Re: [PATCH v2 1/5] Input: edt-ft5x06: work around first register access error

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On 19-12-02 09:58, Dmitry Torokhov wrote:
> On Wed, Nov 27, 2019 at 01:09:44PM +0100, Marco Felsch wrote:
> > From: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx>
> > 
> > The EP0700MLP1 returns bogus data on the first register read access
> > (reading the threshold parameter from register 0x00):
> > 
> >     edt_ft5x06 2-0038: crc error: 0xfc expected, got 0x40
> > 
> > It ignores writes until then. This patch adds a dummy read after which
> > the number of sensors and parameter read/writes work correctly.
> > 
> > Signed-off-by: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx>
> 
> Need your signed-off-by as well.

Damn, you're right.. I fix this in the next version.

> 
> > ---
> >  drivers/input/touchscreen/edt-ft5x06.c | 7 +++++++
> >  1 file changed, 7 insertions(+)
> > 
> > diff --git a/drivers/input/touchscreen/edt-ft5x06.c b/drivers/input/touchscreen/edt-ft5x06.c
> > index d61731c0037d..b87b1e074f62 100644
> > --- a/drivers/input/touchscreen/edt-ft5x06.c
> > +++ b/drivers/input/touchscreen/edt-ft5x06.c
> > @@ -1050,6 +1050,7 @@ static int edt_ft5x06_ts_probe(struct i2c_client *client,
> >  {
> >  	const struct edt_i2c_chip_data *chip_data;
> >  	struct edt_ft5x06_ts_data *tsdata;
> > +	u8 buf[2] = { 0xfc, 0x00 };
> >  	struct input_dev *input;
> >  	unsigned long irq_flags;
> >  	int error;
> > @@ -1140,6 +1141,12 @@ static int edt_ft5x06_ts_probe(struct i2c_client *client,
> >  		return error;
> >  	}
> >  
> > +	/*
> > +	 * Dummy read access. EP0700MLP1 returns bogus data on the first
> > +	 * register read access and ignores writes.
> > +	 */
> > +	edt_ft5x06_ts_readwrite(tsdata->client, 2, buf, 2, buf);
> > +
> >  	edt_ft5x06_ts_set_regs(tsdata);
> >  	edt_ft5x06_ts_get_defaults(&client->dev, tsdata);
> >  	edt_ft5x06_ts_get_parameters(tsdata);
> > -- 
> > 2.20.1
> > 
> 
> -- 
> Dmitry
> 

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