trogdor: Add backlight support for sn65dsi86bridge for Homestar
Add backlight support in sn65dsi86bridge through the AUX channel using
eDP DPCD registers, which is needed on the GOOGLE_HOMESTAR board.
Change-Id: Ie700080f1feabe2d3397c38088a64cff27bfbe55
Signed-off-by: Vinod Polimera <vpolimer@codeaurora.org>
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/52663
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/drivers/ti/sn65dsi86bridge/sn65dsi86bridge.c b/src/drivers/ti/sn65dsi86bridge/sn65dsi86bridge.c
index 1cbf6fd..2ba0977 100644
--- a/src/drivers/ti/sn65dsi86bridge/sn65dsi86bridge.c
+++ b/src/drivers/ti/sn65dsi86bridge/sn65dsi86bridge.c
@@ -31,6 +31,14 @@
#define DP_MAX_SUPPORTED_RATES 8 /* 16-bit little-endian */
#define DP_LANE_COUNT_MASK 0xf
+/* Backlight configuration */
+#define DP_BACKLIGHT_MODE_SET 0x721
+#define DP_BACKLIGHT_CONTROL_MODE_MASK 0x3
+#define DP_BACKLIGHT_CONTROL_MODE_DPCD 0x2
+#define DP_DISPLAY_CONTROL_REGISTER 0x720
+#define DP_BACKLIGHT_ENABLE 0x1
+#define DP_BACKLIGHT_BRIGHTNESS_MSB 0x722
+
/* link configuration */
#define DP_LINK_BW_SET 0x100
#define DP_LINK_BW_1_62 0x06
@@ -497,6 +505,20 @@
printk(BIOS_ERR, "ERROR: Link training failed 10 times\n");
}
+void sn65dsi86_backlight_enable(uint8_t bus, uint8_t chip)
+{
+ uint8_t val = DP_BACKLIGHT_CONTROL_MODE_DPCD;
+ sn65dsi86_bridge_aux_request(bus, chip, DP_BACKLIGHT_MODE_SET, 1, DPCD_WRITE, &val);
+
+ val = 0xff;
+ sn65dsi86_bridge_aux_request(bus, chip, DP_BACKLIGHT_BRIGHTNESS_MSB, 1,
+ DPCD_WRITE, &val);
+
+ val = DP_BACKLIGHT_ENABLE;
+ sn65dsi86_bridge_aux_request(bus, chip, DP_DISPLAY_CONTROL_REGISTER, 1,
+ DPCD_WRITE, &val);
+}
+
static void sn65dsi86_bridge_assr_config(uint8_t bus, uint8_t chip, int enable)
{
if (enable)