[PATCH 2/5] ARM: dts: at91: sam9x60-curiosity: Fix EEPROM type

[Eugen Hristev]

On 7/5/23 23:16, Alexander Dahl wrote:
> From: Alexander Dahl <ada at thorsis.com>
> 
> The user guide says it's a Microchip 24AA025E48 serial EEPROM, which is
> a 2-Kbit I2C Serial EEPROM with EUI-48™ Identity.  This is the chip
> actually populated on board EV40E67A rev 4.
> 
> Signed-off-by: Alexander Dahl <ada at thorsis.com>
> ---
> 
> Notes:
>      Sadly this did not fix the problem, that I could not access that
>      eeprom through I²C.
> 
>   arch/arm/dts/at91-sam9x60_curiosity.dts | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/arm/dts/at91-sam9x60_curiosity.dts b/arch/arm/dts/at91-sam9x60_curiosity.dts
> index d6ae3d648d..da5e19b66b 100644
> --- a/arch/arm/dts/at91-sam9x60_curiosity.dts
> +++ b/arch/arm/dts/at91-sam9x60_curiosity.dts
> @@ -31,7 +31,7 @@
>   					status = "okay";
>   
>   					eeprom at 53 {
> -						compatible = "atmel,24c32";
> +						compatible = "atmel,24c02";
>   						reg = <0x53>;
>   						pagesize = <16>;
>   					};

Hello Alexander,

Thank you for the patch.

I remember I tested this a while back and I remember that the 24c32 
compatible is not correct for this eeprom.

I have this commit that fixed it for sam9x60ek board:

commit 5ae89b3cfe842ecbb5153a95e2e3ac404abe543c
Author: Eugen Hristev <eugen.hristev at collabora.com>
Date:   Thu May 26 17:04:56 2022 +0300

     ARM: dts: at91: sam9x60ek: fix eeprom compatible



24c32 should be 32K and 24c02 is 2K .

I remember that with 24c32 it works, but when you read , the offset 
changes, and then you read the same data multiple times, as if the 2K is 
multiplied to have the 32K the driver thinks it has.

Do you have any reasoning for wanting to change the compatible to 24c32 ?
I am trying to understand how you found that 24c32 is better.

Eugen