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

Icenowy Zheng
2016-08-01T15:02:22Z

01.08.2016, 21:40, "Chen-Yu Tsai" <wens@csie.org>:
> Hi,
>
> On Sat, Jul 30, 2016 at 11:20 PM, maxime.ripard at free-electrons.com
> <maxime.ripard@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