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