We see several performance issues reading individual axis, when raw read is the only option. Since most of the time user space reads x, y and z, one after other, this results in three sysfs reads, and based on chipset we have to power up or set up measurement mode and wait for response. For example reading x,y and z takes 160ms for ak8975, it is true for other too. But reading together takes only 80ms. IIO types already defined a modifier for X_AND_Y_AND_Z, which is used by one driver to send event code. This modifier has no value assigned so (null) appears in sysfs. If this is not correct then we may need another modifier. Since we have now raw_read with capability to read multiple values, we can use this callback to return values to iio core. Srinivas Pandruvada (2): iio: core: add xyz modifier value iio: magnetometer: ak8975: Improve performance of raw reads drivers/iio/industrialio-core.c | 1 + drivers/iio/magnetometer/ak8975.c | 58 ++++++++++++++++++++++++++------------- 2 files changed, 40 insertions(+), 19 deletions(-) -- 1.8.3.2 -- 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
