Regression: at24 eeprom writing times out on sama5d3

Peter Rosin peda at axentia.se
Fri Jun 10 13:51:08 PDT 2022 

Hi!

2022-06-10 at 09:35, Codrin.Ciubotariu at microchip.com wrote:
> On 09.06.2022 17:28, Peter Rosin wrote:
>> Hi!
> 
> Hi Peter,
> 
>>
>> I have not actually bisected this issue but reverting the effects of
>> patch a4bd8da893a3 ("ARM: dts: at91: sama5d3: add i2c gpio pinctrl")
>> makes the problem go away.
>>
>> I.e. I need something like this in my dts
>>
>> &i2c2 {
>>          status = "okay";
>>
>>          pinctrl-names = "default";
>>          /delete-property/ pinctrl-1;
>>          /delete-property/ sda-gpios;
>>          /delete-property/ scl-gpios;
>>
>>          eeprom at 50 {
>>                  compatible = "st,24c64", "atmel,24c64";
>>                  reg = <0x50>;
>>                  wp-gpios = <&filter_gpio 7 GPIO_ACTIVE_HIGH>;
>>          };
>> };
>>
>> for multi-page eeprom writes to not time out (a page is 32 bytes on this
>> eeprom).
>>
>> For reference, the current defaults for this SoC/I2C-bus, that I modify,
>> are:
>>
>>          pinctrl-names = "default", "gpio";
>>          pinctrl-0 = <&pinctrl_i2c2>;
>>          pinctrl-1 = <&pinctrl_i2c2_gpio>;
>>          sda-gpios = <&pioA 18 GPIO_ACTIVE_HIGH>;
>>          scl-gpios = <&pioA 19 (GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN)>;
>>
>> I suspect that the underlying reason is that the bus recovery takes
>> too long and that the at24 eeprom driver gives up prematurely. I doubt
>> that this is chip specific, but I don't know that.
>>
>> I can work around the issue in user space with by writing in 4 byte
>> chunks, like so
>>
>> dd if=source.file of=/sys/bus/i2c/devices/2-0050/eeprom obs=4
>>
>> but that is really ugly and gets slow too, about 20 seconds to program
>> the full 8kB eeprom. With the above in my dts it takes a second or
>> so (a bit more with dynamic debug active).
>>
>>
>> If I run
>>
>> dd if=source.file of=/sys/bus/i2c/devices/2-0050/eeprom
>>
>> with a source.file of 8kB and the upstream dts properties in place, I can
>> collect the following debug output from at24, i2c-core and i2c-at91:
>>
>> Jun  9 15:56:34 me20 kernel: i2c i2c-2: at91_xfer: processing 1 messages:
>> Jun  9 15:56:34 me20 kernel: at91_i2c f801c000.i2c: transfer: write 34 bytes.
>> Jun  9 15:56:34 me20 kernel: at91_i2c f801c000.i2c: transfer complete
>> Jun  9 15:56:34 me20 kernel: at24 2-0050: write 32 at 0 --> 0 (-23170)
>> Jun  9 15:56:34 me20 kernel: i2c i2c-2: at91_xfer: processing 1 messages:
>> Jun  9 15:56:34 me20 kernel: at91_i2c f801c000.i2c: transfer: write 34 bytes.
>> Jun  9 15:56:34 me20 kernel: at91_i2c f801c000.i2c: received nack
>> Jun  9 15:56:34 me20 kernel: i2c i2c-2: Trying i2c bus recovery
>> Jun  9 15:56:34 me20 kernel: at24 2-0050: write 32 at 32 --> -121 (-23169)
>> Jun  9 15:56:34 me20 kernel: i2c i2c-2: at91_xfer: processing 1 messages:
>> Jun  9 15:56:34 me20 kernel: at91_i2c f801c000.i2c: transfer: write 34 bytes.
>> Jun  9 15:56:34 me20 kernel: at91_i2c f801c000.i2c: transfer complete
>> Jun  9 15:56:34 me20 kernel: at24 2-0050: write 32 at 32 --> 0 (-23168)
>> Jun  9 15:56:34 me20 kernel: i2c i2c-2: at91_xfer: processing 1 messages:
>> Jun  9 15:56:34 me20 kernel: at91_i2c f801c000.i2c: transfer: write 34 bytes.
>> Jun  9 15:56:34 me20 kernel: at91_i2c f801c000.i2c: received nack
>> Jun  9 15:56:34 me20 kernel: i2c i2c-2: Trying i2c bus recovery
