2012-06-14 22:07:11

by Philip Rakity

[permalink] [raw]
Subject: [PATCH 1/2] regulator: core.c Pass voltage to notifier when setting voltage

V2
--

Incorporate performance suggestions made by Mark Brown
Use linux-next as base code rather than mmc-next

The voltage being set should be passed to the handler requesting
the callback. Currently this is not done.

The callback cannot call regulator_get_voltage() to get the
information since the mutex is held by the regulator and
deadlock occurs.

Without this change the receiver of the notify cannot now what
action to take. This is used, for example, to set PAD voltages
when doing SD vccq voltage changes.

Signed-off-by: Philip Rakity <[email protected]>
---
drivers/regulator/core.c | 6 +++---
1 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index 63507a5..5b04916 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -2153,7 +2153,7 @@ static int _regulator_do_set_voltage(struct regulator_dev *rdev,
if (rdev->desc->ops->list_voltage)
best_val = rdev->desc->ops->list_voltage(rdev, selector);
else
- best_val = -1;
+ best_val = _regulator_get_voltage(rdev);

/* Call set_voltage_time_sel if successfully obtained old_selector */
if (_regulator_is_enabled(rdev) && ret == 0 && old_selector >= 0 &&
@@ -2176,9 +2176,9 @@ static int _regulator_do_set_voltage(struct regulator_dev *rdev,
udelay(delay);
}

- if (ret == 0)
+ if (ret == 0 && best_val >= 0)
_notifier_call_chain(rdev, REGULATOR_EVENT_VOLTAGE_CHANGE,
- NULL);
+ (void *)best_val);

trace_regulator_set_voltage_complete(rdev_get_name(rdev), best_val);

--
1.7.0.4


2012-06-15 18:08:15

by Mark Brown

[permalink] [raw]
Subject: Re: [PATCH 1/2] regulator: core.c Pass voltage to notifier when setting voltage

On Fri, Jun 15, 2012 at 11:28:38PM +0530, Pankaj Jangra wrote:

> I am also curious to know if you pass the voltage here to notifier call
> how does it make any difference, since in
> blocking_notifier_call_chain() again passes the NULL. So does your patch
> should modify the arguments to this function also?
> Please let me know if i am missing something in understanding.

Your mail would have been rather more comprehensible if you'd mentioned
that you were talking about the call in _blocking_notifier_call_chain()
(which is obviously buggy).


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