前言

本章介绍如何添加LCD屏GC9306驱动。

电路图

dts

build\boards\cv180x\cv1800b_milkv_duo_sd\dts_riscv\cv1800b_milkv_duo_sd.dts

&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 = <&port 21 GPIO_ACTIVE_HIGH>;	//DCdc-gpios = <&porta 23 GPIO_ACTIVE_HIGH>;	//DCreset-gpios = <&porta 24 GPIO_ACTIVE_HIGH>; //RESled-gpios = <&porta 14 GPIO_ACTIVE_HIGH>; //BLdebug = <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_GC9306tristate "FB driver for the GC9306 LCD Controller"depends on FB_TFThelpGeneric Framebuffer support for GC9306

decofig

build\boards\cv180x\cv1800b_milkv_duo_sd\linux\cvitek_cv1800b_milkv_duo_sd_defconfig

CONFIG_FB_TFT_GC9306=y

驱动

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\n" \"01 03 00 28 2b 0e\n" \"0b 08 3b 04 03 4c\n" \"0e 07 46 04 05 51\n" \"08 15 15 1f 22 0F\n" \"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);//硬复位mdelay(50);//display control settingwrite_reg(par, 0xfe);write_reg(par, 0xef);write_reg(par, MIPI_DCS_SET_ADDRESS_MODE, 0x48);//MX, MY, RGB mode 刷新方向 48竖屏write_reg(par, MIPI_DCS_SET_PIXEL_FORMAT, MIPI_DCS_PIXEL_FMT_16BIT);//65k modewrite_reg(par, 0xad,0x33);write_reg(par, 0xaf,0x55);write_reg(par, 0xae,0x2b);//GC9306 Power Sequencewrite_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 匹配modewrite_reg(par, 0x2a,0x00,0x00,0x00,0xef);   //MIPI_DCS_SET_COLUMN_ADDRESS - 240write_reg(par, 0x2b,0x00,0x00,0x01,0x3f);   //MIPI_DCS_SET_PAGE_ADDRESS - 320write_reg(par, 0x2c);                       //MIPI_DCS_WRITE_MEMORY_START//GC9306 Gamma Sequencewrite_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_MODEmdelay(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 - 29mdelay(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; //48case 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 Sequencewrite_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);elsewrite_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", &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 & Youkai");
MODULE_LICENSE("GPL");

测试