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
32static void digsy_mtc_op_prepare(void *p)
33{
34 /* enable */
35 gpio_set_value(GPIO_EEPROM_OE, value: 0);
36}
37
38static void digsy_mtc_op_finish(void *p)
39{
40 /* disable */
41 gpio_set_value(GPIO_EEPROM_OE, value: 1);
42}
43
44struct 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
50static struct spi_gpio_platform_data eeprom_spi_gpio_data = {
51 .num_chipselect = 1,
52};
53
54static 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
62static 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
77static 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
88static 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 label: "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(table: &eeprom_spi_gpiod_table);
99 spi_register_board_info(info: digsy_mtc_eeprom_info,
100 ARRAY_SIZE(digsy_mtc_eeprom_info));
101 return platform_device_register(&digsy_mtc_eeprom);
102}
103device_initcall(digsy_mtc_eeprom_devices_init);
104

source code of linux/drivers/misc/eeprom/digsy_mtc_eeprom.c