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drivers: sensor: ccs811: deassert WAKEn when not active

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Asserting the WAKEn increases current draw.  Turn it off when I2C is
not being used.

Signed-off-by: Peter A. Bigot <pab@pabigot.com>
Signed-off-by: Carles Cufi <carles.cufi@nordicsemi.no>
This commit is contained in:
Peter A. Bigot 2018-11-19 23:02:30 -06:00 • committed by Maureen Helm
commit cc3020ea49
1 changed files with 40 additions and 12 deletions
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52
drivers/sensor/ccs811/ccs811.c
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@ -19,37 +19,55 @@
LOG_MODULE_REGISTER(CCS811, CONFIG_SENSOR_LOG_LEVEL); LOG_MODULE_REGISTER(CCS811, CONFIG_SENSOR_LOG_LEVEL);
#ifdef DT_INST_0_AMS_CCS811_WAKE_GPIOS_CONTROLLER
static void set_wake(struct ccs811_data *drv_data, bool enable)
{
/* Always active-low */
gpio_pin_write(drv_data->gpio, DT_INST_0_AMS_CCS811_WAKE_GPIOS_PIN, !enable);
if (enable) {
k_busy_wait(50); /* t_WAKE = 50 us */
} else {
k_busy_wait(20); /* t_DWAKE = 20 us */
}
}
#else
#define set_wake(...)
#endif
static int ccs811_sample_fetch(struct device *dev, enum sensor_channel chan) static int ccs811_sample_fetch(struct device *dev, enum sensor_channel chan)
{ {
struct ccs811_data *drv_data = dev->driver_data; struct ccs811_data *drv_data = dev->driver_data;
int tries = 11; int tries = 11;
u16_t buf[4]; u16_t buf[4];
u8_t status; u8_t status;
int rv = -EIO;
/* Check data ready flag for the measurement interval of 1 seconds */ /* Check data ready flag for the measurement interval of 1 seconds */
while (tries-- > 0) { while (tries-- > 0) {
set_wake(drv_data, true);
if (i2c_reg_read_byte(drv_data->i2c, DT_INST_0_AMS_CCS811_BASE_ADDRESS, if (i2c_reg_read_byte(drv_data->i2c, DT_INST_0_AMS_CCS811_BASE_ADDRESS,
CCS811_REG_STATUS, &status) < 0) { CCS811_REG_STATUS, &status) < 0) {
LOG_ERR("Failed to read Status register"); LOG_ERR("Failed to read Status register");
return -EIO; goto out;
} }
if ((status & CCS811_STATUS_DATA_READY) || tries == 0) { if ((status & CCS811_STATUS_DATA_READY) || tries == 0) {
break; break;
} }
set_wake(drv_data, false);
k_sleep(K_MSEC(100)); k_sleep(K_MSEC(100));
} }
if (!(status & CCS811_STATUS_DATA_READY)) { if (!(status & CCS811_STATUS_DATA_READY)) {
LOG_ERR("Sensor data not available"); LOG_ERR("Sensor data not available");
return -EIO; goto out;
} }
if (i2c_burst_read(drv_data->i2c, DT_INST_0_AMS_CCS811_BASE_ADDRESS, if (i2c_burst_read(drv_data->i2c, DT_INST_0_AMS_CCS811_BASE_ADDRESS,
CCS811_REG_ALG_RESULT_DATA, (u8_t *)buf, 8) < 0) { CCS811_REG_ALG_RESULT_DATA, (u8_t *)buf, 8) < 0) {
LOG_ERR("Failed to read conversion data."); LOG_ERR("Failed to read conversion data.");
return -EIO; goto out;
} }
drv_data->co2 = sys_be16_to_cpu(buf[0]); drv_data->co2 = sys_be16_to_cpu(buf[0]);
