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Not all FRAM chips have a device ID and implement the corresponding read
command. For such chips this led to the following error on module
loading:
at25 spi2.0: Error: no Cypress FRAM (id 00)
The device ID contains the memory size, so devices without this ID are
supported now by setting the size manually in Devicetree using the
"size" property.
Tested with FM25L16B and "size = <2048>;":
at25 spi2.0: 2 KByte fm25 fram, pagesize 4096
According to Infineon/Cypress datasheets, these FRAMs have a device ID:
FM25V01A
FM25V02A
FM25V05
FM25V10
FM25V20A
FM25VN10
but these do not:
FM25040B
FM25640B
FM25C160B
FM25CL64B
FM25L04B
FM25L16B
FM25W256
So all "FM25V*" FRAMs and only these have a device ID. The letter after
"FM25" (V/C/L/W) only describes the voltage range, though.
Link: https://lore.kernel.org/all/20250401133148.38330-1-m.heidelberg@cab.de/
Signed-off-by: Markus Heidelberg <m.heidelberg@cab.de>
Reviewed-by: Alexander Sverdlin <alexander.sverdlin@gmail.com>
Link: https://lore.kernel.org/r/20250815095839.4219-3-m.heidelberg@cab.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.