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Date: Tue, 16 May 2017 11:43:43 -0700 From: Matthias Kaehlcke <mka@...omium.org> To: Liam Girdwood <lgirdwood@...il.com>, Mark Brown <broonie@...nel.org>, Laxman Dewangan <ldewangan@...dia.com>, Rob Herring <robh+dt@...nel.org>, Mark Rutland <mark.rutland@....com> Cc: linux-kernel@...r.kernel.org, devicetree@...r.kernel.org, Douglas Anderson <dianders@...omium.org>, Brian Norris <briannorris@...omium.org>, Matthias Kaehlcke <mka@...omium.org> Subject: [PATCH v3 2/2] 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@...omium.org> Acked-by: Laxman Dewangan <ldewangan@...dia.com> --- Changes in v3: - Added check for conflicting settling time configurations. A warning is printed if up/down settling times are specified at the same time as the more general ("symmetrical") setting. In case of conflicts the up/down times are ignored and 'regulator-settling-time-us' is used. drivers/regulator/core.c | 6 ++++++ drivers/regulator/of_regulator.c | 19 +++++++++++++++++++ include/linux/regulator/machine.h | 6 ++++++ 3 files changed, 31 insertions(+) diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c index c0d9ae8d0860..919b7f178209 100644 --- 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 09d677d5d3f0..96bf75458da5 100644 --- 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 117699d1f7df..9cd4fef37203 100644 --- 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; -- 2.13.0.303.g4ebf302169-goog
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