Input: allow using several chords for braille

For coping with bad keyboards, permit to type a braille pattern by
pressing several chords. By default, only one chord is needed.

Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

1 files changed, 28 insertions, 10 deletions

diff --git a/drivers/char/keyboard.c b/drivers/char/keyboard.c
index 935670a3cd98..5755b7e5f187 100644
--- a/drivers/char/keyboard.c
+++ b/drivers/char/keyboard.c
@@ -860,9 +860,32 @@ static void k_slock(struct vc_data *vc, unsigned char value, char up_flag, struc
 }
 
 /* by default, 300ms interval for combination release */
-static long brl_timeout = 300;
-MODULE_PARM_DESC(brl_timeout, "Braille keys release delay in ms (0 for combination on first release, < 0 for dead characters)");
-module_param(brl_timeout, long, 0644);
+static unsigned brl_timeout = 300;
+MODULE_PARM_DESC(brl_timeout, "Braille keys release delay in ms (0 for commit on first key release)");
+module_param(brl_timeout, uint, 0644);
+
+static unsigned brl_nbchords = 1;
+MODULE_PARM_DESC(brl_nbchords, "Number of chords that produce a braille pattern (0 for dead chords)");
+module_param(brl_nbchords, uint, 0644);
+
+static void k_brlcommit(struct vc_data *vc, unsigned int pattern, char up_flag, struct pt_regs *regs)
+{
+        static unsigned long chords;
+        static unsigned committed;
+
+        if (!brl_nbchords)
+                k_deadunicode(vc, BRL_UC_ROW | pattern, up_flag, regs);
+        else {
+                committed |= pattern;
+                chords++;
+                if (chords == brl_nbchords) {
+                        k_unicode(vc, BRL_UC_ROW | committed, up_flag, regs);
+                        chords = 0;
+                        committed = 0;
+                }
+        }
+}
+
 static void k_brl(struct vc_data *vc, unsigned char value, char up_flag, struct pt_regs *regs)
 {
         static unsigned pressed,committing;
@@ -882,11 +905,6 @@ static void k_brl(struct vc_data *vc, unsigned char value, char up_flag, struct
         if (value > 8)
                 return;
 
-        if (brl_timeout < 0) {
-                k_deadunicode(vc, BRL_UC_ROW | (1 << (value - 1)), up_flag, regs);
-                return;
-        }
-
         if (up_flag) {
                 if (brl_timeout) {
                         if (!committing ||
@@ -897,13 +915,13 @@ static void k_brl(struct vc_data *vc, unsigned char value, char up_flag, struct
                         pressed &= ~(1 << (value - 1));
                         if (!pressed) {
                                 if (committing) {
-                                        k_unicode(vc, BRL_UC_ROW | committing, 0, regs);
+                                        k_brlcommit(vc, committing, 0, regs);
                                         committing = 0;
                                 }
                         }
                 } else {
                         if (committing) {
-                                k_unicode(vc, BRL_UC_ROW | committing, 0, regs);
+                                k_brlcommit(vc, committing, 0, regs);
                                 committing = 0;
                         }
                         pressed &= ~(1 << (value - 1));