Hello, As part of a previous discussion with Jonathan (I know, it was three months ago, sorry for the delay :-$), it appeared necessary to do a little bit of cleanup in the IIO core and at least provide a little bit more documentation for developers diving into the IIO subsystem for the first time. My first move was to write a blog post trying to explain (from my point of view but with the review of Jonathan) what is necessary to understand when writing and IIO kernel driver: https://bootlin.com/blog/the-backbone-of-a-linux-industrial-i-o-driver/ Here is now the second halve of this work, with few things that I tried to address. * The currentmode indio_dev entry was misused by several device drivers, I tried to understand which ones were wrong (there are two still accessing this variable left, I decided not to touch them because I think it is legitimate) and I tried to find an alternative. * Then, I tried to make new accesses to this variable harder in order to avoid future mistakes, by creating a helper to read it from outside the core and moving it to the opaque structure. * I continued with the IIO modes which are completely undocumented. Following a few exchanges with Jonathan, I tried to take most of this discussion and put it into a kernel doc header. * When doing the above task, I realized that there was a particular case handled for kfifo buffers which I tried to simplify, but if this is a mistake, I'll just drop the patch. Hope this will help! Cheers, Miquèl Changes in v3: * Added a patch to cleanup the _write_raw() callbacks in the st_sensor drivers. Returned as early as possible. * Updated the description of INDIO_DIRECT_MODE and INDIO_BUFFER_SOFTWARE as discussed. * Added the R-by from Fabrice. * Extended the coverage of the odr lock in order to avoid relying on the iio_device_claim_direct_mode() helper implementation for that. Changes in v2: * Added Alexandru Reviewed-by when relevant. * Indicated that "modes" is a bitmask as suggested. * Added a mention in the "modes" kdoc about the function that could alter its content in the core. * Added more driver maintainers in Cc. * Avoided deleting the INDIO_BUFFER_TRIGGERED mode from kfifos. * Dropped entirely the currentmode setter helper. * Avoided using the currentmode getter from places where we have access to the opaque structure (ie. from the core itself). * Added a patch to move the iio_buffer_enabled() definition in the core as it cannot be inlined anymore. * Dropped completely the use of the mlock lock form the st-sensor drivers by inserting an additional local lock when this was needed. Hopefully I didn't fail that, this will need testing. * Reworded the modes kdoc as advised by Jonathan. Miquel Raynal (13): iio: core: Enhance the kernel doc of modes and currentmodes iio_dev entries iio: magnetometer: rm3100: Stop abusing the ->currentmode iio: adc: stm32-dfsdm: Avoid dereferencing ->currentmode iio: st_sensors: Return as early as possible from the _write_raw() callbacks iio: st_sensors: Drop the protection on _avail functions iio: st_sensors: Add a local lock for protecting odr iio: st_sensors: Stop abusing mlock to ensure internal coherency iio: st_sensors: Use iio_device_claim/release_direct_mode() when relevant iio: Un-inline iio_buffer_enabled() iio: core: Hide read accesses to iio_dev->currentmode iio: core: Move the currentmode entry to the opaque structure iio: core: Simplify the registration of kfifo buffers iio: core: Clarify the modes drivers/iio/accel/bmc150-accel-core.c | 4 +- drivers/iio/accel/fxls8962af-core.c | 1 - drivers/iio/accel/sca3000.c | 1 - drivers/iio/accel/ssp_accel_sensor.c | 1 - drivers/iio/accel/st_accel_core.c | 13 +--- drivers/iio/adc/at91-sama5d2_adc.c | 4 +- drivers/iio/adc/ina2xx-adc.c | 1 - drivers/iio/adc/stm32-dfsdm-adc.c | 5 +- drivers/iio/adc/ti_am335x_adc.c | 4 +- drivers/iio/buffer/kfifo_buf.c | 10 +-- .../cros_ec_sensors/cros_ec_sensors_core.c | 3 +- drivers/iio/common/scmi_sensors/scmi_iio.c | 1 - .../iio/common/st_sensors/st_sensors_core.c | 50 +++++++------ drivers/iio/gyro/ssp_gyro_sensor.c | 1 - drivers/iio/gyro/st_gyro_core.c | 15 ++-- drivers/iio/health/max30100.c | 1 - drivers/iio/health/max30102.c | 1 - .../iio/imu/inv_icm42600/inv_icm42600_accel.c | 1 - .../iio/imu/inv_icm42600/inv_icm42600_gyro.c | 1 - .../iio/imu/st_lsm6dsx/st_lsm6dsx_buffer.c | 1 - drivers/iio/industrialio-buffer.c | 12 ++-- drivers/iio/industrialio-core.c | 27 +++++++ drivers/iio/industrialio-trigger.c | 2 +- drivers/iio/light/apds9960.c | 1 - drivers/iio/magnetometer/rm3100-core.c | 15 +--- drivers/iio/magnetometer/st_magn_core.c | 15 ++-- drivers/iio/pressure/st_pressure_core.c | 8 +-- .../staging/iio/impedance-analyzer/ad5933.c | 1 - include/linux/iio/common/st_sensors.h | 3 + include/linux/iio/iio-opaque.h | 4 ++ include/linux/iio/iio.h | 70 +++++++++++++++---- include/linux/iio/kfifo_buf.h | 5 +- 32 files changed, 151 insertions(+), 131 deletions(-) -- 2.27.0
