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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;
int nr_gpios;
struct gpio_desc *reset_gpios[0];
};
static void mmc_pwrseq_simple_set_gpios_value(struct mmc_pwrseq_simple *pwrseq,
int value)
{
int i;
for (i = 0; i < pwrseq->nr_gpios; i++)
if (!IS_ERR(pwrseq->reset_gpios[i]))
gpiod_set_value_cansleep(pwrseq->reset_gpios[i], value);
}
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);
int i;
for (i = 0; i < pwrseq->nr_gpios; i++)
if (!IS_ERR(pwrseq->reset_gpios[i]))
gpiod_put(pwrseq->reset_gpios[i]);
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 i, nr_gpios, ret = 0;
nr_gpios = of_gpio_named_count(dev->of_node, "reset-gpios");
if (nr_gpios < 0)
nr_gpios = 0;
pwrseq = kzalloc(sizeof(struct mmc_pwrseq_simple) + nr_gpios *
sizeof(struct gpio_desc *), 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;
}
for (i = 0; i < nr_gpios; i++) {
pwrseq->reset_gpios[i] = gpiod_get_index(dev, "reset", i,
GPIOD_OUT_HIGH);
if (IS_ERR(pwrseq->reset_gpios[i]) &&
PTR_ERR(pwrseq->reset_gpios[i]) != -ENOENT &&
PTR_ERR(pwrseq->reset_gpios[i]) != -ENOSYS) {
ret = PTR_ERR(pwrseq->reset_gpios[i]);
while (i--)
gpiod_put(pwrseq->reset_gpios[i]);
goto clk_put;
}
}
pwrseq->nr_gpios = nr_gpios;
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);
}
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