RE: [PATCH 01/13] OMAP: Introduce a user list for each voltage domain instance in the voltage driver.

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 




>>-----Original Message-----
>>From: Kevin Hilman [mailto:khilman@xxxxxxxxxxxxxxxxxxx]
>>Sent: Thursday, September 02, 2010 4:22 AM
>>To: Gopinath, Thara
>>Cc: linux-omap@xxxxxxxxxxxxxxx; paul@xxxxxxxxx; Sripathy, Vishwanath; Sawant, Anand; Cousson, Benoit;
>>thomas.petazzoni@xxxxxxxxxxxxxxxxxx
>>Subject: Re: [PATCH 01/13] OMAP: Introduce a user list for each voltage domain instance in the
>>voltage driver.
>>
>>Thara Gopinath <thara@xxxxxx> writes:
>>
>>> This patch introduces a user list of devices associated with each
>>> voltage domain instance. The user list is implemented using plist
>>> structure with priority node populated with the voltage values.
>>> This patch also adds an API which will take in a device and
>>> requested voltage as parameters, adds the info to the user list
>>> and returns back the maximum voltage requested by all the user
>>> devices. This can be used anytime to get the voltage that the
>>> voltage domain instance can be transitioned into.
>>>
>>> Signed-off-by: Thara Gopinath <thara@xxxxxx>
>>
>>Looking closer at this, keeping track of a list of devices and
>>constraints is what the regulator framework does as well.
>>
>>Before we get too far down this path, we need to start working with
>>Thomas Petazzoni to better understand how we can use the regulator
>>framework for much of the management levels of the voltage layer.
>>
>>I'd rather not re-invent some of the management/constraints management
>>that could be done by the regulator framework.
>>
>>Basically, I think
>>
>>  r = regulator_get(dev, voltdm->name)
>>  regulator_set_voltage(r, volt)
>>
>>would basially be the equivalent of
>>
>>  omap_voltage_add_userreq(voldm, dev, &volt);
>>  omap_scale_voltage(voltdm, volt)

Hello Kevin,

Let me startr off by saying that I am not an expert on regulator
framework and hence my assessment below could be wrong.
I agree probably regulator framework would be 
the best place for this but then IMO regulator framework needs a lot of
changes to support the kind of use-counting we need in the voltage layer.
To start with regulator_get  keeps the use counting only for enabling or
disabling a regulator. It does not have a mechanism of adding the requested
voltage to a list and picking out the highest among the added values.
regulator_set_voltage could be used to route the call to omap_scale_voltage
but then it is just a wrapper.

Regards
Thara
--
To unsubscribe from this list: send the line "unsubscribe linux-omap" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html


[Index of Archives]     [Linux Arm (vger)]     [ARM Kernel]     [ARM MSM]     [Linux Tegra]     [Linux WPAN Networking]     [Linux Wireless Networking]     [Maemo Users]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite Trails]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux