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Tue, 28 Apr 2026 08:54:04 -0700 (PDT) Received: from localhost.localdomain ([165.51.114.229]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-48a774c3ddfsm51036435e9.2.2026.04.28.08.54.01 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 28 Apr 2026 08:54:03 -0700 (PDT) From: Salah Triki To: Marcelo Schmitt , Jonathan Cameron , David Lechner , =?UTF-8?q?Nuno=20S=C3=A1?= , Andy Shevchenko Cc: linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org, Salah Triki Subject: [PATCH v2] iio: temperature: max30208: fix wrong scale value Date: Tue, 28 Apr 2026 16:53:49 +0100 Message-ID: <20260428155349.68019-1-salah.triki@gmail.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The driver currently returns a scale of 5 for IIO_CHAN_INFO_SCALE, which leads to incorrect temperature readings. According to the MAX30208 datasheet, the temperature resolution is 0.005°C per LSB. Using IIO_VAL_FRACTIONAL with 5/1000 correctly represents this 16-bit resolution. Although this is a change in the ABI, the current scale is objectively incorrect. A raw reading of 5000 (25°C) is currently reported as 25000°C, making the driver unusable with standard IIO tools. Given the magnitude of the error (factor of 1000) and the fact that the driver is relatively recent, fixing it to match the hardware specification is necessary. Fixes: 9ee95ae4cffd ("iio: temperature: Add driver support for Maxim MAX30208") Signed-off-by: Salah Triki --- Changes in v2: - Update commit message to justify the ABI change as requested by Andy. - Fix wrapping of the Fixes tag. drivers/iio/temperature/max30208.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/iio/temperature/max30208.c b/drivers/iio/temperature/max30208.c index 720469f9dc36..96f63c4fb2b6 100644 --- a/drivers/iio/temperature/max30208.c +++ b/drivers/iio/temperature/max30208.c @@ -163,7 +163,8 @@ static int max30208_read(struct iio_dev *indio_dev, case IIO_CHAN_INFO_SCALE: *val = 5; - return IIO_VAL_INT; + *val2 = 1000; + return IIO_VAL_FRACTIONAL; default: return -EINVAL; -- 2.43.0