Re: [PATCH 2/2] iio: exynos-adc: add experimental touchscreen support

Arnd Bergmann
2014-07-21T10:24:32Z

On Sunday 20 July 2014 13:28:42 Dmitry Torokhov wrote:
> On Sun, Jul 20, 2014 at 02:51:37PM +0100, Jonathan Cameron wrote:
> > >>+
> > >>+ do {
> > >>+ ret =exynos_read_s3c64xx_ts(dev, NULL, &x, &y, IIO_CHAN_INFO_RAW);
> > >= exynos
> > >>+ if (ret == -ETIMEDOUT)
> > >>+ break;
> > >>+
> > >>+ pressed = x & y & ADC_DATX_PRESSED;
> > >>+ if (!pressed)
> > >>+ break;
> > >>+
> > >>+ input_report_abs(info->input, ABS_X, x & ADC_DATX_MASK);
> > >>+ input_report_abs(info->input, ABS_Y, y & ADC_DATX_MASK);
> > >>+ input_report_key(info->input, BTN_TOUCH, 1);
> > >>+ input_sync(info->input);
> > >>+
> > >>+ msleep(1);
> > >>+ } while (1);
>
> It would be nice to actually close the device even if someone is
> touching screen. Please implement open/close methods and have them set a
> flag that you would check here.

Ok. I think it's even better to move the request_irq() into the open function,
which will avoid the flag and defer the error handling into the actual opening,
as well as syncing the running irq with the close function.

> > >>+ /* data from s3c2410_ts driver */
> > >>+ info->input->name = "S3C24xx TouchScreen";
> > >>+ info->input->id.bustype = BUS_HOST;
> > >>+ info->input->id.vendor = 0xDEAD;
> > >>+ info->input->id.product = 0xBEEF;
>
> You do not need to fill these entries with fake data.

Ok, I wondered about this, but didn't want to change too much from
the old driver (I changed the version number).

> > >>+ info->input->id.version = 0x0200;

Do I need this?

> > >>@@ -576,6 +728,11 @@ static int exynos_adc_probe(struct platform_device *pdev)
> > >> err_of_populate:
> > >> device_for_each_child(&indio_dev->dev, NULL,
> > >> exynos_adc_remove_devices);
> > >>+ if (has_ts) {
> > >>+ input_unregister_device(info->input);
> > >>+ free_irq(info->tsirq, info);
>
> Are we sure that device is quiesced here and interrupt won't arrive
> between input_unregister_device() and free_irq()? I guess if you
> properly implement open/close it won't matter.

Should be fixed now.

> > >>+err_iio:
> > >> iio_device_unregister(indio_dev);
> > >> err_irq:
> > >> free_irq(info->irq, info);
> > >>@@ -595,9 +752,12 @@ static int exynos_adc_remove(struct platform_device *pdev)
> > >> struct iio_dev *indio_dev = platform_get_drvdata(pdev);
> > >> struct exynos_adc *info = iio_priv(indio_dev);
> > >>
> > >>+ input_free_device(info->input);
>
> Should be unregister, not free.

Ok.

Thanks a lot for the review! I'll send out the new version after some build testing.

Arnd