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 <malloc.h>
9#include <linux/delay.h>
10
11#include <asm/gpio.h>
12#include <sunxi_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 */
20static 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
38int 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 = sunxi_name_to_gpio(CONFIG_VIDEO_LCD_SPI_CS);
53	clk = sunxi_name_to_gpio(CONFIG_VIDEO_LCD_SPI_SCLK);
54	mosi = sunxi_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
76out:
77	gpio_free(mosi);
78	gpio_free(clk);
79	gpio_free(cs);
80
81	return ret;
82}
83