Re: [PATCH v3 4/5] ARM: dts: sun9i: Add A80 PRCM clocks and reset control nodes

Jisheng Zhang
2015-11-24T10:27:09Z

+ Sebastian

On Tue, 24 Nov 2015 17:32:15 +0800
Chen-Yu Tsai wrote:

> This adds the supported PRCM clocks and reset controls to the A80 dtsi.
> The DAUDIO module clocks are not supported yet.
>
> Also update clock and reset phandles for r_uart.
>
> Signed-off-by: Chen-Yu Tsai <wens@csie.org>
> ---
> arch/arm/boot/dts/sun9i-a80.dtsi | 79 +++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 78 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm/boot/dts/sun9i-a80.dtsi b/arch/arm/boot/dts/sun9i-a80.dtsi
> index 1118bf5cc4fb..a4ce348c0831 100644
> --- a/arch/arm/boot/dts/sun9i-a80.dtsi
> +++ b/arch/arm/boot/dts/sun9i-a80.dtsi
> @@ -164,6 +164,14 @@
> "usb_phy2", "usb_hsic_12M";
> };
>
> + pll3: clk@06000008 {
> + /* placeholder until implemented */
> + #clock-cells = <0>;
> + compatible = "fixed-clock";
> + clock-rate = <0>;
> + clock-output-names = "pll3";
> + };
> +
> pll4: clk@0600000c {
> #clock-cells = <0>;
> compatible = "allwinner,sun9i-a80-pll4-clk";
> @@ -350,6 +358,68 @@
> "apb1_uart2", "apb1_uart3",
> "apb1_uart4", "apb1_uart5";
> };
> +
> + cpus_clk: clk@08001410 {
> + compatible = "allwinner,sun9i-a80-cpus-clk";
> + reg = <0x08001410 0x4>;
> + #clock-cells = <0>;
> + clocks = <&osc32k>, <&osc24M>, <&pll4>, <&pll3>;
> + clock-output-names = "cpus";
> + };
> +
> + ahbs: ahbs_clk {
> + compatible = "fixed-factor-clock";
> + #clock-cells = <0>;
> + clock-div = <1>;
> + clock-mult = <1>;
> + clocks = <&cpus_clk>;
> + clock-output-names = "ahbs";
> + };

Dear Sebastian and all,

I just want to take the sunxi clk support in mainline for example.

I'm not sure I understand correctly, it seems to me that some maintainers draw a
line: "having a node for every clock" is a no, no[1]. But here we saw one node for
cpus_clk and apbs below. And <0x08001410 0x4>; <0x0800141c 0x4>; shows they
are close each other, so should we merge them into a single clock complex node
then use mfd, regmap in clk driver?

But IMHO, sunxi dts nodes really represent real HW, so I still can't understand
why we could not have each node for cpus_clk and apbs. Can you please kindly
teach me?

Another question: is "Not having a node for every clock" a rule, Would you
please confirm? if yes, I'll strictly follow this rule.

[1]http://lists.infradead.org/pipermail/linux-arm-kernel/2015-November/387335.html

Thank you very much,
Jisheng

> +
> + apbs: clk@0800141c {
> + compatible = "allwinner,sun8i-a23-apb0-clk";
> + reg = <0x0800141c 0x4>;
> + #clock-cells = <0>;
> + clocks = <&ahbs>;
> + clock-output-names = "apbs";
> + };
> +
> + apbs_gates: clk@08001428 {
> + compatible = "allwinner,sun9i-a80-apbs-gates-clk";
> + reg = <0x08001428 0x4>;
> + #clock-cells = <1>;
> + clocks = <&apbs>;
> + clock-indices = <0>, <1>,
> + <2>, <3>,
> + <4>, <5>,
> + <6>, <7>,
> + <12>, <13>,
> + <16>, <17>,
> + <18>, <20>;
> + clock-output-names = "apbs_pio", "apbs_ir",
> + "apbs_timer", "apbs_rsb",
> + "apbs_uart", "apbs_1wire",
> + "apbs_i2c0", "apbs_i2c1",
> + "apbs_ps2_0", "apbs_ps2_1",
> + "apbs_dma", "apbs_i2s0",
> + "apbs_i2s1", "apbs_twd";
> + };

This is for gate clocks, so we have a node for gateclks. gateclks are merged
into one node.

> +
> + r_1wire_clk: clk@08001450 {
> + reg = <0x08001450 0x4>;
> + #clock-cells = <0>;
> + compatible = "allwinner,sun4i-a10-mod0-clk";
> + clocks = <&osc32k>, <&osc24M>;
> + clock-output-names = "r_1wire";
> + };
> +
> + r_ir_clk: clk@08001454 {
> + reg = <0x08001454 0x4>;
> + #clock-cells = <0>;
> + compatible = "allwinner,sun4i-a10-mod0-clk";
> + clocks = <&osc32k>, <&osc24M>;
> + clock-output-names = "r_ir";
> + };
> };
>
> soc {
> @@ -764,13 +834,20 @@
> interrupts = <GIC_SPI 36 IRQ_TYPE_LEVEL_HIGH>;
> };
>
> + apbs_rst: reset@080014b0 {
> + reg = <0x080014b0 0x4>;
> + compatible = "allwinner,sun6i-a31-clock-reset";
> + #reset-cells = <1>;
> + };
> +
> r_uart: serial@08002800 {
> compatible = "snps,dw-apb-uart";
> reg = <0x08002800 0x400>;
> interrupts = <GIC_SPI 38 IRQ_TYPE_LEVEL_HIGH>;
> reg-shift = <2>;
> reg-io-width = <4>;
> - clocks = <&osc24M>;
> + clocks = <&apbs_gates 4>;
> + resets = <&apbs_rst 4>;
> status = "disabled";
> };
> };