Re: [RFC3] Teach drivers/media/IR/ir-raw-event.c to use durations

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On Fri, Apr 9, 2010 at 7:25 AM, Andy Walls <awalls@xxxxxxxxxxxxxxxx> wrote:
> On Thu, 2010-04-08 at 13:39 +0200, David Härdeman wrote:
>> drivers/media/IR/ir-raw-event.c is currently written with the assumption
>> that all "raw" hardware will generate events only on state change (i.e.
>> when a pulse or space starts).
>>
>> However, some hardware (like mceusb, probably the most popular IR receiver
>> out there) only generates duration data (and that data is buffered so using
>> any kind of timing on the data is futile).
>>
>> Furthermore, using signed int's to represent pulse/space durations in ms
>> is a well-known approach to anyone with experience in writing ir decoders.
>>
>> This patch (which has been tested this time) is still a RFC on my proposed
>> interface changes.
>>
>> Changes since last version:
>>
>> o s64's are used to represent pulse/space durations in ns.
>>
>> o Lots of #defines are used in the decoders
>>
>> o Refreshed to apply cleanly on top of Mauro's current git tree
>>
>> o Jon's comments wrt. interrupt-context safe functions have been added
>>
>> Index: ir/drivers/media/IR/ir-raw-event.c
>> ===================================================================
>> --- ir.orig/drivers/media/IR/ir-raw-event.c   2010-04-08 12:30:28.036098192 +0200
>> +++ ir/drivers/media/IR/ir-raw-event.c        2010-04-08 12:45:19.780145403 +0200
>> @@ -15,9 +15,10 @@
>>  #include <media/ir-core.h>
>>  #include <linux/workqueue.h>
>>  #include <linux/spinlock.h>
>> +#include <linux/sched.h>
>>
>> -/* Define the max number of bit transitions per IR keycode */
>> -#define MAX_IR_EVENT_SIZE    256
>> +/* Define the max number of pulse/space transitions to buffer */
>> +#define MAX_IR_EVENT_SIZE      512
>>
>>  /* Used to handle IR raw handler extensions */
>>  static LIST_HEAD(ir_raw_handler_list);
>> @@ -53,19 +54,30 @@
>>  /* Used to load the decoders */
>>  static struct work_struct wq_load;
>>
>> +static void ir_raw_event_work(struct work_struct *work)
>> +{
>> +     s64 d;
>> +     struct ir_raw_event_ctrl *raw =
>> +             container_of(work, struct ir_raw_event_ctrl, rx_work);
>> +
>> +     while (kfifo_out(&raw->kfifo, &d, sizeof(d)) == sizeof(d))
>> +             RUN_DECODER(decode, raw->input_dev, d);
>> +}
>> +
>>  int ir_raw_event_register(struct input_dev *input_dev)
>>  {
>>       struct ir_input_dev *ir = input_get_drvdata(input_dev);
>> -     int rc, size;
>> +     int rc;
>>
>>       ir->raw = kzalloc(sizeof(*ir->raw), GFP_KERNEL);
>>       if (!ir->raw)
>>               return -ENOMEM;
>>
>> -     size = sizeof(struct ir_raw_event) * MAX_IR_EVENT_SIZE * 2;
>> -     size = roundup_pow_of_two(size);
>> +     ir->raw->input_dev = input_dev;
>> +     INIT_WORK(&ir->raw->rx_work, ir_raw_event_work);
>>
>> -     rc = kfifo_alloc(&ir->raw->kfifo, size, GFP_KERNEL);
>> +     rc = kfifo_alloc(&ir->raw->kfifo, sizeof(s64) * MAX_IR_EVENT_SIZE,
>> +                      GFP_KERNEL);
>>       if (rc < 0) {
>>               kfree(ir->raw);
>>               ir->raw = NULL;
>> @@ -90,6 +102,7 @@
>>       if (!ir->raw)
>>               return;
>>
>> +     cancel_work_sync(&ir->raw->rx_work);
>>       RUN_DECODER(raw_unregister, input_dev);
>>
>>       kfifo_free(&ir->raw->kfifo);
>> @@ -97,74 +110,90 @@
>>       ir->raw = NULL;
>>  }
>>
>> -int ir_raw_event_store(struct input_dev *input_dev, enum raw_event_type type)
>> +/**
>> + * ir_raw_event_store() - pass a pulse/space duration to the raw ir decoders
>> + * @input_dev:       the struct input_dev device descriptor
>> + * @duration:        duration of the pulse or space in ns
>> + *
>> + * This routine (which may be called from an interrupt context) stores a
>> + * pulse/space duration for the raw ir decoding state machines. Pulses are
>> + * signalled as positive values and spaces as negative values. A zero value
>> + * will reset the decoding state machines.
