regulator: max8973: add support to configure ETR based on rail load
authorLaxman Dewangan <ldewangan@nvidia.com>
Wed, 1 Jul 2015 13:01:44 +0000 (18:31 +0530)
committerMark Brown <broonie@kernel.org>
Tue, 7 Jul 2015 13:43:53 +0000 (14:43 +0100)
Add support to configure Enhanced Transient Response Enable (ETR)
and Sensitivity Selection based on maximum current i.e. expected
load on that rail.

Maxim recommended as:
- Enable ETR with high sensitivity (75mV/us) for 0 to 9A expected loads,
- Enable ETR with low sensitivity (150mV/us) for 9A to 12A expected loads.
- Disable ETR for expected load > 12A.

These recommendation will be configured for MAX77621 when maximum load
is provided through regulator constraint for maximum current from platform.

Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
drivers/regulator/max8973-regulator.c

index a8fd7f4..f673659 100644 (file)
@@ -75,6 +75,7 @@
 #define MAX8973_DISCH_ENBABLE                          BIT(5)
 #define MAX8973_FT_ENABLE                              BIT(4)
 
+#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
@@ -282,6 +283,55 @@ static int max8973_set_ramp_delay(struct regulator_dev *rdev,
        return ret;
 }
 
+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,
@@ -632,6 +682,8 @@ static int max8973_probe(struct i2c_client *client,
                max->ops.enable = regulator_enable_regmap;
                max->ops.disable = regulator_disable_regmap;
                max->ops.is_enabled = regulator_is_enabled_regmap;
+               max->ops.set_current_limit = max8973_set_current_limit;
+               max->ops.get_current_limit = max8973_get_current_limit;
                break;
        default:
                break;