From: Andy Shevchenko <andriy.shevchenko@intel.com>
To: Archit Anant <architanant5@gmail.com>
Cc: jic23@kernel.org, lars@metafoo.de, Michael.Hennerich@analog.com,
dlechner@baylibre.com, nuno.sa@analog.com, andy@kernel.org,
linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 2/4] iio: adc: ad799x: cache regulator voltages during probe
Date: Mon, 2 Mar 2026 15:13:24 +0200 [thread overview]
Message-ID: <aaWM9Csvbj6hXW8n@ashevche-desk.local> (raw)
In-Reply-To: <20260302130632.29144-3-architanant5@gmail.com>
On Mon, Mar 02, 2026 at 06:36:30PM +0530, Archit Anant wrote:
> Reading the regulator voltage via regulator_get_voltage() can be a slow
> operation. Since the reference voltages for this ADC are not expected to
> change at runtime, it is inefficient to query the regulator API every
> time userspace reads the IIO_CHAN_INFO_SCALE attribute.
>
> Cache the VCC and VREF voltages in the state structure during probe().
> This improves the performance of ad799x_read_raw() and removes the
> dependency on the regulator pointers during fast-path reads.
...
> + int vcc_uv;
> + int vref_uv;
_uV in both cases, please. It's a unit suffix.
...
> case IIO_CHAN_INFO_SCALE:
> if (st->vref)
> - ret = regulator_get_voltage(st->vref);
> + ret = st->vref_uv;
> else
> - ret = regulator_get_voltage(st->reg);
> + ret = st->vcc_uv;
> if (ret < 0)
> return ret;
Isn't it a dead check now?
--
With Best Regards,
Andy Shevchenko
next prev parent reply other threads:[~2026-03-02 13:13 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-02 13:06 [PATCH v3 0/4] iio: adc: ad799x: modernize resource management Archit Anant
2026-03-02 13:06 ` [PATCH v3 1/4] iio: adc: ad799x: make rx_buf static and DMA-safe Archit Anant
2026-03-02 16:29 ` David Lechner
2026-03-02 16:31 ` David Lechner
2026-03-02 13:06 ` [PATCH v3 2/4] iio: adc: ad799x: cache regulator voltages during probe Archit Anant
2026-03-02 13:13 ` Andy Shevchenko [this message]
2026-03-02 16:37 ` David Lechner
2026-03-02 13:06 ` [PATCH v3 3/4] iio: adc: ad799x: use devm_add_action_or_reset for regulators Archit Anant
2026-03-02 13:16 ` Andy Shevchenko
2026-03-02 16:35 ` David Lechner
2026-03-02 13:06 ` [PATCH v3 4/4] iio: adc: ad799x: use devm_iio_device_register and drop remove Archit Anant
2026-03-02 13:17 ` Andy Shevchenko
2026-03-02 16:28 ` [PATCH v3 0/4] iio: adc: ad799x: modernize resource management David Lechner
2026-03-03 5:11 ` Archit Anant
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