From patchwork Tue Feb 14 16:14:35 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Claudiu Beznea X-Patchwork-Id: 654115 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from alsa0.perex.cz (alsa0.perex.cz [77.48.224.243]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id E0D6FC61DA4 for ; Tue, 14 Feb 2023 16:19:24 +0000 (UTC) Received: from alsa1.perex.cz (alsa1.perex.cz [207.180.221.201]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by alsa0.perex.cz (Postfix) with ESMTPS id 67E34DF0; Tue, 14 Feb 2023 17:18:32 +0100 (CET) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa0.perex.cz 67E34DF0 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=alsa-project.org; s=default; t=1676391562; bh=uALPcs3Vx7BPrxo0UgAKw4uy0dcv8BW3De7tw3ZgiME=; h=From:To:Subject:Date:In-Reply-To:References:CC:List-Id: List-Archive:List-Help:List-Owner:List-Post:List-Subscribe: List-Unsubscribe:From; b=dS0U4qYSwQFBV0WYAYGvYKQ3rc5mSre8dHENZ51QLorBIp+KNuTjwEZUoVq4DU0XL 62QjjVLAKqJ6P5t0iok3k8cf7AitN95K7ECSnYAoe6VYGtwL7O0Q2g91jjvO5yelIY H66kzzAZJWim6cFSf/SuTmfKOHa/cNMoW9F377IQ= Received: from mailman-core.alsa-project.org (mailman-core.alsa-project.org [10.254.200.10]) by alsa1.perex.cz (Postfix) with ESMTP id B212EF80549; Tue, 14 Feb 2023 17:17:33 +0100 (CET) Received: by alsa1.perex.cz (Postfix, from userid 50401) id B109EF80549; Tue, 14 Feb 2023 17:17:29 +0100 (CET) Received: from esa.microchip.iphmx.com (esa.microchip.iphmx.com [68.232.154.123]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by alsa1.perex.cz (Postfix) with ESMTPS id 5C10AF804B0 for ; Tue, 14 Feb 2023 17:17:21 +0100 (CET) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa1.perex.cz 5C10AF804B0 Authentication-Results: alsa1.perex.cz; dkim=pass (2048-bit key, unprotected) header.d=microchip.com header.i=@microchip.com header.a=rsa-sha256 header.s=mchp header.b=x8jJHrX+ DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=microchip.com; i=@microchip.com; q=dns/txt; s=mchp; t=1676391443; x=1707927443; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=uALPcs3Vx7BPrxo0UgAKw4uy0dcv8BW3De7tw3ZgiME=; b=x8jJHrX+V8o1jIborvrTBaJ/K9lySotwz7cOb2vpl9rIqpcfiBkilSS7 zm+B6aaQdN2Bz3ZanysV0egB2Hq3gE0KiMg5BOqX9w5ffQIEepn4rFcDH Yw3LvGXNEwCkQO0MokpEDAuxPNuzk2rd2EEgWy/+6E9DEKiF8j8JCygGy XRZzcMYe3mrl9TF4euRaEW+6X83mpiXxhxKok23sQ200sWPZnTSvHoMXi /5vs3En1PFPTFtQ6fElh7/VOuuRJpheRi/TQVvxT+W2DMo7wwcfunZ9IN PPa6QU0LQVykdQ42XO+xfhC7ZKq9ncB0eko4gWzKU7bUpiFvYh50IL/Xa w==; X-IronPort-AV: E=Sophos;i="5.97,297,1669100400"; d="scan'208";a="196891478" Received: from unknown (HELO email.microchip.com) ([170.129.1.10]) by esa4.microchip.iphmx.com with ESMTP/TLS/AES256-SHA256; 14 Feb 2023 09:17:19 -0700 Received: from chn-vm-ex01.mchp-main.com (10.10.85.143) by chn-vm-ex02.mchp-main.com (10.10.85.144) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.16; Tue, 14 Feb 2023 09:17:07 -0700 Received: from m18063-ThinkPad-T460p.mchp-main.com (10.10.115.15) by chn-vm-ex01.mchp-main.com (10.10.85.143) with Microsoft SMTP Server id 15.1.2507.16 via Frontend Transport; Tue, 14 Feb 2023 09:17:03 -0700 From: Claudiu Beznea To: , , , , , , , , Subject: [PATCH 3/3] ASoC: mchp-pdmc: fix poc noise at capture startup Date: Tue, 14 Feb 2023 18:14:35 +0200 Message-ID: <20230214161435.1088246-4-claudiu.beznea@microchip.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230214161435.1088246-1-claudiu.beznea@microchip.com> References: <20230214161435.1088246-1-claudiu.beznea@microchip.com> MIME-Version: 1.0 Message-ID-Hash: 3KZVPP6PFAWCKGLH4CYLLU4ETKALN2UD X-Message-ID-Hash: 3KZVPP6PFAWCKGLH4CYLLU4ETKALN2UD X-MailFrom: Claudiu.Beznea@microchip.com X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; header-match-alsa-devel.alsa-project.org-0; header-match-alsa-devel.alsa-project.org-1; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header CC: alsa-devel@alsa-project.