From 9ecad7f404b57d8a544c3211cf87a6284e49f4fd Mon Sep 17 00:00:00 2001 From: =?utf8?q?Uwe=20Kleine-K=C3=B6nig?= Date: Fri, 6 Dec 2024 18:28:34 +0100 Subject: [PATCH] iio: adc: ad7124: Refuse invalid input specifiers MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit The ad7124-4 has 8 analog inputs; the input select values 8 to 15 are reserved and not to be used. These are fine for ad7124-8. For both ad7124-4 and ad7124-8 values bigger than 15 are internal channels that might appear as inputs in the channels specified in the device description according to the description of commit f1794fd7bdf7 ("iio: adc: ad7124: Remove input number limitation"), values bigger than 31 don't fit into the respective register bit field and the driver masked them to smaller values. Check for these invalid input specifiers and fail to probe if one is found. Fixes: f1794fd7bdf7 ("iio: adc: ad7124: Remove input number limitation") Signed-off-by: Uwe Kleine-König Link: https://patch.msgid.link/80e3bd629d2b755ab5e061c8731dafa57d08698a.1733504533.git.u.kleine-koenig@baylibre.com Signed-off-by: Jonathan Cameron --- drivers/iio/adc/ad7124.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/drivers/iio/adc/ad7124.c b/drivers/iio/adc/ad7124.c index 7b749df9eeed8..b7491198e33c3 100644 --- a/drivers/iio/adc/ad7124.c +++ b/drivers/iio/adc/ad7124.c @@ -807,6 +807,19 @@ static int ad7124_check_chip_id(struct ad7124_state *st) return 0; } +/* + * Input specifiers 8 - 15 are explicitly reserved for ad7124-4 + * while they are fine for ad7124-8. Values above 31 don't fit + * into the register field and so are invalid for sure. + */ +static bool ad7124_valid_input_select(unsigned int ain, const struct ad7124_chip_info *info) +{ + if (ain >= info->num_inputs && ain < 16) + return false; + + return ain <= FIELD_MAX(AD7124_CHANNEL_AINM_MSK); +} + static int ad7124_parse_channel_config(struct iio_dev *indio_dev, struct device *dev) { @@ -859,6 +872,11 @@ static int ad7124_parse_channel_config(struct iio_dev *indio_dev, if (ret) return ret; + if (!ad7124_valid_input_select(ain[0], st->chip_info) || + !ad7124_valid_input_select(ain[1], st->chip_info)) + return dev_err_probe(dev, -EINVAL, + "diff-channels property of %pfwP contains invalid data\n", child); + st->channels[channel].nr = channel; st->channels[channel].ain = AD7124_CHANNEL_AINP(ain[0]) | AD7124_CHANNEL_AINM(ain[1]); -- 2.47.3