'RE: AM35xx i2c3 issues'

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List:       linux-omap
Subject:    RE: AM35xx i2c3 issues
From:       Marc Murphy <marcmltd () marcm ! co ! uk>
Date:       2013-06-29 20:23:41
Message-ID: F690310232FDDF4AB457E8B3EF90DDE08D2EA18E () MARCM-SBS2011 ! marcmltd ! local
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Hi Grygorii
I tried the three patches but they didn't seem to make a difference. So I put the \
JTAG on and had a look at all the register settings for i2c2 and i2c3 and they are \
all fine.

I thought to switch from the new platform I am bringing up back to the dev platform \
(Technexion twister AM3517) and try and replicate the same connections that I have on \
the target platform and i2c3 is coming up, I can talk to the rtc chip.

I think I will need to get the board back to the hardware guys to get them to check \
the bus for shorts or at least, what I think is the mpu6050 has been fitted \
incorrectly so it's taking the bus down.

Sorry to have raised the non i2c3 channel as an issue, it looks like it's all working \
fine.

Kind Regards
Marc

-----Original Message-----
From: linux-omap-owner@vger.kernel.org [mailto:linux-omap-owner@vger.kernel.org] On \
                Behalf Of Grygorii Strashko
Sent: 27 June 2013 12:13
To: Marc Murphy
Cc: Michael Trimarchi; linux-omap@vger.kernel.org
Subject: Re: AM35xx i2c3 issues

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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