[linux-2.6-block.git] / drivers / mmc / core / pwrseq_emmc.c

/*
 * Copyright (C) 2015, Samsung Electronics Co., Ltd.
 *
 * Author: Marek Szyprowski <m.szyprowski@samsung.com>
 *
 * License terms: GNU General Public License (GPL) version 2
 *
 * Simple eMMC hardware reset provider
 */
#include <linux/delay.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/gpio/consumer.h>
#include <linux/reboot.h>

#include <linux/mmc/host.h>

#include "pwrseq.h"

struct mmc_pwrseq_emmc {
	struct mmc_pwrseq pwrseq;
	struct notifier_block reset_nb;
	struct gpio_desc *reset_gpio;
};

static void __mmc_pwrseq_emmc_reset(struct mmc_pwrseq_emmc *pwrseq)
{
	gpiod_set_value(pwrseq->reset_gpio, 1);
	udelay(1);
	gpiod_set_value(pwrseq->reset_gpio, 0);
	udelay(200);
}

static void mmc_pwrseq_emmc_reset(struct mmc_host *host)
{
	struct mmc_pwrseq_emmc *pwrseq = container_of(host->pwrseq,
					struct mmc_pwrseq_emmc, pwrseq);

	__mmc_pwrseq_emmc_reset(pwrseq);
}

static void mmc_pwrseq_emmc_free(struct mmc_host *host)
{
	struct mmc_pwrseq_emmc *pwrseq = container_of(host->pwrseq,
					struct mmc_pwrseq_emmc, pwrseq);

	unregister_restart_handler(&pwrseq->reset_nb);
	gpiod_put(pwrseq->reset_gpio);
	kfree(pwrseq);
}

static struct mmc_pwrseq_ops mmc_pwrseq_emmc_ops = {
	.post_power_on = mmc_pwrseq_emmc_reset,
	.free = mmc_pwrseq_emmc_free,
};

static int mmc_pwrseq_emmc_reset_nb(struct notifier_block *this,
				    unsigned long mode, void *cmd)
{
	struct mmc_pwrseq_emmc *pwrseq = container_of(this,
					struct mmc_pwrseq_emmc, reset_nb);

	__mmc_pwrseq_emmc_reset(pwrseq);
	return NOTIFY_DONE;
}

struct mmc_pwrseq *mmc_pwrseq_emmc_alloc(struct mmc_host *host,
					 struct device *dev)
{
	struct mmc_pwrseq_emmc *pwrseq;
	int ret = 0;

	pwrseq = kzalloc(sizeof(struct mmc_pwrseq_emmc), GFP_KERNEL);
	if (!pwrseq)
		return ERR_PTR(-ENOMEM);

	pwrseq->reset_gpio = gpiod_get_index(dev, "reset", 0, GPIOD_OUT_LOW);
	if (IS_ERR(pwrseq->reset_gpio)) {
		ret = PTR_ERR(pwrseq->reset_gpio);
		goto free;
	}

	/*
	 * register reset handler to ensure emmc reset also from
	 * emergency_reboot(), priority 129 schedules it just before
	 * system reboot
	 */
	pwrseq->reset_nb.notifier_call = mmc_pwrseq_emmc_reset_nb;
	pwrseq->reset_nb.priority = 129;
	register_restart_handler(&pwrseq->reset_nb);

	pwrseq->pwrseq.ops = &mmc_pwrseq_emmc_ops;

