Reimplement the RC-5 decoder state machine. Code is now clear, and works
properly. It is also simpler than the previous implementations.
Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx>
diff --git a/drivers/media/IR/ir-rc5-decoder.c b/drivers/media/IR/ir-rc5-decoder.c
index 4fb3ce4..a62277b 100644
--- a/drivers/media/IR/ir-rc5-decoder.c
+++ b/drivers/media/IR/ir-rc5-decoder.c
@@ -15,19 +15,17 @@
/*
* This code only handles 14 bits RC-5 protocols. There are other variants
* that use a different number of bits. This is currently unsupported
+ * It considers a carrier of 36 kHz, with a total of 14 bits, where
+ * the first two bits are start bits, and a third one is a filing bit
*/
#include <media/ir-core.h>
+static unsigned int ir_rc5_remote_gap = 888888;
+
#define RC5_NBITS 14
-#define RC5_HALFBIT 888888 /* ns */
-#define RC5_BIT (RC5_HALFBIT * 2)
-#define RC5_DURATION (RC5_BIT * RC5_NBITS)
-
-#define is_rc5_halfbit(nsec) ((ev->delta.tv_nsec >= RC5_HALFBIT / 2) && \
- (ev->delta.tv_nsec < RC5_HALFBIT + RC5_HALFBIT / 2))
-
-#define n_half(nsec) ((ev->delta.tv_nsec + RC5_HALFBIT / 2) / RC5_HALFBIT)
+#define RC5_BIT (ir_rc5_remote_gap * 2)
+#define RC5_DURATION (ir_rc5_remote_gap * RC5_NBITS)
/* Used to register rc5_decoder clients */
static LIST_HEAD(decoder_list);
@@ -35,19 +33,8 @@ static spinlock_t decoder_lock;
enum rc5_state {
STATE_INACTIVE,
- STATE_START2_SPACE,
- STATE_START2_MARK,
STATE_MARKSPACE,
- STATE_TRAILER_MARK,
-};
-
-static char *st_name[] = {
- "Inactive",
- "start2 sapce",
- "start2 mark",
- "mark",
- "space",
- "trailer"
+ STATE_TRAILER,
};
struct rc5_code {
@@ -63,8 +50,7 @@ struct decoder_data {
/* State machine control */
enum rc5_state state;
struct rc5_code rc5_code;
- unsigned n_half;
- unsigned count;
+ unsigned code, elapsed, last_bit, last_code;
};
@@ -147,7 +133,7 @@ static int ir_rc5_decode(struct input_dev *input_dev,
{
struct decoder_data *data;
struct ir_input_dev *ir_dev = input_get_drvdata(input_dev);
- int bit, last_bit, n_half;
+ int is_pulse, scancode, delta, toggle;
data = get_decoder_data(ir_dev);
if (!data)
@@ -156,122 +142,79 @@ static int ir_rc5_decode(struct input_dev *input_dev,
if (!data->enabled)
return 0;
- /* Except for the initial event, what matters is the previous bit */
- bit = (ev->type & IR_PULSE) ? 1 : 0;
+ delta = DIV_ROUND_CLOSEST(ev->delta.tv_nsec, ir_rc5_remote_gap);
- last_bit = !bit;
-
- /* Discards spurious space last_bits when inactive */
+ /* The duration time refers to the last bit time */
+ is_pulse = (ev->type & IR_PULSE) ? 1 : 0;
/* Very long delays are considered as start events */
- if (ev->delta.tv_nsec > RC5_DURATION + RC5_HALFBIT / 2)
- data->state = STATE_INACTIVE;
-
- if (ev->type & IR_START_EVENT)
+ if (delta > RC5_DURATION || (ev->type & IR_START_EVENT))
data->state = STATE_INACTIVE;
switch (data->state) {
case STATE_INACTIVE:
-IR_dprintk(1, "currently inative. Received bit (%s) @%luus\n",
- last_bit ? "pulse" : "space",
- (ev->delta.tv_nsec + 500) / 1000);
+ IR_dprintk(2, "currently inative. Start bit (%s) @%uus\n",
+ is_pulse ? "pulse" : "space",
+ (unsigned)(ev->delta.tv_nsec + 500) / 1000);
/* Discards the initial start space */
- if (bit)
- return 0;
- data->count = 0;
- data->n_half = 0;
