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drivers: sensor: ccs811: bypass APP_START when not in boot mode

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The CCS811 can be in either boot mode (after powerup) or application
mode, and these modes have distinct register maps that share only some
content.  The register written to switch from boot mode to application
mode is not available in application mode, so don't write to it in that
case.

Also respect the required timeout between APP_START and next I2C
operation.

Signed-off-by: Peter A. Bigot <pab@pabigot.com>
This commit is contained in:
Peter A. Bigot 2018-11-20 08:47:19 -06:00 • committed by Maureen Helm
commit 463bec1749
1 changed files with 7 additions and 0 deletions
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7
drivers/sensor/ccs811/ccs811.c
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@ -158,6 +158,12 @@ static int switch_to_app_mode(struct device *i2c)
return -EINVAL;
}
/* Check if already in application mode */
if (status & CCS811_STATUS_FW_MODE) {
LOG_DBG("CCS811 Already in application mode");
return 0;
}
buf = CCS811_REG_APP_START;
/* Set the device to application mode */
if (i2c_write(i2c, &buf, 1, DT_INST_0_AMS_CCS811_BASE_ADDRESS) < 0) {
@ -165,6 +171,7 @@ static int switch_to_app_mode(struct device *i2c)
return -EIO;
}
k_sleep(1); /* t_APP_START */
if (i2c_reg_read_byte(i2c, DT_INST_0_AMS_CCS811_BASE_ADDRESS,
CCS811_REG_STATUS, &status) < 0) {
LOG_ERR("Failed to read Status register");