hitachi_tx18d42vm_lcd.c
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// SPDX-License-Identifier: GPL-2.0+
/*
* Hitachi tx18d42vm LVDS LCD panel driver
*
* (C) Copyright 2015 Hans de Goede <hdegoede@redhat.com>
*/
#include <common.h>
#include <malloc.h>
#include <asm/gpio.h>
#include <errno.h>
/*
* Very simple write only SPI support, this does not use the generic SPI infra
* because that assumes R/W SPI, requiring a MISO pin. Also the necessary glue
* code alone would be larger then this minimal version.
*/
static void lcd_panel_spi_write(int cs, int clk, int mosi,
unsigned int data, int bits)
{
int i, offset;
gpio_direction_output(cs, 0);
for (i = 0; i < bits; i++) {
gpio_direction_output(clk, 0);
offset = (bits - 1) - i;
gpio_direction_output(mosi, (data >> offset) & 1);
udelay(2);
gpio_direction_output(clk, 1);
udelay(2);
}
gpio_direction_output(cs, 1);
udelay(2);
}
int hitachi_tx18d42vm_init(void)
{
const u16 init_data[] = {
0x0029, /* reset */
0x0025, /* standby */
0x0840, /* enable normally black */
0x0430, /* enable FRC/dither */
0x385f, /* enter test mode(1) */
0x3ca4, /* enter test mode(2) */
0x3409, /* enable SDRRS, enlarge OE width */
0x4041, /* adopt 2 line / 1 dot */
};
int i, cs, clk, mosi, ret = 0;
cs = name_to_gpio(CONFIG_VIDEO_LCD_SPI_CS);
clk = name_to_gpio(CONFIG_VIDEO_LCD_SPI_SCLK);
mosi = name_to_gpio(CONFIG_VIDEO_LCD_SPI_MOSI);
if (cs == -1 || clk == -1 || mosi == 1) {
printf("Error tx18d42vm spi gpio config is invalid\n");
return -EINVAL;
}
if (gpio_request(cs, "tx18d42vm-spi-cs") != 0 ||
gpio_request(clk, "tx18d42vm-spi-clk") != 0 ||
gpio_request(mosi, "tx18d42vm-spi-mosi") != 0) {
printf("Error cannot request tx18d42vm spi gpios\n");
ret = -EBUSY;
goto out;
}
for (i = 0; i < ARRAY_SIZE(init_data); i++)
lcd_panel_spi_write(cs, clk, mosi, init_data[i], 16);
mdelay(50); /* All the tx18d42vm drivers have a delay here ? */
lcd_panel_spi_write(cs, clk, mosi, 0x00ad, 16); /* display on */
out:
gpio_free(mosi);
gpio_free(clk);
gpio_free(cs);
return ret;
}