drivers/mmc/core/pwrseq_simple.c

   1 /*
   2  *  Copyright (C) 2014 Linaro Ltd
   3  *
   4  * Author: Ulf Hansson <ulf.hansson@linaro.org>
   5  *
   6  * License terms: GNU General Public License (GPL) version 2
   7  *
   8  *  Simple MMC power sequence management
   9  */
  10 #include <linux/clk.h>
  11 #include <linux/kernel.h>
  12 #include <linux/slab.h>
  13 #include <linux/device.h>
  14 #include <linux/err.h>
  15 #include <linux/gpio/consumer.h>
  16
  17 #include <linux/mmc/host.h>
  18
  19 #include "pwrseq.h"
  20
  21 struct mmc_pwrseq_simple {
  22         struct mmc_pwrseq pwrseq;
  23         bool clk_enabled;
  24         struct clk *ext_clk;
  25         struct gpio_descs *reset_gpios;
  26 };
  27
  28 #define to_pwrseq_simple(p) container_of(p, struct mmc_pwrseq_simple, pwrseq)
  29
  30 static void mmc_pwrseq_simple_set_gpios_value(struct mmc_pwrseq_simple *pwrseq,
  31                                               int value)
  32 {
  33         struct gpio_descs *reset_gpios = pwrseq->reset_gpios;
  34
  35         if (!IS_ERR(reset_gpios)) {
  36                 int i;
  37                 int values[reset_gpios->ndescs];
  38
  39                 for (i = 0; i < reset_gpios->ndescs; i++)
  40                         values[i] = value;
  41
  42                 gpiod_set_array_value_cansleep(
  43                         reset_gpios->ndescs, reset_gpios->desc, values);
  44         }
  45 }
  46
  47 static void mmc_pwrseq_simple_pre_power_on(struct mmc_host *host)
  48 {
  49         struct mmc_pwrseq_simple *pwrseq = to_pwrseq_simple(host->pwrseq);
  50
  51         if (!IS_ERR(pwrseq->ext_clk) && !pwrseq->clk_enabled) {
  52                 clk_prepare_enable(pwrseq->ext_clk);
  53                 pwrseq->clk_enabled = true;
  54         }
  55
  56         mmc_pwrseq_simple_set_gpios_value(pwrseq, 1);
  57 }
  58
  59 static void mmc_pwrseq_simple_post_power_on(struct mmc_host *host)
  60 {
  61         struct mmc_pwrseq_simple *pwrseq = to_pwrseq_simple(host->pwrseq);
  62
  63         mmc_pwrseq_simple_set_gpios_value(pwrseq, 0);
  64 }
  65
  66 static void mmc_pwrseq_simple_power_off(struct mmc_host *host)
  67 {
  68         struct mmc_pwrseq_simple *pwrseq = to_pwrseq_simple(host->pwrseq);
  69
  70         mmc_pwrseq_simple_set_gpios_value(pwrseq, 1);
  71
  72         if (!IS_ERR(pwrseq->ext_clk) && pwrseq->clk_enabled) {
  73                 clk_disable_unprepare(pwrseq->ext_clk);
  74                 pwrseq->clk_enabled = false;
  75         }
  76 }
  77
  78 static void mmc_pwrseq_simple_free(struct mmc_host *host)
  79 {
  80         struct mmc_pwrseq_simple *pwrseq = to_pwrseq_simple(host->pwrseq);
  81
  82         if (!IS_ERR(pwrseq->reset_gpios))
  83                 gpiod_put_array(pwrseq->reset_gpios);
  84
  85         if (!IS_ERR(pwrseq->ext_clk))
  86                 clk_put(pwrseq->ext_clk);
  87
  88         kfree(pwrseq);
  89 }
  90
  91 static const struct mmc_pwrseq_ops mmc_pwrseq_simple_ops = {
  92         .pre_power_on = mmc_pwrseq_simple_pre_power_on,
  93         .post_power_on = mmc_pwrseq_simple_post_power_on,
  94         .power_off = mmc_pwrseq_simple_power_off,
  95         .free = mmc_pwrseq_simple_free,
  96 };
  97
  98 struct mmc_pwrseq *mmc_pwrseq_simple_alloc(struct mmc_host *host,
  99                                            struct device *dev)
 100 {
 101         struct mmc_pwrseq_simple *pwrseq;
 102         int ret = 0;
 103
 104         pwrseq = kzalloc(sizeof(*pwrseq), GFP_KERNEL);
 105         if (!pwrseq)
 106                 return ERR_PTR(-ENOMEM);
 107
 108         pwrseq->ext_clk = clk_get(dev, "ext_clock");
 109         if (IS_ERR(pwrseq->ext_clk) &&
 110             PTR_ERR(pwrseq->ext_clk) != -ENOENT) {
 111                 ret = PTR_ERR(pwrseq->ext_clk);
 112                 goto free;
 113         }
 114
 115         pwrseq->reset_gpios = gpiod_get_array(dev, "reset", GPIOD_OUT_HIGH);
 116         if (IS_ERR(pwrseq->reset_gpios) &&
 117             PTR_ERR(pwrseq->reset_gpios) != -ENOENT &&
 118             PTR_ERR(pwrseq->reset_gpios) != -ENOSYS) {
 119                 ret = PTR_ERR(pwrseq->reset_gpios);
 120                 goto clk_put;
 121         }
 122
 123         pwrseq->pwrseq.ops = &mmc_pwrseq_simple_ops;
 124
 125         return &pwrseq->pwrseq;
 126 clk_put:
 127         if (!IS_ERR(pwrseq->ext_clk))
 128                 clk_put(pwrseq->ext_clk);
 129 free:
 130         kfree(pwrseq);
 131         return ERR_PTR(ret);
 132 }