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Both displays on digsy_mtc board obtain their configuration from microwire EEPROMs which are connected to the SoC over GPIO lines. We need an easy way to access the EEPROMs to write the needed display configuration or to read out the currently programmed configuration. The generic eeprom_93xx46 SPI driver added by previous patch allows EEPROM access over sysfs. Using the simple driver added by this patch we provide used GPIO interface and access control description on the board for generic eeprom_93xx46 driver and spi_gpio driver. Signed-off-by: Anatolij Gustschin <agust@denx.de> Cc: Jonathan Cameron <jic23@cam.ac.uk> Cc: Grant Likely <grant.likely@secretlab.ca> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
86 lines
2.0 KiB
C
86 lines
2.0 KiB
C
/*
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* EEPROMs access control driver for display configuration EEPROMs
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* on DigsyMTC board.
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*
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* (C) 2011 DENX Software Engineering, Anatolij Gustschin <agust@denx.de>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/gpio.h>
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#include <linux/init.h>
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#include <linux/platform_device.h>
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#include <linux/spi/spi.h>
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#include <linux/spi/spi_gpio.h>
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#include <linux/eeprom_93xx46.h>
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#define GPIO_EEPROM_CLK 216
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#define GPIO_EEPROM_CS 210
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#define GPIO_EEPROM_DI 217
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#define GPIO_EEPROM_DO 249
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#define GPIO_EEPROM_OE 255
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#define EE_SPI_BUS_NUM 1
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static void digsy_mtc_op_prepare(void *p)
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{
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/* enable */
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gpio_set_value(GPIO_EEPROM_OE, 0);
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}
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static void digsy_mtc_op_finish(void *p)
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{
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/* disable */
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gpio_set_value(GPIO_EEPROM_OE, 1);
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}
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struct eeprom_93xx46_platform_data digsy_mtc_eeprom_data = {
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.flags = EE_ADDR8,
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.prepare = digsy_mtc_op_prepare,
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.finish = digsy_mtc_op_finish,
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};
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static struct spi_gpio_platform_data eeprom_spi_gpio_data = {
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.sck = GPIO_EEPROM_CLK,
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.mosi = GPIO_EEPROM_DI,
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.miso = GPIO_EEPROM_DO,
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.num_chipselect = 1,
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};
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static struct platform_device digsy_mtc_eeprom = {
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.name = "spi_gpio",
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.id = EE_SPI_BUS_NUM,
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.dev = {
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.platform_data = &eeprom_spi_gpio_data,
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},
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};
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static struct spi_board_info digsy_mtc_eeprom_info[] __initdata = {
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{
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.modalias = "93xx46",
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.max_speed_hz = 1000000,
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.bus_num = EE_SPI_BUS_NUM,
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.chip_select = 0,
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.mode = SPI_MODE_0,
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.controller_data = (void *)GPIO_EEPROM_CS,
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.platform_data = &digsy_mtc_eeprom_data,
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},
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};
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static int __init digsy_mtc_eeprom_devices_init(void)
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{
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int ret;
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ret = gpio_request_one(GPIO_EEPROM_OE, GPIOF_OUT_INIT_HIGH,
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"93xx46 EEPROMs OE");
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if (ret) {
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pr_err("can't request gpio %d\n", GPIO_EEPROM_OE);
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return ret;
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}
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spi_register_board_info(digsy_mtc_eeprom_info,
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ARRAY_SIZE(digsy_mtc_eeprom_info));
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return platform_device_register(&digsy_mtc_eeprom);
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}
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device_initcall(digsy_mtc_eeprom_devices_init);
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