[alsa-devel] [linux-sunxi] Re: [PATCH 2/2] ASoC: sunxi: compatibility for sun6i to SPDIF

[Icenowy Zheng]

01.08.2016, 21:40, "Chen-Yu Tsai" <wens at csie.org>:
> Hi,
>
> On Sat, Jul 30, 2016 at 11:20 PM, maxime.ripard at free-electrons.com
> <maxime.ripard at free-electrons.com> wrote:
>>  On Sat, Jul 30, 2016 at 10:52:45PM +0800, Icenowy Zheng wrote:
>>>  > + if (of_device_is_compatible(pdev->dev.of_node,
>>>  > + "allwinner,sun6i-a31-spdif")) {
>>>  > + host->rst = devm_reset_control_get_optional(&pdev->dev, NULL);
>>>  > + if (IS_ERR(host->rst) && PTR_ERR(host->rst) == -EPROBE_DEFER) {
>>>  > + ret = -EPROBE_DEFER;
>>>  > + dev_err(&pdev->dev, "Failed to get reset: %d\n", ret);
>>>  > + goto err_disable_apb_clk;
>>>  > + }
>>>  > + if (!IS_ERR(host->rst))
>>>  > + reset_control_deassert(host->rst);
>>>  > + }
>>>  > +
>>>  I think you do not need the compatible.
>>>  You can just detect whether the reset is present.
>>
>>  That would weaken the error check. If we're running on the A31 and are
>>  missing our reset property, it would go unnoticed.
>
> We've been doing it this way with the mmc controller and the usb hosts though.
I did the same thing on NAND controller.
> IIRC you once said in the older SoCs, the reset control is tied to the clock
> gate in the hardware.
>
> The _optional variant is also funny, though I understand it is a design
> of the reset controller framework.
>
> Regards
> ChenYu