1 /*
2  * EEPROMs access control driver for display configuration EEPROMs
3  * on DigsyMTC board.
4  *
5  * (C) 2011 DENX Software Engineering, Anatolij Gustschin <agust@denx.de>
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License version 2 as
9  * published by the Free Software Foundation.
10  *
11  * FIXME: this driver is used on a device-tree probed platform: it
12  * should be defined as a bit-banged SPI device and probed from the device
13  * tree and not like this with static grabbing of a few numbered GPIO
14  * lines at random.
15  *
16  * Add proper SPI and EEPROM in arch/powerpc/boot/dts/digsy_mtc.dts
17  * and delete this driver.
18  */
19 
20 #include <linux/gpio.h>
21 #include <linux/gpio/machine.h>
22 #include <linux/init.h>
23 #include <linux/platform_device.h>
24 #include <linux/spi/spi.h>
25 #include <linux/spi/spi_gpio.h>
26 #include <linux/eeprom_93xx46.h>
27 
28 #define GPIO_EEPROM_CLK		216
29 #define GPIO_EEPROM_CS		210
30 #define GPIO_EEPROM_DI		217
31 #define GPIO_EEPROM_DO		249
32 #define GPIO_EEPROM_OE		255
33 #define EE_SPI_BUS_NUM	1
34 
35 static void digsy_mtc_op_prepare(void *p)
36 {
37 	/* enable */
38 	gpio_set_value(GPIO_EEPROM_OE, 0);
39 }
40 
41 static void digsy_mtc_op_finish(void *p)
42 {
43 	/* disable */
44 	gpio_set_value(GPIO_EEPROM_OE, 1);
45 }
46 
47 struct eeprom_93xx46_platform_data digsy_mtc_eeprom_data = {
48 	.flags		= EE_ADDR8,
49 	.prepare	= digsy_mtc_op_prepare,
50 	.finish		= digsy_mtc_op_finish,
51 };
52 
53 static struct spi_gpio_platform_data eeprom_spi_gpio_data = {
54 	.num_chipselect	= 1,
55 };
56 
57 static struct platform_device digsy_mtc_eeprom = {
58 	.name	= "spi_gpio",
59 	.id	= EE_SPI_BUS_NUM,
60 	.dev	= {
61 		.platform_data	= &eeprom_spi_gpio_data,
62 	},
63 };
64 
65 static struct gpiod_lookup_table eeprom_spi_gpiod_table = {
66 	.dev_id         = "spi_gpio",
67 	.table          = {
68 		GPIO_LOOKUP("gpio@b00", GPIO_EEPROM_CLK,
69 			    "sck", GPIO_ACTIVE_HIGH),
70 		GPIO_LOOKUP("gpio@b00", GPIO_EEPROM_DI,
71 			    "mosi", GPIO_ACTIVE_HIGH),
72 		GPIO_LOOKUP("gpio@b00", GPIO_EEPROM_DO,
73 			    "miso", GPIO_ACTIVE_HIGH),
74 		GPIO_LOOKUP("gpio@b00", GPIO_EEPROM_CS,
75 			    "cs", GPIO_ACTIVE_HIGH),
76 		{ },
77 	},
78 };
79 
80 static struct spi_board_info digsy_mtc_eeprom_info[] __initdata = {
81 	{
82 		.modalias		= "93xx46",
83 		.max_speed_hz		= 1000000,
84 		.bus_num		= EE_SPI_BUS_NUM,
85 		.chip_select		= 0,
86 		.mode			= SPI_MODE_0,
87 		.platform_data		= &digsy_mtc_eeprom_data,
88 	},
89 };
90 
91 static int __init digsy_mtc_eeprom_devices_init(void)
92 {
93 	int ret;
94 
95 	ret = gpio_request_one(GPIO_EEPROM_OE, GPIOF_OUT_INIT_HIGH,
96 				"93xx46 EEPROMs OE");
97 	if (ret) {
98 		pr_err("can't request gpio %d\n", GPIO_EEPROM_OE);
99 		return ret;
100 	}
101 	gpiod_add_lookup_table(&eeprom_spi_gpiod_table);
102 	spi_register_board_info(digsy_mtc_eeprom_info,
103 				ARRAY_SIZE(digsy_mtc_eeprom_info));
104 	return platform_device_register(&digsy_mtc_eeprom);
105 }
106 device_initcall(digsy_mtc_eeprom_devices_init);
107