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SubjectRe: [PATCH v3 2/9] ASoC: rockchip: Remove obsolete dmic-delay
Hi Mark,

On 08/18/2017 07:52 PM, Mark Brown wrote:
> On Fri, Aug 18, 2017 at 09:41:54AM +0800, jeffy wrote:
>> On 08/18/2017 01:11 AM, Mark Brown wrote:
>>> On Thu, Aug 17, 2017 at 12:44:10PM +0800, Jeffy Chen wrote:
>
>>>> -Optional properties:
>>>> -- dmic-wakeup-delay-ms : specify delay time (ms) for DMIC ready.
>>>> - If this option is specified, which means it's required dmic need
>>>> - delay for DMIC to ready so that rt5514 can avoid recording before
>>>> - DMIC send valid data
>
>>> Why would nobody ever want to use this in future?
>
>> hmmm, check again, rt5514 fixed this issue in there driver instead in:
>> a5461fd6c8f7 ASoC: rt5514: Add the DMIC initial delay to wait it ready.
>
>> so we don't need this...
>
> You don't need it on your board for new DTs but why is it not possible
> that another board might need it?
>

this property is added in:
3a6f9dce6116 ASoC: rk3399_gru_sound: fix recording pop at first attempt

to fix pop noise by performing a delay after set dmic clk.

the binding said "dmic-wakeup-delay-ms", but actually driver parses
"dmic-delay":

+ /* Set DMIC delay */
+ ret = device_property_read_u32(&pdev->dev, "dmic-delay",
+ &rt5514_dmic_delay);

@@ -123,6 +125,9 @@ static int rockchip_sound_rt5514_hw_params(struct
snd_pcm_subst
ream *substream,
return ret;
}

+ /* Wait for DMIC stable */
+ msleep(rt5514_dmic_delay); <-- perform a delay after set dmic clk
+
return 0;
}

then realtek guys fixed this issue in the rt5514 codec driver:
a5461fd6c8f7 ASoC: rt5514: Add the DMIC initial delay to wait it ready.
+ device_property_read_u32(dev, "realtek,dmic-init-delay-ms",
+ &rt5514->pdata.dmic_init_delay);

@@ -452,6 +452,9 @@ static int rt5514_set_dmic_clk(struct
snd_soc_dapm_widget *w,
RT5514_CLK_DMIC_OUT_SEL_MASK,
idx << RT5514_CLK_DMIC_OUT_SEL_SFT);

+ if (rt5514->pdata.dmic_init_delay)
+ msleep(rt5514->pdata.dmic_init_delay); <-- perform a
delay after set dmic clk

so we don't need to deal with it in every boards' drivers which using
rt5514 codec, and we are using this new property now:
ag dmic arch/arm64/boot/dts/rockchip/rk3399-gru.dtsi
620: realtek,dmic-init-delay = <20>; <---- oops, seems
missing "-ms" at the end, guess due to realtek patch ends up differently
on upstream. will send a patch to fix it later.

anyway, i think it's ok to remove that out-dated property in our driver :)




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