offset, GPIO_OUTPUT_VAL);
239	else
240		cs5535_gpio_clear(offset, GPIO_OUTPUT_VAL);
241}
242
243static int chip_direction_input(struct gpio_chip *c, unsigned offset)
244{
245	struct cs5535_gpio_chip *chip = gpiochip_get_data(c);
246	unsigned long flags;
247
248	spin_lock_irqsave(&chip->lock, flags);
249	__cs5535_gpio_set(chip, offset, GPIO_INPUT_ENABLE);
250	__cs5535_gpio_clear(chip, offset, GPIO_OUTPUT_ENABLE);
251	spin_unlock_irqrestore(&chip->lock, flags);
252
253	return 0;
254}
255
256static int chip_direction_output(struct gpio_chip *c, unsigned offset, int val)
257{
258	struct cs5535_gpio_chip *chip = gpiochip_get_data(c);
259	unsigned long flags;
260
261	spin_lock_irqsave(&chip->lock, flags);
262
263	__cs5535_gpio_set(chip, offset, GPIO_INPUT_ENABLE);
264	__cs5535_gpio_set(chip, offset, GPIO_OUTPUT_ENABLE);
265	if (val)
266		__cs5535_gpio_set(chip, offset, GPIO_OUTPUT_VAL);
267	else
268		__cs5535_gpio_clear(chip, offset, GPIO_OUTPUT_VAL);
269
270	spin_unlock_irqrestore(&chip->lock, flags);
271
272	return 0;
273}
274
275static const char * const cs5535_gpio_names[] = {
276	"GPIO0", "GPIO1", "GPIO2", "GPIO3",
277	"GPIO4", "GPIO5", "GPIO6", "GPIO7",
278	"GPIO8", "GPIO9", "GPIO10", "GPIO11",
279	"GPIO12", "GPIO13", "GPIO14", "GPIO15",
280	"GPIO16", "GPIO17", "GPIO18", "GPIO19",
281	"GPIO20", "GPIO21", "GPIO22", NULL,
282	"GPIO24", "GPIO25", "GPIO26", "GPIO27",
283	"GPIO28", NULL, NULL, NULL,
284};
285
286static struct cs5535_gpio_chip cs5535_gpio_chip = {
287	.chip = {
288		.owner = THIS_MODULE,
289		.label = DRV_NAME,
290
291		.base = 0,
292		.ngpio = 32,
293		.names = cs5535_gpio_names,
294		.request = chip_gpio_request,
295
296		.get = chip_gpio_get,
297		.set = chip_gpio_set,
298
299		.direction_input = chip_direction_input,
300		.direction_output = chip_direction_output,
301	},
302};
303
304static int cs5535_gpio_probe(struct platform_device *pdev)
305{
306	struct resource *res;
307	int err = -EIO;
308	ulong mask_orig = mask;
309
310	/* There are two ways to get the GPIO base address; one is by
311	 * fetching it from MSR_LBAR_GPIO, the other is by reading the
312	 * PCI BAR info.  The latter method is easier (especially across
313	 * different architectures), so we'll stick with that for now.  If
314	 * it turns out to be unreliable in the face of crappy BIOSes, we
315	 * can always go back to using MSRs.. */
316
317	res = platform_get_resource(pdev, IORESOURCE_IO, 0);
318	if (!res) {
319		dev_err(&pdev->dev, "can't fetch device resource info\n");
320		return err;
321	}
322
323	if (!devm_request_region(&pdev->dev, res->start, resource_size(res),
324				 pdev->name)) {
325		dev_err(&pdev->dev, "can't request region\n");
326		return err;
327	}
328
329	/* set up the driver-specific struct */
330	cs5535_gpio_chip.base = res->start;
331	cs5535_gpio_chip.pdev = pdev;
332	spin_lock_init(&cs5535_gpio_chip.lock);
333
334	dev_info(&pdev->dev, "reserved resource region %pR\n", res);
335
336	/* mask out reserved pins */
337	mask &= 0x1F7FFFFF;
338
339	/* do not allow pin 28, Power Button, as there's special handling
340	 * in the PMC needed. (note 12, p. 48) */
341	mask &= ~(1 << 28);
342
343	if (mask_orig != mask)
344		dev_info(&pdev->dev, "mask changed from 0x%08lX to 0x%08lX\n",
345				mask_orig, mask);
346
347	/* finally, register with the generic GPIO API */
348	return devm_gpiochip_add_data(&pdev->dev, &cs5535_gpio_chip.chip,
349				      &cs5535_gpio_chip);
 
 
 
 
350}
351
352static struct platform_driver cs5535_gpio_driver = {
353	.driver = {
354		.name = DRV_NAME,
355	},
356	.probe = cs5535_gpio_probe,
357};
358
359module_platform_driver(cs5535_gpio_driver);
360
361MODULE_AUTHOR("Andres Salomon <dilinger@queued.net>");
362MODULE_DESCRIPTION("AMD CS5535/CS5536 GPIO driver");
363MODULE_LICENSE("GPL");
364MODULE_ALIAS("platform:" DRV_NAME);
v4.6
 
  1/*
  2 * AMD CS5535/CS5536 GPIO driver
  3 * Copyright (C) 2006  Advanced Micro Devices, Inc.
