On Mon 02 Oct 07:13 PDT 2017, Todor Tomov wrote:
> diff --git a/Documentation/devicetree/bindings/i2c/i2c-qcom-cci.txt b/Documentation/devicetree/bindings/i2c/i2c-qcom-cci.txt
> new file mode 100644
> index 0000000..f4c5338
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/i2c/i2c-qcom-cci.txt
> @@ -0,0 +1,55 @@
> +Qualcomm Camera Control Interface I2C controller
Well, it's not a I2C controller, it is a MIPI CCI controller.
> +
> +Required properties:
> + - compatible: Should be one of:
> + - "qcom,cci-v1.0.8" for 8916;
> + - "qcom,cci-v1.4.0" for 8996.
> + - #address-cells: Should be <1>.
> + - #size-cells: Should be <0>.
> + - reg: Base address of the controller and length of memory mapped region.
> + - reg-names: Should be "cci".
No need for reg-names, as we only have one.
> + - interrupts: Specifier for CCI interrupt.
> + - interrupt-names: Should be "cci".
No need for interrupt-names, as we only have one.
> + - clocks: List of clock specifiers, one for each entry in clock-names.
> + - clock-names: Should contain:
> + - "mmss_mmagic_ahb" - on 8996 only;
> + - "camss_top_ahb";
> + - "cci_ahb";
> + - "cci";
> + - "camss_ahb".
> + - pinctrl-names: Should contain only one value - "default".
> + - pinctrl-0: Pin control group to be used for this controller.
No need to document that the node can have the default pinctrl
properties.
> +
> +
> +Required properties on 8996:
> + - power-domains: Power domain specifier.
> +
> +Optional:
> + - clock-frequency: Desired I2C bus clock frequency in Hz, defaults to 100 kHz
> + if omitted.
> +
> +Example:
> +
> + cci: qcom,cci@a0c000 {
Don't do qcom, in the node name, and there's probably no reason to have
a label for this node either. So just make it
cci@a0c000 {
> + compatible = "qcom,cci-v1.4.0";
> + #address-cells = <1>;
> + #size-cells = <0>;
> + reg = <0xa0c000 0x1000>;
> + reg-names = "cci";
> + interrupts = <GIC_SPI 295 IRQ_TYPE_EDGE_RISING>;
> + interrupt-names = "cci";
> + power-domains = <&mmcc CAMSS_GDSC>;
> + clocks = <&mmcc MMSS_MMAGIC_AHB_CLK>,
> + <&mmcc CAMSS_TOP_AHB_CLK>,
> + <&mmcc CAMSS_CCI_AHB_CLK>,
> + <&mmcc CAMSS_CCI_CLK>,
> + <&mmcc CAMSS_AHB_CLK>;
> + clock-names = "mmss_mmagic_ahb",
> + "camss_top_ahb",
> + "cci_ahb",
> + "cci",
> + "camss_ahb";
> + pinctrl-names = "default";
> + pinctrl-0 = <&cci0_default>;
> + clock-frequency = <400000>;
> + };
In the case of this single cci block having two masters we need a way to
describe the two sets of clients. I think the two options we have are:
cci {
client {
reg = <0 0x2c>;
};
};
The reg here being <master address>
or:
cci {
master0 {
client {
reg = <0x2c>;
};
};
};
The name "master0" could be made significant and picked up by name, and
in the case of single-master this level could be omitted.
I like the first one, but it looks really hard to get implemented in
Linux, based on the i2c core's expectation that #address-cells is 1. So
I think the latter is the favourable option.
Regards,
Bjorn
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