[PATCH] ina3221: add support for summation channel control

[Ninad Malwade <nmalwade@nvidia.com>]

Add support to initialize summation channel control via kernel device
tree property "summation-bypass". The channel which has this property
is excluded from channel summation.

Signed-off-by: Ninad Malwade <nmalwade@nvidia.com>
---
 .../devicetree/bindings/hwmon/ina3221.txt          |  2 ++
 drivers/hwmon/ina3221.c                            | 14 ++++++++++++--
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/Documentation/devicetree/bindings/hwmon/ina3221.txt b/Documentation/devicetree/bindings/hwmon/ina3221.txt
index fa63b6171407..c6e8e6aafcce 100644
--- a/Documentation/devicetree/bindings/hwmon/ina3221.txt
+++ b/Documentation/devicetree/bindings/hwmon/ina3221.txt
@@ -29,6 +29,7 @@ Texas Instruments INA3221 Device Tree Bindings
   Optional properties:
   - label: Name of the input source
   - shunt-resistor-micro-ohms: Shunt resistor value in micro-Ohm
+  - summation-bypass: exclude from channel summation.
 
 Example:
 
@@ -41,6 +42,7 @@ ina3221@40 {
 	input@0 {
 		reg = <0x0>;
 		status = "disabled";
+		summation-bypass;
 	};
 	input@1 {
 		reg = <0x1>;
diff --git a/drivers/hwmon/ina3221.c b/drivers/hwmon/ina3221.c
index 2a57f4b60c29..ba0d6da06947 100644
--- a/drivers/hwmon/ina3221.c
+++ b/drivers/hwmon/ina3221.c
@@ -104,6 +104,7 @@ struct ina3221_input {
 	const char *label;
 	int shunt_resistor;
 	bool disconnected;
+	bool summation_bypass;
 };
 
 /**
@@ -125,6 +126,7 @@ struct ina3221_data {
 	struct mutex lock;
 	u32 reg_config;
 	int summation_shunt_resistor;
+	u32 summation_channel_control;
 
 	bool single_shot;
 };
@@ -154,7 +156,8 @@ static inline int ina3221_summation_shunt_resistor(struct ina3221_data *ina)
 	int i, shunt_resistor = 0;
 
 	for (i = 0; i < INA3221_NUM_CHANNELS; i++) {
-		if (input[i].disconnected || !input[i].shunt_resistor)
+		if (input[i].disconnected || !input[i].shunt_resistor ||
+		    input[i].summation_bypass)
 			continue;
 		if (!shunt_resistor) {
 			/* Found the reference shunt resistor value */
@@ -786,6 +789,9 @@ static int ina3221_probe_child_from_dt(struct device *dev,
 	/* Save the connected input label if available */
 	of_property_read_string(child, "label", &input->label);
 
+	/* summation channel control */
+	input->summation_bypass = of_property_read_bool(child, "summation-bypass");
+
 	/* Overwrite default shunt resistor value optionally */
 	if (!of_property_read_u32(child, "shunt-resistor-micro-ohms", &val)) {
 		if (val < 1 || val > INT_MAX) {
@@ -873,6 +879,10 @@ static int ina3221_probe(struct i2c_client *client)
 
 	/* Initialize summation_shunt_resistor for summation channel control */
 	ina->summation_shunt_resistor = ina3221_summation_shunt_resistor(ina);
+	for (i = 0; i < INA3221_NUM_CHANNELS; i++) {
+		if (!ina->inputs[i].summation_bypass)
+			ina->summation_channel_control |= (BIT(14 - i));
+	}
 
 	ina->pm_dev = dev;
 	mutex_init(&ina->lock);
@@ -984,7 +994,7 @@ static int ina3221_resume(struct device *dev)
 		 */
 		ret = regmap_update_bits(ina->regmap, INA3221_MASK_ENABLE,
 					 INA3221_MASK_ENABLE_SCC_MASK,
-					 INA3221_MASK_ENABLE_SCC_MASK);
+					 ina->summation_channel_control);
 		if (ret) {
 			dev_err(dev, "Unable to control summation channel\n");
 			return ret;
-- 
2.17.1