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/gpio.h>
  18 #include <linux/of.h>
  19 #include <linux/of_gpio.h>
  20 #include <linux/spi/spi.h>
  21 #include <linux/spi/mmc_spi.h>
  22 #include <linux/mmc/core.h>
  23 #include <linux/mmc/host.h>
  24
  25 enum {
  26         CD_GPIO = 0,
  27         WP_GPIO,
  28         NUM_GPIOS,
  29 };
  30
  31 struct of_mmc_spi {
  32         int gpios[NUM_GPIOS];
  33         bool alow_gpios[NUM_GPIOS];
  34         struct mmc_spi_platform_data pdata;
  35 };
  36
  37 static struct of_mmc_spi *to_of_mmc_spi(struct device *dev)
  38 {
  39         return container_of(dev->platform_data, struct of_mmc_spi, pdata);
  40 }
  41
  42 static int of_mmc_spi_read_gpio(struct device *dev, int gpio_num)
  43 {
  44         struct of_mmc_spi *oms = to_of_mmc_spi(dev);
  45         bool active_low = oms->alow_gpios[gpio_num];
  46         bool value = gpio_get_value(oms->gpios[gpio_num]);
  47
  48         return active_low ^ value;
  49 }
  50
  51 static int of_mmc_spi_get_cd(struct device *dev)
  52 {
  53         return of_mmc_spi_read_gpio(dev, CD_GPIO);
  54 }
  55
  56 static int of_mmc_spi_get_ro(struct device *dev)
  57 {
  58         return of_mmc_spi_read_gpio(dev, WP_GPIO);
  59 }
  60
  61 struct mmc_spi_platform_data *mmc_spi_get_pdata(struct spi_device *spi)
  62 {
  63         struct device *dev = &spi->dev;
  64         struct device_node *np = dev_archdata_get_node(&dev->archdata);
  65         struct of_mmc_spi *oms;
  66         const u32 *voltage_ranges;
  67         int num_ranges;
  68         int i;
  69         int ret = -EINVAL;
  70
  71         if (dev->platform_data || !np)
  72                 return dev->platform_data;
  73
  74         oms = kzalloc(sizeof(*oms), GFP_KERNEL);
  75         if (!oms)
  76                 return NULL;
  77
  78         voltage_ranges = of_get_property(np, "voltage-ranges", &num_ranges);
  79         num_ranges = num_ranges / sizeof(*voltage_ranges) / 2;
  80         if (!voltage_ranges || !num_ranges) {
  81                 dev_err(dev, "OF: voltage-ranges unspecified\n");
  82                 goto err_ocr;
  83         }
  84
  85         for (i = 0; i < num_ranges; i++) {
  86                 const int j = i * 2;
  87                 u32 mask;
  88
  89                 mask = mmc_vddrange_to_ocrmask(voltage_ranges[j],
  90                                                voltage_ranges[j + 1]);
  91                 if (!mask) {
  92                         ret = -EINVAL;
  93                         dev_err(dev, "OF: voltage-range #%d is invalid\n", i);
  94                         goto err_ocr;
  95                 }
  96                 oms->pdata.ocr_mask |= mask;
  97         }
  98
  99         for (i = 0; i < ARRAY_SIZE(oms->gpios); i++) {
 100                 enum of_gpio_flags gpio_flags;
 101
 102                 oms->gpios[i] = of_get_gpio_flags(np, i, &gpio_flags);
 103                 if (!gpio_is_valid(oms->gpios[i]))
 104                         continue;
 105
 106                 ret = gpio_request(oms->gpios[i], dev->bus_id);
 107                 if (ret < 0) {
 108                         oms->gpios[i] = -EINVAL;
 109                         continue;
 110                 }
 111
 112                 if (gpio_flags & OF_GPIO_ACTIVE_LOW)
 113                         oms->alow_gpios[i] = true;
 114         }
 115
 116         if (gpio_is_valid(oms->gpios[CD_GPIO]))
 117                 oms->pdata.get_cd = of_mmc_spi_get_cd;
 118         if (gpio_is_valid(oms->gpios[WP_GPIO]))
 119                 oms->pdata.get_ro = of_mmc_spi_get_ro;
 120
 121         /* We don't support interrupts yet, let's poll. */
 122         oms->pdata.caps |= MMC_CAP_NEEDS_POLL;
 123
 124         dev->platform_data = &oms->pdata;
 125         return dev->platform_data;
 126 err_ocr:
 127         kfree(oms);
 128         return NULL;
 129 }
 130 EXPORT_SYMBOL(mmc_spi_get_pdata);
 131
 132 void mmc_spi_put_pdata(struct spi_device *spi)
 133 {
 134         struct device *dev = &spi->dev;
 135         struct device_node *np = dev_archdata_get_node(&dev->archdata);
 136         struct of_mmc_spi *oms = to_of_mmc_spi(dev);
 137         int i;
 138
 139         if (!dev->platform_data || !np)
 140                 return;
 141
 142         for (i = 0; i < ARRAY_SIZE(oms->gpios); i++) {
 143                 if (gpio_is_valid(oms->gpios[i]))
 144                         gpio_free(oms->gpios[i]);
 145         }
 146         kfree(oms);
 147         dev->platform_data = NULL;
 148 }
 149 EXPORT_SYMBOL(mmc_spi_put_pdata);