regulator: Add a regnode_set_constraint function

This method check that boot_on or always_on is set to 1 and if it
is it will try to enable the regulator.
The binding docs aren't clear on what to do but Linux enable the regulator
if any of those properties is set so we want to do the same.
The function first check the status to see if the regulator is
already enabled it then get the voltage to check if it is in a acceptable
range and then enables it.
This will be either called from the regnode_init method (if it's needed by the platform)
or by a SYSINIT at SI_SUB_LAST

Reviewed by:	mmel
MFC after:	1 week
Differential Revision:	https://reviews.freebsd.org/D22106

2 files changed, 70 insertions, 0 deletions

diff --git a/sys/dev/extres/regulator/regulator.c b/sys/dev/extres/regulator/regulator.c
index 53fe55b2bd0e..82e8d066818a 100644
--- a/sys/dev/extres/regulator/regulator.c
+++ b/sys/dev/extres/regulator/regulator.c
@@ -72,6 +72,7 @@ static int regnode_method_status(struct regnode *regnode, int *status);
 static int regnode_method_set_voltage(struct regnode *regnode, int min_uvolt,
     int max_uvolt, int *udelay);
 static int regnode_method_get_voltage(struct regnode *regnode, int *uvolt);
+static void regulator_constraint(void *dummy);
 static void regulator_shutdown(void *dummy);
 
 /*
@@ -154,9 +155,27 @@ SX_SYSINIT(regulator_topology, &regnode_topo_lock, "Regulator topology lock");
 #define REGNODE_XLOCK(_sc)	sx_xlock(&((_sc)->lock))
 #define REGNODE_UNLOCK(_sc)	sx_unlock(&((_sc)->lock))
 
+SYSINIT(regulator_constraint, SI_SUB_LAST, SI_ORDER_ANY, regulator_constraint,
+    NULL);
 SYSINIT(regulator_shutdown, SI_SUB_LAST, SI_ORDER_ANY, regulator_shutdown,
     NULL);
 
+static void
+regulator_constraint(void *dummy)
+{
+	struct regnode *entry;
+	int rv;
+
+	REG_TOPO_SLOCK();
+	TAILQ_FOREACH(entry, &regnode_list, reglist_link) {
+		rv = regnode_set_constraint(entry);
+		if (rv != 0 && bootverbose)
+			printf("regulator: setting constraint on %s failed (%d)\n",
+			    entry->name, rv);
+	}
+	REG_TOPO_UNLOCK();
+}
+
 /*
  * Disable unused regulator
  * We run this function at SI_SUB_LAST which mean that every driver that needs
@@ -780,6 +799,56 @@ regnode_set_voltage_checked(struct regnode *regnode, struct regulator *reg,
 	return (rv);
 }
 
+int
+regnode_set_constraint(struct regnode *regnode)
+{
+	int status, rv, uvolt;
+
+	if (regnode->std_param.boot_on != true &&
+	    regnode->std_param.always_on != true)
+		return (0);
+
+	rv = regnode_status(regnode, &status);
+	if (rv != 0) {
+		if (bootverbose)
+			printf("Cannot get regulator status for %s\n",
+			    regnode_get_name(regnode));
+		return (rv);
+	}
+
+	if (status == REGULATOR_STATUS_ENABLED)
+		return (0);
+
+	rv = regnode_get_voltage(regnode, &uvolt);
+	if (rv != 0) {
+		if (bootverbose)
+			printf("Cannot get regulator voltage for %s\n",
+			    regnode_get_name(regnode));
+		return (rv);
+	}
+
+	if (uvolt < regnode->std_param.min_uvolt ||
+	  uvolt > regnode->std_param.max_uvolt) {
+		if (bootverbose)
+			printf("Regulator %s current voltage %d is not in the"
+			    " acceptable range : %d<->%d\n",
+			    regnode_get_name(regnode),
+			    uvolt, regnode->std_param.min_uvolt,
+			    regnode->std_param.max_uvolt);
+		return (ERANGE);
+	}
+
+	rv = regnode_enable(regnode);
+	if (rv != 0) {
+		if (bootverbose)
+			printf("Cannot enable regulator %s\n",
+			    regnode_get_name(regnode));
+		return (rv);
+	}
+
+	return (0);
+}
+
 #ifdef FDT
 phandle_t
 regnode_get_ofw_node(struct regnode *regnode)
diff --git a/sys/dev/extres/regulator/regulator.h b/sys/dev/extres/regulator/regulator.h
index 7ef6524df35a..b0bbb8a54b6e 100644
--- a/sys/dev/extres/regulator/regulator.h
+++ b/sys/dev/extres/regulator/regulator.h
@@ -116,6 +116,7 @@ int regnode_stop(struct regnode *regnode, int depth);
 int regnode_status(struct regnode *regnode, int *status);
 int regnode_get_voltage(struct regnode *regnode, int *uvolt);
 int regnode_set_voltage(struct regnode *regnode, int min_uvolt, int max_uvolt);
+int regnode_set_constraint(struct regnode *regnode);
 #ifdef FDT
 phandle_t regnode_get_ofw_node(struct regnode *regnode);
 #endif