Hi,

On 09/21/2014 05:01 AM, Matt Ranostay wrote:

 	priv->regmap = devm_regmap_init_i2c(i2c_client, &cap1106_regmap_config);
 	if (IS_ERR(priv->regmap))
 		return PTR_ERR(priv->regmap);
 
-	error = regmap_read(priv->regmap, CAP1106_REG_PRODUCT_ID, &val);
-	if (error)
-		return error;
-
-	if (val != CAP1106_PRODUCT_ID) {
-		dev_err(dev, "Product ID: Got 0x%02x, expected 0x%02x\n",
-			val, CAP1106_PRODUCT_ID);
-		return -ENODEV;
-	}
-

Btw - the purpose of this code was to detect board configuration
mismatch. After all, I2C lacks a way to properly identify peripherals,
so the more runtime checks we do at probe time, the more of a chance we
have to detect wrong setups. This device is actually well implemented
and tells us something about itself.

Hence, I'd propose to define a structure like this:

struct cap11xx_hw_model {
	uint8_t product_id;
	unsigned int num_channels;
};

... and attach instances of that to the members of cap1106_dt_ids[] and
cap1106_i2c_ids[]. In the probe function, check that the contents of
CAP1106_PRODUCT_ID match what is expected by the configured model.


Thanks,
Daniel