On Wed, Nov 16, 2011 at 07:28:35PM +0100, Heiko Stübner wrote:
> Am Mittwoch 16 November 2011, 17:48:07 schrieb Dmitry Torokhov:
> > On Wed, Nov 16, 2011 at 12:02:07PM +0100, Heiko Stübner wrote:
> > > Hi Dmitry,
> > >
> > > Am Mittwoch 16 November 2011, 08:18:22 schrieb Dmitry Torokhov:
> > > > Hi Heiko,
> > > >
> > > > On Fri, Oct 21, 2011 at 10:43:47AM +0200, Heiko Stübner wrote:
> > > > > There exist tilt switches that simply report their tilt-state via
> > > > > some gpios.
> > > > >
> > > > > The number and orientation of their axes can vary depending on the
> > > > > switch used and the build of the device. Also two or more one-axis
> > > > > switches could be combined to provide multi-dimensional orientation.
> > > > >
> > > > > One example of a device using such a switch is the family of Qisda
> > > > > ebook readers, where the switch provides information about the
> > > > > landscape / portrait orientation of the device. The example in
> > > > > Documentation/input/gpio-tilt.txt documents exactly this one-axis
> > > > > device.
> > > >
> > > > Looks very nice, just a few comments below.
> > >
> > > thanks for your review, comments below
> > >
> > > [...]
> > >
> > > > > +static void gpio_tilt_polled_poll(struct input_polled_dev *dev)
> > > > > +{
> > > > > + struct gpio_tilt_polled_dev *bdev = dev->private;
> > > >
> > > > Call it tdev or tilt or tilt_dev or something? bdev is not very fitting
> > > > here.
> > >
> > > ok, will change this
> > >
> > > [...]
> > >
> > > > > +static int __devinit gpio_tilt_polled_probe(struct platform_device
> > > > > *pdev) +{
> > > > > + struct gpio_tilt_platform_data *pdata = pdev->dev.platform_data;
> > > > > + struct device *dev = &pdev->dev;
> > > > > + struct gpio_tilt_polled_dev *bdev;
> > > > > + struct input_polled_dev *poll_dev;
> > > > > + struct input_dev *input;
> > > > > + int error, i;
> > > > > +
> > > > > + if (!pdata || !pdata->poll_interval)
> > > > > + return -EINVAL;
> > > > > +
> > > > > + bdev = kzalloc(sizeof(struct gpio_tilt_polled_dev), GFP_KERNEL);
> > > > > + if (!bdev) {
> > > > > + dev_err(dev, "no memory for private data\n");
> > > > > + return -ENOMEM;
> > > > > + }
> > > > > +
> > > > > + bdev->gpios = kmemdup(pdata->gpios,
> > > > > + pdata->nr_gpios * sizeof(struct gpio),
> > > > > + GFP_KERNEL);
> > > > > + if (bdev->gpios == NULL) {
> > > > > + dev_err(&pdev->dev, "Failed to allocate gpio data\n");
> > > > > + error = -ENOMEM;
> > > > > + goto err_free_bdev;
> > > > > + }
> > > > > + bdev->nr_gpios = pdata->nr_gpios;
> > > >
> > > > Do you actually need to do this? Can't you just store the pointer to
> > > > the platform data and use it instead? Same goes for the rest of items
> > > > you are cloning.
> > >
> > > As I understand it from previous patches, platform data should be
> > > markable as initdata which means the kernel discards it after boot.
> > > Therefore it cannot be
> >
> > Absolutely not. Consider what happens if your driver is a module and is
> > loaded after boot is complete. Or you unload and reload it;
> > platform_data has to stay there, it later must not be marked initdata
> > and freed.
>
> I don't claim to grasp every bit the initdata routines do :-) . But I was
> under the impression that allowing people to make it initdata if necessary and
> not building stuff as modules was the correct way.
Huh? Forcing non-modular build is "the correct way"?
>
> Last time I submitted a regulator patch Mark Brown wrote:
>
> Monday 29 August 2011, 11:18:07 Mark Brown wrote
> [...]
> > This also fixes the use of platform data after probe - platform data
> > should be able to be marked as initdata which may mean that the kernel
> > discards it after boot.
>
> The bq24022 driver in question can be build as a module.
>
Quoting Russell King "That's totally buggered, and that's putting it
kindly.":
http://www.spinics.net/lists/linux-input/msg16335.html
Thanks.
--
Dmitry
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