[PATCH 1/2] hwmon: (pmbus/ltc2978) Add driver specific regulator ops

[Mårten Lindahl <marten.lindahl@xxxxxxxx>]

Several of the manuals for devices supported by this driver describes
the need for a minimum wait time before the chip is ready to receive
next command.

This wait time is already implemented in the driver as a ltc_wait_ready
function with a driver defined wait time of 100 ms, and is considered
for specific devices before reading/writing data on the pmbus.

But this driver uses the default pmbus_regulator_ops for the enable/
disable/is_enabled functions. By using these functions it bypasses the
wait time recommendations for several of the devices managed by the
driver (ltc3880/ltc3882/ltc3883/ltc3884/ltc3886/ltc3887/ltc3889/ltm4664/
ltm4675/ltm4676/ltm4677/ltm4678/ltm4680/ltm4686/ltm4700/ltc7880).

Lets add driver specific regulator enable/disable/is_enabled ops which
takes the wait time into consideration for the specified devices, by
overriding pmbus_read_byte_data with internal ltc_read_byte_data.

Signed-off-by: Mårten Lindahl <marten.lindahl@xxxxxxxx>
---
 drivers/hwmon/pmbus/ltc2978.c | 79 +++++++++++++++++++++++++++++++----
 1 file changed, 71 insertions(+), 8 deletions(-)

diff --git a/drivers/hwmon/pmbus/ltc2978.c b/drivers/hwmon/pmbus/ltc2978.c
index 0127273883f0..822edec33ba7 100644
--- a/drivers/hwmon/pmbus/ltc2978.c
+++ b/drivers/hwmon/pmbus/ltc2978.c
@@ -551,15 +551,78 @@ static const struct i2c_device_id ltc2978_id[] = {
 MODULE_DEVICE_TABLE(i2c, ltc2978_id);
 
 #if IS_ENABLED(CONFIG_SENSORS_LTC2978_REGULATOR)
+static int ltc2978_regulator_is_enabled(struct regulator_dev *rdev)
+{
+	struct device *dev = rdev_get_dev(rdev);
+	struct i2c_client *client = to_i2c_client(dev->parent);
+	u8 page = rdev_get_id(rdev);
+	int ret;
+
+	ret = ltc_read_byte_data(client, page, PMBUS_OPERATION);
+	if (ret < 0)
+		return ret;
+
+	return !!(ret & PB_OPERATION_CONTROL_ON);
+}
+
+static int ltc2978_regulator_on_off(struct regulator_dev *rdev, bool enable)
+{
+	struct device *dev = rdev_get_dev(rdev);
+	struct i2c_client *client = to_i2c_client(dev->parent);
+	u8 page = rdev_get_id(rdev);
+	unsigned int tmp;
+	int rv;
+
+	rv = ltc_read_byte_data(client, page, PMBUS_OPERATION);
+	if (rv < 0)
+		return rv;
+
+	tmp = (rv & ~PB_OPERATION_CONTROL_ON) |
+	    (enable ? PB_OPERATION_CONTROL_ON : 0);
+
+	if (tmp != rv)
+		rv = pmbus_write_byte_data(client, page, PMBUS_OPERATION, tmp);
+
+	return rv;
+}
+
+static int ltc2978_regulator_enable(struct regulator_dev *rdev)
+{
+	return ltc2978_regulator_on_off(rdev, 1);
+}
+
+static int ltc2978_regulator_disable(struct regulator_dev *rdev)
+{
+	return ltc2978_regulator_on_off(rdev, 0);
+}
+
+static const struct regulator_ops ltc2978_regulator_ops = {
+	.enable = ltc2978_regulator_enable,
+	.disable = ltc2978_regulator_disable,
+	.is_enabled = ltc2978_regulator_is_enabled,
+};
+
+/* Macro for filling in array of struct regulator_desc */
+#define PMBUS_LTC2978_REGULATOR(_name, _id)			\
+	[_id] = {						\
+		.name = (_name # _id),				\
+		.id = (_id),					\
+		.of_match = of_match_ptr(_name # _id),		\
+		.regulators_node = of_match_ptr("regulators"),	\
+		.ops = &ltc2978_regulator_ops,			\
+		.type = REGULATOR_VOLTAGE,			\
+		.owner = THIS_MODULE,				\
+	}
+
 static const struct regulator_desc ltc2978_reg_desc[] = {
-	PMBUS_REGULATOR("vout", 0),
-	PMBUS_REGULATOR("vout", 1),
-	PMBUS_REGULATOR("vout", 2),
-	PMBUS_REGULATOR("vout", 3),
-	PMBUS_REGULATOR("vout", 4),
-	PMBUS_REGULATOR("vout", 5),
-	PMBUS_REGULATOR("vout", 6),
-	PMBUS_REGULATOR("vout", 7),
+	PMBUS_LTC2978_REGULATOR("vout", 0),
+	PMBUS_LTC2978_REGULATOR("vout", 1),
+	PMBUS_LTC2978_REGULATOR("vout", 2),
+	PMBUS_LTC2978_REGULATOR("vout", 3),
+	PMBUS_LTC2978_REGULATOR("vout", 4),
+	PMBUS_LTC2978_REGULATOR("vout", 5),
+	PMBUS_LTC2978_REGULATOR("vout", 6),
+	PMBUS_LTC2978_REGULATOR("vout", 7),
 };
 #endif /* CONFIG_SENSORS_LTC2978_REGULATOR */
 
-- 
2.30.2