Commit f764c293 authored by Javier Carrasco's avatar Javier Carrasco Committed by Jonathan Cameron
Browse files

iio: humidity: hdc3020: add power management 



The HDC3020 sensor carries out periodic measurements during normal
operation, but as long as the power supply is enabled, it will carry on
in low-power modes. In order to avoid that and reduce power consumption,
the device can be switched to Trigger-on Demand mode, and if possible,
turn off its regulator.

According to the datasheet, the maximum "Power Up Ready" is 5 ms.

Add resume/suspend pm operations to manage measurement mode and
regulator state.

Signed-off-by: default avatarJavier Carrasco <javier.carrasco.cruz@gmail.com>
Link: https://lore.kernel.org/r/20240303-hdc3020-pm-v3-1-48bc02b5241b@gmail.com


Signed-off-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
parent d1efcf88

drivers/iio/humidity/hdc3020.c

+76 −19
Original line number Diff line number Diff line
@@ -20,6 +20,8 @@ 
#include <linux/interrupt.h>

#include <linux/module.h>

#include <linux/mutex.h>

#include <linux/pm.h>

#include <linux/regulator/consumer.h>

#include <linux/units.h>



#include <asm/unaligned.h>
@@ -68,6 +70,7 @@ 


struct hdc3020_data {

	struct i2c_client *client;

	struct regulator *vdd_supply;

	/*

	 * Ensure that the sensor configuration (currently only heater is

	 * supported) will not be changed during the process of reading
@@ -551,9 +554,45 @@ static const struct iio_info hdc3020_info = { 
	.write_event_value = hdc3020_write_thresh,

};



static void hdc3020_stop(void *data)

static int hdc3020_power_off(struct hdc3020_data *data)

{

	hdc3020_exec_cmd((struct hdc3020_data *)data, HDC3020_EXIT_AUTO);

	hdc3020_exec_cmd(data, HDC3020_EXIT_AUTO);



	return regulator_disable(data->vdd_supply);

}



static int hdc3020_power_on(struct hdc3020_data *data)

{

	int ret;



	ret = regulator_enable(data->vdd_supply);

	if (ret)

		return ret;



	fsleep(5000);



	if (data->client->irq) {

		/*

		 * The alert output is activated by default upon power up,

		 * hardware reset, and soft reset. Clear the status register.

		 */

		ret = hdc3020_exec_cmd(data, HDC3020_S_STATUS);

		if (ret) {

			hdc3020_power_off(data);

			return ret;

		}

	}



	ret = hdc3020_exec_cmd(data, HDC3020_S_AUTO_10HZ_MOD0);

	if (ret)

		hdc3020_power_off(data);



	return ret;

}



static void hdc3020_exit(void *data)

{

	hdc3020_power_off(data);

}



static int hdc3020_probe(struct i2c_client *client)
@@ -569,6 +608,8 @@ static int hdc3020_probe(struct i2c_client *client) 
	if (!indio_dev)

		return -ENOMEM;



	dev_set_drvdata(&client->dev, indio_dev);



	data = iio_priv(indio_dev);

	data->client = client;

	mutex_init(&data->lock);
@@ -580,6 +621,20 @@ static int hdc3020_probe(struct i2c_client *client) 
	indio_dev->info = &hdc3020_info;

	indio_dev->channels = hdc3020_channels;

	indio_dev->num_channels = ARRAY_SIZE(hdc3020_channels);



	data->vdd_supply = devm_regulator_get(&client->dev, "vdd");

	if (IS_ERR(data->vdd_supply))

		return dev_err_probe(&client->dev, PTR_ERR(data->vdd_supply),

				     "Unable to get VDD regulator\n");



	ret = hdc3020_power_on(data);

	if (ret)

		return dev_err_probe(&client->dev, ret, "Power on failed\n");



	ret = devm_add_action_or_reset(&data->client->dev, hdc3020_exit, data);

	if (ret)

		return ret;



	if (client->irq) {

		ret = devm_request_threaded_irq(&client->dev, client->irq,

						NULL, hdc3020_interrupt_handler,
@@ -588,25 +643,8 @@ static int hdc3020_probe(struct i2c_client *client) 
		if (ret)

			return dev_err_probe(&client->dev, ret,

					     "Failed to request IRQ\n");



		/*

		 * The alert output is activated by default upon power up,

		 * hardware reset, and soft reset. Clear the status register.

		 */

		ret = hdc3020_exec_cmd(data, HDC3020_S_STATUS);

		if (ret)

			return ret;

	}



	ret = hdc3020_exec_cmd(data, HDC3020_S_AUTO_10HZ_MOD0);

	if (ret)

		return dev_err_probe(&client->dev, ret,

				     "Unable to set up measurement\n");



	ret = devm_add_action_or_reset(&data->client->dev, hdc3020_stop, data);

	if (ret)

		return ret;



	ret = devm_iio_device_register(&data->client->dev, indio_dev);

	if (ret)

		return dev_err_probe(&client->dev, ret, "Failed to add device");
@@ -614,6 +652,24 @@ static int hdc3020_probe(struct i2c_client *client) 
	return 0;

}



static int hdc3020_suspend(struct device *dev)

{

	struct iio_dev *iio_dev = dev_get_drvdata(dev);

	struct hdc3020_data *data = iio_priv(iio_dev);



	return hdc3020_power_off(data);

}



static int hdc3020_resume(struct device *dev)

{

	struct iio_dev *iio_dev = dev_get_drvdata(dev);

	struct hdc3020_data *data = iio_priv(iio_dev);



	return hdc3020_power_on(data);

}



static DEFINE_SIMPLE_DEV_PM_OPS(hdc3020_pm_ops, hdc3020_suspend, hdc3020_resume);



static const struct i2c_device_id hdc3020_id[] = {

	{ "hdc3020" },

	{ "hdc3021" },
@@ -633,6 +689,7 @@ MODULE_DEVICE_TABLE(of, hdc3020_dt_ids); 
static struct i2c_driver hdc3020_driver = {

	.driver = {

		.name = "hdc3020",

		.pm = pm_sleep_ptr(&hdc3020_pm_ops),

		.of_match_table = hdc3020_dt_ids,

	},

	.probe = hdc3020_probe,