drm/bridge: add Silicon Image SiI9234 driver

SiI9234 transmitter converts eTMDS/HDMI signal to MHL 1.0.
It is controlled via I2C bus. Its interaction with other
devices in video pipeline is performed mainly on HW level.
The only interaction it does on device driver level is
filtering-out unsupported video modes, it exposes drm_bridge
interface to perform this operation.

This patch is based on the code refactored by Tomasz Stanislawski
<t.stanislaws@samsung.com>, which was initially developed by:
Adam Hampson <ahampson@sta.samsung.com>
Erik Gilling <konkers@android.com>
Shankar Bandal <shankar.b@samsung.com>
Dharam Kumar <dharam.kr@samsung.com>
Signed-off-by: Maciej Purski <m.purski@samsung.com>
Acked-by: Rob Herring <robh@kernel.org> [for dt bindings]
Reviewed-by: Andrzej Hajda <a.hajda@samsung.com>
Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1507212431-5801-2-git-send-email-m.purski@samsung.com

Documentation/devicetree/bindings/display/bridge/sii9234.txt

+Silicon Image SiI9234 HDMI/MHL bridge bindings
+
+Required properties:
+	- compatible : "sil,sii9234".
+	- reg : I2C address for TPI interface, use 0x39
+	- avcc33-supply : MHL/USB Switch Supply Voltage (3.3V)
+	- iovcc18-supply : I/O Supply Voltage (1.8V)
+	- avcc12-supply : TMDS Analog Supply Voltage (1.2V)
+	- cvcc12-supply : Digital Core Supply Voltage (1.2V)
+	- interrupts, interrupt-parent: interrupt specifier of INT pin
+	- reset-gpios: gpio specifier of RESET pin (active low)
+	- video interfaces: Device node can contain two video interface port
+			    nodes for HDMI encoder and connector according to [1].
+			    - port@0 - MHL to HDMI
+			    - port@1 - MHL to connector
+
+[1]: Documentation/devicetree/bindings/media/video-interfaces.txt
+
+
+Example:
+	sii9234@39 {
+		compatible = "sil,sii9234";
+		reg = <0x39>;
+		avcc33-supply = <&vcc33mhl>;
+		iovcc18-supply = <&vcc18mhl>;
+		avcc12-supply = <&vsil12>;
+		cvcc12-supply = <&vsil12>;
+		reset-gpios = <&gpf3 4 GPIO_ACTIVE_LOW>;
+		interrupt-parent = <&gpf3>;
+		interrupts = <5 IRQ_TYPE_LEVEL_HIGH>;
+
+		ports {
+			#address-cells = <1>;
+			#size-cells = <0>;
+
+			port@0 {
+				reg = <0>;
+				mhl_to_hdmi: endpoint {
+					remote-endpoint = <&hdmi_to_mhl>;
+				};
+			};
+			port@1 {
+				reg = <1>;
+				mhl_to_connector: endpoint {
+					remote-endpoint = <&connector_to_mhl>;
+				};
+			};
+		};
+	};

drivers/gpu/drm/bridge/Kconfig

@@ -84,6 +84,14 @@ config DRM_SII902X
 	---help---
 	  Silicon Image sii902x bridge chip driver.
 
+config DRM_SII9234
+	tristate "Silicon Image SII9234 HDMI/MHL bridge"
+	depends on OF
+	---help---
+	  Say Y here if you want support for the MHL interface.
+	  It is an I2C driver, that detects connection of MHL bridge
+	  and starts encapsulation of HDMI signal.
+
 config DRM_TOSHIBA_TC358767
 	tristate "Toshiba TC358767 eDP bridge"
 	depends on OF

drivers/gpu/drm/bridge/Makefile

@@ -6,6 +6,7 @@ obj-$(CONFIG_DRM_NXP_PTN3460) += nxp-ptn3460.o
 obj-$(CONFIG_DRM_PARADE_PS8622) += parade-ps8622.o
 obj-$(CONFIG_DRM_SIL_SII8620) += sil-sii8620.o
 obj-$(CONFIG_DRM_SII902X) += sii902x.o
+obj-$(CONFIG_DRM_SII9234) += sii9234.o
 obj-$(CONFIG_DRM_TOSHIBA_TC358767) += tc358767.o
 obj-$(CONFIG_DRM_ANALOGIX_DP) += analogix/
 obj-$(CONFIG_DRM_I2C_ADV7511) += adv7511/