linux-kernel - Re: [PATCH v2] i2c: designware: platdrv: Set class based on dmi

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Date:   Wed, 24 Jun 2020 16:22:31 +0300
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     Ricardo Ribalda <ribalda@...nel.org>
Cc:     Jarkko Nikula <jarkko.nikula@...ux.intel.com>,
        Mika Westerberg <mika.westerberg@...ux.intel.com>,
        linux-i2c@...r.kernel.org, linux-kernel@...r.kernel.org,
        Wolfram Sang <wsa@...nel.org>
Subject: Re: [PATCH v2] i2c: designware: platdrv: Set class based on dmi

On Wed, Jun 24, 2020 at 01:25:30PM +0200, Ricardo Ribalda wrote:
> Current AMD's zen-based APUs use this core for some of its i2c-buses.
> 
> With this patch we re-enable autodetection of hwmon-alike devices, so
> lm-sensors will be able to work automatically.
> 
> It does not affect the boot-time of embedded devices, as the class is
> set based on the dmi information.

I think it misses Fixes tag. And...

...

> +static bool dw_i2c_hwmon_bus(void)
> +{

> +	const char *product_name = dmi_get_system_info(DMI_PRODUCT_NAME);

Split this, so the assignment will be attached to the check below.

> +	if (!product_name)
> +		return false;
> +

> +	if (strstr(product_name, "QT5222"))
> +		return true;

I don't like this part at all. Why do you need strstr()? Can you provide in the
commit message relevant fields from dmidecode (or sysfs)?

> +	return false;
> +}

In general it's not how we do DMI based quirks, rather using table and call
match function. In that case you can take class as a driver_data. Much more
flexible in case we need to extend.

...

> -	adap->class = I2C_CLASS_DEPRECATED;
> +	adap->class = dw_i2c_hwmon_bus() ? I2C_CLASS_HWMON : I2C_CLASS_DEPRECATED;

...since the patch has it unconditionally, I would go unconditionally. But if
Wolfram insists, then see above.

-- 
With Best Regards,
Andy Shevchenko