From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-vs1-f53.google.com (mail-vs1-f53.google.com [209.85.217.53]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 571063C1F57 for ; Fri, 28 Aug 2026 06:38:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.217.53 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787899134; cv=none; b=uFLB2LDEzso7qKRAuJBY4T5JEubQ03aLQOtMUUkcbKJ6bYSwFRCqYJE/XzpaCNS4UqvKChGGHTXlIzeOxD2uzjHv/g+KfrsNmmwTf5tHJuSOdF7vx1CEEs5Llua0zM8acu40/WpPXdZAAMUko87+5L0VvTVarfKSkVdyHK3g7A0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787899134; c=relaxed/simple; bh=jBnuNfFaNy+lYevkOT79mOgADpfoXMW0c9FuXIA5WWY=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=Fio9YsdLzzV+Kj+k24ZLikDvDZ6Cq184uIwZAkrAJAzPVoPEya0J1hMxLS+oEt1vmDtW/W5dkvDahP8IYyMnzpcnW473swkNQZy6qILdSY375DTwoUjOKWxSw1LZij6sEuqxIIZg6GdDU9CdFuhOvVYTZhgsmqXbS+Ki7jAlCIA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=G5miVteJ; arc=none smtp.client-ip=209.85.217.53 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="G5miVteJ" Received: by mail-vs1-f53.google.com with SMTP id ada2fe7eead31-783d429d0cfso383177137.3 for ; Thu, 27 Aug 2026 23:38:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1787899131; x=1788503931; darn=vger.kernel.org; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :content-type:mime-version:subject:date:from:from:to:cc:subject:date :message-id:reply-to:content-type; bh=hcOlTatZtiMtegG+sIDHWIx8wVSL0Q7Xb7hEFQvq7zQ=; b=G5miVteJq064cTyZyjT0ACmOINFtxxWOrOPD8enRbI/Oly1Id0MZSKc9YHys0OR1Dg QQe95gpoTfCtfdOdSRsFY/xzO3Msk9S5ATNbs08ZN24lTVz9xPcjHFoZLhWfRSZsSVC7 xX+QR1TlrQIPXAbS/9nXaVpkqX2y0OuOrSCovOLGTri6SLpT3zPpqs52+SPuQn80YMF0 OX4OAEcaH8xKAolyll+jIoK/iNcglL5MFhWezkrneoJlYQe4JLQV3+XyNnHGjHeJ1gYt dEzQ32i9In3GTU91f6tHRTA7HdAHQHHJTwrMYUMcheWACshlF+2QLQOLBxbu5yUyg3zu FX5A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1787899131; x=1788503931; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :content-type:mime-version:subject:date:from:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=hcOlTatZtiMtegG+sIDHWIx8wVSL0Q7Xb7hEFQvq7zQ=; b=EHD9gAz2cD1vPQoCXn9ioMhbWyLrWDsI8Xs7ypW/CAL1sBTpRN3OCEzaVlG6GZukCU UN1bILZgniXMIIfdGE8UmERd7wzF/aPALEE6q2n2eXClZxYN5IasEuz3KSNDyVBTe1if QaCrhy2QZIzPKG+wVOKykLlBh1NzKzu6SQTbFXaTxyAarxs/2r4+8ZWBbR68EgkGzLHt 0LA5D9EyTPRD4FVMTC8wqIfWEBbuIlSiFX2qHIhRu42qOUzW2ZesdZTZp9yfFQXaaDRx KBelVgAIWcKdUL5X1teeMswOsMoH8Ow2fAiWOCEiAjFj1uU0NyisINB14zz31Q8J/NK/ ox0Q== X-Forwarded-Encrypted: i=1; AHgh+Rqb3SIEKrt4TGv32oLa4cdGdY0SRVlcO4ja6bVfCK9y5MMU4hRHBAONlF6gP6xQIoLx3qaH/+VyWuGM@vger.kernel.org X-Gm-Message-State: AFuF++mvKnMfNK+wrva69PMCKLNmCbRzCtv9Qn1uEyzDNrKR+ZOzGWGW OfCnAus2ljaMPL3IL61crm14F526681GFXPS8dzx10EbRWTO1gHz45qmoRdKiQ== X-Gm-Gg: AR+sD135L4dSNdjbS2+dP06nqwy8XqyDhEDz1cZl/gZ1bysWvph4B2NFAWX3bLRgqbj xTaRh+/d1iO1mX9QxVGNz9Ck6rsy9KKLBgMIHHXT9E6vuMqxM1gcX/iyQzyBQY87LG+pkeT4AI9 h2i2TuYpVQPKrKRE7B/iNVS17JEFaPpyqXq7VZ4CBtTUIkQyblYjLYuveZuUTfGW8AAxbe42Kxe g5hP/b1kdSluznvYuWCvO0O8ImS22L09Pfkx/1Vy1ypA2pjFsr19IOUW8EZTUcB7J1sTepncP4R F1ImuK2YXag30DUHsME2h7aBFth9Iq/YfbW1NfCy6hwIvhwCvhVS4+MNbTBzdzHWT7jglFwQwqy 7xvw7nXA5pSawwT2wuORuCZSBma2uYhRVzp5UoytQYXRAxQRnNCBApDzp8CdXkhzy5nc+GpJV6W sF/bWX9Nuv7dir5LjCEcPpKMx1fw2/USFpJLfu1tkkP7oOQqeQOMgyfzR7lQTxq55U X-Received: by 2002:a05:6102:3e83:b0:779:c38e:de53 with SMTP id ada2fe7eead31-7859956a1cdmr1778891137.10.1787899131018; Thu, 27 Aug 2026 23:38:51 -0700 (PDT) Received: from [192.168.100.153] ([2800:bf0:61:1127:ab87:5602:531c:8dfb]) by smtp.gmail.com with ESMTPSA id a1e0cc1a2514c-97e849d8494sm454195241.1.2026.08.27.23.38.49 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 27 Aug 2026 23:38:50 -0700 (PDT) From: Kurt Borja Date: Fri, 28 Aug 2026 01:38:21 -0500 Subject: [PATCH v4 06/10] iio: adc: ti-ads1262: support input chopping Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260828-ads126x-v4-6-1dc27e9c0260@gmail.com> References: <20260828-ads126x-v4-0-1dc27e9c0260@gmail.com> In-Reply-To: <20260828-ads126x-v4-0-1dc27e9c0260@gmail.com> To: Kurt Borja , Jonathan Cameron , Rob Herring , Krzysztof Kozlowski , Conor Dooley , David Lechner Cc: =?utf-8?q?Nuno_S=C3=A1?