[PATCH v6 0/4] hwmon: (pmbus/ltc2978) Add regulator ops

[PATCH v6 0/4] hwmon: (pmbus/ltc2978) Add regulator ops

[Mårten Lindahl]

Hi!

The LTC2978 driver supports a wide range of power regulator chips, but it
has limited functionality for using it in a dynamic regulator framework.
Since standard functions for setting and getting voltage are missing as
pmbus core operations this patchset adds it.

These patches have been tested on an ARTPEC-8 developer board with a group
of LTC2977 power regulators.

Kind regards
Mårten Lindahl

Changes in v2:
 - Add pmbus core _pmbus_write_byte_data to check for driver specific callback
 - Change pmbus_update_byte_data to use _pmbus_read/write_byte_data
 - Change pmbus_regulator_is_enabled to use _pmbus_read_byte_data
 - Export pmbus core functions enable/disable/is_enabled

Changes in v3:
 - Split patch "hwmon: (pmbus/ltc2978) Use driver specific ops if they exist"
   into two patches: (1) pmbus core, (2) ltc2978.
 - Move ltc2978_regulator_get/set_voltage functions to pmbus core.

Changes in v4:
 - Split (and rename) patch "hwmon: (pmbus) Use driver specific ops if they exist"
   into two patches where the first handle _pmbus_write_byte_data, and the
   second handle _pmbus_read_byte_data.
 - Use voltage conversion functions in pmbus_regulator_get/set_voltage.

Changes in v5:
 - Remove PMBUS_VOUT_COMMAND voltage attribute added in v4 and use local
   sensor object for conversion.
 - Try to read MFR_VOUT_MIN and MFR_VOUT_MAX first, or else VOUT_MARGIN_LOW and
   VOUT_MARGIN_HIGH, to get voltage window.

Changes in v6:
 - Don't use camelcase.
 - Keep convertion of uV to mV as integer.
 - Convert limits to voltages before testing requested value.

Mårten Lindahl (4):
  hwmon: (pmbus) Introduce and use write_byte_data callback
  hwmon: (pmbus) Use _pmbus_read_byte_data with callback
  hwmon: (pmbus/ltc2978) Add chip specific write_byte_data
  hwmon: (pmbus) Add get_voltage/set_voltage ops

 drivers/hwmon/pmbus/ltc2978.c    |  12 +++
 drivers/hwmon/pmbus/pmbus.h      |   2 +
 drivers/hwmon/pmbus/pmbus_core.c | 136 +++++++++++++++++++++++++------
 3 files changed, 124 insertions(+), 26 deletions(-)

-- 
2.30.2

[PATCH v6 1/4] hwmon: (pmbus) Introduce and use write_byte_data callback

[Mårten Lindahl]

Some of the pmbus core functions uses pmbus_write_byte_data, which does
not support driver callbacks for chip specific write operations. This
could potentially influence some specific regulator chips that for
example need a time delay before each data access.

Lets add support for driver callback with _pmbus_write_byte_data.

Signed-off-by: Mårten Lindahl <marten.lindahl@axis.com>
---
 drivers/hwmon/pmbus/pmbus.h      |  2 ++
 drivers/hwmon/pmbus/pmbus_core.c | 24 +++++++++++++++++++++---
 2 files changed, 23 insertions(+), 3 deletions(-)

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..98da2db3f831 100644
--- a/drivers/hwmon/pmbus/pmbus_core.c
+++ b/drivers/hwmon/pmbus/pmbus_core.c
@@ -276,6 +276,24 @@ static int _pmbus_write_word_data(struct i2c_client *client, int page, int reg,
 	return pmbus_write_word_data(client, page, reg, word);
 }
 
+/*
+ * _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_fan(struct i2c_client *client, int page, int id,
 		     u8 config, u8 mask, u16 command)
 {
@@ -290,7 +308,7 @@ int pmbus_update_fan(struct i2c_client *client, int page, int id,
 
 	to = (from & ~mask) | (config & mask);
 	if (to != from) {
-		rv = pmbus_write_byte_data(client, page,
+		rv = _pmbus_write_byte_data(client, page,
 					   pmbus_fan_config_registers[id], to);
 		if (rv < 0)
 			return rv;
@@ -397,7 +415,7 @@ int pmbus_update_byte_data(struct i2c_client *client, int page, u8 reg,
 	tmp = (rv & ~mask) | (value & mask);
 
 	if (tmp != rv)
-		rv = pmbus_write_byte_data(client, page, reg, tmp);
+		rv = _pmbus_write_byte_data(client, page, reg, tmp);
 
 	return rv;
 }
@@ -912,7 +930,7 @@ static int pmbus_get_boolean(struct i2c_client *client, struct pmbus_boolean *b,
 
 	regval = status & mask;
 	if (regval) {
-		ret = pmbus_write_byte_data(client, page, reg, regval);
+		ret = _pmbus_write_byte_data(client, page, reg, regval);
 		if (ret)
 			goto unlock;
 	}
-- 
2.30.2

