lkml.org 
[lkml]   [2012]   [Mar]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: Regulator supplies when using Device Tree
    On 3/28/2012 3:09 AM, Mark Brown wrote:
    > On Tue, Mar 27, 2012 at 06:38:30PM -0700, Michael Bohan wrote:
    >> the answer is that we should invent another binding to portray the
    >> name of the supply the driver should be checking against. But then
    >> it would seem silly to have two bindings that pertain to supply
    >> names.
    >
    > Absolutely not, that would be broken. The whole point here is that
    > supplies of all kinds are always requested with the name the chip uses
    > for the supply.

    Let's consider an example with two regulators:

    regulator@0 {
    compatible = "ldo_driver";
    foo-supply = <&smps1>;
    };

    regulator@1 {
    compatible = "ldo_driver";
    };

    How do we write a single regulator driver that supports both of these
    regulator devices?

    Within the regulator driver, we currently have to do an
    of_get_property(of_node, "foo-supply", NULL) to determine whether the
    device has a supply, and thus whether we should assign
    rdesc->supply_name to "foo" or not when calling regulator_register(). Is
    there a better way to do this? If we don't do this check for the case
    where a device does not have a supply specified in the Device Tree, then
    regulator_register() will fail.

    Before Device Tree, regulators could get their supply names directly
    from the board file like so:

    http://git.kernel.org/?p=linux/kernel/git/torvalds/linux.git;a=blob;f=Documentation/power/regulator/machine.txt;h=ce63af0a8e35ecab32e2f326d13a9a2b33b62909;hb=refs/heads/master#l67

    Thus the regulator driver was never concerned about the specifics of a
    supply name. And if the supply name was not specified, then the
    regulator_register() would happily succeed without any checks in the
    driver.

    Thanks,
    Mike

    --
    Sent by an employee of the Qualcomm Innovation Center, Inc.
    The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.


    \
     
     \ /
      Last update: 2012-03-28 21:21    [W:0.022 / U:60.732 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site