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 5F8831FE100; Thu, 24 Oct 2024 17:42:53 +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=1729791773; cv=none; b=rw9ocUNFcbXUcllxLWU2HDGsIcpTCA9L0F+0OmLBOlgJMgjK/mn89qAdas6BOZ+55M7YUpY0x+QfaOLvl2mhPzi0FS+OHb+MTLCEw8175BzO8XED6ez7DY+lbiGx/fd/a13PuwsKm1/sI5S+0YnnvXly+q4mbCYbKZmP6iUJXJ8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729791773; c=relaxed/simple; bh=rgwkQHONl3k5lKfdipk3SO5F9eAWZNlyVIfQ29lbZsY=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=VVb3BiNYNukdTp/LykjI6/ZSe2C/Vp+a1yqd/nsc6zyU/IL8+xI60u0E5USm8h03UZElJ8inlXCeTRYkTymm2Aevy4iq+D58/S5BKfi7HpCkSH5SURFIREbbnR8x2JSf6vp8+OZfjRB+EpK75pbPZ5aysEisWao2QaMHSmLmQek= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Z4BXJJT3; 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="Z4BXJJT3" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 816EFC4CEC7; Thu, 24 Oct 2024 17:42:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1729791772; bh=rgwkQHONl3k5lKfdipk3SO5F9eAWZNlyVIfQ29lbZsY=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=Z4BXJJT3aWuRhvYRTkGPI59Apy2sdoSkVAv5dFPSmEO8LO8SXDsNQFFyh8gRe4uK3 LZEqv1nNXcUn1BimMR7XxSCOUj3R4HLfWkFreNu6O9An5WtWVrJGkQ0R7Sc1fJ0lJf hvocUfCtPb7MNFwwKbzQMWzVHJmHJOjv5YuZNESW96EsOE3EssZ+MsGYV4BCuW3slA DoxW/TLUE+oFevwzmJIMCSjocAmRpiGEKe7RMwBgtQjtdLCmpKCpqRDBeDyKsFXT8V pAuUhY3SigID/oDsLyHmlhOrhDijOI4MjN/jhpPXR6bvjiFN9RHzzMIHyDn9LQHSvZ cJPwEecvAvtew== Date: Thu, 24 Oct 2024 18:42:45 +0100 From: Jonathan Cameron To: Javier Carrasco Cc: Lars-Peter Clausen , Rishi Gupta , Jonathan Cameron , linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH] iio: light: veml6030: fix microlux value calculation Message-ID: <20241024184245.29374611@jic23-huawei> In-Reply-To: <20241019153359.43f0c1af@jic23-huawei> References: <20241016-veml6030-fix-processed-micro-v1-1-4a5644796437@gmail.com> <20241019153359.43f0c1af@jic23-huawei> X-Mailer: Claws Mail 4.3.0 (GTK 3.24.43; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Sat, 19 Oct 2024 15:33:59 +0100 Jonathan Cameron wrote: > On Wed, 16 Oct 2024 19:04:31 +0200 > Javier Carrasco wrote: > > > The raw value conversion to obtain a measurement in lux as > > INT_PLUS_MICRO does not calculate the decimal part properly to display > > it as micro (in this case microlux). It only calculates the module to > > obtain the decimal part from a resolution that is 10000 times the > > provided in the datasheet (0.5376 lux/cnt for the veml6030). The > > resulting value must still be multiplied by 100 to make it micro. > > > > This bug was introduced with the original implementation of the driver. > > > > Cc: stable@vger.kernel.org > > Fixes: 7b779f573c48 ("iio: light: add driver for veml6030 ambient light sensor") > > Signed-off-by: Javier Carrasco > Applied to the fixes-togreg branch of iio.git. As per the linux-next merge conflict email that I've just +CC linux-iio on, I messed this up and it landed on the wrong code block. Tried again... Jonathan > > Thanks, > > Jonathan > > > --- > > I found this almost by chance while testing new supported devices. The > > decimal part was always suspiciously small, and when I compared samples > > to the expected value according to the datasheet, it became clear what was > > going on. > > > > Example with a veml7700 (same resolution as the veml6030): > > > > Resolution for gain = 1/8, IT = 100 ms: 0.5736 lux/cnt. > > > > cat in_illuminance_raw in_illuminance_input > > 40 > > 21.005040 -> wrong! 40 * 0.5736 is 21.504. > > > > Tested with a veml6035 and a veml7700, the same will happen with the > > original veml6030, as the operation is identical for all devices. > > --- > > drivers/iio/light/veml6030.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/drivers/iio/light/veml6030.c b/drivers/iio/light/veml6030.c > > index d6f3b104b0e6..a0bf03e37df7 100644 > > --- a/drivers/iio/light/veml6030.c > > +++ b/drivers/iio/light/veml6030.c > > @@ -691,7 +691,7 @@ static int veml6030_read_raw(struct iio_dev *indio_dev, > > } > > if (mask == IIO_CHAN_INFO_PROCESSED) { > > *val = (reg * data->cur_resolution) / 10000; > > - *val2 = (reg * data->cur_resolution) % 10000; > > + *val2 = (reg * data->cur_resolution) % 10000 * 100; > > return IIO_VAL_INT_PLUS_MICRO; > > } > > *val = reg; > > > > --- > > base-commit: 15e7d45e786a62a211dd0098fee7c57f84f8c681 > > change-id: 20241016-veml6030-fix-processed-micro-616d00d555dc > > > > Best regards, > >