linux/drivers/mmc/core/pwrseq_emmc.c
Alexandre Courbot 0f12a0ce4c mmc: pwrseq: simplify alloc/free hooks
The alloc() and free() hooks required each pwrseq implementation to set
host->pwrseq themselves. This is error-prone and could be done at a
higher level if alloc() was changed to return a pointer to a struct
mmc_pwrseq instead of an error code.

This patch performs this change and moves the burden of maintaining
host->pwrseq from the power sequence hooks to the pwrseq code.

Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
2015-03-23 14:13:42 +01:00

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_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);
}