cmd: Allow to turn on backlight on demand

cmd/Makefile

@@ -17,6 +17,7 @@ obj-$(CONFIG_CMD_AB_SELECT) += ab_select.o
 obj-$(CONFIG_CMD_ADC) += adc.o
 obj-$(CONFIG_CMD_ARMFLASH) += armflash.o
 obj-$(CONFIG_HAVE_BLOCK_DEVICE) += blk_common.o
+obj-$(CONFIG_DM_VIDEO) += backlight.o
 obj-$(CONFIG_CMD_SOURCE) += source.o
 obj-$(CONFIG_CMD_BCB) += bcb.o
 obj-$(CONFIG_CMD_BDI) += bdinfo.o

cmd/backlight.c

@@ -0,0 +1,20 @@
+// SPDX-License-Identifier: GPL-2.0+
+#include <common.h>
+#include <command.h>
+#include <dm.h>
+#include <backlight.h>
+
+static int do_backlight(cmd_tbl_t *cmdtp, int flag, int argc,
+			char *const argv[])
+{
+	struct udevice *backlight;
+	int ret;
+
+	ret = uclass_get_device(UCLASS_PANEL_BACKLIGHT, 0, &backlight);
+	if (!ret)
+		backlight_enable(backlight);
+
+	return CMD_RET_SUCCESS;
+}
+
+U_BOOT_CMD(backlight_on, 1, 1, do_backlight, "Backlight", " - enable backlightpanel devices");

drivers/video/sunxi/sunxi_lcd.c

@@ -67,11 +67,11 @@ static int sunxi_lcd_enable(struct udevice *dev, int bpp,
 	lcdc_tcon0_mode_set(lcdc, edid, clk_div, false,
 			    priv->panel_bpp, CONFIG_VIDEO_LCD_DCLK_PHASE);
 	lcdc_enable(lcdc, priv->panel_bpp);
-
+/*
 	ret = uclass_get_device(UCLASS_PANEL_BACKLIGHT, 0, &backlight);
 	if (!ret)
 		backlight_enable(backlight);
-
+*/
 	return 0;
 }