For some hardwares ramp_delay for BUCKs is a configurable parameter which can
be configured through DT or board file.This patch adds ramp_delay to regulator
constraints and allow user to configure it for regulators which supports this
feature, through DT or board file. It will provide two ways of setting the
ramp_delay for a regulator:
First, by setting it as constraints in board file(for configurable
regulators) and set_machine_constraints() will take care of setting it on
hardware by calling(the provided) .set_ramp_delay() operation(callback).
Second, by setting it as data in regulator_desc(as fixed/default
ramp_delay rate) for a regulator in driver.
regulator_set_voltage_time_sel() will give preference to
constraints->ramp_delay while reading ramp_delay rate for regulator. Similarly
users should also take care accordingly while refering ramp_delay rate(in case
of implementing their private .set_voltage_time_sel() callbacks for different
regulators).
Signed-off-by: Yadwinder Singh Brar <[email protected]>
---
.../devicetree/bindings/regulator/regulator.txt | 1 +
drivers/regulator/core.c | 23 ++++++++++++++++---
drivers/regulator/of_regulator.c | 6 ++++-
include/linux/regulator/driver.h | 3 ++
include/linux/regulator/machine.h | 3 ++
5 files changed, 31 insertions(+), 5 deletions(-)
diff --git a/Documentation/devicetree/bindings/regulator/regulator.txt b/Documentation/devicetree/bindings/regulator/regulator.txt
index 5b7a408..d0a7b12 100644
--- a/Documentation/devicetree/bindings/regulator/regulator.txt
+++ b/Documentation/devicetree/bindings/regulator/regulator.txt
@@ -10,6 +10,7 @@ Optional properties:
- regulator-always-on: boolean, regulator should never be disabled
- regulator-boot-on: bootloader/firmware enabled regulator
- <name>-supply: phandle to the parent supply/regulator node
+- regulator-ramp-delay: ramp delay for regulator(in mV/uS)
Example:
diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index 63507a5..0ffd917 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -967,6 +967,14 @@ static int set_machine_constraints(struct regulator_dev *rdev,
}
}
+ if (rdev->constraints->ramp_delay && ops->set_ramp_delay) {
+ ret = ops->set_ramp_delay(rdev, rdev->constraints->ramp_delay);
+ if (ret < 0) {
+ rdev_err(rdev, "failed to set ramp_delay\n");
+ goto out;
+ }
+ }
+
print_constraints(rdev);
return 0;
out:
@@ -2305,10 +2313,17 @@ int regulator_set_voltage_time_sel(struct regulator_dev *rdev,
unsigned int old_selector,
unsigned int new_selector)
{
- if (rdev->desc->ramp_delay && rdev->desc->uV_step)
- return DIV_ROUND_UP(rdev->desc->uV_step *
- abs(new_selector - old_selector),
- rdev->desc->ramp_delay * 1000);
+ if (rdev->desc->uV_step) {
+ if (rdev->constraints->ramp_delay)
+ return DIV_ROUND_UP(rdev->desc->uV_step *
+ abs(new_selector - old_selector),
+ rdev->constraints->ramp_delay * 1000);
+ if (rdev->desc->ramp_delay)
+ return DIV_ROUND_UP(rdev->desc->uV_step *
+ abs(new_selector - old_selector),
+ rdev->desc->ramp_delay * 1000);
+ rdev_warn(rdev, "ramp_delay not set\n");
+ }
return 0;
}
diff --git a/drivers/regulator/of_regulator.c b/drivers/regulator/of_regulator.c
index 56593b7..e2a7310 100644
--- a/drivers/regulator/of_regulator.c
+++ b/drivers/regulator/of_regulator.c
@@ -20,7 +20,7 @@ static void of_get_regulation_constraints(struct device_node *np,
struct regulator_init_data **init_data)
{
const __be32 *min_uV, *max_uV, *uV_offset;
- const __be32 *min_uA, *max_uA;
+ const __be32 *min_uA, *max_uA, *ramp_delay;
struct regulation_constraints *constraints = &(*init_data)->constraints;
constraints->name = of_get_property(np, "regulator-name", NULL);
@@ -60,6 +60,10 @@ static void of_get_regulation_constraints(struct device_node *np,
constraints->always_on = true;
else /* status change should be possible if not always on. */
constraints->valid_ops_mask |= REGULATOR_CHANGE_STATUS;
+
+ ramp_delay = of_get_property(np, "regulator-ramp-delay", NULL);
+ if (ramp_delay)
+ constraints->min_uV = be32_to_cpu(*ramp_delay);
}
/**
diff --git a/include/linux/regulator/driver.h b/include/linux/regulator/driver.h
index ae5c253..ddc155d 100644
--- a/include/linux/regulator/driver.h
+++ b/include/linux/regulator/driver.h
@@ -67,6 +67,8 @@ enum regulator_status {
*
* @enable_time: Time taken for the regulator voltage output voltage to
* stabilise after being enabled, in microseconds.
+ * @set_ramp_delay: Set the ramp delay for the regulator. The driver should
+ * select ramp delay equal to or less than(closest) ramp_delay.
* @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
@@ -113,6 +115,7 @@ struct regulator_ops {
/* Time taken to enable or set voltage on the regulator */
int (*enable_time) (struct regulator_dev *);
+ int (*set_ramp_delay) (struct regulator_dev *, int ramp_delay);
int (*set_voltage_time_sel) (struct regulator_dev *,
unsigned int old_selector,
unsigned int new_selector);
diff --git a/include/linux/regulator/machine.h b/include/linux/regulator/machine.h
index b021084..5f37ad3 100644
--- a/include/linux/regulator/machine.h
+++ b/include/linux/regulator/machine.h
@@ -92,6 +92,7 @@ struct regulator_state {
* mode.
* @initial_state: Suspend state to set by default.
* @initial_mode: Mode to set at startup.
+ * @ramp_delay: Time to settle down after voltage change (unit: mV/us)
*/
struct regulation_constraints {
@@ -125,6 +126,8 @@ struct regulation_constraints {
/* mode to set on startup */
unsigned int initial_mode;
+ unsigned int ramp_delay;
+
/* constraint flags */
unsigned always_on:1; /* regulator never off when system is on */
unsigned boot_on:1; /* bootloader/firmware enabled regulator */
--
1.7.0.4
On Mon, Jun 11, 2012 at 05:41:08PM +0530, Yadwinder Singh Brar wrote:
> For some hardwares ramp_delay for BUCKs is a configurable parameter which can
> be configured through DT or board file.This patch adds ramp_delay to regulator
> constraints and allow user to configure it for regulators which supports this
> feature, through DT or board file. It will provide two ways of setting the
> ramp_delay for a regulator:
Applied, thanks - sorry about the delay, you submitted the day before I
flew back from China. I rewrote the subject line to fit in 80 columns,
otherwise things like git log and pull requests look odd.