From patchwork Fri Feb 17 12:41:51 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Claudiu Beznea X-Patchwork-Id: 13144662 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 0353DC636D4 for ; Fri, 17 Feb 2023 12:44:37 +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 1F07AF36; Fri, 17 Feb 2023 13:43:46 +0100 (CET) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa0.perex.cz 1F07AF36 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=alsa-project.org; s=default; t=1676637876; bh=Nd3sj2gVnzWEhmVAYlV1QIY3H4ahpeDxvqquOqfsu+c=; 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=k13oFQBh7zy9bRuhUy19SoCltH3PEsFUXUz5+/r2rbDypYwbm3YrjeZhM/5xnfDh0 TJPsRUgr5hW/sVHI3JHTB4jAfSlbEbuhzTlPGTG+DxQqN5kKEpzzB6ybpsCpl5gd7a PT1MPUoOgBYjRCkGMTHCEVEwNJ4G1cI8YD2aPiPk= Received: from mailman-core.alsa-project.org (mailman-core.alsa-project.org [10.254.200.10]) by alsa1.perex.cz (Postfix) with ESMTP id 6FB3BF80544; Fri, 17 Feb 2023 13:42:35 +0100 (CET) Received: by alsa1.perex.cz (Postfix, from userid 50401) id 3628EF80533; Fri, 17 Feb 2023 13:42:31 +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 03674F80171 for ; Fri, 17 Feb 2023 13:42:24 +0100 (CET) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa1.perex.cz 03674F80171 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=B0PxO4m4 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=microchip.com; i=@microchip.com; q=dns/txt; s=mchp; t=1676637746; x=1708173746; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=Nd3sj2gVnzWEhmVAYlV1QIY3H4ahpeDxvqquOqfsu+c=; b=B0PxO4m4Um6KBmc7fQc1mydw80TJYtk5GzOH9LjHPQ1BSbeiVz3wuiDD EeCGm9mDupaA+2RlhsZJIa++iyeWmpvM7tjn5HdZWXRRQKuKmBQuEg7zA XyZpVoF9vJ5U115f2SOr9q7At1fO/NT47ZRgSojkQlniaW8ycw0jUUvA8 FGoGZ9P8cQrIYoPTT054Vo6lxcXi6VzNYqmavoeAZCTyB4Gzbrixwu4VR 4A9E3M3BFKlOF70t8S7kAqkdGafcXwGAA8Sm0S3Uvj/3VlQNSvxdambwW SkYLlsCwJRWezcrGo9ca35QoDJEbDzMQ9sGbEvJX1ZoMMM/Yps81g/5M7 w==; X-IronPort-AV: E=Sophos;i="5.97,304,1669100400"; d="scan'208";a="201115103" Received: from unknown (HELO email.microchip.com) ([170.129.1.10]) by esa2.microchip.iphmx.com with ESMTP/TLS/AES256-SHA256; 17 Feb 2023 05:42:19 -0700 Received: from chn-vm-ex01.mchp-main.com (10.10.85.143) by chn-vm-ex03.mchp-main.com (10.10.85.151) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.16; Fri, 17 Feb 2023 05:42:18 -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; Fri, 17 Feb 2023 05:42:13 -0700 From: Claudiu Beznea To: , , , , , , , Subject: [PATCH v2 3/3] ASoC: mchp-pdmc: fix poc noise at capture startup Date: Fri, 17 Feb 2023 14:41:51 +0200 Message-ID: <20230217124151.236216-4-claudiu.beznea@microchip.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230217124151.236216-1-claudiu.beznea@microchip.com> References: <20230217124151.236216-1-claudiu.beznea@microchip.com> MIME-Version: 1.0 Message-ID-Hash: P3CW7U3ZF6N2U4N3ZNAYZ44OJLG6LLWZ X-Message-ID-Hash: P3CW7U3ZF6N2U4N3ZNAYZ44OJLG6LLWZ 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 --- Hi, Mark, If this is applied as is please add proper Depends-on tag to point to patch 1/3 commit id to ease the backporting on older kernels, if any. Thank you, Claudiu 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..6461e2741a33 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; @@ -425,6 +426,7 @@ static const struct snd_soc_component_driver mchp_pdmc_dai_component = { .open = &mchp_pdmc_open, .close = &mchp_pdmc_close, .legacy_dai_naming = 1, + .start_dma_last = 1, }; static const unsigned int mchp_pdmc_1mic[] = {1}; @@ -632,6 +634,29 @@ 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 +669,17 @@ 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 +823,7 @@ 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 +845,17 @@ 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 +875,7 @@ 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 +958,11 @@ 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; }