[PATCH 2/3] hwmon: (pmbus/core) add POWER_GOOD signal limits support

[Jerome Brunet <jbrunet@baylibre.com>]

Add support for POWER_GOOD_ON and POWER_GOOD_OFF standard PMBus commands.

For PMBus devices that offer a POWER_GOOD signal, these commands are used
for setting the output voltage at which a power good signal should be
asserted and negated.

Power Good signals are device and manufacturer specific. Many factors other
than output voltage may be used to determine whether or not the POWER_GOOD
signal is to be asserted. PMBus device users are instructed to consult the
device manufacturer’s product literature for the specifics of the device
they are using.

Note that depending on the choice of the device manufacturer that a device
may drive a POWER_GOOD signal high or low to indicate that the signal is
asserted.

Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
---
 drivers/hwmon/pmbus/pmbus.h      | 3 +++
 drivers/hwmon/pmbus/pmbus_core.c | 6 ++++++
 2 files changed, 9 insertions(+)

diff --git a/drivers/hwmon/pmbus/pmbus.h b/drivers/hwmon/pmbus/pmbus.h
index 5d5dc774187b..e322d2dd9fb7 100644
--- a/drivers/hwmon/pmbus/pmbus.h
+++ b/drivers/hwmon/pmbus/pmbus.h
@@ -78,6 +78,9 @@ enum pmbus_regs {
 	PMBUS_IIN_OC_FAULT_LIMIT	= 0x5B,
 	PMBUS_IIN_OC_WARN_LIMIT		= 0x5D,
 
+	PMBUS_POWER_GOOD_ON		= 0x5E,
+	PMBUS_POWER_GOOD_OFF		= 0x5F,
+
 	PMBUS_POUT_OP_FAULT_LIMIT	= 0x68,
 	PMBUS_POUT_OP_WARN_LIMIT	= 0x6A,
 	PMBUS_PIN_OP_WARN_LIMIT		= 0x6B,
diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
index 0ea6fe7eb17c..94ddf0166770 100644
--- a/drivers/hwmon/pmbus/pmbus_core.c
+++ b/drivers/hwmon/pmbus/pmbus_core.c
@@ -1768,6 +1768,12 @@ static const struct pmbus_limit_attr vout_limit_attrs[] = {
 		.attr = "crit",
 		.alarm = "crit_alarm",
 		.sbit = PB_VOLTAGE_OV_FAULT,
+	}, {
+		.reg = PMBUS_POWER_GOOD_ON,
+		.attr = "good_on",
+	}, {
+		.reg = PMBUS_POWER_GOOD_OFF,
+		.attr = "good_off",
 	}, {
 		.reg = PMBUS_VIRT_READ_VOUT_AVG,
 		.update = true,

-- 
2.45.2