Re: AM35xx i2c3 issues

[Grygorii Strashko <grygorii.strashko@ti.com>]

Hi Marc,

Could you try these patches first:
https://patchwork.kernel.org/patch/2685541/
http://patchwork.ozlabs.org/patch/252639/

Then try this patch alone:
https://patchwork.kernel.org/patch/2689171/

Also could you provide your .config?  Do you have lm75 (or any other 
hwmon devices) enabled?

-grygorii

On 06/27/2013 12:15 PM, Marc Murphy wrote:
> Hi Michael,
> The bus is correctly terminated with 2.2k pullups on SCL and SDA lines.
>
> Kind Regards
> Marc
>
> ________________________________________
> From: Michael Trimarchi [michael@amarulasolutions.com]
> Sent: 27 June 2013 09:46
> To: Marc Murphy
> Cc: linux-omap@vger.kernel.org
> 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
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