From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4B59D155326 for ; Sun, 27 Jul 2025 21:06:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753650410; cv=none; b=XFz8jr/jvZa48S1WcponpxOdNmUVAa/Fb9UH9TCFS0DbUbXi0BQmKbuDHrExJF64OZASiI7SrPVffYEtlzhgXT07ENM+RMrRn6NsBNSjR6Ju7PDuGcCtB1xztIuV4NDSYvgp5JdwWFLi4TpnSrJ1VLdLz6XOr5E5CLXfA+hojrM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753650410; c=relaxed/simple; bh=aKB+dHHxOGmnbw6mlYRvcKnm7sSTei0qXryXjN/sKYU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=uRKrdVLm0toqjaIEi6Shqj25eanOEiO+xjx/+YZu9LRs0dDt3NUDT8zq7jXvHWreBVcxoMHILtMB/jlD0Y97ShQUEwbk8VJ1rCVq8QDRJAJNEnuLX5mOMEfAqVH/37zL2j95udS1F8ygsmdSZx2noDR97dtZXKe/vxoZnWJYDgQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=C/pmoCi7; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="C/pmoCi7" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7998AC4CEF7; Sun, 27 Jul 2025 21:06:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1753650409; bh=aKB+dHHxOGmnbw6mlYRvcKnm7sSTei0qXryXjN/sKYU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=C/pmoCi7PtexsWca1piRwoEQzMaSsbpfxX0AX5Jl2YMd6Ttg2+7bB2cILjlIxpnII jGBosa9M4Vhp2qxi4tDJGo6h0Bh8a/Jh63fQAnrrsJ2etnVaxLjGly7r1+M8xB35VC TzA7Q5+bCb4xAIDcz4dHPqCqS2lNk4Ugoc7CR5dFH20t1d66OIkhMNNL0PnYeuMSsk pOmE9ahqdfwTFl2SjjP4dkCRCCTzBG+eO/7qFyS9qVOcjv3mE/d7Hush7T7jmXVAHD pyJQIlYTSBOG4XJmUSLsKe+uXveif7m683qIRHdmXKrTrd7VHaBMVuoK0/8dVF1PJ2 1jUyLR6VUYfEQ== From: Hans de Goede To: Jonathan Cameron , David Lechner Cc: Hans de Goede , =?UTF-8?q?Nuno=20S=C3=A1?= , Andy Shevchenko , linux-iio@vger.kernel.org Subject: [PATCH v3 1/2] iio: Improve iio_read_channel_processed_scale() precision Date: Sun, 27 Jul 2025 23:06:38 +0200 Message-ID: <20250727210639.196351-2-hansg@kernel.org> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250727210639.196351-1-hansg@kernel.org> References: <20250727210639.196351-1-hansg@kernel.org> Precedence: bulk X-Mailing-List: linux-iio@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Before this change iio_read_channel_processed_scale() always assumes that channels which advertise IIO_CHAN_INFO_PROCESSED capability return IIO_VAL_INT on success. Ignoring any fractional values from drivers which return IIO_VAL_INT_PLUS_MICRO / IIO_VAL_INT_PLUS_NANO. These fractional values might become non fractional after scaling so these should be taken into account. While at it also error out for IIO_VAL_* values which iio_read_channel_processed_scale() does not know how to handle. Signed-off-by: Hans de Goede --- Changes in v3: - Use div_s64() instead of div_u64() to fix -1.0 - 0.0 range - Directly return IIO_VAL_INT from valid cases and drop the final return ret after the switch-case Changes in v2: - New patch in v2 of this patch-series --- drivers/iio/inkern.c | 24 ++++++++++++++++++++---- 1 file changed, 20 insertions(+), 4 deletions(-) diff --git a/drivers/iio/inkern.c b/drivers/iio/inkern.c index c174ebb7d5e6..46900be16ff8 100644 --- a/drivers/iio/inkern.c +++ b/drivers/iio/inkern.c @@ -714,20 +714,36 @@ int iio_read_channel_processed_scale(struct iio_channel *chan, int *val, unsigned int scale) { struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(chan->indio_dev); - int ret; + int ret, val2; guard(mutex)(&iio_dev_opaque->info_exist_lock); if (!chan->indio_dev->info) return -ENODEV; if (iio_channel_has_info(chan->channel, IIO_CHAN_INFO_PROCESSED)) { - ret = iio_channel_read(chan, val, NULL, + ret = iio_channel_read(chan, val, &val2, IIO_CHAN_INFO_PROCESSED); if (ret < 0) return ret; - *val *= scale; - return ret; + switch (ret) { + case IIO_VAL_INT: + *val *= scale; + return IIO_VAL_INT; + case IIO_VAL_INT_PLUS_MICRO: + *val *= scale; + *val += div_s64((s64)val2 * scale, 1000000LL); + return IIO_VAL_INT; + case IIO_VAL_INT_PLUS_NANO: + *val *= scale; + *val += div_s64((s64)val2 * scale, 1000000000LL); + return IIO_VAL_INT; + default: + dev_err_once(&chan->indio_dev->dev, + "unsupported processed IIO-val-type: %d\n", + ret); + return -EINVAL; + } } else { ret = iio_channel_read(chan, val, NULL, IIO_CHAN_INFO_RAW); if (ret < 0) -- 2.49.0