>> Jun  9 15:56:34 me20 kernel: at24 2-0050: write 32 at 64 --> -121 (-23168)
>> Jun  9 15:56:34 me20 kernel: i2c i2c-2: at91_xfer: processing 1 messages:
>> Jun  9 15:56:34 me20 kernel: at91_i2c f801c000.i2c: transfer: write 34 bytes.
>> Jun  9 15:56:34 me20 kernel: at91_i2c f801c000.i2c: transfer complete
>> Jun  9 15:56:34 me20 kernel: at24 2-0050: write 32 at 64 --> 0 (-23167)
>> Jun  9 15:56:34 me20 kernel: i2c i2c-2: at91_xfer: processing 1 messages:
>> Jun  9 15:56:34 me20 kernel: at91_i2c f801c000.i2c: transfer: write 34 bytes.
>> Jun  9 15:56:34 me20 kernel: at91_i2c f801c000.i2c: received nack
>> Jun  9 15:56:34 me20 kernel: i2c i2c-2: Trying i2c bus recovery
>> Jun  9 15:56:34 me20 kernel: at24 2-0050: write 32 at 96 --> -121 (-23167)
>> Jun  9 15:56:34 me20 kernel: i2c i2c-2: at91_xfer: processing 1 messages:
>> Jun  9 15:56:34 me20 kernel: at91_i2c f801c000.i2c: transfer: write 34 bytes.
>> Jun  9 15:56:34 me20 kernel: at91_i2c f801c000.i2c: controller timed out
>> Jun  9 15:56:34 me20 kernel: i2c i2c-2: Trying i2c bus recovery
>> Jun  9 15:56:34 me20 kernel: at24 2-0050: write 32 at 96 --> -110 (-23155)
>> Jun  9 15:56:34 me20 kernel: i2c i2c-2: at91_xfer: processing 1 messages:
>> Jun  9 15:56:34 me20 kernel: at91_i2c f801c000.i2c: transfer: write 34 bytes.
>> Jun  9 15:56:34 me20 kernel: at91_i2c f801c000.i2c: controller timed out
>> Jun  9 15:56:34 me20 kernel: i2c i2c-2: Trying i2c bus recovery
>> Jun  9 15:56:34 me20 kernel: at24 2-0050: write 32 at 96 --> -110 (-23143)
>>
>> And then there is no more action. I.e. only a couple of 32 byte pages
>> are written.
>>
>> With the above mentioned dts override in place I instead get this, which is
>> a lot more sensible:
>>
>> Jun  9 15:48:53 me20 kernel: i2c i2c-2: at91_xfer: processing 1 messages:
>> Jun  9 15:48:53 me20 kernel: at91_i2c f801c000.i2c: transfer: write 34 bytes.
>> Jun  9 15:48:53 me20 kernel: at91_i2c f801c000.i2c: transfer complete
>> Jun  9 15:48:53 me20 kernel: at24 2-0050: write 32 at 0 --> 0 (753629)
>> Jun  9 15:48:53 me20 kernel: i2c i2c-2: at91_xfer: processing 1 messages:
>> Jun  9 15:48:53 me20 kernel: at91_i2c f801c000.i2c: transfer: write 34 bytes.
>> Jun  9 15:48:53 me20 kernel: at91_i2c f801c000.i2c: received nack
>> Jun  9 15:48:53 me20 kernel: at24 2-0050: write 32 at 32 --> -121 (753629)
>> Jun  9 15:48:53 me20 kernel: i2c i2c-2: at91_xfer: processing 1 messages:
>> Jun  9 15:48:53 me20 kernel: at91_i2c f801c000.i2c: transfer: write 34 bytes.
>> Jun  9 15:48:53 me20 kernel: at91_i2c f801c000.i2c: transfer complete
>> Jun  9 15:48:53 me20 kernel: at24 2-0050: write 32 at 32 --> 0 (753630)
>> Jun  9 15:48:53 me20 kernel: i2c i2c-2: at91_xfer: processing 1 messages:
>> Jun  9 15:48:53 me20 kernel: at91_i2c f801c000.i2c: transfer: write 34 bytes.
>> Jun  9 15:48:53 me20 kernel: at91_i2c f801c000.i2c: received nack
>> Jun  9 15:48:53 me20 kernel: at24 2-0050: write 32 at 64 --> -121 (753630)
>> Jun  9 15:48:53 me20 kernel: i2c i2c-2: at91_xfer: processing 1 messages:
>> Jun  9 15:48:53 me20 kernel: at91_i2c f801c000.i2c: transfer: write 34 bytes.
>> Jun  9 15:48:53 me20 kernel: at91_i2c f801c000.i2c: transfer complete
>> Jun  9 15:48:53 me20 kernel: at24 2-0050: write 32 at 64 --> 0 (753631)
>> Jun  9 15:48:53 me20 kernel: i2c i2c-2: at91_xfer: processing 1 messages:
>> Jun  9 15:48:53 me20 kernel: at91_i2c f801c000.i2c: transfer: write 34 bytes.
