From: linux@roeck-us•net (Guenter Roeck)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH 1/2] hwmon: (lm90) Add power control
Date: Wed, 07 Aug 2013 00:50:04 -0700 [thread overview]
Message-ID: <5201FC2C.4030908@roeck-us.net> (raw)
In-Reply-To: <5201F811.9050602@nvidia.com>
On 08/07/2013 12:32 AM, Wei Ni wrote:
> On 08/07/2013 03:27 PM, Alexander Shiyan wrote:
>>> 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@nvidia•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?
>
> I think it should be handled in the device driver.
> Because there have different delay time to wait devices stable.
>
Then why does no other caller of regulator_enable() need this ?
I don't think lm90 is so much different to other users of regulator
functionality.
Besides that, your delay is unconditional, even for static regulators
which are always on. Other callers of regulator_enable() don't need
all that complexity, which I take as sign that it is not needed here either.
Guenter
next prev parent reply other threads:[~2013-08-07 7:50 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-07 6:52 [PATCH 0/2] Add power control for lm90 Wei Ni
2013-08-07 6:52 ` [PATCH 1/2] hwmon: (lm90) Add power control Wei Ni
2013-08-07 7:03 ` Guenter Roeck
2013-08-07 7:15 ` Wei Ni
2013-08-07 7:27 ` Alexander Shiyan
2013-08-07 7:32 ` Wei Ni
2013-08-07 7:50 ` Guenter Roeck [this message]
2013-08-07 8:07 ` Wei Ni
2013-08-07 8:45 ` Alexander Shiyan
2013-08-07 9:35 ` Wei Ni
2013-08-07 16:06 ` Stephen Warren
2013-08-07 16:44 ` Guenter Roeck
2013-08-07 7:45 ` Guenter Roeck
2013-08-07 6:52 ` [PATCH 2/2] ARM: dt: t114 dalmore: add dt entry for nct1008 Wei Ni
2013-08-07 16:03 ` Stephen Warren
2013-08-08 2:36 ` Wei Ni
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