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
mmc_gpio_cd_irqt(int irq,void * dev_id)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
mmc_gpio_alloc(struct mmc_host * host)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
mmc_gpio_get_ro(struct mmc_host * host)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
mmc_gpio_get_cd(struct mmc_host * host)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 /**
96 * mmc_gpio_request_ro - request a gpio for write-protection
97 * @host: mmc host
98 * @gpio: gpio number requested
99 *
100 * As devm_* managed functions are used in mmc_gpio_request_ro(), client
101 * drivers do not need to explicitly call mmc_gpio_free_ro() for freeing up,
102 * if the requesting and freeing are only needed at probing and unbinding time
103 * for once. However, if client drivers do something special like runtime
104 * switching for write-protection, they are responsible for calling
105 * mmc_gpio_request_ro() and mmc_gpio_free_ro() as a pair on their own.
106 *
107 * Returns zero on success, else an error.
108 */
mmc_gpio_request_ro(struct mmc_host * host,unsigned int gpio)109 int mmc_gpio_request_ro(struct mmc_host *host, unsigned int gpio)
110 {
111 struct mmc_gpio *ctx;
112 int ret;
113
114 if (!gpio_is_valid(gpio))
115 return -EINVAL;
116
117 ret = mmc_gpio_alloc(host);
118 if (ret < 0)
119 return ret;
120
121 ctx = host->slot.handler_priv;
122
123 ret = devm_gpio_request_one(&host->class_dev, gpio, GPIOF_DIR_IN,
124 ctx->ro_label);
125 if (ret < 0)
126 return ret;
127
128 ctx->ro_gpio = gpio;
129
130 return 0;
131 }
132 EXPORT_SYMBOL(mmc_gpio_request_ro);
133
134 /**
135 * mmc_gpio_request_cd - request a gpio for card-detection
136 * @host: mmc host
137 * @gpio: gpio number requested
138 *
139 * As devm_* managed functions are used in mmc_gpio_request_cd(), client
140 * drivers do not need to explicitly call mmc_gpio_free_cd() for freeing up,
141 * if the requesting and freeing are only needed at probing and unbinding time
142 * for once. However, if client drivers do something special like runtime
143 * switching for card-detection, they are responsible for calling
144 * mmc_gpio_request_cd() and mmc_gpio_free_cd() as a pair on their own.
145 *
146 * Returns zero on success, else an error.
147 */
mmc_gpio_request_cd(struct mmc_host * host,unsigned int gpio)148 int mmc_gpio_request_cd(struct mmc_host *host, unsigned int gpio)
149 {
150 struct mmc_gpio *ctx;
151 int irq = gpio_to_irq(gpio);
152 int ret;
153
154 ret = mmc_gpio_alloc(host);
155 if (ret < 0)
156 return ret;
157
158 ctx = host->slot.handler_priv;
159
160 ret = devm_gpio_request_one(&host->class_dev, gpio, GPIOF_DIR_IN,
161 ctx->cd_label);
162 if (ret < 0)
163 /*
164 * don't bother freeing memory. It might still get used by other
165 * slot functions, in any case it will be freed, when the device
166 * is destroyed.
167 */
168 return ret;
169
170 /*
171 * Even if gpio_to_irq() returns a valid IRQ number, the platform might
172 * still prefer to poll, e.g., because that IRQ number is already used
173 * by another unit and cannot be shared.
174 */
175 if (irq >= 0 && host->caps & MMC_CAP_NEEDS_POLL)
176 irq = -EINVAL;
177
178 if (irq >= 0) {
179 ret = devm_request_threaded_irq(&host->class_dev, irq,
180 NULL, mmc_gpio_cd_irqt,
181 IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
182 ctx->cd_label, host);
183 if (ret < 0)
184 irq = ret;
185 }
186
187 host->slot.cd_irq = irq;
188
189 if (irq < 0)
190 host->caps |= MMC_CAP_NEEDS_POLL;
191
192 ctx->cd_gpio = gpio;
193
194 return 0;
195 }
196 EXPORT_SYMBOL(mmc_gpio_request_cd);
197
198 /**
199 * mmc_gpio_free_ro - free the write-protection gpio
200 * @host: mmc host
201 *
202 * It's provided only for cases that client drivers need to manually free
203 * up the write-protection gpio requested by mmc_gpio_request_ro().
204 */
mmc_gpio_free_ro(struct mmc_host * host)205 void mmc_gpio_free_ro(struct mmc_host *host)
206 {
207 struct mmc_gpio *ctx = host->slot.handler_priv;
208 int gpio;
209
210 if (!ctx || !gpio_is_valid(ctx->ro_gpio))
211 return;
212
213 gpio = ctx->ro_gpio;
214 ctx->ro_gpio = -EINVAL;
215
216 devm_gpio_free(&host->class_dev, gpio);
217 }
218 EXPORT_SYMBOL(mmc_gpio_free_ro);
219
220 /**
221 * mmc_gpio_free_cd - free the card-detection gpio
222 * @host: mmc host
223 *
224 * It's provided only for cases that client drivers need to manually free
225 * up the card-detection gpio requested by mmc_gpio_request_cd().
226 */
mmc_gpio_free_cd(struct mmc_host * host)227 void mmc_gpio_free_cd(struct mmc_host *host)
228 {
229 struct mmc_gpio *ctx = host->slot.handler_priv;
230 int gpio;
231
232 if (!ctx || !gpio_is_valid(ctx->cd_gpio))
233 return;
234
235 if (host->slot.cd_irq >= 0) {
236 devm_free_irq(&host->class_dev, host->slot.cd_irq, host);
237 host->slot.cd_irq = -EINVAL;
238 }
239
240 gpio = ctx->cd_gpio;
241 ctx->cd_gpio = -EINVAL;
242
243 devm_gpio_free(&host->class_dev, gpio);
244 }
245 EXPORT_SYMBOL(mmc_gpio_free_cd);
246