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  * FIXME: this driver is used on a device-tree probed platform: it
  12  * should be defined as a bit-banged SPI device and probed from the device
  13  * tree and not like this with static grabbing of a few numbered GPIO
  14  * lines at random.
  15  *
  16  * Add proper SPI and EEPROM in arch/powerpc/boot/dts/digsy_mtc.dts
  17  * and delete this driver.
  18  */
  19
  20 #include <linux/gpio.h>
  21 #include <linux/gpio/machine.h>
  22 #include <linux/init.h>
  23 #include <linux/platform_device.h>
  24 #include <linux/spi/spi.h>
  25 #include <linux/spi/spi_gpio.h>
  26 #include <linux/eeprom_93xx46.h>
  27
  28 #define GPIO_EEPROM_CLK         216
  29 #define GPIO_EEPROM_CS          210
  30 #define GPIO_EEPROM_DI          217
  31 #define GPIO_EEPROM_DO          249
  32 #define GPIO_EEPROM_OE          255
  33 #define EE_SPI_BUS_NUM  1
  34
  35 static void digsy_mtc_op_prepare(void *p)
  36 {
  37         /* enable */
  38         gpio_set_value(GPIO_EEPROM_OE, 0);
  39 }
  40
  41 static void digsy_mtc_op_finish(void *p)
  42 {
  43         /* disable */
  44         gpio_set_value(GPIO_EEPROM_OE, 1);
  45 }
  46
  47 struct eeprom_93xx46_platform_data digsy_mtc_eeprom_data = {
  48         .flags          = EE_ADDR8,
  49         .prepare        = digsy_mtc_op_prepare,
  50         .finish         = digsy_mtc_op_finish,
  51 };
  52
  53 static struct spi_gpio_platform_data eeprom_spi_gpio_data = {
  54         .num_chipselect = 1,
  55 };
  56
  57 static struct platform_device digsy_mtc_eeprom = {
  58         .name   = "spi_gpio",
  59         .id     = EE_SPI_BUS_NUM,
  60         .dev    = {
  61                 .platform_data  = &eeprom_spi_gpio_data,
  62         },
  63 };
  64
  65 static struct gpiod_lookup_table eeprom_spi_gpiod_table = {
  66         .dev_id         = "spi_gpio",
  67         .table          = {
  68                 GPIO_LOOKUP("gpio@b00", GPIO_EEPROM_CLK,
  69                             "sck", GPIO_ACTIVE_HIGH),
  70                 GPIO_LOOKUP("gpio@b00", GPIO_EEPROM_DI,
  71                             "mosi", GPIO_ACTIVE_HIGH),
  72                 GPIO_LOOKUP("gpio@b00", GPIO_EEPROM_DO,
  73                             "miso", GPIO_ACTIVE_HIGH),
  74                 GPIO_LOOKUP("gpio@b00", GPIO_EEPROM_CS,
  75                             "cs", GPIO_ACTIVE_HIGH),
  76                 { },
  77         },
  78 };
  79
  80 static struct spi_board_info digsy_mtc_eeprom_info[] __initdata = {
  81         {
  82                 .modalias               = "93xx46",
  83                 .max_speed_hz           = 1000000,
  84                 .bus_num                = EE_SPI_BUS_NUM,
  85                 .chip_select            = 0,
  86                 .mode                   = SPI_MODE_0,
  87                 .platform_data          = &digsy_mtc_eeprom_data,
  88         },
  89 };
  90
  91 static int __init digsy_mtc_eeprom_devices_init(void)
  92 {
  93         int ret;
  94
  95         ret = gpio_request_one(GPIO_EEPROM_OE, GPIOF_OUT_INIT_HIGH,
  96                                 "93xx46 EEPROMs OE");
  97         if (ret) {
  98                 pr_err("can't request gpio %d\n", GPIO_EEPROM_OE);
  99                 return ret;
 100         }
 101         gpiod_add_lookup_table(&eeprom_spi_gpiod_table);
 102         spi_register_board_info(digsy_mtc_eeprom_info,
 103                                 ARRAY_SIZE(digsy_mtc_eeprom_info));
 104         return platform_device_register(&digsy_mtc_eeprom);
 105 }
 106 device_initcall(digsy_mtc_eeprom_devices_init);