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iio: accel: mma9551: Add runtime pm support
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Add support for runtime pm to reduce the power consumed by the device
when not used.

If CONFIG_PM is not enabled, the device will be powered on at
init and only powered off on system suspend.

If CONFIG_PM is enabled, runtime pm autosuspend is used:
- for raw reads will keep the device on for a specified time
- for events it will keep the device on as long as we have at least
one event active

Signed-off-by: Irina Tirdea <irina.tirdea@intel.com>
Reviewed-by: Vlad Dogaru <vlad.dogaru@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
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Irina Tirdea authored and Jonathan Cameron committed Jan 27, 2015
1 parent 17a2cbc commit 6da93a6
Showing 1 changed file with 139 additions and 23 deletions.
162 changes: 139 additions & 23 deletions drivers/iio/accel/mma9551.c
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Original file line number Diff line number Diff line change
Expand Up @@ -22,6 +22,7 @@
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/events.h>
#include <linux/pm_runtime.h>

#define MMA9551_DRV_NAME "mma9551"
#define MMA9551_IRQ_NAME "mma9551_event"
Expand Down Expand Up @@ -71,6 +72,7 @@ enum mma9551_gpio_pin {
/* Sleep/Wake application */
#define MMA9551_SLEEP_CFG 0x06
#define MMA9551_SLEEP_CFG_SNCEN BIT(0)
#define MMA9551_SLEEP_CFG_FLEEN BIT(1)
#define MMA9551_SLEEP_CFG_SCHEN BIT(2)

/* AFE application */
Expand Down Expand Up @@ -114,6 +116,9 @@ enum mma9551_tilt_axis {
#define MMA9551_I2C_READ_RETRIES 5
#define MMA9551_I2C_READ_DELAY 50 /* us */

#define MMA9551_DEFAULT_SAMPLE_RATE 122 /* Hz */
#define MMA9551_AUTO_SUSPEND_DELAY_MS 2000

struct mma9551_mbox_request {
u8 start_mbox; /* Always 0. */
u8 app_id;
Expand Down Expand Up @@ -387,16 +392,55 @@ static int mma9551_read_version(struct i2c_client *client)
}

/*
* Power on chip and enable doze mode.
* Use 'false' as the second parameter to cause the device to enter
* sleep.
*/
static int mma9551_set_device_state(struct i2c_client *client,
bool enable)
static int mma9551_set_device_state(struct i2c_client *client, bool enable)
{
return mma9551_update_config_bits(client, MMA9551_APPID_SLEEP_WAKE,
MMA9551_SLEEP_CFG,
MMA9551_SLEEP_CFG_SNCEN,
enable ? 0 : MMA9551_SLEEP_CFG_SNCEN);
MMA9551_SLEEP_CFG_SNCEN |
MMA9551_SLEEP_CFG_FLEEN |
MMA9551_SLEEP_CFG_SCHEN,
enable ? MMA9551_SLEEP_CFG_SCHEN |
MMA9551_SLEEP_CFG_FLEEN :
MMA9551_SLEEP_CFG_SNCEN);
}

static int mma9551_set_power_state(struct i2c_client *client, bool on)
{
#ifdef CONFIG_PM
int ret;

if (on)
ret = pm_runtime_get_sync(&client->dev);
else {
pm_runtime_mark_last_busy(&client->dev);
ret = pm_runtime_put_autosuspend(&client->dev);
}

if (ret < 0) {
dev_err(&client->dev,
"failed to change power state to %d\n", on);
if (on)
pm_runtime_put_noidle(&client->dev);

return ret;
}
#endif

return 0;
}

static void mma9551_sleep(int freq)
{
int sleep_val = 1000 / freq;

if (sleep_val < 20)
usleep_range(sleep_val * 1000, 20000);
else
msleep_interruptible(sleep_val);
}

static int mma9551_read_incli_chan(struct i2c_client *client,
Expand Down Expand Up @@ -424,15 +468,19 @@ static int mma9551_read_incli_chan(struct i2c_client *client,
return -EINVAL;
}

ret = mma9551_set_power_state(client, true);
if (ret < 0)
return ret;

ret = mma9551_read_status_byte(client, MMA9551_APPID_TILT,
reg_addr, &angle);
if (ret < 0)
return ret;
goto out_poweroff;

ret = mma9551_read_status_byte(client, MMA9551_APPID_TILT,
MMA9551_TILT_QUAD_REG, &quadrant);
if (ret < 0)
return ret;
goto out_poweroff;

angle &= ~MMA9551_TILT_ANGFLG;
quadrant = (quadrant >> quad_shift) & 0x03;
Expand All @@ -442,7 +490,11 @@ static int mma9551_read_incli_chan(struct i2c_client *client,
else
*val = angle + 90 * quadrant;

return IIO_VAL_INT;
ret = IIO_VAL_INT;

out_poweroff:
mma9551_set_power_state(client, false);
return ret;
}

static int mma9551_read_accel_chan(struct i2c_client *client,
Expand All @@ -467,14 +519,22 @@ static int mma9551_read_accel_chan(struct i2c_client *client,
return -EINVAL;
}

ret = mma9551_set_power_state(client, true);
if (ret < 0)
return ret;

ret = mma9551_read_status_word(client, MMA9551_APPID_AFE,
reg_addr, &raw_accel);
if (ret < 0)
return ret;
goto out_poweroff;

