iio: core: add char type for sysfs attributes

This patch introduces IIO_VAL_CHAR type for standard IIO attributes to
allow for attributes that needs to be represented by character rather
than a number. This is preparatory for introducing a new attribute whose
purpose is to describe thermocouple type, that can be i.e. "J", "K", etc..

The char-type value is stored in the first "value" integer that is passed
to the .[read/write]_raw() callbacks.

Note that in order to make it possible for the IIO core to correctly parse
this type (actually, to avoid integer parsing), it became mandatory for
any driver that wish to use IIO_VAL_CHAR on a writable attribute to
implement .write_raw_get_fmt().

Cc: Hartmut Knaack <[email protected]>
Cc: Lars-Peter Clausen <[email protected]>
Cc: Peter Meerwald-Stadler <[email protected]>
Cc: Colin Ian King <[email protected]>
Cc: Patrick Havelange <[email protected]>
Cc: Matt Weber <[email protected]>
Cc: Matt Ranostay <[email protected]>
Cc: Chuhong Yuan <[email protected]>
Cc: Daniel Gomez <[email protected]>
Cc: [email protected]
Signed-off-by: Andrea Merello <[email protected]>
Signed-off-by: Jonathan Cameron <[email protected]>

0 files changed, 0 insertions, 0 deletions