Add Adafruit pitft35 touchscreen support (#1657)

The dts comes from the Adafruit repository

  https://github.com/adafruit/Adafruit-Pi-Kernel-o-Matic/blob/pitft/pitft35r-overlay.dts

Reformatted slightly to match conventions in the pitft28-resistive-overlay.

Signed-off-by: Scott Ellis <[email protected]>

Author: Scott Ellis

arch/arm/boot/dts/overlays/Makefile

@@ -64,6 +64,7 @@ dtbo-$(RPI_DT_OVERLAYS) += piscreen2r.dtbo
 dtbo-$(RPI_DT_OVERLAYS) += pitft22.dtbo
 dtbo-$(RPI_DT_OVERLAYS) += pitft28-capacitive.dtbo
 dtbo-$(RPI_DT_OVERLAYS) += pitft28-resistive.dtbo
+dtbo-$(RPI_DT_OVERLAYS) += pitft35-resistive.dtbo
 dtbo-$(RPI_DT_OVERLAYS) += pps-gpio.dtbo
 dtbo-$(RPI_DT_OVERLAYS) += pwm.dtbo
 dtbo-$(RPI_DT_OVERLAYS) += pwm-2chan.dtbo

arch/arm/boot/dts/overlays/README

@@ -848,6 +848,18 @@ Params: speed                   Display SPI bus speed
         debug                   Debug output level {0-7}
 
 
+Name:   pitft35-resistive
+Info:   Adafruit PiTFT 3.5" resistive touch screen
+Load:   dtoverlay=pitft35-resistive,<param>=<val>
+Params: speed                   Display SPI bus speed
+
+        rotate                  Display rotation {0,90,180,270}
+
+        fps                     Delay between frame updates
+
+        debug                   Debug output level {0-7}
+
+
 Name:   pps-gpio
 Info:   Configures the pps-gpio (pulse-per-second time signal via GPIO).
 Load:   dtoverlay=pps-gpio,<param>=<val>

arch/arm/boot/dts/overlays/pitft35-resistive-overlay.dts

@@ -0,0 +1,121 @@
+/*
+ * Device Tree overlay for Adafruit PiTFT 3.5" resistive touch screen
+ *
+ */
+
+/dts-v1/;
+/plugin/;
+
+/ {
+	compatible = "brcm,bcm2835", "brcm,bcm2708", "brcm,bcm2709";
+
+	fragment@0 {
+		target = <&spi0>;
+		__overlay__ {
+			status = "okay";
+		};
+	};
+
+	fragment@1 {
+		target = <&spidev0>;
+		__overlay__ {
+			status = "disabled";
+		};
+	};
+
+	fragment@2 {
+		target = <&spidev1>;
+		__overlay__ {
+			status = "disabled";
+		};
+	};
+
+	fragment@3 {
+		target = <&gpio>;
+		__overlay__ {
+			pitft_pins: pitft_pins {
+				brcm,pins = <24 25>;
+				brcm,function = <0 1>; /* in out */
+				brcm,pull = <2 0>; /* pullup none */
+			};
+		};
+	};
+
+	fragment@4 {
+		target = <&spi0>;
+		__overlay__ {
+			/* needed to avoid dtc warning */
+			#address-cells = <1>;
+			#size-cells = <0>;
+
+			pitft: pitft@0{
+				compatible = "himax,hx8357d";
+				reg = <0>;
+				pinctrl-names = "default";
+				pinctrl-0 = <&pitft_pins>;
+
+				spi-max-frequency = <32000000>;
+				rotate = <90>;
+				fps = <25>;
+				bgr;
+				buswidth = <8>;
+				dc-gpios = <&gpio 25 0>;
+				debug = <0>;
+			};
+
+			pitft_ts@1 {
+				#address-cells = <1>;
+				#size-cells = <0>;
+				compatible = "st,stmpe610";
+				reg = <1>;
+
+				spi-max-frequency = <500000>;
+				irq-gpio = <&gpio 24 0x2>; /* IRQF_TRIGGER_FALLING */
+				interrupts = <24 2>; /* high-to-low edge triggered */
+				interrupt-parent = <&gpio>;
+				interrupt-controller;
+
+				stmpe_touchscreen {
+					compatible = "st,stmpe-ts";
+					st,sample-time = <4>;
+					st,mod-12b = <1>;
+					st,ref-sel = <0>;
+					st,adc-freq = <2>;
+					st,ave-ctrl = <3>;
+					st,touch-det-delay = <4>;
+					st,settling = <2>;
+					st,fraction-z = <7>;
+					st,i-drive = <0>;
+				};
+
+				stmpe_gpio: stmpe_gpio {
+					#gpio-cells = <2>;
+					compatible = "st,stmpe-gpio";
+					/*
+					 * only GPIO2 is wired/available
+					 * and it is wired to the backlight
+					 */
+					st,norequest-mask = <0x7b>;
+				};
+			};
+		};
+	};
+
+	fragment@5 {
+		target-path = "/soc";
+		__overlay__ {
+			backlight {
+				compatible = "gpio-backlight";
+				gpios = <&stmpe_gpio 2 0>;
+				default-on;
+			};
+		};
+	};
+
+	__overrides__ {
+		speed =   <&pitft>,"spi-max-frequency:0";
+		rotate =  <&pitft>,"rotate:0";
+		fps =     <&pitft>,"fps:0";
+		debug =   <&pitft>,"debug:0";
+	};
+};

arch/arm/configs/bcm2709_defconfig

@@ -1111,6 +1111,7 @@ CONFIG_FB_TFT_BD663474=m
 CONFIG_FB_TFT_HX8340BN=m
 CONFIG_FB_TFT_HX8347D=m
 CONFIG_FB_TFT_HX8353D=m
+CONFIG_FB_TFT_HX8357D=m
 CONFIG_FB_TFT_ILI9163=m
 CONFIG_FB_TFT_ILI9320=m
 CONFIG_FB_TFT_ILI9325=m

arch/arm/configs/bcmrpi_defconfig

@@ -1117,6 +1117,7 @@ CONFIG_FB_TFT_BD663474=m
 CONFIG_FB_TFT_HX8340BN=m
 CONFIG_FB_TFT_HX8347D=m
 CONFIG_FB_TFT_HX8353D=m
+CONFIG_FB_TFT_HX8357D=m
 CONFIG_FB_TFT_ILI9163=m
 CONFIG_FB_TFT_ILI9320=m
 CONFIG_FB_TFT_ILI9325=m