1 /*
2  * Hitachi tx18d42vm LVDS LCD panel driver
3  *
4  * (C) Copyright 2015 Hans de Goede <hdegoede@redhat.com>
5  *
6  * SPDX-License-Identifier:	GPL-2.0+
7  */
8 
9 #include <common.h>
10 
11 #include <asm/gpio.h>
12 #include <errno.h>
13 
14 /*
15  * Very simple write only SPI support, this does not use the generic SPI infra
16  * because that assumes R/W SPI, requiring a MISO pin. Also the necessary glue
17  * code alone would be larger then this minimal version.
18  */
19 static void lcd_panel_spi_write(int cs, int clk, int mosi,
20 				unsigned int data, int bits)
21 {
22 	int i, offset;
23 
24 	gpio_direction_output(cs, 0);
25 	for (i = 0; i < bits; i++) {
26 		gpio_direction_output(clk, 0);
27 		offset = (bits - 1) - i;
28 		gpio_direction_output(mosi, (data >> offset) & 1);
29 		udelay(2);
30 		gpio_direction_output(clk, 1);
31 		udelay(2);
32 	}
33 	gpio_direction_output(cs, 1);
34 	udelay(2);
35 }
36 
37 int hitachi_tx18d42vm_init(void)
38 {
39 	const u16 init_data[] = {
40 		0x0029,		/* reset */
41 		0x0025,		/* standby */
42 		0x0840,		/* enable normally black */
43 		0x0430,		/* enable FRC/dither */
44 		0x385f,		/* enter test mode(1) */
45 		0x3ca4,		/* enter test mode(2) */
46 		0x3409,		/* enable SDRRS, enlarge OE width */
47 		0x4041,		/* adopt 2 line / 1 dot */
48 	};
49 	int i, cs, clk, mosi, ret = 0;
50 
51 	cs = name_to_gpio(CONFIG_VIDEO_LCD_SPI_CS);
52 	clk = name_to_gpio(CONFIG_VIDEO_LCD_SPI_SCLK);
53 	mosi = name_to_gpio(CONFIG_VIDEO_LCD_SPI_MOSI);
54 
55 	if (cs == -1 || clk == -1 || mosi == 1) {
56 		printf("Error tx18d42vm spi gpio config is invalid\n");
57 		return -EINVAL;
58 	}
59 
60 	if (gpio_request(cs, "tx18d42vm-spi-cs") != 0 ||
61 	    gpio_request(clk, "tx18d42vm-spi-clk") != 0 ||
62 	    gpio_request(mosi, "tx18d42vm-spi-mosi") != 0) {
63 		printf("Error cannot request tx18d42vm spi gpios\n");
64 		ret = -EBUSY;
65 		goto out;
66 	}
67 
68 	for (i = 0; i < ARRAY_SIZE(init_data); i++)
69 		lcd_panel_spi_write(cs, clk, mosi, init_data[i], 16);
70 
71 	mdelay(50); /* All the tx18d42vm drivers have a delay here ? */
72 
73 	lcd_panel_spi_write(cs, clk, mosi, 0x00ad, 16); /* display on */
74 
75 out:
76 	gpio_free(mosi);
77 	gpio_free(clk);
78 	gpio_free(cs);
79 
80 	return ret;
81 }
82