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
 23struct 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
 33static 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
 44int 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
 61int 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}
 74EXPORT_SYMBOL(mmc_gpio_get_ro);
 75
 76int 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}
 89EXPORT_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 */
101int 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}
119EXPORT_SYMBOL(mmc_gpio_request_ro);
120
121void 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}
155EXPORT_SYMBOL(mmc_gpiod_request_cd_irq);
156
157/* Register an alternate interrupt service routine for
158 * the card-detect GPIO.
159 */
160void 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}
168EXPORT_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 */
185int 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}
212EXPORT_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 */
230int 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}
259EXPORT_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 */
276int 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}
305EXPORT_SYMBOL(mmc_gpiod_request_ro);