Re: [PATCH v2 1/4] hwmon: (adt7410) Don't re-read non-volatile registers

[Guenter Roeck <linux@roeck-us.net>]

On Mon, Feb 18, 2013 at 02:38:56PM +0100, Lars-Peter Clausen wrote:
> Currently each time the temperature register is read the driver also reads the
> threshold and hysteresis registers. This increases the amount of I2C traffic and
> time needed to read the temperature by a factor of ~5. Neither the threshold nor
> the hysteresis change on their own, so once we've read them, we should be able
> to just use the cached value of the registers. This patch modifies the code
> accordingly and only reads the threshold and hysteresis registers once during
> probe.
> 
> Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
> 
Just one comment (thanks to Hartmut), otherwise looks good.

> ---
> Changes since v1:
> 	* Fix error checking for i2c reads
> ---
[ ... ]

> +static int adt7410_fill_cache(struct i2c_client *client)
> +{
> +	struct adt7410_data *data = i2c_get_clientdata(client);
> +	int ret;
> +	int i;
> +
> +	for (i = 1; i < ARRAY_SIZE(ADT7410_REG_TEMP); i++) {
> +		ret = i2c_smbus_read_word_swapped(client, ADT7410_REG_TEMP[i]);
> +		if (ret < 0) {
> +			dev_dbg(&client->dev,
> +				"Failed to read value: reg %d, error %d\n",
> +				ADT7410_REG_TEMP[0], ret);

	ADT7410_REG_TEMP[i]

Thanks,
Guenter