Commit 844a4f45 authored by Antti Seppälä's avatar Antti Seppälä Committed by Mauro Carvalho Chehab

[media] rc: rc-ir-raw: Add Manchester encoder (phase encoder) helper

Adding a simple Manchester encoder to rc-core.
Manchester coding is used by at least RC-5 and RC-6 protocols and their
variants.
Signed-off-by: default avatarAntti Seppälä <a.seppala@gmail.com>
Signed-off-by: default avatarJames Hogan <james@albanarts.com>
Signed-off-by: default avatarSean Young <sean@mess.org>
Cc: David Härdeman <david@hardeman.nu>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@s-opensource.com>
parent 3875233d
......@@ -154,6 +154,39 @@ static inline bool is_timing_event(struct ir_raw_event ev)
#define TO_US(duration) DIV_ROUND_CLOSEST((duration), 1000)
#define TO_STR(is_pulse) ((is_pulse) ? "pulse" : "space")
/* functions for IR encoders */
static inline void init_ir_raw_event_duration(struct ir_raw_event *ev,
unsigned int pulse,
u32 duration)
{
init_ir_raw_event(ev);
ev->duration = duration;
ev->pulse = pulse;
}
/**
* struct ir_raw_timings_manchester - Manchester coding timings
* @leader: duration of leader pulse (if any) 0 if continuing
* existing signal (see @pulse_space_start)
* @pulse_space_start: 1 for starting with pulse (0 for starting with space)
* @clock: duration of each pulse/space in ns
* @invert: if set clock logic is inverted
* (0 = space + pulse, 1 = pulse + space)
* @trailer_space: duration of trailer space in ns
*/
struct ir_raw_timings_manchester {
unsigned int leader;
unsigned int pulse_space_start:1;
unsigned int clock;
unsigned int invert:1;
unsigned int trailer_space;
};
int ir_raw_gen_manchester(struct ir_raw_event **ev, unsigned int max,
const struct ir_raw_timings_manchester *timings,
unsigned int n, unsigned int data);
/*
* Routines from rc-raw.c to be used internally and by decoders
*/
......
......@@ -238,6 +238,91 @@ static void ir_raw_disable_protocols(struct rc_dev *dev, u64 protocols)
mutex_unlock(&dev->lock);
}
/**
* ir_raw_gen_manchester() - Encode data with Manchester (bi-phase) modulation.
* @ev: Pointer to pointer to next free event. *@ev is incremented for
* each raw event filled.
* @max: Maximum number of raw events to fill.
* @timings: Manchester modulation timings.
* @n: Number of bits of data.
* @data: Data bits to encode.
*
* Encodes the @n least significant bits of @data using Manchester (bi-phase)
* modulation with the timing characteristics described by @timings, writing up
* to @max raw IR events using the *@ev pointer.
*
* Returns: 0 on success.
* -ENOBUFS if there isn't enough space in the array to fit the
* full encoded data. In this case all @max events will have been
* written.
*/
int ir_raw_gen_manchester(struct ir_raw_event **ev, unsigned int max,
const struct ir_raw_timings_manchester *timings,
unsigned int n, unsigned int data)
{
bool need_pulse;
unsigned int i;
int ret = -ENOBUFS;
i = 1 << (n - 1);
if (timings->leader) {
if (!max--)
return ret;
if (timings->pulse_space_start) {
init_ir_raw_event_duration((*ev)++, 1, timings->leader);
if (!max--)
return ret;
init_ir_raw_event_duration((*ev), 0, timings->leader);
} else {
init_ir_raw_event_duration((*ev), 1, timings->leader);
}
i >>= 1;
} else {
/* continue existing signal */
--(*ev);
}
/* from here on *ev will point to the last event rather than the next */
while (n && i > 0) {
need_pulse = !(data & i);
if (timings->invert)
need_pulse = !need_pulse;
if (need_pulse == !!(*ev)->pulse) {
(*ev)->duration += timings->clock;
} else {
if (!max--)
goto nobufs;
init_ir_raw_event_duration(++(*ev), need_pulse,
timings->clock);
}
if (!max--)
goto nobufs;
init_ir_raw_event_duration(++(*ev), !need_pulse,
timings->clock);
i >>= 1;
}
if (timings->trailer_space) {
if (!(*ev)->pulse)
(*ev)->duration += timings->trailer_space;
else if (!max--)
goto nobufs;
else
init_ir_raw_event_duration(++(*ev), 0,
timings->trailer_space);
}
ret = 0;
nobufs:
/* point to the next event rather than last event before returning */
++(*ev);
return ret;
}
EXPORT_SYMBOL(ir_raw_gen_manchester);
/**
* ir_raw_encode_scancode() - Encode a scancode as raw events
*
......
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