RE: [PATCH 1/2] Input: edt-ft5x06 - use get_unaligned_be16()

David Laight
2019-06-25T13:00:24Z

From: Andy Shevchenko
> Sent: 25 June 2019 11:50
> To: David Laight
> Cc: Dmitry Torokhov; linux-input@vger.kernel.org; Marco Felsch; Benoit Parrot; linux-
> kernel@vger.kernel.org
> Subject: Re: [PATCH 1/2] Input: edt-ft5x06 - use get_unaligned_be16()
>
> On Tue, Jun 25, 2019 at 11:44 AM David Laight <David.Laight@aculab.com> wrote:
> >
> > From: Dmitry Torokhov
> > > Sent: 23 June 2019 07:32
> > >
> > > Instead of doing conversion by hand, let's use the proper accessors.
> > >
> > > Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> > > ---
> > > drivers/input/touchscreen/edt-ft5x06.c | 5 +++--
> > > 1 file changed, 3 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/drivers/input/touchscreen/edt-ft5x06.c b/drivers/input/touchscreen/edt-ft5x06.c
> > > index c639ebce914c..ec770226e119 100644
> > > --- a/drivers/input/touchscreen/edt-ft5x06.c
> > > +++ b/drivers/input/touchscreen/edt-ft5x06.c
> > > @@ -27,6 +27,7 @@
> > > #include <linux/gpio/consumer.h>
> > > #include <linux/input/mt.h>
> > > #include <linux/input/touchscreen.h>
> > > +#include <asm/unaligned.h>
> > >
> > > #define WORK_REGISTER_THRESHOLD 0x00
> > > #define WORK_REGISTER_REPORT_RATE 0x08
> > > @@ -239,8 +240,8 @@ static irqreturn_t edt_ft5x06_ts_isr(int irq, void *dev_id)
> > > if (tsdata->version == EDT_M06 && type == TOUCH_EVENT_DOWN)
> > > continue;
> > >
> > > - x = ((buf[0] << 8) | buf[1]) & 0x0fff;
> > > - y = ((buf[2] << 8) | buf[3]) & 0x0fff;
> > > + x = get_unaligned_be16(buf) & 0x0fff;
> > > + y = get_unaligned_be16(buf + 2) & 0x0fff;
> >
> > You might as well delete the pointless masking with 0xff.
>
> Hmm... Does it guarantee the most significant nibble to be always 0?
> (Note 16-bit value and three f:s in the mask)

Sorry, I misread it :-(

David

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