slot-gpio.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Generic GPIO card-detect helper
  4 *
  5 * Copyright (C) 2011, Guennadi Liakhovetski <g.liakhovetski@gmx.de>
  6 */
  7
  8#include <linux/err.h>
  9#include <linux/gpio/consumer.h>
 10#include <linux/interrupt.h>
 11#include <linux/jiffies.h>
 12#include <linux/mmc/host.h>
 13#include <linux/mmc/slot-gpio.h>
 14#include <linux/module.h>
 15#include <linux/slab.h>
 16
 17#include "slot-gpio.h"
 18
 19struct mmc_gpio {
 20	struct gpio_desc *ro_gpio;
 21	struct gpio_desc *cd_gpio;
 22	irq_handler_t cd_gpio_isr;
 23	char *ro_label;
 24	char *cd_label;
 25	u32 cd_debounce_delay_ms;
 26	int cd_irq;
 27};
 28
 29static irqreturn_t mmc_gpio_cd_irqt(int irq, void *dev_id)
 30{
 31	/* Schedule a card detection after a debounce timeout */
 32	struct mmc_host *host = dev_id;
 33	struct mmc_gpio *ctx = host->slot.handler_priv;
 34
 35	host->trigger_card_event = true;
 36	mmc_detect_change(host, msecs_to_jiffies(ctx->cd_debounce_delay_ms));
 37
 38	return IRQ_HANDLED;
 39}
 40
 41int mmc_gpio_alloc(struct mmc_host *host)
 42{
 43	const char *devname = dev_name(host->parent);
 44	struct mmc_gpio *ctx;
 45
 46	ctx = devm_kzalloc(host->parent, sizeof(*ctx), GFP_KERNEL);
 47	if (!ctx)
 48		return -ENOMEM;
 49
 50	ctx->cd_debounce_delay_ms = 200;
 51	ctx->cd_label = devm_kasprintf(host->parent, GFP_KERNEL, "%s cd", devname);
 52	if (!ctx->cd_label)
 53		return -ENOMEM;
 54	ctx->ro_label = devm_kasprintf(host->parent, GFP_KERNEL, "%s ro", devname);
 55	if (!ctx->ro_label)
 56		return -ENOMEM;
 57	ctx->cd_irq = -EINVAL;
 58	host->slot.handler_priv = ctx;
 59	host->slot.cd_irq = -EINVAL;
 60
 61	return 0;
 62}
 63
 64void mmc_gpio_set_cd_irq(struct mmc_host *host, int irq)
 65{
 66	struct mmc_gpio *ctx = host->slot.handler_priv;
 67
 68	if (!ctx || irq < 0)
 69		return;
 70
 71	ctx->cd_irq = irq;
 72}
 73EXPORT_SYMBOL(mmc_gpio_set_cd_irq);
 74
 75int mmc_gpio_get_ro(struct mmc_host *host)
 76{
 77	struct mmc_gpio *ctx = host->slot.handler_priv;
 78	int cansleep;
 79
 80	if (!ctx || !ctx->ro_gpio)
 81		return -ENOSYS;
 82
 83	cansleep = gpiod_cansleep(ctx->ro_gpio);
 84	return cansleep ?
 85		gpiod_get_value_cansleep(ctx->ro_gpio) :
 86		gpiod_get_value(ctx->ro_gpio);
 87}
 88EXPORT_SYMBOL(mmc_gpio_get_ro);
 89
 90int mmc_gpio_get_cd(struct mmc_host *host)
 91{
 92	struct mmc_gpio *ctx = host->slot.handler_priv;
 93	int cansleep;
 94
 95	if (!ctx || !ctx->cd_gpio)
 96		return -ENOSYS;
 97
 98	cansleep = gpiod_cansleep(ctx->cd_gpio);
 99	return cansleep ?
100		gpiod_get_value_cansleep(ctx->cd_gpio) :
101		gpiod_get_value(ctx->cd_gpio);
102}
103EXPORT_SYMBOL(mmc_gpio_get_cd);
104
105void mmc_gpiod_request_cd_irq(struct mmc_host *host)
106{
107	struct mmc_gpio *ctx = host->slot.handler_priv;
108	int irq = -EINVAL;
109	int ret;
110
111	if (host->slot.cd_irq >= 0 || !ctx || !ctx->cd_gpio)
112		return;
113
114	/*
115	 * Do not use IRQ if the platform prefers to poll, e.g., because that
116	 * IRQ number is already used by another unit and cannot be shared.
