From: Jonathan Cameron <jic23@kernel.org>
To: Andy Shevchenko <andriy.shevchenko@intel.com>
Cc: "Baek Kyu, Kim" <pocj8ur4in@gmail.com>,
linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org,
"David Lechner" <dlechner@baylibre.com>,
"Nuno Sá" <nuno.sa@analog.com>,
"Andy Shevchenko" <andy@kernel.org>
Subject: Re: [PATCH] iio: dac: mcp4725: Update the cached DAC value only on success
Date: Sun, 25 Oct 2026 22:31:41 +0000 [thread overview]
Message-ID: <20261025223141.0cd4ac03@jic23-hlaptop> (raw)
In-Reply-To: <at5v4pw34L8Cj0vU@ashevche-desk.local>
On Sun, 25 Oct 2026 23:08:50 +0200
Andy Shevchenko <andriy.shevchenko@intel.com> wrote:
> On Sun, Oct 25, 2026 at 11:13:51PM +0900, Baek Kyu, Kim wrote:
> > mcp4725_write_raw() updates dac_value even if mcp4725_set_value() rejects
> > the requested value or reports an I2C transfer error. After writing 1000,
> > a rejected write of 4096 returns -EINVAL without an I2C transfer, but
> > out_voltage0_raw reports 4096. A later powerdown exit sends 00 00 instead
> > of the 03 e8 frame for the last successful value. The EEPROM store path
> > uses the same cache.
> >
> > Return the setter error before updating dac_value. This keeps the last
> > successful software value for readback, powerdown exit and EEPROM writes.
>
> Does it need a Fixes tag?
Yes. Given I wanted to reduce outstanding patches, I added it an applied
to the fixes-togreg branch of iio.git
This goes all the way back to 2012 introduction of the driver.
Fixes: cf35ad61aca2 ("iio: add mcp4725 I2C DAC driver")
>
> > Signed-off-by: Baek Kyu, Kim <pocj8ur4in@gmail.com>
>
prev parent reply other threads:[~2026-10-25 22:31 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-25 14:13 Baek Kyu, Kim
2026-10-25 21:08 ` Andy Shevchenko
2026-10-25 22:31 ` Jonathan Cameron [this message]
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