  4 * Copyright (C) 2007-2009  Andres Salomon <dilinger@collabora.co.uk>
  5 *
  6 * This program is free software; you can redistribute it and/or
  7 * modify it under the terms of version 2 of the GNU General Public License
  8 * as published by the Free Software Foundation.
  9 */
 10
 11#include <linux/kernel.h>
 12#include <linux/spinlock.h>
 13#include <linux/module.h>
 14#include <linux/platform_device.h>
 15#include <linux/gpio.h>
 16#include <linux/io.h>
 17#include <linux/cs5535.h>
 18#include <asm/msr.h>
 19
 20#define DRV_NAME "cs5535-gpio"
 21
 22/*
 23 * Some GPIO pins
 24 *  31-29,23 : reserved (always mask out)
 25 *  28       : Power Button
 26 *  26       : PME#
 27 *  22-16    : LPC
 28 *  14,15    : SMBus
 29 *  9,8      : UART1
 30 *  7        : PCI INTB
 31 *  3,4      : UART2/DDC
 32 *  2        : IDE_IRQ0
 33 *  1        : AC_BEEP
 34 *  0        : PCI INTA
 35 *
 36 * If a mask was not specified, allow all except
 37 * reserved and Power Button
 38 */
 39#define GPIO_DEFAULT_MASK 0x0F7FFFFF
 40
 41static ulong mask = GPIO_DEFAULT_MASK;
 42module_param_named(mask, mask, ulong, 0444);
 43MODULE_PARM_DESC(mask, "GPIO channel mask.");
 44
 45/*
 46 * FIXME: convert this singleton driver to use the state container
 47 * design pattern, see Documentation/driver-model/design-patterns.txt
 48 */
 49static struct cs5535_gpio_chip {
 50	struct gpio_chip chip;
 51	resource_size_t base;
 52
 53	struct platform_device *pdev;
 54	spinlock_t lock;
 55} cs5535_gpio_chip;
 56
 57/*
 58 * The CS5535/CS5536 GPIOs support a number of extra features not defined
 59 * by the gpio_chip API, so these are exported.  For a full list of the
 60 * registers, see include/linux/cs5535.h.
 61 */
 62
 63static void errata_outl(struct cs5535_gpio_chip *chip, u32 val,
 64		unsigned int reg)
 65{
 66	unsigned long addr = chip->base + 0x80 + reg;
 67
 68	/*
 69	 * According to the CS5536 errata (#36), after suspend
 70	 * a write to the high bank GPIO register will clear all
 71	 * non-selected bits; the recommended workaround is a
 72	 * read-modify-write operation.
 73	 *
 74	 * Don't apply this errata to the edge status GPIOs, as writing
 75	 * to their lower bits will clear them.
 76	 */
 77	if (reg != GPIO_POSITIVE_EDGE_STS && reg != GPIO_NEGATIVE_EDGE_STS) {
 78		if (val & 0xffff)
 79			val |= (inl(addr) & 0xffff); /* ignore the high bits */
 80		else
 81			val |= (inl(addr) ^ (val >> 16));
 82	}
 83	outl(val, addr);
 84}
 85
 86static void __cs5535_gpio_set(struct cs5535_gpio_chip *chip, unsigned offset,
 87		unsigned int reg)
 88{
 89	if (offset < 16)
 90		/* low bank register */
 91		outl(1 << offset, chip->base + reg);
 92	else
 93		/* high bank register */
 94		errata_outl(chip, 1 << (offset - 16), reg);
 95}
 96
 97void cs5535_gpio_set(unsigned offset, unsigned int reg)
 98{
 99	struct cs5535_gpio_chip *chip = &cs5535_gpio_chip;
100	unsigned long flags;
101
102	spin_lock_irqsave(&chip->lock, flags);
103	__cs5535_gpio_set(chip, offset, reg);
104	spin_unlock_irqrestore(&chip->lock, flags);
105}
106EXPORT_SYMBOL_GPL(cs5535_gpio_set);
107
108static void __cs5535_gpio_clear(struct cs5535_gpio_chip *chip, unsigned offset,
109		unsigned int reg)
110{
111	if (offset < 16)
112		/* low bank register */
113		outl(1 << (offset + 16), chip->base + reg);
114	else
115		/* high bank register */
116		errata_outl(chip, 1 << offset, reg);
117}
118
119void cs5535_gpio_clear(unsigned offset, unsigned int reg)
120{
121	struct cs5535_gpio_chip *chip = &cs5535_gpio_chip;
