linux-kernel - Re: [PATCH 1/2] Input: edt-ft5x06

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Date:   Tue, 25 Jun 2019 13:50:23 +0300
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     David Laight <David.Laight@...lab.com>
Cc:     Dmitry Torokhov <dmitry.torokhov@...il.com>,
        "linux-input@...r.kernel.org" <linux-input@...r.kernel.org>,
        Marco Felsch <m.felsch@...gutronix.de>,
        Benoit Parrot <bparrot@...com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.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@...lab.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@...il.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)


-- 
With Best Regards,
Andy Shevchenko