summaryrefslogtreecommitdiff
path: root/drivers/mmc/core/slot-gpio.c
blob: 69bbf2adb329db5570b0c0b698152110fb2ccee4 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
/*
 * Generic GPIO card-detect helper
 *
 * Copyright (C) 2011, Guennadi Liakhovetski <g.liakhovetski@gmx.de>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/err.h>
#include <linux/gpio.h>
#include <linux/gpio/consumer.h>
#include <linux/interrupt.h>
#include <linux/jiffies.h>
#include <linux/mmc/host.h>
#include <linux/mmc/slot-gpio.h>
#include <linux/module.h>
#include <linux/slab.h>

struct mmc_gpio {
	struct gpio_desc *ro_gpio;
	struct gpio_desc *cd_gpio;
	bool override_ro_active_level;
	bool override_cd_active_level;
	char *ro_label;
	char cd_label[0];
};

static irqreturn_t mmc_gpio_cd_irqt(int irq, void *dev_id)
{
	/* Schedule a card detection after a debounce timeout */
	struct mmc_host *host = dev_id;

	host->trigger_card_event = true;
	mmc_detect_change(host, msecs_to_jiffies(200));

	return IRQ_HANDLED;
}

static int mmc_gpio_alloc(struct mmc_host *host)
{
	size_t len = strlen(dev_name(host->parent)) + 4;
	struct mmc_gpio *ctx;

	mutex_lock(&host->slot.lock);

	ctx = host->slot.handler_priv;
	if (!ctx) {
		/*
		 * devm_kzalloc() can be called after device_initialize(), even
		 * before device_add(), i.e., between mmc_alloc_host() and
		 * mmc_add_host()
		 */
		ctx = devm_kzalloc(&host->class_dev, sizeof(*ctx) + 2 * len,
				   GFP_KERNEL);
		if (ctx) {
			ctx->ro_label = ctx->cd_label + len;
			snprintf(ctx->cd_label, len, "%s cd", dev_name(host->parent));
			snprintf(ctx->ro_label, len, "%s ro", dev_name(host->parent));
			host->slot.handler_priv = ctx;
		}
	}

	mutex_unlock(&host->slot.lock);

	return ctx ? 0 : -ENOMEM;
}

int mmc_gpio_get_ro(struct mmc_host *host)
{
	struct mmc_gpio *ctx = host->slot.handler_priv;

	if (!ctx || !ctx->ro_gpio)
		return -ENOSYS;

	if (ctx->override_ro_active_level)
		return !gpiod_get_raw_value_cansleep(ctx->ro_gpio) ^
			!!(host->caps2 & MMC_CAP2_RO_ACTIVE_HIGH);

	return gpiod_get_value_cansleep(ctx->ro_gpio);
}
EXPORT_SYMBOL(mmc_gpio_get_ro);

int mmc_gpio_get_cd(struct mmc_host *host)
{
	struct mmc_gpio *ctx = host->slot.handler_priv;

	if (!ctx || !ctx->cd_gpio)
		return -ENOSYS;

	if (ctx->override_cd_active_level)
		return !gpiod_get_raw_value_cansleep(ctx->cd_gpio) ^
			!!(host->caps2 & MMC_CAP2_CD_ACTIVE_HIGH);

	return gpiod_get_value_cansleep(ctx->cd_gpio);
}
EXPORT_SYMBOL(mmc_gpio_get_cd);

/**
 * mmc_gpio_request_ro - request a gpio for write-protection
 * @host: mmc host
 * @gpio: gpio number requested
 *
 * As devm_* managed functions are used in mmc_gpio_request_ro(), client
 * drivers do not need to explicitly call mmc_gpio_free_ro() for freeing up,
 * if the requesting and freeing are only needed at probing and unbinding time
 * for once.  However, if client drivers do something special like runtime
 * switching for write-protection, they are responsible for calling
 * mmc_gpio_request_ro() and mmc_gpio_free_ro() as a pair on their own.
 *
 * Returns zero on success, else an error.
 */
int mmc_gpio_request_ro(struct mmc_host *host, unsigned int gpio)
{
	struct mmc_gpio *ctx;
	int ret;

	if (!gpio_is_valid(gpio))
		return -EINVAL;

	ret = mmc_gpio_alloc(host);
	if (ret < 0)
		return ret;

	ctx = host->slot.handler_priv;

	ret = devm_gpio_request_one(&host->class_dev, gpio, GPIOF_DIR_IN,
				    ctx->ro_label);
	if (ret < 0)
		return ret;

	ctx->override_ro_active_level = true;
	ctx->ro_gpio = gpio_to_desc(gpio);

	return 0;
}
EXPORT_SYMBOL(mmc_gpio_request_ro);

void mmc_gpiod_request_cd_irq(struct mmc_host *host)
{
	struct mmc_gpio *ctx = host->slot.handler_priv;
	int ret, irq;

	if (host->slot.cd_irq >= 0 || !ctx || !ctx->cd_gpio)
		return;

	irq = gpiod_to_irq(ctx->cd_gpio);

