user/sven/linux.git/include/linux/iio/common, branch v4.9.53

iio: accel: st_accel: fix LIS3LV02 reading and scaling

2017-01-12T10:39:21Z

commit 65e4345c8ef8811bbb4860fe5f2df10646b7f2e1 upstream. The LIS3LV02 has a special bit that need to be set to get the read values left aligned. Before this patch we get gibberish like this: iio_generic_buffer -a -c10 -n lis3lv02dl_accel (...) 0.000000 -0.010042 -0.642688 19155832931907 0.000000 -0.010042 -0.642688 19155858751073 Which is because we read a raw value for 1g as 64 which is the nominal 1024 for 1g shifted 4 bits to the left by being right-aligned rather than left aligned. Since all other sensors are left aligned, add some code to set the special DAS (data alignment setting) bit to 1 so that the right value is now read like this: iio_generic_buffer -a -c10 -n lis3lv02dl_accel (...) 0.000000 -0.147095 -10.120135 24761614364956 -0.029419 -0.176514 -10.120135 24761631624540 The scaling was weird as well: we have a gain of 1000 for 1g and 3000 for 6g. I don't even remember how I came up with the old values but they are wrong. Fixes: 3acddf74f807 ("iio: st-sensors: add support for lis3lv02d accelerometer") Cc: Lorenzo Bianconi Cc: Giuseppe Barba Cc: Denis Ciocca Signed-off-by: Linus Walleij Signed-off-by: Jonathan Cameron Signed-off-by: Greg Kroah-Hartman

iio: st_sensors: harden interrupt handling

2016-07-02T19:40:15Z

Leonard Crestez observed the following phenomenon: when using hard interrupt triggers (the DRDY line coming out of an ST sensor) sometimes a new value would arrive while reading the previous value, due to latencies in the system. We discovered that the ST hardware as far as can be observed is designed for level interrupts: the DRDY line will be held asserted as long as there are new values coming. The interrupt handler should be re-entered until we're out of values to handle from the sensor. If interrupts were handled as occurring on the edges (usually low-to-high) new values could appear and the line be held asserted after that, and these values would be missed, the interrupt handler would also lock up as new data was available, but as no new edges occurs on the DRDY signal, nothing happens: the edge detector only detects edges. To counter this, do the following: - Accept interrupt lines to be flagged as level interrupts using IRQF_TRIGGER_HIGH and IRQF_TRIGGER_LOW. If the line is marked like this (in the device tree node or ACPI table or similar) it will be utilized as a level IRQ. We mark the line with IRQF_ONESHOT and mask the IRQ while processing a sample, then the top half will be entered again if new values are available. - If we are flagged as using edge interrupts with IRQF_TRIGGER_RISING or IRQF_TRIGGER_FALLING: remove IRQF_ONESHOT so that the interrupt line is not masked while running the thread part of the interrupt. This way we will never miss an interrupt, then introduce a loop that polls the data ready registers repeatedly until no new samples are available, then exit the interrupt handler. This way we know no new values are available when the interrupt handler exits and new (edge) interrupts will be triggered when data arrives. Take some extra care to update the timestamp in the poll loop if this happens. The timestamp will not be 100% perfect, but it will at least be closer to the actual events. Usually the extra poll loop will handle the new samples, but once in a blue moon, we get a new IRQ while exiting the loop, before returning from the thread IRQ bottom half with IRQ_HANDLED. On these rare occasions, the removal of IRQF_ONESHOT means the interrupt will immediately fire again. - If no interrupt type is indicated from the DT/ACPI, choose IRQF_TRIGGER_RISING as default, as this is necessary for legacy boards. Tested successfully on the LIS331DL and L3G4200D by setting sampling frequency to 400Hz/800Hz and stressing the system: extra reads in the threaded interrupt handler occurs. Cc: Giuseppe Barba Cc: Denis Ciocca Tested-by: Crestez Dan Leonard Reported-by: Crestez Dan Leonard Signed-off-by: Linus Walleij Signed-off-by: Jonathan Cameron

