drivers/mmc/core/pwrseq_simple.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *  Copyright (C) 2014 Linaro Ltd
   4  *
   5  * Author: Ulf Hansson <ulf.hansson@linaro.org>
   6  *
   7  *  Simple MMC power sequence management
   8  */
   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
  25 struct 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
  36 static 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                 else
  52                         bitmap_zero(values, nvalues);
  53
  54                 gpiod_set_array_value_cansleep(nvalues, reset_gpios->desc,
  55                                                reset_gpios->info, values);
  56
  57                 kfree(values);
  58         }
  59 }
  60
  61 static 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
  73 static 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
  83 static 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
  99 static 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
 105 static const struct of_device_id mmc_pwrseq_simple_of_match[] = {
 106         { .compatible = "mmc-pwrseq-simple",},
 107         {/* sentinel */},
 108 };
 109 MODULE_DEVICE_TABLE(of, mmc_pwrseq_simple_of_match);
 110
 111 static 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 PTR_ERR(pwrseq->ext_clk);
 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 PTR_ERR(pwrseq->reset_gpios);
 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
 145 static int 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         return 0;
 152 }
 153
 154 static struct platform_driver mmc_pwrseq_simple_driver = {
 155         .probe = mmc_pwrseq_simple_probe,
 156         .remove = mmc_pwrseq_simple_remove,
 157         .driver = {
 158                 .name = "pwrseq_simple",
 159                 .of_match_table = mmc_pwrseq_simple_of_match,
 160         },
 161 };
 162
 163 module_platform_driver(mmc_pwrseq_simple_driver);
 164 MODULE_LICENSE("GPL v2");