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A new node into struct display_info_t const displays[] must to be added.
Starting from the above structure (data timings structure), edit the sub-structure "mode" by considering the following fields:
Field | Description |
|---|---|
name | name of the resolution, to use at U-Boot level |
refresh | refrash rate of the panel (pixecl clock / [ ( tot horiz. pixel) * (tot vert. pixel) ] |
xres | horizontal active area |
yres | vertical active area |
pixclock | pixel clock in pico seconds |
left_margin | horizontal back porch |
right_margin | horizontal fromt porch |
upper_margin | vertical back porch |
lower_margin | vertical fromt porch |
hsync_len | horizontal SYNC |
vsync_len | vertical SYNC |
| Code Block |
|---|
}, {
.bus = -1,
.addr = -1,
.pixfmt = IPU_PIX_FMT_RGB24,
.detect = NULL,
.enable = enable_lvds,
.mode = {
// Rif. Panel 1024x768 Panel UMSH-8596MD-15T
.name = "LDB-1280P60",
.refresh = 60,
.xres = 1280,
.yres = 800,
.pixclock = 15128,
.left_margin = 220,
.right_margin = 40,
.upper_margin = 21,
.lower_margin = 7,
.hsync_len = 60,
.vsync_len = 10,
.sync = 0,
.vmode = FB_VMODE_NONINTERLACED
}
}, {
.bus = -1,
.addr = -1,
.pixfmt = IPU_PIX_FMT_RGB24,
.detect = NULL,
.enable = enable_lvds,
.mode = {
// new data structure
.name = "NEW CUSTOM RESOLUTION",
.refresh = <custom refresh>,
.xres = <custom horiz. resolution>,
.yres = <custom vert. resolution>,
.pixclock = <pixel clock in us>,
.left_margin = <horiz. back porch>,
.right_margin = <horiz. front porch>,
.upper_margin = <vert. back porch>,
.lower_margin = <vert. front porch>,
.hsync_len = <horiz. SYNC lenght>,
.vsync_len = <vert. SYNC lenght>,
.sync = 0,
.vmode = FB_VMODE_NONINTERLACED
} |
...
DCCS can be connected to HDMI, DP or MIPI-DSI and supports up to 4K resolution;
eLCDIF can be connected only to MIPI-DSI and supports up to 1080p resolution.
Adding Custom LVDS / eDP panel support in panel-simple.c for i.MX8
The panel is configured by the following nodes located in the board device tree, for example arch/arm64/boot/dts/seco/seco-imx8mm-c61.dts:
...
| Code Block |
|---|
linux-seco/drivers/gpu/drm/panel/panel-simple.c |
Example: Configure the custom display timing for AUO Panel model p215hca
In the Seco BSP's the references panels are configured and tested with 10000 on/off cycle. Below the panel structure from drivers/gpu/drm/panel/panel-simple.c for LVDS 1920x1080 from Seco BSP9:
...
| Note |
|---|
The above configurations can be useless in some cases and prevent the panel from turning on. |
SECO preconfigured Panels
Below are some pre-built Device Tree Overlay files for i.MX8-based boards.
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