Hi Michael, The bus is correctly terminated with 2.2k pullups on SCL and SDA lines. Kind Regards Marc ________________________________________ From: Michael Trimarchi [michael@xxxxxxxxxxxxxxxxxxxx] Sent: 27 June 2013 09:46 To: Marc Murphy Cc: linux-omap@xxxxxxxxxxxxxxx Subject: Re: AM35xx i2c3 issues Hi On Thu, Jun 27, 2013 at 08:29:05AM +0000, Marc Murphy wrote: > 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 > Can you check if your bus is correctly pull up on the line? Michael > 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 > -- > To unsubscribe from this list: send the line "unsubscribe linux-omap" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
