Re: [PATCH 3/5] input: drv260x: Check the device ID at initialization

[Yauhen Kharuzhy]

On Thu, Feb 12, 2026 at 09:28:51AM -0800, Dmitry Torokhov wrote:
> On Thu, Feb 12, 2026 at 01:46:53AM +0200, Yauhen Kharuzhy wrote:
> > To ensure that the device is accessible on the I2C bus, read the status
> > register and check the Device ID field in drv260x_init().
> > 
> > Signed-off-by: Yauhen Kharuzhy <jekhor@xxxxxxxxx>
> > ---
> >  drivers/input/misc/drv260x.c | 44 ++++++++++++++++++++++++++++++++++++
> >  1 file changed, 44 insertions(+)
> > 
> > diff --git a/drivers/input/misc/drv260x.c b/drivers/input/misc/drv260x.c
> > index f613c81fa2ba..f08a3d6c3ed8 100644
> > --- a/drivers/input/misc/drv260x.c
> > +++ b/drivers/input/misc/drv260x.c
> > @@ -56,6 +56,13 @@
> >  #define DRV260X_LRA_RES_PERIOD	0x22
> >  #define DRV260X_MAX_REG			0x23
> >  
> > +#define DRV260X_STATUS_ID_MASK		0xe0
> > +#define DRV260X_STATUS_ID_SHIFT		5
> > +#define DRV260X_ID_DRV2605		3
> > +#define DRV260X_ID_DRV2604		4
> > +#define DRV260X_ID_DRV2604L		6
> > +#define DRV260X_ID_DRV2605L		7
> > +
> >  #define DRV260X_GO_BIT				0x01
> >  
> >  /* Library Selection */
> > @@ -305,10 +312,47 @@ static const struct reg_sequence drv260x_erm_cal_regs[] = {
> >  	{ DRV260X_CTRL4, DRV260X_AUTOCAL_TIME_500MS },
> >  };
> >  
> > +struct drv260x_id_map {
> > +	u8 id;
> > +	char *name;
> > +};
> > +
> > +static const struct drv260x_id_map drv_260x_devids[] = {
> > +	{ DRV260X_ID_DRV2605, "DRV2605"},
> > +	{ DRV260X_ID_DRV2604, "DRV2604"},
> > +	{ DRV260X_ID_DRV2604L, "DRV2604L"},
> > +	{ DRV260X_ID_DRV2605L, "DRV2605L"},
> > +};
> > +
> > +static char *drv260x_get_model(u8 id)
> > +{
> > +	int i;
> > +
> > +	for (i = 0; i < ARRAY_SIZE(drv_260x_devids); i++)
> > +		if (id == drv_260x_devids[i].id)
> > +			return drv_260x_devids[i].name;
> > +
> > +	return NULL;
> > +}
> > +
> >  static int drv260x_init(struct drv260x_data *haptics)
> >  {
> >  	int error;
> >  	unsigned int cal_buf;
> > +	u8 id;
> > +
> > +	error = regmap_read(haptics->regmap, DRV260X_STATUS, &cal_buf);
> > +	if (error) {
> > +		dev_err(&haptics->client->dev,
> > +				"Failed to read DRV260X_status register: %d\n",
> > +				error);
> > +		return error;
> > +	}
> > +
> > +	id = (cal_buf & DRV260X_STATUS_ID_MASK) >> DRV260X_STATUS_ID_SHIFT;
> > +
> > +	dev_info(&haptics->client->dev, "ID: %u (%s)\n", id,
> > +		 drv260x_get_model(id));
> >  
> >  	error = regmap_write(haptics->regmap,
> >  			     DRV260X_RATED_VOLT, haptics->rated_voltage);
> 
> If the device is not available this regmap_write() will fail so I am not
> sure why we need all this new code.

Mostly for informational purposes about the detected model. Maybe you are
right, and this is unnecessary.

> 
> Thanks.
> 
> -- 
> Dmitry

-- 
Yauhen Kharuzhy