staging: speakup: make input functionality swappable

This moves functions which take input from external synth, into struct
spk_io_ops. The calling code then uses serial implementation of those methods
through spk_io_ops. That way we can add a parallel TTY-based implementation and
simply replace serial with TTY. That is what the next patch in this series does.

speakup_decext.c has get_last_char function which reads the most recent
available character from the synth. This patch changes that by defining
read_buff_add callback method of spk_syth and letting that update the last_char
global character read from the synth. read_buff_add is called from ISR, so
there is a possibility for last_char to be stale. Therefore it is marked as
volatile. It also pulls a repeated get_index implementation into synth.c, to
be used as a utility function.

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, 8 insertions, 2 deletions

diff --git a/drivers/staging/speakup/synth.c b/drivers/staging/speakup/synth.c
index 352e9eebc3de..9c2aa1b8b0ac 100644
--- a/drivers/staging/speakup/synth.c
+++ b/drivers/staging/speakup/synth.c
@@ -124,6 +124,12 @@ void spk_synth_flush(struct spk_synth *synth)
 }
 EXPORT_SYMBOL_GPL(spk_synth_flush);
 
+unsigned char spk_synth_get_index(struct spk_synth *synth)
+{
+	return synth->io_ops->synth_in_nowait();
+}
+EXPORT_SYMBOL_GPL(spk_synth_get_index);
+
 int spk_synth_is_alive_nop(struct spk_synth *synth)
 {
 	synth->alive = 1;
@@ -249,7 +255,7 @@ void spk_reset_index_count(int sc)
 	if (first)
 		first = 0;
 	else
-		synth->get_index();
+		synth->get_index(synth);
 	index_count = 0;
 	sentence_count = sc;
 }
@@ -282,7 +288,7 @@ void synth_insert_next_index(int sent_num)
 
 void spk_get_index_count(int *linecount, int *sentcount)
 {
-	int ind = synth->get_index();
+	int ind = synth->get_index(synth);
 
 	if (ind) {
 		sentence_count = ind % 10;