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250 lines
8.2 KiB
250 lines
8.2 KiB
From 4eac708a344a2fc86a1cacebedc7cd5650d83231 Mon Sep 17 00:00:00 2001
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From: Phil Elwell <phil@raspberrypi.org>
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Date: Mon, 17 Aug 2015 10:49:44 +0100
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Subject: [PATCH 154/222] BCM270X_DT: Add pwm and pwm-2chan overlays
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From the README entries:
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Legal pin,function combinations for each channel:
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PWM0: 12,4(Alt0) 18,2(Alt5) 40,4(Alt0) 52,5(Alt1)
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PWM1: 13,4(Alt0) 19,2(Alt5) 41,4(Alt0) 45,4(Alt0) 53,5(Alt1)
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N.B.:
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1) Pin 18 is the only one available on all platforms, and
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it is the one used by the I2S audio interface.
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Pins 12 and 13 might be better choices on an A+, B+ or Pi2.
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2) The onboard analogue audio output uses both PWM channels.
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3) So be careful mixing audio and PWM.
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4) Currently the clock must have been enabled and configured
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by other means.
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See: https://github.com/raspberrypi/linux/issues/756
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---
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arch/arm/boot/dts/bcm2708_common.dtsi | 16 +++++++++
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arch/arm/boot/dts/overlays/Makefile | 2 ++
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arch/arm/boot/dts/overlays/README | 41 +++++++++++++++++++++
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arch/arm/boot/dts/overlays/pwm-2chan-overlay.dts | 46 ++++++++++++++++++++++++
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arch/arm/boot/dts/overlays/pwm-overlay.dts | 42 ++++++++++++++++++++++
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arch/arm/configs/bcm2709_defconfig | 1 +
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arch/arm/configs/bcmrpi_defconfig | 1 +
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drivers/pwm/Kconfig | 2 +-
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8 files changed, 150 insertions(+), 1 deletion(-)
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create mode 100644 arch/arm/boot/dts/overlays/pwm-2chan-overlay.dts
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create mode 100644 arch/arm/boot/dts/overlays/pwm-overlay.dts
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--- a/arch/arm/boot/dts/bcm2708_common.dtsi
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+++ b/arch/arm/boot/dts/bcm2708_common.dtsi
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@@ -154,6 +154,14 @@
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status = "disabled";
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};
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+ pwm: pwm@7e20c000 {
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+ compatible = "brcm,bcm2835-pwm";
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+ reg = <0x7e20c000 0x28>;
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+ clocks = <&clk_pwm>;
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+ #pwm-cells = <2>;
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+ status = "disabled";
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+ };
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+
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uart1: uart@7e215040 {
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compatible = "brcm,bcm2835-aux-uart", "ns16550";
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reg = <0x7e215040 0x40>;
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@@ -279,6 +287,14 @@
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clock-output-names = "apb_pclk";
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clock-frequency = <126000000>;
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};
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+
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+ clk_pwm: clock@5 {
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+ compatible = "fixed-clock";
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+ reg = <3>;
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+ #clock-cells = <0>;
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+ clock-output-names = "pwm";
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+ clock-frequency = <100000000>;
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+ };
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};
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__overrides__ {
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--- a/arch/arm/boot/dts/overlays/Makefile
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+++ b/arch/arm/boot/dts/overlays/Makefile
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@@ -35,6 +35,8 @@ dtb-$(RPI_DT_OVERLAYS) += mz61581-overla
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dtb-$(RPI_DT_OVERLAYS) += piscreen-overlay.dtb
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dtb-$(RPI_DT_OVERLAYS) += pitft28-resistive-overlay.dtb
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dtb-$(RPI_DT_OVERLAYS) += pps-gpio-overlay.dtb
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+dtb-$(RPI_DT_OVERLAYS) += pwm-overlay.dtb
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+dtb-$(RPI_DT_OVERLAYS) += pwm-2chan-overlay.dtb
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dtb-$(RPI_DT_OVERLAYS) += rpi-dac-overlay.dtb
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dtb-$(RPI_DT_OVERLAYS) += rpi-display-overlay.dtb
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dtb-$(RPI_DT_OVERLAYS) += rpi-ft5406-overlay.dtb
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--- a/arch/arm/boot/dts/overlays/README
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+++ b/arch/arm/boot/dts/overlays/README
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@@ -410,6 +410,47 @@ Load: dtoverlay=pps-gpio,<param>=<val>
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Params: gpiopin Input GPIO (default "18")
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+Name: pwm
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+Info: Configures a single PWM channel
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+ Legal pin,function combinations for each channel:
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+ PWM0: 12,4(Alt0) 18,2(Alt5) 40,4(Alt0) 52,5(Alt1)
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+ PWM1: 13,4(Alt0) 19,2(Alt5) 41,4(Alt0) 45,4(Alt0) 53,5(Alt1)
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+ N.B.:
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+ 1) Pin 18 is the only one available on all platforms, and
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+ it is the one used by the I2S audio interface.
