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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/platform_device.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];
};
#define to_pwrseq_simple(p) container_of(p, struct mmc_pwrseq_simple, pwrseq)
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 = to_pwrseq_simple(host->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 = to_pwrseq_simple(host->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 = to_pwrseq_simple(host->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 = to_pwrseq_simple(host->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);
}
int mmc_pwrseq_simple_alloc(struct mmc_host *host)
{
struct mmc_pwrseq_simple *pwrseq = to_pwrseq_simple(host->pwrseq);
struct device *dev = host->pwrseq->dev;
int i, ret = 0;
pwrseq->ext_clk = clk_get(dev, "ext_clock");
if (IS_ERR(pwrseq->ext_clk) &&
PTR_ERR(pwrseq->ext_clk) != -ENOENT) {
return PTR_ERR(pwrseq->ext_clk);
}
for (i = 0; i < pwrseq->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]);
if (!IS_ERR(pwrseq->ext_clk))
clk_put(pwrseq->ext_clk);
return -EINVAL;
}
}
return 0;
}
static struct mmc_pwrseq_ops mmc_pwrseq_simple_ops = {
.alloc = mmc_pwrseq_simple_alloc,
.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,
};
static const struct of_device_id mmc_pwrseq_simple_of_match[] = {
{ .compatible = "mmc-pwrseq-simple",},
{/* sentinel */},
};
MODULE_DEVICE_TABLE(of, mmc_pwrseq_simple_of_match);
static int mmc_pwrseq_simple_probe(struct platform_device *pdev)
{
struct mmc_pwrseq_simple *spwrseq;
struct device *dev = &pdev->dev;
int nr_gpios;
nr_gpios = of_gpio_named_count(dev->of_node, "reset-gpios");
if (nr_gpios < 0)
nr_gpios = 0;
spwrseq = devm_kzalloc(dev, sizeof(struct mmc_pwrseq_simple) + nr_gpios *
sizeof(struct gpio_desc *), GFP_KERNEL);
if (!spwrseq)
return -ENOMEM;
spwrseq->pwrseq.dev = dev;
spwrseq->nr_gpios = nr_gpios;
spwrseq->pwrseq.ops = &mmc_pwrseq_simple_ops;
platform_set_drvdata(pdev, spwrseq);
return mmc_pwrseq_register(&spwrseq->pwrseq);
}
static int mmc_pwrseq_simple_remove(struct platform_device *pdev)
{
struct mmc_pwrseq_simple *spwrseq = platform_get_drvdata(pdev);
return mmc_pwrseq_unregister(&spwrseq->pwrseq);
}
static struct platform_driver mmc_pwrseq_simple_driver = {
.probe = mmc_pwrseq_simple_probe,
.remove = mmc_pwrseq_simple_remove,
.driver = {
.name = "pwrseq_simple",
.of_match_table = mmc_pwrseq_simple_of_match,
},
};
module_platform_driver(mmc_pwrseq_simple_driver);
MODULE_LICENSE("GPL v2");
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