LCD 使用¶
简介¶
Face-RK3399开发板支持MIPI屏幕，接口对应板子上的位置如下图：
MIPI屏¶
客户根据需要在自行添加mipi硬件接口之后，配置MIPI屏的 Timing dts文件，在kernel/arch/arm64/boot/dts/rockchip/rk3399-firefly-face-mipi8.dts中可以看到以下语句：
display-timings {
native-mode = <&timing0>;
timing0: timing0 {
clock-frequency = <67000000>;//<80000000>;
hactive = <800>;//<768>;
vactive = <1280>;
hsync-len = <20>; //20, 50
hback-porch = <20>; //50, 56
hfront-porch = <32>;//50, 30
vsync-len = <4>;
vback-porch = <4>;
vfront-porch = <8>;
hsync-active = <0>;
vsync-active = <0>;
de-active = <0>;
pixelclk-active = <0>;
};
};
};
Kernel 在kernel/drivers/gpu/drm/panel/panel-simple.c中可以看到在初始化函数panel_simple_probe中初始化了获取时序的函数。
static int panel_simple_probe(struct device *dev, const struct panel_desc *desc){
···
panel->base.funcs = &panel_simple_funcs;
···
}
该函数的在kernel/drivers/gpu/drm/panel/panel-simple.c中也有定义：
static int panel_simple_get_timings(struct drm_panel *panel,unsigned int num_timings,struct display_timing *timings)
{
struct panel_simple *p = to_panel_simple(panel);
unsigned int i;
if (!p->desc)
return 0;
if (p->desc->num_timings < num_timings)
num_timings = p->desc->num_timings;
if (timings)
for (i = 0; i < num_timings; i++)
timings[i] = p->desc->timings[i];
return p->desc->num_timings;
}
mipi屏上完电后需要发送初始化指令才能使之工作，可以在kernel/arch/arm64/boot/dts/rockchip/firefly-face-mipi8.dts中可以看到mipi的初始化指令列表：
&mipi_dsi {
status = "okay";
...
panel-init-sequence = [
05 20 01 29
05 96 01 11
...
];
panel-exit-sequence = [
05 05 01 28
05 78 01 10
];
...
};
命令格式以及说明可参考以下附件： Rockchip DRM Panel Porting Guide.pdf
发送指令可以看到在kernel/drivers/gpu/drm/panel/panel-simple.c文件中的操作：
static int panel_simple_enable(struct drm_panel *panel)
{
struct panel_simple *p = to_panel_simple(panel);
int err;
if (p->enabled)
return 0;
DBG("enter\n");
if (p->on_cmds) {
err = panel_simple_dsi_send_cmds(p, p->on_cmds);
if (err)
dev_err(p->dev, "failed to send on cmds\n");
}
if (p->desc && p->desc->delay.enable) {
DBG("p->desc->delay.enable=%d\n", p->desc->delay.enable);
msleep(p->desc->delay.enable);
}
if (p->backlight) {
DBG("open backlight\n");
p->backlight->props.power = FB_BLANK_UNBLANK;
backlight_update_status(p->backlight);
}
p->enabled = true;
return 0;
}
U-boot 发送指令可以看到在u-boot/drivers/video/rockchip-dw-mipi-dsi.c文件中的操作：
static int rockchip_dw_mipi_dsi_enable(struct display_state *state)
{
struct connector_state *conn_state = &state->conn_state;
struct crtc_state *crtc_state = &state->crtc_state;
const struct rockchip_connector *connector = conn_state->connector;
const struct dw_mipi_dsi_plat_data *pdata = connector->data;
struct dw_mipi_dsi *dsi = conn_state->private;
u32 val;
DBG("enter\n");
dw_mipi_dsi_set_mode(dsi, DW_MIPI_DSI_VID_MODE);
dsi_write(dsi, DSI_MODE_CFG, ENABLE_CMD_MODE);
dw_mipi_dsi_set_mode(dsi, DW_MIPI_DSI_VID_MODE);
if (!pdata->has_vop_sel)
return 0;
if (pdata->grf_switch_reg) {
if (crtc_state->crtc_id)
val = pdata->dsi0_en_bit | (pdata->dsi0_en_bit << 16);
else
val = pdata->dsi0_en_bit << 16;
writel(val, RKIO_GRF_PHYS + pdata->grf_switch_reg);
}
debug("vop %s output to dsi0\n", (crtc_state->crtc_id) ? "LIT" : "BIG");
//rockchip_dw_mipi_dsi_read_allregs(dsi);
return 0;
}
EDP屏¶
在V2 版本硬件中，Face-rk3399 支持EDP屏幕显示输出。具体接口参考《接口定义》章节部分图片。
客户根据需要在自行添加EDP硬件接口之后，配置EDP屏的 Timing dts文件，在kernel/arch/arm64/boot/dts/rockchip/rk3399-firefly-face-edp15.dts中可以看到以下语句：
display-timings {
native-mode = <&timing0>;
timing0: timing0 {
clock-frequency = <140000000>;
hactive = <1920>;
vactive = <1080>;
hfront-porch = <100>;
hsync-len = <40>;
hback-porch = <40>;
vfront-porch = <10>;
vsync-len = <10>;
vback-porch = <10>;
hsync-active = <0>;
vsync-active = <0>;
de-active = <0>;
pixelclk-active = <0>;
};
};
这里定义了LCD的电源控制引脚：
lcd_en:gpios = <&gpio3 26 GPIO_ACTIVE_HIGH>;