On Wed, Feb 02, 2011 at 10:39:59PM -0800, Andres Salomon wrote:
> On Wed, 2 Feb 2011 22:05:21 -0800
> Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx> wrote:
>
> > On Wed, Feb 02, 2011 at 08:15:22PM -0800, Andres Salomon wrote:
> > > static int __devinit twl4030_vibra_probe(struct platform_device
> > > *pdev) {
> > > - struct twl4030_codec_vibra_data *pdata =
> > > pdev->dev.platform_data;
> > > + struct twl4030_codec_vibra_data *pdata =
> > > platform_get_drvdata(pdev);
> >
> > No, device's drvdata belongs to _this_ driver, and it is supposed to
> > manage it and use as it sees fit.
>
> Right, so it's used to pass data to the probe function; once the probe
> function has obtained the pdata pointer, it's free to do with it what
> it will.
>
>
> >
> > Note platform_set_drvdata(pdev, info) later in this function along
> > with platform_set_drvdata(pdev, NULL) in twl4030_vibra_remove(),
> > which means that with your change you will be able to bind the device
> > only once.
> >
>
> Hm, good point; if the driver is reloaded, the pdev that was created by
> mfd-core will have lost the pointer to pdata.
>
> I wonder if I should be using mfd's driver_data instead. I used
> platform_data because a bunch of drivers had already made use of it to
> pass cell information..
Then they are doing it incorrectly. One possible way is to have parent
device carry relevant data in its drvdata and have children get it from
there.
--
Dmitry
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