Re: [PATCH v3 1/2] hwmon: (lm90) Add power control

[Mark Brown]

On Mon, Sep 09, 2013 at 06:29:11PM +0800, Wei Ni wrote:

> +	reg = devm_regulator_get_optional(dev, "vcc");
> +	if (!IS_ERR(reg)) {
> +		err = regulator_enable(reg);
> +		if (err < 0) {
> +			dev_err(&client->dev,
> +				"Failed to enable regulator: %d\n", err);
> +			return err;
> +		}
> +		msleep(25);
> +	} else {
> +		if (PTR_ERR(reg) == -EPROBE_DEFER)
> +			return -EPROBE_DEFER;
> +	}

This doesn't look good, it is going to ignore actual errors - I *really*
doubt that vcc is optional, it looks like it's the main power supply for
the device.  You should use normal regulator_get(), _optional() is for
supplies which could physically not be provided in a system (eg, if the
device can generate them internally if required).

Also do you really need 25ms after power on?

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