drivers/misc/eeprom/digsy_mtc_eeprom.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * EEPROMs access control driver for display configuration EEPROMs
   4  * on DigsyMTC board.
   5  *
   6  * (C) 2011 DENX Software Engineering, Anatolij Gustschin <agust@denx.de>
   7  *
   8  * FIXME: this driver is used on a device-tree probed platform: it
   9  * should be defined as a bit-banged SPI device and probed from the device
  10  * tree and not like this with static grabbing of a few numbered GPIO
  11  * lines at random.
  12  *
  13  * Add proper SPI and EEPROM in arch/powerpc/boot/dts/digsy_mtc.dts
  14  * and delete this driver.
  15  */
  16
  17 #include <linux/gpio.h>
  18 #include <linux/gpio/machine.h>
  19 #include <linux/init.h>
  20 #include <linux/platform_device.h>
  21 #include <linux/spi/spi.h>
  22 #include <linux/spi/spi_gpio.h>
  23 #include <linux/eeprom_93xx46.h>
  24
  25 #define GPIO_EEPROM_CLK         216
  26 #define GPIO_EEPROM_CS          210
  27 #define GPIO_EEPROM_DI          217
  28 #define GPIO_EEPROM_DO          249
  29 #define GPIO_EEPROM_OE          255
  30 #define EE_SPI_BUS_NUM  1
  31
  32 static void digsy_mtc_op_prepare(void *p)
  33 {
  34         /* enable */
  35         gpio_set_value(GPIO_EEPROM_OE, 0);
  36 }
  37
  38 static void digsy_mtc_op_finish(void *p)
  39 {
  40         /* disable */
  41         gpio_set_value(GPIO_EEPROM_OE, 1);
  42 }
  43
  44 struct eeprom_93xx46_platform_data digsy_mtc_eeprom_data = {
  45         .flags          = EE_ADDR8,
  46         .prepare        = digsy_mtc_op_prepare,
  47         .finish         = digsy_mtc_op_finish,
  48 };
  49
  50 static struct spi_gpio_platform_data eeprom_spi_gpio_data = {
  51         .num_chipselect = 1,
  52 };
  53
  54 static struct platform_device digsy_mtc_eeprom = {
  55         .name   = "spi_gpio",
  56         .id     = EE_SPI_BUS_NUM,
  57         .dev    = {
  58                 .platform_data  = &eeprom_spi_gpio_data,
  59         },
  60 };
  61
  62 static struct gpiod_lookup_table eeprom_spi_gpiod_table = {
  63         .dev_id         = "spi_gpio",
  64         .table          = {
  65                 GPIO_LOOKUP("gpio@b00", GPIO_EEPROM_CLK,
  66                             "sck", GPIO_ACTIVE_HIGH),
  67                 GPIO_LOOKUP("gpio@b00", GPIO_EEPROM_DI,
  68                             "mosi", GPIO_ACTIVE_HIGH),
  69                 GPIO_LOOKUP("gpio@b00", GPIO_EEPROM_DO,
  70                             "miso", GPIO_ACTIVE_HIGH),
  71                 GPIO_LOOKUP("gpio@b00", GPIO_EEPROM_CS,
  72                             "cs", GPIO_ACTIVE_HIGH),
  73                 { },
  74         },
  75 };
  76
  77 static struct spi_board_info digsy_mtc_eeprom_info[] __initdata = {
  78         {
  79                 .modalias               = "93xx46",
  80                 .max_speed_hz           = 1000000,
  81                 .bus_num                = EE_SPI_BUS_NUM,
  82                 .chip_select            = 0,
  83                 .mode                   = SPI_MODE_0,
  84                 .platform_data          = &digsy_mtc_eeprom_data,
  85         },
  86 };
  87
  88 static int __init digsy_mtc_eeprom_devices_init(void)
  89 {
  90         int ret;
  91
  92         ret = gpio_request_one(GPIO_EEPROM_OE, GPIOF_OUT_INIT_HIGH,
  93                                 "93xx46 EEPROMs OE");
  94         if (ret) {
  95                 pr_err("can't request gpio %d\n", GPIO_EEPROM_OE);
  96                 return ret;
  97         }
  98         gpiod_add_lookup_table(&eeprom_spi_gpiod_table);
  99         spi_register_board_info(digsy_mtc_eeprom_info,
 100                                 ARRAY_SIZE(digsy_mtc_eeprom_info));
 101         return platform_device_register(&digsy_mtc_eeprom);
 102 }
 103 device_initcall(digsy_mtc_eeprom_devices_init);