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([2600:8803:e7e4:500:3548:c22e:ea52:dbc7]) by smtp.gmail.com with ESMTPSA id 46e09a7af769-7e367d4fe15sm3737018a34.18.2026.05.09.14.47.12 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 09 May 2026 14:47:14 -0700 (PDT) Message-ID: Date: Sat, 9 May 2026 16:47:12 -0500 Precedence: bulk X-Mailing-List: linux-iio@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] iio: chemical: scd30: Prevent potential divide-by-zero error To: Maxwell Doose Cc: jic23@kernel.org, Tomasz Duszynski , =?UTF-8?Q?Nuno_S=C3=A1?= , Andy Shevchenko , "open list:IIO SUBSYSTEM AND DRIVERS" , open list References: <20260509211921.84969-1-m32285159@gmail.com> Content-Language: en-US From: David Lechner In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On 5/9/26 4:36 PM, Maxwell Doose wrote: > On Sat, May 9, 2026 at 4:25 PM David Lechner wrote: >> >> On 5/9/26 4:19 PM, Maxwell Doose wrote: >>> In scd30_read_raw, the current value of tmp in the >>> IIO_CHAN_INFO_SAMP_FREQ case is unchecked. Add checking to see if the >>> value we got was 0 to prevent a divide-by-zero error. >>> >>> Fixes: 64b3d8b1b0f5 ("iio: chemical: scd30: add core driver") >>> Signed-off-by: Maxwell Doose >>> --- >>> drivers/iio/chemical/scd30_core.c | 7 +++++++ >>> 1 file changed, 7 insertions(+) >>> >>> diff --git a/drivers/iio/chemical/scd30_core.c b/drivers/iio/chemical/scd30_core.c >>> index be8c055be184..3e2bb6f4e42c 100644 >>> --- a/drivers/iio/chemical/scd30_core.c >>> +++ b/drivers/iio/chemical/scd30_core.c >>> @@ -237,6 +237,13 @@ static int scd30_read_raw(struct iio_dev *indio_dev, struct iio_chan_spec const >>> if (ret) >>> return ret; >>> >>> + /* Likely only taken if something really strange happens */ >> >> Instead of saying "strange" I would mention a possible hardware failure >> to justify the EIO return. I'm assuming this is reading the value over >> SPI or I2C? >> > > Yes, we're reading over either SPI or I2C, the sensor supports both. > Hardware failure is going to be the most likely cause of this path > being taken, but I could also see some sort of noise on the bus being > the cause. Perhaps we change it to: > > /* Likely taken if hardware is failing or noise on bus */ > > best regards, > max Sounds OK. A more verbose alternative: /* * Value of 0 is unexpected, but could happen, e.g. due to * hardware failure. */