Re: [PATCH 1/2] ARM: dts: bcm2*: Demux i2c0 with a pinctrl

Stefan Wahren
2022-02-09T17:27:59Z

Hi Detlev,

Am 09.02.22 um 17:25 schrieb Detlev Casanova:
> The i2c0 device has 2 different busses controlled by a pinctrl.
> This commit separates the device node into 2 i2c devices:
> * pin 0: Base i2c bus
> * pin 44: DSI i2c bus
>
> i2c0 is renamed to i2c0if so that device-trees referencing i2c0 don't
> break and use the i2c0 node defined in i2c0mux node.
>
> i2c_csi_dsi can be used to control devices via the DSI i2c bus, used for
> DSI displays.
>
> Signed-off-by: Detlev Casanova <detlev.casanova@collabora.com>

just a note: Uwe sends a similiar approach for the RTC on CM4 [1] which
hasn't applied yet.

[1] - https://www.spinics.net/lists/arm-kernel/msg944330.html

> ---
> arch/arm/boot/dts/bcm2711-rpi-4-b.dts | 1 +
> arch/arm/boot/dts/bcm2711.dtsi | 2 +-
> arch/arm/boot/dts/bcm2835-rpi.dtsi | 9 ++++---
> .../boot/dts/bcm283x-rpi-i2c0mux_0_44.dtsi | 4 +++
> arch/arm/boot/dts/bcm283x.dtsi | 26 ++++++++++++++++++-
> 5 files changed, 37 insertions(+), 5 deletions(-)
> create mode 100644 arch/arm/boot/dts/bcm283x-rpi-i2c0mux_0_44.dtsi
>
> diff --git a/arch/arm/boot/dts/bcm2711-rpi-4-b.dts b/arch/arm/boot/dts/bcm2711-rpi-4-b.dts
> index 4432412044de..5dcce58817e6 100644
> --- a/arch/arm/boot/dts/bcm2711-rpi-4-b.dts
> +++ b/arch/arm/boot/dts/bcm2711-rpi-4-b.dts
> @@ -4,6 +4,7 @@
> #include "bcm2711-rpi.dtsi"
> #include "bcm283x-rpi-usb-peripheral.dtsi"
> #include "bcm283x-rpi-wifi-bt.dtsi"
> +#include "bcm283x-rpi-i2c0mux_0_44.dtsi"
>
> / {
> compatible = "raspberrypi,4-model-b", "brcm,bcm2711";
> diff --git a/arch/arm/boot/dts/bcm2711.dtsi b/arch/arm/boot/dts/bcm2711.dtsi
> index 3b60297af7f6..bf6e8251c2c7 100644
> --- a/arch/arm/boot/dts/bcm2711.dtsi
> +++ b/arch/arm/boot/dts/bcm2711.dtsi
> @@ -1037,7 +1037,7 @@ &cma {
> alloc-ranges = <0x0 0x00000000 0x40000000>;
> };
>
> -&i2c0 {
> +&i2c0if {
> compatible = "brcm,bcm2711-i2c", "brcm,bcm2835-i2c";
> interrupts = <GIC_SPI 117 IRQ_TYPE_LEVEL_HIGH>;
> };
> diff --git a/arch/arm/boot/dts/bcm2835-rpi.dtsi b/arch/arm/boot/dts/bcm2835-rpi.dtsi
> index 87ddcad76083..1e38f9f0e80e 100644
> --- a/arch/arm/boot/dts/bcm2835-rpi.dtsi
> +++ b/arch/arm/boot/dts/bcm2835-rpi.dtsi
> @@ -49,13 +49,16 @@ alt0: alt0 {
> };
> };
>
> -&i2c0 {
> - pinctrl-names = "default";
> - pinctrl-0 = <&i2c0_gpio0>;
> +&i2c0if {
> status = "okay";
> clock-frequency = <100000>;
> };
>
> +&i2c0mux {
> + pinctrl-0 = <&i2c0_gpio0>;
> + status = "okay";
> +};
> +
> &i2c1 {
> pinctrl-names = "default";
> pinctrl-0 = <&i2c1_gpio2>;
> diff --git a/arch/arm/boot/dts/bcm283x-rpi-i2c0mux_0_44.dtsi b/arch/arm/boot/dts/bcm283x-rpi-i2c0mux_0_44.dtsi
> new file mode 100644
> index 000000000000..119946d878db
> --- /dev/null
> +++ b/arch/arm/boot/dts/bcm283x-rpi-i2c0mux_0_44.dtsi
> @@ -0,0 +1,4 @@
> +&i2c0mux {
> + pinctrl-0 = <&i2c0_gpio0>;
> + pinctrl-1 = <&i2c0_gpio44>;
> +};
> diff --git a/arch/arm/boot/dts/bcm283x.dtsi b/arch/arm/boot/dts/bcm283x.dtsi
> index a3e06b680947..06d04cde52b9 100644
> --- a/arch/arm/boot/dts/bcm283x.dtsi
> +++ b/arch/arm/boot/dts/bcm283x.dtsi
> @@ -334,7 +334,7 @@ spi: spi@7e204000 {
> status = "disabled";
> };
>
> - i2c0: i2c@7e205000 {
> + i2c0if: i2c@7e205000 {
> compatible = "brcm,bcm2835-i2c";
> reg = <0x7e205000 0x200>;
> interrupts = <2 21>;
> @@ -344,6 +344,30 @@ i2c0: i2c@7e205000 {
> status = "disabled";
> };
>
> + i2c0mux: i2c0mux {
> + compatible = "i2c-mux-pinctrl";
> + #address-cells = <1>;
> + #size-cells = <0>;
> +
> + i2c-parent = <&i2c0if>;
> +
> + pinctrl-names = "i2c0", "i2c_csi_dsi";
> +
> + status = "disabled";
> +
> + i2c0: i2c@0 {
> + reg = <0>;
> + #address-cells = <1>;
> + #size-cells = <0>;
> + };
> +
> + i2c_csi_dsi: i2c@1 {
> + reg = <1>;
> + #address-cells = <1>;
> + #size-cells = <0>;
> + };
> + };
> +
> dpi: dpi@7e208000 {
> compatible = "brcm,bcm2835-dpi";
> reg = <0x7e208000 0x8c>;