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 #include <malloc.h>
10 #include <linux/delay.h>
11
12 #include <asm/gpio.h>
13 #include <errno.h>
14
15 /*
16 * Very simple write only SPI support, this does not use the generic SPI infra
17 * because that assumes R/W SPI, requiring a MISO pin. Also the necessary glue
18 * code alone would be larger then this minimal version.
19 */
lcd_panel_spi_write(int cs,int clk,int mosi,unsigned int data,int bits)20 static void lcd_panel_spi_write(int cs, int clk, int mosi,
21 unsigned int data, int bits)
22 {
23 int i, offset;
24
25 gpio_direction_output(cs, 0);
26 for (i = 0; i < bits; i++) {
27 gpio_direction_output(clk, 0);
28 offset = (bits - 1) - i;
29 gpio_direction_output(mosi, (data >> offset) & 1);
30 udelay(2);
31 gpio_direction_output(clk, 1);
32 udelay(2);
33 }
34 gpio_direction_output(cs, 1);
35 udelay(2);
36 }
37
hitachi_tx18d42vm_init(void)38 int hitachi_tx18d42vm_init(void)
39 {
40 const u16 init_data[] = {
41 0x0029, /* reset */
42 0x0025, /* standby */
43 0x0840, /* enable normally black */
44 0x0430, /* enable FRC/dither */
45 0x385f, /* enter test mode(1) */
46 0x3ca4, /* enter test mode(2) */
47 0x3409, /* enable SDRRS, enlarge OE width */
48 0x4041, /* adopt 2 line / 1 dot */
49 };
50 int i, cs, clk, mosi, ret = 0;
51
52 cs = name_to_gpio(CONFIG_VIDEO_LCD_SPI_CS);
53 clk = name_to_gpio(CONFIG_VIDEO_LCD_SPI_SCLK);
54 mosi = name_to_gpio(CONFIG_VIDEO_LCD_SPI_MOSI);
55
56 if (cs == -1 || clk == -1 || mosi == 1) {
57 printf("Error tx18d42vm spi gpio config is invalid\n");
58 return -EINVAL;
59 }
60
61 if (gpio_request(cs, "tx18d42vm-spi-cs") != 0 ||
62 gpio_request(clk, "tx18d42vm-spi-clk") != 0 ||
63 gpio_request(mosi, "tx18d42vm-spi-mosi") != 0) {
64 printf("Error cannot request tx18d42vm spi gpios\n");
65 ret = -EBUSY;
66 goto out;
67 }
68
69 for (i = 0; i < ARRAY_SIZE(init_data); i++)
70 lcd_panel_spi_write(cs, clk, mosi, init_data[i], 16);
71
72 mdelay(50); /* All the tx18d42vm drivers have a delay here ? */
73
74 lcd_panel_spi_write(cs, clk, mosi, 0x00ad, 16); /* display on */
75
76 out:
77 gpio_free(mosi);
78 gpio_free(clk);
79 gpio_free(cs);
80
81 return ret;
82 }
83