linux-toradex.git/drivers/iio/chemical/bme680_core.c, branch v6.11

iio: chemical: bme680: Fix sensor data read operation

2024-06-09T11:02:34+00:00

A read operation is happening as follows:

a) Set sensor to forced mode
b) Sensor measures values and update data registers and sleeps again
c) Read data registers

In the current implementation the read operation happens immediately
after the sensor is set to forced mode so the sensor does not have
the time to update properly the registers. This leads to the following
2 problems:

1) The first ever value which is read by the register is always wrong
2) Every read operation, puts the register into forced mode and reads
the data that were calculated in the previous conversion.

This behaviour was tested in 2 ways:

1) The internal meas_status_0 register was read before and after every
read operation in order to verify that the data were ready even before
the register was set to forced mode and also to check that after the
forced mode was set the new data were not yet ready.

2) Physically changing the temperature and measuring the temperature

This commit adds the waiting time in between the set of the forced mode
and the read of the data. The function is taken from the Bosch BME68x
Sensor API [1].

[1]: https://github.com/boschsensortec/BME68x_SensorAPI/blob/v4.4.8/bme68x.c#L490

Fixes: 1b3bd8592780 ("iio: chemical: Add support for Bosch BME680 sensor")
Signed-off-by: Vasileios Amoiridis 
Link: https://lore.kernel.org/r/20240606212313.207550-5-vassilisamir@gmail.com
Cc: 
Signed-off-by: Jonathan Cameron

iio: chemical: bme680: Fix overflows in compensate() functions

2024-06-09T11:02:13+00:00

There are cases in the compensate functions of the driver that
there could be overflows of variables due to bit shifting ops.
These implications were initially discussed here [1] and they
were mentioned in log message of Commit 1b3bd8592780 ("iio:
chemical: Add support for Bosch BME680 sensor").

[1]: https://lore.kernel.org/linux-iio/20180728114028.3c1bbe81@archlinux/

Fixes: 1b3bd8592780 ("iio: chemical: Add support for Bosch BME680 sensor")
Signed-off-by: Vasileios Amoiridis 
Link: https://lore.kernel.org/r/20240606212313.207550-4-vassilisamir@gmail.com
Cc: 
Signed-off-by: Jonathan Cameron

iio: chemical: bme680: Fix calibration data variable

2024-06-09T10:58:32+00:00

According to the BME68x Sensor API [1], the h6 calibration
data variable should be an unsigned integer of size 8.

[1]: https://github.com/boschsensortec/BME68x_SensorAPI/blob/v4.4.8/bme68x_defs.h#L789

Fixes: 1b3bd8592780 ("iio: chemical: Add support for Bosch BME680 sensor")
Signed-off-by: Vasileios Amoiridis 
Link: https://lore.kernel.org/r/20240606212313.207550-3-vassilisamir@gmail.com
Cc: 
Signed-off-by: Jonathan Cameron

iio: chemical: bme680: Fix pressure value output

2024-06-09T10:57:32+00:00

The IIO standard units are measured in kPa while the driver
is using hPa.

Apart from checking the userspace value itself, it is mentioned also
in the Bosch API [1] that the pressure value is in Pascal.

[1]: https://github.com/boschsensortec/BME68x_SensorAPI/blob/v4.4.8/bme68x_defs.h#L742

Fixes: 1b3bd8592780 ("iio: chemical: Add support for Bosch BME680 sensor")
Signed-off-by: Vasileios Amoiridis 
Link: https://lore.kernel.org/r/20240606212313.207550-2-vassilisamir@gmail.com
Cc: 
Signed-off-by: Jonathan Cameron

iio: chemical: bme680: fix typo in comment

2022-06-11T13:35:27+00:00

Spelling mistake (triple letters) in comment.
Detected with the help of Coccinelle.

Signed-off-by: Julia Lawall 
Link: https://lore.kernel.org/r/20220521111145.81697-68-Julia.Lawall@inria.fr
Signed-off-by: Jonathan Cameron

iio:chemical:bme680: Move exports to IIO_BME680 namespace

2022-02-18T11:42:27+00:00

In order to avoid unnecessary pollution of the global symbol namespace
move the common/library functions into a specific namespace and import
that into the bus specific device drivers that use them.

