bcm27xx: add support for linux v5.15

Build system: x86_64
Build-tested: bcm2708, bcm2709, bcm2710, bcm2711
Run-tested: bcm2708/RPiB+, bcm2709/RPi3B, bcm2710/RPi3B, bcm2711/RPi4B

Signed-off-by: Marty Jones <mj8263788@gmail.com>
Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>

1 files changed, 107 insertions, 0 deletions

diff --git a/target/linux/bcm27xx/patches-5.15/950-0665-dtoverlays-Add-pwm-backlight-option-to-vc4-kms-dpi-g.patch b/target/linux/bcm27xx/patches-5.15/950-0665-dtoverlays-Add-pwm-backlight-option-to-vc4-kms-dpi-g.patch
new file mode 100644
index 0000000000..5b0243472c
--- /dev/null
+++ b/target/linux/bcm27xx/patches-5.15/950-0665-dtoverlays-Add-pwm-backlight-option-to-vc4-kms-dpi-g.patch
@@ -0,0 +1,107 @@
+From 7ec32023e6ad31c242e2acc179fd35084fa9cea5 Mon Sep 17 00:00:00 2001
+From: Dave Stevenson <dave.stevenson@raspberrypi.com>
+Date: Fri, 21 Jan 2022 14:22:01 +0000
+Subject: [PATCH] dtoverlays: Add pwm backlight option to
+ vc4-kms-dpi-generic
+
+Adds the option of a PWM controlled backlight on a generic
+DPI display.
+
+Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
+---
+ arch/arm/boot/dts/overlays/README             | 17 +++++++
+ .../overlays/vc4-kms-dpi-generic-overlay.dts  | 51 +++++++++++++++++++
+ 2 files changed, 68 insertions(+)
+
+--- a/arch/arm/boot/dts/overlays/README
++++ b/arch/arm/boot/dts/overlays/README
+@@ -3644,6 +3644,23 @@ Params: clock-frequency         Display
+                                 value. NB also overridden by rgbXXX overrides.
+         backlight-gpio          Defines a GPIO to be used for backlight control
+                                 (default of none).
++        backlight-pwm           Defines a PWM channel to be used for backlight
++                                control (default of none). NB Disables audio
++                                headphone output as that also uses PWM.
++        backlight-pwm-chan      Choose channel on &pwm node for backlight
++                                control.
++                                (default 0).
++        backlight-pwm-gpio      GPIO pin to be used for the PWM backlight. See
++                                pwm-2chan for valid options.
++                                (default 18 - note this can only work with
++                                 rgb666-padhi).
++        backlight-pwm-func      Pin function of GPIO used for the PWM
++                                backlight.
++                                See pwm-2chan for valid options.
++                                (default 2).
++        backlight-def-brightness
++                                Set the default brightness. Normal range 1-16.
++                                (default 16).
+ 
+ 
+ Name:   vc4-kms-dsi-7inch
+--- a/arch/arm/boot/dts/overlays/vc4-kms-dpi-generic-overlay.dts
++++ b/arch/arm/boot/dts/overlays/vc4-kms-dpi-generic-overlay.dts
+@@ -80,6 +80,52 @@
+ 		};
+ 	};
+ 
++	fragment@4 {
++		target = <&panel>;
++		__dormant__  {
++			backlight = <&backlight_pwm>;
++		};
++	};
++
++	fragment@5 {
++		target-path = "/";
++		__dormant__  {
++			backlight_pwm: backlight_pwm {
++				compatible = "pwm-backlight";
++				brightness-levels = <0 6 8 12 16 24 32 40 48 64 96 128 160 192 224 255>;
++				default-brightness-level = <16>;
++				pwms = <&pwm 0 200000>;
++			};
++		};
++	};
++
++	fragment@6 {
++		target = <&pwm>;
++		__dormant__ {
++			pinctrl-names = "default";
++			pinctrl-0 = <&pwm_pins>;
++			assigned-clock-rates = <1000000>;
++			status = "okay";
++		};
++	};
++
++	fragment@7 {
++		target = <&gpio>;
++		__dormant__ {
++			pwm_pins: pwm_pins {
++				brcm,pins = <18>;
++				brcm,function = <2>; /* Alt5 */
++			};
++		};
++	};
++
++	fragment@8 {
++		target = <&audio>;
++		__dormant__  {
++		    brcm,disable-headphones;
++		};
++	};
++
+ 	__overrides__ {
+ 		clock-frequency = <&timing>, "clock-frequency:0";
+ 		hactive = <&timing>, "hactive:0";
+@@ -107,5 +153,10 @@
+ 		bus-format = <&panel>, "bus-format:0";
+ 		backlight-gpio = <0>, "+2+3",
+ 			<&backlight>, "gpios:4";
++		backlight-pwm = <0>, "+4+5+6+7+8";
++		backlight-pwm-chan = <&backlight_pwm>, "pwms:4";
++		backlight-pwm-gpio = <&pwm_pins>, "brcm,pins:0";
++		backlight-pwm-func = <&pwm_pins>, "brcm,function:0";
++		backlight-def-brightness = <&backlight_pwm>, "default-brightness-level:0";
+ 	};
+ };