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 /* For archs that don't support NO_IRQ (such as mips), provide a dummy value */
  29 #ifndef NO_IRQ
  30 #define NO_IRQ 0
  31 #endif
  32
  33 MODULE_LICENSE("GPL");
  34
  35 enum {
  36         CD_GPIO = 0,
  37         WP_GPIO,
  38         NUM_GPIOS,
  39 };
  40
  41 struct of_mmc_spi {
  42         int gpios[NUM_GPIOS];
  43         bool alow_gpios[NUM_GPIOS];
  44         int detect_irq;
  45         struct mmc_spi_platform_data pdata;
  46 };
  47
  48 static struct of_mmc_spi *to_of_mmc_spi(struct device *dev)
  49 {
  50         return container_of(dev->platform_data, struct of_mmc_spi, pdata);
  51 }
  52
  53 static int of_mmc_spi_read_gpio(struct device *dev, int gpio_num)
  54 {
  55         struct of_mmc_spi *oms = to_of_mmc_spi(dev);
  56         bool active_low = oms->alow_gpios[gpio_num];
  57         bool value = gpio_get_value(oms->gpios[gpio_num]);
  58
  59         return active_low ^ value;
  60 }
  61
  62 static int of_mmc_spi_get_cd(struct device *dev)
  63 {
  64         return of_mmc_spi_read_gpio(dev, CD_GPIO);
  65 }
  66
  67 static int of_mmc_spi_get_ro(struct device *dev)
  68 {
  69         return of_mmc_spi_read_gpio(dev, WP_GPIO);
  70 }
  71
  72 static int of_mmc_spi_init(struct device *dev,
  73                            irqreturn_t (*irqhandler)(int, void *), void *mmc)
  74 {
  75         struct of_mmc_spi *oms = to_of_mmc_spi(dev);
  76
  77         return request_threaded_irq(oms->detect_irq, NULL, irqhandler, 0,
  78                                     dev_name(dev), mmc);
  79 }
  80
  81 static void of_mmc_spi_exit(struct device *dev, void *mmc)
  82 {
  83         struct of_mmc_spi *oms = to_of_mmc_spi(dev);
  84
  85         free_irq(oms->detect_irq, mmc);
  86 }
  87
  88 struct mmc_spi_platform_data *mmc_spi_get_pdata(struct spi_device *spi)
  89 {
  90         struct device *dev = &spi->dev;
  91         struct device_node *np = dev->of_node;
  92         struct of_mmc_spi *oms;
  93         const u32 *voltage_ranges;
  94         int num_ranges;
  95         int i;
  96         int ret = -EINVAL;
  97
  98         if (dev->platform_data || !np)
  99                 return dev->platform_data;
 100
 101         oms = kzalloc(sizeof(*oms), GFP_KERNEL);
 102         if (!oms)
 103                 return NULL;
 104
 105         voltage_ranges = of_get_property(np, "voltage-ranges", &num_ranges);
 106         num_ranges = num_ranges / sizeof(*voltage_ranges) / 2;
 107         if (!voltage_ranges || !num_ranges) {
 108                 dev_err(dev, "OF: voltage-ranges unspecified\n");
 109                 goto err_ocr;
 110         }
 111
 112         for (i = 0; i < num_ranges; i++) {
 113                 const int j = i * 2;
 114                 u32 mask;
 115
 116                 mask = mmc_vddrange_to_ocrmask(be32_to_cpu(voltage_ranges[j]),
 117                                                be32_to_cpu(voltage_ranges[j + 1]));
 118                 if (!mask) {
 119                         ret = -EINVAL;
 120                         dev_err(dev, "OF: voltage-range #%d is invalid\n", i);
 121                         goto err_ocr;
 122                 }
 123                 oms->pdata.ocr_mask |= mask;
 124         }
 125
 126         for (i = 0; i < ARRAY_SIZE(oms->gpios); i++) {
 127                 enum of_gpio_flags gpio_flags;
 128
 129                 oms->gpios[i] = of_get_gpio_flags(np, i, &gpio_flags);
 130                 if (!gpio_is_valid(oms->gpios[i]))
 131                         continue;
 132
 133                 ret = gpio_request(oms->gpios[i], dev_name(dev));
 134                 if (ret < 0) {
 135                         oms->gpios[i] = -EINVAL;
 136                         continue;
 137                 }
 138
 139                 if (gpio_flags & OF_GPIO_ACTIVE_LOW)
 140                         oms->alow_gpios[i] = true;
 141         }
 142
 143         if (gpio_is_valid(oms->gpios[CD_GPIO]))
 144                 oms->pdata.get_cd = of_mmc_spi_get_cd;
 145         if (gpio_is_valid(oms->gpios[WP_GPIO]))
 146                 oms->pdata.get_ro = of_mmc_spi_get_ro;
 147
 148         oms->detect_irq = irq_of_parse_and_map(np, 0);
 149         if (oms->detect_irq != NO_IRQ) {
 150                 oms->pdata.init = of_mmc_spi_init;
 151                 oms->pdata.exit = of_mmc_spi_exit;
 152         } else {
 153                 oms->pdata.caps |= MMC_CAP_NEEDS_POLL;
 154         }
 155
 156         dev->platform_data = &oms->pdata;
 157         return dev->platform_data;
 158 err_ocr:
 159         kfree(oms);
 160         return NULL;
 161 }
 162 EXPORT_SYMBOL(mmc_spi_get_pdata);
 163
 164 void mmc_spi_put_pdata(struct spi_device *spi)
 165 {
 166         struct device *dev = &spi->dev;
 167         struct device_node *np = dev->of_node;
 168         struct of_mmc_spi *oms = to_of_mmc_spi(dev);
 169         int i;
 170
 171         if (!dev->platform_data || !np)
 172                 return;
 173
 174         for (i = 0; i < ARRAY_SIZE(oms->gpios); i++) {
 175                 if (gpio_is_valid(oms->gpios[i]))
 176                         gpio_free(oms->gpios[i]);
 177         }
 178         kfree(oms);
 179         dev->platform_data = NULL;
 180 }
 181 EXPORT_SYMBOL(mmc_spi_put_pdata);