drivers/mmc/host/of_mmc_spi.c

   1 /*
   2  * OpenFirmware bindings for the MMC-over-SPI driver
   3  *
   4  * Copyright (c) MontaVista Software, Inc. 2008.
   5  *
   6  * Author: Anton Vorontsov <avorontsov@ru.mvista.com>
   7  *
   8  * This program is free software; you can redistribute  it and/or modify it
   9  * under  the terms of  the GNU General  Public License as published by the
  10  * Free Software Foundation;  either version 2 of the  License, or (at your
  11  * option) any later version.
  12  */
  13
  14 #include <linux/kernel.h>
  15 #include <linux/module.h>
  16 #include <linux/device.h>
  17 #include <linux/slab.h>
  18 #include <linux/gpio.h>
  19 #include <linux/of.h>
  20 #include <linux/of_gpio.h>
  21 #include <linux/spi/spi.h>
  22 #include <linux/spi/mmc_spi.h>
  23 #include <linux/mmc/core.h>
  24 #include <linux/mmc/host.h>
  25
  26 MODULE_LICENSE("GPL");
  27
  28 enum {
  29         CD_GPIO = 0,
  30         WP_GPIO,
  31         NUM_GPIOS,
  32 };
  33
  34 struct of_mmc_spi {
  35         int gpios[NUM_GPIOS];
  36         bool alow_gpios[NUM_GPIOS];
  37         struct mmc_spi_platform_data pdata;
  38 };
  39
  40 static struct of_mmc_spi *to_of_mmc_spi(struct device *dev)
  41 {
  42         return container_of(dev->platform_data, struct of_mmc_spi, pdata);
  43 }
  44
  45 static int of_mmc_spi_read_gpio(struct device *dev, int gpio_num)
  46 {
  47         struct of_mmc_spi *oms = to_of_mmc_spi(dev);
  48         bool active_low = oms->alow_gpios[gpio_num];
  49         bool value = gpio_get_value(oms->gpios[gpio_num]);
  50
  51         return active_low ^ value;
  52 }
  53
  54 static int of_mmc_spi_get_cd(struct device *dev)
  55 {
  56         return of_mmc_spi_read_gpio(dev, CD_GPIO);
  57 }
  58
  59 static int of_mmc_spi_get_ro(struct device *dev)
  60 {
  61         return of_mmc_spi_read_gpio(dev, WP_GPIO);
  62 }
  63
  64 struct mmc_spi_platform_data *mmc_spi_get_pdata(struct spi_device *spi)
  65 {
  66         struct device *dev = &spi->dev;
  67         struct device_node *np = dev->of_node;
  68         struct of_mmc_spi *oms;
  69         const u32 *voltage_ranges;
  70         int num_ranges;
  71         int i;
  72         int ret = -EINVAL;
  73
  74         if (dev->platform_data || !np)
  75                 return dev->platform_data;
  76
  77         oms = kzalloc(sizeof(*oms), GFP_KERNEL);
  78         if (!oms)
  79                 return NULL;
  80
  81         voltage_ranges = of_get_property(np, "voltage-ranges", &num_ranges);
  82         num_ranges = num_ranges / sizeof(*voltage_ranges) / 2;
  83         if (!voltage_ranges || !num_ranges) {
  84                 dev_err(dev, "OF: voltage-ranges unspecified\n");
  85                 goto err_ocr;
  86         }
  87
  88         for (i = 0; i < num_ranges; i++) {
  89                 const int j = i * 2;
  90                 u32 mask;
  91
  92                 mask = mmc_vddrange_to_ocrmask(voltage_ranges[j],
  93                                                voltage_ranges[j + 1]);
  94                 if (!mask) {
  95                         ret = -EINVAL;
  96                         dev_err(dev, "OF: voltage-range #%d is invalid\n", i);
  97                         goto err_ocr;
  98                 }
  99                 oms->pdata.ocr_mask |= mask;
 100         }
 101
 102         for (i = 0; i < ARRAY_SIZE(oms->gpios); i++) {
 103                 enum of_gpio_flags gpio_flags;
 104
 105                 oms->gpios[i] = of_get_gpio_flags(np, i, &gpio_flags);
 106                 if (!gpio_is_valid(oms->gpios[i]))
 107                         continue;
 108
 109                 ret = gpio_request(oms->gpios[i], dev_name(dev));
 110                 if (ret < 0) {
 111                         oms->gpios[i] = -EINVAL;
 112                         continue;
 113                 }
 114
 115                 if (gpio_flags & OF_GPIO_ACTIVE_LOW)
 116                         oms->alow_gpios[i] = true;
 117         }
 118
 119         if (gpio_is_valid(oms->gpios[CD_GPIO]))
 120                 oms->pdata.get_cd = of_mmc_spi_get_cd;
 121         if (gpio_is_valid(oms->gpios[WP_GPIO]))
 122                 oms->pdata.get_ro = of_mmc_spi_get_ro;
 123
 124         /* We don't support interrupts yet, let's poll. */
 125         oms->pdata.caps |= MMC_CAP_NEEDS_POLL;
 126
 127         dev->platform_data = &oms->pdata;
 128         return dev->platform_data;
 129 err_ocr:
 130         kfree(oms);
 131         return NULL;
 132 }
 133 EXPORT_SYMBOL(mmc_spi_get_pdata);
 134
 135 void mmc_spi_put_pdata(struct spi_device *spi)
 136 {
 137         struct device *dev = &spi->dev;
 138         struct device_node *np = dev->of_node;
 139         struct of_mmc_spi *oms = to_of_mmc_spi(dev);
 140         int i;
 141
 142         if (!dev->platform_data || !np)
 143                 return;
 144
 145         for (i = 0; i < ARRAY_SIZE(oms->gpios); i++) {
 146                 if (gpio_is_valid(oms->gpios[i]))
 147                         gpio_free(oms->gpios[i]);
 148         }
 149         kfree(oms);
 150         dev->platform_data = NULL;
 151 }
 152 EXPORT_SYMBOL(mmc_spi_put_pdata);