From: <Codrin.Ciubotariu@microchip.com>
To: <linux@armlinux.org.uk>, <wsa@kernel.org>
Cc: devicetree@vger.kernel.org, alexandre.belloni@bootlin.com,
kamel.bouhara@bootlin.com, linux-kernel@vger.kernel.org,
Ludovic.Desroches@microchip.com, robh+dt@kernel.org,
linux-i2c@vger.kernel.org, linux-arm-kernel@lists.infradead.org
Subject: Re: [RFC PATCH 1/4] dt-binding: i2c: add generic properties for GPIO bus recovery
Date: Mon, 27 Jul 2020 10:44:57 +0000 [thread overview]
Message-ID: <b3a04528-0053-16bf-f092-147685298ced@microchip.com> (raw)
In-Reply-To: <20200724205209.GC1551@shell.armlinux.org.uk>
On 24.07.2020 23:52, Russell King - ARM Linux admin wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
>
> On Fri, Jul 24, 2020 at 09:39:13PM +0200, Wolfram Sang wrote:
>> On Sun, Jul 05, 2020 at 11:19:18PM +0200, Wolfram Sang wrote:
>>>
>>>> +- pinctrl
>>>> + add extra pinctrl to configure SCL/SDA pins to GPIO function for bus
>>>> + recovery, call it "gpio" or "recovery" state
>>>
>>> I think we should stick with "gpio" only. That is what at91 and imx have
>>> in their bindings. pxa uses "recovery" as a pinctrl state name but I
>>> can't find any further use or documentation of that. PXA is not fully
>>> converted to the best of my knowledge, so maybe it is no problem for PXA
>>> to switch to "gpio", too? We should ask Russell King (cced).
>
> Fully converted to what? The generic handling where the i2c core layer
> handles everything to do with recovery, including the switch between
> modes?
>
> i2c-pxa _intentionally_ carefully handles the switch between i2c mode and
> GPIO mode, and I don't see a generic driver doing that to avoid causing
> any additional glitches on the bus. Given the use case that this recovery
> is targetted at, avoiding glitches is very important to keep.
Why is it not possbile to handle glitches in a generic way? I guess it
depends on the pinctl, but we could treat a worst-case scenario to
assure the switch between states is done properly.
>
>>> Russell, do you object naming the pinctrl state for bus recovery in
>>> the pxa i2c driver from "recovery" to "gpio"?
>>
>> No response, so far. I suggest now to support the "recovery" naming but
>> mark it as deprecated. Opinions?
>
> I don't have a preference on the exact naming.
>
> --
> RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
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>
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next prev parent reply other threads:[~2020-07-27 10:46 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-19 14:19 [RFC PATCH 0/4] i2c: core: add generic GPIO bus recovery Codrin Ciubotariu
2020-06-19 14:19 ` [RFC PATCH 1/4] dt-binding: i2c: add generic properties for " Codrin Ciubotariu
2020-07-05 21:19 ` Wolfram Sang
2020-07-24 19:39 ` Wolfram Sang
2020-07-24 20:52 ` Russell King - ARM Linux admin
2020-07-27 10:44 ` Codrin.Ciubotariu [this message]
2020-07-27 10:50 ` Russell King - ARM Linux admin
2020-07-30 9:00 ` Codrin.Ciubotariu
2020-08-03 14:16 ` Russell King - ARM Linux admin
2020-08-03 16:42 ` Codrin.Ciubotariu
2020-07-15 19:21 ` Rob Herring
2020-06-19 14:19 ` [RFC PATCH 2/4] i2c: core: add generic I2C GPIO recovery Codrin Ciubotariu
2020-08-02 16:54 ` Wolfram Sang
2020-08-03 13:27 ` Codrin.Ciubotariu
2020-08-03 16:49 ` wsa
2020-06-19 14:19 ` [RFC PATCH 3/4] i2c: core: treat EPROBE_DEFER when acquiring SCL/SDA GPIOs Codrin Ciubotariu
2020-08-02 17:05 ` Wolfram Sang
2020-08-03 15:33 ` Codrin.Ciubotariu
2020-08-03 16:59 ` wsa
2020-06-19 14:19 ` [RFC PATCH 4/4] i2c: at91: Move to generic GPIO bus recovery Codrin Ciubotariu
2020-08-02 17:08 ` Wolfram Sang
2020-08-03 15:42 ` Codrin.Ciubotariu
2020-08-03 16:59 ` wsa
2020-08-26 6:14 ` Wolfram Sang
2020-09-04 8:55 ` Codrin.Ciubotariu
2020-09-04 9:20 ` Wolfram Sang
2020-07-05 21:09 ` [RFC PATCH 0/4] i2c: core: add " Wolfram Sang
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