iio: imu: st_lsm6dsx: add system power management support

Add system sleep power management support to st_lsm6dsx driver.
In particular during suspend phase each sensor is disabled and
hw fifo is configured in bypass in order to avoid subsequent
I/O operations. The patch has been tested on HiKey board device

Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@st.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

diff --git a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx.h b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx.h
index 7778520..46352c7 100644 (file)
--- a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx.h
+++ b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx.h
@@ -135,6 +135,8 @@ struct st_lsm6dsx_hw {
 #endif /* CONFIG_SPI_MASTER */
 };
 
+extern const struct dev_pm_ops st_lsm6dsx_pm_ops;
+
 int st_lsm6dsx_probe(struct device *dev, int irq, int hw_id, const char *name,
                     const struct st_lsm6dsx_transfer_function *tf_ops);
 int st_lsm6dsx_sensor_enable(struct st_lsm6dsx_sensor *sensor);

diff --git a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c
index 462a27b..1b53848 100644 (file)
--- a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c
+++ b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c
@@ -36,6 +36,7 @@
 #include <linux/delay.h>
 #include <linux/iio/iio.h>
 #include <linux/iio/sysfs.h>
+#include <linux/pm.h>
 
 #include <linux/platform_data/st_sensors_pdata.h>
 
@@ -731,6 +732,59 @@ int st_lsm6dsx_probe(struct device *dev, int irq, int hw_id, const char *name,
 }
 EXPORT_SYMBOL(st_lsm6dsx_probe);
 
+#ifdef CONFIG_PM
+static int st_lsm6dsx_suspend(struct device *dev)
+{
+       struct st_lsm6dsx_hw *hw = dev_get_drvdata(dev);
+       struct st_lsm6dsx_sensor *sensor;
+       int i, err = 0;
+
+       for (i = 0; i < ST_LSM6DSX_ID_MAX; i++) {
+               sensor = iio_priv(hw->iio_devs[i]);
+               if (!(hw->enable_mask & BIT(sensor->id)))
+                       continue;
+
+               err = st_lsm6dsx_write_with_mask(hw,
+                               st_lsm6dsx_odr_table[sensor->id].reg.addr,
+                               st_lsm6dsx_odr_table[sensor->id].reg.mask, 0);
+               if (err < 0)
+                       return err;
+       }
+
+       if (hw->fifo_mode != ST_LSM6DSX_FIFO_BYPASS)
+               err = st_lsm6dsx_flush_fifo(hw);
+
+       return err;
+}
+
+static int st_lsm6dsx_resume(struct device *dev)
+{
+       struct st_lsm6dsx_hw *hw = dev_get_drvdata(dev);
+       struct st_lsm6dsx_sensor *sensor;
+       int i, err = 0;
+
+       for (i = 0; i < ST_LSM6DSX_ID_MAX; i++) {
+               sensor = iio_priv(hw->iio_devs[i]);
+               if (!(hw->enable_mask & BIT(sensor->id)))
+                       continue;
+
+               err = st_lsm6dsx_set_odr(sensor, sensor->odr);
+               if (err < 0)
+                       return err;
+       }
+
+       if (hw->enable_mask)
+               err = st_lsm6dsx_set_fifo_mode(hw, ST_LSM6DSX_FIFO_CONT);
+
+       return err;
+}
+#endif /* CONFIG_PM */
+
+const struct dev_pm_ops st_lsm6dsx_pm_ops = {
+       SET_SYSTEM_SLEEP_PM_OPS(st_lsm6dsx_suspend, st_lsm6dsx_resume)
+};
+EXPORT_SYMBOL(st_lsm6dsx_pm_ops);
+
 MODULE_AUTHOR("Lorenzo Bianconi <lorenzo.bianconi@st.com>");
 MODULE_AUTHOR("Denis Ciocca <denis.ciocca@st.com>");
 MODULE_DESCRIPTION("STMicroelectronics st_lsm6dsx driver");

diff --git a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_i2c.c b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_i2c.c
index 09a51cf..305fec7 100644 (file)
--- a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_i2c.c
+++ b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_i2c.c
@@ -98,6 +98,7 @@ MODULE_DEVICE_TABLE(i2c, st_lsm6dsx_i2c_id_table);
 static struct i2c_driver st_lsm6dsx_driver = {
        .driver = {
                .name = "st_lsm6dsx_i2c",
+               .pm = &st_lsm6dsx_pm_ops,
                .of_match_table = of_match_ptr(st_lsm6dsx_i2c_of_match),
        },
        .probe = st_lsm6dsx_i2c_probe,

diff --git a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_spi.c b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_spi.c
index f765a50..95472f1 100644 (file)
--- a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_spi.c
+++ b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_spi.c
@@ -115,6 +115,7 @@ MODULE_DEVICE_TABLE(spi, st_lsm6dsx_spi_id_table);
 static struct spi_driver st_lsm6dsx_driver = {
        .driver = {
                .name = "st_lsm6dsx_spi",
+               .pm = &st_lsm6dsx_pm_ops,
                .of_match_table = of_match_ptr(st_lsm6dsx_spi_of_match),
        },
        .probe = st_lsm6dsx_spi_probe,