RK3288：linux系统中MIPI接口的5寸LCD显示屏的调试

RK3288的LCD调试，根据屏幕规格书对dts作相应的修改基本都可点亮,配置也较为简单

 

 

 

Platform : Rockchip 
Soc : RK3288 
System : linux（buidroot）

IC:NT35523

内核：4.4

 

 

先做一些准备工作，多看看LCD的手册

 

 

 

提炼出来关键信息是：
Hactive = 800 ，水平分辨率
Vactive = 2560 ，垂直分辨率
Lanes = 4 ，Mipi data 信号线通道数

 

 

硬件上，复位信号的时序要对：

 

 

 

 

主要参数的提取：

 

关键信息提炼出来：

4 data lines(厂家推荐值)：
Hactive = 800
HFP = 40
HBP = 20
Hsync = 20

Vactive = 1280
VFP = 20
VBP = 20
VSync = 10

clock-frequency = (h_active + hfp + hbp + h_sync) * (v_active + vfp + vbp + v_sync) * fps

厂商给参考值60Hz,

 fps= clk/ (800 + 40 + 20 +20) * (1280 + 20 + 20 + 10) = 60Hz

Pixel Clock Frequency（Pclk）= 70.22MHZ

这里我们详细说一下各个参数的含义，这个对我们后续调屏会非常有帮助。
另外根据以上的信息，我们还能计算出 Mipi Dsi Clock 。
DCLK = 100 + H_total×V_total × fps × 3 × 8 / lanes_nums
total 这里指的是 sync + front + back + active
比如 H_total = Hsync + HFP(hfront-proch) + HBP(hback-porch) + Hactive
fps 指的是帧率，一般我们按照 60 帧来计算
3 × 8 代表一个 RGB 为 3 个字节，每个字节 8 bit
lanes 代表 mipi data 通道数

所以对于我这个屏
DCLK
= 100Mbps + H_Total × V_Total x fps x 3 x 8 / lanes_nums
= 100 + ( 800 + 40 + 20 + 20 ) x ( 1280 + 20 + 20+ 10 ) x 60 帧 x 3 字节 x 8 bit / 4 lanes
= 100Mbps + 421Mbps = 521 Mbps

MIPI CLK Lane * 2 = MIPI DATA Lane

 

 

原理图，GPIO的配置：

 

 

 

 

 

