Hi to everyone,
This question is a bit long, but please bear with me for a moment, as
we need your help to understand if we are doing something wrong (first
time IIO usage on our side).
We are working on project with SAMA5D3 board and accelerometer
(lis331dlh) sensor and linux 3.17-rc5. We successfully connected
lis331dlh to board via SPI interface, and we are able to read sensor
through spidev and also through IIO interface by reading raw values.
But there is a problem with IIO buffer, as we are not able to get any
data through buffer.
Our understanding is that we should define interrupt which will be
triggered outside (by sensor data-ready-int output), and this
interrupt will trigger IIO to read data and store it to buffer.
Sensor <data ready> output is connected to Port D, pin 21 of CPU, and
device tree looks like:
spi1: spi@f8008000 {
cs-gpios = <&pioC 25 0>;
status = "okay";
lis331dlh@0 {
compatible = "st,lis331dlh-accel";
spi-max-frequency = <10000000>;
reg = <0>;
interrupt-parent = <&pioD>;
interrupts = <21 IRQ_TYPE_LEVEL_HIGH>;
st,drdy-int-pin = <1>;
};
};
and on boot up we got these messages:
st-accel-spi spi32765.0: st_sensors_of_spi_probe() - lis331dlh.
iio iio:device0: st_sensors_check_device_support() - lis331dlh.
iio iio:device0: st_sensors_init_sensor().
iio iio:device0: st_sensors_set_drdy_int_pin() - drdy_int_pin=1.
iio iio:device0: st_accel_allocate_ring()
iio iio:device0: st_accel_common_probe() - irq: 172.
iio iio:device0: registered accelerometer lis331dlh
As you can see, accelerometer is succesfully registered, and we are
able to read raw data with:
$ cat /sys/bus/iio/devices/iio:device0/in_accel_x_raw
this is how our directory looks like:
$ ls -al /sys/bus/iio/devices/
lrwxrwxrwx 1 root root 0 Jan 1 00:17 iio:device0
-> ../../../devices/ahb/ahb:apb/f8008000.spi/spi_master/spi32765/spi32765.0/iio:device0
lrwxrwxrwx 1 root root 0 Jan 1 00:17 trigger0 ->
../../../devices/ahb/ahb:apb/f8008000.spi/spi_master/spi32765/spi32765.0/trigger0
So trigger is also registred with name lis331dlh-trigger.
dmsg line:
...
iio iio:device0: st_accel_common_probe() - irq: 172.
...
indicates that irq 172 (which is IRQ for Port D, pin 21) is registered
(which is also checked in /proc/irq).
So, with all this set, we are not successful to get data from buffer.
Our first guess is to use generic_buffer.c, which we successfully
tried on internal ADC, but there is no data in buffer.
Steps we are using are:
Enable channel in_accel_x_en in iio:device0/scan_elements
Write <lis331dlh-trigger> in iio:device0/trigger/current_trigger
Write length of 16 in iio:device0/buffer/length
Write 1 in iio:device0/buffer/enable
That should be enough to get data into buffer by driver and than to
read it from buffer. Is that true? Did we missed something.
>From HW point of view, we could see transition on interrupt pin when
we enable buffer, but no reading of data.
Our understanding is that function <irqreturn_t
st_sensors_trigger_handler(int irq, void *p)> from file
linux/drivers/iio/common/st_sensors/st_sensors_buffer.c should be
called when interrupt is generated. Is this assumption correct? In our
case it's never called.
Thanks in advance
Branko
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