digsy_mtc_eeprom.c

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/*
 * EEPROMs access control driver for display configuration EEPROMs
 * on DigsyMTC board.
 *
 * (C) 2011 DENX Software Engineering, Anatolij Gustschin <[email protected]>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/gpio.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/spi/spi.h>
#include <linux/spi/spi_gpio.h>
#include <linux/eeprom_93xx46.h>

#define GPIO_EEPROM_CLK     216
#define GPIO_EEPROM_CS      210
#define GPIO_EEPROM_DI      217
#define GPIO_EEPROM_DO      249
#define GPIO_EEPROM_OE      255
#define EE_SPI_BUS_NUM  1

static void digsy_mtc_op_prepare(void *p)
{
    /* enable */
    gpio_set_value(GPIO_EEPROM_OE, 0);
}

static void digsy_mtc_op_finish(void *p)
{
    /* disable */
    gpio_set_value(GPIO_EEPROM_OE, 1);
}

struct eeprom_93xx46_platform_data digsy_mtc_eeprom_data = {
    .flags      = EE_ADDR8,
    .prepare    = digsy_mtc_op_prepare,
    .finish     = digsy_mtc_op_finish,
};

static struct spi_gpio_platform_data eeprom_spi_gpio_data = {
    .sck        = GPIO_EEPROM_CLK,
    .mosi       = GPIO_EEPROM_DI,
    .miso       = GPIO_EEPROM_DO,
    .num_chipselect = 1,
};

static struct platform_device digsy_mtc_eeprom = {
    .name   = "spi_gpio",
    .id = EE_SPI_BUS_NUM,
    .dev    = {
        .platform_data  = &eeprom_spi_gpio_data,
    },
};

static struct spi_board_info digsy_mtc_eeprom_info[] __initdata = {
    {
        .modalias       = "93xx46",
        .max_speed_hz       = 1000000,
        .bus_num        = EE_SPI_BUS_NUM,
        .chip_select        = 0,
        .mode           = SPI_MODE_0,
        .controller_data    = (void *)GPIO_EEPROM_CS,
        .platform_data      = &digsy_mtc_eeprom_data,
    },
};

static int __init digsy_mtc_eeprom_devices_init(void)
{
    int ret;

    ret = gpio_request_one(GPIO_EEPROM_OE, GPIOF_OUT_INIT_HIGH,
                "93xx46 EEPROMs OE");
    if (ret) {
        pr_err("can't request gpio %d\n", GPIO_EEPROM_OE);
        return ret;
    }
    spi_register_board_info(digsy_mtc_eeprom_info,
                ARRAY_SIZE(digsy_mtc_eeprom_info));
    return platform_device_register(&digsy_mtc_eeprom);
}
device_initcall(digsy_mtc_eeprom_devices_init);