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+ Pins 12 and 13 might be better choices on an A+, B+ or Pi2.
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+ 2) The onboard analogue audio output uses both PWM channels.
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+ 3) So be careful mixing audio and PWM.
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+ 4) Currently the clock must have been enabled and configured
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+ by other means.
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+Load: dtoverlay=pwm-2chan,<param>=<val>
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+Load: dtoverlay=pwm,<param>=<val>
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+Params: pin Output pin (default 18) - see table
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+ func Pin function (default 2 = Alt5) - see above
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+ clock PWM clock frequency (informational)
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+
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+
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+Name: pwm-2chan
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+Info: Configures both PWM channels
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+ Legal pin,function combinations for each channel:
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+ PWM0: 12,4(Alt0) 18,2(Alt5) 40,4(Alt0) 52,5(Alt1)
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+ PWM1: 13,4(Alt0) 19,2(Alt5) 41,4(Alt0) 45,4(Alt0) 53,5(Alt1)
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+ N.B.:
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+ 1) Pin 18 is the only one available on all platforms, and
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+ it is the one used by the I2S audio interface.
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+ Pins 12 and 13 might be better choices on an A+, B+ or Pi2.
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+ 2) The onboard analogue audio output uses both PWM channels.
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+ 3) So be careful mixing audio and PWM.
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+ 4) Currently the clock must have been enabled and configured
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+ by other means.
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+Load: dtoverlay=pwm-2chan,<param>=<val>
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+Params: pin Output pin (default 18) - see table
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+ pin2 Output pin for other channel (default 19)
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+ func Pin function (default 2 = Alt5) - see above
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+ func2 Function for pin2 (default 2 = Alt5)
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+ clock PWM clock frequency (informational)
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+
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+
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Name: rpi-dac
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Info: Configures the RPi DAC audio card
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Load: dtoverlay=rpi-dac
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--- /dev/null
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+++ b/arch/arm/boot/dts/overlays/pwm-2chan-overlay.dts
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@@ -0,0 +1,46 @@
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+/dts-v1/;
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+/plugin/;
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+
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+/*
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+This is the 2-channel overlay - only use it if you need both channels.
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+
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+Legal pin,function combinations for each channel:
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+ PWM0: 12,4(Alt0) 18,2(Alt5) 40,4(Alt0) 52,5(Alt1)
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+ PWM1: 13,4(Alt0) 19,2(Alt5) 41,4(Alt0) 45,4(Alt0) 53,5(Alt1)
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+
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+N.B.:
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+ 1) Pin 18 is the only one available on all platforms, and
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+ it is the one used by the I2S audio interface.
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+ Pins 12 and 13 might be better choices on an A+, B+ or Pi2.
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+ 2) The onboard analogue audio output uses both PWM channels.
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+ 3) So be careful mixing audio and PWM.