@ -57,8 +75,11 @@ static int ccs811_sample_fetch(struct device *dev, enum sensor_channel chan)
drv_data->status = buf[2] & 0xff; drv_data->status = buf[2] & 0xff;
drv_data->error = buf[2] >> 8; drv_data->error = buf[2] >> 8;
drv_data->resistance = sys_be16_to_cpu(buf[3]); drv_data->resistance = sys_be16_to_cpu(buf[3]);
rv = 0;
return 0; out:
set_wake(drv_data, false);
return rv;
} }
static int ccs811_channel_get(struct device *dev, static int ccs811_channel_get(struct device *dev,
@ -211,8 +232,8 @@ int ccs811_init(struct device *dev)
#ifdef DT_INST_0_AMS_CCS811_WAKE_GPIOS_PIN #ifdef DT_INST_0_AMS_CCS811_WAKE_GPIOS_PIN
gpio_pin_configure(drv_data->gpio, DT_INST_0_AMS_CCS811_WAKE_GPIOS_PIN, gpio_pin_configure(drv_data->gpio, DT_INST_0_AMS_CCS811_WAKE_GPIOS_PIN,
GPIO_DIR_OUT); GPIO_DIR_OUT);
gpio_pin_write(drv_data->gpio, DT_INST_0_AMS_CCS811_WAKE_GPIOS_PIN, 0);
set_wake(drv_data, true);
k_sleep(K_MSEC(1)); k_sleep(K_MSEC(1));
#endif #endif
} }
@ -220,19 +241,21 @@ int ccs811_init(struct device *dev)
/* Switch device to application mode */ /* Switch device to application mode */
ret = switch_to_app_mode(drv_data->i2c); ret = switch_to_app_mode(drv_data->i2c);
if (ret) { if (ret) {
return ret; goto out;
} }
/* Check Hardware ID */ /* Check Hardware ID */
if (i2c_reg_read_byte(drv_data->i2c, DT_INST_0_AMS_CCS811_BASE_ADDRESS, if (i2c_reg_read_byte(drv_data->i2c, DT_INST_0_AMS_CCS811_BASE_ADDRESS,
CCS811_REG_HW_ID, &hw_id) < 0) { CCS811_REG_HW_ID, &hw_id) < 0) {
LOG_ERR("Failed to read Hardware ID register"); LOG_ERR("Failed to read Hardware ID register");
return -EIO; ret = -EIO;
goto out;
} }
if (hw_id != CCS881_HW_ID) { if (hw_id != CCS881_HW_ID) {
LOG_ERR("Hardware ID mismatch!"); LOG_ERR("Hardware ID mismatch!");
return -EINVAL; ret = -EINVAL;
goto out;
} }
/* Set Measurement mode for 1 second */ /* Set Measurement mode for 1 second */
@ -240,22 +263,27 @@ int ccs811_init(struct device *dev)
CCS811_REG_MEAS_MODE, CCS811_REG_MEAS_MODE,
CCS811_MODE_IAQ_1SEC) < 0) { CCS811_MODE_IAQ_1SEC) < 0) {
LOG_ERR("Failed to set Measurement mode"); LOG_ERR("Failed to set Measurement mode");
return -EIO; ret = -EIO;
goto out;
} }
/* Check for error */ /* Check for error */
if (i2c_reg_read_byte(drv_data->i2c, DT_INST_0_AMS_CCS811_BASE_ADDRESS, if (i2c_reg_read_byte(drv_data->i2c, DT_INST_0_AMS_CCS811_BASE_ADDRESS,
CCS811_REG_STATUS, &status) < 0) { CCS811_REG_STATUS, &status) < 0) {
LOG_ERR("Failed to read Status register"); LOG_ERR("Failed to read Status register");
return -EIO; ret = -EIO;
goto out;
} }
if (status & CCS811_STATUS_ERROR) { if (status & CCS811_STATUS_ERROR) {
LOG_ERR("Error occurred during sensor configuration"); LOG_ERR("Error occurred during sensor configuration");
return -EINVAL; ret = -EINVAL;
goto out;
} }
return 0; out:
set_wake(drv_data, false);
return ret;
} }
static struct ccs811_data ccs811_driver; static struct ccs811_data ccs811_driver;