regulator: Allow for asymmetric settling times

Some regulators have different settling times for voltage increases and
decreases. To avoid a time penalty on the faster transition allow for
different settings for up- and downward transitions.

Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
Acked-by: Laxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index c0d9ae8d0860e8e9466dee6fe1e275853b1f9e3b..919b7f1782091ba2da18117db77288124e4f5924 100644 (file)
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -2767,6 +2767,12 @@ static int _regulator_set_voltage_time(struct regulator_dev *rdev,
                ramp_delay = rdev->desc->ramp_delay;
        else if (rdev->constraints->settling_time)
                return rdev->constraints->settling_time;
+       else if (rdev->constraints->settling_time_up &&
+                (new_uV > old_uV))
+               return rdev->constraints->settling_time_up;
+       else if (rdev->constraints->settling_time_down &&
+                (new_uV < old_uV))
+               return rdev->constraints->settling_time_down;
 
        if (ramp_delay == 0) {
                rdev_dbg(rdev, "ramp_delay not set\n");

diff --git a/drivers/regulator/of_regulator.c b/drivers/regulator/of_regulator.c
index 09d677d5d3f02b6dea295c8379df2cc03d8e8577..96bf75458da5101ada4321609635933ed715f338 100644 (file)
--- a/drivers/regulator/of_regulator.c
+++ b/drivers/regulator/of_regulator.c
@@ -90,6 +90,25 @@ static void of_get_regulation_constraints(struct device_node *np,
        if (!ret)
                constraints->settling_time = pval;
 
+       ret = of_property_read_u32(np, "regulator-settling-time-up-us", &pval);
+       if (!ret)
+               constraints->settling_time_up = pval;
+       if (constraints->settling_time_up && constraints->settling_time) {
+               pr_warn("%s: ambiguous configuration for settling time, ignoring 'regulator-settling-time-up-us'\n",
+                       np->name);
+               constraints->settling_time_up = 0;
+       }
+
+       ret = of_property_read_u32(np, "regulator-settling-time-down-us",
+                                  &pval);
+       if (!ret)
+               constraints->settling_time_down = pval;
+       if (constraints->settling_time_down && constraints->settling_time) {
+               pr_warn("%s: ambiguous configuration for settling time, ignoring 'regulator-settling-time-down-us'\n",
+                       np->name);
+               constraints->settling_time_down = 0;
+       }
+
        ret = of_property_read_u32(np, "regulator-enable-ramp-delay", &pval);
        if (!ret)
                constraints->enable_time = pval;

diff --git a/include/linux/regulator/machine.h b/include/linux/regulator/machine.h
index 117699d1f7df4f72491bd65eccec39a160acf646..9cd4fef37203cbdc8fc76a07a1d81334acc789d3 100644 (file)
--- a/include/linux/regulator/machine.h
+++ b/include/linux/regulator/machine.h
@@ -110,6 +110,10 @@ struct regulator_state {
  * @ramp_delay: Time to settle down after voltage change (unit: uV/us)
  * @settling_time: Time to settle down after voltage change when voltage
  *                change is non-linear (unit: microseconds).
+ * @settling_time_up: Time to settle down after voltage increase when voltage
+ *                   change is non-linear (unit: microseconds).
+ * @settling_time_down : Time to settle down after voltage decrease when
+ *                      voltage change is non-linear (unit: microseconds).
  * @active_discharge: Enable/disable active discharge. The enum
  *                   regulator_active_discharge values are used for
  *                   initialisation.
@@ -152,6 +156,8 @@ struct regulation_constraints {
 
        unsigned int ramp_delay;
        unsigned int settling_time;
+       unsigned int settling_time_up;
+       unsigned int settling_time_down;
        unsigned int enable_time;
 
        unsigned int active_discharge;