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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Copyright (C) 2014 Linaro Ltd4 *5 * Author: Ulf Hansson <ulf.hansson@linaro.org>6 *7 * Simple MMC power sequence management8 */9#include <linux/clk.h>10#include <linux/init.h>11#include <linux/kernel.h>12#include <linux/platform_device.h>13#include <linux/module.h>14#include <linux/slab.h>15#include <linux/device.h>16#include <linux/err.h>17#include <linux/gpio/consumer.h>18#include <linux/delay.h>19#include <linux/property.h>20 21#include <linux/mmc/host.h>22 23#include "pwrseq.h"24 25struct mmc_pwrseq_simple {26 struct mmc_pwrseq pwrseq;27 bool clk_enabled;28 u32 post_power_on_delay_ms;29 u32 power_off_delay_us;30 struct clk *ext_clk;31 struct gpio_descs *reset_gpios;32};33 34#define to_pwrseq_simple(p) container_of(p, struct mmc_pwrseq_simple, pwrseq)35 36static void mmc_pwrseq_simple_set_gpios_value(struct mmc_pwrseq_simple *pwrseq,37 int value)38{39 struct gpio_descs *reset_gpios = pwrseq->reset_gpios;40 41 if (!IS_ERR(reset_gpios)) {42 unsigned long *values;43 int nvalues = reset_gpios->ndescs;44 45 values = bitmap_alloc(nvalues, GFP_KERNEL);46 if (!values)47 return;48 49 if (value)50 bitmap_fill(values, nvalues);51 else52 bitmap_zero(values, nvalues);53 54 gpiod_set_array_value_cansleep(nvalues, reset_gpios->desc,55 reset_gpios->info, values);56 57 bitmap_free(values);58 }59}60 61static void mmc_pwrseq_simple_pre_power_on(struct mmc_host *host)62{63 struct mmc_pwrseq_simple *pwrseq = to_pwrseq_simple(host->pwrseq);64 65 if (!IS_ERR(pwrseq->ext_clk) && !pwrseq->clk_enabled) {66 clk_prepare_enable(pwrseq->ext_clk);67 pwrseq->clk_enabled = true;68 }69 70 mmc_pwrseq_simple_set_gpios_value(pwrseq, 1);71}72 73static void mmc_pwrseq_simple_post_power_on(struct mmc_host *host)74{75 struct mmc_pwrseq_simple *pwrseq = to_pwrseq_simple(host->pwrseq);76 77 mmc_pwrseq_simple_set_gpios_value(pwrseq, 0);78 79 if (pwrseq->post_power_on_delay_ms)80 msleep(pwrseq->post_power_on_delay_ms);81}82 83static void mmc_pwrseq_simple_power_off(struct mmc_host *host)84{85 struct mmc_pwrseq_simple *pwrseq = to_pwrseq_simple(host->pwrseq);86 87 mmc_pwrseq_simple_set_gpios_value(pwrseq, 1);88 89 if (pwrseq->power_off_delay_us)90 usleep_range(pwrseq->power_off_delay_us,91 2 * pwrseq->power_off_delay_us);92 93 if (!IS_ERR(pwrseq->ext_clk) && pwrseq->clk_enabled) {94 clk_disable_unprepare(pwrseq->ext_clk);95 pwrseq->clk_enabled = false;96 }97}98 99static const struct mmc_pwrseq_ops mmc_pwrseq_simple_ops = {100 .pre_power_on = mmc_pwrseq_simple_pre_power_on,101 .post_power_on = mmc_pwrseq_simple_post_power_on,102 .power_off = mmc_pwrseq_simple_power_off,103};104 105static const struct of_device_id mmc_pwrseq_simple_of_match[] = {106 { .compatible = "mmc-pwrseq-simple",},107 {/* sentinel */},108};109MODULE_DEVICE_TABLE(of, mmc_pwrseq_simple_of_match);110 111static int mmc_pwrseq_simple_probe(struct platform_device *pdev)112{113 struct mmc_pwrseq_simple *pwrseq;114 struct device *dev = &pdev->dev;115 116 pwrseq = devm_kzalloc(dev, sizeof(*pwrseq), GFP_KERNEL);117 if (!pwrseq)118 return -ENOMEM;119 120 pwrseq->ext_clk = devm_clk_get(dev, "ext_clock");121 if (IS_ERR(pwrseq->ext_clk) && PTR_ERR(pwrseq->ext_clk) != -ENOENT)122 return dev_err_probe(dev, PTR_ERR(pwrseq->ext_clk), "external clock not ready\n");123 124 pwrseq->reset_gpios = devm_gpiod_get_array(dev, "reset",125 GPIOD_OUT_HIGH);126 if (IS_ERR(pwrseq->reset_gpios) &&127 PTR_ERR(pwrseq->reset_gpios) != -ENOENT &&128 PTR_ERR(pwrseq->reset_gpios) != -ENOSYS) {129 return dev_err_probe(dev, PTR_ERR(pwrseq->reset_gpios), "reset GPIOs not ready\n");130 }131 132 device_property_read_u32(dev, "post-power-on-delay-ms",133 &pwrseq->post_power_on_delay_ms);134 device_property_read_u32(dev, "power-off-delay-us",135 &pwrseq->power_off_delay_us);136 137 pwrseq->pwrseq.dev = dev;138 pwrseq->pwrseq.ops = &mmc_pwrseq_simple_ops;139 pwrseq->pwrseq.owner = THIS_MODULE;140 platform_set_drvdata(pdev, pwrseq);141 142 return mmc_pwrseq_register(&pwrseq->pwrseq);143}144 145static void mmc_pwrseq_simple_remove(struct platform_device *pdev)146{147 struct mmc_pwrseq_simple *pwrseq = platform_get_drvdata(pdev);148 149 mmc_pwrseq_unregister(&pwrseq->pwrseq);150}151 152static struct platform_driver mmc_pwrseq_simple_driver = {153 .probe = mmc_pwrseq_simple_probe,154 .remove_new = mmc_pwrseq_simple_remove,155 .driver = {156 .name = "pwrseq_simple",157 .of_match_table = mmc_pwrseq_simple_of_match,158 },159};160 161module_platform_driver(mmc_pwrseq_simple_driver);162MODULE_DESCRIPTION("Simple power sequence management for MMC");163MODULE_LICENSE("GPL v2");164