regulator: core: provide fixed voltage in desc for single voltage rail

If given rail has the single voltage (n_voltages = 1) then provide the
rail voltage through regulator descriptor so that core can use this
value for finding voltage.

This will avoid the implementation of the callback for get_voltage() or
list_voltage() callback on regulator driver.

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

2 files changed, 6 insertions, 1 deletions

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index a01b8b3b70ca..abc899ed1ebf 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -2489,6 +2489,8 @@ static int _regulator_get_voltage(struct regulator_dev *rdev)
                 ret = rdev->desc->ops->get_voltage(rdev);
         } else if (rdev->desc->ops->list_voltage) {
                 ret = rdev->desc->ops->list_voltage(rdev, 0);
+        } else if (rdev->desc->fixed_uV && (rdev->desc->n_voltages == 1)) {
+                ret = rdev->desc->fixed_uV;
         } else {
                 return -EINVAL;
         }
@@ -3170,7 +3172,8 @@ static int add_regulator_attributes(struct regulator_dev *rdev)
         /* some attributes need specific methods to be displayed */
         if ((ops->get_voltage && ops->get_voltage(rdev) >= 0) ||
             (ops->get_voltage_sel && ops->get_voltage_sel(rdev) >= 0) ||
-            (ops->list_voltage && ops->list_voltage(rdev, 0) >= 0)) {
+            (ops->list_voltage && ops->list_voltage(rdev, 0) >= 0) ||
+                (rdev->desc->fixed_uV && (rdev->desc->n_voltages == 1))) {
                 status = device_create_file(dev, &dev_attr_microvolts);
                 if (status < 0)
                         return status;
diff --git a/include/linux/regulator/driver.h b/include/linux/regulator/driver.h
index 67e13aa5a478..9e8241a9f28f 100644
--- a/include/linux/regulator/driver.h
+++ b/include/linux/regulator/driver.h
@@ -207,6 +207,7 @@ enum regulator_type {
  * @min_uV: Voltage given by the lowest selector (if linear mapping)
  * @uV_step: Voltage increase with each selector (if linear mapping)
  * @linear_min_sel: Minimal selector for starting linear mapping
+ * @fixed_uV: Fixed voltage of rails.
  * @ramp_delay: Time to settle down after voltage change (unit: uV/us)
  * @volt_table: Voltage mapping table (if table based mapping)
  *
@@ -239,6 +240,7 @@ struct regulator_desc {
         unsigned int min_uV;
         unsigned int uV_step;
         unsigned int linear_min_sel;
+        int fixed_uV;
         unsigned int ramp_delay;
 
         const struct regulator_linear_range *linear_ranges;