= , Andy Shevchenko , linux-iio@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org X-Mailer: b4 0.15.2 X-Developer-Signature: v=1; a=openpgp-sha256; l=3240; i=kuurtb@gmail.com; h=from:subject:message-id; bh=jBnuNfFaNy+lYevkOT79mOgADpfoXMW0c9FuXIA5WWY=; b=owGbwMvMwCUmluBs8WX+lTTG02pJDFkTdd6031zRuqLFyVz66v4vesfMzvmHhlYFRc2PkQ7Ly pryj/l4RykLgxgXg6yYIkt7wqJvj6Ly3vodCL0PM4eVCWQIAxenAExk5SuGf7YGAqskZljs+Kzg ZNu/78XZ7yuez/ivru6knPoiZ8Nv7xRGhi4NvWU2zmWppzu/WkibqggtfcjgG7Ca90oxe9FJQ6N 8LgA= X-Developer-Key: i=kuurtb@gmail.com; a=openpgp; fpr=54D3BE170AEF777983C3C63B57E3B6585920A69A Enable per-channel input chopping via the "input-chopping" property. As the device withholds the first conversion in chop mode, single reads are taken in CONTINUOUS run mode with a brief start/stop pulse, as recommended by the datasheet (Section 9.4.1.2). Reviewed-by: David Lechner Signed-off-by: Kurt Borja --- drivers/iio/adc/ti-ads1262.c | 25 +++++++++++++++++++++---- 1 file changed, 21 insertions(+), 4 deletions(-) diff --git a/drivers/iio/adc/ti-ads1262.c b/drivers/iio/adc/ti-ads1262.c index c87c0a66119a..4d38da092001 100644 --- a/drivers/iio/adc/ti-ads1262.c +++ b/drivers/iio/adc/ti-ads1262.c @@ -203,6 +203,7 @@ struct ads1262_channel { u8 ref_n; bool ref_reversal; bool is_resistance; + bool input_chop; size_t num_scales; int scales[ADS1262_GAIN_COUNT][2]; }; @@ -464,7 +465,7 @@ static int ads1262_dev_stop(struct ads1262 *st) return ret; } -static int ads1262_dev_start_one(struct ads1262 *st) +static int ads1262_dev_start_one(struct ads1262 *st, u8 runmode) { int ret; @@ -472,7 +473,7 @@ static int ads1262_dev_start_one(struct ads1262 *st) if (ret) return ret; - if (st->start_gpiod) { + if (runmode == ADS1262_RUNMODE_CONTINUOUS || st->start_gpiod) { /* * The START pulse timing requirement is 4 clock cycles, at the * minimum clock rate this is 4 microseconds. @@ -520,7 +521,9 @@ static int ads1262_channel_enable(struct ads1262 *st, guard(mutex)(&st->chan_lock); ret = regmap_update_bits(st->regmap, ADS1262_MODE0_REG, + ADS1262_MODE0_INPUT_CHOP_MASK | ADS1262_MODE0_REFREV_MASK, + FIELD_PREP(ADS1262_MODE0_INPUT_CHOP_MASK, chan->input_chop) | FIELD_PREP(ADS1262_MODE0_REFREV_MASK, chan->ref_reversal)); if (ret) return ret; @@ -561,13 +564,26 @@ static int ads1262_channel_read(struct iio_dev *indio_dev, const struct iio_chan_spec *spec, __be32 *val) { struct ads1262 *st = iio_priv(indio_dev); + struct ads1262_channel *chan = &st->channels[spec->scan_index]; + u8 runmode; int ret; IIO_DEV_ACQUIRE_DIRECT_MODE(indio_dev, claim); if (IIO_DEV_ACQUIRE_FAILED(claim)) return -EBUSY; - ret = ads1262_set_runmode(st, ADS1262_RUNMODE_PULSE); + /* + * When a channel has chop mode or IDAC rotation mode, the first + * conversion is always withheld so the datasheet suggests using the + * CONTINUOUS mode and briefly starting and stopping conversions to + * achieve the same effect (Section 9.4.1.2). + */ + if (chan->input_chop) + runmode = ADS1262_RUNMODE_CONTINUOUS; + else + runmode = ADS1262_RUNMODE_PULSE; + + ret = ads1262_set_runmode(st, runmode); if (ret) return ret; @@ -577,7 +593,7 @@ static int ads1262_channel_read(struct iio_dev *indio_dev, reinit_completion(&st->drdy); - ret = ads1262_dev_start_one(st); + ret = ads1262_dev_start_one(st, runmode); if (ret) return ret; @@ -1340,6 +1356,7 @@ static int ads1262_parse_channel_node(struct ads1262 *st, } } + chan->input_chop = fwnode_property_read_bool(node, "input-chopping"); chan->ref_reversal = fwnode_property_read_bool(node, "ti,reference-reversal"); return 0; -- 2.55.0