xref: /linux/drivers/mmc/core/slot-gpio.c (revision 827634added7f38b7d724cab1dccdb2b004c13c3)
1 /*
2  * Generic GPIO card-detect helper
3  *
4  * Copyright (C) 2011, Guennadi Liakhovetski <g.liakhovetski@gmx.de>
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License version 2 as
8  * published by the Free Software Foundation.
9  */
10 
11 #include <linux/err.h>
12 #include <linux/gpio.h>
13 #include <linux/gpio/consumer.h>
14 #include <linux/interrupt.h>
15 #include <linux/jiffies.h>
16 #include <linux/mmc/host.h>
17 #include <linux/mmc/slot-gpio.h>
18 #include <linux/module.h>
19 #include <linux/slab.h>
20 
21 #include "slot-gpio.h"
22 
23 struct mmc_gpio {
24 	struct gpio_desc *ro_gpio;
25 	struct gpio_desc *cd_gpio;
26 	bool override_ro_active_level;
27 	bool override_cd_active_level;
28 	irqreturn_t (*cd_gpio_isr)(int irq, void *dev_id);
29 	char *ro_label;
30 	char cd_label[0];
31 };
32 
33 static irqreturn_t mmc_gpio_cd_irqt(int irq, void *dev_id)
34 {
35 	/* Schedule a card detection after a debounce timeout */
36 	struct mmc_host *host = dev_id;
37 
38 	host->trigger_card_event = true;
39 	mmc_detect_change(host, msecs_to_jiffies(200));
40 
41 	return IRQ_HANDLED;
42 }
43 
44 int mmc_gpio_alloc(struct mmc_host *host)
45 {
46 	size_t len = strlen(dev_name(host->parent)) + 4;
47 	struct mmc_gpio *ctx = devm_kzalloc(host->parent,
48 				sizeof(*ctx) + 2 * len,	GFP_KERNEL);
49 
50 	if (ctx) {
51 		ctx->ro_label = ctx->cd_label + len;
52 		snprintf(ctx->cd_label, len, "%s cd", dev_name(host->parent));
53 		snprintf(ctx->ro_label, len, "%s ro", dev_name(host->parent));
54 		host->slot.handler_priv = ctx;
55 		host->slot.cd_irq = -EINVAL;
56 	}
57 
58 	return ctx ? 0 : -ENOMEM;
59 }
60 
61 int mmc_gpio_get_ro(struct mmc_host *host)
62 {
63 	struct mmc_gpio *ctx = host->slot.handler_priv;
64 
65 	if (!ctx || !ctx->ro_gpio)
66 		return -ENOSYS;
67 
68 	if (ctx->override_ro_active_level)
69 		return !gpiod_get_raw_value_cansleep(ctx->ro_gpio) ^
70 			!!(host->caps2 & MMC_CAP2_RO_ACTIVE_HIGH);
71 
72 	return gpiod_get_value_cansleep(ctx->ro_gpio);
73 }
74 EXPORT_SYMBOL(mmc_gpio_get_ro);
75 
76 int mmc_gpio_get_cd(struct mmc_host *host)
77 {
78 	struct mmc_gpio *ctx = host->slot.handler_priv;
79 
80 	if (!ctx || !ctx->cd_gpio)
81 		return -ENOSYS;
82 
83 	if (ctx->override_cd_active_level)
84 		return !gpiod_get_raw_value_cansleep(ctx->cd_gpio) ^
85 			!!(host->caps2 & MMC_CAP2_CD_ACTIVE_HIGH);
86 
87 	return gpiod_get_value_cansleep(ctx->cd_gpio);
88 }
89 EXPORT_SYMBOL(mmc_gpio_get_cd);
90 
91 /**
92  * mmc_gpio_request_ro - request a gpio for write-protection
93  * @host: mmc host
94  * @gpio: gpio number requested
95  *
96  * As devm_* managed functions are used in mmc_gpio_request_ro(), client
97  * drivers do not need to worry about freeing up memory.
