Re: [RESEND PATCH 0/9] eeprom: at24: at24cs series serial number read

[Bartosz Golaszewski]

2015-10-21 16:23 GMT+02:00 Peter Korsgaard :
>> "Bartosz" == Bartosz Golaszewski  writes:
>
>  >> As the serial number is available on a separate i2c address, wouldn't
>  >> it be simpler to handle these as special (read only) device variants and
>  >> instantiate E.G. a 24c64 (for the normal data) and a 24cs64 (for the
>  >> serial)?
>  >>
>
>  > Hi Peter,
>
>  > I wanted to respond that this way we would not be protected from
>  > concurrent accesses, but then I saw I didn't actually include any
>  > locks in the serial read function - my bad. It needs to be fixed as
>  > both memory blocks share the same address pointer.
>
>  > I'll resend the series.
>
> But we're protected by the i2c bus lock, right? You do a single
> i2c_transfer to read the serial number.

Why the at24->lock then?

Best regards,
Bartosz Golaszewski
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Re: [RESEND PATCH 0/9] eeprom: at24: at24cs series serial number read

[Peter Korsgaard]

> "Bartosz" == Bartosz Golaszewski  writes:

Hi,

 >> > I wanted to respond that this way we would not be protected from
 >> > concurrent accesses, but then I saw I didn't actually include any
 >> > locks in the serial read function - my bad. It needs to be fixed as
 >> > both memory blocks share the same address pointer.
 >> 
 >> > I'll resend the series.
 >> 
 >> But we're protected by the i2c bus lock, right? You do a single
 >> i2c_transfer to read the serial number.

 > Why the at24->lock then?

I'm not sure. Wolfram?

-- 
Bye, Peter Korsgaard 
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Re: [RESEND PATCH 0/9] eeprom: at24: at24cs series serial number read

[Peter Korsgaard]

> "Bartosz" == Bartosz Golaszewski  writes:

 >> As the serial number is available on a separate i2c address, wouldn't
 >> it be simpler to handle these as special (read only) device variants and
 >> instantiate E.G. a 24c64 (for the normal data) and a 24cs64 (for the
 >> serial)?
 >> 

 > Hi Peter,

 > I wanted to respond that this way we would not be protected from
 > concurrent accesses, but then I saw I didn't actually include any
 > locks in the serial read function - my bad. It needs to be fixed as
 > both memory blocks share the same address pointer.

 > I'll resend the series.

But we're protected by the i2c bus lock, right? You do a single
i2c_transfer to read the serial number.

-- 
Venlig hilsen,
Peter Korsgaard 
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Re: [RESEND PATCH 0/9] eeprom: at24: at24cs series serial number read

[Bartosz Golaszewski]

2015-10-21 13:03 GMT+02:00 Peter Korsgaard :
>> "Bartosz" == Bartosz Golaszewski  writes:
>
>  > Chips from the at24cs EEPROM series have an additional read-only memory 
> area
>  > containing a factory pre-programmed serial number. In order to access it, a
>  > dummy write must be executed before reading the serial number bytes.
>
>  > This series adds support for reading the serial number through a sysfs
>  > attribute.
>
>  > While we're at it: some of the patches contain readability tweaks and code
>  > organization fixes.
>
>  > Tested with at24cs64 and at24cs02 chips (for both 16 and 8 bit address
>  > pointers).
>
> As the serial number is available on a separate i2c address, wouldn't
> it be simpler to handle these as special (read only) device variants and
> instantiate E.G. a 24c64 (for the normal data) and a 24cs64 (for the
> serial)?
>

Hi Peter,

I wanted to respond that this way we would not be protected from
concurrent accesses, but then I saw I didn't actually include any
locks in the serial read function - my bad. It needs to be fixed as
both memory blocks share the same address pointer.

I'll resend the series.

Best regards,
Bartosz Golaszewski
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Re: [RESEND PATCH 0/9] eeprom: at24: at24cs series serial number read

[Peter Korsgaard]

> "Bartosz" == Bartosz Golaszewski  writes:

 > Chips from the at24cs EEPROM series have an additional read-only memory area
 > containing a factory pre-programmed serial number. In order to access it, a
 > dummy write must be executed before reading the serial number bytes.

 > This series adds support for reading the serial number through a sysfs
 > attribute.

 > While we're at it: some of the patches contain readability tweaks and code
 > organization fixes.

 > Tested with at24cs64 and at24cs02 chips (for both 16 and 8 bit address
 > pointers).

As the serial number is available on a separate i2c address, wouldn't
it be simpler to handle these as special (read only) device variants and
instantiate E.G. a 24c64 (for the normal data) and a 24cs64 (for the
serial)?

-- 
Bye, Peter Korsgaard
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