| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Date: Fri, 11 Mar 2011 15:45:39 +0100
From: Linus Walleij <linus.walleij@...aro.org>
To: Mark Brown <broonie@...nsource.wolfsonmicro.com>
Cc: Linus Walleij <linus.walleij@...ricsson.com>,
Liam Girdwood <lrg@...mlogic.co.uk>,
linux-kernel@...r.kernel.org, Lee Jones <lee.jones@...aro.org>
Subject: Re: [PATCH 1/4] regulator: add set_voltage_time[_sel] infrastructure
On Fri, Mar 11, 2011 at 1:25 PM, Mark Brown
<broonie@...nsource.wolfsonmicro.com> wrote:
> On Fri, Mar 11, 2011 at 11:54:28AM +0100, Linus Walleij wrote:
>
>> + /* Don't obtain this if it's not going to be used */
>> + if (rdev->desc->ops->set_voltage_time) {
>> + int old_voltage = -1;
>> +
>> + ret = _regulator_get_voltage(rdev);
>> + if (ret < 0)
>> + return ret;
>> + old_voltage = ret;
>> + /* Here we can figure out desired delay immediately */
>> + ret = rdev->desc->ops->set_voltage_time(rdev, old_voltage,
>> + min_uV, max_uV);
>
> I think this should be taking to as the argument rather than min and
> max. We're going to figure out an actual concrete voltage or selector
> during the set voltage process so there's no point in having to go
> through and pick a specific voltage twice. Actually, given that
> list_voltage() pretty much mandates selectors we can probably just only
> have a selector based version of this API then use the selector that got
> returned when we set the voltage.
So I remove some stuff and end up like this:
commit f33521d68746c0219d98e9b1f29b75966dabcbf2
Author: Linus Walleij <linus.walleij@...aro.org>
Date: Fri Mar 11 11:24:43 2011 +0100
regulator: add set_voltage_time_sel infrastructure
This makes it possible to set the stabilization time for voltage
regulators in the same manner as enable_time(). The interface
only supports regulators that implements fixed selectors.
Signed-off-by: Linus Walleij <linus.walleij@...aro.org>
diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index 9fa2095..569b198 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -1629,6 +1629,7 @@ static int _regulator_do_set_voltage(struct
regulator_dev *rdev,
int min_uV, int max_uV)
{
int ret;
+ int delay = 0;
unsigned int selector;
trace_regulator_set_voltage(rdev_get_name(rdev), min_uV, max_uV);
@@ -1662,6 +1663,22 @@ static int _regulator_do_set_voltage(struct
regulator_dev *rdev,
}
}
+ /*
+ * If we can't obtain the old selector there is not enough
+ * info to call set_voltage_time_sel().
+ */
+ if (rdev->desc->ops->set_voltage_time_sel &&
+ rdev->desc->ops->get_voltage_sel) {
+ unsigned int old_selector = 0;
+
+ ret = rdev->desc->ops->get_voltage_sel(rdev);
+ if (ret < 0)
+ return ret;
+ old_selector = ret;
+ delay = rdev->desc->ops->set_voltage_time_sel(rdev,
+ old_selector, selector);
+ }
+
if (best_val != INT_MAX) {
ret = rdev->desc->ops->set_voltage_sel(rdev, selector);
selector = best_val;
@@ -1672,6 +1689,14 @@ static int _regulator_do_set_voltage(struct
regulator_dev *rdev,
ret = -EINVAL;
}
+ /* Insert any necessary delays */
+ if (delay >= 1000) {
+ mdelay(delay / 1000);
+ udelay(delay % 1000);
+ } else if (delay) {
+ udelay(delay);
+ }
+
if (ret == 0)
_notifier_call_chain(rdev, REGULATOR_EVENT_VOLTAGE_CHANGE,
NULL);
diff --git a/include/linux/regulator/driver.h b/include/linux/regulator/driver.h
index b8ed16a..6c433b8 100644
--- a/include/linux/regulator/driver.h
+++ b/include/linux/regulator/driver.h
@@ -63,7 +63,11 @@ enum regulator_status {
* when running with the specified parameters.
*
* @enable_time: Time taken for the regulator voltage output voltage to
- * stabalise after being enabled, in microseconds.
+ * stabilise after being enabled, in microseconds.
+ * @set_voltage_time_sel: Time taken for the regulator voltage output voltage
+ * to stabilise after being set to a new value, in microseconds.
+ * The function provides the from and to voltage selector, the
+ * function should return the worst case.
*
* @set_suspend_voltage: Set the voltage for the regulator when the system
* is suspended.
@@ -103,8 +107,11 @@ struct regulator_ops {
int (*set_mode) (struct regulator_dev *, unsigned int mode);
unsigned int (*get_mode) (struct regulator_dev *);
- /* Time taken to enable the regulator */
+ /* Time taken to enable or set voltage on the regulator */
int (*enable_time) (struct regulator_dev *);
+ int (*set_voltage_time_sel) (struct regulator_dev *,
+ unsigned int old_selector,
+ unsigned int new_selector);
/* report regulator status ... most other accessors report
* control inputs, this reports results of combining inputs
(This is sufficient for us now anyway.)
> I also think we should be exporting this to consumers as things like
> cpufreq are interested in the latency for voltage changes.
Can we take that when we have a consumer that wants it? Looking
at it it becomes rather complex, since consumers don't know the
core-internal selectors, just discrete enumerated voltages, so these
have to be mapped back to selectors etc, that's pretty much ovehead
code that sits unused.
(If you insist, I will implement it.)
Linus Walleij
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists