Re: [PATCH v2] eeprom: at25: Add DT support for EEPROMs with odd address bits

From: Rob Herring
Date: Tue Dec 12 2017 - 15:54:57 EST


On Fri, Dec 08, 2017 at 02:46:41PM +0100, Geert Uytterhoeven wrote:
> Certain EEPROMS have a size that is larger than the number of address
> bytes would allow, and store the MSB of the address in bit 3 of the
> instruction byte.
>
> This can be described in platform data using EE_INSTR_BIT3_IS_ADDR, or
> in DT using the obsolete legacy "at25,addr-mode" property.
> But currently there exists no non-deprecated way to describe this in DT.
>
> Hence extend the existing "address-width" DT property to allow
> specifying 9 address bits, and enable support for that in the driver.
>
> This has been tested with a Microchip 25LC040A.
>
> Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
> ---
> v2:
> - Do not consider odd address widths of 17 or 25 bits,
> - Move handling inside the switch() statement.
> ---
> Documentation/devicetree/bindings/eeprom/at25.txt | 4 +++-
> drivers/misc/eeprom/at25.c | 3 +++
> 2 files changed, 6 insertions(+), 1 deletion(-)

Reviewed-by: Rob Herring <robh@xxxxxxxxxx>