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/cd-gpio.h>
16#include <linux/mmc/host.h>
17#include <linux/module.h>
18#include <linux/slab.h>
19
20struct mmc_cd_gpio {
21	unsigned int gpio;
22	char label[0];
23};
24
25static irqreturn_t mmc_cd_gpio_irqt(int irq, void *dev_id)
26{
27	/* Schedule a card detection after a debounce timeout */
28	mmc_detect_change(dev_id, msecs_to_jiffies(100));
29	return IRQ_HANDLED;
30}
31
32int mmc_cd_gpio_request(struct mmc_host *host, unsigned int gpio)
33{
34	size_t len = strlen(dev_name(host->parent)) + 4;
35	struct mmc_cd_gpio *cd;
36	int irq = gpio_to_irq(gpio);
37	int ret;
38
39	if (irq < 0)
40		return irq;
41
42	cd = kmalloc(sizeof(*cd) + len, GFP_KERNEL);
43	if (!cd)
44		return -ENOMEM;
45
46	snprintf(cd->label, len, "%s cd", dev_name(host->parent));
47
48	ret = gpio_request_one(gpio, GPIOF_DIR_IN, cd->label);
49	if (ret < 0)
50		goto egpioreq;
51
52	ret = request_threaded_irq(irq, NULL, mmc_cd_gpio_irqt,
53				   IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING |
54				   IRQF_ONESHOT, cd->label, host);
55	if (ret < 0)
56		goto eirqreq;
57
58	cd->gpio = gpio;
59	host->hotplug.irq = irq;
60	host->hotplug.handler_priv = cd;
61
62	return 0;
63
64eirqreq:
65	gpio_free(gpio);
66egpioreq:
67	kfree(cd);
68	return ret;
69}
70EXPORT_SYMBOL(mmc_cd_gpio_request);
71
72void mmc_cd_gpio_free(struct mmc_host *host)
73{
74	struct mmc_cd_gpio *cd = host->hotplug.handler_priv;
75
76	if (!cd)
77		return;
78
79	free_irq(host->hotplug.irq, host);
80	gpio_free(cd->gpio);
81	kfree(cd);
82}
83EXPORT_SYMBOL(mmc_cd_gpio_free);