Input: add support for Braille devices

- Add KEY_BRL_* input keys and K_BRL_* keycodes;
- Add emulation of how braille keyboards usually combine braille dots
  to the console keyboard driver;
- Add handling of unicode U+28xy diacritics.
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

drivers/char/keyboard.c

@@ -74,7 +74,7 @@ void compute_shiftstate(void);
 	k_self,		k_fn,		k_spec,		k_pad,\
 	k_dead,		k_cons,		k_cur,		k_shift,\
 	k_meta,		k_ascii,	k_lock,		k_lowercase,\
-	k_slock,	k_dead2,	k_ignore,	k_ignore
+	k_slock,	k_dead2,	k_brl,		k_ignore
 
 typedef void (k_handler_fn)(struct vc_data *vc, unsigned char value,
 			    char up_flag, struct pt_regs *regs);
@@ -100,7 +100,7 @@ static fn_handler_fn *fn_handler[] = { FN_HANDLERS };
 const int max_vals[] = {
 	255, ARRAY_SIZE(func_table) - 1, ARRAY_SIZE(fn_handler) - 1, NR_PAD - 1,
 	NR_DEAD - 1, 255, 3, NR_SHIFT - 1, 255, NR_ASCII - 1, NR_LOCK - 1,
-	255, NR_LOCK - 1, 255
+	255, NR_LOCK - 1, 255, NR_BRL - 1
 };
 
 const int NR_TYPES = ARRAY_SIZE(max_vals);
@@ -126,7 +126,7 @@ static unsigned long key_down[NBITS(KEY_MAX)];		/* keyboard key bitmap */
 static unsigned char shift_down[NR_SHIFT];		/* shift state counters.. */
 static int dead_key_next;
 static int npadch = -1;					/* -1 or number assembled on pad */
-static unsigned char diacr;
+static unsigned int diacr;
 static char rep;					/* flag telling character repeat */
 
 static unsigned char ledstate = 0xff;			/* undefined */
@@ -394,22 +394,30 @@ void compute_shiftstate(void)
  * Otherwise, conclude that DIACR was not combining after all,
  * queue it and return CH.
  */
-static unsigned char handle_diacr(struct vc_data *vc, unsigned char ch)
+static unsigned int handle_diacr(struct vc_data *vc, unsigned int ch)
 {
-	int d = diacr;
+	unsigned int d = diacr;
 	unsigned int i;
 
 	diacr = 0;
 
-	for (i = 0; i < accent_table_size; i++) {
+	if ((d & ~0xff) == BRL_UC_ROW) {
+		if ((ch & ~0xff) == BRL_UC_ROW)
+			return d | ch;
+	} else {
+		for (i = 0; i < accent_table_size; i++)
 			if (accent_table[i].diacr == d && accent_table[i].base == ch)
 				return accent_table[i].result;
 	}
 
-	if (ch == ' ' || ch == d)
+	if (ch == ' ' || ch == (BRL_UC_ROW|0) || ch == d)
 		return d;
 
+	if (kbd->kbdmode == VC_UNICODE)
+		to_utf8(vc, d);
+	else if (d < 0x100)
 		put_queue(vc, d);
+
 	return ch;
 }
 
@@ -419,6 +427,9 @@ static unsigned char handle_diacr(struct vc_data *vc, unsigned char ch)
 static void fn_enter(struct vc_data *vc, struct pt_regs *regs)
 {
 	if (diacr) {
+		if (kbd->kbdmode == VC_UNICODE)
+			to_utf8(vc, diacr);
+		else if (diacr < 0x100)
 			put_queue(vc, diacr);
 		diacr = 0;
 	}
@@ -615,7 +626,7 @@ static void k_lowercase(struct vc_data *vc, unsigned char value, char up_flag, s
 	printk(KERN_ERR "keyboard.c: k_lowercase was called - impossible\n");
 }
 
-static void k_self(struct vc_data *vc, unsigned char value, char up_flag, struct pt_regs *regs)
+static void k_unicode(struct vc_data *vc, unsigned int value, char up_flag, struct pt_regs *regs)
 {
 	if (up_flag)
 		return;		/* no action, if this is a key release */
@@ -628,6 +639,9 @@ static void k_self(struct vc_data *vc, unsigned char value, char up_flag, struct
 		diacr = value;
 		return;
 	}
+	if (kbd->kbdmode == VC_UNICODE)
+		to_utf8(vc, value);
+	else if (value < 0x100)
 		put_queue(vc, value);
 }
 
@@ -636,13 +650,23 @@ static void k_self(struct vc_data *vc, unsigned char value, char up_flag, struct
  * dead keys modifying the same character. Very useful
  * for Vietnamese.
  */
-static void k_dead2(struct vc_data *vc, unsigned char value, char up_flag, struct pt_regs *regs)
+static void k_deadunicode(struct vc_data *vc, unsigned int value, char up_flag, struct pt_regs *regs)
 {
 	if (up_flag)
 		return;
 	diacr = (diacr ? handle_diacr(vc, value) : value);
 }
 
