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 :)