[PATCH v3 1/3] usb: fsl-mxc-udc: replace cpu_is_xxx() with platform_device_id

[Felipe Balbi]

Hi,

On Mon, Jan 14, 2013 at 11:50:41AM +0100, Marc Kleine-Budde wrote:
> On 01/14/2013 11:39 AM, Felipe Balbi wrote:
> > On Mon, Jan 14, 2013 at 11:34:05AM +0100, Marc Kleine-Budde wrote:
> >> On 01/14/2013 11:24 AM, Felipe Balbi wrote:
> >>> On Mon, Jan 14, 2013 at 11:18:53AM +0100, Marc Kleine-Budde wrote:
> >>>> On 01/14/2013 11:16 AM, Felipe Balbi wrote:
> >>>>> Hi,
> >>>>>
> >>>>> On Mon, Jan 14, 2013 at 06:12:39PM +0800, Peter Chen wrote:
> >>>>>> @@ -2756,22 +2753,41 @@ static int fsl_udc_otg_resume(struct device *dev)
> >>>>>>  
> >>>>>>  	return fsl_udc_resume(NULL);
> >>>>>>  }
> >>>>>> -
> >>>>>>  /*-------------------------------------------------------------------------
> >>>>>>  	Register entry point for the peripheral controller driver
> >>>>>>  --------------------------------------------------------------------------*/
> >>>>>> -
> >>>>>> +static const struct platform_device_id fsl_udc_devtype[] = {
> >>>>>> +	{
> >>>>>> +		.name = "imx-udc-mx25",
> >>>>>> +		.driver_data = IMX25_UDC,
> >>>>>> +	}, {
> >>>>>> +		.name = "imx-udc-mx27",
> >>>>>> +		.driver_data = IMX27_UDC,
> >>>>>> +	}, {
> >>>>>> +		.name = "imx-udc-mx31",
> >>>>>> +		.driver_data = IMX31_UDC,
> >>>>>> +	}, {
> >>>>>> +		.name = "imx-udc-mx35",
> >>>>>> +		.driver_data = IMX35_UDC,
> >>>>>> +	}, {
> >>>>>> +		.name = "imx-udc-mx51",
> >>>>>> +		.driver_data = IMX51_UDC,
> >>>>>> +	}
> >>>>>> +};
> >>>>>
> >>>>> I wonder if your driver-data is actually needed since you can use string
> >>>>> comparisson to achieve the exact same outcome.
> >>>>
> >>>> Why use a string compare, if the kernel infrastructure already does this
> >>>> for you?
> >>>
> >>> what do you mean ? What kernel infrastructure is doing waht for me ?
> >>
> >> The kernel infrastructure is doing the string compare for you to match
> >> the device against the driver (via platform_device_id->name). You get
> >> the a pointer to the driver_data for free. So you don't need any string
> >> compare in the driver later.
> > 
> > but current driver data is just duplicating name with an integer, it's
> > pretty useless driver data.
> 
> I don't think so - another argument:
> Less code. As struct platform_device_id is a static array the space is
> allocated anyway. So it doesn't make any difference if driver_data is
> NULL or not. Later you just need to make an integer comparison instead
> of a call to a strcmp(), if you have a switch/case and IMX*_UDC is an
> enum, the compiler will warn you if you've missed an IMX variant.

fair enough, but then don't create a different enum value for each imx
instance if they're mostly the same. Differentiate only what's actually
different.

-- 
balbi
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