Handling I2C eeprom devices

Handling I2C eeprom devices

[Patryk]

Hi,
I've got a question regarding how to handle I2C eeprom devices. I see
that in the kernel/drivers/misc/eeprom there are not that many drivers
available. Does it mean that they support various chips that do not
necessarily come from one vendor?
Looking at example at24.c, in the compatible properties I see that all
of them refers to atmel, however when I compared the following
devices: AT24C04C and BRCB008GWZ, at the first glance they look kinda
similar:
- they are organized internally in the same way - 1024 x 8 (8K)
- read/write commands looks the same

I'm not asking you to tell me whether or not it's possible this driver
at24 with the device I need (BRCB008GWZ), rather I would like to get a
suggestion on how to approach this and what factors I should take into
account to make the right decision.

Best regards
Patryk

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Re: Handling I2C eeprom devices

[Rémi ESSAISSI]

Le 17/05/2024 à 15:33, Patryk a écrit :
> Hi,
> I've got a question regarding how to handle I2C eeprom devices. I see
> that in the kernel/drivers/misc/eeprom there are not that many drivers
> available. Does it mean that they support various chips that do not
> necessarily come from one vendor?
> Looking at example at24.c, in the compatible properties I see that all
> of them refers to atmel, however when I compared the following
> devices: AT24C04C and BRCB008GWZ, at the first glance they look kinda
> similar:
> - they are organized internally in the same way - 1024 x 8 (8K)



> - read/write commands looks the same
Those chips may look the "same", but they differ in the magic sequences 
to interact with them.
I mean, they have to be exactly the same to work, up to the timing that 
has to follow the specs by the milli or micro second for example.
(and sometimes even weird voltages to apply on this or that pin ... )

So your best friend is the Datasheet of your IC delivered by the 
vendor/constructor of that chip, that will give you the magic sequences 
to interact with it .

Your case should be easy as you already have more than a working 
"skeleton" ... .


Regards


> 
> I'm not asking you to tell me whether or not it's possible this driver
> at24 with the device I need (BRCB008GWZ), rather I would like to get a
> suggestion on how to approach this and what factors I should take into
> account to make the right decision.
> 
> Best regards
> Patryk
> 
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies@kernelnewbies.org
> https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies

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Re: Handling I2C eeprom devices

[jim.cromie]

On Fri, May 17, 2024 at 7:35 AM Patryk <pbiel7@gmail.com> wrote:
>
> Hi,
> I've got a question regarding how to handle I2C eeprom devices. I see
> that in the kernel/drivers/misc/eeprom there are not that many drivers
> available. Does it mean that they support various chips that do not
> necessarily come from one vendor?
> Looking at example at24.c, in the compatible properties I see that all
> of them refers to atmel, however when I compared the following
> devices: AT24C04C and BRCB008GWZ, at the first glance they look kinda
> similar:
> - they are organized internally in the same way - 1024 x 8 (8K)
> - read/write commands looks the same
>
> I'm not asking you to tell me whether or not it's possible this driver
> at24 with the device I need (BRCB008GWZ), rather I would like to get a
> suggestion on how to approach this and what factors I should take into
> account to make the right decision.
>
> Best regards
> Patryk
>

$ git ls-files | grep eprom | wc -l
89
[jimc@frodo linux.git]$ git ls-files | grep eprom\.h | wc -l
29
[jimc@frodo linux.git]$ git ls-files | grep eprom  | grep include
arch/parisc/include/asm/eisa_eeprom.h
arch/sparc/include/asm/eeprom.h
drivers/staging/rtl8723bs/include/rtw_eeprom.h
include/linux/eeprom_93cx6.h
include/linux/eeprom_93xx46.h
include/linux/spi/eeprom.h
include/media/tveeprom.h

Id look at those headers for similarity,
then the 2 c files in misc for similarity.

also the files under devicetree - thats ALL interface defn

you didnt say if those parts are I2C or SPI or what.

do you have the hardware ?

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