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

Dmitry Torokhov
2014-07-21T14:44:49Z

On Mon, Jul 21, 2014 at 12:23:58PM +0200, Arnd Bergmann wrote:
> 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.

I do not quite like acquiring resources needed in open. I think drivers should
do all resource acquisition in probe() and leave open()/close() to
activate/quiesce devices.

>
> > > >>+ /* 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?

Not really.

Thanks.

--
Dmitry