Foreword
This chapter introduces how to add the LCD screen GC9306 driver.
Circuit diagram
dts
build\boards\cv180x\cv1800b_milkv_duo_sd\dts_riscv\cv1800b_milkv_duo_sd.dts
& amp;spi2 {<!-- -->
status = "okay";
/delete-node/ spidev@0;
gc9306: gc9306@0{<!-- -->
compatible = "sitronix,gc9306";
reg = <0>;
status = "okay";
spi-max-frequency = <48000000>;
spi-cpol;
spi-cpha;
rotate = <90>;
fps = <30>;
rgb;
buswidth = <8>;
//dc-gpios = < & amp;port 21 GPIO_ACTIVE_HIGH>; //DC
dc-gpios = < & amp;porta 23 GPIO_ACTIVE_HIGH>; //DC
reset-gpios = < & amp;porta 24 GPIO_ACTIVE_HIGH>; //RES
led-gpios = < & amp;porta 14 GPIO_ACTIVE_HIGH>; //BL
debug = <0x1>;
};
};
makefile
linux_5.10\drivers\staging\fbtft\Makefile
obj-$(CONFIG_FB_TFT_GC9306) + = fb_gc9306.o
config
linux_5.10\drivers\staging\fbtft\Kconfig
config FB_TFT_GC9306 tristate "FB driver for the GC9306 LCD Controller" depends on FB_TFT help Generic Framebuffer support for GC9306
decofig
build\boards\cv180x\cv1800b_milkv_duo_sd\linux\cvitek_cv1800b_milkv_duo_sd_defconfig
CONFIG_FB_TFT_GC9306=y
Driver
linux_5.10\drivers\staging\fbtft\fb_gc9306.c
// SPDX-License-Identifier: GPL-2.0 +
/*
* FB driver for the GC9306 LCD Controller
*
* Copyright (C) 2015 Dennis Menschel
*/
#include <linux/bitops.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <video/mipi_display.h>
#include "fbtft.h"
#define DRVNAME "fb_gc9306"
#define GC9306_IPS_GAMMA \
"02 00 00 1b 1f 0b\
" \
"01 03 00 28 2b 0e\
" \
"0b 08 3b 04 03 4c\
" \
"0e 07 46 04 05 51\
" \
"08 15 15 1f 22 0F\
" \
"0b 13 11 1f 21 0F"
/**
* init_display() - initialize the display controller
*
* @par: FBTFT parameter object
*
* Most of the commands in this init function set their parameters to the
* same default values which are already in place after the display has been
* powered up. (The main exception to this rule is the pixel format which
* would default to 18 instead of 16 bit per pixel.)
* Nonetheless, this sequence can be used as a template for concrete
* displays which usually need some adjustments.
*
* Return: 0 on success, < 0 if error occurred.
*/
static int init_display(struct fbtft_par *par)
{<!-- -->
par->fbtftops.reset(par);//Hard reset
mdelay(50);
//display control setting
write_reg(par, 0xfe);
write_reg(par, 0xef);
write_reg(par, MIPI_DCS_SET_ADDRESS_MODE, 0x48);//MX, MY, RGB mode refresh direction 48 vertical screen
write_reg(par, MIPI_DCS_SET_PIXEL_FORMAT, MIPI_DCS_PIXEL_FMT_16BIT);//65k mode
write_reg(par, 0xad,0x33);
write_reg(par, 0xaf,0x55);
write_reg(par, 0xae,0x2b);
//GC9306 Power Sequence
write_reg(par, 0xa4,0x44,0x44);
write_reg(par, 0xa5,0x42,0x42);
write_reg(par, 0xaa,0x88,0x88);
write_reg(par, 0xae,0x2b);
write_reg(par, 0xe8,0x11,0x0b);
write_reg(par, 0xe3,0x01,0x10);
write_reg(par, 0xff,0x61);
write_reg(par, 0xac,0x00);
write_reg(par, 0xaf,0x67);
write_reg(par, 0xa6,0x2a,0x2a);
write_reg(par, 0xa7,0x2b,0x2b);
write_reg(par, 0xa8,0x18,0x18);
write_reg(par, 0xa9,0x2a,0x2a);
//display window 240X320 matching mode
write_reg(par, 0x2a,0x00,0x00,0x00,0xef); //MIPI_DCS_SET_COLUMN_ADDRESS - 240