Merge 4.7-rc4 into staging-next

2016-06-20T15:25:44Z

We want the fixes in here, and we can resolve a merge issue in drivers/iio/industrialio-trigger.c Signed-off-by: Greg Kroah-Hartman

iio: st_sensors: switch to a threaded interrupt

2016-05-29T19:21:41Z

commit 98ad8b41f58dff6b30713d7f09ae3834b8df7ded ("iio: st_sensors: verify interrupt event to status") caused a regression when reading ST sensors from a HRTimer trigger rather than the intrinsic interrupts: the HRTimer may trigger faster than the sensor provides new values, and as the check against new values available as a cause of the interrupt trigger was done in the poll function, this would bail out of the HRTimer interrupt with IRQ_NONE. So clearly we need to only check the new values available from the proper interrupt handler and not from the poll function, which should rather just read the raw values from the registers, put them into the buffer and be happy. To achieve this: switch the ST Sensors over to using a true threaded interrupt handler. In the interrupt thread, check if new values are available, else yield to the (potential) next device on the same interrupt line to check the registers. If the interrupt was ours, proceed to poll the values. Instead of relying on iio_trigger_generic_data_rdy_poll() as a top half to wake up the thread that polls the sensor for new data, have the thread call iio_trigger_poll_chained() after determining that is is the proper source of the interrupt. This is modelled on drivers/iio/accel/mma8452.c which is already using a properly threaded interrupt handler. In order to get the same precision in timestamps as previously, where samples would be timestamped in the poll function pf->timestamp when calling iio_trigger_generic_data_rdy_poll() we introduce a local timestamp in the sensor data, set it in the top half (fastpath) of the interrupt handler and provide that to the core when calling iio_push_to_buffers_with_timestamp(). Additionally: if the active scanmask is not set for the sensor no IRQs should be enabled and we need to bail out with IRQ_NONE. This can happen if spurious IRQs fire when installing the threaded interrupt handler. Tested with hard interrupt triggers on LIS331DL, then also tested with hrtimers on the same sensor by creating a 75Hz HRTimer and using it to poll the sensor. Signed-off-by: Linus Walleij Cc: Giuseppe Barba Cc: Denis Ciocca Reported-by: Crestez Dan Leonard Tested-by: Crestez Dan Leonard Tested-by: Jonathan Cameron Fixes: 97865fe41322 ("iio: st_sensors: verify interrupt event to status") Signed-off-by: Jonathan Cameron

iio:st_sensors: fix power regulator usage

2016-05-29T15:08:10Z

Ensure failure to enable power regulators is properly handled. Signed-off-by: Gregor Boirie Signed-off-by: Jonathan Cameron

iio:st_sensors: unexport st_sensors_get_buffer_element

2016-05-29T15:00:56Z

Remove st_sensors_get_buffer_element symbol export since not explicitly used outside of st_sensors driver. Signed-off-by: Gregor Boirie Signed-off-by: Jonathan Cameron

iio: st_sensors: support open drain mode

2016-04-19T18:58:13Z

Some types of ST Sensors can be connected to the same IRQ line as other peripherals using open drain. Add a device tree binding and a sensor data property to flip the right bit in the interrupt control register to enable open drain mode on the INT line. If the line is set to be open drain, also tag on IRQF_SHARED to the IRQ flags when requesting the interrupt, as the whole point of using open drain interrupt lines is to share them with more than one peripheral (wire-or). Cc: devicetree@vger.kernel.org Cc: Giuseppe Barba Cc: Denis Ciocca Acked-by: Rob Herring Signed-off-by: Linus Walleij Signed-off-by: Jonathan Cameron

iio: st_sensors: verify interrupt event to status

2016-04-19T18:58:12Z

This makes all ST sensor drivers check that they actually have new data available for the requested channel(s) before claiming an IRQ, by reading the status register (which is conveniently the same for all ST sensors) and check that the channel has new data before proceeding to read it and fill the buffer. This way sensors can share an interrupt line: it can be flaged as shared and then the sensor that did not fire will return NO_IRQ, and the sensor that fired will handle the IRQ and return IRQ_HANDLED. Cc: Giuseppe Barba Cc: Denis Ciocca Signed-off-by: Linus Walleij Signed-off-by: Jonathan Cameron

iio: st_sensors: support active-low interrupts

2016-01-10T12:35:32Z

Most ST MEMS Sensors that support interrupts can also handle sending an active low interrupt, i.e. going from high to low on data ready (or other interrupt) and thus triggering on a falling edge to the interrupt controller. Set up logic to inspect the interrupt line we get for a sensor: if it is triggering on rising edge, leave everything alone, but if it triggers on falling edges, set up active low, and if unsupported configurations appear: warn with errors and reconfigure the interrupt to a rising edge, which all interrupt generating sensors support. Create a local header for st_sensors_core.h to share functions between the sensor core and the trigger setup code. Cc: Giuseppe Barba Cc: Denis Ciocca Signed-off-by: Linus Walleij Signed-off-by: Jonathan Cameron

iio: st_sensors: add debugfs register read hook

2015-08-16T09:51:25Z

This adds a debugfs hook to read/write registers in the ST sensors using debugfs. Proved to be awesome help when trying to debug why IRQs do not arrive. Signed-off-by: Linus Walleij Acked-by: Denis Ciocca Signed-off-by: Jonathan Cameron