xref: /linux/drivers/mmc/core/slot-gpio.c (revision b889fcf63cb62e7fdb7816565e28f44dbe4a76a5)
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/interrupt.h>
14 #include <linux/jiffies.h>
15 #include <linux/mmc/host.h>
16 #include <linux/mmc/slot-gpio.h>
17 #include <linux/module.h>
18 #include <linux/slab.h>
19 
20 struct mmc_gpio {
21 	int ro_gpio;
22 	int cd_gpio;
23 	char *ro_label;
24 	char cd_label[0];
25 };
26 
27 static irqreturn_t mmc_gpio_cd_irqt(int irq, void *dev_id)
28 {
29 	/* Schedule a card detection after a debounce timeout */
30 	struct mmc_host *host = dev_id;
31 
32 	if (host->ops->card_event)
33 		host->ops->card_event(host);
34 
35 	mmc_detect_change(host, msecs_to_jiffies(200));
36 
37 	return IRQ_HANDLED;
38 }
39 
40 static int mmc_gpio_alloc(struct mmc_host *host)
41 {
42 	size_t len = strlen(dev_name(host->parent)) + 4;
43 	struct mmc_gpio *ctx;
44 
45 	mutex_lock(&host->slot.lock);
46 
47 	ctx = host->slot.handler_priv;
48 	if (!ctx) {
49 		/*
50 		 * devm_kzalloc() can be called after device_initialize(), even
51 		 * before device_add(), i.e., between mmc_alloc_host() and
52 		 * mmc_add_host()
53 		 */
54 		ctx = devm_kzalloc(&host->class_dev, sizeof(*ctx) + 2 * len,
55 				   GFP_KERNEL);
56 		if (ctx) {
57 			ctx->ro_label = ctx->cd_label + len;
58 			snprintf(ctx->cd_label, len, "%s cd", dev_name(host->parent));
59 			snprintf(ctx->ro_label, len, "%s ro", dev_name(host->parent));
60 			ctx->cd_gpio = -EINVAL;
61 			ctx->ro_gpio = -EINVAL;
62 			host->slot.handler_priv = ctx;
63 		}
64 	}
65 
66 	mutex_unlock(&host->slot.lock);
67 
68 	return ctx ? 0 : -ENOMEM;
69 }
70 
71 int mmc_gpio_get_ro(struct mmc_host *host)
72 {
73 	struct mmc_gpio *ctx = host->slot.handler_priv;
74 
75 	if (!ctx || !gpio_is_valid(ctx->ro_gpio))
76 		return -ENOSYS;
77 
78 	return !gpio_get_value_cansleep(ctx->ro_gpio) ^
79 		!!(host->caps2 & MMC_CAP2_RO_ACTIVE_HIGH);
80 }
81 EXPORT_SYMBOL(mmc_gpio_get_ro);
82 
83 int mmc_gpio_get_cd(struct mmc_host *host)
84 {
85 	struct mmc_gpio *ctx = host->slot.handler_priv;
86 
87 	if (!ctx || !gpio_is_valid(ctx->cd_gpio))
88 		return -ENOSYS;
89 
90 	return !gpio_get_value_cansleep(ctx->cd_gpio) ^
91 		!!(host->caps2 & MMC_CAP2_CD_ACTIVE_HIGH);
92 }
93 EXPORT_SYMBOL(mmc_gpio_get_cd);
94 
95 int mmc_gpio_request_ro(struct mmc_host *host, unsigned int gpio)
96 {
97 	struct mmc_gpio *ctx;
98 	int ret;
99 
100 	if (!gpio_is_valid(gpio))
101 		return -EINVAL;
102 
103 	ret = mmc_gpio_alloc(host);
104 	if (ret < 0)
105 		return ret;
106 
107 	ctx = host->slot.handler_priv;
108 
109 	ret = gpio_request_one(gpio, GPIOF_DIR_IN, ctx->ro_label);
110 	if (ret < 0)
111 		return ret;
112 
113 	ctx->ro_gpio = gpio;
114 
115 	return 0;
116 }
117 EXPORT_SYMBOL(mmc_gpio_request_ro);
118 
119 int mmc_gpio_request_cd(struct mmc_host *host, unsigned int gpio)
120 {
121 	struct mmc_gpio *ctx;
122 	int irq = gpio_to_irq(gpio);
123 	int ret;
124 
125 	ret = mmc_gpio_alloc(host);
126 	if (ret < 0)
127 		return ret;
128 
129 	ctx = host->slot.handler_priv;
130 
131 	ret = gpio_request_one(gpio, GPIOF_DIR_IN, ctx->cd_label);
132 	if (ret < 0)
133 		/*
134 		 * don't bother freeing memory. It might still get used by other
135 		 * slot functions, in any case it will be freed, when the device
136 		 * is destroyed.
137 		 */
138 		return ret;
139 
140 	/*
141 	 * Even if gpio_to_irq() returns a valid IRQ number, the platform might
142 	 * still prefer to poll, e.g., because that IRQ number is already used
143 	 * by another unit and cannot be shared.
144 	 */
145 	if (irq >= 0 && host->caps & MMC_CAP_NEEDS_POLL)
146 		irq = -EINVAL;
147 
148 	if (irq >= 0) {
149 		ret = request_threaded_irq(irq, NULL, mmc_gpio_cd_irqt,
150 			IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
151 			ctx->cd_label, host);
152 		if (ret < 0)
153 			irq = ret;
154 	}
155 
156 	host->slot.cd_irq = irq;
157 
158 	if (irq < 0)
159 		host->caps |= MMC_CAP_NEEDS_POLL;
160 
161 	ctx->cd_gpio = gpio;
162 
163 	return 0;
164 }
165 EXPORT_SYMBOL(mmc_gpio_request_cd);
166 
167 void mmc_gpio_free_ro(struct mmc_host *host)
168 {
169 	struct mmc_gpio *ctx = host->slot.handler_priv;
170 	int gpio;
171 
172 	if (!ctx || !gpio_is_valid(ctx->ro_gpio))
173 		return;
174 
175 	gpio = ctx->ro_gpio;
176 	ctx->ro_gpio = -EINVAL;
177 
178 	gpio_free(gpio);
179 }
180 EXPORT_SYMBOL(mmc_gpio_free_ro);
181 
182 void mmc_gpio_free_cd(struct mmc_host *host)
183 {
184 	struct mmc_gpio *ctx = host->slot.handler_priv;
185 	int gpio;
186 
187 	if (!ctx || !gpio_is_valid(ctx->cd_gpio))
188 		return;
189 
190 	if (host->slot.cd_irq >= 0) {
191 		free_irq(host->slot.cd_irq, host);
192 		host->slot.cd_irq = -EINVAL;
193 	}
194 
195 	gpio = ctx->cd_gpio;
196 	ctx->cd_gpio = -EINVAL;
197 
198 	gpio_free(gpio);
199 }
200 EXPORT_SYMBOL(mmc_gpio_free_cd);
201