[PATCH v6 2/4] hwmon: (pmbus) Use _pmbus_read_byte_data with callback

[Mårten Lindahl]

Some of the pmbus core functions uses pmbus_read_byte_data, which does
not support driver callbacks for chip specific write operations. This
could potentially influence some specific regulator chips that for
example need a time delay before each data access.

Lets use _pmbus_read_byte_data with callback check.

Signed-off-by: Mårten Lindahl <marten.lindahl@axis.com>
---
 drivers/hwmon/pmbus/pmbus_core.c | 46 ++++++++++++++++----------------
 1 file changed, 23 insertions(+), 23 deletions(-)

diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
index 98da2db3f831..bd143ca0c320 100644
--- a/drivers/hwmon/pmbus/pmbus_core.c
+++ b/drivers/hwmon/pmbus/pmbus_core.c
@@ -294,6 +294,24 @@ static int _pmbus_write_byte_data(struct i2c_client *client, int page, int reg,
 	return pmbus_write_byte_data(client, page, reg, value);
 }
 
+/*
+ * _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.
+ */
+static int _pmbus_read_byte_data(struct i2c_client *client, int page, int reg)
+{
+	struct pmbus_data *data = i2c_get_clientdata(client);
+	const struct pmbus_driver_info *info = data->info;
+	int status;
+
+	if (info->read_byte_data) {
+		status = info->read_byte_data(client, page, reg);
+		if (status != -ENODATA)
+			return status;
+	}
+	return pmbus_read_byte_data(client, page, reg);
+}
+
 int pmbus_update_fan(struct i2c_client *client, int page, int id,
 		     u8 config, u8 mask, u16 command)
 {
@@ -301,7 +319,7 @@ int pmbus_update_fan(struct i2c_client *client, int page, int id,
 	int rv;
 	u8 to;
 
-	from = pmbus_read_byte_data(client, page,
+	from = _pmbus_read_byte_data(client, page,
 				    pmbus_fan_config_registers[id]);
 	if (from < 0)
 		return from;
@@ -408,7 +426,7 @@ int pmbus_update_byte_data(struct i2c_client *client, int page, u8 reg,
 	unsigned int tmp;
 	int rv;
 
-	rv = pmbus_read_byte_data(client, page, reg);
+	rv = _pmbus_read_byte_data(client, page, reg);
 	if (rv < 0)
 		return rv;
 
@@ -421,24 +439,6 @@ int pmbus_update_byte_data(struct i2c_client *client, int page, u8 reg,
 }
 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.
- */
-static int _pmbus_read_byte_data(struct i2c_client *client, int page, int reg)
-{
-	struct pmbus_data *data = i2c_get_clientdata(client);
-	const struct pmbus_driver_info *info = data->info;
-	int status;
-
-	if (info->read_byte_data) {
-		status = info->read_byte_data(client, page, reg);
-		if (status != -ENODATA)
-			return status;
-	}
-	return pmbus_read_byte_data(client, page, reg);
-}
-
 static struct pmbus_sensor *pmbus_find_sensor(struct pmbus_data *data, int page,
 					      int reg)
 {
@@ -473,7 +473,7 @@ static int pmbus_get_fan_rate(struct i2c_client *client, int page, int id,
 		return s->data;
 	}
 
-	config = pmbus_read_byte_data(client, page,
+	config = _pmbus_read_byte_data(client, page,
 				      pmbus_fan_config_registers[id]);
 	if (config < 0)
 		return config;
@@ -2414,7 +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)
@@ -2513,7 +2513,7 @@ static int pmbus_regulator_get_error_flags(struct regulator_dev *rdev, unsigned
 		if (!(func & cat->func))
 			continue;
 
-		status = pmbus_read_byte_data(client, page, cat->reg);
+		status = _pmbus_read_byte_data(client, page, cat->reg);
 		if (status < 0) {
 			mutex_unlock(&data->update_lock);
 			return status;
-- 
2.30.2

[PATCH v6 3/4] hwmon: (pmbus/ltc2978) Add chip specific write_byte_data

[Mårten Lindahl]

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 we should add a driver specific callback
for write_byte_data to prevent bypassing the wait time recommendations
for the following devices: ltc3880/ltc3882/ltc3883/ltc3884/ltc3886/
ltc3887/ltc3889/ltm4664/ltm4675/ltm4676/ltm4677/ltm4678/ltm4680/ltm4686/
ltm4700/ltc7880.