write_reg(par, 0x2b,0x00,0x00,0x01,0x3f); //MIPI_DCS_SET_PAGE_ADDRESS - 320
write_reg(par, 0x2c); //MIPI_DCS_WRITE_MEMORY_START
//GC9306 Gamma Sequence
write_reg(par, 0xF0,0x02,0x00,0x00,0x1b,0x1f,0x0b);
write_reg(par, 0xF1,0x01,0x03,0x00,0x28,0x2b,0x0e);
write_reg(par, 0xF2,0x0b,0x08,0x3b,0x04,0x03,0x4c);
write_reg(par, 0xF3,0x0e,0x07,0x46,0x04,0x05,0x51);
write_reg(par, 0xF4,0x08,0x15,0x15,0x1f,0x22,0x0F);
write_reg(par, 0xF5,0x0b,0x13,0x11,0x1f,0x21,0x0F);
/* Sleep Out */
write_reg(par, 0x11); //MIPI_DCS_EXIT_SLEEP_MODE
mdelay(100);
write_reg(par, 0x2c); //MIPI_DCS_WRITE_MEMORY_START
//luat_lcd_clear(par, BLACK);
/* display on */
write_reg(par, 0x29); //MIPI_DCS_SET_DISPLAY_ON - 29
mdelay(100);
return 0;
}
/**
* set_var() - apply LCD properties like rotation and BGR mode
*
* @par: FBTFT parameter object
*
* Return: 0 on success, < 0 if error occurred.
*/
static int set_var(struct fbtft_par *par)
{<!-- -->
u8 madctl_par = 0;
if (par->bgr)
madctl_par =0x48;
switch (par->info->var.rotate) {<!-- -->
case 0:
madctl_par = 0x48;
break; //48
case 90:
madctl_par = 0xE8;
break;
case 180:
madctl_par =0x28;
break;
case 270:
madctl_par =0xF8;
break;
default:
return -EINVAL;
}
write_reg(par, MIPI_DCS_SET_ADDRESS_MODE, madctl_par);
return 0;
}
/**
* set_gamma() - set gamma curves
*
* @par: FBTFT parameter object
* @curves: gamma curves
*
* Before the gamma curves are applied, they are preprocessed with a bitmask
* to ensure syntactically correct input for the display controller.
* This implies that the curves input parameter might be changed by this
* function and that illegal gamma values are auto-corrected and not
* reported as errors.
*
* Return: 0 on success, < 0 if error occurred.
*/
static int set_gamma(struct fbtft_par *par, u32 *curves)
{<!-- -->
//GC9306 Gamma Sequence
write_reg(par, 0xF0,0x02,0x00,0x00,0x1b,0x1f,0x0b);
write_reg(par, 0xF1,0x01,0x03,0x00,0x28,0x2b,0x0e);
write_reg(par, 0xF2,0x0b,0x08,0x3b,0x04,0x03,0x4c);
write_reg(par, 0xF3,0x0e,0x07,0x46,0x04,0x05,0x51);
write_reg(par, 0xF4,0x08,0x15,0x15,0x1f,0x22,0x0F);
write_reg(par, 0xF5,0x0b,0x13,0x11,0x1f,0x21,0x0F);
return 0;
}
/**
* blank() - blank the display
*
* @par: FBTFT parameter object
* @on: whether to enable or disable blanking the display
*
* Return: 0 on success, < 0 if error occurred.
*/
static int blank(struct fbtft_par *par, bool on)
{<!-- -->
if (on)
write_reg(par, MIPI_DCS_SET_DISPLAY_OFF);
else
write_reg(par, MIPI_DCS_SET_DISPLAY_ON);
return 0;
}
static struct fbtft_display display = {<!-- -->
.regwidth = 8,
.width = 240,
.height = 320,
.gamma_num = 6,
.gamma_len = 6,
.gamma = GC9306_IPS_GAMMA,
.fbtftops = {<!-- -->
.init_display = init_display,
.set_var = set_var,
.set_gamma = set_gamma,
.blank = blank,
},
};
FBTFT_REGISTER_DRIVER(DRVNAME, "sitronix,gc9306", & amp;display);
MODULE_ALIAS("spi:" DRVNAME);
MODULE_ALIAS("platform:" DRVNAME);
MODULE_ALIAS("spi:gc9306");
MODULE_ALIAS("platform:gc9306");
MODULE_DESCRIPTION("FB driver for the GC9306 LCD Controller");
MODULE_AUTHOR("Dennis Menschel & amp; Youkai");
MODULE_LICENSE("GPL");
Test
