drm/panel: Add Sony Tulip Truly NT35521 driver

It adds a DRM panel driver for Sony Tulip Truly NT35521 5.24" 1280x720
DSI panel, which can be found on Sony Xperia M4 Aqua phone.  The panel
backlight is managed through DSI link.

The driver is built using linux-mdss-dsi-panel-driver-generator[1], and
additionally modeling the 5V control GPIOs with regulators and adding
Backlight GPIO support.

[1] https://github.com/msm8916-mainline/linux-mdss-dsi-panel-driver-generatorSigned-off-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20210809051008.6172-3-shawn.guo@linaro.org

drivers/gpu/drm/panel/Kconfig

@@ -610,6 +610,16 @@ config DRM_PANEL_SONY_ACX565AKM
 	  Say Y here if you want to enable support for the Sony ACX565AKM
 	  800x600 3.5" panel (found on the Nokia N900).
 
+config DRM_PANEL_SONY_TULIP_TRULY_NT35521
+	tristate "Sony Tulip Truly NT35521 panel"
+	depends on GPIOLIB && OF
+	depends on DRM_MIPI_DSI
+	depends on BACKLIGHT_CLASS_DEVICE
+	help
+	  Say Y here if you want to enable support for the Sony Tulip
+	  NT35521 1280x720 video mode panel as found on Sony Xperia M4
+	  Aqua phone.
+
 config DRM_PANEL_TDO_TL070WSH30
 	tristate "TDO TL070WSH30 DSI panel"
 	depends on OF

drivers/gpu/drm/panel/Makefile

@@ -62,6 +62,7 @@ obj-$(CONFIG_DRM_PANEL_SITRONIX_ST7703) += panel-sitronix-st7703.o
 obj-$(CONFIG_DRM_PANEL_SITRONIX_ST7789V) += panel-sitronix-st7789v.o
 obj-$(CONFIG_DRM_PANEL_SONY_ACX424AKP) += panel-sony-acx424akp.o
 obj-$(CONFIG_DRM_PANEL_SONY_ACX565AKM) += panel-sony-acx565akm.o
+obj-$(CONFIG_DRM_PANEL_SONY_TULIP_TRULY_NT35521) += panel-sony-tulip-truly-nt35521.o
 obj-$(CONFIG_DRM_PANEL_TDO_TL070WSH30) += panel-tdo-tl070wsh30.o
 obj-$(CONFIG_DRM_PANEL_TPO_TD028TTEC1) += panel-tpo-td028ttec1.o
 obj-$(CONFIG_DRM_PANEL_TPO_TD043MTEA1) += panel-tpo-td043mtea1.o