	/*
	 * Even if gpiod_to_irq() returns a valid IRQ number, the platform might
	 * still prefer to poll, e.g., because that IRQ number is already used
	 * by another unit and cannot be shared.
	 */
	if (irq >= 0 && host->caps & MMC_CAP_NEEDS_POLL)
		irq = -EINVAL;

	if (irq >= 0) {
		ret = devm_request_threaded_irq(&host->class_dev, irq,
			NULL, mmc_gpio_cd_irqt,
			IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
			ctx->cd_label, host);
		if (ret < 0)
			irq = ret;
	}

	host->slot.cd_irq = irq;

	if (irq < 0)
		host->caps |= MMC_CAP_NEEDS_POLL;
}
EXPORT_SYMBOL(mmc_gpiod_request_cd_irq);

/**
 * mmc_gpio_request_cd - request a gpio for card-detection
 * @host: mmc host
 * @gpio: gpio number requested
 * @debounce: debounce time in microseconds
 *
 * As devm_* managed functions are used in mmc_gpio_request_cd(), client
 * drivers do not need to explicitly call mmc_gpio_free_cd() for freeing up,
 * if the requesting and freeing are only needed at probing and unbinding time
 * for once.  However, if client drivers do something special like runtime
 * switching for card-detection, they are responsible for calling
 * mmc_gpio_request_cd() and mmc_gpio_free_cd() as a pair on their own.
 *
 * If GPIO debouncing is desired, set the debounce parameter to a non-zero
 * value. The caller is responsible for ensuring that the GPIO driver associated
 * with the GPIO supports debouncing, otherwise an error will be returned.
 *
 * Returns zero on success, else an error.
 */
int mmc_gpio_request_cd(struct mmc_host *host, unsigned int gpio,
			unsigned int debounce)
{
	struct mmc_gpio *ctx;
	int ret;

	ret = mmc_gpio_alloc(host);
	if (ret < 0)
		return ret;

	ctx = host->slot.handler_priv;

	ret = devm_gpio_request_one(&host->class_dev, gpio, GPIOF_DIR_IN,
				    ctx->cd_label);
	if (ret < 0)
		/*
		 * don't bother freeing memory. It might still get used by other
		 * slot functions, in any case it will be freed, when the device
		 * is destroyed.
		 */
		return ret;

	if (debounce) {
		ret = gpio_set_debounce(gpio, debounce);
		if (ret < 0)
			return ret;
	}

	ctx->override_cd_active_level = true;
	ctx->cd_gpio = gpio_to_desc(gpio);

	return 0;
}
EXPORT_SYMBOL(mmc_gpio_request_cd);

/**
 * mmc_gpio_free_ro - free the write-protection gpio
 * @host: mmc host
 *
 * It's provided only for cases that client drivers need to manually free
 * up the write-protection gpio requested by mmc_gpio_request_ro().
 */
void mmc_gpio_free_ro(struct mmc_host *host)
{
	struct mmc_gpio *ctx = host->slot.handler_priv;
	int gpio;

	if (!ctx || !ctx->ro_gpio)
		return;

	gpio = desc_to_gpio(ctx->ro_gpio);
	ctx->ro_gpio = NULL;

	devm_gpio_free(&host->class_dev, gpio);
}
EXPORT_SYMBOL(mmc_gpio_free_ro);

/**
 * mmc_gpio_free_cd - free the card-detection gpio
 * @host: mmc host
 *
 * It's provided only for cases that client drivers need to manually free
 * up the card-detection gpio requested by mmc_gpio_request_cd().
 */
void mmc_gpio_free_cd(struct mmc_host *host)
{
	struct mmc_gpio *ctx = host->slot.handler_priv;
	int gpio;

	if (!ctx || !ctx->cd_gpio)
		return;

	if (host->slot.cd_irq >= 0) {
		devm_free_irq(&host->class_dev, host->slot.cd_irq, host);
		host->slot.cd_irq = -EINVAL;
	}

	gpio = desc_to_gpio(ctx->cd_gpio);
	ctx->cd_gpio = NULL;

	devm_gpio_free(&host->class_dev, gpio);
}
EXPORT_SYMBOL(mmc_gpio_free_cd);

