Hello Grygorii/All,
I have been trying to address an issue I am having with 3.6rc6 kernel and even with the latest 3.9 and trying to use i2c3 channel on an AM3517.
I see that there has been some work done on the OMAP4 and issues with i2c which looks like the controller being suspended during boot.
I would like to know how I can enable the debug so I can see the messages for warning and debug and whether anyone has tested i2c3 channel on an AM3517 ?
I find the problem a little confusing as the system initializes the interfaces 1-3
[ 0.168182] omap_i2c omap_i2c.1: bus 1 rev1.3.12 at 400 kHz
[ 0.169830] VDCDC1: 1200 <--> 1600 mV at 1200 mV normal
[ 0.169830] VDCDC1: Voltage range but no REGULATOR_CHANGE_VOLTAGE
[ 0.170684] VDCDC2: 3300 mV normal
[ 0.171264] VDCDC3: 1800 mV normal
[ 0.171905] LDO1: 1800 mV normal
[ 0.172729] LDO2: 3300 mV normal
[ 0.174102] omap_i2c omap_i2c.2: bus 2 rev1.3.12 at 400 kHz
[ 0.187530] omap_i2c omap_i2c.3: bus 3 rev1.3.12 at 400 kHz
But when it comes to probe the i2c3 interface for the mpu6050 that is connected it fails
[ 3.896606] omap_i2c omap_i2c.3: timeout waiting for bus ready
[ 3.902832] inv-mpu6050: probe of 3-0068 failed with error -110
If I move the mpu6050 onto the i2c2 channel it’s OK so its not an issue with the core omap_i2c.
I also have a scope connected to the scl line and see no activity. I have proved to myself that the pin is connected and working by configuring as a GPIO output and toggling 0/1/0 and I can see the output changing on the scope.
The mux is configured correctly from what I can see using debugfs
# cat /sys/kernel/debug/omap_mux/i2c3_scl
name: i2c3_scl.i2c3_scl (0x480021c2/0x192 = 0x0100), b af14, t NA
mode: OMAP_PIN_INPUT | OMAP_MUX_MODE0
signals: i2c3_scl | NA | NA | NA | gpio_184 | NA | NA | safe_mode
# cat /sys/kernel/debug/omap_mux/i2c3_sda
name: i2c3_sda.i2c3_sda (0x480021c4/0x194 = 0x0100), b ag14, t NA
mode: OMAP_PIN_INPUT | OMAP_MUX_MODE0
signals: i2c3_sda | NA | NA | NA | gpio_185 | NA | NA | safe_mode
If I probe with i2cdetect for all 3 buses there is only an issue with i2c3
# i2cdetect -r 1
WARNING! This program can confuse your I2C bus, cause data loss and worse!
I will probe file /dev/i2c-1 using read byte commands.
I will probe address range 0x03-0x77.
Continue? [Y/n]
0 1 2 3 4 5 6 7 8 9 a b c d e f
00: -- -- -- -- -- -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- UU -- -- -- -- -- -- --
50: 50 -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --
# i2cdetect -r 2
WARNING! This program can confuse your I2C bus, cause data loss and worse!
I will probe file /dev/i2c-2 using read byte commands.
I will probe address range 0x03-0x77.
Continue? [Y/n]
0 1 2 3 4 5 6 7 8 9 a b c d e f
00: -- -- -- -- -- -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --
# i2cdetect -r 3
WARNING! This program can confuse your I2C bus, cause data loss and worse!
I will probe file /dev/i2c-3 using read byte commands.
I will probe address range 0x03-0x77.
Continue? [Y/n]
0 1 2 3 4 5 6 7 8 9 a b c d e f
00: [ 837.943481] omap_i2c omap_i2c.3: timeout waiting for bus ready
-- [ 838.958984] omap_i2c omap_i2c.3: timeout waiting for bus ready
-- [ 839.974731] omap_i2c omap_i2c.3: timeout waiting for bus ready
Any pointers/help appreciated as I have the accelerometer and RTC chip connected on i2c3 but cannot get anything working.
Kind Regards
Marc
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