*val = raw_accel;

return IIO_VAL_INT;
ret = IIO_VAL_INT;

out_poweroff:
mma9551_set_power_state(client, false);
return ret;
}

static int mma9551_read_raw(struct iio_dev *indio_dev,
Expand Down Expand Up @@ -556,6 +616,10 @@ static int mma9551_config_incli_event(struct iio_dev *indio_dev,
MMA9551_APPID_NONE, 0, 0);
if (ret < 0)
return ret;

ret = mma9551_set_power_state(data->client, false);
if (ret < 0)
return ret;
} else {
int bitnum;

Expand All @@ -574,11 +638,18 @@ static int mma9551_config_incli_event(struct iio_dev *indio_dev,
return -EINVAL;
}


ret = mma9551_set_power_state(data->client, true);
if (ret < 0)
return ret;

ret = mma9551_gpio_config(data->client,
(enum mma9551_gpio_pin)mma_axis,
MMA9551_APPID_TILT, bitnum, 0);
if (ret < 0)
if (ret < 0) {
mma9551_set_power_state(data->client, false);
return ret;
}
}

data->event_enabled[mma_axis] = state;
Expand Down Expand Up @@ -771,12 +842,7 @@ static int mma9551_init(struct mma9551_data *data)
if (ret)
return ret;

/* Power on chip and enable doze mode. */
return mma9551_update_config_bits(data->client,
MMA9551_APPID_SLEEP_WAKE,
MMA9551_SLEEP_CFG,
MMA9551_SLEEP_CFG_SCHEN | MMA9551_SLEEP_CFG_SNCEN,
MMA9551_SLEEP_CFG_SCHEN);
return mma9551_set_device_state(data->client, true);
}

static int mma9551_gpio_probe(struct iio_dev *indio_dev)
Expand Down Expand Up @@ -869,8 +935,19 @@ static int mma9551_probe(struct i2c_client *client,
goto out_poweroff;
}

ret = pm_runtime_set_active(&client->dev);
if (ret < 0)
goto out_iio_unregister;

pm_runtime_enable(&client->dev);
pm_runtime_set_autosuspend_delay(&client->dev,
MMA9551_AUTO_SUSPEND_DELAY_MS);
pm_runtime_use_autosuspend(&client->dev);

return 0;

out_iio_unregister:
iio_device_unregister(indio_dev);
out_poweroff:
mma9551_set_device_state(client, false);

Expand All @@ -882,6 +959,10 @@ static int mma9551_remove(struct i2c_client *client)
struct iio_dev *indio_dev = i2c_get_clientdata(client);
struct mma9551_data *data = iio_priv(indio_dev);

pm_runtime_disable(&client->dev);
pm_runtime_set_suspended(&client->dev);
pm_runtime_put_noidle(&client->dev);

iio_device_unregister(indio_dev);
mutex_lock(&data->mutex);
mma9551_set_device_state(data->client, false);
Expand All @@ -890,37 +971,72 @@ static int mma9551_remove(struct i2c_client *client)
return 0;
}

#ifdef CONFIG_PM
static int mma9551_runtime_suspend(struct device *dev)
{
struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
struct mma9551_data *data = iio_priv(indio_dev);
int ret;

mutex_lock(&data->mutex);
ret = mma9551_set_device_state(data->client, false);
mutex_unlock(&data->mutex);
if (ret < 0) {
dev_err(&data->client->dev, "powering off device failed\n");
return -EAGAIN;
}

return 0;
}

static int mma9551_runtime_resume(struct device *dev)
{
struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
struct mma9551_data *data = iio_priv(indio_dev);
int ret;

ret = mma9551_set_device_state(data->client, true);
if (ret < 0)
return ret;

mma9551_sleep(MMA9551_DEFAULT_SAMPLE_RATE);

return 0;
}
#endif

#ifdef CONFIG_PM_SLEEP
static int mma9551_suspend(struct device *dev)
{
struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
struct mma9551_data *data = iio_priv(indio_dev);
int ret;

mutex_lock(&data->mutex);
mma9551_set_device_state(data->client, false);
ret = mma9551_set_device_state(data->client, false);
mutex_unlock(&data->mutex);

return 0;
return ret;
}

static int mma9551_resume(struct device *dev)
{
struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
struct mma9551_data *data = iio_priv(indio_dev);
int ret;

mutex_lock(&data->mutex);
mma9551_set_device_state(data->client, true);
ret = mma9551_set_device_state(data->client, true);
mutex_unlock(&data->mutex);

return 0;
return ret;
}
#else
#define mma9551_suspend NULL
#define mma9551_resume NULL
#endif

static const struct dev_pm_ops mma9551_pm_ops = {
SET_SYSTEM_SLEEP_PM_OPS(mma9551_suspend, mma9551_resume)
SET_RUNTIME_PM_OPS(mma9551_runtime_suspend,
mma9551_runtime_resume, NULL)
};

static const struct acpi_device_id mma9551_acpi_match[] = {
Expand Down

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