mirror of https://gitee.com/openkylin/linux.git
101 lines
2.4 KiB
C
101 lines
2.4 KiB
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(dev, "reset", 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 255 is the highest priority
|
|
* so it will be executed before any system reboot handler.
|
|
*/
|
|
pwrseq->reset_nb.notifier_call = mmc_pwrseq_emmc_reset_nb;
|
|
pwrseq->reset_nb.priority = 255;
|
|
register_restart_handler(&pwrseq->reset_nb);
|
|
|
|
pwrseq->pwrseq.ops = &mmc_pwrseq_emmc_ops;
|
|
|
|
return &pwrseq->pwrseq;
|
|
free:
|
|
kfree(pwrseq);
|
|
return ERR_PTR(ret);
|
|
}
|