98  *
99  * Returns zero on success, else an error.
100  */
101 int mmc_gpio_request_ro(struct mmc_host *host, unsigned int gpio)
102 {
103 	struct mmc_gpio *ctx = host->slot.handler_priv;
104 	int ret;
105 
106 	if (!gpio_is_valid(gpio))
107 		return -EINVAL;
108 
109 	ret = devm_gpio_request_one(host->parent, gpio, GPIOF_DIR_IN,
110 				    ctx->ro_label);
111 	if (ret < 0)
112 		return ret;
113 
114 	ctx->override_ro_active_level = true;
115 	ctx->ro_gpio = gpio_to_desc(gpio);
116 
117 	return 0;
118 }
119 EXPORT_SYMBOL(mmc_gpio_request_ro);
120 
121 void mmc_gpiod_request_cd_irq(struct mmc_host *host)
122 {
123 	struct mmc_gpio *ctx = host->slot.handler_priv;
124 	int ret, irq;
125 
126 	if (host->slot.cd_irq >= 0 || !ctx || !ctx->cd_gpio)
127 		return;
128 
129 	irq = gpiod_to_irq(ctx->cd_gpio);
130 
131 	/*
132 	 * Even if gpiod_to_irq() returns a valid IRQ number, the platform might
133 	 * still prefer to poll, e.g., because that IRQ number is already used
134 	 * by another unit and cannot be shared.
135 	 */
136 	if (irq >= 0 && host->caps & MMC_CAP_NEEDS_POLL)
137 		irq = -EINVAL;
138 
139 	if (irq >= 0) {
140 		if (!ctx->cd_gpio_isr)
141 			ctx->cd_gpio_isr = mmc_gpio_cd_irqt;
142 		ret = devm_request_threaded_irq(host->parent, irq,
143 			NULL, ctx->cd_gpio_isr,
144 			IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
145 			ctx->cd_label, host);
146 		if (ret < 0)
147 			irq = ret;
148 	}
149 
150 	host->slot.cd_irq = irq;
151 
152 	if (irq < 0)
153 		host->caps |= MMC_CAP_NEEDS_POLL;
154 }
155 EXPORT_SYMBOL(mmc_gpiod_request_cd_irq);
156 
157 /* Register an alternate interrupt service routine for
158  * the card-detect GPIO.
159  */
160 void mmc_gpio_set_cd_isr(struct mmc_host *host,
161 			 irqreturn_t (*isr)(int irq, void *dev_id))
162 {
163 	struct mmc_gpio *ctx = host->slot.handler_priv;
164 
165 	WARN_ON(ctx->cd_gpio_isr);
166 	ctx->cd_gpio_isr = isr;
167 }
168 EXPORT_SYMBOL(mmc_gpio_set_cd_isr);
169 
170 /**
171  * mmc_gpio_request_cd - request a gpio for card-detection
172  * @host: mmc host
173  * @gpio: gpio number requested
174  * @debounce: debounce time in microseconds
175  *
176  * As devm_* managed functions are used in mmc_gpio_request_cd(), client
177  * drivers do not need to worry about freeing up memory.
178  *
179  * If GPIO debouncing is desired, set the debounce parameter to a non-zero
180  * value. The caller is responsible for ensuring that the GPIO driver associated
181  * with the GPIO supports debouncing, otherwise an error will be returned.
182  *
183  * Returns zero on success, else an error.
184  */
185 int mmc_gpio_request_cd(struct mmc_host *host, unsigned int gpio,
186 			unsigned int debounce)
187 {
188 	struct mmc_gpio *ctx = host->slot.handler_priv;
189 	int ret;
190 
191 	ret = devm_gpio_request_one(host->parent, gpio, GPIOF_DIR_IN,
192 				    ctx->cd_label);
193 	if (ret < 0)
194 		/*
195 		 * don't bother freeing memory. It might still get used by other
196 		 * slot functions, in any case it will be freed, when the device
197 		 * is destroyed.
