Generate panel definition for device tree

qcom,mdss-dsi-lane-map tends to be hard to get right on mainline
if it differs from the default (lane_map_0123). This is because the
definition on mainline is inversed (physical -> logical lanes), while
downstream uses logical -> physical lanes.

Let's also generate a .dtsi to make that more easy.

Author: stephan-gh

driver.py

@@ -452,6 +452,8 @@ def generate_driver(p: Panel, options: Options) -> None:
 		# Unknown vendor
 		compatible = 'mdss,' + '-'.join(compatible)
 
+	options.compatible = compatible
+
 	module = f"panel-{dash_id}"
 	with open(f'{p.id}/{module}.c', 'w') as f:
 		f.write(f'''\

dtsi.py

@@ -0,0 +1,51 @@
+from generator import Options
+from panel import Panel, BacklightControl
+
+
+def generate_backlight(p: Panel):
+	if p.backlight == BacklightControl.DCS:
+		return ""
+	return "\t\tbacklight = <&backlight>;\n"
+
+
+def generate_supplies(options: Options):
+	s = ""
+	if options.regulator:
+		for r in options.regulator:
+			s += f"\t\t{r}-supply = <&...>;\n"
+	return s
+
+
+def generate_gpios(options: Options):
+	s = ""
+	for r in options.gpios:
+		s += f"\t\t{r}-gpios = <&msmgpio XY GPIO_ACTIVE_HIGH>;\n"
+	return s
+
+
+def generate_panel_dtsi(p: Panel, options: Options) -> None:
+	name = p.short_id.replace('_', '-')
+	with open(f'{p.id}/panel-{name}.dtsi', 'w') as f:
+		f.write(f'''\
+&dsi0 {{
+	panel@0 {{
+		compatible = "{options.compatible}";
+		reg = <0>;
+
+{generate_backlight(p)}\
+{generate_supplies(options)}\
+{generate_gpios(options)}\
+
+		port {{
+			panel_in: endpoint {{
+				remote-endpoint = <&dsi0_out>;
+			}};
+		}};
+	}};
+}};
+
+&dsi0_out {{
+	data-lanes = <{' '.join(map(str, p.lane_map.phys2log[:p.lanes]))}>;
+	remote-endpoint = <&panel_in>;
+}};
+''')

fdt2.py

@@ -34,9 +34,14 @@ def getprop_int32(self, nodeoffset, prop_name, default=0):
 		return prop.as_int32()
 
 
+def property_is_str(self):
+	return self[-1] == 0 and 0 not in self[:-1]
+
+
 def property_as_uint32_array(self):
 	num = int(len(self) / 4)
 	return list(struct.unpack('>' + ('L' * num), self))
 
 
+Property.is_str = property_is_str
 Property.as_uint32_array = property_as_uint32_array

generator.py

@@ -13,3 +13,7 @@ class Options:
 	backlight_gpio: bool
 	ignore_wait: int
 	dumb_dcs: bool
+
+	# Added by panel driver generator
+	compatible: str
+	gpios: List[str]

lmdpdg.py

@@ -5,6 +5,7 @@
 
 import generator
 from driver import generate_driver
+from dtsi import generate_panel_dtsi
 from fdt2 import Fdt2
 from panel import Panel
 from simple import generate_panel_simple
@@ -22,6 +23,7 @@ def generate(p: Panel, options: generator.Options) -> None:
 
 	generate_panel_simple(p)
 	generate_driver(p, options)
+	generate_panel_dtsi(p, options)
 
 
 parser = argparse.ArgumentParser(

panel.py

@@ -38,7 +38,7 @@ def __new__(cls, value: str, flags: List[str]) -> TrafficMode:
 
 	@staticmethod
 	def parse(prop: libfdt.Property) -> Optional[TrafficMode]:
-		if prop[-1] == 0:  # Null terminated string
+		if prop.is_str():
 			return TrafficMode(prop.as_str())
 
 		print(f"WARNING: qcom,mdss-dsi-traffic-mode is not a null terminated string:", prop)
@@ -55,6 +55,40 @@ def parse(prop: libfdt.Property) -> Optional[TrafficMode]:
 		print("Falling back to MIPI_DSI_MODE_VIDEO_SYNC_PULSE")
 		return TrafficMode.SYNC_PULSE
 
+
+@unique
+class LaneMap(Enum):
+	MAP_0123 = [0, 1, 2, 3]
+	MAP_3012 = [3, 0, 1, 2]
+	MAP_2301 = [2, 3, 0, 1]
+	MAP_1230 = [1, 2, 3, 0]
+	MAP_0321 = [0, 3, 2, 1]
+	MAP_1032 = [1, 0, 3, 2]
+	MAP_2103 = [2, 1, 0, 3]
+	MAP_3210 = [3, 2, 1, 0]
+
+	def __new__(cls, log2phys: List[int]) -> LaneMap:
+		obj = object.__new__(cls)
+		obj._value_ = "lane_map_" + ''.join(map(str, log2phys))
+		# Logical lane -> physical lane (used in downstream)
+		obj.log2phys = log2phys
+		# Physical lane -> logical lane (used in mainline)
+		obj.phys2log = [0, 0, 0, 0]
+		for i, n in enumerate(log2phys):
+			obj.phys2log[n] = i
+		return obj
+
+	@staticmethod
+	def parse(prop: Optional[libfdt.Property]) -> LaneMap:
+		if not prop:
+			return LaneMap.MAP_0123
+		if prop.is_str():  # Null terminated string
+			return LaneMap(prop.as_str())
+
+		print(f"WARNING: qcom,mdss-dsi-lane-map is not a null terminated string:", prop)
+		return LaneMap.MAP_0123
+
+
 @unique
 class BacklightControl(Enum):
 	PWM = 'bl_ctrl_pwm'
@@ -171,6 +205,7 @@ def __init__(self, name: str, fdt: Fdt2, node: int) -> None:
 		self.lanes = 0
 		while fdt.getprop_or_none(node, f'qcom,mdss-dsi-lane-{self.lanes}-state') is not None:
 			self.lanes += 1
+		self.lane_map = LaneMap.parse(fdt.getprop_or_none(node, 'qcom,mdss-dsi-lane-map'))
 
 		self.flags = self.mode.flags + self.traffic_mode.flags