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/irq.h>
  19 #include <linux/gpio.h>
  20 #include <linux/of.h>
  21 #include <linux/of_gpio.h>
  22 #include <linux/of_irq.h>
  23 #include <linux/spi/spi.h>
  24 #include <linux/spi/mmc_spi.h>
  25 #include <linux/mmc/core.h>
  26 #include <linux/mmc/host.h>
  27
  28 MODULE_LICENSE("GPL");
  29
  30 enum {
  31         CD_GPIO = 0,
  32         WP_GPIO,
  33         NUM_GPIOS,
  34 };
  35
  36 struct of_mmc_spi {
  37         int gpios[NUM_GPIOS];
  38         bool alow_gpios[NUM_GPIOS];
  39         int detect_irq;
  40         struct mmc_spi_platform_data pdata;
  41 };
  42
  43 static struct of_mmc_spi *to_of_mmc_spi(struct device *dev)
  44 {
  45         return container_of(dev->platform_data, struct of_mmc_spi, pdata);
  46 }
  47
  48 static int of_mmc_spi_read_gpio(struct device *dev, int gpio_num)
  49 {
  50         struct of_mmc_spi *oms = to_of_mmc_spi(dev);
  51         bool active_low = oms->alow_gpios[gpio_num];
  52         bool value = gpio_get_value(oms->gpios[gpio_num]);
  53
  54         return active_low ^ value;
  55 }
  56
  57 static int of_mmc_spi_get_cd(struct device *dev)
  58 {
  59         return of_mmc_spi_read_gpio(dev, CD_GPIO);
  60 }
  61
  62 static int of_mmc_spi_get_ro(struct device *dev)
  63 {
  64         return of_mmc_spi_read_gpio(dev, WP_GPIO);
  65 }
  66
  67 static int of_mmc_spi_init(struct device *dev,
  68                            irqreturn_t (*irqhandler)(int, void *), void *mmc)
  69 {
  70         struct of_mmc_spi *oms = to_of_mmc_spi(dev);
  71
  72         return request_threaded_irq(oms->detect_irq, NULL, irqhandler, 0,
  73                                     dev_name(dev), mmc);
  74 }
  75
  76 static void of_mmc_spi_exit(struct device *dev, void *mmc)
  77 {
  78         struct of_mmc_spi *oms = to_of_mmc_spi(dev);
  79
  80         free_irq(oms->detect_irq, mmc);
  81 }
  82
  83 struct mmc_spi_platform_data *mmc_spi_get_pdata(struct spi_device *spi)
  84 {
  85         struct device *dev = &spi->dev;
  86         struct device_node *np = dev->of_node;
  87         struct of_mmc_spi *oms;
  88         const u32 *voltage_ranges;
  89         int num_ranges;
  90         int i;
  91         int ret = -EINVAL;
  92
  93         if (dev->platform_data || !np)
  94                 return dev->platform_data;
  95
  96         oms = kzalloc(sizeof(*oms), GFP_KERNEL);
  97         if (!oms)
  98                 return NULL;
  99
 100         voltage_ranges = of_get_property(np, "voltage-ranges", &num_ranges);
 101         num_ranges = num_ranges / sizeof(*voltage_ranges) / 2;
 102         if (!voltage_ranges || !num_ranges) {
 103                 dev_err(dev, "OF: voltage-ranges unspecified\n");
 104                 goto err_ocr;
 105         }
 106
 107         for (i = 0; i < num_ranges; i++) {
 108                 const int j = i * 2;
 109                 u32 mask;
 110
 111                 mask = mmc_vddrange_to_ocrmask(voltage_ranges[j],
 112                                                voltage_ranges[j + 1]);
 113                 if (!mask) {
 114                         ret = -EINVAL;
 115                         dev_err(dev, "OF: voltage-range #%d is invalid\n", i);
 116                         goto err_ocr;
 117                 }
 118                 oms->pdata.ocr_mask |= mask;
 119         }
 120
 121         for (i = 0; i < ARRAY_SIZE(oms->gpios); i++) {
 122                 enum of_gpio_flags gpio_flags;
 123
 124                 oms->gpios[i] = of_get_gpio_flags(np, i, &gpio_flags);
 125                 if (!gpio_is_valid(oms->gpios[i]))
 126                         continue;
 127
 128                 ret = gpio_request(oms->gpios[i], dev_name(dev));
 129                 if (ret < 0) {
 130                         oms->gpios[i] = -EINVAL;
 131                         continue;
 132                 }
 133
 134                 if (gpio_flags & OF_GPIO_ACTIVE_LOW)
 135                         oms->alow_gpios[i] = true;
 136         }
 137
 138         if (gpio_is_valid(oms->gpios[CD_GPIO]))
 139                 oms->pdata.get_cd = of_mmc_spi_get_cd;
 140         if (gpio_is_valid(oms->gpios[WP_GPIO]))
 141                 oms->pdata.get_ro = of_mmc_spi_get_ro;
 142
 143         oms->detect_irq = irq_of_parse_and_map(np, 0);
 144         if (oms->detect_irq != NO_IRQ) {
 145                 oms->pdata.init = of_mmc_spi_init;
 146                 oms->pdata.exit = of_mmc_spi_exit;
 147         } else {
 148                 oms->pdata.caps |= MMC_CAP_NEEDS_POLL;
 149         }
 150
 151         dev->platform_data = &oms->pdata;
 152         return dev->platform_data;
 153 err_ocr:
 154         kfree(oms);
 155         return NULL;
 156 }
 157 EXPORT_SYMBOL(mmc_spi_get_pdata);
 158
 159 void mmc_spi_put_pdata(struct spi_device *spi)
 160 {
 161         struct device *dev = &spi->dev;
 162         struct device_node *np = dev->of_node;
 163         struct of_mmc_spi *oms = to_of_mmc_spi(dev);
 164         int i;
 165
 166         if (!dev->platform_data || !np)
 167                 return;
 168
 169         for (i = 0; i < ARRAY_SIZE(oms->gpios); i++) {
 170                 if (gpio_is_valid(oms->gpios[i]))
 171                         gpio_free(oms->gpios[i]);
 172         }
 173         kfree(oms);
 174         dev->platform_data = NULL;
 175 }
 176 EXPORT_SYMBOL(mmc_spi_put_pdata);