[meta-xilinx] Zynq I2C Problem

[MUGRIDGE Robin]

Hi,

Turned out this was a lack of pull-ups on the board!

Thanks,

Robin

From: meta-xilinx-bounces at yoctoproject.org [mailto:meta-xilinx-bounces at yoctoproject.org] On Behalf Of MUGRIDGE Robin
Sent: 10 August 2015 11:30
To: meta-xilinx at yoctoproject.org
Subject: SPOOFED: [meta-xilinx] Zynq I2C Problem

Hi,

I am using linux-xlnx 3.14 (fido) with the Zynq and have an issue with the I2C peripheral using the cdns (r1p10) module.

Our design connects to an external I2C device and we try to identify that device by reading a register from it.  If the device is not connected when the read is performed, the transaction fails with "cdns-i2c e0004000.ps7-i2c: timeout waiting on completion" being output on the console.  After this, all i2c transactions using the i2c0 (e0004000) peripheral fail with "Resource temporarily unavailable".

I've debugged into the cdns module and the call to wait_for_completion_timeout in cdns_i2c_process_msg returns zero (which is fine), but the SR register  has the value 0x00000140 before the cdns_i2c_master_reset call and 0x00000100 afterwards.  This is the bus active (BA) bit which is causing the subsequent transactions to be failed.

How can I get to reset the BA bit?

Incidentally, the cdns_i2c_master_reset method writes to the read only SR register!

I've had a look at the latest code in mainline but can't see that this would be any different.

Thanks,

Robin





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