linux-kernel - Re: [PATCH v3 4/6] typec: mux: Allow multiple mux

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Message-ID: <YiIaK8kSYGtivvhk@smile.fi.intel.com>
Date:   Fri, 4 Mar 2022 15:54:51 +0200
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     Bjorn Andersson <bjorn.andersson@...aro.org>
Cc:     Rob Herring <robh+dt@...nel.org>,
        Daniel Scally <djrscally@...il.com>,
        Heikki Krogerus <heikki.krogerus@...ux.intel.com>,
        Sakari Ailus <sakari.ailus@...ux.intel.com>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        Hans de Goede <hdegoede@...hat.com>,
        linux-usb@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-acpi@...r.kernel.org,
        Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
Subject: Re: [PATCH v3 4/6] typec: mux: Allow multiple mux_devs per mux

On Thu, Mar 03, 2022 at 02:33:49PM -0800, Bjorn Andersson wrote:
> In the Qualcomm platforms the USB/DP PHY handles muxing and orientation
> switching of the SuperSpeed lines, but the SBU lines needs to be
> connected and switched by external (to the SoC) hardware.
> 
> It's therefor necessary to be able to have the TypeC controller operate
> multiple TypeC muxes and switches. Use the newly introduced indirection
> object to handle this, to avoid having to taint the TypeC controllers
> with knowledge about the downstream hardware configuration.
> 
> The max number of devs per indirection is set to 3, which account for
> being able to mux/switch the USB HS, SS and SBU lines, as per defined
> defined in the usb-c-connector binding. This number could be grown if
> need arrises at a later point in time.

...

> +	for (i = 0; i < count; i++) {
> +		if (IS_ERR(sw_devs[i])) {
> +			err = PTR_ERR(sw_devs[i]);
> +			goto put_sw_devs;
> +		}
> +	}
>  
> -	sw->sw_dev = sw_dev;
> +	for (i = 0; i < count; i++) {
> +		WARN_ON(!try_module_get(sw_devs[i]->dev.parent->driver->owner));
> +		sw->sw_devs[i] = sw_devs[i];
> +	}
> +
> +	sw->num_sw_devs = count;
>  
>  	return sw;
> +
> +put_sw_devs:
> +	for (i = 0; i < count; i++) {

Shouldn't it be

	while (i--)

?

> +		if (!IS_ERR(sw_devs[i]))

We may get rid of this check if we guarantee that the device is NULL.

> +			put_device(&sw_devs[i]->dev);
> +	}
> +
> +	kfree(sw);
> +
> +	return ERR_PTR(err);
>  }

...

> +	for (i = 0; i < count; i++) {
> +		if (IS_ERR(mux_devs[i])) {
> +			err = PTR_ERR(mux_devs[i]);
> +			goto put_mux_devs;
> +		}

Ditto.

> +	}

...

> +put_mux_devs:
> +	for (i = 0; i < count; i++) {
> +		if (!IS_ERR(mux_devs[i]))
> +			put_device(&mux_devs[i]->dev);
> +	}

Ditto.

-- 
With Best Regards,
Andy Shevchenko