117	 */
118	if (ctx->cd_irq >= 0)
119		irq = ctx->cd_irq;
120	else if (!(host->caps & MMC_CAP_NEEDS_POLL))
121		irq = gpiod_to_irq(ctx->cd_gpio);
122
123	if (irq >= 0) {
124		if (!ctx->cd_gpio_isr)
125			ctx->cd_gpio_isr = mmc_gpio_cd_irqt;
126		ret = devm_request_threaded_irq(host->parent, irq,
127			NULL, ctx->cd_gpio_isr,
128			IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
129			ctx->cd_label, host);
130		if (ret < 0)
131			irq = ret;
132	}
133
134	host->slot.cd_irq = irq;
135
136	if (irq < 0)
137		host->caps |= MMC_CAP_NEEDS_POLL;
138}
139EXPORT_SYMBOL(mmc_gpiod_request_cd_irq);
140
141int mmc_gpio_set_cd_wake(struct mmc_host *host, bool on)
142{
143	int ret = 0;
144
145	if (!(host->caps & MMC_CAP_CD_WAKE) ||
146	    host->slot.cd_irq < 0 ||
147	    on == host->slot.cd_wake_enabled)
148		return 0;
149
150	if (on) {
151		ret = enable_irq_wake(host->slot.cd_irq);
152		host->slot.cd_wake_enabled = !ret;
153	} else {
154		disable_irq_wake(host->slot.cd_irq);
155		host->slot.cd_wake_enabled = false;
156	}
157
158	return ret;
159}
160EXPORT_SYMBOL(mmc_gpio_set_cd_wake);
161
162/**
163 * mmc_gpiod_request_cd - request a gpio descriptor for card-detection
164 * @host: mmc host
165 * @con_id: function within the GPIO consumer
166 * @idx: index of the GPIO to obtain in the consumer
167 * @override_active_level: ignore %GPIO_ACTIVE_LOW flag
168 * @debounce: debounce time in microseconds
169 *
170 * Note that this must be called prior to mmc_add_host()
171 * otherwise the caller must also call mmc_gpiod_request_cd_irq().
172 *
173 * Returns zero on success, else an error.
174 */
175int mmc_gpiod_request_cd(struct mmc_host *host, const char *con_id,
176			 unsigned int idx, bool override_active_level,
177			 unsigned int debounce)
178{
179	struct mmc_gpio *ctx = host->slot.handler_priv;
180	struct gpio_desc *desc;
181	int ret;
182
183	desc = devm_gpiod_get_index(host->parent, con_id, idx, GPIOD_IN);
184	if (IS_ERR(desc))
185		return PTR_ERR(desc);
186
187	/* Update default label if no con_id provided */
188	if (!con_id)
189		gpiod_set_consumer_name(desc, ctx->cd_label);
190
191	if (debounce) {
192		ret = gpiod_set_debounce(desc, debounce);
193		if (ret < 0)
194			ctx->cd_debounce_delay_ms = debounce / 1000;
195	}
196
197	/* override forces default (active-low) polarity ... */
198	if (override_active_level && !gpiod_is_active_low(desc))
199		gpiod_toggle_active_low(desc);
200
201	/* ... or active-high */
202	if (host->caps2 & MMC_CAP2_CD_ACTIVE_HIGH)
203		gpiod_toggle_active_low(desc);
204
205	ctx->cd_gpio = desc;
206
207	return 0;
208}
209EXPORT_SYMBOL(mmc_gpiod_request_cd);
210
211/**
212 * mmc_gpiod_set_cd_config - set config for card-detection GPIO
213 * @host: mmc host
214 * @config: Generic pinconf config (from pinconf_to_config_packed())
215 *
216 * This can be used by mmc host drivers to fixup a card-detection GPIO's config
217 * (e.g. set PIN_CONFIG_BIAS_PULL_UP) after acquiring the GPIO descriptor
218 * through mmc_gpiod_request_cd().
219 *
220 * Returns:
221 * 0 on success, or a negative errno value on error.
222 */
223int mmc_gpiod_set_cd_config(struct mmc_host *host, unsigned long config)
224{
225	struct mmc_gpio *ctx = host->slot.handler_priv;
226
227	return gpiod_set_config(ctx->cd_gpio, config);
228}
229EXPORT_SYMBOL(mmc_gpiod_set_cd_config);
230
231bool mmc_host_can_gpio_cd(struct mmc_host *host)
232{
233	struct mmc_gpio *ctx = host->slot.handler_priv;
234
235	return ctx->cd_gpio ? true : false;
236}
237EXPORT_SYMBOL(mmc_host_can_gpio_cd);
238
239/**
240 * mmc_gpiod_request_ro - request a gpio descriptor for write protection
241 * @host: mmc host
242 * @con_id: function within the GPIO consumer
243 * @idx: index of the GPIO to obtain in the consumer
244 * @debounce: debounce time in microseconds
245 *
246 * Returns zero on success, else an error.
247 */
248int mmc_gpiod_request_ro(struct mmc_host *host, const char *con_id,
249			 unsigned int idx, unsigned int debounce)
250{
251	struct mmc_gpio *ctx = host->slot.handler_priv;
252	struct gpio_desc *desc;
253	int ret;
254
255	desc = devm_gpiod_get_index(host->parent, con_id, idx, GPIOD_IN);
256	if (IS_ERR(desc))
257		return PTR_ERR(desc);
258
259	/* Update default label if no con_id provided */
260	if (!con_id)
261		gpiod_set_consumer_name(desc, ctx->ro_label);
262
263	if (debounce) {
264		ret = gpiod_set_debounce(desc, debounce);
265		if (ret < 0)
266			return ret;
267	}
268
269	if (host->caps2 & MMC_CAP2_RO_ACTIVE_HIGH)
270		gpiod_toggle_active_low(desc);
271
272	ctx->ro_gpio = desc;
273
274	return 0;
275}
276EXPORT_SYMBOL(mmc_gpiod_request_ro);
277
278bool mmc_host_can_gpio_ro(struct mmc_host *host)
279{
280	struct mmc_gpio *ctx = host->slot.handler_priv;
281
282	return ctx->ro_gpio ? true : false;
283}
284EXPORT_SYMBOL(mmc_host_can_gpio_ro);