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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2014 Linaro Ltd
*
* Author: Ulf Hansson <ulf.hansson@linaro.org>
*
* Simple MMC power sequence management
*/
#include <linux/clk.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/platform_device.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/gpio/consumer.h>
#include <linux/delay.h>
#include <linux/property.h>
#include <linux/of.h>
#include <linux/reset.h>
#include <linux/mmc/host.h>
#include "pwrseq.h"
struct mmc_pwrseq_simple {
struct mmc_pwrseq pwrseq;
bool clk_enabled;
u32 post_power_on_delay_ms;
u32 power_off_delay_us;
struct clk *ext_clk;
struct gpio_descs *reset_gpios;
struct reset_control *reset_ctrl;
};
#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)
{
struct gpio_descs *reset_gpios = pwrseq->reset_gpios;
if (!IS_ERR(reset_gpios)) {
unsigned long *values;
int nvalues = reset_gpios->ndescs;
values = bitmap_alloc(nvalues, GFP_KERNEL);
if (!values)
return;
if (value)
bitmap_fill(values, nvalues);
else
bitmap_zero(values, nvalues);
gpiod_set_array_value_cansleep(nvalues, reset_gpios->desc,
reset_gpios->info, values);
bitmap_free(values);
}
}
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;
}
if (pwrseq->reset_ctrl) {
reset_control_deassert(pwrseq->reset_ctrl);
reset_control_assert(pwrseq->reset_ctrl);
} else
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);
if (pwrseq->reset_ctrl)
reset_control_deassert(pwrseq->reset_ctrl);
else
mmc_pwrseq_simple_set_gpios_value(pwrseq, 0);
if (pwrseq->post_power_on_delay_ms)
msleep(pwrseq->post_power_on_delay_ms);
}
static void mmc_pwrseq_simple_power_off(struct mmc_host *host)
{
struct mmc_pwrseq_simple *pwrseq = to_pwrseq_simple(host->pwrseq);
if (pwrseq->reset_ctrl)
reset_control_assert(pwrseq->reset_ctrl);
else
mmc_pwrseq_simple_set_gpios_value(pwrseq, 1);
if (pwrseq->power_off_delay_us)
usleep_range(pwrseq->power_off_delay_us,
2 * pwrseq->power_off_delay_us);
if (!IS_ERR(pwrseq->ext_clk) && pwrseq->clk_enabled) {
clk_disable_unprepare(pwrseq->ext_clk);
pwrseq->clk_enabled = false;
}
}
static const 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,
};
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 *pwrseq;
struct device *dev = &pdev->dev;
int ngpio;
pwrseq = devm_kzalloc(dev, sizeof(*pwrseq), GFP_KERNEL);
if (!pwrseq)
return -ENOMEM;
pwrseq->ext_clk = devm_clk_get(dev, "ext_clock");
if (IS_ERR(pwrseq->ext_clk) && PTR_ERR(pwrseq->ext_clk) != -ENOENT)
return dev_err_probe(dev, PTR_ERR(pwrseq->ext_clk), "external clock not ready\n");
ngpio = of_count_phandle_with_args(dev->of_node, "reset-gpios", "#gpio-cells");
if (ngpio == 1) {
pwrseq->reset_ctrl = devm_reset_control_get_optional_shared(dev, NULL);
if (IS_ERR(pwrseq->reset_ctrl))
return dev_err_probe(dev, PTR_ERR(pwrseq->reset_ctrl),
"reset control not ready\n");
}
/*
* Fallback to GPIO based reset control in case of multiple reset lines
* are specified or the platform doesn't have support for RESET at all.
*/
if (!pwrseq->reset_ctrl) {
pwrseq->reset_gpios = devm_gpiod_get_array(dev, "reset", GPIOD_OUT_HIGH);
if (IS_ERR(pwrseq->reset_gpios) &&
PTR_ERR(pwrseq->reset_gpios) != -ENOENT &&
PTR_ERR(pwrseq->reset_gpios) != -ENOSYS) {
return dev_err_probe(dev, PTR_ERR(pwrseq->reset_gpios),
"reset GPIOs not ready\n");
}
}
device_property_read_u32(dev, "post-power-on-delay-ms",
&pwrseq->post_power_on_delay_ms);
device_property_read_u32(dev, "power-off-delay-us",
&pwrseq->power_off_delay_us);
pwrseq->pwrseq.dev = dev;
pwrseq->pwrseq.ops = &mmc_pwrseq_simple_ops;
pwrseq->pwrseq.owner = THIS_MODULE;
platform_set_drvdata(pdev, pwrseq);
return mmc_pwrseq_register(&pwrseq->pwrseq);
}
static void mmc_pwrseq_simple_remove(struct platform_device *pdev)
{
struct mmc_pwrseq_simple *pwrseq = platform_get_drvdata(pdev);
mmc_pwrseq_unregister(&pwrseq->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_DESCRIPTION("Simple power sequence management for MMC");
MODULE_LICENSE("GPL v2");
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