xref: /openbmc/linux/drivers/mmc/core/slot-gpio.c (revision 22d55f02)
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 
19 struct mmc_gpio {
20 	struct gpio_desc *ro_gpio;
21 	struct gpio_desc *cd_gpio;
22 	bool override_cd_active_level;
23 	irqreturn_t (*cd_gpio_isr)(int irq, void *dev_id);
24 	char *ro_label;
25 	char *cd_label;
26 	u32 cd_debounce_delay_ms;
27 };
28 
29 static 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 
41 int mmc_gpio_alloc(struct mmc_host *host)
42 {
43 	struct mmc_gpio *ctx = devm_kzalloc(host->parent,
44 					    sizeof(*ctx), GFP_KERNEL);
45 
46 	if (ctx) {
47 		ctx->cd_debounce_delay_ms = 200;
48 		ctx->cd_label = devm_kasprintf(host->parent, GFP_KERNEL,
49 				"%s cd", dev_name(host->parent));
50 		if (!ctx->cd_label)
51 			return -ENOMEM;
52 		ctx->ro_label = devm_kasprintf(host->parent, GFP_KERNEL,
53 				"%s ro", dev_name(host->parent));
54 		if (!ctx->ro_label)
55 			return -ENOMEM;
56 		host->slot.handler_priv = ctx;
57 		host->slot.cd_irq = -EINVAL;
58 	}
59 
60 	return ctx ? 0 : -ENOMEM;
61 }
62 
63 int mmc_gpio_get_ro(struct mmc_host *host)
64 {
65 	struct mmc_gpio *ctx = host->slot.handler_priv;
66 
67 	if (!ctx || !ctx->ro_gpio)
68 		return -ENOSYS;
69 
70 	return gpiod_get_value_cansleep(ctx->ro_gpio);
71 }
72 EXPORT_SYMBOL(mmc_gpio_get_ro);
73 
74 int mmc_gpio_get_cd(struct mmc_host *host)
75 {
76 	struct mmc_gpio *ctx = host->slot.handler_priv;
77 	int cansleep;
78 
79 	if (!ctx || !ctx->cd_gpio)
80 		return -ENOSYS;
81 
82 	cansleep = gpiod_cansleep(ctx->cd_gpio);
83 	if (ctx->override_cd_active_level) {
84 		int value = cansleep ?
85 				gpiod_get_raw_value_cansleep(ctx->cd_gpio) :
86 				gpiod_get_raw_value(ctx->cd_gpio);
87 		return !value ^ !!(host->caps2 & MMC_CAP2_CD_ACTIVE_HIGH);
88 	}
89 
90 	return cansleep ?
91 		gpiod_get_value_cansleep(ctx->cd_gpio) :
92 		gpiod_get_value(ctx->cd_gpio);
93 }
94 EXPORT_SYMBOL(mmc_gpio_get_cd);
95 
96 void mmc_gpiod_request_cd_irq(struct mmc_host *host)
97 {
98 	struct mmc_gpio *ctx = host->slot.handler_priv;
99 	int irq = -EINVAL;
100 	int ret;
101 
102 	if (host->slot.cd_irq >= 0 || !ctx || !ctx->cd_gpio)
103 		return;
104 
105 	/*
106 	 * Do not use IRQ if the platform prefers to poll, e.g., because that
107 	 * IRQ number is already used by another unit and cannot be shared.
108 	 */
109 	if (!(host->caps & MMC_CAP_NEEDS_POLL))
110 		irq = gpiod_to_irq(ctx->cd_gpio);
111 
112 	if (irq >= 0) {
113 		if (!ctx->cd_gpio_isr)
114 			ctx->cd_gpio_isr = mmc_gpio_cd_irqt;
115 		ret = devm_request_threaded_irq(host->parent, irq,
116 			NULL, ctx->cd_gpio_isr,
117 			IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
118 			ctx->cd_label, host);
119 		if (ret < 0)
120 			irq = ret;
121 	}
122 
123 	host->slot.cd_irq = irq;
124 
125 	if (irq < 0)
126 		host->caps |= MMC_CAP_NEEDS_POLL;
127 }
128 EXPORT_SYMBOL(mmc_gpiod_request_cd_irq);
129 
130 int mmc_gpio_set_cd_wake(struct mmc_host *host, bool on)
131 {
132 	int ret = 0;
133 
134 	if (!(host->caps & MMC_CAP_CD_WAKE) ||
135 	    host->slot.cd_irq < 0 ||
136 	    on == host->slot.cd_wake_enabled)
137 		return 0;
138 
139 	if (on) {
140 		ret = enable_irq_wake(host->slot.cd_irq);
141 		host->slot.cd_wake_enabled = !ret;
142 	} else {
143 		disable_irq_wake(host->slot.cd_irq);
144 		host->slot.cd_wake_enabled = false;
145 	}
146 
147 	return ret;
148 }
149 EXPORT_SYMBOL(mmc_gpio_set_cd_wake);
150 
151 /* Register an alternate interrupt service routine for
152  * the card-detect GPIO.