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+*/
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+
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+/ {
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+ fragment@0 {
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+ target = <&gpio>;
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+ __overlay__ {
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+ pwm_pins: pwm_pins {
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+ brcm,pins = <18 19>;
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+ brcm,function = <2 2>; /* Alt5 */
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+ };
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+ };
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+ };
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+
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+ fragment@1 {
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+ target = <&pwm>;
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+ __overlay__ {
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+ pinctrl-names = "default";
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+ pinctrl-0 = <&pwm_pins>;
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+ status = "okay";
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+ };
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+ };
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+
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+ __overrides__ {
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+ pin = <&pwm_pins>,"brcm,pins:0";
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+ pin2 = <&pwm_pins>,"brcm,pins:4";
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+ func = <&pwm_pins>,"brcm,function:0";
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+ func2 = <&pwm_pins>,"brcm,function:4";
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+ clock = <&clk_pwm>,"clock-frequency:0";
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+ };
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+};
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--- /dev/null
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+++ b/arch/arm/boot/dts/overlays/pwm-overlay.dts
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@@ -0,0 +1,42 @@
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+/dts-v1/;
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+/plugin/;
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+
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+/*
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+Legal pin,function combinations for each channel:
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+ PWM0: 12,4(Alt0) 18,2(Alt5) 40,4(Alt0) 52,5(Alt1)
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+ PWM1: 13,4(Alt0) 19,2(Alt5) 41,4(Alt0) 45,4(Alt0) 53,5(Alt1)
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+
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+N.B.:
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+ 1) Pin 18 is the only one available on all platforms, and
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+ it is the one used by the I2S audio interface.
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+ Pins 12 and 13 might be better choices on an A+, B+ or Pi2.
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+ 2) The onboard analogue audio output uses both PWM channels.
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+ 3) So be careful mixing audio and PWM.
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+*/
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+
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+/ {
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+ fragment@0 {
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+ target = <&gpio>;
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+ __overlay__ {
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+ pwm_pins: pwm_pins {
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+ brcm,pins = <18>;
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+ brcm,function = <2>; /* Alt5 */
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+ };
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+ };
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+ };
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+
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+ fragment@1 {
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+ target = <&pwm>;
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+ __overlay__ {
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+ pinctrl-names = "default";
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+ pinctrl-0 = <&pwm_pins>;
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+ status = "okay";
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+ };
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+ };
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+
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+ __overrides__ {
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+ pin = <&pwm_pins>,"brcm,pins:0";
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+ func = <&pwm_pins>,"brcm,function:0";
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+ clock = <&clk_pwm>,"clock-frequency:0";
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+ };
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+};
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--- a/arch/arm/configs/bcm2709_defconfig
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+++ b/arch/arm/configs/bcm2709_defconfig
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@@ -1089,6 +1089,7 @@ CONFIG_IIO_BUFFER=y
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CONFIG_IIO_BUFFER_CB=y
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CONFIG_IIO_KFIFO_BUF=m
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CONFIG_DHT11=m
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+CONFIG_PWM_BCM2835=m
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CONFIG_RASPBERRYPI_FIRMWARE=y
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CONFIG_EXT4_FS=y
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CONFIG_EXT4_FS_POSIX_ACL=y
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--- a/arch/arm/configs/bcmrpi_defconfig
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+++ b/arch/arm/configs/bcmrpi_defconfig
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@@ -1082,6 +1082,7 @@ CONFIG_IIO_BUFFER=y
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CONFIG_IIO_BUFFER_CB=y
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CONFIG_IIO_KFIFO_BUF=m
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CONFIG_DHT11=m
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+CONFIG_PWM_BCM2835=m
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CONFIG_RASPBERRYPI_FIRMWARE=y
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CONFIG_EXT4_FS=y
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CONFIG_EXT4_FS_POSIX_ACL=y
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--- a/drivers/pwm/Kconfig
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+++ b/drivers/pwm/Kconfig
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@@ -85,7 +85,7 @@ config PWM_BCM_KONA
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config PWM_BCM2835
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tristate "BCM2835 PWM support"
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- depends on ARCH_BCM2835
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+ depends on ARCH_BCM2835 || ARCH_BCM2708 || ARCH_BCM2709
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help
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PWM framework driver for BCM2835 controller (Raspberry Pi)
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