Hi Andrzej,
On Wednesday, 30 May 2018 12:59:12 EEST Andrzej Hajda wrote:
On 28.05.2018 12:18, Laurent Pinchart wrote:
On Monday, 28 May 2018 12:47:11 EEST Maciej Purski wrote:
The patch adds bindings to Toshiba DSI/LVDS bridge TC358764. Bindings describe power supplies, reset gpio and video interfaces.
Signed-off-by: Andrzej Hajda a.hajda@samsung.com Signed-off-by: Maciej Purski m.purski@samsung.com
.../bindings/display/bridge/toshiba,tc358764.txt | 42 ++++++++++++++++ 1 file changed, 42 insertions(+) create mode 100644
Documentation/devicetree/bindings/display/bridge/toshiba,tc358764.txt
diff --git a/Documentation/devicetree/bindings/display/bridge/toshiba,tc358764.txt b/Documentation/devicetree/bindings/display/bridge/toshiba,tc358764.txt new file mode 100644 index 0000000..d09bdc2 --- /dev/null +++ b/Documentation/devicetree/bindings/display/bridge/toshiba,tc358764.txt @@ -0,0 +1,42 @@ +TC358764 MIPI-DSI to LVDS panel bridge
+Required properties:
- compatible: "toshiba,tc358764"
- reg: the virtual channel number of a DSI peripheral
- vddc-supply: core voltage supply
- vddio-supply: I/O voltage supply
- vddmipi-supply: MIPI voltage supply
- vddlvds133-supply: LVDS1 3.3V voltage supply
- vddlvds112-supply: LVDS1 1.2V voltage supply
That's a lot of power supplies. Could some of them be merged together ? See https://patchwork.freedesktop.org/patch/216058/ for an earlier discussion on the same subject.
Specs says about 3 supply voltage values:
- 1.2V - digital core, DSI-RX PHY
- 1.8-3.3V - digital I/O
- 3.3V - LVDS-TX PHY
So I guess it should be minimal number of supplies. Natural candidates:
- vddc-supply: core voltage supply, 1.2V
- vddio-supply: I/O voltage supply, 1.8V or 3.3V
- vddlvds-supply: LVDS1/2 voltage supply, 3.3V
I have changed name of the latest supply to be more consistent with other supplies, and changed 1.8-3.3 (which incorrectly suggest voltage range), to more precise voltage alternative.
This looks fine to me.
- reset-gpios: a GPIO spec for the reset pin
+The device node can contain zero to two 'port' child nodes, each with one +child +'endpoint' node, according to the bindings defined in [1]. +The following are properties specific to those nodes.
+port:
- reg: (required) can be 0 for DSI port or 1 for LVDS port;
This seems pretty vague to me. It could be read as meaning that ports are completely optional, and that the port number you list can be used, but that something else could be used to.
Let's make the port nodes mandatory. I propose the following.
Required nodes:
The TC358764 has DSI and LVDS ports whose connections are described using the OF graph bindings defined in Documentation/devicetree/bindings/graph.txt. The device node must contain one 'port' child node per DSI and LVDS port. The port nodes are numbered as follows.
Port Number
DSI Input 0 LVDS Output 1
Each port node must contain endpoint nodes describing the hardware connections.
Since the bridge is controlled via DSI bus, DSI input port is not necessary.
I don't agree with this. Regardless of how the bridge is controlled, I think we should always use ports to describe the data connections. Otherwise it would get more complicated for display controller drivers to use different types of bridges.
+[1]: Documentation/devicetree/bindings/media/video-interfaces.txt
+Example:
- bridge@0 {
reg = <0>;compatible = "toshiba,tc358764";vddc-supply = <&vcc_1v2_reg>;vddio-supply = <&vcc_1v8_reg>;vddmipi-supply = <&vcc_1v2_reg>;vddlvds133-supply = <&vcc_3v3_reg>;vddlvds112-supply = <&vcc_1v2_reg>;reset-gpios = <&gpd1 6 GPIO_ACTIVE_LOW>;#address-cells = <1>;#size-cells = <0>;port@1 {reg = <1>;lvds_ep: endpoint {remote-endpoint = <&panel_ep>;};};- };