	return &pwrseq->pwrseq;
free:
	kfree(pwrseq);
	return ERR_PTR(ret);
}
Commit	Line	Data
726b6324 MS	1	/*
	2	* Copyright (C) 2015, Samsung Electronics Co., Ltd.
	3	*
	4	* Author: Marek Szyprowski <m.szyprowski@samsung.com>
	5	*
	6	* License terms: GNU General Public License (GPL) version 2
	7	*
	8	* Simple eMMC hardware reset provider
	9	*/
	10	#include <linux/delay.h>
	11	#include <linux/kernel.h>
	12	#include <linux/slab.h>
	13	#include <linux/device.h>
	14	#include <linux/err.h>
	15	#include <linux/gpio/consumer.h>
	16	#include <linux/reboot.h>
	17
	18	#include <linux/mmc/host.h>
	19
	20	#include "pwrseq.h"
	21
	22	struct mmc_pwrseq_emmc {
	23	struct mmc_pwrseq pwrseq;
	24	struct notifier_block reset_nb;
	25	struct gpio_desc *reset_gpio;
	26	};
	27
	28	static void __mmc_pwrseq_emmc_reset(struct mmc_pwrseq_emmc *pwrseq)
	29	{
	30	gpiod_set_value(pwrseq->reset_gpio, 1);
	31	udelay(1);
	32	gpiod_set_value(pwrseq->reset_gpio, 0);
	33	udelay(200);
	34	}
	35
	36	static void mmc_pwrseq_emmc_reset(struct mmc_host *host)
	37	{
	38	struct mmc_pwrseq_emmc *pwrseq = container_of(host->pwrseq,
	39	struct mmc_pwrseq_emmc, pwrseq);
	40
	41	__mmc_pwrseq_emmc_reset(pwrseq);
	42	}
	43
	44	static void mmc_pwrseq_emmc_free(struct mmc_host *host)
	45	{
	46	struct mmc_pwrseq_emmc *pwrseq = container_of(host->pwrseq,
	47	struct mmc_pwrseq_emmc, pwrseq);
	48
	49	unregister_restart_handler(&pwrseq->reset_nb);
	50	gpiod_put(pwrseq->reset_gpio);
	51	kfree(pwrseq);
726b6324 MS	52	}
	53
	54	static struct mmc_pwrseq_ops mmc_pwrseq_emmc_ops = {
	55	.post_power_on = mmc_pwrseq_emmc_reset,
	56	.free = mmc_pwrseq_emmc_free,
	57	};
	58
	59	static int mmc_pwrseq_emmc_reset_nb(struct notifier_block *this,
	60	unsigned long mode, void *cmd)
	61	{
	62	struct mmc_pwrseq_emmc *pwrseq = container_of(this,
	63	struct mmc_pwrseq_emmc, reset_nb);
	64
	65	__mmc_pwrseq_emmc_reset(pwrseq);
	66	return NOTIFY_DONE;
	67	}
	68
0f12a0ce AC	69	struct mmc_pwrseq mmc_pwrseq_emmc_alloc(struct mmc_host host,
0f12a0ce AC	70	struct device *dev)
726b6324 MS	71	{
	72	struct mmc_pwrseq_emmc *pwrseq;
	73	int ret = 0;
	74
	75	pwrseq = kzalloc(sizeof(struct mmc_pwrseq_emmc), GFP_KERNEL);
	76	if (!pwrseq)
0f12a0ce	77	return ERR_PTR(-ENOMEM);
726b6324 MS	78
	79	pwrseq->reset_gpio = gpiod_get_index(dev, "reset", 0, GPIOD_OUT_LOW);
	80	if (IS_ERR(pwrseq->reset_gpio)) {
	81	ret = PTR_ERR(pwrseq->reset_gpio);
	82	goto free;
	83	}
	84
	85	/*
	86	* register reset handler to ensure emmc reset also from
	87	* emergency_reboot(), priority 129 schedules it just before
	88	* system reboot
	89	*/
	90	pwrseq->reset_nb.notifier_call = mmc_pwrseq_emmc_reset_nb;
	91	pwrseq->reset_nb.priority = 129;
	92	register_restart_handler(&pwrseq->reset_nb);
	93
	94	pwrseq->pwrseq.ops = &mmc_pwrseq_emmc_ops;
726b6324	95
0f12a0ce	96	return &pwrseq->pwrseq;
726b6324 MS	97	free:
726b6324 MS	98	kfree(pwrseq);
0f12a0ce	99	return ERR_PTR(ret);
726b6324	100	}