[RFD]: Solving qcom unique unit address warnings

[Vinod Koul <vkoul@kernel.org>]

Hi Rob,

On all Qualcomm SoCs there exists QUP serial engine. These engines are
loaded with a firmware by bootloader and can support a specific protocol
like I2C/SPI/uart etc.

Since the serial engine can support different protocols we end up
describing all the supported ones for this, as illustrated below from
sdm845 dts upstream:

		qupv3_id_0: geniqup@8c0000 {
			compatible = "qcom,geni-se-qup";
			reg = <0 0x008c0000 0 0x6000>;
			clock-names = "m-ahb", "s-ahb";
			clocks = <&gcc GCC_QUPV3_WRAP_0_M_AHB_CLK>,
				 <&gcc GCC_QUPV3_WRAP_0_S_AHB_CLK>;
			iommus = <&apps_smmu 0x3 0x0>;
			#address-cells = <2>;
			#size-cells = <2>;
			ranges;
			interconnects = <&aggre1_noc MASTER_QUP_1 0 &config_noc SLAVE_BLSP_1 0>;
			interconnect-names = "qup-core";
			status = "disabled";

			i2c0: i2c@880000 {
				compatible = "qcom,geni-i2c";
				reg = <0 0x00880000 0 0x4000>;
				clock-names = "se";
				clocks = <&gcc GCC_QUPV3_WRAP0_S0_CLK>;
				pinctrl-names = "default";
				pinctrl-0 = <&qup_i2c0_default>;
				interrupts = <GIC_SPI 601 IRQ_TYPE_LEVEL_HIGH>;
				#address-cells = <1>;
				#size-cells = <0>;
				power-domains = <&rpmhpd SDM845_CX>;
				operating-points-v2 = <&qup_opp_table>;
				interconnects = <&aggre1_noc MASTER_QUP_1 0 &config_noc SLAVE_BLSP_1 0>,
						<&gladiator_noc MASTER_APPSS_PROC 0 &config_noc SLAVE_BLSP_1 0>,
						<&aggre1_noc MASTER_QUP_1 0 &mem_noc SLAVE_EBI1 0>;
				interconnect-names = "qup-core", "qup-config", "qup-memory";
				status = "disabled";
			};

			spi0: spi@880000 {
				compatible = "qcom,geni-spi";
				reg = <0 0x00880000 0 0x4000>;
				clock-names = "se";
				clocks = <&gcc GCC_QUPV3_WRAP0_S0_CLK>;
				pinctrl-names = "default";
				pinctrl-0 = <&qup_spi0_default>;
				interrupts = <GIC_SPI 601 IRQ_TYPE_LEVEL_HIGH>;
				#address-cells = <1>;
				#size-cells = <0>;
				interconnects = <&aggre1_noc MASTER_QUP_1 0 &config_noc SLAVE_BLSP_1 0>,
						<&gladiator_noc MASTER_APPSS_PROC 0 &config_noc SLAVE_BLSP_1 0>;
				interconnect-names = "qup-core", "qup-config";
				status = "disabled";
			};

			uart0: serial@880000 {
				compatible = "qcom,geni-uart";
				reg = <0 0x00880000 0 0x4000>;
				clock-names = "se";
				clocks = <&gcc GCC_QUPV3_WRAP0_S0_CLK>;
				pinctrl-names = "default";
				pinctrl-0 = <&qup_uart0_default>;
				interrupts = <GIC_SPI 601 IRQ_TYPE_LEVEL_HIGH>;
				power-domains = <&rpmhpd SDM845_CX>;
				operating-points-v2 = <&qup_opp_table>;
				interconnects = <&aggre1_noc MASTER_QUP_1 0 &config_noc SLAVE_BLSP_1 0>,
						<&gladiator_noc MASTER_APPSS_PROC 0 &config_noc SLAVE_BLSP_1 0>;
				interconnect-names = "qup-core", "qup-config";
				status = "disabled";
			};


The problem comes with all these nodes having same unit addresses. This
is adding to ~2K warning for unique_unit_address upstream.

So to solve this we thought of creating a qup se node and then query the
protocol supported from the firmware on boot and create a child
auxillary_device. The problem with that approach is another warning
"node name for SPI buses should be 'spi'"! So that would not help

Now, I cant think of any better idea here, except maybe move these to
respective board dts and perhaps keep them commented here for
documentation.

Do we have any better idea to solve this problem?

Thanks
-- 
~Vinod