The change removes redundant sysfs binary file boundary checks,
since this task is already done on caller side in fs/sysfs/file.c

Note, on file size overflow read() now returns 0, and this is a
correct and expected EOF notification according to POSIX.
Signed-off-by: NVladimir Zapolskiy <vz@mleia.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

It is a bit subtle when to correctly increase the buffer index when
reading. Make this clearer by adding some more comments and pointers to
the docs.
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

After more discussion, brave users, and additional datasheet evaluation,
some API updates for the new I2C slave framework became imminent. The
slave events now get some easier to understand naming. Also, the event
handling has been simplified to only need a single call to the slave
callback when an action by the backend is required.
Reported-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Acked-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Due to a copy&paste error, the last byte of the shared memory was not
accessible via sysfs.
Reported-by: NDebora Grosse <debora@mds.com>
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

The first user of the i2c-slave interface is an eeprom simulator. It is
a shared memory which can be accessed by the remote master via I2C and
locally via sysfs.
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>