staging: speakup: add spk_io_ops struct to spk_synth

This patch adds spk_io_ops struct which contain those methods whose job is to
communicate with synth device. Currently, all comms with external synth
device use raw serial i/o. The idea is to group all methods which do the
actual communication with external device into this new struct. Then migrating
a serial-based synth over to an alternative to raw serial i/o will mean
swapping serial spk_io_ops instance with the io_ops instance of the new
method, making the migration simpler.

At the moment, this struct only contains one method, synth_out but more will
be added in future when migrating synths which require input functionality.
Also at the moment, synth_out method has one implementation which uses
serial i/o. Plan is to add an alternative.

Signed-off-by: Okash Khawaja <okash.khawaja@gmail.com>
Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 7 insertions, 0 deletions

diff --git a/drivers/staging/speakup/spk_types.h b/drivers/staging/speakup/spk_types.h
index 9541b9e65840..a446064b6c91 100644
--- a/drivers/staging/speakup/spk_types.h
+++ b/drivers/staging/speakup/spk_types.h
@@ -146,6 +146,12 @@ struct synth_indexing {
 	unsigned char currindex;
 };
 
+struct spk_synth;
+
+struct spk_io_ops {
+	int (*synth_out)(struct spk_synth *synth, const char ch);
+};
+
 struct spk_synth {
 	const char *name;
 	const char *version;
@@ -164,6 +170,7 @@ struct spk_synth {
 	struct var_t *vars;
 	int *default_pitch;
 	int *default_vol;
+	struct spk_io_ops *io_ops;
 	int (*probe)(struct spk_synth *synth);
 	void (*release)(void);
 	const char *(*synth_immediate)(struct spk_synth *synth,