From: Andy Shevchenko <andriy.shevchenko@intel.com>
To: "Sabau, Radu bogdan" <Radu.Sabau@analog.com>
Cc: "David Lechner" <dlechner@baylibre.com>,
"Lars-Peter Clausen" <lars@metafoo.de>,
"Hennerich, Michael" <Michael.Hennerich@analog.com>,
"Jonathan Cameron" <jic23@kernel.org>,
"Sa, Nuno" <Nuno.Sa@analog.com>,
"Andy Shevchenko" <andy@kernel.org>,
"Rob Herring" <robh@kernel.org>,
"Krzysztof Kozlowski" <krzk+dt@kernel.org>,
"Conor Dooley" <conor+dt@kernel.org>,
"Uwe Kleine-König" <ukleinek@kernel.org>,
"Liam Girdwood" <lgirdwood@gmail.com>,
"Mark Brown" <broonie@kernel.org>,
"Linus Walleij" <linusw@kernel.org>,
"Bartosz Golaszewski" <brgl@kernel.org>,
"Philipp Zabel" <p.zabel@pengutronix.de>,
"linux-iio@vger.kernel.org" <linux-iio@vger.kernel.org>,
"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-pwm@vger.kernel.org" <linux-pwm@vger.kernel.org>,
"linux-gpio@vger.kernel.org" <linux-gpio@vger.kernel.org>
Subject: Re: [PATCH v3 2/4] iio: adc: ad4691: add initial driver for AD4691 family
Date: Mon, 16 Mar 2026 18:13:57 +0200 [thread overview]
Message-ID: <abgsRcTfhELaxjLz@ashevche-desk.local> (raw)
In-Reply-To: <LV9PR03MB84141484B1472E01578A2243F740A@LV9PR03MB8414.namprd03.prod.outlook.com>
On Mon, Mar 16, 2026 at 03:57:53PM +0000, Sabau, Radu bogdan wrote:
> > From: David Lechner <dlechner@baylibre.com>
> > Sent: Monday, March 16, 2026 5:51 PM
> > On 3/16/26 10:29 AM, Sabau, Radu bogdan wrote:
> > >> From: Andy Shevchenko <andriy.shevchenko@intel.com>
> > >> Sent: Friday, March 13, 2026 12:58 PM
> > >> To: Sabau, Radu bogdan <Radu.Sabau@analog.com>
...
> > >>> + u32 acc_mask[2] = { mask & 0xFF, mask >> 8 };
> > >>
> > >> This looks quite wrong. Is it for sure like two 32-bit stances per each mask
> > >> byte? If not, this should be __le16 acc_mask = cpu_to_le16(~BIT(...));
> > >>
> > >
> > > Hi Andy,
> > >
> > > Each acc_mask has its own register, therefore the u32 acc_mask[2] is
> > > intentional - since the regmap is configured with val_bits=32 - the 4-byte
> > > stride matches what regmap reads. However, I understand how this
> > > can be confusing for anyone reading the code, therefore I propose
> > > two ways for this :
> > >
> > > 1. Keep regmap_bulk_write and add a comment above acc_mask explaining
> > > why u32 is used, although these register values are 8 bits.
> > > 2. Switch to regmap_multi_reg_write, which takes explicit (reg, value) pairs
> > > and sidesteps the ambiguity entirely.
> > >
> > > Do you have a preference?
> >
> > Since we already have a custom read/write functions to handle different
> > register sizes and the chip can read more than one consecutive register
> > at once, can we just call this a single register and add a special case
> > to ad4691_reg_read/write() to handle it? Then we can just do a regular
> > regmap_read/write() functions to access it as a single 16-bit value.
>
> This sounds even better! I will have this in the next version!
I also second David's suggestion, please go for it.
--
With Best Regards,
Andy Shevchenko
next prev parent reply other threads:[~2026-03-16 16:14 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-13 10:07 [PATCH v3 0/4] iio: adc: ad4691: add driver for AD4691 multichannel SAR ADC family Radu Sabau via B4 Relay
2026-03-13 10:07 ` [PATCH v3 1/4] dt-bindings: iio: adc: add bindings for AD4691 family Radu Sabau via B4 Relay
2026-03-14 9:41 ` Krzysztof Kozlowski
2026-03-16 11:55 ` Sabau, Radu bogdan
2026-03-14 15:29 ` David Lechner
2026-03-14 16:19 ` David Lechner
2026-03-16 12:39 ` Sabau, Radu bogdan
2026-03-16 12:55 ` Sabau, Radu bogdan
2026-03-16 15:14 ` David Lechner
2026-03-16 15:47 ` Sabau, Radu bogdan
2026-03-14 18:18 ` David Lechner
2026-03-13 10:07 ` [PATCH v3 2/4] iio: adc: ad4691: add initial driver " Radu Sabau via B4 Relay
2026-03-13 10:58 ` Andy Shevchenko
2026-03-16 15:29 ` Sabau, Radu bogdan
2026-03-16 15:51 ` David Lechner
2026-03-16 15:57 ` Sabau, Radu bogdan
2026-03-16 16:13 ` Andy Shevchenko [this message]
2026-03-14 11:04 ` Nuno Sá
2026-03-16 14:29 ` Sabau, Radu bogdan
2026-03-16 16:00 ` Sabau, Radu bogdan
2026-03-14 16:36 ` David Lechner
2026-03-16 13:01 ` Sabau, Radu bogdan
2026-03-25 15:01 ` kernel test robot
2026-03-13 10:07 ` [PATCH v3 3/4] iio: adc: ad4691: add triggered buffer support Radu Sabau via B4 Relay
2026-03-13 11:13 ` Andy Shevchenko
2026-03-13 12:09 ` Sabau, Radu bogdan
2026-03-13 14:40 ` Andy Shevchenko
2026-03-14 18:37 ` David Lechner
2026-03-16 13:22 ` Sabau, Radu bogdan
2026-03-16 15:37 ` David Lechner
2026-03-16 15:56 ` Sabau, Radu bogdan
2026-03-16 16:44 ` David Lechner
2026-03-17 9:27 ` Sabau, Radu bogdan
2026-03-13 10:07 ` [PATCH v3 4/4] iio: adc: ad4691: add SPI offload support Radu Sabau via B4 Relay
2026-03-14 19:37 ` David Lechner
2026-03-16 13:31 ` Sabau, Radu bogdan
2026-03-13 11:14 ` [PATCH v3 0/4] iio: adc: ad4691: add driver for AD4691 multichannel SAR ADC family Andy Shevchenko
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