Add suspend and resume functions

The MSB (15th bit) of INA3221_CONFIG is a self-clear reset bit. So this register should be added to the volatile_table of the regmap_config. Otherwise, we will see this bit is sticky in the regcache which might accidentally reset the chip when an actual write happens to the register.

This might not be a severe bug for the current code line since there's no second place touching the INA3221_CONFIG except the reset routine in the probe().

Signed-off-by Nicolin Chen <[email protected]>

---
 drivers/hwmon/ina3221.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

drivers/hwmon/ina3221.c +1 -1

index e6b49500c52a..cfe65ff01051 100644
@@ -353,7 +353,7 @@ static struct attribute *ina3221_attrs[] = {
 ATTRIBUTE_GROUPS(ina3221);
 
 static const struct regmap_range ina3221_yes_ranges[] = {
-	regmap_reg_range(INA3221_SHUNT1, INA3221_BUS3),
+	regmap_reg_range(INA3221_CONFIG, INA3221_BUS3),
 	regmap_reg_range(INA3221_MASK_ENABLE, INA3221_MASK_ENABLE),
 };
 

The three INA3221_CONFIG_MODE macros are not correctly defined here. The MODE3-1 filed is loacted at BIT 2-0 according to the datasheet.

So this patch just fixes them by shifting all of them with a correct offset. However, this isn't a crital bug fix as the driver does not use any of them at this point.

Signed-off-by Nicolin Chen <[email protected]>

---
 drivers/hwmon/ina3221.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

drivers/hwmon/ina3221.c +3 -3

index cfe65ff01051..e0c4f4d83f4e 100644
@@ -38,9 +38,9 @@
 #define INA3221_WARN3			0x0c
 #define INA3221_MASK_ENABLE		0x0f
 
-#define INA3221_CONFIG_MODE_SHUNT	BIT(1)
-#define INA3221_CONFIG_MODE_BUS		BIT(2)
-#define INA3221_CONFIG_MODE_CONTINUOUS	BIT(3)
+#define INA3221_CONFIG_MODE_SHUNT	BIT(0)
+#define INA3221_CONFIG_MODE_BUS		BIT(1)
+#define INA3221_CONFIG_MODE_CONTINUOUS	BIT(2)
 
 #define INA3221_RSHUNT_DEFAULT		10000
 

Depending on the hardware design, an INA3221 chip might lose its power during system suspend/resume. So this patch adds a set of suspend and resume functions to cache the register values including config register value and limit settings.

Signed-off-by Nicolin Chen <[email protected]>

---
Changelog
v1->v2:
* Added power-down setting during suspend for power saving

 drivers/hwmon/ina3221.c | 63 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 63 insertions(+)

drivers/hwmon/ina3221.c +4 -0

index e0c4f4d83f4e..877952efaa88 100644
@@ -38,6 +38,8 @@
 #define INA3221_WARN3			0x0c
 #define INA3221_MASK_ENABLE		0x0f
 
+#define INA3221_CONFIG_MODE_MASK	GENMASK(2, 0)
+#define INA3221_CONFIG_MODE_POWERDOWN	0
 #define INA3221_CONFIG_MODE_SHUNT	BIT(0)
 #define INA3221_CONFIG_MODE_BUS		BIT(1)
 #define INA3221_CONFIG_MODE_CONTINUOUS	BIT(2)

@@ -91,11 +93,13 @@ static const unsigned int register_channel[] = {
  * @regmap: Register map of the device
  * @fields: Register fields of the device
  * @shunt_resistors: Array of resistor values per channel
+ * @reg_config: Register value of INA3221_CONFIG
  */
 struct ina3221_data {
 	struct regmap *regmap;
 	struct regmap_field *fields[F_MAX_FIELDS];
 	int shunt_resistors[INA3221_NUM_CHANNELS];
+	u32 reg_config;
 };
 
 static int ina3221_read_value(struct ina3221_data *ina, unsigned int reg,

drivers/hwmon/ina3221.c +57 -0

 	return 0;
 }
 
+#ifdef CONFIG_PM
+static int ina3221_suspend(struct device *dev)
+{
+	struct ina3221_data *ina = dev_get_drvdata(dev);
+	int ret;
+
+	/* Save config register value and enable cache-only */
+	ret = regmap_read(ina->regmap, INA3221_CONFIG, &ina->reg_config);
+	if (ret)
+		return ret;
+
+	/* Set to power-down mode for power saving */
+	ret = regmap_update_bits(ina->regmap, INA3221_CONFIG,
+				 INA3221_CONFIG_MODE_MASK,
+				 INA3221_CONFIG_MODE_POWERDOWN);
+	if (ret)
+		return ret;
+
+	regcache_cache_only(ina->regmap, true);
+	regcache_mark_dirty(ina->regmap);
+
+	return 0;
+}
+
+static int ina3221_resume(struct device *dev)
+{
+	struct ina3221_data *ina = dev_get_drvdata(dev);
+	int ret;
+
+	regcache_cache_only(ina->regmap, false);
+
+	/* Software reset the chip */
+	ret = regmap_field_write(ina->fields[F_RST], true);
+	if (ret) {
+		dev_err(dev, "Unable to reset device\n");
+		return ret;
+	}
+
+	/* Restore cached register values to hardware */
+	ret = regcache_sync(ina->regmap);
+	if (ret)
+		return ret;
+
+	/* Restore config register value to hardware */
+	ret = regmap_write(ina->regmap, INA3221_CONFIG, ina->reg_config);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+#endif
+
+static const struct dev_pm_ops ina3221_pm = {
+	SET_SYSTEM_SLEEP_PM_OPS(ina3221_suspend, ina3221_resume)
+};
+
 static const struct of_device_id ina3221_of_match_table[] = {
 	{ .compatible = "ti,ina3221", },
 	{ /* sentinel */ }

@@ -435,6 +497,7 @@ static struct i2c_driver ina3221_i2c_driver = {
 	.driver = {
 		.name = INA3221_DRIVER_NAME,
 		.of_match_table = ina3221_of_match_table,
+		.pm = &ina3221_pm,
 	},
 	.id_table = ina3221_ids,
 };

drivers/hwmon/ina3221.c static int ina3221_probe(struct i2c_client *client, · line 423

Quoted 7 lines

static int ina3221_read_value(struct ina3221_data *ina, unsigned int reg,

drivers/hwmon/ina3221.c +2 -0

@@ -415,9 +419,67 @@ static int ina3221_probe(struct i2c_client *client,
 		return PTR_ERR(hwmon_dev);
 	}
 
+	dev_set_drvdata(dev, ina);
+

It is better to call that function before registering the hwmon device, to avoid the theroretical possibility that suspend is called before drvdata is set. I moved the call accordingly.