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From: Kamel Bouhara <kamel.bouhara@bootlin.com>
To: linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 2/4] i2c: at91: implement i2c bus recovery
Date: Thu, 24 Oct 2019 14:29:13 +0200	[thread overview]
Message-ID: <ead1bd39-5834-b970-06b7-fdc9c50bb780@bootlin.com> (raw)
In-Reply-To: <20191010065408.y7i7aywdztgixv47@M43218.corp.atmel.com>


On 10/10/2019 08:54, Ludovic Desroches wrote:
> On Wed, Oct 09, 2019 at 04:01:47PM +0200, Alexandre Belloni wrote:
>>
>> On 09/10/2019 15:55:00+0200, Ludovic Desroches wrote:
>>> On Wed, Oct 02, 2019 at 04:46:56PM +0200, Kamel Bouhara wrote:
>>>> External E-Mail
>>>>
>>>>
>>>> Implement i2c bus recovery when slaves devices might hold SDA low.
>>>> In this case re-assign SCL/SDA to gpios and issue 9 dummy clock pulses
>>>> until the slave release SDA.
>>>>
>>>
>>> Hi Kamel,
>>>
Hi Ludovic,

>>> Thanks for adding this new feature. As I see patches only for sama5d3 and
>>> sama5d4, I assume it has not been tested with a sama5d2, isn't it?
>>>
>>
>> I there a point having it on sama5d2 as the controller already supports
>> this feature?
>>
> 
> Right, I was focused on pinctrl and forget we have this feature
> supported by the IP.
> 
>>> I doubt it works with a sama5d2 because of the pinctrl. I also wonder if it can
>>> work if we add .strict = true to pinmux_ops which is something plan for the
>>> future...
>>>
>>
>> I don't see why it wouldn't work with strict as this is switching muxing
>> properly instead of using the pins for two functions at the same time.
>>
> 
> Not sure devm_gpiod_get won't fail with strict.
> 
Actually the strict flag is checked in the pinmux core to allow the pin 
request.

What is the purpose to enable it ? It seems to break a lot things, eg. 
on sama5d3 :

# dmesg |grep pin
pinctrl-at91 ahb:apb:pinctrl@fffff200: pin pioA18 already requested by 
f801c000.i2c; cannot claim for fffff200.gpio:18
pinctrl-at91 ahb:apb:pinctrl@fffff200: pin-18 (fffff200.gpio:18) status -22
pinctrl-at91 ahb:apb:pinctrl@fffff200: pin pioA19 already requested by 
f801c000.i2c; cannot claim for fffff200.gpio:19
pinctrl-at91 ahb:apb:pinctrl@fffff200: pin-19 (fffff200.gpio:19) status -22
pinctrl-at91 ahb:apb:pinctrl@fffff200: pin pioE9 already requested by 
500000.gadget; cannot claim for fffffa00.gpio:137
pinctrl-at91 ahb:apb:pinctrl@fffff200: pin-137 (fffffa00.gpio:137) 
status -22
pinctrl-at91 ahb:apb:pinctrl@fffff200: pin pioE0 already requested by 
f0000000.mmc; cannot claim for fffffa00.gpio:128
pinctrl-at91 ahb:apb:pinctrl@fffff200: pin-128 (fffffa00.gpio:128) 
status -22
pinctrl-at91 ahb:apb:pinctrl@fffff200: pin pioE1 already requested by 
f8000000.mmc; cannot claim for fffffa00.gpio:129
pinctrl-at91 ahb:apb:pinctrl@fffff200: pin-129 (fffffa00.gpio:129) 
status -22
pinctrl-at91 ahb:apb:pinctrl@fffff200: pin pioE29 already requested by 
gpio_keys; cannot claim for fffffa00.gpio:157
pinctrl-at91 ahb:apb:pinctrl@fffff200: pin-157 (fffffa00.gpio:157) 
status -22

> Ludovic
> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
> 

-- 
Kamel Bouhara, Bootlin
Embedded Linux and kernel engineering
https://bootlin.com

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  reply	other threads:[~2019-10-24 12:29 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-02 14:46 [PATCH 0/4] i2c bus recovery for Microchip SoCs Kamel Bouhara
2019-10-02 14:46 ` [PATCH 1/4] dt-bindings: i2c: at91: document optional bus recovery properties Kamel Bouhara
2019-10-02 14:46 ` [PATCH 2/4] i2c: at91: implement i2c bus recovery Kamel Bouhara
2019-10-04  9:35   ` Claudiu.Beznea
2019-10-04 20:39     ` Uwe Kleine-König
2019-10-07 10:17       ` Claudiu.Beznea
2019-10-09 13:55   ` Ludovic Desroches
2019-10-09 14:01     ` Alexandre Belloni
2019-10-10  6:54       ` Ludovic Desroches
2019-10-24 12:29         ` Kamel Bouhara [this message]
2019-10-25  7:04           ` Ludovic.Desroches
2019-10-21 20:20   ` Wolfram Sang
2019-10-22  7:59     ` Kamel Bouhara
2019-10-24 14:08       ` Codrin.Ciubotariu
2019-10-24 15:07         ` Wolfram Sang
2019-10-25  1:14           ` Phil Reid
2020-08-25 13:28             ` Wolfram Sang
2020-08-25 23:44               ` Phil Reid
2019-10-02 14:46 ` [PATCH 3/4] ARM: at91/dt: sama5d3: add i2c gpio pinctrl Kamel Bouhara
2019-10-02 14:46 ` [PATCH 4/4] ARM: at91/dt: sama5d4: " Kamel Bouhara
2019-10-15 19:10 ` [PATCH 0/4] i2c bus recovery for Microchip SoCs Rob Herring

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