Re: [PATCH 2/2] ASoC: atmel-classd: DT binding for Class D audio amplifier driver

From: Wu, Songjun
Date: Sun Sep 06 2015 - 05:44:56 EST

On 9/3/2015 19:43, Mark Brown wrote:
On Tue, Sep 01, 2015 at 01:41:41PM +0800, Songjun Wu wrote:

+classd: classd@fc048000 {
+ compatible = "atmel,sama5d2-classd";
+ reg = <0xfc048000 0x100>;
+ interrupts = <59 IRQ_TYPE_LEVEL_HIGH 7>;
+ dmas = <&dma0
+ | AT91_XDMAC_DT_PERID(47))>;
+ dma-names = "tx";
+ clocks = <&classd_clk>, <&classd_gclk>, <&audio_pll_pmc>;
+ clock-names = "pclk", "gclk", "aclk";
+ pinctrl-names = "default";
+ pinctrl-0 = <&pinctrl_classd_default>;
+ atmel,pwm-type = "diff";
+ atmel,non-overlap-time = <10>;

+sound {
+ compatible = "atmel,asoc-classd";
+ atmel,model = "classd @ SAMA5D2-Xplained";
+ atmel,audio-platform = <&classd>;
+ atmel,audio-cpu-dai-name = "fc048000.classd";
+ atmel,audio-codec = <&classd>;

Why is this a separate DT node? It seems that this IP is entirely self
contained so I'm not clear why we need a separate node for the card, the
card is usually a separate node because it ties together multiple
different devices in the system but that's not the case here.

The classD can finish the audio function without other devices.
But I want to reuse the code in ASoC, leave many things(like creating PCM, DMA operations) to ASoC, then the driver can only focus on how to configure classD.
The classD IP is divided to tree parts logically, platform, CPU dai,
and codec, and these parts are registered to ASoC.

This separate DT node is needed in ASoC, ties these tree parts in ClassD.

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