On Fri, Feb 22, 2019 at 10:25:19AM +0100, Ludovic Desroches wrote:
> [Ludovic Desroches: see Changes section]
>
> Based on the discussion we had on the i2c-linux list [1], I wrote a patch for
> AT91 hardware and tried to fulfill the Linux I2C slave interface description
> [2] as good as possible. This enables aforementioned hardware to act as an I2C
> slave that can be accessed by a remote I2C master.
>
> I have tested this patchset successfully on an ATSAMA5D27.
>
> ^ 3.3V ^ 3.3V
> +-----------------------+ | | +-----------------------+
> | Slave: ATSAMA5D27 | +-+ +-+ | Master: ATSAMA5D35 |
> | with i2c-slave-eeprom | | | 100k | | 100k | with i2cset |
> +-------------------+-+-+ +-+ +-+ +-+-+-------------------+
> | | | | | |
> | +------+---------|---(SDA)---+ |
> +------------------+---(SCL)-----+
>
> Schematic: Connection of slave and master with 100kOhm pullup resistors.
>
> On the master the following BASH script has been used to stress the slave.
>
> root@emblinux:~# cat ./stress.sh
> #!/bin/bash
Not everybody has bash in their environments. See below, how easily to switch
to regular shell.
#!/bin/sh
> I=0
> while true
> do
> if i2cset -y -r 1 0x64 0 $I w | grep mismatch
> then
> echo "$(date): Error in transmission ${I}"
> fi
> ((I++))
I=$(($I+1))
> if [ $I -eq 65536 ]
> then
> I=0
> echo "$(date): Sent 65536 transmissions"
> fi
This one can be optimized to
for I in $(seq 65536); do
...
done
> done
>
> After running the script for some time I had the following output. To me this
> looks promising :)
>
> root@emblinux:~# ./stress.sh
> Thu Nov 9 13:58:45 CTE 2017: Sent 65536 transmissions
> Thu Nov 9 14:35:20 CTE 2017: Sent 65536 transmissions
> Thu Nov 9 15:12:11 CTE 2017: Sent 65536 transmissions
> Thu Nov 9 15:49:04 CTE 2017: Sent 65536 transmissions
> Thu Nov 9 16:26:00 CTE 2017: Sent 65536 transmissions
> Thu Nov 9 17:03:07 UTC 2017: Sent 65536 transmissions
> Thu Nov 9 17:40:15 UTC 2017: Sent 65536 transmissions
>
> If you have some hardware with an at91-i2c interface included at hand, I really
> would appreciate if you can run the test script on your hardware and test this
> driver.
> Thu Nov 9 17:40:15 UTC 2017: Sent 65536 transmissions
>
> If you have some hardware with an at91-i2c interface included at hand, I really
> would appreciate if you can run the test script on your hardware and test this
> driver.
--
With Best Regards,
Andy Shevchenko
