Re: [PATCH v1 04/63] Input: atmel_mxt_ts - split large i2c transfers into blocks

[Jiada Wang]

Hi Dmitry

On 2019/08/17 2:18, Dmitry Torokhov wrote:
> On Fri, Aug 16, 2019 at 05:28:53PM +0900, Jiada Wang wrote:
> > From: Nick Dyer <nick.dyer@xxxxxxxxxxx>
> >
> > On some firmware variants, the size of the info block exceeds what can
> > be read in a single transfer.
> >
> > Signed-off-by: Nick Dyer <nick.dyer@xxxxxxxxxxx>
> > (cherry picked from ndyer/linux/for-upstream commit 74c4f5277cfa403d43fafc404119dc57a08677db)
> > [gdavis: Forward port and fix conflicts due to v4.14.51 commit
> > 	 960fe000b1d3 ("Input: atmel_mxt_ts - fix the firmware
> > 	 update").]
> > Signed-off-by: George G. Davis <george_davis@xxxxxxxxxx>
> > Signed-off-by: Jiada Wang <jiada_wang@xxxxxxxxxx>
> > ---
> >   drivers/input/touchscreen/atmel_mxt_ts.c | 27 +++++++++++++++++++++---
> >   1 file changed, 24 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c b/drivers/input/touchscreen/atmel_mxt_ts.c
> > index 9b165d23e092..2d70ddf71cd9 100644
> > --- a/drivers/input/touchscreen/atmel_mxt_ts.c
> > +++ b/drivers/input/touchscreen/atmel_mxt_ts.c
> > @@ -40,7 +40,7 @@
> >   #define MXT_OBJECT_START	0x07
> >   #define MXT_OBJECT_SIZE		6
> >   #define MXT_INFO_CHECKSUM_SIZE	3
> > -#define MXT_MAX_BLOCK_WRITE	256
> > +#define MXT_MAX_BLOCK_WRITE	255
> >   
> >   /* Object types */
> >   #define MXT_DEBUG_DIAGNOSTIC_T37	37
> > @@ -659,6 +659,27 @@ static int __mxt_read_reg(struct i2c_client *client,
> >   	return ret;
> >   }
> >   
> > +static int mxt_read_blks(struct mxt_data *data, u16 start, u16 count, u8 *buf)
>
> Can we call this __mxt_read_reg() and the original read reg call
> __mxt_read_chunk()?
yes, I will update in v2 patch-set,
so that every call to __mxt_read_reg() in atmel driver,
can have the feature to split large size transfer.

Thanks,
Jiada

> > +{
> > +	u16 offset = 0;
> > +	int error;
> > +	u16 size;
> > +
> > +	while (offset < count) {
> > +		size = min(MXT_MAX_BLOCK_WRITE, count - offset);
> > +
> > +		error = __mxt_read_reg(data->client,
> > +				       start + offset,
> > +				       size, buf + offset);
> > +		if (error)
> > +			return error;
> > +
> > +		offset += size;
> > +	}
> > +
> > +	return 0;
> > +}
>
> Thanks.