From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1423140AbeBPCrf (ORCPT ); Thu, 15 Feb 2018 21:47:35 -0500 Received: from mail-it0-f66.google.com ([209.85.214.66]:34891 "EHLO mail-it0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1423102AbeBPCrd (ORCPT ); Thu, 15 Feb 2018 21:47:33 -0500 X-Google-Smtp-Source: AH8x226PWCPvUG080ReMlvREErvOVwKnMcBVNAQYBXJRXEGZjNDKuf3TILqIdwcEDTeN5gQ7kqMpCg== Date: Thu, 15 Feb 2018 18:47:29 -0800 From: Brian Norris To: Matthias Kaehlcke Cc: Liam Girdwood , Mark Brown , Rob Herring , Mark Rutland , Jaroslav Kysela , Takashi Iwai , Peter Ujfalusi , alsa-devel@alsa-project.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, Dylan Reid , huang lin Subject: Re: [PATCH v2] ASoC: dmic: Add optional wakeup delay Message-ID: <20180216024728.GA93733@rodete-desktop-imager.corp.google.com> References: <20180216022416.208265-1-mka@chromium.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180216022416.208265-1-mka@chromium.org> User-Agent: Mutt/1.9.2 (2017-12-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On Thu, Feb 15, 2018 at 06:24:16PM -0800, Matthias Kaehlcke wrote: > On some systems a delay is needed after switching on the clocks, to allow > the output to stabilize and avoid a popping noise at the beginning of > the recording. Add the optional device tree property 'wakeup-delay-ms' > and apply the specified delay after enabling the mic. A blocking delay > can't be applied in dmic_daiops_trigger() since the function is called > in atomic context. Instead use a DAPM event handler to set the enable > GPIO and apply the delay in the handler. > > Signed-off-by: Matthias Kaehlcke > --- > Changes in v2: > - use DAPM event handler instead of _prepare() and get rid of > _trigger() > - skip error check for optional 'wakeup-delay-ms' property > - updated commit message Looks good to me in general: Brian Norris But I don't know much about the audio subsystem. One comment below. > > .../devicetree/bindings/sound/dmic.txt | 2 + > sound/soc/codecs/dmic.c | 63 ++++++++++--------- > 2 files changed, 37 insertions(+), 28 deletions(-) > > diff --git a/Documentation/devicetree/bindings/sound/dmic.txt b/Documentation/devicetree/bindings/sound/dmic.txt > index f7bf65611453..e957b4136716 100644 > --- a/Documentation/devicetree/bindings/sound/dmic.txt > +++ b/Documentation/devicetree/bindings/sound/dmic.txt > @@ -8,6 +8,7 @@ Required properties: > Optional properties: > - dmicen-gpios: GPIO specifier for dmic to control start and stop > - num-channels: Number of microphones on this DAI > + - wakeup-delay-ms: Delay (in ms) after enabling the DMIC > > Example node: > > @@ -15,4 +16,5 @@ Example node: > compatible = "dmic-codec"; > dmicen-gpios = <&gpio4 3 GPIO_ACTIVE_HIGH>; > num-channels = <1>; > + wakeup-delay-ms <50>; > }; > diff --git a/sound/soc/codecs/dmic.c b/sound/soc/codecs/dmic.c > index cf83c423394d..b5f60ac22ace 100644 > --- a/sound/soc/codecs/dmic.c > +++ b/sound/soc/codecs/dmic.c [...] > static const struct snd_soc_dapm_widget dmic_dapm_widgets[] = { > - SND_SOC_DAPM_AIF_OUT("DMIC AIF", "Capture", 0, > - SND_SOC_NOPM, 0, 0), > + SND_SOC_DAPM_AIF_OUT_E("DMIC AIF", "Capture", 0, > + SND_SOC_NOPM, 0, 0, dmic_aif_event, > + SND_SOC_DAPM_POST_PMU | SND_SOC_DAPM_POST_PMD), Any good reason both are _POST_? It seems like you'd want them to be inverses (e.g., power-power-up, and pre-power-down). > SND_SOC_DAPM_INPUT("DMic"), > }; > Brian