regulator: Add system_load constraint

Some regulators have a fixed load that isn't captured by
consumers that the kernel knows about. Add a constraint to
support this.

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/regulator/regulator.txt

@@ -37,6 +37,8 @@ Optional properties:
 - regulator-initial-mode: initial operating mode. The set of possible operating
   modes depends on the capabilities of every hardware so each device binding
   documentation explains which values the regulator supports.
+- regulator-system-load: Load in uA present on regulator that is not captured by
+  any consumer request.
 
 Deprecated properties:
 - regulator-compatible: If a regulator chip contains multiple

drivers/regulator/core.c

@@ -678,6 +678,8 @@ static int drms_uA_update(struct regulator_dev *rdev)
 	list_for_each_entry(sibling, &rdev->consumer_list, list)
 		current_uA += sibling->uA_load;
 
+	current_uA += rdev->constraints->system_load;
+
 	if (rdev->desc->ops->set_load) {
 		/* set the optimum mode for our new total regulator load */
 		err = rdev->desc->ops->set_load(rdev, current_uA);

drivers/regulator/of_regulator.c

@@ -95,6 +95,9 @@ static void of_get_regulation_constraints(struct device_node *np,
 		}
 	}
 
+	if (!of_property_read_u32(np, "regulator-system-load", &pval))
+		constraints->system_load = pval;
+
 	for (i = 0; i < ARRAY_SIZE(regulator_states); i++) {
 		switch (i) {
 		case PM_SUSPEND_MEM:

include/linux/regulator/machine.h

@@ -75,6 +75,7 @@ struct regulator_state {
  *
  * @min_uA: Smallest current consumers may set.
  * @max_uA: Largest current consumers may set.
+ * @system_load: Load that isn't captured by any consumer requests.
  *
  * @valid_modes_mask: Mask of modes which may be configured by consumers.
  * @valid_ops_mask: Operations which may be performed by consumers.
@@ -112,6 +113,8 @@ struct regulation_constraints {
 	int min_uA;
 	int max_uA;
 
+	int system_load;
+
 	/* valid regulator operating modes for this machine */
 	unsigned int valid_modes_mask;