MIPI DSI Use¶
Kernel configuration¶
Add the following configuration in arch/arm/configs/firefly_defconfig：
CONFIG_LCD_MIPI=y
CONFIG_MIPI_DSI=y
CONFIG_RK32_MIPI_DSI=y
Driver configuration¶
Add a new dts file¶
Add a new dts file in the path “arch/arm/boot/dts/”, such as lcd-xxx-mipi.dtsi
Include the dts file and close the tve enable¶
Include the dts file you add in first step in path “arch/arm/boot/dts/aio-3128c.dts”. If there have included other display’s DTS files, please make them as annotation .If you want to use mipi lcd, you need to close tve enable：
&tve {
status = "disabled";
test_mode = <0>;
};
Add backlight configuration¶
Add backlight configuration in lcd-xxx-mipi.dtsi, for example:
backlight {
compatible = "pwm-backlight";
pwms = <&pwm0 0 25000>;
rockchip,pwm_id= <1>;
/* | dark(255-221) | light scale(220-0) | , scale_div=255*/
brightness-levels = </*255 254 253 252 251 250 249 248 247 246 245 244 243 242 241 240 239 238 237 236 235 234 233 232 231 230 229 228 227
266 225 224 223 222 221 */220 219 218 217 216 215 214 213 212 211 210 209 208 207 206 205 204 203 202 201 200 199 198 197 196 195 194 193 192 191 190 189
188 187 186 185 184 183 182 181 180 179 178 177 176 175 174 173 172 171 170 169 168 167 166 165 164 163 162 161 160 159 158 157 156 155 154 153 152 151
150 149 148 147 146 145 144 143 142 141 140 139 138 137 136 135 134 133 132 131 130 129 128 127 126 125 124 123 122 121 120 119 118 117 116 115 114 113
112 111 110 109 108 107 106 105 104 103 102 101 100 99 98 97 96 95 94 93 92 91 90 89 88 87 86 85 84 83 82 81 80 79 78 77 76 75 74 73 72 71 70 69 68 67 66
65 64 63 62 61 60 59 58 57 56 55 54 53 52 51 50 49 48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15
14 13 12 11 10 9 8 7 6 5 4 3 2 1 0>;
default-brightness-level = <180>;
enable-gpios = <&gpio1 GPIO_A7 GPIO_ACTIVE_HIGH>;
};
Pwms: the attribute of PWM. The AIO-3128C use pwm1. 25000 is the frequency of PWM.
brightness-level: array for back light, the max value is 255. The configuration of dark and light area.
default-brightness-level: default brightness, the range of this value is 0~255.
enable-gpios: the enable pin of back light.
See the documentations in the follow path for more information: Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt
Configure information of MIPI¶
Add the configure information of MIPI in lcd-xxx-mipi.dtsi, for example:
disp_mipi_init: mipi_dsi_init{
compatible = "rockchip,mipi_dsi_init";
rockchip,screen_init = <1>;
rockchip,dsi_lane = <4>;
rockchip,dsi_hs_clk = <500>;
rockchip,mipi_dsi_num = <1>;
};
rockchip,screen_init: the value of 0 means without special instruction while initial. The value of 1 means need the special instruction to initial the LCD display.
rockchip,dsi_lane: the number of lane.
rockchip,dsi_hs_clk: the value of hsclk.
rockchip,mipi_dsi_num：the number of DSI interface, single channel is 1, dual channel is 2.（fireprime MIPI only supports single channel screen）.
See the documentation of the follow path for more information: Documentation/devicetree/bindings/video/rockchip_mipidsi_lcd.txt
LCD pins configuration¶
Add the LCD pins configuration in lcd-xxx-mipi.dtsi, for example:
disp_mipi_power_ctr: mipi_power_ctr {
compatible = "rockchip,mipi_power_ctr";
mipi_lcd_rst:mipi_lcd_rst{
compatible = "rockchip,lcd_rst";
rockchip,gpios = <&gpio2 GPIO_B0 GPIO_ACTIVE_LOW>;
rockchip,delay = <10>;
};
/*
mipi_lcd_en:mipi_lcd_en {
compatible = "rockchip,lcd_en";
rockchip,gpios = <&gpio0 GPIO_C1 GPIO_ACTIVE_HIGH>;
rockchip,delay = <10>;
};*/
};
There are power enable pin “mipi_lcd_en”, chip select pin “mipi_lcd_cs”, reset pin “mipi_lcd_rst”. You can modify those configuration according to the LCD.
The configuration of initial instructions¶
Add the configuration of initial instructions in lcd-xxx-mipi.dtsi, for example:
disp_mipi_init_cmds: screen-on-cmds {
rockchip,cmd_debug = <0>;
compatible = "rockchip,screen-on-cmds";
rockchip,on-cmds1 {
compatible = "rockchip,on-cmds";
rockchip,cmd_type = <LPDT>;
rockchip,dsi_id = <0>;
rockchip,cmd = <0x05 0x29>;
rockchip,cmd_delay = <0>;
};
rockchip,on-cmds2 {
compatible = "rockchip,on-cmds";
rockchip,cmd_type = <LPDT>;
rockchip,dsi_id = <0>;
rockchip,cmd = <0x05 0x11>;
rockchip,cmd_delay = <200>;
};
};
It will need the special instructions to initial the When the value of “rockchip,screen_init” is set to 1.
rockchip,cmd_debug: Set this value to 1 and you will get the debug information from the debug serial.
rockchip,on-cmdsXX: the information of each instruction.
rockchip,cmd_type：the mode for data transfer. PDT mode or HSDT mode.
rockchip,dsi_id：The DSI interface for instructions transfer. If this value is set to 0 means using the DSI0(it’s the left side of the display while dual lane MIPI display ) for instruction transfer.If this value is set to1 means using the DSI1(it’s the right side of the display while dual lane MIPI display ) for instruction transfer. This value is set to 2 means using both the DSI0 and DSI1 for instruction transfer.
rockchip,cmd：the sequence of the instructions. The first Byte is the DSI data type, the second Byte is the RGE. The rest are the instructions.
rockchip,cmd_delay：the delay after sending instructions. The unit is ms.
The configuration of display sequence¶
Add the configuration of display sequence in lcd-xxx-mipi.dtsi, for example:
disp_timings: display-timings {
native-mode = <&timing0>;
compatible = "rockchip,display-timings";
timing0: timing0 {
screen-type = <SCREEN_MIPI>;
lvds-format = <LVDS_8BIT_2>;
out-face = <OUT_P666>;
color-mode = <COLOR_RGB>;
clock-frequency = <67000000>;
hactive = <768>;
vactive = <1024>;
hsync-len = <64>;
hback-porch = <56>;
hfront-porch = <60>;
vsync-len = <14>;
vback-porch = <30>;
vfront-porch = <36>;
hsync-active = <0>;
vsync-active = <0>;
de-active = <0>;
pixelclk-active = <1>;
swap-rb = <0>;
swap-rg = <0>;
swap-gb = <0>;
};
};
Configure the time sequence in disp_timings node.
screen-type: Display type. fireprime MIPI only supports single channel screen,so the display type is SCREEN_MIPI.
lvds-format: Independent options.
out-face: color configuration, it can be OUT-P888(24 bits), OUT_P666(18 bits)or OUT_P565(16 bits)
clock-frequency: clock of the LCD, measure by Hz.
As to other timing’s attribute, you can take a look at this picture.
Dsihost configuration¶
Using single MIPI, enable the dsihost0, for example:
&dsihost0 {
status = "okay";
};