media: rc: implement zilog transmitter

This code implements the transmitter which is currently implemented
in the staging lirc_zilog driver.

The new code does not need a signal database, iow. the
haup-ir-blaster.bin firmware file is no longer needed, and the driver
does not know anything about the keycodes in that file.

Instead, the new driver can send raw IR, but the hardware is limited
to few different lengths of pulse and spaces, so it is best to use
generated IR rather than recorded IR.
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

include/media/i2c/ir-kbd-i2c.h

@@ -23,6 +23,11 @@ struct IR_i2c {
 	int                    (*get_key)(struct IR_i2c *ir,
 					  enum rc_proto *protocol,
 					  u32 *scancode, u8 *toggle);
+	/* tx */
+	struct i2c_client      *tx_c;
+	struct mutex	       lock;	/* do not poll Rx during Tx */
+	unsigned int	       carrier;
+	unsigned int	       duty_cycle;
 };
 
 enum ir_kbd_get_key_fn {