- memset (&data->rc5_code, 0, sizeof(data->rc5_code));
-
- data->state = STATE_START2_SPACE;
- return 0;
- case STATE_START2_SPACE:
- if (last_bit)
+ if (!is_pulse)
goto err;
- if (!is_rc5_halfbit(ev->delta.tv_nsec))
- goto err;
- data->state = STATE_START2_MARK;
- return 0;
- case STATE_START2_MARK:
- if (!last_bit)
- goto err;
-
- if (!is_rc5_halfbit(ev->delta.tv_nsec))
- goto err;
-
+ data->code = 1;
+ data->last_bit = 1;
+ data->elapsed = 0;
+ memset(&data->rc5_code, 0, sizeof(data->rc5_code));
data->state = STATE_MARKSPACE;
return 0;
case STATE_MARKSPACE:
- n_half = n_half(ev->delta.tv_nsec);
- if (n_half < 1 || n_half > 3) {
- IR_dprintk(1, "Decode failed at %d-th bit (%s) @%luus\n",
- data->count,
- last_bit ? "pulse" : "space",
- (ev->delta.tv_nsec + 500) / 1000);
-printk("%d halves\n", n_half);
- goto err2;
- }
- data->n_half += n_half;
+ if (delta != 1)
+ data->last_bit = data->last_bit ? 0 : 1;
- if (!last_bit)
+ data->elapsed += delta;
+
+ if ((data->elapsed % 2) == 1)
return 0;
- /* Got one complete mark/space cycle */
+ data->code <<= 1;
+ data->code |= data->last_bit;
- bit = ((data->count + 1) * 2)/ data->n_half;
+ /* Fill the 2 unused bits at the command with 0 */
+ if (data->elapsed / 2 == 6)
+ data->code <<= 2;
-printk("%d halves, %d bits\n", n_half, bit);
+ if (data->elapsed >= (RC5_NBITS - 1) * 2) {
+ scancode = data->code;
-#if 1 /* SANITY check - while testing the decoder */
- if (bit > 1) {
- IR_dprintk(1, "Decoder HAS failed at %d-th bit (%s) @%luus\n",
- data->count,
- last_bit ? "pulse" : "space",
- (ev->delta.tv_nsec + 500) / 1000);
+ /* Check for the start bits */
+ if ((scancode & 0xc000) != 0xc000) {
+ IR_dprintk(1, "Code 0x%04x doesn't have two start bits. It is not RC-5\n", scancode);
+ goto err;
+ }
- goto err2;
- }
-#endif
- /* Ok, we've got a valid bit. proccess it */
- if (bit) {
- int shift = data->count;
+ toggle = (scancode & 0x2000) ? 1 : 0;
- /*
- * RC-5 transmit bytes on this temporal order:
- * address | not address | command | not command
- */
- if (shift < 8) {
- data->rc5_code.address |= 1 << shift;
+ if (scancode == data->last_code) {
+ IR_dprintk(1, "RC-5 repeat\n");
+ ir_repeat(input_dev);
} else {
- data->rc5_code.command |= 1 << (shift - 8);
+ data->last_code = scancode;
+ scancode &= 0x1fff;
+ IR_dprintk(1, "RC-5 scancode 0x%04x\n", scancode);
+
+ ir_keydown(input_dev, scancode, 0);
}
- }
- IR_dprintk(1, "RC-5: bit #%d: %d (%d)\n",
- data->count, bit, data->n_half);
- if (++data->count >= RC5_NBITS) {
- u32 scancode;
- scancode = data->rc5_code.address << 8 |
- data->rc5_code.command;
- IR_dprintk(1, "RC-5 scancode 0x%04x\n", scancode);
-
- ir_keydown(input_dev, scancode, 0);
-
- data->state = STATE_TRAILER_MARK;
+ data->state = STATE_TRAILER;
}
return 0;
- case STATE_TRAILER_MARK:
- if (!last_bit)
- goto err;
+ case STATE_TRAILER:
data->state = STATE_INACTIVE;
return 0;
}
err:
- IR_dprintk(1, "RC-5 decoded failed at state %s (%s) @ %luus\n",
- st_name[data->state],
- bit ? "pulse" : "space",
+ IR_dprintk(1, "RC-5 decoded failed at %s @ %luus\n",
+ is_pulse ? "pulse" : "space",
(ev->delta.tv_nsec + 500) / 1000);
-err2:
data->state = STATE_INACTIVE;
return -EINVAL;
}
--
1.6.6.1
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