165 строки
4.1 KiB
C
165 строки
4.1 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (C) 2014 Linaro Ltd
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*
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* Author: Ulf Hansson <ulf.hansson@linaro.org>
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*
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* Simple MMC power sequence management
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*/
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#include <linux/clk.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/platform_device.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/device.h>
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#include <linux/err.h>
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#include <linux/gpio/consumer.h>
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#include <linux/delay.h>
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#include <linux/property.h>
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#include <linux/mmc/host.h>
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#include "pwrseq.h"
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struct mmc_pwrseq_simple {
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struct mmc_pwrseq pwrseq;
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bool clk_enabled;
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u32 post_power_on_delay_ms;
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u32 power_off_delay_us;
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struct clk *ext_clk;
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struct gpio_descs *reset_gpios;
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};
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#define to_pwrseq_simple(p) container_of(p, struct mmc_pwrseq_simple, pwrseq)
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static void mmc_pwrseq_simple_set_gpios_value(struct mmc_pwrseq_simple *pwrseq,
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int value)
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{
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struct gpio_descs *reset_gpios = pwrseq->reset_gpios;
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if (!IS_ERR(reset_gpios)) {
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unsigned long *values;
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int nvalues = reset_gpios->ndescs;
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values = bitmap_alloc(nvalues, GFP_KERNEL);
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if (!values)
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return;
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if (value)
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bitmap_fill(values, nvalues);
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else
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bitmap_zero(values, nvalues);
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gpiod_set_array_value_cansleep(nvalues, reset_gpios->desc,
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reset_gpios->info, values);
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kfree(values);
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}
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}
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static void mmc_pwrseq_simple_pre_power_on(struct mmc_host *host)
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{
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struct mmc_pwrseq_simple *pwrseq = to_pwrseq_simple(host->pwrseq);
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if (!IS_ERR(pwrseq->ext_clk) && !pwrseq->clk_enabled) {
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clk_prepare_enable(pwrseq->ext_clk);
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pwrseq->clk_enabled = true;
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}
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mmc_pwrseq_simple_set_gpios_value(pwrseq, 1);
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}
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static void mmc_pwrseq_simple_post_power_on(struct mmc_host *host)
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{
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struct mmc_pwrseq_simple *pwrseq = to_pwrseq_simple(host->pwrseq);
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mmc_pwrseq_simple_set_gpios_value(pwrseq, 0);
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if (pwrseq->post_power_on_delay_ms)
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msleep(pwrseq->post_power_on_delay_ms);
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}
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static void mmc_pwrseq_simple_power_off(struct mmc_host *host)
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{
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struct mmc_pwrseq_simple *pwrseq = to_pwrseq_simple(host->pwrseq);
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mmc_pwrseq_simple_set_gpios_value(pwrseq, 1);
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if (pwrseq->power_off_delay_us)
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usleep_range(pwrseq->power_off_delay_us,
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2 * pwrseq->power_off_delay_us);
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if (!IS_ERR(pwrseq->ext_clk) && pwrseq->clk_enabled) {
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clk_disable_unprepare(pwrseq->ext_clk);
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pwrseq->clk_enabled = false;
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}
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}
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static const struct mmc_pwrseq_ops mmc_pwrseq_simple_ops = {
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.pre_power_on = mmc_pwrseq_simple_pre_power_on,
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.post_power_on = mmc_pwrseq_simple_post_power_on,
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.power_off = mmc_pwrseq_simple_power_off,
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};
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static const struct of_device_id mmc_pwrseq_simple_of_match[] = {
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{ .compatible = "mmc-pwrseq-simple",},
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{/* sentinel */},
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};
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MODULE_DEVICE_TABLE(of, mmc_pwrseq_simple_of_match);
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static int mmc_pwrseq_simple_probe(struct platform_device *pdev)
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{
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struct mmc_pwrseq_simple *pwrseq;
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struct device *dev = &pdev->dev;
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pwrseq = devm_kzalloc(dev, sizeof(*pwrseq), GFP_KERNEL);
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if (!pwrseq)
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return -ENOMEM;
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pwrseq->ext_clk = devm_clk_get(dev, "ext_clock");
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if (IS_ERR(pwrseq->ext_clk) && PTR_ERR(pwrseq->ext_clk) != -ENOENT)
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return PTR_ERR(pwrseq->ext_clk);
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pwrseq->reset_gpios = devm_gpiod_get_array(dev, "reset",
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GPIOD_OUT_HIGH);
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if (IS_ERR(pwrseq->reset_gpios) &&
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PTR_ERR(pwrseq->reset_gpios) != -ENOENT &&
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PTR_ERR(pwrseq->reset_gpios) != -ENOSYS) {
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return PTR_ERR(pwrseq->reset_gpios);
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}
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device_property_read_u32(dev, "post-power-on-delay-ms",
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&pwrseq->post_power_on_delay_ms);
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device_property_read_u32(dev, "power-off-delay-us",
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&pwrseq->power_off_delay_us);
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pwrseq->pwrseq.dev = dev;
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pwrseq->pwrseq.ops = &mmc_pwrseq_simple_ops;
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pwrseq->pwrseq.owner = THIS_MODULE;
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platform_set_drvdata(pdev, pwrseq);
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return mmc_pwrseq_register(&pwrseq->pwrseq);
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}
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static int mmc_pwrseq_simple_remove(struct platform_device *pdev)
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{
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struct mmc_pwrseq_simple *pwrseq = platform_get_drvdata(pdev);
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mmc_pwrseq_unregister(&pwrseq->pwrseq);
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return 0;
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}
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static struct platform_driver mmc_pwrseq_simple_driver = {
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.probe = mmc_pwrseq_simple_probe,
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.remove = mmc_pwrseq_simple_remove,
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.driver = {
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.name = "pwrseq_simple",
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.of_match_table = mmc_pwrseq_simple_of_match,
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},
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};
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module_platform_driver(mmc_pwrseq_simple_driver);
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MODULE_LICENSE("GPL v2");
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