Hi Colin, Colin Foe-Parker <colin.foeparker@xxxxxxxxx> schrieb am Fri, 25. Aug 08:15: > Hi Andreas, > > On Thu, Aug 24, 2017 at 10:52 PM, Andreas Klinger <ak@xxxxxxxxxxxxx> wrote: > > Hi Colin, > > > > Colin Parker <colin.foeparker@xxxxxxxxx> schrieb am Thu, 24. Aug 16:54: > >> From: Colin Parker <colin.parker@xxxxxxxxx> > >> > >> This results in inaccurate Humidity readings that tend to not fluxuate. > >> > >> Update the ordering of the register writes so that ctrl_meas is written > >> after ctrl_hum. This is taken from section 5.4.3 of the datasheet. > >> > >> "https://ae-bst.resource.bosch.com/media/_tech/media/datasheets/BST-BME280_DS001-11.pdf"; > > > > this part of the patch is already covered by commit afb2c3851b: "iio: bmp280: > > properly initialize device for humidity reading" > > Thanks for pointing out the duplication of efforts! I dug through the > fixes-togreg branch and found the changes you are referencing. > > I think that there might still be an issue there. I believe that the > regmap_update_bits function will only write to the ctrl_meas register > if there is a difference in the register value vs what is in the > regmap cache. So in the situation where someone wanted to update the > humidity sampling configuration, I don't think the write to the > ctrl_meas write would go out on the bus. And as a consequence, the > changes to the humidity settings wouldn't become effective. > > What is your take? I can refactor my patch to just fix that part if > you see the same bug. Yes, i can see this bug, but i haven't tried so far. It's really worth to send it out as a patch Andreas > > -Colin > > > > > Andreas > > > >> > >> Also writes to the config register can be ignored if the device is in Normal Mode. > >> Change the device to sleep mode before updating the config register. > >> This has the nice side effect of guaranteeing that the regmap_update_bits > >> function actually updates the driver and not just verifies the setting in its cache. > >> > >> Signed-off-by: Colin Parker <colin.parker@xxxxxxxxx> > >> --- > >> drivers/iio/pressure/bmp280-core.c | 22 +++++++++++++++------- > >> 1 file changed, 15 insertions(+), 7 deletions(-) > >> > >> diff --git a/drivers/iio/pressure/bmp280-core.c b/drivers/iio/pressure/bmp280-core.c > >> index d82b788..85aa24c 100644 > >> --- a/drivers/iio/pressure/bmp280-core.c > >> +++ b/drivers/iio/pressure/bmp280-core.c > >> @@ -559,10 +559,7 @@ static int bmp280_chip_config(struct bmp280_data *data) > >> BMP280_OSRS_PRESS_X(data->oversampling_press + 1); > >> > >> ret = regmap_update_bits(data->regmap, BMP280_REG_CTRL_MEAS, > >> - BMP280_OSRS_TEMP_MASK | > >> - BMP280_OSRS_PRESS_MASK | > >> - BMP280_MODE_MASK, > >> - osrs | BMP280_MODE_NORMAL); > >> + BMP280_MODE_MASK, BMP280_MODE_SLEEP); > >> if (ret < 0) { > >> dev_err(data->dev, > >> "failed to write ctrl_meas register\n"); > >> @@ -578,6 +575,17 @@ static int bmp280_chip_config(struct bmp280_data *data) > >> return ret; > >> } > >> > >> + ret = regmap_update_bits(data->regmap, BMP280_REG_CTRL_MEAS, > >> + BMP280_OSRS_TEMP_MASK | > >> + BMP280_OSRS_PRESS_MASK | > >> + BMP280_MODE_MASK, > >> + osrs | BMP280_MODE_NORMAL); > >> + if (ret < 0) { > >> + dev_err(data->dev, > >> + "failed to write ctrl_meas register\n"); > >> + return ret; > >> + } > >> + > >> return ret; > >> } > >> > >> @@ -597,14 +605,14 @@ static const struct bmp280_chip_info bmp280_chip_info = { > >> > >> static int bme280_chip_config(struct bmp280_data *data) > >> { > >> - int ret = bmp280_chip_config(data); > >> u8 osrs = BMP280_OSRS_HUMIDITIY_X(data->oversampling_humid + 1); > >> + int ret = regmap_update_bits(data->regmap, BMP280_REG_CTRL_HUMIDITY, > >> + BMP280_OSRS_HUMIDITY_MASK, osrs); > >> > >> if (ret < 0) > >> return ret; > >> > >> - return regmap_update_bits(data->regmap, BMP280_REG_CTRL_HUMIDITY, > >> - BMP280_OSRS_HUMIDITY_MASK, osrs); > >> + return bmp280_chip_config(data); > >> } > >> > >> static const struct bmp280_chip_info bme280_chip_info = { > >> -- > >> 2.1.4 > >> > >> -- > >> To unsubscribe from this list: send the line "unsubscribe linux-iio" in > >> the body of a message to majordomo@xxxxxxxxxxxxxxx > >> More majordomo info at http://vger.kernel.org/majordomo-info.html > > > > -- > > > > -- > Colin Parker > > > ACLIMA INC > > Direct (415) 735-5062 | Email colin.foeparker@xxxxxxxxx > > 10 Lombard St. Suite 250 | San Francisco, CA 94111 > > > Hello, we're Aclima. > > > This email and any attachments may contain private, confidential and > privileged material for the sole use of the intended recipient. If you > are not the intended recipient, please immediately delete this email > and any attachments. -- Andreas Klinger Grabenreith 27 84508 Burgkirchen +49 8623 919966 ak@xxxxxxxxxxxxx www.it-klinger.de www.grabenreith.de -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