/**
 * mmc_gpiod_request_cd - request a gpio descriptor for card-detection
 * @host: mmc host
 * @con_id: function within the GPIO consumer
 * @idx: index of the GPIO to obtain in the consumer
 * @override_active_level: ignore %GPIO_ACTIVE_LOW flag
 * @debounce: debounce time in microseconds
 * @gpio_invert: will return whether the GPIO line is inverted or not, set
 * to NULL to ignore
 *
 * Use this function in place of mmc_gpio_request_cd() to use the GPIO
 * descriptor API.  Note that it is paired with mmc_gpiod_free_cd() not
 * mmc_gpio_free_cd().  Note also that it must be called prior to mmc_add_host()
 * otherwise the caller must also call mmc_gpiod_request_cd_irq().
 *
 * Returns zero on success, else an error.
 */
int mmc_gpiod_request_cd(struct mmc_host *host, const char *con_id,
			 unsigned int idx, bool override_active_level,
			 unsigned int debounce, bool *gpio_invert)
{
	struct mmc_gpio *ctx;
	struct gpio_desc *desc;
	int ret;

	ret = mmc_gpio_alloc(host);
	if (ret < 0)
		return ret;

	ctx = host->slot.handler_priv;

	if (!con_id)
		con_id = ctx->cd_label;

	desc = devm_gpiod_get_index(host->parent, con_id, idx, GPIOD_IN);
	if (IS_ERR(desc))
		return PTR_ERR(desc);

	if (debounce) {
		ret = gpiod_set_debounce(desc, debounce);
		if (ret < 0)
			return ret;
	}

	if (gpio_invert)
		*gpio_invert = !gpiod_is_active_low(desc);

	ctx->override_cd_active_level = override_active_level;
	ctx->cd_gpio = desc;

	return 0;
}
EXPORT_SYMBOL(mmc_gpiod_request_cd);

/**
 * mmc_gpiod_request_ro - request a gpio descriptor for write protection
 * @host: mmc host
 * @con_id: function within the GPIO consumer
 * @idx: index of the GPIO to obtain in the consumer
 * @override_active_level: ignore %GPIO_ACTIVE_LOW flag
 * @debounce: debounce time in microseconds
 * @gpio_invert: will return whether the GPIO line is inverted or not,
 * set to NULL to ignore
 *
 * Use this function in place of mmc_gpio_request_ro() to use the GPIO
 * descriptor API.  Note that it is paired with mmc_gpiod_free_ro() not
 * mmc_gpio_free_ro().
 *
 * Returns zero on success, else an error.
 */
int mmc_gpiod_request_ro(struct mmc_host *host, const char *con_id,
			 unsigned int idx, bool override_active_level,
			 unsigned int debounce, bool *gpio_invert)
{
	struct mmc_gpio *ctx;
	struct gpio_desc *desc;
	int ret;

	ret = mmc_gpio_alloc(host);
	if (ret < 0)
		return ret;

	ctx = host->slot.handler_priv;

	if (!con_id)
		con_id = ctx->ro_label;

	desc = devm_gpiod_get_index(host->parent, con_id, idx, GPIOD_IN);
	if (IS_ERR(desc))
		return PTR_ERR(desc);

	if (debounce) {
		ret = gpiod_set_debounce(desc, debounce);
		if (ret < 0)
			return ret;
	}

	if (gpio_invert)
		*gpio_invert = !gpiod_is_active_low(desc);

	ctx->override_ro_active_level = override_active_level;
	ctx->ro_gpio = desc;

	return 0;
}
EXPORT_SYMBOL(mmc_gpiod_request_ro);

/**
 * mmc_gpiod_free_cd - free the card-detection gpio descriptor
 * @host: mmc host
 *
 * It's provided only for cases that client drivers need to manually free
 * up the card-detection gpio requested by mmc_gpiod_request_cd().
 */
void mmc_gpiod_free_cd(struct mmc_host *host)
{
	struct mmc_gpio *ctx = host->slot.handler_priv;

	if (!ctx || !ctx->cd_gpio)
		return;

	if (host->slot.cd_irq >= 0) {
		devm_free_irq(&host->class_dev, host->slot.cd_irq, host);
		host->slot.cd_irq = -EINVAL;
	}

	devm_gpiod_put(host->parent, ctx->cd_gpio);

	ctx->cd_gpio = NULL;
}
EXPORT_SYMBOL(mmc_gpiod_free_cd);