regulator: core: Support bypass mode

Many regulators support a bypass mode where they simply switch their
input supply to the output. This is mainly used in low power retention
states where power consumption is extremely low so higher voltage or
less clean supplies can be used.

Support this by providing ops for the drivers and a consumer API which
allows the device to be put into bypass mode if all consumers enable it
and the machine enables permission for this.

This is not supported as a mode since the existing modes are rarely used
due to fuzzy definition and mostly redundant with modern hardware which is
able to respond promptly to load changes.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Reviewed-by: Graeme Gregory <gg@slimlogic.co.uk>

3 files changed, 20 insertions, 0 deletions

diff --git a/include/linux/regulator/consumer.h b/include/linux/regulator/consumer.h
index da339fd8c75..ea3e3581662 100644
--- a/include/linux/regulator/consumer.h
+++ b/include/linux/regulator/consumer.h
@@ -177,6 +177,8 @@ int regulator_set_mode(struct regulator *regulator, unsigned int mode);
 unsigned int regulator_get_mode(struct regulator *regulator);
 int regulator_set_optimum_mode(struct regulator *regulator, int load_uA);
 
+int regulator_allow_bypass(struct regulator *regulator, bool allow);
+
 /* regulator notifier block */
 int regulator_register_notifier(struct regulator *regulator,
 			      struct notifier_block *nb);
@@ -328,6 +330,12 @@ static inline int regulator_set_optimum_mode(struct regulator *regulator,
 	return REGULATOR_MODE_NORMAL;
 }
 
+static inline int regulator_allow_bypass(struct regulator *regulator,
+					 bool allow)
+{
+	return 0;
+}
+
 static inline int regulator_register_notifier(struct regulator *regulator,
 			      struct notifier_block *nb)
 {
diff --git a/include/linux/regulator/driver.h b/include/linux/regulator/driver.h
index bac4c871f3b..c9869cfbf26 100644
--- a/include/linux/regulator/driver.h
+++ b/include/linux/regulator/driver.h
@@ -32,6 +32,8 @@ enum regulator_status {
 	REGULATOR_STATUS_NORMAL,
 	REGULATOR_STATUS_IDLE,
 	REGULATOR_STATUS_STANDBY,
+	/* The regulator is enabled but not regulating */
+	REGULATOR_STATUS_BYPASS,
 	/* in case that any other status doesn't apply */
 	REGULATOR_STATUS_UNDEFINED,
 };
@@ -67,6 +69,9 @@ enum regulator_status {
  * @get_optimum_mode: Get the most efficient operating mode for the regulator
  *                    when running with the specified parameters.
  *
+ * @set_bypass: Set the regulator in bypass mode.
+ * @get_bypass: Get the regulator bypass mode state.
+ *
  * @enable_time: Time taken for the regulator voltage output voltage to
  *               stabilise after being enabled, in microseconds.
  * @set_ramp_delay: Set the ramp delay for the regulator. The driver should
@@ -133,6 +138,10 @@ struct regulator_ops {
 	unsigned int (*get_optimum_mode) (struct regulator_dev *, int input_uV,
 					  int output_uV, int load_uA);
 
+	/* control and report on bypass mode */
+	int (*set_bypass)(struct regulator_dev *dev, bool enable);
+	int (*get_bypass)(struct regulator_dev *dev, bool *enable);
+
 	/* the operations below are for configuration of regulator state when
 	 * its parent PMIC enters a global STANDBY/HIBERNATE state */
 
@@ -253,6 +262,7 @@ struct regulator_dev {
 	int exclusive;
 	u32 use_count;
 	u32 open_count;
+	u32 bypass_count;
 
 	/* lists we belong to */
 	struct list_head list; /* list of all regulators */
diff --git a/include/linux/regulator/machine.h b/include/linux/regulator/machine.h
index 40dd0a394cf..36adbc82de6 100644
--- a/include/linux/regulator/machine.h
+++ b/include/linux/regulator/machine.h
@@ -32,6 +32,7 @@ struct regulator;
  *           board/machine.
  * STATUS:   Regulator can be enabled and disabled.
  * DRMS:     Dynamic Regulator Mode Switching is enabled for this regulator.
+ * BYPASS:   Regulator can be put into bypass mode
  */
 
 #define REGULATOR_CHANGE_VOLTAGE	0x1
@@ -39,6 +40,7 @@ struct regulator;
 #define REGULATOR_CHANGE_MODE		0x4
 #define REGULATOR_CHANGE_STATUS		0x8
 #define REGULATOR_CHANGE_DRMS		0x10
+#define REGULATOR_CHANGE_BYPASS		0x20
 
 /**
  * struct regulator_state - regulator state during low power system states