[PATCH 10/10 v3] iio: pressure: bmp280: add power management

[Linus Walleij <linus.walleij@linaro.org>]

The PM280 has an internal standby-mode, but to really save power
we should shut the sensor down and disconnect the power. With
the proper .pm hooks we can enable both runtime and system power
management of the sensor. We use the *force callbacks from the
system PM hooks. When the sensor comes back we always reconfigure
it to make sure it is ready to roll as expected.

Cc: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
ChangeLog v0->v3:
- New patch on top of the reworked patches: we can add runtime PM,
  so we should.
---
 drivers/iio/pressure/bmp280-core.c | 65 ++++++++++++++++++++++++++++++++++++++
 drivers/iio/pressure/bmp280-i2c.c  |  1 +
 drivers/iio/pressure/bmp280-spi.c  |  3 +-
 drivers/iio/pressure/bmp280.h      |  3 ++
 4 files changed, 71 insertions(+), 1 deletion(-)

diff --git a/drivers/iio/pressure/bmp280-core.c b/drivers/iio/pressure/bmp280-core.c
index f7233641c643..52ea8e465d7d 100644
--- a/drivers/iio/pressure/bmp280-core.c
+++ b/drivers/iio/pressure/bmp280-core.c
@@ -31,6 +31,7 @@
 #include <linux/irq.h> /* For irq_get_irq_data() */
 #include <linux/completion.h>
 #include <linux/random.h>
+#include <linux/pm_runtime.h>
 
 #include "bmp280.h"
 
@@ -358,6 +359,7 @@ static int bmp280_read_raw(struct iio_dev *indio_dev,
 	int ret;
 	struct bmp280_data *data = iio_priv(indio_dev);
 
+	pm_runtime_get_sync(data->dev);
 	mutex_lock(&data->lock);
 
 	switch (mask) {
@@ -402,6 +404,8 @@ static int bmp280_read_raw(struct iio_dev *indio_dev,
 	}
 
 	mutex_unlock(&data->lock);
+	pm_runtime_mark_last_busy(data->dev);
+	pm_runtime_put_autosuspend(data->dev);
 
 	return ret;
 }
@@ -466,6 +470,7 @@ static int bmp280_write_raw(struct iio_dev *indio_dev,
 
 	switch (mask) {
 	case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
+		pm_runtime_get_sync(data->dev);
 		mutex_lock(&data->lock);
 		switch (chan->type) {
 		case IIO_HUMIDITYRELATIVE:
@@ -482,6 +487,8 @@ static int bmp280_write_raw(struct iio_dev *indio_dev,
 			break;
 		}
 		mutex_unlock(&data->lock);
+		pm_runtime_mark_last_busy(data->dev);
+		pm_runtime_put_autosuspend(data->dev);
 		break;
 	default:
 		return -EINVAL;
@@ -1028,6 +1035,18 @@ int bmp280_common_probe(struct device *dev,
 		dev_err(dev, "unable to register IIO device\n");
 		goto out_disable_vdda;
 	}
+
+	/* Enable runtime PM */
+	pm_runtime_get_noresume(dev);
+	pm_runtime_set_active(dev);
+	pm_runtime_enable(dev);
+	/*
+	 * Set autosuspend to two orders of magnitude larger than the
+	 * start-up time.
+	 */
+	pm_runtime_set_autosuspend_delay(dev, data->start_up_time *100);
+	pm_runtime_use_autosuspend(dev);
+	pm_runtime_put(dev);
 	return 0;
 
 out_disable_vdda:
@@ -1042,8 +1061,54 @@ int bmp280_common_remove(struct device *dev)
 {
 	struct bmp280_data *data = dev_get_drvdata(dev);
 
+	pm_runtime_get_sync(data->dev);
+	pm_runtime_put_noidle(data->dev);
+	pm_runtime_disable(data->dev);
 	regulator_disable(data->vdda);
 	regulator_disable(data->vddd);
 	return 0;
 }
 EXPORT_SYMBOL(bmp280_common_remove);
+
+#ifdef CONFIG_PM
+static int bmp280_runtime_suspend(struct device *dev)
+{
+	struct bmp280_data *data = dev_get_drvdata(dev);
+	int ret;
+
+	ret = regulator_disable(data->vdda);
+	if (ret)
+		return ret;
+	ret = regulator_disable(data->vddd);
+	if (ret)
+		return ret;
+	return 0;
+}
+
+static int bmp280_runtime_resume(struct device *dev)
+{
+	struct bmp280_data *data = dev_get_drvdata(dev);
+	int ret;
+
+	ret = regulator_enable(data->vddd);
+	if (ret)
+		return ret;
+	ret = regulator_enable(data->vdda);
+	if (ret)
+		return ret;
+	msleep(data->start_up_time);
+	ret = data->chip_info->chip_config(data);
+	if (ret)
+		return ret;
+	return 0;
+
+}
+#endif /* CONFIG_PM */
+
+const struct dev_pm_ops bmp280_dev_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
+				pm_runtime_force_resume)
+	SET_RUNTIME_PM_OPS(bmp280_runtime_suspend,
+			   bmp280_runtime_resume, NULL)
+};
+EXPORT_SYMBOL(bmp280_dev_pm_ops);
diff --git a/drivers/iio/pressure/bmp280-i2c.c b/drivers/iio/pressure/bmp280-i2c.c
index 8cf8a900bdaa..03742b15b72a 100644
--- a/drivers/iio/pressure/bmp280-i2c.c
+++ b/drivers/iio/pressure/bmp280-i2c.c
@@ -78,6 +78,7 @@ static struct i2c_driver bmp280_i2c_driver = {
 		.name	= "bmp280",
 		.acpi_match_table = ACPI_PTR(bmp280_acpi_i2c_match),
 		.of_match_table = of_match_ptr(bmp280_of_i2c_match),
+		.pm = &bmp280_dev_pm_ops,
 	},
 	.probe		= bmp280_i2c_probe,
 	.remove		= bmp280_i2c_remove,
diff --git a/drivers/iio/pressure/bmp280-spi.c b/drivers/iio/pressure/bmp280-spi.c
index 2468224edb79..99b7386dffb3 100644
--- a/drivers/iio/pressure/bmp280-spi.c
+++ b/drivers/iio/pressure/bmp280-spi.c
@@ -112,7 +112,8 @@ MODULE_DEVICE_TABLE(spi, bmp280_spi_id);
 static struct spi_driver bmp280_spi_driver = {
 	.driver = {
 		.name = "bmp280",
-		.of_match_table = bmp280_of_spi_match
+		.of_match_table = bmp280_of_spi_match,
+		.pm = &bmp280_dev_pm_ops,
 	},
 	.id_table = bmp280_spi_id,
 	.probe = bmp280_spi_probe,
diff --git a/drivers/iio/pressure/bmp280.h b/drivers/iio/pressure/bmp280.h
index 573334b8e93b..3ba79d18639c 100644
--- a/drivers/iio/pressure/bmp280.h
+++ b/drivers/iio/pressure/bmp280.h
@@ -107,3 +107,6 @@ int bmp280_common_probe(struct device *dev,
 			const char *name,
 			int irq);
 int bmp280_common_remove(struct device *dev);
+
+/* Runtime PM ops */
+extern const struct dev_pm_ops bmp280_dev_pm_ops;
-- 
2.4.11