Messages in this thread | | | Date | Wed, 5 Dec 2012 17:41:53 +0100 | From | Wolfram Sang <> | Subject | Re: [PATCH RFC] misc/at24: distinguish between eeprom and fram chips |
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Hi,
On Wed, Dec 05, 2012 at 10:43:07AM +0100, Lars Poeschel wrote: > I see there where to much "no"s to get anything in, but thank you for > your comments and explanations.
Not necessarily, just not in this form :)
> > > > I wanted to use a fm24c04 i2c fram chip with linux. I grepped the source > > > and found nothing. I later found that my chip can be handled by at24 > > > eeprom driver. It creates a sysfs file called eeprom to read from and > > > write to the chip. Userspace has no chance to distinguish if it is > > > writing an eeprom or a fram chip. > > > > Why should it? > > Because writes are much faster and it doesn't have to take care on erase > cycles. It could use other write strategies on such devices and update > informations that have to survive power downs more often.
I agree. I think that a seperate attribute named e.g. 'page_size' would be more helpful than renaming the binary file to fram?
> > The method of accessing EEPROMs is used by way more chips than FRAMs. > > So, I'd prefer to have the text updated more generic like "EEPROMs and > > similar devices like RAMs, ROMs, etc...". Describing setting .flags in > > Kconfig is overkill. > > A patch updating Kconfig is below.
Looks good from a glimpse, will apply it later.
> No one knows all chips out there. > For the fm24c04 I use page_size != chip_size. It does not buffer but it has > two pages, 256 bytes each.
Yup, it uses two I2C adresses...
Thanks,
Wolfram
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