Signed-off-by: Mårten Lindahl <marten.lindahl@axis.com>
---
 drivers/hwmon/pmbus/ltc2978.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

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;
 
-- 
2.30.2

[PATCH v6 4/4] hwmon: (pmbus) Add get_voltage/set_voltage ops

[Mårten Lindahl]

The pmbus core does not have operations for getting or setting voltage.
Add functions get/set voltage for the dynamic regulator framework.

Signed-off-by: Mårten Lindahl <marten.lindahl@axis.com>
---
 drivers/hwmon/pmbus/pmbus_core.c | 66 ++++++++++++++++++++++++++++++++
 1 file changed, 66 insertions(+)

diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
index bd143ca0c320..f2cf0439da37 100644
--- a/drivers/hwmon/pmbus/pmbus_core.c
+++ b/drivers/hwmon/pmbus/pmbus_core.c
@@ -2563,11 +2563,77 @@ static int pmbus_regulator_get_error_flags(struct regulator_dev *rdev, unsigned
 	return 0;
 }
 
+static int pmbus_regulator_get_voltage(struct regulator_dev *rdev)
+{
+	struct device *dev = rdev_get_dev(rdev);
+	struct i2c_client *client = to_i2c_client(dev->parent);
+	struct pmbus_data *data = i2c_get_clientdata(client);
+	struct pmbus_sensor s = {
+		.page = rdev_get_id(rdev),
+		.class = PSC_VOLTAGE_OUT,
+		.convert = true,
+	};
+
+	s.data = _pmbus_read_word_data(client, s.page, 0xff, PMBUS_READ_VOUT);
+	if (s.data < 0)
+		return s.data;
+
+	return (int)pmbus_reg2data(data, &s) * 1000; /* unit is uV */
+}
+
+static int pmbus_regulator_set_voltage(struct regulator_dev *rdev, int min_uv,
+					 int max_uv, unsigned int *selector)
+{
+	struct device *dev = rdev_get_dev(rdev);
+	struct i2c_client *client = to_i2c_client(dev->parent);
+	struct pmbus_data *data = i2c_get_clientdata(client);
+	struct pmbus_sensor s = {
+		.page = rdev_get_id(rdev),
+		.class = PSC_VOLTAGE_OUT,
+		.convert = true,
+		.data = -1,
+	};
+	int val = DIV_ROUND_CLOSEST(min_uv, 1000); /* convert to mV */
+	int low, high;
+	*selector = 0;
+
+	if (pmbus_check_word_register(client, s.page, PMBUS_MFR_VOUT_MIN))
+		s.data = _pmbus_read_word_data(client, s.page, 0xff, PMBUS_MFR_VOUT_MIN);
+	if (s.data < 0) {
+		s.data = _pmbus_read_word_data(client, s.page, 0xff, PMBUS_VOUT_MARGIN_LOW);
+		if (s.data < 0)
+			return s.data;
+	}
+	low = pmbus_reg2data(data, &s);
+	s.data = -1;
+
+	if (pmbus_check_word_register(client, s.page, PMBUS_MFR_VOUT_MAX))
+		s.data = _pmbus_read_word_data(client, s.page, 0xff, PMBUS_MFR_VOUT_MAX);
+	if (s.data < 0) {
+		s.data = _pmbus_read_word_data(client, s.page, 0xff, PMBUS_VOUT_MARGIN_HIGH);
+		if (s.data < 0)
+			return s.data;
+	}
+	high = pmbus_reg2data(data, &s);
+
+	/* Make sure we are within margins */
+	if (low > val)
+		val = low;
+	if (high < val)
+		val = high;
+
+	val = pmbus_data2reg(data, &s, val);
+
+	return _pmbus_write_word_data(client, s.page, PMBUS_VOUT_COMMAND, (u16)val);
+}
+
 const struct regulator_ops pmbus_regulator_ops = {
 	.enable = pmbus_regulator_enable,
 	.disable = pmbus_regulator_disable,
 	.is_enabled = pmbus_regulator_is_enabled,
 	.get_error_flags = pmbus_regulator_get_error_flags,
+	.get_voltage = pmbus_regulator_get_voltage,
+	.set_voltage = pmbus_regulator_set_voltage,
 };
 EXPORT_SYMBOL_NS_GPL(pmbus_regulator_ops, PMBUS);
 
