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/kernel.h>
  11 #include <linux/slab.h>
  12 #include <linux/device.h>
  13 #include <linux/err.h>
  14 #include <linux/of_gpio.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         int nr_gpios;
  24         struct gpio_desc *reset_gpios[0];
  25 };
  26
  27 static void mmc_pwrseq_simple_set_gpios_value(struct mmc_pwrseq_simple *pwrseq,
  28                                               int value)
  29 {
  30         int i;
  31
  32         for (i = 0; i < pwrseq->nr_gpios; i++)
  33                 if (!IS_ERR(pwrseq->reset_gpios[i]))
  34                         gpiod_set_value_cansleep(pwrseq->reset_gpios[i], value);
  35 }
  36
  37 static void mmc_pwrseq_simple_pre_power_on(struct mmc_host *host)
  38 {
  39         struct mmc_pwrseq_simple *pwrseq = container_of(host->pwrseq,
  40                                         struct mmc_pwrseq_simple, pwrseq);
  41
  42         mmc_pwrseq_simple_set_gpios_value(pwrseq, 1);
  43 }
  44
  45 static void mmc_pwrseq_simple_post_power_on(struct mmc_host *host)
  46 {
  47         struct mmc_pwrseq_simple *pwrseq = container_of(host->pwrseq,
  48                                         struct mmc_pwrseq_simple, pwrseq);
  49
  50         mmc_pwrseq_simple_set_gpios_value(pwrseq, 0);
  51 }
  52
  53 static void mmc_pwrseq_simple_free(struct mmc_host *host)
  54 {
  55         struct mmc_pwrseq_simple *pwrseq = container_of(host->pwrseq,
  56                                         struct mmc_pwrseq_simple, pwrseq);
  57         int i;
  58
  59         for (i = 0; i < pwrseq->nr_gpios; i++)
  60                 if (!IS_ERR(pwrseq->reset_gpios[i]))
  61                         gpiod_put(pwrseq->reset_gpios[i]);
  62
  63         kfree(pwrseq);
  64         host->pwrseq = NULL;
  65 }
  66
  67 static struct mmc_pwrseq_ops mmc_pwrseq_simple_ops = {
  68         .pre_power_on = mmc_pwrseq_simple_pre_power_on,
  69         .post_power_on = mmc_pwrseq_simple_post_power_on,
  70         .power_off = mmc_pwrseq_simple_pre_power_on,
  71         .free = mmc_pwrseq_simple_free,
  72 };
  73
  74 int mmc_pwrseq_simple_alloc(struct mmc_host *host, struct device *dev)
  75 {
  76         struct mmc_pwrseq_simple *pwrseq;
  77         int i, nr_gpios, ret = 0;
  78
  79         nr_gpios = of_gpio_named_count(dev->of_node, "reset-gpios");
  80         if (nr_gpios < 0)
  81                 nr_gpios = 0;
  82
  83         pwrseq = kzalloc(sizeof(struct mmc_pwrseq_simple) + nr_gpios *
  84                          sizeof(struct gpio_desc *), GFP_KERNEL);
  85         if (!pwrseq)
  86                 return -ENOMEM;
  87
  88         for (i = 0; i < nr_gpios; i++) {
  89                 pwrseq->reset_gpios[i] = gpiod_get_index(dev, "reset", i,
  90                                                          GPIOD_OUT_HIGH);
  91                 if (IS_ERR(pwrseq->reset_gpios[i]) &&
  92                     PTR_ERR(pwrseq->reset_gpios[i]) != -ENOENT &&
  93                     PTR_ERR(pwrseq->reset_gpios[i]) != -ENOSYS) {
  94                         ret = PTR_ERR(pwrseq->reset_gpios[i]);
  95
  96                         while (--i)
  97                                 gpiod_put(pwrseq->reset_gpios[i]);
  98
  99                         goto free;
 100                 }
 101         }
 102
 103         pwrseq->nr_gpios = nr_gpios;
 104         pwrseq->pwrseq.ops = &mmc_pwrseq_simple_ops;
 105         host->pwrseq = &pwrseq->pwrseq;
 106
 107         return 0;
 108 free:
 109         kfree(pwrseq);
 110         return ret;
 111 }