On Thu, May 25, 2017 at 08:46:36PM +0300, Alex A. Mihaylov wrote:

This looks mostly fine, a couple of small things and like I said in
reply to Greg please use subject lines matching the style for the
subsystem - this makes it a lot easier for people to identify relevant
patches.

> +	int ret = -ENODEV;
> +
> +
> +	if (reg > 255)
> +		return -EINVAL;
> +
> +	mutex_lock(&sl->master->bus_mutex);
> +	if (!w1_reset_select_slave(sl)) {
> +		w1_write_8(sl->master, W1_CMD_READ_DATA);
> +		w1_write_8(sl->master, reg);
> +		*val = w1_read_8(sl->master);
> +		ret = 0;
> +	}
> +	mutex_unlock(&sl->master->bus_mutex);

This is a bit confusing with how -ENODEV is generated - move the
assignment into the if statement so it doesn't look like we're silently
ignoring errors unless you look back to the top of the function.

> +static struct regmap_bus regmap_w1_bus_a8_v16 = {
> +	.reg_read = w1_reg_a8_v16_read,
> +	.reg_write = w1_reg_a8_v16_write,
> +};

It'd be clearer to just have all all these structs at the end of the set
of functions rather than scattered about randomly.