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

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

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@gmail.com>
> ---
>  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.

Thanks.

-- 
Dmitry