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 
digsy_mtc_op_prepare(void * p)32 static void digsy_mtc_op_prepare(void *p)
33 {
34 	/* enable */
35 	gpio_set_value(GPIO_EEPROM_OE, 0);
36 }
37 
digsy_mtc_op_finish(void * p)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 | EE_SIZE1K,
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 
digsy_mtc_eeprom_devices_init(void)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);
104