现在附上设备树中dts文件LCD部分的代码：

+/*************add by lml start*********************/
+
+
+&dsi0 {
+    status = "okay";
+
+    panel@0 {
+        compatible = "simple-panel-dsi";
+        reg = <0>;
+        backlight = <&backlight>;
+ //       enable-gpios = <&gpio1 4 GPIO_ACTIVE_HIGH>;
+        reset-gpios  = <&gpio6 5 GPIO_ACTIVE_LOW>;
+
+        prepare-delay-ms = <120>;
+        reset-delay-ms = <120>;
+        init-delay-ms = <120>;
+        enable-delay-ms = <120>;
+        unprepare-delay-ms = <120>;
+        disable-delay-ms = <120>;
+
+        width-mm = <113>;
+        height-mm = <181>;
+
+        dsi,flags = <(MIPI_DSI_MODE_VIDEO | MIPI_DSI_MODE_VIDEO_BURST |
+                  MIPI_DSI_MODE_LPM | MIPI_DSI_MODE_EOT_PACKET)>;
+        dsi,format = ;
+        dsi,lanes = <4>;
+
+        panel-init-sequence = [
+        39 00 06 f0 55 aa 52 08 00
+	39 00 0a c0 00 00 00 00 00 00 00 00 02
+	15 00 02 c8 80
+	39 00 03 b1 e8 21
+	39 00 03 b5 05 00
+	39 00 03 bb 93 93
+	39 00 03 bc 0f 00
+	39 00 05 bd 11 30 10 10
+	39 00 06 f0 55 aa 52 08 01
+	15 00 02 ce 00
+	39 00 03 b7 00 48
+	15 00 02 ce 00
+	15 00 02 ca 03
+	39 00 03 b3 23 23
+	39 00 03 b4 23 23
+	39 00 03 c3 5a 5a
+	39 00 03 c4 5a 5a
+	39 00 03 c2 5a 5a
+	39 00 03 b9 44 44
+	39 00 03 ba 24 24
+	39 00 03 bc 50 00
+	39 00 03 bd 50 00
+	39 00 03 be 00 71
+	39 00 03 bf 00 a0
+	39 00 06 f0 55 aa 52 08 02
+	15 00 02 b0 40
+	39 00 11 d1 00 00 00 1b 00 40 00 5b 00 71 00 97 00 b5 00 e6
+	39 00 11 d2 01 0d 01 4b 01 7c 01 c8 02 03 02 05 02 3a 02 72
+	39 00 11 d3 02 95 02 c5 02 e7 03 15 03 32 03 57 03 71 03 95
+	39 00 05 d4 03 b0 03 b3
+	39 00 06 f0 55 aa 52 08 03
+	39 00 05 b0 00 00 00 00
+	39 00 05 b1 00 00 00 00
+	39 00 08 b2 00 00 0a 06 00 f0 5b
+	39 00 08 b3 00 00 09 06 00 f0 5b 
+	39 00 0b b6 f0 05 06 03 00 00 00 00 10 10
+	39 00 0b b7 f0 05 07 03 00 00 00 00 10 10
+	39 00 08 bc c5 03 00 08 00 f0 5b
+	39 00 03 c4 00 00
+	39 00 06 f0 55 aa 52 08 05
+	39 00 05 b0 33 04 00 01
+	39 00 03 b1 40 00
+	39 00 04 b2 03 02 22
+	39 00 05 b3 83 23 42 9a
+	39 00 05 b4 c5 35 77 53
+	39 00 08 b5 4c e5 31 33 33 a3 0a
+	39 00 07 b6 00 00 d5 31 77 53
+	39 00 06 b9 00 00 00 05 00
+	39 00 06 c0 35 33 33 50 05
+	39 00 05 c6 00 00 00 00
+	39 00 03 ce f0 1f
+	39 00 06 d2 00 25 02 00 00
+	39 00 03 e7 e8 ff
+	39 00 03 e8 ff ff
+	15 00 02 e9 00
+	15 00 02 ea aa
+	15 00 02 eb aa
+	15 00 02 ec aa
+	15 00 02 ee aa
+	39 00 06 f0 55 aa 52 08 06
+	39 00 06 b0 7d 4a 7d 7d 7d
+	39 00 06 b1 7d 7d 42 5d 7d
+	39 00 06 b2 7d 63 61 7d 7d
+	39 00 06 b3 5f 72 7d 7d 7d
+	39 00 03 b4 7d 7d
+	39 00 06 b5 7d 48 7d 7d 7d
+	39 00 06 b6 7d 7d 40 5c 7d
+	39 00 06 b7 7d 62 60 7d 7d
+	39 00 06 b8 5e 72 7d 7d 7d
+	39 00 03 b9 7d 7d	
+	15 00 02 35 00  
+	05 96 01 11	  
+	05 96 01 29
+	];
+
+        panel-exit-sequence = [
+            05 00 01 28
+            05 78 01 10
+        ];
+
+        display-timings {
+            native-mode = <&timing0>;
+
+            timing0: timing0 {
+                clock-frequency = <66000000>;
+                hactive = <1280>;
+                vactive = <800>;
+                hback-porch = <20>;
+                hsync-len = <10>;
+                hfront-porch = <40>;
+                vback-porch = <20>;
+                vfront-porch = <20>;
+                vsync-len = <10>;
+                hsync-active = <0>;
+                vsync-active = <0>;
+                de-active = <0>;
+                pixelclk-active = <0>;
+            };
+        };
+    };
+};
+
+
+&dsi0_in_vopl {
+    status = "disabled";
+};
+
+&dsi0_in_vopb {
+    status = "okay";
+};
+
+&route_dsi0 {
+    connect = <&vopb_out_dsi0>;
+    status = "okay";
+};
+
+/*************add by lml end*********************/

 

 

 

 

 

 

 

 

 

初始化代码解析（MIPI必须有初始化代码才能点亮，这个有原厂提供）：

     panel-init-sequence = [

              39 00 06 f0 55 aa 52 08 00

             ..................................................

            05 96 01 29
   ];

 

说明：前 3 个字节（16 进制），分别代表 Data Type，Delay，Payload Length。
从第四个字节开始的数据代表长度为 Length 的实际有效 Payload。

第一条命令的解析如下：

  39 00 06 f0 55 aa 52 08 00

Data Type：0x39 (DCS Long Write)
Delay：0x00 (0 ms)
Payload Length：0x06 (4 Bytes)
Payload：f0 55 aa 52 08 00

 

最后一条命令的解析如下：

05 96 01 29

Data Type：0x05 (DCS Short Write, no parameters)
Delay：0x96 (150 ms)
Payload Length：0x01 (1 Bytes)
Payload：0x29