153  */
154 void mmc_gpio_set_cd_isr(struct mmc_host *host,
155 			 irqreturn_t (*isr)(int irq, void *dev_id))
156 {
157 	struct mmc_gpio *ctx = host->slot.handler_priv;
158 
159 	WARN_ON(ctx->cd_gpio_isr);
160 	ctx->cd_gpio_isr = isr;
161 }
162 EXPORT_SYMBOL(mmc_gpio_set_cd_isr);
163 
164 /**
165  * mmc_gpiod_request_cd - request a gpio descriptor for card-detection
166  * @host: mmc host
167  * @con_id: function within the GPIO consumer
168  * @idx: index of the GPIO to obtain in the consumer
169  * @override_active_level: ignore %GPIO_ACTIVE_LOW flag
170  * @debounce: debounce time in microseconds
171  * @gpio_invert: will return whether the GPIO line is inverted or not, set
172  * to NULL to ignore
173  *
174  * Note that this must be called prior to mmc_add_host()
175  * otherwise the caller must also call mmc_gpiod_request_cd_irq().
176  *
177  * Returns zero on success, else an error.
178  */
179 int mmc_gpiod_request_cd(struct mmc_host *host, const char *con_id,
180 			 unsigned int idx, bool override_active_level,
181 			 unsigned int debounce, bool *gpio_invert)
182 {
183 	struct mmc_gpio *ctx = host->slot.handler_priv;
184 	struct gpio_desc *desc;
185 	int ret;
186 
187 	desc = devm_gpiod_get_index(host->parent, con_id, idx, GPIOD_IN);
188 	if (IS_ERR(desc))
189 		return PTR_ERR(desc);
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 	if (gpio_invert)
198 		*gpio_invert = !gpiod_is_active_low(desc);
199 
200 	ctx->override_cd_active_level = override_active_level;
201 	ctx->cd_gpio = desc;
202 
203 	return 0;
204 }
205 EXPORT_SYMBOL(mmc_gpiod_request_cd);
206 
207 bool mmc_can_gpio_cd(struct mmc_host *host)
208 {
209 	struct mmc_gpio *ctx = host->slot.handler_priv;
210 
211 	return ctx->cd_gpio ? true : false;
212 }
213 EXPORT_SYMBOL(mmc_can_gpio_cd);
214 
215 /**
216  * mmc_gpiod_request_ro - request a gpio descriptor for write protection
217  * @host: mmc host
218  * @con_id: function within the GPIO consumer
219  * @idx: index of the GPIO to obtain in the consumer
220  * @debounce: debounce time in microseconds
221  * @gpio_invert: will return whether the GPIO line is inverted or not,
222  * set to NULL to ignore
223  *
224  * Returns zero on success, else an error.
225  */
226 int mmc_gpiod_request_ro(struct mmc_host *host, const char *con_id,
227 			 unsigned int idx,
228 			 unsigned int debounce, bool *gpio_invert)
229 {
230 	struct mmc_gpio *ctx = host->slot.handler_priv;
231 	struct gpio_desc *desc;
232 	int ret;
233 
234 	desc = devm_gpiod_get_index(host->parent, con_id, idx, GPIOD_IN);
235 	if (IS_ERR(desc))
236 		return PTR_ERR(desc);
237 
238 	if (debounce) {
239 		ret = gpiod_set_debounce(desc, debounce);
240 		if (ret < 0)
241 			return ret;
242 	}
243 
244 	if (gpio_invert)
245 		*gpio_invert = !gpiod_is_active_low(desc);
246 
247 	ctx->ro_gpio = desc;
248 
249 	return 0;
250 }
251 EXPORT_SYMBOL(mmc_gpiod_request_ro);
252 
253 bool mmc_can_gpio_ro(struct mmc_host *host)
254 {
255 	struct mmc_gpio *ctx = host->slot.handler_priv;
256 
257 	return ctx->ro_gpio ? true : false;
258 }
259 EXPORT_SYMBOL(mmc_can_gpio_ro);
260