regulator: max8973: add mechanism to enable/disable through GPIO

MAX8973 supports the voltage output enable/disable through its EN
pin. This EN pin can be connected through GPIO from host processor.
Add support to provide GPIO number from platform/DT and if it is
valid GPIO then enable external control default.

Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/Documentation/devicetree/bindings/regulator/max8973-regulator.txt b/Documentation/devicetree/bindings/regulator/max8973-regulator.txt
index f63de7d8dc23eb108e390e3aaf90f1bcc3881e02..201a26337387b541a1f262251b1f678cd3da284f 100644 (file)
--- a/Documentation/devicetree/bindings/regulator/max8973-regulator.txt
+++ b/Documentation/devicetree/bindings/regulator/max8973-regulator.txt
@@ -12,6 +12,8 @@ Optional properties:
 
 -maxim,externally-enable: boolean, externally control the regulator output
                enable/disable.
+-maxim,enable-gpio: GPIO for enable control. If the valid GPIO is provided
+               then externally enable control will be considered.
 -maxim,dvs-gpio: GPIO which is connected to DVS pin of device.
 -maxim,dvs-default-state: Default state of GPIO during initialisation.
                1 for HIGH and 0 for LOW.

diff --git a/drivers/regulator/max8973-regulator.c b/drivers/regulator/max8973-regulator.c
index 1442f920c80e34e1a4ca27bef68c4ea3ce971968..00cf91cc4c855538c850c67e5e35642e369bbeab 100644 (file)
--- a/drivers/regulator/max8973-regulator.c
+++ b/drivers/regulator/max8973-regulator.c
@@ -96,6 +96,7 @@ struct max8973_chip {
        struct regulator_desc desc;
        struct regmap *regmap;
        bool enable_external_control;
+       int enable_gpio;
        int dvs_gpio;
        int lru_index[MAX8973_MAX_VOUT_REG];
        int curr_vout_val[MAX8973_MAX_VOUT_REG];
@@ -379,6 +380,7 @@ static struct max8973_regulator_platform_data *max8973_parse_dt(
 
        pdata->enable_ext_control = of_property_read_bool(np,
                                                "maxim,externally-enable");
+       pdata->enable_gpio = of_get_named_gpio(np, "maxim,enable-gpio", 0);
        pdata->dvs_gpio = of_get_named_gpio(np, "maxim,dvs-gpio", 0);
 
        ret = of_property_read_u32(np, "maxim,dvs-default-state", &pval);
@@ -409,6 +411,7 @@ static int max8973_probe(struct i2c_client *client,
                         const struct i2c_device_id *id)
 {
        struct max8973_regulator_platform_data *pdata;
+       struct regulator_init_data *ridata;
        struct regulator_config config = { };
        struct regulator_dev *rdev;
        struct max8973_chip *max;
@@ -427,7 +430,8 @@ static int max8973_probe(struct i2c_client *client,
                return -EIO;
        }
 
-       if (pdata->dvs_gpio == -EPROBE_DEFER)
+       if ((pdata->dvs_gpio == -EPROBE_DEFER) ||
+               (pdata->enable_gpio == -EPROBE_DEFER))
                return -EPROBE_DEFER;
 
        max = devm_kzalloc(&client->dev, sizeof(*max), GFP_KERNEL);
@@ -453,6 +457,15 @@ static int max8973_probe(struct i2c_client *client,
        max->desc.uV_step = MAX8973_VOLATGE_STEP;
        max->desc.n_voltages = MAX8973_BUCK_N_VOLTAGE;
 
+       max->dvs_gpio = (pdata->dvs_gpio) ? pdata->dvs_gpio : -EINVAL;
+       max->enable_gpio = (pdata->enable_gpio) ? pdata->enable_gpio : -EINVAL;
+       max->enable_external_control = pdata->enable_ext_control;
+       max->curr_gpio_val = pdata->dvs_def_state;
+       max->curr_vout_reg = MAX8973_VOUT + pdata->dvs_def_state;
+
+       if (gpio_is_valid(max->enable_gpio))
+               max->enable_external_control = true;
+
        if (!pdata->enable_ext_control) {
                max->desc.enable_reg = MAX8973_VOUT;
                max->desc.enable_mask = MAX8973_VOUT_ENABLE;
@@ -461,11 +474,6 @@ static int max8973_probe(struct i2c_client *client,
                max->ops.is_enabled = regulator_is_enabled_regmap;
        }
 
-       max->dvs_gpio = (pdata->dvs_gpio) ? pdata->dvs_gpio : -EINVAL;
-       max->enable_external_control = pdata->enable_ext_control;
-       max->curr_gpio_val = pdata->dvs_def_state;
-       max->curr_vout_reg = MAX8973_VOUT + pdata->dvs_def_state;
-
        max->lru_index[0] = max->curr_vout_reg;
 
        if (gpio_is_valid(max->dvs_gpio)) {
@@ -509,6 +517,15 @@ static int max8973_probe(struct i2c_client *client,
        config.of_node = client->dev.of_node;
        config.regmap = max->regmap;
 
+       if (gpio_is_valid(max->enable_gpio)) {
+               ridata = pdata->reg_init_data;
+               config.ena_gpio_flags = GPIOF_OUT_INIT_LOW;
+               if (ridata && (ridata->constraints.always_on ||
+                       ridata->constraints.boot_on))
+                       config.ena_gpio_flags = GPIOF_OUT_INIT_HIGH;
+               config.ena_gpio = max->enable_gpio;
+       }
+
        /* Register the regulators */
        rdev = devm_regulator_register(&client->dev, &max->desc, &config);
        if (IS_ERR(rdev)) {

diff --git a/include/linux/regulator/max8973-regulator.h b/include/linux/regulator/max8973-regulator.h
index f8acc052e35326ebc818809bc921896c81c7fd02..f6a8a16a0d4deb27dc232f782a13453a5ba73ce0 100644 (file)
--- a/include/linux/regulator/max8973-regulator.h
+++ b/include/linux/regulator/max8973-regulator.h
@@ -58,6 +58,9 @@
  *             control signal from EN input pin. If it is false then
  *             voltage output will be enabled/disabled through EN bit of
  *             device register.
+ * @enable_gpio: Enable GPIO. If EN pin is controlled through GPIO from host
+ *             then GPIO number can be provided. If no GPIO controlled then
+ *             it should be -1.
  * @dvs_gpio: GPIO for dvs. It should be -1 if this is tied with fixed logic.
  * @dvs_def_state: Default state of dvs. 1 if it is high else 0.
  */
@@ -65,6 +68,7 @@ struct max8973_regulator_platform_data {
        struct regulator_init_data *reg_init_data;
        unsigned long control_flags;
        bool enable_ext_control;
+       int enable_gpio;
        int dvs_gpio;
        unsigned dvs_def_state:1;
 };