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iio: humidity: hdc3020: add reset management

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The HDC3020 provides an active low reset signal that must be handled if
connected. Asserting this signal turns the device into Trigger-on Demand
measurement mode, reducing its power consumption when no measurements
are required like in low-power modes.

According to the datasheet, the longest "Reset Ready" is 3 ms, which is
only taken into account if the reset signal is defined.

Signed-off-by: Javier Carrasco <javier.carrasco.cruz@gmail.com>
Link: https://lore.kernel.org/r/20240303-hdc3020-pm-v3-3-48bc02b5241b@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This commit is contained in:
Javier Carrasco 2024-03-03 22:54:22 +01:00 committed by Jonathan Cameron
parent 137166ef5f
commit e264b086f4
1 changed files with 16 additions and 0 deletions
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16
drivers/iio/humidity/hdc3020.c
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@ -15,6 +15,7 @@
#include <linux/cleanup.h> #include <linux/cleanup.h>
#include <linux/crc8.h> #include <linux/crc8.h>
#include <linux/delay.h> #include <linux/delay.h>
#include <linux/gpio/consumer.h>
#include <linux/i2c.h> #include <linux/i2c.h>
#include <linux/init.h> #include <linux/init.h>
#include <linux/interrupt.h> #include <linux/interrupt.h>
@ -70,6 +71,7 @@
struct hdc3020_data { struct hdc3020_data {
struct i2c_client *client; struct i2c_client *client;
struct gpio_desc *reset_gpio;
struct regulator *vdd_supply; struct regulator *vdd_supply;
/* /*
* Ensure that the sensor configuration (currently only heater is * Ensure that the sensor configuration (currently only heater is
@ -558,6 +560,9 @@ static int hdc3020_power_off(struct hdc3020_data *data)
{ {
hdc3020_exec_cmd(data, HDC3020_EXIT_AUTO); hdc3020_exec_cmd(data, HDC3020_EXIT_AUTO);
if (data->reset_gpio)
gpiod_set_value_cansleep(data->reset_gpio, 1);
return regulator_disable(data->vdd_supply); return regulator_disable(data->vdd_supply);
} }
@ -571,6 +576,11 @@ static int hdc3020_power_on(struct hdc3020_data *data)
fsleep(5000); fsleep(5000);
if (data->reset_gpio) {
gpiod_set_value_cansleep(data->reset_gpio, 0);
fsleep(3000);
}
if (data->client->irq) { if (data->client->irq) {
/* /*
* The alert output is activated by default upon power up, * The alert output is activated by default upon power up,
@ -627,6 +637,12 @@ static int hdc3020_probe(struct i2c_client *client)
return dev_err_probe(&client->dev, PTR_ERR(data->vdd_supply), return dev_err_probe(&client->dev, PTR_ERR(data->vdd_supply),
"Unable to get VDD regulator\n"); "Unable to get VDD regulator\n");
data->reset_gpio = devm_gpiod_get_optional(&client->dev, "reset",
GPIOD_OUT_HIGH);
if (IS_ERR(data->reset_gpio))
return dev_err_probe(&client->dev, PTR_ERR(data->reset_gpio),
"Cannot get reset GPIO\n");
ret = hdc3020_power_on(data); ret = hdc3020_power_on(data);
if (ret) if (ret)
return dev_err_probe(&client->dev, ret, "Power on failed\n"); return dev_err_probe(&client->dev, ret, "Power on failed\n");