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         int detect_irq;
  38         struct mmc_spi_platform_data pdata;
  39 };
  40
  41 static struct of_mmc_spi *to_of_mmc_spi(struct device *dev)
  42 {
  43         return container_of(dev->platform_data, struct of_mmc_spi, pdata);
  44 }
  45
  46 static int of_mmc_spi_read_gpio(struct device *dev, int gpio_num)
  47 {
  48         struct of_mmc_spi *oms = to_of_mmc_spi(dev);
  49         bool active_low = oms->alow_gpios[gpio_num];
  50         bool value = gpio_get_value(oms->gpios[gpio_num]);
  51
  52         return active_low ^ value;
  53 }
  54
  55 static int of_mmc_spi_get_cd(struct device *dev)
  56 {
  57         return of_mmc_spi_read_gpio(dev, CD_GPIO);
  58 }
  59
  60 static int of_mmc_spi_get_ro(struct device *dev)
  61 {
  62         return of_mmc_spi_read_gpio(dev, WP_GPIO);
  63 }
  64
  65 static int of_mmc_spi_init(struct device *dev,
  66                            irqreturn_t (*irqhandler)(int, void *), void *mmc)
  67 {
  68         struct of_mmc_spi *oms = to_of_mmc_spi(dev);
  69
  70         return request_threaded_irq(oms->detect_irq, NULL, irqhandler, 0,
  71                                     dev_name(dev), mmc);
  72 }
  73
  74 static void of_mmc_spi_exit(struct device *dev, void *mmc)
  75 {
  76         struct of_mmc_spi *oms = to_of_mmc_spi(dev);
  77
  78         free_irq(oms->detect_irq, mmc);
  79 }
  80
  81 struct mmc_spi_platform_data *mmc_spi_get_pdata(struct spi_device *spi)
  82 {
  83         struct device *dev = &spi->dev;
  84         struct device_node *np = dev->of_node;
  85         struct of_mmc_spi *oms;
  86         const u32 *voltage_ranges;
  87         int num_ranges;
  88         int i;
  89         int ret = -EINVAL;
  90
  91         if (dev->platform_data || !np)
  92                 return dev->platform_data;
  93
  94         oms = kzalloc(sizeof(*oms), GFP_KERNEL);
  95         if (!oms)
  96                 return NULL;
  97
  98         voltage_ranges = of_get_property(np, "voltage-ranges", &num_ranges);
  99         num_ranges = num_ranges / sizeof(*voltage_ranges) / 2;
 100         if (!voltage_ranges || !num_ranges) {
 101                 dev_err(dev, "OF: voltage-ranges unspecified\n");
 102                 goto err_ocr;
 103         }
 104
 105         for (i = 0; i < num_ranges; i++) {
 106                 const int j = i * 2;
 107                 u32 mask;
 108
 109                 mask = mmc_vddrange_to_ocrmask(voltage_ranges[j],
 110                                                voltage_ranges[j + 1]);
 111                 if (!mask) {
 112                         ret = -EINVAL;
 113                         dev_err(dev, "OF: voltage-range #%d is invalid\n", i);
 114                         goto err_ocr;
 115                 }
 116                 oms->pdata.ocr_mask |= mask;
 117         }
 118
 119         for (i = 0; i < ARRAY_SIZE(oms->gpios); i++) {
 120                 enum of_gpio_flags gpio_flags;
 121
 122                 oms->gpios[i] = of_get_gpio_flags(np, i, &gpio_flags);
 123                 if (!gpio_is_valid(oms->gpios[i]))
 124                         continue;
 125
 126                 ret = gpio_request(oms->gpios[i], dev_name(dev));
 127                 if (ret < 0) {
 128                         oms->gpios[i] = -EINVAL;
 129                         continue;
 130                 }
 131
 132                 if (gpio_flags & OF_GPIO_ACTIVE_LOW)
 133                         oms->alow_gpios[i] = true;
 134         }
 135
 136         if (gpio_is_valid(oms->gpios[CD_GPIO]))
 137                 oms->pdata.get_cd = of_mmc_spi_get_cd;
 138         if (gpio_is_valid(oms->gpios[WP_GPIO]))
 139                 oms->pdata.get_ro = of_mmc_spi_get_ro;
 140
 141         oms->detect_irq = irq_of_parse_and_map(np, 0);
 142         if (oms->detect_irq != NO_IRQ) {
 143                 oms->pdata.init = of_mmc_spi_init;
 144                 oms->pdata.exit = of_mmc_spi_exit;
 145         } else {
 146                 oms->pdata.caps |= MMC_CAP_NEEDS_POLL;
 147         }
 148
 149         dev->platform_data = &oms->pdata;
 150         return dev->platform_data;
 151 err_ocr:
 152         kfree(oms);
 153         return NULL;
 154 }
 155 EXPORT_SYMBOL(mmc_spi_get_pdata);
 156
 157 void mmc_spi_put_pdata(struct spi_device *spi)
 158 {
 159         struct device *dev = &spi->dev;
 160         struct device_node *np = dev->of_node;
 161         struct of_mmc_spi *oms = to_of_mmc_spi(dev);
 162         int i;
 163
 164         if (!dev->platform_data || !np)
 165                 return;
 166
 167         for (i = 0; i < ARRAY_SIZE(oms->gpios); i++) {
 168                 if (gpio_is_valid(oms->gpios[i]))
 169                         gpio_free(oms->gpios[i]);
 170         }
 171         kfree(oms);
 172         dev->platform_data = NULL;
 173 }
 174 EXPORT_SYMBOL(mmc_spi_put_pdata);