linux-kernel - Re: [PATCH v3] Currently if the SoC needs pinctrl to switch the SCL and SDA from the I2C function to GPIO function, the recovery won't work.

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Message-ID: <22aa8679-7f08-fc82-3262-db1cfc953b36@kalrayinc.com>
Date:   Tue, 22 Aug 2023 14:18:44 +0200
From:   Yann Sionneau <ysionneau@...rayinc.com>
To:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Yann Sionneau <ysionneau@...ray.eu>
Cc:     Jarkko Nikula <jarkko.nikula@...ux.intel.com>,
        Mika Westerberg <mika.westerberg@...ux.intel.com>,
        Julian Vetter <jvetter@...rayinc.com>,
        linux-i2c@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3] Currently if the SoC needs pinctrl to switch the SCL
 and SDA from the I2C function to GPIO function, the recovery won't work.

Hi,

On 8/22/23 14:02, Andy Shevchenko wrote:
> On Tue, Aug 22, 2023 at 11:15:55AM +0200, Yann Sionneau wrote:
>> scl-gpio = <>;
>> sda-gpio = <>;
>>
>> Are not enough for some SoCs to have a working recovery.
>> Some need:
>>
>> scl-gpio = <>;
>> sda-gpio = <>;
>> pinctrl-names = "default", "recovery";
>> pinctrl-0 = <&i2c_pins_hw>;
>> pinctrl-1 = <&i2c_pins_gpio>;
>>
>> The driver was not filling rinfo->pinctrl with the device node
>> pinctrl data which is needed by generic recovery code.
> ...
>
>> +	rinfo->pinctrl = devm_pinctrl_get(dev->dev);
>> +	if (IS_ERR(rinfo->pinctrl)) {
>> +		if (PTR_ERR(rinfo->pinctrl) == -EPROBE_DEFER)
>> +			return PTR_ERR(rinfo->pinctrl);
>> +
>> +		rinfo->pinctrl = NULL;
>> +		dev_err(dev->dev, "getting pinctrl info failed: bus recovery might not work\n");
>> +	} else if (!rinfo->pinctrl) {
>> +		dev_dbg(dev->dev, "pinctrl is disabled, bus recovery might not work\n");
>> +	}
> A bit of bikeshedding, would the below be slightly better?
>
> 	rinfo->pinctrl = devm_pinctrl_get(dev->dev);
> 	if (IS_ERR(rinfo->pinctrl)) {
> 		if (PTR_ERR(rinfo->pinctrl) == -EPROBE_DEFER)
> 			return PTR_ERR(rinfo->pinctrl);
>
> 		rinfo->pinctrl = NULL;
> 		dev_err(dev->dev, "getting pinctrl info failed, disabling...\n");

I think the dev_err() message change is not very clear because one might 
think that "disabling" means that the i2c adapter is getting disabled.

Maybe we can put "getting pinctrl info failed, disabling recovery..."?

> 	}
> 	if (!rinfo->pinctrl)
> 		dev_dbg(dev->dev, "pinctrl is disabled, bus recovery might not work\n");
>
Ah yes, I like the getting rid of the `else` part. LGTM I'll re-send 
with that.

Regards,

-- 

Yann