On Fri, Aug 09, 2019 at 01:53:55PM +0100, Joe Burmeister wrote: > Many, though not all, AT25s have an instruction for chip erase. > If there is one in the datasheet, it can be added to device tree. > Erase can then be done in userspace via the sysfs API with a new > "erase" device attribute. This matches the eeprom_93xx46 driver's > "erase". > > Signed-off-by: Joe Burmeister <joe.burmeister@xxxxxxxxxxxxx> > --- > .../devicetree/bindings/eeprom/at25.txt | 2 + > drivers/misc/eeprom/at25.c | 83 ++++++++++++++++++- > 2 files changed, 82 insertions(+), 3 deletions(-) > > diff --git a/Documentation/devicetree/bindings/eeprom/at25.txt b/Documentation/devicetree/bindings/eeprom/at25.txt > index b3bde97dc199..c65d11e14c7a 100644 > --- a/Documentation/devicetree/bindings/eeprom/at25.txt > +++ b/Documentation/devicetree/bindings/eeprom/at25.txt > @@ -19,6 +19,7 @@ Optional properties: > - spi-cpha : SPI shifted clock phase, as per spi-bus bindings. > - spi-cpol : SPI inverse clock polarity, as per spi-bus bindings. > - read-only : this parameter-less property disables writes to the eeprom > +- chip_erase_instruction : Chip erase instruction for this AT25, often 0xc7 or 0x62. This should be using '-' rather than '_', as per general DT conventions and as with the existing properties. > Obsolete legacy properties can be used in place of "size", "pagesize", > "address-width", and "read-only": > @@ -39,4 +40,5 @@ Example: > pagesize = <64>; > size = <32768>; > address-width = <16>; > + chip_erase_instruction = <0x62>; [...] > + /* Optional chip erase instruction */ > + device_property_read_u8(&spi->dev, "chip_erase_instruction", &at25->erase_instr); This will not behave as you expect, since you didn't mark the property as 8-bits. Read this as a u32 into the existing val temporary variable, as is done for pagesize. You can add a warnign if it's out-of-range. Thanks, Mark.
