You're barking at a wrong tree. /sys/devices/bone_capmgr.9/slots is used to load device tree overlays and has nothing to do with devices on I2C bus. The correct place to write to instantiate a new i2c device is /sys/bus/i2c/devices/i2c-X/new_device (substitute X with bus number to which the chip is connected). The echo command in your case would look like something like this:
echo inv-mpu6050 0x68 > /sys/bus/i2c/devices/i2c-X/new_device j. On Tue, Oct 15, 2013 at 6:02 PM, <[email protected]> wrote: > We are using the Invensense MPU6050 IMU on I2C with Beaglebone Black > (Angstrom 3.8.13). We can use I2C-tools and file I/O thru /dev/i2c but the > read speed is disappointingly slow. We only read the 3x gyros and 3x > accels (each one byte at a time plus the 2 byte temperature reading) and it > takes ~2msecs. My estimate of the I2C bus cycles for a block read > suggests this should take ~160 bus cycles or .38msec on a 400MHz I2C bus. > ****** > > The distribution includes the Invensense driver inv-mpu6050.ko but there > is no indication that reading through /dev/i2c invokes it. This is a > very popular IMU and Invensense widely distributes the driver over many > Linux platforms. The driver source includes “successful installation > will create two directories under /sys/bus/iio/devices” and lists the files > there (aka functions). I can never get these to show up.**** > > I can “insmod > /lib/modules/3.8.13/kernel/drivers/iio/imu/inv_mpu6050/inv-mpu6050.ko” and > “echo inv-mpu6050 0x68 > /sys/class/i2c-adapter/i2c-1/new_device”. This > causes a new directory named 1-0068 to show in > /sys/class/i2c-adapter/i2c-1with entries like name and modalias but no > functions. It never shows in /sys/bus/iio/devices.**** > > What constitutes “successful installation”? **** > > What else is needed to get the inv-mpu6050 to expose functions in > /sys/bus/iio/devices like the driver sources says?**** > > Beaglebone Black uses bone_capemgr for exposing driver functions for many > devices. “echo inv-mpu6050 0x68 > /sys/devices/bone_capmgr.9/slots” > raises the gripe “write error: no such file or directory”. (I can > successfully load the am33xx_pwm driver this way.) Is this because there is > no matching DT fragment in /lib/firmware? Is the inv-mpu6050 driver > supposed to be invoked thru cape manager?**** > Then, most importantly, if I did read and write through the /sys tree > using the Invensense driver would it be faster than /dev/i2c? > Help on sorting this out would be much appreciated. > > -- > For more options, visit http://beagleboard.org/discuss > --- > You received this message because you are subscribed to the Google Groups > "BeagleBoard" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > For more options, visit https://groups.google.com/groups/opt_out. > -- Given a choice between two theories, take the one which is funnier -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/groups/opt_out.
