misc/eeprom/digsy_mtc_eeprom.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * EEPROMs access control driver for display configuration EEPROMs
0004  * on DigsyMTC board.
0005  *
0006  * (C) 2011 DENX Software Engineering, Anatolij Gustschin <agust@denx.de>
0007  *
0008  * FIXME: this driver is used on a device-tree probed platform: it
0009  * should be defined as a bit-banged SPI device and probed from the device
0010  * tree and not like this with static grabbing of a few numbered GPIO
0011  * lines at random.
0012  *
0013  * Add proper SPI and EEPROM in arch/powerpc/boot/dts/digsy_mtc.dts
0014  * and delete this driver.
0015  */
0016
0017 #include <linux/gpio.h>
0018 #include <linux/gpio/machine.h>
0019 #include <linux/init.h>
0020 #include <linux/platform_device.h>
0021 #include <linux/spi/spi.h>
0022 #include <linux/spi/spi_gpio.h>
0023 #include <linux/eeprom_93xx46.h>
0024
0025 #define GPIO_EEPROM_CLK     216
0026 #define GPIO_EEPROM_CS      210
0027 #define GPIO_EEPROM_DI      217
0028 #define GPIO_EEPROM_DO      249
0029 #define GPIO_EEPROM_OE      255
0030 #define EE_SPI_BUS_NUM  1
0031
0032 static void digsy_mtc_op_prepare(void *p)
0033 {
0034     /* enable */
0035     gpio_set_value(GPIO_EEPROM_OE, 0);
0036 }
0037
0038 static void digsy_mtc_op_finish(void *p)
0039 {
0040     /* disable */
0041     gpio_set_value(GPIO_EEPROM_OE, 1);
0042 }
0043
0044 struct eeprom_93xx46_platform_data digsy_mtc_eeprom_data = {
0045     .flags      = EE_ADDR8,
0046     .prepare    = digsy_mtc_op_prepare,
0047     .finish     = digsy_mtc_op_finish,
0048 };
0049
0050 static struct spi_gpio_platform_data eeprom_spi_gpio_data = {
0051     .num_chipselect = 1,
0052 };
0053
0054 static struct platform_device digsy_mtc_eeprom = {
0055     .name   = "spi_gpio",
0056     .id = EE_SPI_BUS_NUM,
0057     .dev    = {
0058         .platform_data  = &eeprom_spi_gpio_data,
0059     },
0060 };
0061
0062 static struct gpiod_lookup_table eeprom_spi_gpiod_table = {
0063     .dev_id         = "spi_gpio",
0064     .table          = {
0065         GPIO_LOOKUP("gpio@b00", GPIO_EEPROM_CLK,
0066                 "sck", GPIO_ACTIVE_HIGH),
0067         GPIO_LOOKUP("gpio@b00", GPIO_EEPROM_DI,
0068                 "mosi", GPIO_ACTIVE_HIGH),
0069         GPIO_LOOKUP("gpio@b00", GPIO_EEPROM_DO,
0070                 "miso", GPIO_ACTIVE_HIGH),
0071         GPIO_LOOKUP("gpio@b00", GPIO_EEPROM_CS,
0072                 "cs", GPIO_ACTIVE_HIGH),
0073         { },
0074     },
0075 };
0076
0077 static struct spi_board_info digsy_mtc_eeprom_info[] __initdata = {
0078     {
0079         .modalias       = "93xx46",
0080         .max_speed_hz       = 1000000,
0081         .bus_num        = EE_SPI_BUS_NUM,
0082         .chip_select        = 0,
0083         .mode           = SPI_MODE_0,
0084         .platform_data      = &digsy_mtc_eeprom_data,
0085     },
0086 };
0087
0088 static int __init digsy_mtc_eeprom_devices_init(void)
0089 {
0090     int ret;
0091
0092     ret = gpio_request_one(GPIO_EEPROM_OE, GPIOF_OUT_INIT_HIGH,
0093                 "93xx46 EEPROMs OE");
0094     if (ret) {
0095         pr_err("can't request gpio %d\n", GPIO_EEPROM_OE);
0096         return ret;
0097     }
0098     gpiod_add_lookup_table(&eeprom_spi_gpiod_table);
0099     spi_register_board_info(digsy_mtc_eeprom_info,
0100                 ARRAY_SIZE(digsy_mtc_eeprom_info));
0101     return platform_device_register(&digsy_mtc_eeprom);
0102 }
0103 device_initcall(digsy_mtc_eeprom_devices_init);