drivers/misc/eeprom/digsy_mtc_eeprom.c

   1 /*
   2  * EEPROMs access control driver for display configuration EEPROMs
   3  * on DigsyMTC board.
   4  *
   5  * (C) 2011 DENX Software Engineering, Anatolij Gustschin <agust@denx.de>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11
  12 #include <linux/gpio.h>
  13 #include <linux/init.h>
  14 #include <linux/platform_device.h>
  15 #include <linux/spi/spi.h>
  16 #include <linux/spi/spi_gpio.h>
  17 #include <linux/eeprom_93xx46.h>
  18
  19 #define GPIO_EEPROM_CLK         216
  20 #define GPIO_EEPROM_CS          210
  21 #define GPIO_EEPROM_DI          217
  22 #define GPIO_EEPROM_DO          249
  23 #define GPIO_EEPROM_OE          255
  24 #define EE_SPI_BUS_NUM  1
  25
  26 static void digsy_mtc_op_prepare(void *p)
  27 {
  28         /* enable */
  29         gpio_set_value(GPIO_EEPROM_OE, 0);
  30 }
  31
  32 static void digsy_mtc_op_finish(void *p)
  33 {
  34         /* disable */
  35         gpio_set_value(GPIO_EEPROM_OE, 1);
  36 }
  37
  38 struct eeprom_93xx46_platform_data digsy_mtc_eeprom_data = {
  39         .flags          = EE_ADDR8,
  40         .prepare        = digsy_mtc_op_prepare,
  41         .finish         = digsy_mtc_op_finish,
  42 };
  43
  44 static struct spi_gpio_platform_data eeprom_spi_gpio_data = {
  45         .sck            = GPIO_EEPROM_CLK,
  46         .mosi           = GPIO_EEPROM_DI,
  47         .miso           = GPIO_EEPROM_DO,
  48         .num_chipselect = 1,
  49 };
  50
  51 static struct platform_device digsy_mtc_eeprom = {
  52         .name   = "spi_gpio",
  53         .id     = EE_SPI_BUS_NUM,
  54         .dev    = {
  55                 .platform_data  = &eeprom_spi_gpio_data,
  56         },
  57 };
  58
  59 static struct spi_board_info digsy_mtc_eeprom_info[] __initdata = {
  60         {
  61                 .modalias               = "93xx46",
  62                 .max_speed_hz           = 1000000,
  63                 .bus_num                = EE_SPI_BUS_NUM,
  64                 .chip_select            = 0,
  65                 .mode                   = SPI_MODE_0,
  66                 .controller_data        = (void *)GPIO_EEPROM_CS,
  67                 .platform_data          = &digsy_mtc_eeprom_data,
  68         },
  69 };
  70
  71 static int __init digsy_mtc_eeprom_devices_init(void)
  72 {
  73         int ret;
  74
  75         ret = gpio_request_one(GPIO_EEPROM_OE, GPIOF_OUT_INIT_HIGH,
  76                                 "93xx46 EEPROMs OE");
  77         if (ret) {
  78                 pr_err("can't request gpio %d\n", GPIO_EEPROM_OE);
  79                 return ret;
  80         }
  81         spi_register_board_info(digsy_mtc_eeprom_info,
  82                                 ARRAY_SIZE(digsy_mtc_eeprom_info));
  83         return platform_device_register(&digsy_mtc_eeprom);
  84 }
  85 device_initcall(digsy_mtc_eeprom_devices_init);