198 		 */
199 		return ret;
200 
201 	if (debounce) {
202 		ret = gpio_set_debounce(gpio, debounce);
203 		if (ret < 0)
204 			return ret;
205 	}
206 
207 	ctx->override_cd_active_level = true;
208 	ctx->cd_gpio = gpio_to_desc(gpio);
209 
210 	return 0;
211 }
212 EXPORT_SYMBOL(mmc_gpio_request_cd);
213 
214 /**
215  * mmc_gpiod_request_cd - request a gpio descriptor for card-detection
216  * @host: mmc host
217  * @con_id: function within the GPIO consumer
218  * @idx: index of the GPIO to obtain in the consumer
219  * @override_active_level: ignore %GPIO_ACTIVE_LOW flag
220  * @debounce: debounce time in microseconds
221  * @gpio_invert: will return whether the GPIO line is inverted or not, set
222  * to NULL to ignore
223  *
224  * Use this function in place of mmc_gpio_request_cd() to use the GPIO
225  * descriptor API.  Note that it must be called prior to mmc_add_host()
226  * otherwise the caller must also call mmc_gpiod_request_cd_irq().
227  *
228  * Returns zero on success, else an error.
229  */
230 int mmc_gpiod_request_cd(struct mmc_host *host, const char *con_id,
231 			 unsigned int idx, bool override_active_level,
232 			 unsigned int debounce, bool *gpio_invert)
233 {
234 	struct mmc_gpio *ctx = host->slot.handler_priv;
235 	struct gpio_desc *desc;
236 	int ret;
237 
238 	if (!con_id)
239 		con_id = ctx->cd_label;
240 
241 	desc = devm_gpiod_get_index(host->parent, con_id, idx, GPIOD_IN);
242 	if (IS_ERR(desc))
243 		return PTR_ERR(desc);
244 
245 	if (debounce) {
246 		ret = gpiod_set_debounce(desc, debounce);
247 		if (ret < 0)
248 			return ret;
249 	}
250 
251 	if (gpio_invert)
252 		*gpio_invert = !gpiod_is_active_low(desc);
253 
254 	ctx->override_cd_active_level = override_active_level;
255 	ctx->cd_gpio = desc;
256 
257 	return 0;
258 }
259 EXPORT_SYMBOL(mmc_gpiod_request_cd);
260 
261 /**
262  * mmc_gpiod_request_ro - request a gpio descriptor for write protection
263  * @host: mmc host
264  * @con_id: function within the GPIO consumer
265  * @idx: index of the GPIO to obtain in the consumer
266  * @override_active_level: ignore %GPIO_ACTIVE_LOW flag
267  * @debounce: debounce time in microseconds
268  * @gpio_invert: will return whether the GPIO line is inverted or not,
269  * set to NULL to ignore
270  *
271  * Use this function in place of mmc_gpio_request_ro() to use the GPIO
272  * descriptor API.
273  *
274  * Returns zero on success, else an error.
275  */
276 int mmc_gpiod_request_ro(struct mmc_host *host, const char *con_id,
277 			 unsigned int idx, bool override_active_level,
278 			 unsigned int debounce, bool *gpio_invert)
279 {
280 	struct mmc_gpio *ctx = host->slot.handler_priv;
281 	struct gpio_desc *desc;
282 	int ret;
283 
284 	if (!con_id)
285 		con_id = ctx->ro_label;
286 
287 	desc = devm_gpiod_get_index(host->parent, con_id, idx, GPIOD_IN);
288 	if (IS_ERR(desc))
289 		return PTR_ERR(desc);
290 
291 	if (debounce) {
292 		ret = gpiod_set_debounce(desc, debounce);
293 		if (ret < 0)
294 			return ret;
295 	}
296 
297 	if (gpio_invert)
298 		*gpio_invert = !gpiod_is_active_low(desc);
299 
300 	ctx->override_ro_active_level = override_active_level;
301 	ctx->ro_gpio = desc;
302 
303 	return 0;
304 }
305 EXPORT_SYMBOL(mmc_gpiod_request_ro);
306