For more information see https://lwn.net/Articles/760045/

Signed-off-by: Jonathan Cameron 
Cc: Himanshu Jha 
Reviewed-by: Andy Shevchenko 
Link: https://lore.kernel.org/r/20220130205701.334592-17-jic23@kernel.org

iio: bme680: Use DIV_ROUND_CLOSEST() instead of open-coding it

2021-01-09T21:52:45+00:00

Use DIV_ROUND_CLOSEST() instead of open-coding it. This documents intent
and makes it more clear what is going on for the casual reviewer.

Generated using the following the Coccinelle semantic patch.

// 
@r1@
expression x;
constant C1;
constant C2;
@@
 ((x) + C1) / C2

@script:python@
C1 << r1.C1;
C2 << r1.C2;
@@
try:
	if int(C1) * 2 != int(C2):
		cocci.include_match(False)
except:
	cocci.include_match(False)

@@
expression r1.x;
constant r1.C1;
constant r1.C2;
@@
-(((x) + C1) / C2)
+DIV_ROUND_CLOSEST(x, C2)
// 

Signed-off-by: Lars-Peter Clausen 
Link: https://lore.kernel.org/r/20201227171126.28216-2-lars@metafoo.de
Signed-off-by: Jonathan Cameron

iio: remove explicit IIO device parent assignment

2020-06-14T10:49:59+00:00

This patch applies the semantic patch:
@@
expression I, P, SP;
@@
   I = devm_iio_device_alloc(P, SP);
   ...
-  I->dev.parent = P;

It updates 302 files and does 307 deletions.
This semantic patch also removes some comments like
'/* Establish that the iio_dev is a child of the i2c device */'

But this is is only done in case where the block is left empty.

The patch does not seem to cover all cases. It looks like in some cases a
different variable is used in some cases to assign the parent, but it
points to the same reference.
In other cases, the block covered by ... may be just too big to be covered
by the semantic patch.

However, this looks pretty good as well, as it does cover a big bulk of the
drivers that should remove the parent assignment.

Signed-off-by: Alexandru Ardelean 
Signed-off-by: Jonathan Cameron

iio:chemical:bme680: Tidy up parameters to regmap_bulk_read

2020-04-19T15:56:39+00:00

A mixture of:
* Unnecessary casts of val parameter to u8 * which makes little sense as
  the function take a void *.
* Explicit sizes where we can use the destination type to define that.
  Note that's not true in all cases as we do read 3 bytes into 4 byte
  destinations.

Note that noting was broken here, I'm just trying to ensure this doesn't
get cut and paste into more drivers so cleaning these out subsystem wide.

Signed-off-by: Jonathan Cameron 
Acked-by: Himanshu Jha 
Reviewed-by: Andy Shevchenko 
Reviewed-by: Alexandru Ardelean

iio:chemical:bme680: Fix SPI read interface

2019-03-09T17:27:36+00:00

The SPI interface implementation was completely broken.

When using the SPI interface, there are only 7 address bits, the upper bit
is controlled by a page select register. The core needs access to both
ranges, so implement register read/write for both regions. The regmap
paging functionality didn't agree with a register that needs to be read
and modified, so I implemented a custom paging algorithm.

This fixes that the device wouldn't even probe in SPI mode.

The SPI interface then isn't different from I2C, merged them into the core,
and the I2C/SPI named registers are no longer needed.

Implemented register value caching for the registers to reduce the I2C/SPI
data transfers considerably.

The calibration set reads as all zeroes until some undefined point in time,
and I couldn't determine what makes it valid. The datasheet mentions these
registers but does not provide any hints on when they become valid, and they
aren't even enumerated in the memory map. So check the calibration and
retry reading it from the device after each measurement until it provides
something valid.

Despite the size this is suitable for a stable backport given that
it seems the SPI support never worked.

Signed-off-by: Mike Looijmans 
Fixes: 1b3bd8592780 ("iio: chemical: Add support for Bosch BME680 sensor");
Cc: 
Signed-off-by: Jonathan Cameron