-- 
2.30.2

Re: [PATCH v6 4/4] hwmon: (pmbus) Add get_voltage/set_voltage ops

[Guenter Roeck]

On Tue, May 03, 2022 at 12:46:31PM +0200, Mårten Lindahl wrote:
> The pmbus core does not have operations for getting or setting voltage.
> Add functions get/set voltage for the dynamic regulator framework.
> 
> Signed-off-by: Mårten Lindahl <marten.lindahl@axis.com>
> ---
>  drivers/hwmon/pmbus/pmbus_core.c | 66 ++++++++++++++++++++++++++++++++
>  1 file changed, 66 insertions(+)
> 
> diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
> index bd143ca0c320..f2cf0439da37 100644
> --- a/drivers/hwmon/pmbus/pmbus_core.c
> +++ b/drivers/hwmon/pmbus/pmbus_core.c
> @@ -2563,11 +2563,77 @@ static int pmbus_regulator_get_error_flags(struct regulator_dev *rdev, unsigned
>  	return 0;
>  }
>  
> +static int pmbus_regulator_get_voltage(struct regulator_dev *rdev)
> +{
> +	struct device *dev = rdev_get_dev(rdev);
> +	struct i2c_client *client = to_i2c_client(dev->parent);
> +	struct pmbus_data *data = i2c_get_clientdata(client);
> +	struct pmbus_sensor s = {
> +		.page = rdev_get_id(rdev),
> +		.class = PSC_VOLTAGE_OUT,
> +		.convert = true,
> +	};
> +
> +	s.data = _pmbus_read_word_data(client, s.page, 0xff, PMBUS_READ_VOUT);
> +	if (s.data < 0)
> +		return s.data;
> +
> +	return (int)pmbus_reg2data(data, &s) * 1000; /* unit is uV */
> +}
> +
> +static int pmbus_regulator_set_voltage(struct regulator_dev *rdev, int min_uv,
> +					 int max_uv, unsigned int *selector)

Multi-line alignment is off.

> +{
> +	struct device *dev = rdev_get_dev(rdev);
> +	struct i2c_client *client = to_i2c_client(dev->parent);
> +	struct pmbus_data *data = i2c_get_clientdata(client);
> +	struct pmbus_sensor s = {
> +		.page = rdev_get_id(rdev),
> +		.class = PSC_VOLTAGE_OUT,
> +		.convert = true,
> +		.data = -1,
> +	};
> +	int val = DIV_ROUND_CLOSEST(min_uv, 1000); /* convert to mV */
> +	int low, high;

There should be an empty line here. Interesting, checkpatch doesn't complain.
No need to resend, I'll apply and fix it up.

Thanks,
Guenter

> +	*selector = 0;
> +
> +	if (pmbus_check_word_register(client, s.page, PMBUS_MFR_VOUT_MIN))
> +		s.data = _pmbus_read_word_data(client, s.page, 0xff, PMBUS_MFR_VOUT_MIN);
> +	if (s.data < 0) {
> +		s.data = _pmbus_read_word_data(client, s.page, 0xff, PMBUS_VOUT_MARGIN_LOW);
> +		if (s.data < 0)
> +			return s.data;
> +	}
> +	low = pmbus_reg2data(data, &s);
> +	s.data = -1;
> +
> +	if (pmbus_check_word_register(client, s.page, PMBUS_MFR_VOUT_MAX))
> +		s.data = _pmbus_read_word_data(client, s.page, 0xff, PMBUS_MFR_VOUT_MAX);
> +	if (s.data < 0) {
> +		s.data = _pmbus_read_word_data(client, s.page, 0xff, PMBUS_VOUT_MARGIN_HIGH);
> +		if (s.data < 0)
> +			return s.data;
> +	}
> +	high = pmbus_reg2data(data, &s);
> +
> +	/* Make sure we are within margins */
> +	if (low > val)
> +		val = low;
> +	if (high < val)
> +		val = high;
> +
> +	val = pmbus_data2reg(data, &s, val);
> +
> +	return _pmbus_write_word_data(client, s.page, PMBUS_VOUT_COMMAND, (u16)val);
> +}
> +
>  const struct regulator_ops pmbus_regulator_ops = {
>  	.enable = pmbus_regulator_enable,
>  	.disable = pmbus_regulator_disable,
>  	.is_enabled = pmbus_regulator_is_enabled,
>  	.get_error_flags = pmbus_regulator_get_error_flags,
> +	.get_voltage = pmbus_regulator_get_voltage,
> +	.set_voltage = pmbus_regulator_set_voltage,
>  };
>  EXPORT_SYMBOL_NS_GPL(pmbus_regulator_ops, PMBUS);
>