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Claudiu Beznea X-Mailman-Version: 3.3.8 Precedence: list List-Id: "Alsa-devel mailing list for ALSA developers - http://www.alsa-project.org" Archived-At: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: Microchip PDMC IP doesn't filter microphone noises on startup. By default, it captures data received from digital microphones after the MCHP_PDMC_MR.EN bits are set. Thus when enable is set on PDMC side the digital microphones might not be ready yet and PDMC captures data from then in this time. This data captured is poc noise. To avoid this the software workaround is to the following: 1/ enable PDMC channel 2/ wait 150ms (on SAMA7G5-EK setup) 3/ execute 16 dummy reads from RHR 4/ clear interrupts 5/ enable interrupts 6/ enable DMA channel Fixes: 50291652af52 ("ASoC: atmel: mchp-pdmc: add PDMC driver") Signed-off-by: Claudiu Beznea --- sound/soc/atmel/mchp-pdmc.c | 55 +++++++++++++++++++++++++++++++++---- 1 file changed, 50 insertions(+), 5 deletions(-) diff --git a/sound/soc/atmel/mchp-pdmc.c b/sound/soc/atmel/mchp-pdmc.c index cf4084dcbd5e..c5f597ebfa47 100644 --- a/sound/soc/atmel/mchp-pdmc.c +++ b/sound/soc/atmel/mchp-pdmc.c @@ -114,6 +114,7 @@ struct mchp_pdmc { struct clk *gclk; u32 pdmcen; u32 suspend_irq; + u32 startup_delay_us; int mic_no; int sinc_order; bool audio_filter_en; @@ -632,6 +633,29 @@ static int mchp_pdmc_hw_params(struct snd_pcm_substream *substream, return 0; } +static void mchp_pdmc_noise_filter_workaround(struct mchp_pdmc *dd) +{ + u32 tmp, steps = 16; + + /* + * PDMC doesn't wait for microphones' startup time thus the acquisition + * may start before the microphones are ready leading to poc noises at + * the beginning of capture. To avoid this, we need to wait 50ms (in + * normal startup procedure) or 150 ms (worst case after resume from sleep + * states) after microphones are enabled and then clear the FIFOs (by + * reading the RHR 16 times) and possible interrupts before continuing. + * Also, for this to work the DMA needs to be started after interrupts + * are enabled. + */ + usleep_range(dd->startup_delay_us, dd->startup_delay_us + 5); + + while (steps--) + regmap_read(dd->regmap, MCHP_PDMC_RHR, &tmp); + + /* Clear interrupts. */ + regmap_read(dd->regmap, MCHP_PDMC_ISR, &tmp); +} + static int mchp_pdmc_trigger(struct snd_pcm_substream *substream, int cmd, struct snd_soc_dai *dai) { @@ -644,15 +668,17 @@ static int mchp_pdmc_trigger(struct snd_pcm_substream *substream, switch (cmd) { case SNDRV_PCM_TRIGGER_RESUME: case SNDRV_PCM_TRIGGER_START: - /* Enable overrun and underrun error interrupts */ - regmap_write(dd->regmap, MCHP_PDMC_IER, dd->suspend_irq | - MCHP_PDMC_IR_RXOVR | MCHP_PDMC_IR_RXUDR); - dd->suspend_irq = 0; - fallthrough; case SNDRV_PCM_TRIGGER_PAUSE_RELEASE: snd_soc_component_update_bits(cpu, MCHP_PDMC_MR, MCHP_PDMC_MR_PDMCEN_MASK, dd->pdmcen); + + mchp_pdmc_noise_filter_workaround(dd); + + /* Enable interrupts. */ + regmap_write(dd->regmap, MCHP_PDMC_IER, dd->suspend_irq | + MCHP_PDMC_IR_RXOVR | MCHP_PDMC_IR_RXUDR); + dd->suspend_irq = 0; break; case SNDRV_PCM_TRIGGER_SUSPEND: regmap_read(dd->regmap, MCHP_PDMC_IMR, &dd->suspend_irq); @@ -796,6 +822,7 @@ static bool mchp_pdmc_readable_reg(struct device *dev, unsigned int reg) case MCHP_PDMC_CFGR: case MCHP_PDMC_IMR: case MCHP_PDMC_ISR: + case MCHP_PDMC_RHR: case MCHP_PDMC_VER: return true; default: @@ -817,6 +844,17 @@ static bool mchp_pdmc_writeable_reg(struct device *dev, unsigned int reg) } } +static bool mchp_pdmc_volatile_reg(struct device *dev, unsigned int reg) +{ + switch (reg) { + case MCHP_PDMC_ISR: + case MCHP_PDMC_RHR: + return true; + default: + return false; + } +} + static bool mchp_pdmc_precious_reg(struct device *dev, unsigned int reg) { switch (reg) { @@ -836,6 +874,7 @@ static const struct regmap_config mchp_pdmc_regmap_config = { .readable_reg = mchp_pdmc_readable_reg, .writeable_reg = mchp_pdmc_writeable_reg, .precious_reg = mchp_pdmc_precious_reg, + .volatile_reg = mchp_pdmc_volatile_reg, .cache_type = REGCACHE_FLAT, }; @@ -918,6 +957,11 @@ static int mchp_pdmc_dt_init(struct mchp_pdmc *dd) dd->channel_mic_map[i].clk_edge = edge; } + ret = of_property_read_u32(np, "microchip,startup-delay-us", + &dd->startup_delay_us); + if (ret) + dd->startup_delay_us = 150000; + return 0; } @@ -941,6 +985,7 @@ static int mchp_pdmc_process(struct snd_pcm_substream *substream, static struct snd_dmaengine_pcm_config mchp_pdmc_config = { .process = mchp_pdmc_process, .prepare_slave_config = snd_dmaengine_pcm_prepare_slave_config, + .start_dma_last = 1, }; static int mchp_pdmc_runtime_suspend(struct device *dev)