From: David Lechner <dlechner@baylibre.com>
To: "Salah Triki" <salah.triki@gmail.com>,
"Puranjay Mohan" <puranjay@kernel.org>,
"Jonathan Cameron" <jic23@kernel.org>,
"Nuno Sá" <nuno.sa@analog.com>,
"Andy Shevchenko" <andy@kernel.org>
Cc: linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] iio: temperature: tmp117: fix calibbias cache update on I2C write failure
Date: Sat, 22 Aug 2026 13:29:02 -0500 [thread overview]
Message-ID: <1711ef3d-727a-4898-9aa1-887369ddbc06@baylibre.com> (raw)
In-Reply-To: <20260822004929.13643-1-salah.triki@gmail.com>
On 8/21/26 7:49 PM, Salah Triki wrote:
> The calibbias cache (data->calibbias) was updated before the I2C
> write to TMP117_REG_TEMP_OFFSET was known to succeed. If the write
> failed, the function correctly returned an error, but the driver's
> internal cache had already been updated to the new value.
>
> This causes the cache and the actual hardware register to go out of
> sync: a subsequent write of the same value would be silently
> skipped by the early "if (off == data->calibbias) return 0;" check,
> since the cache matches even though the register was never
> successfully updated.
>
> Update data->calibbias only after confirming the I2C write
> succeeded, so the cache always reflects the actual state of the
> device.
>
For fixes, it is always useful to know how you found the problem. I'm
guessing code inspection here.
> Fixes: df041e737a38 ("iio: temperature: add driver support for ti tmp117")
> Signed-off-by: Salah Triki <salah.triki@gmail.com>
> ---
prev parent reply other threads:[~2026-08-22 18:29 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-22 0:49 [PATCH] iio: temperature: tmp117: fix calibbias cache update on I2C write failure Salah Triki
2026-08-22 8:16 ` Joshua Crofts
2026-08-22 18:29 ` David Lechner [this message]
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