From 70e75c5266e76c5bc9d30cb1a6296121a872a58d Mon Sep 17 00:00:00 2001 From: Phil Elwell Date: Wed, 18 Apr 2018 17:04:23 +0100 Subject: [PATCH] overlays: Add 'combine' option to i2c overlays The i2c0-bcm2708 and i2c1-bcm2708 overlays allow the I2C pin usage to be changed. The names also suggest they revert to the old i2c_bcm2708 driver, but they don't. The newer i2c_bcm2835 driver forces transactions to be combined where possible, but this breaks some devices. Add an option to disable transaction combining, which is currently implemented by reverting to the old driver. See: https://github.com/raspberrypi/firmware/issues/828 Signed-off-by: Phil Elwell --- arch/arm/boot/dts/overlays/README | 12 ++++++++++-- arch/arm/boot/dts/overlays/i2c0-bcm2708-overlay.dts | 8 ++++++++ arch/arm/boot/dts/overlays/i2c1-bcm2708-overlay.dts | 9 +++++++++ 3 files changed, 27 insertions(+), 2 deletions(-) diff --git a/arch/arm/boot/dts/overlays/README b/arch/arm/boot/dts/overlays/README index 57cba15cfa402..ca69951423226 100644 --- a/arch/arm/boot/dts/overlays/README +++ b/arch/arm/boot/dts/overlays/README @@ -865,8 +865,9 @@ Params: addr Set the address for the BME280, BMP280, DS1621, Name: i2c0-bcm2708 -Info: Enable the i2c_bcm2708 driver for the i2c0 bus. Not all pin combinations - are usable on all platforms. +Info: Change i2c0 pin usage. Not all pin combinations are usable on all + platforms - platforms other then Compute Modules can only use this + to disable transaction combining. Load: dtoverlay=i2c0-bcm2708,= Params: sda0_pin GPIO pin for SDA0 (deprecated - use pins_*) scl0_pin GPIO pin for SCL0 (deprecated - use pins_*) @@ -874,15 +875,22 @@ Params: sda0_pin GPIO pin for SDA0 (deprecated - use pins_*) pins_28_29 Use pins 28 and 29 pins_44_45 Use pins 44 and 45 pins_46_47 Use pins 46 and 47 + combine Allow transactions to be combined (default + "yes") Name: i2c1-bcm2708 +Info: Change i2c1 pin usage. Not all pin combinations are usable on all + platforms - platforms other then Compute Modules can only use this + to disable transaction combining. Info: Enable the i2c_bcm2708 driver for the i2c1 bus Load: dtoverlay=i2c1-bcm2708,= Params: sda1_pin GPIO pin for SDA1 (2 or 44 - default 2) scl1_pin GPIO pin for SCL1 (3 or 45 - default 3) pin_func Alternative pin function (4 (alt0), 6 (alt2) - default 4) + combine Allow transactions to be combined (default + "yes") Name: i2s-gpio28-31 diff --git a/arch/arm/boot/dts/overlays/i2c0-bcm2708-overlay.dts b/arch/arm/boot/dts/overlays/i2c0-bcm2708-overlay.dts index 1f4fc7b570604..9b5776f1bf6a9 100644 --- a/arch/arm/boot/dts/overlays/i2c0-bcm2708-overlay.dts +++ b/arch/arm/boot/dts/overlays/i2c0-bcm2708-overlay.dts @@ -50,6 +50,13 @@ }; }; + fragment@5 { + target = <&i2c0>; + __dormant__ { + compatible = "brcm,bcm2708-i2c"; + }; + }; + __overrides__ { sda0_pin = <&frag1>,"brcm,pins:0"; scl0_pin = <&frag1>,"brcm,pins:4"; @@ -57,5 +64,6 @@ pins_28_29 = <0>,"-1+2-3-4"; pins_44_45 = <0>,"-1-2+3-4"; pins_46_47 = <0>,"-1-2-3+4"; + combine = <0>, "!5"; }; }; diff --git a/arch/arm/boot/dts/overlays/i2c1-bcm2708-overlay.dts b/arch/arm/boot/dts/overlays/i2c1-bcm2708-overlay.dts index 7c69047bcd88a..c9da3eea00122 100644 --- a/arch/arm/boot/dts/overlays/i2c1-bcm2708-overlay.dts +++ b/arch/arm/boot/dts/overlays/i2c1-bcm2708-overlay.dts @@ -26,9 +26,18 @@ brcm,function = <4>; /* alt 0 */ }; }; + + fragment@2 { + target = <&i2c1>; + __dormant__ { + compatible = "brcm,bcm2708-i2c"; + }; + }; + __overrides__ { sda1_pin = <&pins>,"brcm,pins:0"; scl1_pin = <&pins>,"brcm,pins:4"; pin_func = <&pins>,"brcm,function:0"; + combine = <0>, "!2"; }; };