pwrseq_simple.c
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/*
* Copyright (C) 2014 Linaro Ltd
*
* Author: Ulf Hansson <ulf.hansson@linaro.org>
*
* License terms: GNU General Public License (GPL) version 2
*
* Simple MMC power sequence management
*/
#include <linux/clk.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/of_gpio.h>
#include <linux/gpio/consumer.h>
#include <linux/mmc/host.h>
#include "pwrseq.h"
struct mmc_pwrseq_simple {
struct mmc_pwrseq pwrseq;
bool clk_enabled;
struct clk *ext_clk;
struct gpio_descs *reset_gpios;
};
static void mmc_pwrseq_simple_set_gpios_value(struct mmc_pwrseq_simple *pwrseq,
int value)
{
int i;
struct gpio_descs *reset_gpios = pwrseq->reset_gpios;
int values[reset_gpios->ndescs];
for (i = 0; i < reset_gpios->ndescs; i++)
values[i] = value;
gpiod_set_array_value_cansleep(reset_gpios->ndescs, reset_gpios->desc,
values);
}
static void mmc_pwrseq_simple_pre_power_on(struct mmc_host *host)
{
struct mmc_pwrseq_simple *pwrseq = container_of(host->pwrseq,
struct mmc_pwrseq_simple, pwrseq);
if (!IS_ERR(pwrseq->ext_clk) && !pwrseq->clk_enabled) {
clk_prepare_enable(pwrseq->ext_clk);
pwrseq->clk_enabled = true;
}
mmc_pwrseq_simple_set_gpios_value(pwrseq, 1);
}
static void mmc_pwrseq_simple_post_power_on(struct mmc_host *host)
{
struct mmc_pwrseq_simple *pwrseq = container_of(host->pwrseq,
struct mmc_pwrseq_simple, pwrseq);
mmc_pwrseq_simple_set_gpios_value(pwrseq, 0);
}
static void mmc_pwrseq_simple_power_off(struct mmc_host *host)
{
struct mmc_pwrseq_simple *pwrseq = container_of(host->pwrseq,
struct mmc_pwrseq_simple, pwrseq);
mmc_pwrseq_simple_set_gpios_value(pwrseq, 1);
if (!IS_ERR(pwrseq->ext_clk) && pwrseq->clk_enabled) {
clk_disable_unprepare(pwrseq->ext_clk);
pwrseq->clk_enabled = false;
}
}
static void mmc_pwrseq_simple_free(struct mmc_host *host)
{
struct mmc_pwrseq_simple *pwrseq = container_of(host->pwrseq,
struct mmc_pwrseq_simple, pwrseq);
gpiod_put_array(pwrseq->reset_gpios);
if (!IS_ERR(pwrseq->ext_clk))
clk_put(pwrseq->ext_clk);
kfree(pwrseq);
}
static struct mmc_pwrseq_ops mmc_pwrseq_simple_ops = {
.pre_power_on = mmc_pwrseq_simple_pre_power_on,
.post_power_on = mmc_pwrseq_simple_post_power_on,
.power_off = mmc_pwrseq_simple_power_off,
.free = mmc_pwrseq_simple_free,
};
struct mmc_pwrseq *mmc_pwrseq_simple_alloc(struct mmc_host *host,
struct device *dev)
{
struct mmc_pwrseq_simple *pwrseq;
int ret = 0;
pwrseq = kzalloc(sizeof(*pwrseq), GFP_KERNEL);
if (!pwrseq)
return ERR_PTR(-ENOMEM);
pwrseq->ext_clk = clk_get(dev, "ext_clock");
if (IS_ERR(pwrseq->ext_clk) &&
PTR_ERR(pwrseq->ext_clk) != -ENOENT) {
ret = PTR_ERR(pwrseq->ext_clk);
goto free;
}
pwrseq->reset_gpios = gpiod_get_array(dev, "reset", GPIOD_OUT_HIGH);
if (IS_ERR(pwrseq->reset_gpios)) {
ret = PTR_ERR(pwrseq->reset_gpios);
goto clk_put;
}
pwrseq->pwrseq.ops = &mmc_pwrseq_simple_ops;
return &pwrseq->pwrseq;
clk_put:
if (!IS_ERR(pwrseq->ext_clk))
clk_put(pwrseq->ext_clk);
free:
kfree(pwrseq);
return ERR_PTR(ret);
}