regulator: core: Add helpers for multiple linear ranges

Many regulators have several linear ranges of selector with different
step sizes, for example offering better resolution at lower voltages.
Provide regulator_{map,list}_voltage_linear_range() allowing these
regulators to use generic code. To do so a table of regulator_linear_range
structs needs to be pointed to from the descriptor.

This was inspired by similar code included in a driver submission from
Chao Xie and Yi Zhang at Marvell.

Signed-off-by: Mark Brown <broonie@linaro.org>

1 files changed, 25 insertions, 0 deletions

diff --git a/include/linux/regulator/driver.h b/include/linux/regulator/driver.h
index 6700cc94bdd1..67e13aa5a478 100644
--- a/include/linux/regulator/driver.h
+++ b/include/linux/regulator/driver.h
@@ -40,6 +40,24 @@ enum regulator_status {
 };
 
 /**
+ * Specify a range of voltages for regulator_map_linar_range() and
+ * regulator_list_linear_range().
+ *
+ * @min_uV:  Lowest voltage in range
+ * @max_uV:  Highest voltage in range
+ * @min_sel: Lowest selector for range
+ * @max_sel: Highest selector for range
+ * @uV_step: Step size
+ */
+struct regulator_linear_range {
+        unsigned int min_uV;
+        unsigned int max_uV;
+        unsigned int min_sel;
+        unsigned int max_sel;
+        unsigned int uV_step;
+};
+
+/**
  * struct regulator_ops - regulator operations.
  *
  * @enable: Configure the regulator as enabled.
@@ -223,6 +241,9 @@ struct regulator_desc {
         unsigned int linear_min_sel;
         unsigned int ramp_delay;
 
+        const struct regulator_linear_range *linear_ranges;
+        int n_linear_ranges;
+
         const unsigned int *volt_table;
 
         unsigned int vsel_reg;
@@ -326,10 +347,14 @@ int regulator_mode_to_status(unsigned int);
 
 int regulator_list_voltage_linear(struct regulator_dev *rdev,
                                   unsigned int selector);
+int regulator_list_voltage_linear_range(struct regulator_dev *rdev,
+                                        unsigned int selector);
 int regulator_list_voltage_table(struct regulator_dev *rdev,
                                   unsigned int selector);
 int regulator_map_voltage_linear(struct regulator_dev *rdev,
                                   int min_uV, int max_uV);
+int regulator_map_voltage_linear_range(struct regulator_dev *rdev,
+                                       int min_uV, int max_uV);
 int regulator_map_voltage_iterate(struct regulator_dev *rdev,
                                   int min_uV, int max_uV);
 int regulator_map_voltage_ascend(struct regulator_dev *rdev,