[PATCH v2 15/15] staging: iio: isl29028: add runtime power management support

From: Brian Masney
Date: Tue Jan 17 2017 - 04:44:01 EST


This patch adds runtime power management support to the isl29028 driver.
It defaults to powering off the device after two seconds of inactivity.

isl29028_chip_init_and_power_on() currently only zeros the CONFIGURE
register on the chip, which will cause the chip to turn off. This patch
also renames that function to isl29028_clear_configure_reg() since it is
now used in several places.

Signed-off-by: Brian Masney <masneyb@xxxxxxxxxxxxx>
---
drivers/staging/iio/light/isl29028.c | 118 ++++++++++++++++++++++++++++++++---
1 file changed, 110 insertions(+), 8 deletions(-)

diff --git a/drivers/staging/iio/light/isl29028.c b/drivers/staging/iio/light/isl29028.c
index 598a5a5..a3264f7 100644
--- a/drivers/staging/iio/light/isl29028.c
+++ b/drivers/staging/iio/light/isl29028.c
@@ -26,6 +26,7 @@
#include <linux/regmap.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
+#include <linux/pm_runtime.h>

#define ISL29028_CONV_TIME_MS 100

@@ -60,6 +61,8 @@

#define ISL29028_NUM_REGS (ISL29028_REG_TEST2_MODE + 1)

+#define ISL29028_POWER_OFF_DELAY_MS 2000
+
enum isl29028_als_ir_mode {
ISL29028_MODE_NONE = 0,
ISL29028_MODE_ALS,
@@ -297,6 +300,23 @@ static int isl29028_ir_get(struct isl29028_chip *chip, int *ir_data)
return isl29028_read_als_ir(chip, ir_data);
}

+static int isl29028_set_pm_runtime_busy(struct isl29028_chip *chip, bool on)
+{
+ struct device *dev = regmap_get_device(chip->regmap);
+ int ret;
+
+ if (on) {
+ ret = pm_runtime_get_sync(dev);
+ if (ret < 0)
+ pm_runtime_put_noidle(dev);
+ } else {
+ pm_runtime_mark_last_busy(dev);
+ ret = pm_runtime_put_autosuspend(dev);
+ }
+
+ return ret;
+}
+
/* Channel IO */
static int isl29028_write_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
@@ -304,9 +324,15 @@ static int isl29028_write_raw(struct iio_dev *indio_dev,
{
struct isl29028_chip *chip = iio_priv(indio_dev);
struct device *dev = regmap_get_device(chip->regmap);
- int ret = -EINVAL;
+ int ret;
+
+ ret = isl29028_set_pm_runtime_busy(chip, true);
+ if (ret < 0)
+ return ret;

mutex_lock(&chip->lock);
+
+ ret = -EINVAL;
switch (chan->type) {
case IIO_PROXIMITY:
if (mask != IIO_CHAN_INFO_SAMP_FREQ) {
@@ -350,6 +376,13 @@ static int isl29028_write_raw(struct iio_dev *indio_dev,

mutex_unlock(&chip->lock);

+ if (ret < 0)
+ return ret;
+
+ ret = isl29028_set_pm_runtime_busy(chip, false);
+ if (ret < 0)
+ return ret;
+
return ret;
}

@@ -359,9 +392,15 @@ static int isl29028_read_raw(struct iio_dev *indio_dev,
{
struct isl29028_chip *chip = iio_priv(indio_dev);
struct device *dev = regmap_get_device(chip->regmap);
- int ret = -EINVAL;
+ int ret, pm_ret;
+
+ ret = isl29028_set_pm_runtime_busy(chip, true);
+ if (ret < 0)
+ return ret;

mutex_lock(&chip->lock);
+
+ ret = -EINVAL;
switch (mask) {
case IIO_CHAN_INFO_RAW:
case IIO_CHAN_INFO_PROCESSED:
@@ -405,6 +444,18 @@ static int isl29028_read_raw(struct iio_dev *indio_dev,

mutex_unlock(&chip->lock);

+ if (ret < 0)
+ return ret;
+
+ /**
+ * Preserve the ret variable if the call to
+ * isl29028_set_pm_runtime_busy() is successful so the reading
+ * (if applicable) is returned to user space.
+ */
+ pm_ret = isl29028_set_pm_runtime_busy(chip, false);
+ if (pm_ret < 0)
+ return pm_ret;
+
return ret;
}

