Re: [PATCH] arm64: dts: mt8173: add clock_null
flat view
From: Daniel Kurtz <hidden>
Date: 2015-07-07 14:15:59
Also in:
linux-arm-kernel, linux-devicetree, lkml
On Tue, Jul 7, 2015 at 9:07 PM, Sascha Hauer [off-list ref] wrote:
On Thu, Jun 18, 2015 at 01:29:11PM +0800, Eddie Huang wrote:quoted
Add clk_null, which represents clocks that can not / need not controlled by software. There are many clocks' parent set to clk_null. Signed-off-by: James Liao <jamesjj.liao-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org> Signed-off-by: Eddie Huang <eddie.huang-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org> --- Base on 4.1-rc1 Change-Id: I4db9b40d07e28f54f7bae9b676316cbd6a962124 --- arch/arm64/boot/dts/mediatek/mt8173.dtsi | 6 ++++++ 1 file changed, 6 insertions(+)diff --git a/arch/arm64/boot/dts/mediatek/mt8173.dtsi b/arch/arm64/boot/dts/mediatek/mt8173.dtsi index 924fdb6..4798f44 100644 --- a/arch/arm64/boot/dts/mediatek/mt8173.dtsi +++ b/arch/arm64/boot/dts/mediatek/mt8173.dtsi@@ -81,6 +81,12 @@ cpu_on = <0x84000003>; }; + clk_null: clk_null { + compatible = "fixed-clock"; + clock-frequency = <0>; + #clock-cells = <0>; + };The discussion around this patch shows that we don't want to have this clock in the device tree as it is not a hardware description. Ok, fine. Eddie, you told us that the rate of the current clk_null children is not interesting. What's the motivation to send this patch anyway then? Why can't you keep its children on the orphan list where they are already now? Another possibility would be to instantiate the clk_null clock from C code rather than from the device tree. This way we wouldn't put any wrong descriptions into the device tree and still can implement the support for the real parent clocks when we actually need them.
Some device nodes, like mmc, use a clk_null phandle as one of their clocks:
mmc1: mmc@11240000 {
compatible = "mediatek,mt8173-mmc",
"mediatek,mt8135-mmc";
reg = <0 0x11240000 0 0x1000>;
interrupts = <GIC_SPI 72 IRQ_TYPE_LEVEL_LOW>;
clocks = <&pericfg CLK_PERI_MSDC30_1>,
<&clk_null>;
clock-names = "source", "hclk";
status = "disabled";
};
-Dan
Sascha -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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