From: Detlev Casanova <detlev.casanova@collabora.com>
To: Mark Brown <broonie@kernel.org>
Cc: linux-kernel@vger.kernel.org,
Dave Stevenson <dave.stevenson@raspberrypi.com>,
Liam Girdwood <lgirdwood@gmail.com>
Subject: Re: [PATCH v2 8/9] regulator/rpi-panel-attiny: Don't read the LCD power status
Date: Mon, 24 Jan 2022 15:22:35 -0500 [thread overview]
Message-ID: <5533342.DvuYhMxLoT@falcon9> (raw)
In-Reply-To: <Yerfr8Nj43TTPcAF@sirena.org.uk>
On Friday, January 21, 2022 11:30:39 A.M. EST Mark Brown wrote:
> On Fri, Jan 21, 2022 at 10:20:55AM -0500, Detlev Casanova wrote:
> > From: Dave Stevenson <dave.stevenson@raspberrypi.com>
> >
> > The I2C to the Atmel is very fussy, and locks up easily on
> > Pi0-3 particularly on reads.
> >
> > The LCD power status is controlled solely by this driver, so
> > rather than reading it back from the Atmel, use the cached
> > status last set.
>
> If that's the case since you're using regmap would it not make sense to
> enable caching in order to minimise reads in general.
Would caching avoid all reads if the values are written at least once before?
The idea here is to make sure they are never read, I'm not sure if the regmap
cache ensures no read in this situation.
next prev parent reply other threads:[~2022-01-24 20:48 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-21 15:20 [PATCH v2 0/9] regulator: rpi-panel: Support official Raspberry Pi 7 inches touchscreen Detlev Casanova
2022-01-21 15:20 ` [PATCH v2 1/9] regulator: rpi-panel: Register with a unique backlight name Detlev Casanova
2022-01-21 16:26 ` Mark Brown
2022-01-21 18:11 ` Detlev Casanova
2022-01-21 15:20 ` [PATCH v2 2/9] regulator: rpi-panel: Handle I2C errors/timing to the Atmel Detlev Casanova
2022-01-21 15:20 ` [PATCH v2 3/9] regulator: rpi-panel: Serialise operations Detlev Casanova
2022-01-21 15:20 ` [PATCH v2 4/9] regulator: rpi-panel: Ensure the backlight is off during probe Detlev Casanova
2022-01-21 15:20 ` [PATCH v2 5/9] regulator: rpi-panel: Convert to drive lines directly Detlev Casanova
2022-01-21 15:20 ` [PATCH v2 6/9] regulator: rpi-panel: Add GPIO control for panel and touch resets Detlev Casanova
2022-01-21 15:20 ` [PATCH v2 7/9] regulator: rpi-panel: Remove get_brightness hook Detlev Casanova
2022-01-21 15:20 ` [PATCH v2 8/9] regulator/rpi-panel-attiny: Don't read the LCD power status Detlev Casanova
2022-01-21 16:30 ` Mark Brown
2022-01-24 20:22 ` Detlev Casanova [this message]
2022-01-24 20:45 ` Mark Brown
2022-01-21 15:20 ` [PATCH v2 9/9] regulator/rpi-panel-attiny: Use two transactions for I2C read Detlev Casanova
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