iio: humidity: hts221: add power management support

Add system sleep power management support to hts221 driver
Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@st.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/iio/humidity/hts221.h

@@ -57,12 +57,15 @@ struct hts221_hw {
 
 	struct hts221_sensor sensors[HTS221_SENSOR_MAX];
 
+	bool enabled;
 	u8 odr;
 
 	const struct hts221_transfer_function *tf;
 	struct hts221_transfer_buffer tb;
 };
 
+extern const struct dev_pm_ops hts221_pm_ops;
+
 int hts221_config_drdy(struct hts221_hw *hw, bool enable);
 int hts221_probe(struct iio_dev *iio_dev);
 int hts221_power_on(struct hts221_hw *hw);

drivers/iio/humidity/hts221_core.c

@@ -13,6 +13,7 @@
 #include <linux/device.h>
 #include <linux/iio/sysfs.h>
 #include <linux/delay.h>
+#include <linux/pm.h>
 #include <asm/unaligned.h>
 
 #include "hts221.h"
@@ -307,15 +308,30 @@ hts221_sysfs_temp_oversampling_avail(struct device *dev,
 
 int hts221_power_on(struct hts221_hw *hw)
 {
-	return hts221_update_odr(hw, hw->odr);
+	int err;
+
+	err = hts221_update_odr(hw, hw->odr);
+	if (err < 0)
+		return err;
+
+	hw->enabled = true;
+
+	return 0;
 }
 
 int hts221_power_off(struct hts221_hw *hw)
 {
-	u8 data[] = {0x00, 0x00};
+	__le16 data = 0;
+	int err;
 
-	return hw->tf->write(hw->dev, HTS221_REG_CNTRL1_ADDR, sizeof(data),
-			     data);
+	err = hw->tf->write(hw->dev, HTS221_REG_CNTRL1_ADDR, sizeof(data),
+			    (u8 *)&data);
+	if (err < 0)
+		return err;
+
+	hw->enabled = false;
+
+	return 0;
 }
 
 static int hts221_parse_temp_caldata(struct hts221_hw *hw)
@@ -682,6 +698,36 @@ int hts221_probe(struct iio_dev *iio_dev)
 }
 EXPORT_SYMBOL(hts221_probe);
 
+static int __maybe_unused hts221_suspend(struct device *dev)
+{
+	struct iio_dev *iio_dev = dev_get_drvdata(dev);
+	struct hts221_hw *hw = iio_priv(iio_dev);
+	__le16 data = 0;
+	int err;
+
+	err = hw->tf->write(hw->dev, HTS221_REG_CNTRL1_ADDR, sizeof(data),
+			    (u8 *)&data);
+
+	return err < 0 ? err : 0;
+}
+
+static int __maybe_unused hts221_resume(struct device *dev)
+{
+	struct iio_dev *iio_dev = dev_get_drvdata(dev);
+	struct hts221_hw *hw = iio_priv(iio_dev);
+	int err = 0;
+
+	if (hw->enabled)
+		err = hts221_update_odr(hw, hw->odr);
+
+	return err;
+}
+
+const struct dev_pm_ops hts221_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(hts221_suspend, hts221_resume)
+};
+EXPORT_SYMBOL(hts221_pm_ops);
+
 MODULE_AUTHOR("Lorenzo Bianconi <lorenzo.bianconi@st.com>");
 MODULE_DESCRIPTION("STMicroelectronics hts221 sensor driver");
 MODULE_LICENSE("GPL v2");

drivers/iio/humidity/hts221_i2c.c

@@ -105,6 +105,7 @@ MODULE_DEVICE_TABLE(i2c, hts221_i2c_id_table);
 static struct i2c_driver hts221_driver = {
 	.driver = {
 		.name = "hts221_i2c",
+		.pm = &hts221_pm_ops,
 		.of_match_table = of_match_ptr(hts221_i2c_of_match),
 		.acpi_match_table = ACPI_PTR(hts221_acpi_match),
 	},

drivers/iio/humidity/hts221_spi.c

@@ -113,6 +113,7 @@ MODULE_DEVICE_TABLE(spi, hts221_spi_id_table);
 static struct spi_driver hts221_driver = {
 	.driver = {
 		.name = "hts221_spi",
+		.pm = &hts221_pm_ops,
 		.of_match_table = of_match_ptr(hts221_spi_of_match),
 	},
 	.probe = hts221_spi_probe,