>> Jun  9 15:48:53 me20 kernel: at91_i2c f801c000.i2c: received nack
>> Jun  9 15:48:53 me20 kernel: at24 2-0050: write 32 at 96 --> -121 (753631)
>> Jun  9 15:48:53 me20 kernel: i2c i2c-2: at91_xfer: processing 1 messages:
>> Jun  9 15:48:53 me20 kernel: at91_i2c f801c000.i2c: transfer: write 34 bytes.
>> Jun  9 15:48:53 me20 kernel: at91_i2c f801c000.i2c: transfer complete
>> Jun  9 15:48:53 me20 kernel: at24 2-0050: write 32 at 96 --> 0 (753632)
>> Jun  9 15:48:53 me20 kernel: i2c i2c-2: at91_xfer: processing 1 messages:
>> Jun  9 15:48:53 me20 kernel: at91_i2c f801c000.i2c: transfer: write 34 bytes.
>> Jun  9 15:48:53 me20 kernel: at91_i2c f801c000.i2c: received nack
>> Jun  9 15:48:53 me20 kernel: at24 2-0050: write 32 at 128 --> -121 (753632)
>> Jun  9 15:48:53 me20 kernel: i2c i2c-2: at91_xfer: processing 1 messages:
>> Jun  9 15:48:53 me20 kernel: at91_i2c f801c000.i2c: transfer: write 34 bytes.
>> Jun  9 15:48:53 me20 kernel: at91_i2c f801c000.i2c: transfer complete
>> Jun  9 15:48:53 me20 kernel: at24 2-0050: write 32 at 128 --> 0 (753633)
>> Jun  9 15:48:53 me20 kernel: i2c i2c-2: at91_xfer: processing 1 messages:
>> Jun  9 15:48:53 me20 kernel: at91_i2c f801c000.i2c: transfer: write 34 bytes.
>> Jun  9 15:48:53 me20 kernel: at91_i2c f801c000.i2c: received nack
>> Jun  9 15:48:53 me20 kernel: at24 2-0050: write 32 at 160 --> -121 (753633)
>> Jun  9 15:48:53 me20 kernel: i2c i2c-2: at91_xfer: processing 1 messages:
>> Jun  9 15:48:53 me20 kernel: at91_i2c f801c000.i2c: transfer: write 34 bytes.
>> Jun  9 15:48:53 me20 kernel: at91_i2c f801c000.i2c: transfer complete
>> Jun  9 15:48:53 me20 kernel: at24 2-0050: write 32 at 160 --> 0 (753634)
>> ... snip ...
>> Jun  9 15:48:55 me20 kernel: i2c i2c-2: at91_xfer: processing 1 messages:
>> Jun  9 15:48:55 me20 kernel: at91_i2c f801c000.i2c: transfer: write 34 bytes.
>> Jun  9 15:48:55 me20 kernel: at91_i2c f801c000.i2c: received nack
>> Jun  9 15:48:55 me20 kernel: at24 2-0050: write 32 at 8128 --> -121 (753883)
>> Jun  9 15:48:55 me20 kernel: i2c i2c-2: at91_xfer: processing 1 messages:
>> Jun  9 15:48:55 me20 kernel: at91_i2c f801c000.i2c: transfer: write 34 bytes.
>> Jun  9 15:48:55 me20 kernel: at91_i2c f801c000.i2c: transfer complete
>> Jun  9 15:48:55 me20 kernel: at24 2-0050: write 32 at 8128 --> 0 (753884)
>> Jun  9 15:48:55 me20 kernel: i2c i2c-2: at91_xfer: processing 1 messages:
>> Jun  9 15:48:55 me20 kernel: at91_i2c f801c000.i2c: transfer: write 34 bytes.
>> Jun  9 15:48:55 me20 kernel: at91_i2c f801c000.i2c: received nack
>> Jun  9 15:48:55 me20 kernel: at24 2-0050: write 32 at 8160 --> -121 (753884)
>> Jun  9 15:48:55 me20 kernel: i2c i2c-2: at91_xfer: processing 1 messages:
>> Jun  9 15:48:55 me20 kernel: at91_i2c f801c000.i2c: transfer: write 34 bytes.
>> Jun  9 15:48:55 me20 kernel: at91_i2c f801c000.i2c: transfer complete
>> Jun  9 15:48:55 me20 kernel: at24 2-0050: write 32 at 8160 --> 0 (753885)
> 
> could you please apply this patch-set [1] and let us know if it 
> addresses your issue?
> 
> Thanks and best regards,
> Codrin
> 
> https://patchwork.ozlabs.org/project/linux-i2c/list/?series=255408

That series does indeed help! I'll reply with a tested-by etc on the
first two patches, I can't test patch 3/3 with my sama5d3 board...

Thank you very much!

Cheers,
Peter

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