From: Kieran Bingham <kieran.bingham@ideasonboard.com>
To: Sakari Ailus <sakari.ailus@linux.intel.com>,
Umang Jain <umang.jain@ideasonboard.com>
Cc: linux-media@vger.kernel.org,
open list <linux-kernel@vger.kernel.org>,
Tommaso Merciai <tomm.merciai@gmail.com>
Subject: Re: [PATCH] media: imx335: Fix reset-gpio handling
Date: Mon, 29 Jul 2024 11:22:06 +0100 [thread overview]
Message-ID: <172224852603.392292.14437094530843053506@ping.linuxembedded.co.uk> (raw)
In-Reply-To: <ZqdYqaMDWjHrNXPh@kekkonen.localdomain>
Quoting Sakari Ailus (2024-07-29 09:54:01)
> Hi Umang,
>
> On Mon, Jul 29, 2024 at 02:19:32PM +0530, Umang Jain wrote:
> > Hi Sakari
> >
> > On 29/07/24 1:11 pm, Sakari Ailus wrote:
> > > Hi Umang,
> > >
> > > Thanks for the patch.
> > >
> > > On Mon, Jul 29, 2024 at 11:35:35AM +0530, Umang Jain wrote:
> > > > The imx335 reset-gpio is initialised with GPIO_OUT_LOW during probe.
> > > Should it be initialised to high instead, to enable reset?
> >
> > This initialization matches the physical line status, which is low in this
> > case.
>
> Documentation/driver-api/gpio/consumer.rst:
>
> * GPIOD_OUT_LOW to initialize the GPIO as output with a value of 0.
>
> ...
>
> Note that the initial value is *logical* and the physical line
> level depends on whether the line is configured active high or
> active low (see :ref:`active_low_semantics`).
>
Yes, I think this patch should also update/fix the call in
imx335_parse_hw_config()
/* Request optional reset pin */
imx335->reset_gpio = devm_gpiod_get_optional(imx335->dev, "reset",
- GPIOD_OUT_LOW);
+ GPIOD_OUT_HIGH);
To make sure it starts off in reset until it's set accordingly in
imx335_power_{on,off}()
--
Kieran
> --
> Sakari Ailus
next prev parent reply other threads:[~2024-07-29 10:22 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-07-29 6:05 Umang Jain
2024-07-29 7:41 ` Sakari Ailus
2024-07-29 8:49 ` Umang Jain
2024-07-29 8:54 ` Sakari Ailus
2024-07-29 10:22 ` Kieran Bingham [this message]
2024-07-29 8:12 ` Jacopo Mondi
2024-07-29 8:48 ` Umang Jain
2024-07-29 9:19 ` Jacopo Mondi
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