From: Michael Trimarchi <michael@amarulasolutions.com>
To: Marc Murphy <marcmltd@marcm.co.uk>
Cc: "linux-omap@vger.kernel.org" <linux-omap@vger.kernel.org>
Subject: Re: AM35xx i2c3 issues
Date: Thu, 27 Jun 2013 10:46:44 +0200 [thread overview]
Message-ID: <20130627084643.GA12956@panicking> (raw)
In-Reply-To: <F690310232FDDF4AB457E8B3EF90DDE08D2E7A08@MARCM-SBS2011.marcmltd.local>
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
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next prev parent reply other threads:[~2013-06-27 8:46 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <F690310232FDDF4AB457E8B3EF90DDE08D2E797B@MARCM-SBS2011.marcmltd.local>
2013-06-27 8:29 ` AM35xx i2c3 issues Marc Murphy
2013-06-27 8:46 ` Michael Trimarchi [this message]
2013-06-27 9:15 ` Marc Murphy
2013-06-27 11:13 ` Grygorii Strashko
2013-06-29 20:23 ` Marc Murphy
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