regulator: da9063: disable unused voltage monitors

Merge series from Benjamin Bara <bbara93@gmail.com>:

Follow-up for my initial patch regarding the disabling of unused
voltage monitors. We use the PWR_OK functionality, which asserts GP_FB2
if every monitored voltage is in range. This patch should provide the
possibility to deactivate a voltage monitor from the DT if the regulator
might be disabled during run time. For this purpose, the regulator
notification support is used:
https://lore.kernel.org/all/cover.1622628333.git.matti.vaittinen@fi.rohmeurope.com/

Documentation/devicetree/bindings/mfd/dlg,da9063.yaml

@@ -12,6 +12,11 @@ maintainers:
 description: |
   For device-tree bindings of other sub-modules refer to the binding documents
   under the respective sub-system directories.
+  Using regulator-{uv,ov}-{warn,error,protection}-microvolt requires special
+  handling: First, when GP_FB2 is used, it must be ensured that there is no
+  moment where all voltage monitors are disabled. Next, as da9063 only supports
+  UV *and* OV monitoring, both must be set to the same severity and value
+  (0: disable, 1: enable).
 
 properties:
   compatible:
@@ -121,11 +126,19 @@ examples:
             regulator-max-microamp = <2000000>;
             regulator-boot-on;
           };
+          ldo6 {
+            /* UNUSED */
+            regulator-name = "LDO_6";
+            regulator-uv-protection-microvolt = <0>;
+            regulator-ov-protection-microvolt = <0>;
+          };
           ldo11 {
             regulator-name = "LDO_11";
             regulator-min-microvolt = <900000>;
-            regulator-max-microvolt = <3600000>;
-            regulator-boot-on;
+            regulator-max-microvolt = <900000>;
+            regulator-uv-protection-microvolt = <1>;
+            regulator-ov-protection-microvolt = <1>;
+            regulator-always-on;
           };
         };
       };

include/linux/mfd/da9063/registers.h

@@ -1040,6 +1040,29 @@
 /* DA9063_REG_CONFIG_J (addr=0x10F) */
 #define DA9063_TWOWIRE_TO			0x40
 
+/* DA9063_REG_MON_REG_2 (addr=0x115) */
+#define DA9063_LDO1_MON_EN			0x01
+#define DA9063_LDO2_MON_EN			0x02
+#define DA9063_LDO3_MON_EN			0x04
+#define DA9063_LDO4_MON_EN			0x08
+#define DA9063_LDO5_MON_EN			0x10
+#define DA9063_LDO6_MON_EN			0x20
+#define DA9063_LDO7_MON_EN			0x40
+#define DA9063_LDO8_MON_EN			0x80
+
+/* DA9063_REG_MON_REG_3 (addr=0x116) */
+#define DA9063_LDO9_MON_EN			0x01
+#define DA9063_LDO10_MON_EN			0x02
+#define DA9063_LDO11_MON_EN			0x04
+
+/* DA9063_REG_MON_REG_4 (addr=0x117) */
+#define DA9063_BCORE1_MON_EN			0x04
+#define DA9063_BCORE2_MON_EN			0x08
+#define DA9063_BPRO_MON_EN			0x10
+#define DA9063_BIO_MON_EN			0x20
+#define DA9063_BMEM_MON_EN			0x40
+#define DA9063_BPERI_MON_EN			0x80
+
 /* DA9063_REG_MON_REG_5 (addr=0x116) */
 #define DA9063_MON_A8_IDX_MASK			0x07
 #define		DA9063_MON_A8_IDX_NONE		0x00