122	unsigned long flags;
123
124	spin_lock_irqsave(&chip->lock, flags);
125	__cs5535_gpio_clear(chip, offset, reg);
126	spin_unlock_irqrestore(&chip->lock, flags);
127}
128EXPORT_SYMBOL_GPL(cs5535_gpio_clear);
129
130int cs5535_gpio_isset(unsigned offset, unsigned int reg)
131{
132	struct cs5535_gpio_chip *chip = &cs5535_gpio_chip;
133	unsigned long flags;
134	long val;
135
136	spin_lock_irqsave(&chip->lock, flags);
137	if (offset < 16)
138		/* low bank register */
139		val = inl(chip->base + reg);
140	else {
141		/* high bank register */
142		val = inl(chip->base + 0x80 + reg);
143		offset -= 16;
144	}
145	spin_unlock_irqrestore(&chip->lock, flags);
146
147	return (val & (1 << offset)) ? 1 : 0;
148}
149EXPORT_SYMBOL_GPL(cs5535_gpio_isset);
150
151int cs5535_gpio_set_irq(unsigned group, unsigned irq)
152{
153	uint32_t lo, hi;
154
155	if (group > 7 || irq > 15)
156		return -EINVAL;
157
158	rdmsr(MSR_PIC_ZSEL_HIGH, lo, hi);
159
160	lo &= ~(0xF << (group * 4));
161	lo |= (irq & 0xF) << (group * 4);
162
163	wrmsr(MSR_PIC_ZSEL_HIGH, lo, hi);
164	return 0;
165}
166EXPORT_SYMBOL_GPL(cs5535_gpio_set_irq);
167
168void cs5535_gpio_setup_event(unsigned offset, int pair, int pme)
169{
170	struct cs5535_gpio_chip *chip = &cs5535_gpio_chip;
171	uint32_t shift = (offset % 8) * 4;
172	unsigned long flags;
173	uint32_t val;
174
175	if (offset >= 24)
176		offset = GPIO_MAP_W;
177	else if (offset >= 16)
178		offset = GPIO_MAP_Z;
179	else if (offset >= 8)
180		offset = GPIO_MAP_Y;
181	else
182		offset = GPIO_MAP_X;
183
184	spin_lock_irqsave(&chip->lock, flags);
185	val = inl(chip->base + offset);
186
187	/* Clear whatever was there before */
188	val &= ~(0xF << shift);
189
190	/* Set the new value */
191	val |= ((pair & 7) << shift);
192
193	/* Set the PME bit if this is a PME event */
194	if (pme)
195		val |= (1 << (shift + 3));
196
197	outl(val, chip->base + offset);
198	spin_unlock_irqrestore(&chip->lock, flags);
199}
200EXPORT_SYMBOL_GPL(cs5535_gpio_setup_event);
201
202/*
203 * Generic gpio_chip API support.
204 */
205
206static int chip_gpio_request(struct gpio_chip *c, unsigned offset)
207{
208	struct cs5535_gpio_chip *chip = gpiochip_get_data(c);
209	unsigned long flags;
210
211	spin_lock_irqsave(&chip->lock, flags);
212
213	/* check if this pin is available */
214	if ((mask & (1 << offset)) == 0) {
215		dev_info(&chip->pdev->dev,
216			"pin %u is not available (check mask)\n", offset);
217		spin_unlock_irqrestore(&chip->lock, flags);
218		return -EINVAL;
219	}
220
221	/* disable output aux 1 & 2 on this pin */
222	__cs5535_gpio_clear(chip, offset, GPIO_OUTPUT_AUX1);
223	__cs5535_gpio_clear(chip, offset, GPIO_OUTPUT_AUX2);
224
225	/* disable input aux 1 on this pin */
226	__cs5535_gpio_clear(chip, offset, GPIO_INPUT_AUX1);
227
228	spin_unlock_irqrestore(&chip->lock, flags);
229
230	return 0;
231}
232
233static int chip_gpio_get(struct gpio_chip *chip, unsigned offset)
234{
235	return cs5535_gpio_isset(offset, GPIO_READ_BACK);
236}
237
238static void chip_gpio_set(struct gpio_chip *chip, unsigned offset, int val)
239{
240	if (val)
241		cs5535_gpio_set(offset, GPIO_OUTPUT_VAL);
242	else
243		cs5535_gpio_clear(offset, GPIO_OUTPUT_VAL);
244}
245
246static int chip_direction_input(struct gpio_chip *c, unsigned offset)
247{
248	struct cs5535_gpio_chip *chip = gpiochip_get_data(c);
249	unsigned long flags;
250
251	spin_lock_irqsave(&chip->lock, flags);
252	__cs5535_gpio_set(chip, offset, GPIO_INPUT_ENABLE);
