From 3692db3a904800445f8af249e1ac0f2b6496f31d Mon Sep 17 00:00:00 2001 From: Laxman Dewangan Date: Wed, 1 Jul 2015 18:31:43 +0530 Subject: [PATCH] regulator: max8973: add support to configure ETR from DT The MAX8973/MAX77621 feature an Enhanced Transient Response(ETR) circuit that is enabled through software. The enhanced transient response reduces the voltage droop during large load steps by temporarily allowing all three phases to fire in unison, slewing total inductor current faster than would normally be possible if all three phases continued to operate 120deg out of phase. The enhanced transient response detector features two selectable sensitivity settings, which select the output voltage slew rate during load transients that triggers the ETR circuit. The sensitivity of the ETR detector is set by the CKADV[1:0] bits in the CONTROL2 register. Add support to configure the ETR through platform data from DT. Update the DT binding document accordingly. Signed-off-by: Laxman Dewangan Signed-off-by: Mark Brown --- .../bindings/regulator/max8973-regulator.txt | 6 ++++++ drivers/regulator/max8973-regulator.c | 19 +++++++++++++++++++ 2 files changed, 25 insertions(+) diff --git a/Documentation/devicetree/bindings/regulator/max8973-regulator.txt b/Documentation/devicetree/bindings/regulator/max8973-regulator.txt index 55efb24e5683..f80ea2fe27e6 100644 --- a/Documentation/devicetree/bindings/regulator/max8973-regulator.txt +++ b/Documentation/devicetree/bindings/regulator/max8973-regulator.txt @@ -25,6 +25,12 @@ Optional properties: -maxim,enable-frequency-shift: boolean, enable 9% frequency shift. -maxim,enable-bias-control: boolean, enable bias control. By enabling this startup delay can be reduce to 20us from 220us. +-maxim,enable-etr: boolean, enable Enhanced Transient Response. +-maxim,enable-high-etr-sensitivity: boolean, Enhanced transient response + circuit is enabled and set for high sensitivity. If this + property is available then etr will be enable default. + +Enhanced transient response (ETR) will affect the configuration of CKADV. Example: diff --git a/drivers/regulator/max8973-regulator.c b/drivers/regulator/max8973-regulator.c index e94ddcf97722..a8fd7f4dd8d8 100644 --- a/drivers/regulator/max8973-regulator.c +++ b/drivers/regulator/max8973-regulator.c @@ -421,6 +421,8 @@ static struct max8973_regulator_platform_data *max8973_parse_dt( struct device_node *np = dev->of_node; int ret; u32 pval; + bool etr_enable; + bool etr_sensitivity_high; pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL); if (!pdata) @@ -452,6 +454,23 @@ static struct max8973_regulator_platform_data *max8973_parse_dt( if (of_property_read_bool(np, "maxim,enable-bias-control")) pdata->control_flags |= MAX8973_CONTROL_BIAS_ENABLE; + etr_enable = of_property_read_bool(np, "maxim,enable-etr"); + etr_sensitivity_high = of_property_read_bool(np, + "maxim,enable-high-etr-sensitivity"); + if (etr_sensitivity_high) + etr_enable = true; + + if (etr_enable) { + if (etr_sensitivity_high) + pdata->control_flags |= + MAX8973_CONTROL_CLKADV_TRIP_75mV_PER_US; + else + pdata->control_flags |= + MAX8973_CONTROL_CLKADV_TRIP_150mV_PER_US; + } else { + pdata->control_flags |= MAX8973_CONTROL_CLKADV_TRIP_DISABLED; + } + return pdata; }