drivers: Introduce dev_set_name() ...

Introduce dev_set_name() in order to hide implementation details of
setting device's name so it'd be easier to change it.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

nvmem: Introduce nvmem_cell_get_and_read() ...

Introduce nvmem_cell_get_and_read() that combines getting a NVMEM cell
by name and reading its contents.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Reviewed-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

nvmem: Use name from struct nvmem_config for cdev ...

Original name, 'nvmemN', doesn't really give any hint about which
physical HW it may represent, so change the code to either pick up an
DT alias or use the name passed via 'struct nvmem_config'.

Cc: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Tested-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

rename file_operations -> cdev_operations ...

Linux also has struct file_operations which are something different.
Rename our file_operations to cdev_operations which better matches
what we have.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

drivers: add nvmem framework from kernel ...

Add the nvmem framework from Linux.

Based on the v4.4-rc3 version.

Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>