@@ -445,17 +496,18 @@ static const struct iio_info isl29028_info = {
.write_raw = isl29028_write_raw,
};

-static int isl29028_chip_init_and_power_on(struct isl29028_chip *chip)
+static int isl29028_clear_configure_reg(struct isl29028_chip *chip)
{
struct device *dev = regmap_get_device(chip->regmap);
int ret;

ret = regmap_write(chip->regmap, ISL29028_REG_CONFIGURE, 0x0);
- if (ret < 0) {
+ if (ret < 0)
dev_err(dev, "%s(): Error %d clearing the CONFIGURE register\n",
__func__, ret);
- return ret;
- }
+
+ chip->als_ir_mode = ISL29028_MODE_NONE;
+ chip->enable_prox = false;

return ret;
}
@@ -509,7 +561,6 @@ static int isl29028_probe(struct i2c_client *client,
chip->enable_prox = false;
chip->prox_sampling = 20;
chip->lux_scale = 2000;
- chip->als_ir_mode = ISL29028_MODE_NONE;

ret = regmap_write(chip->regmap, ISL29028_REG_TEST1_MODE, 0x0);
if (ret < 0) {
@@ -527,7 +578,7 @@ static int isl29028_probe(struct i2c_client *client,
return ret;
}

- ret = isl29028_chip_init_and_power_on(chip);
+ ret = isl29028_clear_configure_reg(chip);
if (ret < 0)
return ret;

@@ -538,6 +589,11 @@ static int isl29028_probe(struct i2c_client *client,
indio_dev->dev.parent = &client->dev;
indio_dev->modes = INDIO_DIRECT_MODE;

+ pm_runtime_enable(&client->dev);
+ pm_runtime_set_autosuspend_delay(&client->dev,
+ ISL29028_POWER_OFF_DELAY_MS);
+ pm_runtime_use_autosuspend(&client->dev);
+
ret = devm_iio_device_register(indio_dev->dev.parent, indio_dev);
if (ret < 0) {
dev_err(&client->dev,
@@ -549,6 +605,50 @@ static int isl29028_probe(struct i2c_client *client,
return 0;
}

+static int isl29028_remove(struct i2c_client *client)
+{
+ struct iio_dev *indio_dev = i2c_get_clientdata(client);
+ struct isl29028_chip *chip = iio_priv(indio_dev);
+
+ iio_device_unregister(indio_dev);
+
+ pm_runtime_disable(&client->dev);
+ pm_runtime_set_suspended(&client->dev);
+ pm_runtime_put_noidle(&client->dev);
+
+ return isl29028_clear_configure_reg(chip);
+}
+
+static int __maybe_unused isl29028_suspend(struct device *dev)
+{
+ struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
+ struct isl29028_chip *chip = iio_priv(indio_dev);
+ int ret;
+
+ mutex_lock(&chip->lock);
+
+ ret = isl29028_clear_configure_reg(chip);
+
+ mutex_unlock(&chip->lock);
+
+ return ret;
+}
+
+static int __maybe_unused isl29028_resume(struct device *dev)
+{
+ /**
+ * The specific component (ALS/IR or proximity) will enable itself as
+ * needed the next time that the user requests a reading. This is done
+ * above in isl29028_set_als_ir_mode() and isl29028_enable_proximity().
+ */
+ return 0;
+}
+
+static const struct dev_pm_ops isl29028_pm_ops = {
+ SET_SYSTEM_SLEEP_PM_OPS(isl29028_suspend, isl29028_resume)
+ SET_RUNTIME_PM_OPS(isl29028_suspend, isl29028_resume, NULL)
+};
+
static const struct i2c_device_id isl29028_id[] = {
{"isl29028", 0},
{}
@@ -565,9 +665,11 @@ MODULE_DEVICE_TABLE(of, isl29028_of_match);
static struct i2c_driver isl29028_driver = {
.driver = {
.name = "isl29028",
+ .pm = &isl29028_pm_ops,
.of_match_table = isl29028_of_match,
},
.probe = isl29028_probe,
+ .remove = isl29028_remove,
.id_table = isl29028_id,
};

--
2.9.3