regulator: max8973: add support to configure ETR based on rail load

Add support to configure Enhanced Transient Response Enable (ETR)
and Sensitivity Selection based on maximum current on that rail i.e.
expected load on that rail.

The 75mV/us setting recommended for 0 to 9A expected loads, The
150mV/ìs setting recommended for 9A to 12A expected loads.
Disabling ETR is recommended for loads >12A.

bug 200116080

Change-Id: Ie4d92fd8c17ba183591a9fe9e8b24b0fcb4ba988
Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
(cherry picked from commit 78cfe09ca2d67e863355757ebbb595354ce5cd7f)
Reviewed-on: http://git-master/r/761656

diff --git a/drivers/regulator/max8973-regulator.c b/drivers/regulator/max8973-regulator.c
index c9b9bad33f3f69921c3f3dc3abfb8be7166ba371..3f754586457656e96fdd0350d26027c84df4f764 100644 (file)
--- a/drivers/regulator/max8973-regulator.c
+++ b/drivers/regulator/max8973-regulator.c
@@ -81,6 +81,7 @@
 #define MAX8973_FT_ENABLE                              BIT(4)
 #define MAX77621_T_JUNCTION_120                                BIT(7)
 
+#define MAX8973_CKKADV_TRIP_MASK                       0xC
 #define MAX8973_CKKADV_TRIP_DISABLE                    0xC
 #define MAX8973_CKKADV_TRIP_75mV_PER_US                        0x0
 #define MAX8973_CKKADV_TRIP_150mV_PER_US               0x4
@@ -322,6 +323,55 @@ static int max8973_set_ramp_delay(struct regulator_dev *rdev,
        return ret_val;
 }
 
+static int max8973_set_current_limit(struct regulator_dev *rdev,
+               int min_ua, int max_ua)
+{
+       struct max8973_chip *max = rdev_get_drvdata(rdev);
+       unsigned int val;
+       int ret;
+
+       if (max_ua <= 9000000)
+               val = MAX8973_CKKADV_TRIP_75mV_PER_US;
+       else if (max_ua <= 12000000)
+               val = MAX8973_CKKADV_TRIP_150mV_PER_US;
+       else
+               val = MAX8973_CKKADV_TRIP_DISABLE;
+
+       ret = regmap_update_bits(max->regmap, MAX8973_CONTROL2,
+                       MAX8973_CKKADV_TRIP_MASK, val);
+       if (ret < 0) {
+               dev_err(max->dev, "register %d update failed: %d\n",
+                               MAX8973_CONTROL2, ret);
+               return ret;
+       }
+       return 0;
+}
+
+static int max8973_get_current_limit(struct regulator_dev *rdev)
+{
+       struct max8973_chip *max = rdev_get_drvdata(rdev);
+       unsigned int control2;
+       int ret;
+
+       ret = regmap_read(max->regmap, MAX8973_CONTROL2, &control2);
+       if (ret < 0) {
+               dev_err(max->dev, "register %d read failed: %d\n",
+                               MAX8973_CONTROL2, ret);
+               return ret;
+       }
+       switch (control2 & MAX8973_CKKADV_TRIP_MASK) {
+       case MAX8973_CKKADV_TRIP_DISABLE:
+               return 15000000;
+       case MAX8973_CKKADV_TRIP_150mV_PER_US:
+               return 12000000;
+       case MAX8973_CKKADV_TRIP_75mV_PER_US:
+               return 9000000;
+       default:
+               break;
+       }
+       return 9000000;
+}
+
 static const struct regulator_ops max8973_dcdc_ops = {
        .get_voltage_sel        = max8973_dcdc_get_voltage_sel,
        .set_voltage_sel        = max8973_dcdc_set_voltage_sel,
@@ -331,6 +381,8 @@ static const struct regulator_ops max8973_dcdc_ops = {
        .set_voltage_time_sel   = regulator_set_voltage_time_sel,
        .set_ramp_delay         = max8973_set_ramp_delay,
        .set_sleep_voltage_sel  = max8973_dcdc_set_sleep_voltage_sel,
+       .set_current_limit      = max8973_set_current_limit,
+       .get_current_limit      = max8973_get_current_limit,
 };
 
 static int max8973_init_dcdc(struct max8973_chip *max,