+static void k_self(struct vc_data *vc, unsigned char value, char up_flag, struct pt_regs *regs)
+{
+	k_unicode(vc, value, up_flag, regs);
+}
+
+static void k_dead2(struct vc_data *vc, unsigned char value, char up_flag, struct pt_regs *regs)
+{
+	k_deadunicode(vc, value, up_flag, regs);
+}
+
 /*
  * Obsolete - for backwards compatibility only
  */
@@ -650,7 +674,7 @@ static void k_dead(struct vc_data *vc, unsigned char value, char up_flag, struct
 {
 	static unsigned char ret_diacr[NR_DEAD] = {'`', '\'', '^', '~', '"', ',' };
 	value = ret_diacr[value];
-	k_dead2(vc, value, up_flag, regs);
+	k_deadunicode(vc, value, up_flag, regs);
 }
 
 static void k_cons(struct vc_data *vc, unsigned char value, char up_flag, struct pt_regs *regs)
@@ -835,6 +859,62 @@ 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 void k_brl(struct vc_data *vc, unsigned char value, char up_flag, struct pt_regs *regs)
+{
+	static unsigned pressed,committing;
+	static unsigned long releasestart;
+
+	if (kbd->kbdmode != VC_UNICODE) {
+		if (!up_flag)
+			printk("keyboard mode must be unicode for braille patterns\n");
+		return;
+	}
+
+	if (!value) {
+		k_unicode(vc, BRL_UC_ROW, up_flag, regs);
+		return;
+	}
+
+	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 ||
+			    jiffies - releasestart > (brl_timeout * HZ) / 1000) {
+				committing = pressed;
+				releasestart = jiffies;
+			}
+			pressed &= ~(1 << (value - 1));
+			if (!pressed) {
+				if (committing) {
+					k_unicode(vc, BRL_UC_ROW | committing, 0, regs);
+					committing = 0;
+				}
+			}
+		} else {
+			if (committing) {
+				k_unicode(vc, BRL_UC_ROW | committing, 0, regs);
+				committing = 0;
+			}
+			pressed &= ~(1 << (value - 1));
+		}
+	} else {
+		pressed |= 1 << (value - 1);
+		if (!brl_timeout)
+			committing = pressed;
+	}
+}
+
 /*
  * The leds display either (i) the status of NumLock, CapsLock, ScrollLock,
  * or (ii) whatever pattern of lights people want to show using KDSETLED,
@@ -1125,9 +1205,13 @@ static void kbd_keycode(unsigned int keycode, int down,
 	}
 
 	if (keycode > NR_KEYS)
+		if (keycode >= KEY_BRL_DOT1 && keycode <= KEY_BRL_DOT8)
+			keysym = K(KT_BRL, keycode - KEY_BRL_DOT1 + 1);
+		else
 			return;
-
+	else
 		keysym = key_map[keycode];
+
 	type = KTYP(keysym);
 
 	if (type < 0xf0) {

include/linux/input.h

@@ -512,6 +512,15 @@ struct input_absinfo {
 #define KEY_FN_S		0x1e3
 #define KEY_FN_B		0x1e4
 
+#define KEY_BRL_DOT1		0x1f1
+#define KEY_BRL_DOT2		0x1f2
+#define KEY_BRL_DOT3		0x1f3
+#define KEY_BRL_DOT4		0x1f4
+#define KEY_BRL_DOT5		0x1f5
+#define KEY_BRL_DOT6		0x1f6
+#define KEY_BRL_DOT7		0x1f7
+#define KEY_BRL_DOT8		0x1f8
+
 /* We avoid low common keys in module aliases so they don't get huge. */
 #define KEY_MIN_INTERESTING	KEY_MUTE
 #define KEY_MAX			0x1ff

include/linux/kbd_kern.h

@@ -135,6 +135,8 @@ static inline void chg_vc_kbd_led(struct kbd_struct * kbd, int flag)
 
 #define U(x) ((x) ^ 0xf000)
 
+#define BRL_UC_ROW 0x2800
+
 /* keyboard.c */
 
 struct console;

include/linux/keyboard.h

@@ -44,6 +44,7 @@ extern unsigned short plain_map[NR_KEYS];
 #define KT_ASCII	9
 #define KT_LOCK		10
 #define KT_SLOCK	12
+#define KT_BRL		14
 
 #define K(t,v)		(((t)<<8)|(v))
 #define KTYP(x)		((x) >> 8)
@@ -427,5 +428,17 @@ extern unsigned short plain_map[NR_KEYS];
 
 #define NR_LOCK		8
 
+#define K_BRL_BLANK     K(KT_BRL, 0)
+#define K_BRL_DOT1      K(KT_BRL, 1)
+#define K_BRL_DOT2      K(KT_BRL, 2)
+#define K_BRL_DOT3      K(KT_BRL, 3)
+#define K_BRL_DOT4      K(KT_BRL, 4)
+#define K_BRL_DOT5      K(KT_BRL, 5)
+#define K_BRL_DOT6      K(KT_BRL, 6)
+#define K_BRL_DOT7      K(KT_BRL, 7)
+#define K_BRL_DOT8      K(KT_BRL, 8)
+
+#define NR_BRL		9
+
 #define MAX_DIACR	256
 #endif