So I've been struggling with I2C. Somebody on this list gave me the tip to do:
echo BB-I2C1 > /sys/devices/bone_capemgr.??**??/slots which enables the third I2C bus and my device then was visible via i2cdetect -y -r 1 on pins P9_19 and P9_20. Although, after doing that, you'll have an i2c1 and a i2c2 bus, so might want to check both. But, I'm not quite sure why this works :) In my case, I don't think there is device tree entry for the device I'm using, so I was planning on interacting with it over raw I2C. Hope this helps, Josh On Thursday, October 31, 2013 2:32:46 PM UTC-6, Jason Kridner wrote: > > On Tue, Oct 29, 2013 at 2:19 PM, Jason Kridner > <jkri...@beagleboard.org<javascript:>> > wrote: > > > > On Thu, Oct 17, 2013 at 6:12 PM, <clarkbr...@gmail.com <javascript:>> > wrote: > > > AIW: > > > I went back thru the adafruit library and didn't find anything > specific on > > > I2C, although it is listed as a topic. I have been looking at their > github > > > adafruit-beaglebone-io-python library. I also found and looked thru > PyBBIO. > > > Even tho I'm not using Python, I can see the access mechanisms that > they > > > use. > > > I can use the MPU6050 device ok enough just reading via > /dev/i2c/i2c-x, but > > > that is too slow. > > > I'm trying to figure out how to invoke and use the inv-mpu6050 driver > and > > > adafruit doesn't use that. > > > Thx -- Clark > > > > > > On Thursday, October 17, 2013 9:47:44 AM UTC-7, AIW wrote: > > >> > > >> Some good info on I2C tools at http://www.acmesystems.it/i2c. > > >> > > >> Python and the adafruit BBIO I2C library makes it very easy to use > I2C on > > >> Beaglebone Black as well. Python import smbus is fairly easy to use > too. > > >> Some examples of use is available in the code I provide for my radio > project > > >> here....www.aiwindustries.com. > > >> > > >> Not trying to sell the product, but I know that the I2C function was > > >> giving me some issues so I'm just trying to help the community. > Python code > > >> is available to download and look at usage so feel free. > > >> > > >> On Tuesday, October 15, 2013 5:02:59 PM UTC-5, > > >> clarkbr...@gmail.comwrote: > > >>> > > >>> 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. > > > > You are running at 400kHz, not 400MHz, right? I2C doesn't do 400MHz. > > > > >>> > > >>> 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. > > > > I don't have an MPU6050, but I just ordered a couple on express > > overnight from Sparkfun. > > I bought https://www.sparkfun.com/products/11028 and played with it > briefly before being distracted and again today, but I don't > understand why I'm not able to get it to reply to me. > > I have the following connections: > VCC: P9_4 (VDD_3V3) > GNC: P9_1 (GND) > INT: P9_11 (GPIO) > FSYNC: - > SCL: P9_19 (I2C2_SCL) > SDA: P9_20 (I2C2_SDA) > VIO: P9_3 (VDD_3V3) > CLK: - > ASCL: - > ASDA: - > > I then perform: > > root@beaglebone:~# i2cdetect -y -r 1 > 0 1 2 3 4 5 6 7 8 9 a b c d e f > 00: -- -- -- -- -- -- -- -- -- -- -- -- -- > 10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- > 20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- > 30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- > 40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- > 50: -- -- -- -- UU UU UU UU -- -- -- -- -- -- -- -- > 60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- > 70: -- -- -- -- -- -- -- -- > > Very confused why it doesn't show up. > > Since you have it responding to you, how do you have it wired? > > > > > Here's the behavior I'm seeing without the board connected: > > > > root@beaglebone:/lib/modules/3.8.13/kernel/drivers/iio/imu/inv_mpu6050# > ls > > inv-mpu6050.ko > > root@beaglebone:/lib/modules/3.8.13/kernel/drivers/iio/imu/inv_mpu6050# > > dmesg | tail -1 > > [ 2992.799594] i2c i2c-1: new_device: Instantiated device inv-mpu6050 at > 0x68 > > root@beaglebone:/lib/modules/3.8.13/kernel/drivers/iio/imu/inv_mpu6050# > lsmod > > Module Size Used by > > ip_tables 8294 0 > > x_tables 15072 1 ip_tables > > g_multi 55905 2 > > libcomposite 15228 1 g_multi > > rfcomm 25106 0 > > ircomm_tty 14503 0 > > ircomm 8846 1 ircomm_tty > > irda 89974 2 ircomm_tty,ircomm > > ipv6 229989 14 > > hidp 10112 0 > > bluetooth 146100 4 hidp,rfcomm > > rfkill 16510 2 bluetooth > > autofs4 17432 2 > > > > I looked for the installed device: > > > > root@beaglebone:/lib/modules/3.8.13/kernel/drivers/iio/imu/inv_mpu6050# > > cat /sys/bus/iio/devices/iio*/name > > tiadc > > root@beaglebone:/lib/modules/3.8.13/kernel/drivers/iio/imu/inv_mpu6050# > > ls /sys/bus/iio/devices/iio* -d > > /sys/bus/iio/devices/iio:device0 > > > > It is clearly missing per the documentation > > ( > https://www.kernel.org/doc/Documentation/ABI/testing/sysfs-bus-iio-mpu6050) > > > that says there should be a sysfs entry there. > > > > Just in case I could get it to show up, I did try manually doing a > modprobe. > > > > root@beaglebone:/lib/modules/3.8.13/kernel/drivers/iio/imu/inv_mpu6050# > > modprobe inv-mpu6050 > > root@beaglebone:/lib/modules/3.8.13/kernel/drivers/iio/imu/inv_mpu6050# > lsmod > > Module Size Used by > > inv_mpu6050 7190 0 > > ip_tables 8294 0 > > x_tables 15072 1 ip_tables > > g_multi 55905 2 > > libcomposite 15228 1 g_multi > > rfcomm 25106 0 > > ircomm_tty 14503 0 > > ircomm 8846 1 ircomm_tty > > irda 89974 2 ircomm_tty,ircomm > > ipv6 229989 14 > > hidp 10112 0 > > bluetooth 146100 4 hidp,rfcomm > > rfkill 16510 2 bluetooth > > autofs4 17432 2 > > root@beaglebone:/lib/modules/3.8.13/kernel/drivers/iio/imu/inv_mpu6050# > > ls /sys/bus/iio/devices/iio* -d > > /sys/bus/iio/devices/iio:device0 > > > > Of course, this all makes perfect sense since the driver should exit > > upon failing the 'probe': > > > https://github.com/beagleboard/linux/blob/3.8/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c#L658 > > > > > I'd have to look up how to turn on more debugging statements. I tried > > the hints at http://elinux.org/Debugging_by_printing, but I'm > > surprised the 'dmesg' log didn't show any extra errors. > > > > > > >>> > > >>> 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? > > > > I don't think anything else should be required. To build the kernel > > properly, there are a few things that need to be enabled > > ( > https://github.com/beagleboard/linux/blob/3.8/drivers/iio/imu/inv_mpu6050/Kconfig): > > > > > > INV_MPU6050_IIO, I2C, SYSFS, IIO_BUFFER, IIO_TRIGGERED_BUFFER > > > > And they are all there: > > https://github.com/beagleboard/kernel/blob/3.8/configs/beaglebone#L3676 > > > > >>> > > >>> 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? > > > > Yes. > > > > >>> Is the inv-mpu6050 driver supposed to be > > >>> invoked thru cape manager? > > > > No, because the I2C bus software provides another mechanism. I believe > > you could create a DT fragment, but I think it is pointless. > > > > >>> > > >>> 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. > > > > Yes, because the driver running in kernel mode is going to be higher > > performance than your pokes from userspace. > > > > > > > > -- > > > 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 beagleboard...@googlegroups.com <javascript:>. > > > For more options, visit https://groups.google.com/groups/opt_out. > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. 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