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: <ZOSj6C+4q/xUNyhA@smile.fi.intel.com>
Date:   Tue, 22 Aug 2023 15:02:48 +0300
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     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.

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");
	}
	if (!rinfo->pinctrl)
		dev_dbg(dev->dev, "pinctrl is disabled, bus recovery might not work\n");

-- 
With Best Regards,
Andy Shevchenko