On Sun, 19 Jan 2025 18:31:57 +0100 Javier Carrasco <javier.carrasco.cruz@xxxxxxxxx> wrote: > This series follows a similar approach as recently used for the veml3235 > by using iio-gts to manage the scale as stated in the ABI. In its > current form, the driver exposes the hardware gain instead of the > multiplier for the raw value to obtain a value in lux. > > Although this driver and the veml3235 have many similarities, there are > two main differences in this series compared to the one used to fix the > other driver: > > - The veml6030 has fractional gains, which are not supported by the > iio-gts helpers. My first attempt was adding support for them, but > that made the whole iio-gts implementation more complex, cumbersome, > and the risk of affecting existing clients was not negligible. > Instead, a x8 factor has been used for the hardware gain to present > the minimum value (x0.125) as x1, keeping linearity. The scales > iio-gts generates are therefore right without any extra conversion, > and they match the values provided in the different datasheets. > > - This driver included a processed value for the ambient light, maybe > because the scale did not follow the ABI and the conversion was not > direct. To avoid breaking userspace, the functionality has been kept, > but of course using the fixed scales. In order to ease the > calculations, iio_gts_get_total_gain() has been exported to avoid > working directly with the scale in NANO, that would require 64-bit > operations. > > To ease the usage of the iio-gts selectors, patches to support regfields > and caching has been included. > > This issue has been present since the original implementation, and it > affects all devices it supports. > > This series has been tested with a veml7700 (same gains as veml6030) and > a veml6035 with positive results. > > Signed-off-by: Javier Carrasco <javier.carrasco.cruz@xxxxxxxxx> Whilst we might consider a backport eventually. This is a huge patch to do that with. Hence I'll take this the slow way for next merge window. For now I've applied patches 1 and 2 in the interest of nibbling away at what we will need to see again ;) Jonathan > --- > Changes in v2: > - Rename SEL_GAIN to indicate they are in MILLI. > - Split first patch (regfields and chaching). > - Use regfield structs in chip struct instead of function pointer. > - Use total gain to derive scale, avoiding 64-bit divisions. > - Link to v1: https://lore.kernel.org/r/20250107-veml6030-scale-v1-0-1281e3ad012c@xxxxxxxxx > > --- > Javier Carrasco (4): > iio: light: veml6030: extend regmap to support regfields > iio: light: veml6030: extend regmap to support caching > iio: gts-helper: export iio_gts_get_total_gain() > iio: light: veml6030: fix scale to conform to ABI > > drivers/iio/industrialio-gts-helper.c | 3 +- > drivers/iio/light/Kconfig | 1 + > drivers/iio/light/veml6030.c | 608 +++++++++++++++++----------------- > include/linux/iio/iio-gts-helper.h | 1 + > 4 files changed, 299 insertions(+), 314 deletions(-) > --- > base-commit: 577a66e2e634f712384c57a98f504c44ea4b47da > change-id: 20241231-veml6030-scale-8142f387e7e6 > > Best regards,