253	__cs5535_gpio_clear(chip, offset, GPIO_OUTPUT_ENABLE);
254	spin_unlock_irqrestore(&chip->lock, flags);
255
256	return 0;
257}
258
259static int chip_direction_output(struct gpio_chip *c, unsigned offset, int val)
260{
261	struct cs5535_gpio_chip *chip = gpiochip_get_data(c);
262	unsigned long flags;
263
264	spin_lock_irqsave(&chip->lock, flags);
265
266	__cs5535_gpio_set(chip, offset, GPIO_INPUT_ENABLE);
267	__cs5535_gpio_set(chip, offset, GPIO_OUTPUT_ENABLE);
268	if (val)
269		__cs5535_gpio_set(chip, offset, GPIO_OUTPUT_VAL);
270	else
271		__cs5535_gpio_clear(chip, offset, GPIO_OUTPUT_VAL);
272
273	spin_unlock_irqrestore(&chip->lock, flags);
274
275	return 0;
276}
277
278static const char * const cs5535_gpio_names[] = {
279	"GPIO0", "GPIO1", "GPIO2", "GPIO3",
280	"GPIO4", "GPIO5", "GPIO6", "GPIO7",
281	"GPIO8", "GPIO9", "GPIO10", "GPIO11",
282	"GPIO12", "GPIO13", "GPIO14", "GPIO15",
283	"GPIO16", "GPIO17", "GPIO18", "GPIO19",
284	"GPIO20", "GPIO21", "GPIO22", NULL,
285	"GPIO24", "GPIO25", "GPIO26", "GPIO27",
286	"GPIO28", NULL, NULL, NULL,
287};
288
289static struct cs5535_gpio_chip cs5535_gpio_chip = {
290	.chip = {
291		.owner = THIS_MODULE,
292		.label = DRV_NAME,
293
294		.base = 0,
295		.ngpio = 32,
296		.names = cs5535_gpio_names,
297		.request = chip_gpio_request,
298
299		.get = chip_gpio_get,
300		.set = chip_gpio_set,
301
302		.direction_input = chip_direction_input,
303		.direction_output = chip_direction_output,
304	},
305};
306
307static int cs5535_gpio_probe(struct platform_device *pdev)
308{
309	struct resource *res;
310	int err = -EIO;
311	ulong mask_orig = mask;
312
313	/* There are two ways to get the GPIO base address; one is by
314	 * fetching it from MSR_LBAR_GPIO, the other is by reading the
315	 * PCI BAR info.  The latter method is easier (especially across
316	 * different architectures), so we'll stick with that for now.  If
317	 * it turns out to be unreliable in the face of crappy BIOSes, we
318	 * can always go back to using MSRs.. */
319
320	res = platform_get_resource(pdev, IORESOURCE_IO, 0);
321	if (!res) {
322		dev_err(&pdev->dev, "can't fetch device resource info\n");
323		return err;
324	}
325
326	if (!devm_request_region(&pdev->dev, res->start, resource_size(res),
327				 pdev->name)) {
328		dev_err(&pdev->dev, "can't request region\n");
329		return err;
330	}
331
332	/* set up the driver-specific struct */
333	cs5535_gpio_chip.base = res->start;
334	cs5535_gpio_chip.pdev = pdev;
335	spin_lock_init(&cs5535_gpio_chip.lock);
336
337	dev_info(&pdev->dev, "reserved resource region %pR\n", res);
338
339	/* mask out reserved pins */
340	mask &= 0x1F7FFFFF;
341
342	/* do not allow pin 28, Power Button, as there's special handling
343	 * in the PMC needed. (note 12, p. 48) */
344	mask &= ~(1 << 28);
345
346	if (mask_orig != mask)
347		dev_info(&pdev->dev, "mask changed from 0x%08lX to 0x%08lX\n",
348				mask_orig, mask);
349
350	/* finally, register with the generic GPIO API */
351	err = devm_gpiochip_add_data(&pdev->dev, &cs5535_gpio_chip.chip,
352				     &cs5535_gpio_chip);
353	if (err)
354		return err;
355
356	return 0;
357}
358
359static struct platform_driver cs5535_gpio_driver = {
360	.driver = {
361		.name = DRV_NAME,
362	},
363	.probe = cs5535_gpio_probe,
364};
365
366module_platform_driver(cs5535_gpio_driver);
367
368MODULE_AUTHOR("Andres Salomon <dilinger@queued.net>");
369MODULE_DESCRIPTION("AMD CS5535/CS5536 GPIO driver");
370MODULE_LICENSE("GPL");
371MODULE_ALIAS("platform:" DRV_NAME);