[PATCH v2 1/2] hwmon: (pmbus/ltc2978) Use driver specific ops if they exist

["Mårten Lindahl" <marten.lindahl@axis.com>]

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.

Since this driver uses the default pmbus_regulator_ops for the enable/
disable/is_enabled functions and these functions do not check for driver
specific read/write ops, the wait time recommendations are bypassed for
several of the devices managed by this driver (ltc3880/ltc3882/ltc3883/
ltc3884/ltc3886/ltc3887/ltc3889/ltm4664/ltm4675/ltm4676/ltm4677/ltm4678/
ltm4680/ltm4686/ltm4700/ltc7880).

Lets add support for driver specific callbacks in pmbus core which takes
the wait time into consideration for the specified devices.

Signed-off-by: Mårten Lindahl <marten.lindahl@axis.com>
---
 drivers/hwmon/pmbus/ltc2978.c    | 12 +++++++
 drivers/hwmon/pmbus/pmbus.h      |  2 ++
 drivers/hwmon/pmbus/pmbus_core.c | 58 +++++++++++++++++++++-----------
 3 files changed, 52 insertions(+), 20 deletions(-)

diff --git a/drivers/hwmon/pmbus/ltc2978.c b/drivers/hwmon/pmbus/ltc2978.c
index 0127273883f0..531aa674a928 100644
--- a/drivers/hwmon/pmbus/ltc2978.c
+++ b/drivers/hwmon/pmbus/ltc2978.c
@@ -196,6 +196,17 @@ static int ltc_read_byte_data(struct i2c_client *client, int page, int reg)
 	return pmbus_read_byte_data(client, page, reg);
 }
 
+static int ltc_write_byte_data(struct i2c_client *client, int page, int reg, u8 value)
+{
+	int ret;
+
+	ret = ltc_wait_ready(client);
+	if (ret < 0)
+		return ret;
+
+	return pmbus_write_byte_data(client, page, reg, value);
+}
+
 static int ltc_write_byte(struct i2c_client *client, int page, u8 byte)
 {
 	int ret;
@@ -681,6 +692,7 @@ static int ltc2978_probe(struct i2c_client *client)
 	info = &data->info;
 	info->write_word_data = ltc2978_write_word_data;
 	info->write_byte = ltc_write_byte;
+	info->write_byte_data = ltc_write_byte_data;
 	info->read_word_data = ltc_read_word_data;
 	info->read_byte_data = ltc_read_byte_data;
 
diff --git a/drivers/hwmon/pmbus/pmbus.h b/drivers/hwmon/pmbus/pmbus.h
index e74b6ef070f3..c031a9700ace 100644
--- a/drivers/hwmon/pmbus/pmbus.h
+++ b/drivers/hwmon/pmbus/pmbus.h
@@ -438,6 +438,8 @@ struct pmbus_driver_info {
 	int (*read_byte_data)(struct i2c_client *client, int page, int reg);
 	int (*read_word_data)(struct i2c_client *client, int page, int phase,
 			      int reg);
+	int (*write_byte_data)(struct i2c_client *client, int page, int reg,
+			      u8 byte);
 	int (*write_word_data)(struct i2c_client *client, int page, int reg,
 			       u16 word);
 	int (*write_byte)(struct i2c_client *client, int page, u8 value);
diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
index b2618b1d529e..1b0728c3c7d8 100644
--- a/drivers/hwmon/pmbus/pmbus_core.c
+++ b/drivers/hwmon/pmbus/pmbus_core.c
@@ -384,25 +384,6 @@ int pmbus_write_byte_data(struct i2c_client *client, int page, u8 reg, u8 value)
 }
 EXPORT_SYMBOL_NS_GPL(pmbus_write_byte_data, PMBUS);
 
-int pmbus_update_byte_data(struct i2c_client *client, int page, u8 reg,
-			   u8 mask, u8 value)
-{
-	unsigned int tmp;
-	int rv;
-
-	rv = pmbus_read_byte_data(client, page, reg);
-	if (rv < 0)
-		return rv;
-
-	tmp = (rv & ~mask) | (value & mask);
-
-	if (tmp != rv)
-		rv = pmbus_write_byte_data(client, page, reg, tmp);
-
-	return rv;
-}
-EXPORT_SYMBOL_NS_GPL(pmbus_update_byte_data, PMBUS);
-
 /*
  * _pmbus_read_byte_data() is similar to pmbus_read_byte_data(), but checks if
  * a device specific mapping function exists and calls it if necessary.
@@ -421,6 +402,43 @@ static int _pmbus_read_byte_data(struct i2c_client *client, int page, int reg)
 	return pmbus_read_byte_data(client, page, reg);
 }
 
+/*
+ * _pmbus_write_byte_data() is similar to pmbus_write_byte_data(), but checks if
+ * a device specific mapping function exists and calls it if necessary.
+ */
+static int _pmbus_write_byte_data(struct i2c_client *client, int page, int reg, u8 value)
+{
+	struct pmbus_data *data = i2c_get_clientdata(client);
+	const struct pmbus_driver_info *info = data->info;
+	int status;
+
+	if (info->write_byte_data) {
+		status = info->write_byte_data(client, page, reg, value);
+		if (status != -ENODATA)
+			return status;
+	}
+	return pmbus_write_byte_data(client, page, reg, value);
+}
+
+int pmbus_update_byte_data(struct i2c_client *client, int page, u8 reg,
+			   u8 mask, u8 value)
+{
+	unsigned int tmp;
+	int rv;
+
+	rv = _pmbus_read_byte_data(client, page, reg);
+	if (rv < 0)
+		return rv;
+
+	tmp = (rv & ~mask) | (value & mask);
+
+	if (tmp != rv)
+		rv = _pmbus_write_byte_data(client, page, reg, tmp);
+
+	return rv;
+}
+EXPORT_SYMBOL_NS_GPL(pmbus_update_byte_data, PMBUS);
+
 static struct pmbus_sensor *pmbus_find_sensor(struct pmbus_data *data, int page,
 					      int reg)
 {
@@ -2396,7 +2414,7 @@ static int pmbus_regulator_is_enabled(struct regulator_dev *rdev)
 	int ret;
 
 	mutex_lock(&data->update_lock);
-	ret = pmbus_read_byte_data(client, page, PMBUS_OPERATION);
+	ret = _pmbus_read_byte_data(client, page, PMBUS_OPERATION);
 	mutex_unlock(&data->update_lock);
 
 	if (ret < 0)
-- 
2.30.2