linux-kernel - Re: [PATCH 1/2] hwmon: (lm90) Add power control

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Date:	Wed, 07 Aug 2013 11:27:22 +0400
From:	Alexander Shiyan <shc_work@...l.ru>
To:	Wei Ni <wni@...dia.com>
Cc:	khali@...ux-fr.org, swarren@...dotorg.org,
	linux-kernel@...r.kernel.org, lm-sensors@...sensors.org,
	MLongnecker@...dia.com, linux@...ck-us.net,
	linux-tegra@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH 1/2] hwmon: (lm90) Add power control

> The device lm90 can be controlled by the vdd rail.
> Adding the power control support to power on/off the vdd rail.
> And make sure that power is enabled before accessing the device.
> 
> Signed-off-by: Wei Ni <wni@...dia.com>
> ---
>  drivers/hwmon/lm90.c |   52 ++++++++++++++++++++++++++++++++++++++++++++++++++
[...]
> +	if (!data->lm90_reg) {
> +		data->lm90_reg = regulator_get(&client->dev, "vdd");
> +		if (IS_ERR_OR_NULL(data->lm90_reg)) {
> +			if (PTR_ERR(data->lm90_reg) == -ENODEV)
> +				dev_info(&client->dev,
> +					 "No regulator found for vdd. Assuming vdd is always powered.");
> +			else
> +				dev_warn(&client->dev,
> +					 "Error [%ld] in getting the regulator handle for vdd.\n",
> +					 PTR_ERR(data->lm90_reg));
> +			data->lm90_reg = NULL;
> +			mutex_unlock(&data->update_lock);
> +			return -ENODEV;
> +		}
> +	}
> +	if (is_enable) {
> +		ret = regulator_enable(data->lm90_reg);
> +		msleep(POWER_ON_DELAY);

Can this delay be handled directly from regulator?

[...]
---