hwmon: (ina3221) Implement ti,single-shot DT property

By default, ina3221, as a hardware monitor, continuously measures
the inputs and generates corresponding data. However, for battery
powered devices, this mode might be power consuming.

The DT binding doc is updated with a new boolean type property to
allow changing the default operating mode from consuming mode to
single-shot mode, which will measure input on demand and then shut
down to save power.

So this patch implements the DT property accordingly.

Signed-off-by: Nicolin Chen <nicoleotsuka@gmail.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

1 files changed, 19 insertions, 0 deletions

diff --git a/drivers/hwmon/ina3221.c b/drivers/hwmon/ina3221.c
index f157214b3b83..3626b87a5fd2 100644
--- a/drivers/hwmon/ina3221.c
+++ b/drivers/hwmon/ina3221.c
@@ -111,6 +111,7 @@ struct ina3221_input {
  * @inputs: Array of channel input source specific structures
  * @lock: mutex lock to serialize sysfs attribute accesses
  * @reg_config: Register value of INA3221_CONFIG
+ * @single_shot: running in single-shot operating mode
  */
 struct ina3221_data {
         struct device *pm_dev;
@@ -119,6 +120,8 @@ struct ina3221_data {
         struct ina3221_input inputs[INA3221_NUM_CHANNELS];
         struct mutex lock;
         u32 reg_config;
+
+        bool single_shot;
 };
 
 static inline bool ina3221_is_enabled(struct ina3221_data *ina, int channel)
@@ -188,6 +191,11 @@ static int ina3221_read_in(struct device *dev, u32 attr, int channel, long *val)
                 if (!ina3221_is_enabled(ina, channel))
                         return -ENODATA;
 
+                /* Write CONFIG register to trigger a single-shot measurement */
+                if (ina->single_shot)
+                        regmap_write(ina->regmap, INA3221_CONFIG,
+                                     ina->reg_config);
+
                 ret = ina3221_wait_for_data(ina);
                 if (ret)
                         return ret;
@@ -232,6 +240,11 @@ static int ina3221_read_curr(struct device *dev, u32 attr,
                 if (!ina3221_is_enabled(ina, channel))
                         return -ENODATA;
 
+                /* Write CONFIG register to trigger a single-shot measurement */
+                if (ina->single_shot)
+                        regmap_write(ina->regmap, INA3221_CONFIG,
+                                     ina->reg_config);
+
                 ret = ina3221_wait_for_data(ina);
                 if (ret)
                         return ret;
@@ -614,6 +627,8 @@ static int ina3221_probe_from_dt(struct device *dev, struct ina3221_data *ina)
         if (!np)
                 return 0;
 
+        ina->single_shot = of_property_read_bool(np, "ti,single-shot");
+
         for_each_child_of_node(np, child) {
                 ret = ina3221_probe_child_from_dt(dev, child, ina);
                 if (ret)
@@ -663,6 +678,10 @@ static int ina3221_probe(struct i2c_client *client,
         /* The driver will be reset, so use reset value */
         ina->reg_config = INA3221_CONFIG_DEFAULT;
 
+        /* Clear continuous bit to use single-shot mode */
+        if (ina->single_shot)
+                ina->reg_config &= ~INA3221_CONFIG_MODE_CONTINUOUS;
+
         /* Disable channels if their inputs are disconnected */
         for (i = 0; i < INA3221_NUM_CHANNELS; i++) {
                 if (ina->inputs[i].disconnected)