>> + */
>> +int ir_raw_event_store(struct input_dev *input_dev, s64 duration)
>>  {
>> -     struct ir_input_dev     *ir = input_get_drvdata(input_dev);
>> -     struct timespec         ts;
>> -     struct ir_raw_event     event;
>> -     int                     rc;
>> +     struct ir_input_dev *ir = input_get_drvdata(input_dev);
>>
>>       if (!ir->raw)
>>               return -EINVAL;
>>
>> -     event.type = type;
>> -     event.delta.tv_sec = 0;
>> -     event.delta.tv_nsec = 0;
>> +     if (kfifo_in(&ir->raw->kfifo, &duration, sizeof(duration)) != sizeof(duration))
>> +             return -ENOMEM;
>>
>> -     ktime_get_ts(&ts);
>> +     return 0;
>> +}
>> +EXPORT_SYMBOL_GPL(ir_raw_event_store);
>>
>> -     if (timespec_equal(&ir->raw->last_event, &event.delta))
>> -             event.type |= IR_START_EVENT;
>> -     else
>> -             event.delta = timespec_sub(ts, ir->raw->last_event);
>> +/**
>> + * ir_raw_event_store_edge() - notify raw ir decoders of the start of a pulse/space
>> + * @input_dev:       the struct input_dev device descriptor
>> + * @type:    the type of the event that has occurred
>> + *
>> + * This routine (which may be called from an interrupt context) is used to
>> + * store the beginning of an ir pulse or space (or the start/end of ir
>> + * reception) for the raw ir decoding state machines. This is used by
>> + * hardware which does not provide durations directly but only interrupts
>> + * (or similar events) on state change.
>> + */
>> +int ir_raw_event_store_edge(struct input_dev *input_dev, enum raw_event_type type)
>> +{
>> +     struct ir_input_dev     *ir = input_get_drvdata(input_dev);
>> +     ktime_t                 now;
>> +     s64                     delta; /* ns */
>> +     int                     rc = 0;
>> +
>> +     if (!ir->raw)
>> +             return -EINVAL;
>>
>> -     memcpy(&ir->raw->last_event, &ts, sizeof(ts));
>> +     now = ktime_get();
>> +     delta = ktime_to_ns(ktime_sub(now, ir->raw->last_event));
>>
>> -     if (event.delta.tv_sec) {
>> -             event.type |= IR_START_EVENT;
>> -             event.delta.tv_sec = 0;
>> -             event.delta.tv_nsec = 0;
>> -     }
>> +     /* Check for a long duration since last event or if we're
>> +      * being called for the first time, note that delta can't
>> +      * possibly be negative.
>> +      */
>> +     if (delta > NSEC_PER_SEC || !ir->raw->last_type)
>> +             type |= IR_START_EVENT;
>>
>> -     kfifo_in(&ir->raw->kfifo, &event, sizeof(event));
>> +     if (type & IR_START_EVENT)
>> +             ir_raw_event_reset(input_dev);
>> +     else if (ir->raw->last_type & IR_SPACE)
>> +             rc = ir_raw_event_store(input_dev, -delta);
>> +     else if (ir->raw->last_type & IR_PULSE)
>> +             rc = ir_raw_event_store(input_dev, delta);
>> +     else
>> +             return 0;
>>
>> +     ir->raw->last_event = now;
>> +     ir->raw->last_type = type;
>>       return rc;
>>  }
>> -EXPORT_SYMBOL_GPL(ir_raw_event_store);
>> +EXPORT_SYMBOL_GPL(ir_raw_event_store_edge);
>>
>> -int ir_raw_event_handle(struct input_dev *input_dev)
>> +/**
>> + * ir_raw_event_handle() - schedules the decoding of stored ir data
>> + * @input_dev:       the struct input_dev device descriptor
>> + *
>> + * This routine will signal the workqueue to start decoding stored ir data.
>> + */
>> +void ir_raw_event_handle(struct input_dev *input_dev)
>>  {
>> -     struct ir_input_dev             *ir = input_get_drvdata(input_dev);
>> -     int                             rc;
>> -     struct ir_raw_event             ev;
>> -     int                             len, i;
>> -
>> -     /*
>> -      * Store the events into a temporary buffer. This allows calling more than
>> -      * one decoder to deal with the received data
>> -      */
>> -     len = kfifo_len(&ir->raw->kfifo) / sizeof(ev);
>> -     if (!len)
>> -             return 0;
>> -
>> -     for (i = 0; i < len; i++) {
>> -             rc = kfifo_out(&ir->raw->kfifo, &ev, sizeof(ev));
>> -             if (rc != sizeof(ev)) {
>> -                     IR_dprintk(1, "overflow error: received %d instead of %zd\n",
>> -                                rc, sizeof(ev));
>> -                     return -EINVAL;
>> -             }
>> -             IR_dprintk(2, "event type %d, time before event: %07luus\n",
>> -                     ev.type, (ev.delta.tv_nsec + 500) / 1000);
>> -             rc = RUN_DECODER(decode, input_dev, &ev);
>> -     }
>> +     struct ir_input_dev *ir = input_get_drvdata(input_dev);
>>
>> -     /*
>> -      * Call all ir decoders. This allows decoding the same event with
>> -      * more than one protocol handler.
>> -      */
>> +     if (!ir->raw)
>> +             return;
>>
>> -     return rc;
>> +     schedule_work(&ir->raw->rx_work);
>>  }
>>  EXPORT_SYMBOL_GPL(ir_raw_event_handle);
>>
>> Index: ir/include/media/ir-core.h
>> ===================================================================
>> --- ir.orig/include/media/ir-core.h   2010-04-08 12:30:28.000000000 +0200
>> +++ ir/include/media/ir-core.h        2010-04-08 13:25:43.761137406 +0200
>> @@ -65,14 +65,12 @@
>>       void                    (*close)(void *priv);
>>  };
>>
>> -struct ir_raw_event {
>> -     struct timespec         delta;  /* Time spent before event */
>> -     enum raw_event_type     type;   /* event type */
>> -};
>> -
>>  struct ir_raw_event_ctrl {
>> -     struct kfifo                    kfifo;          /* fifo for the pulse/space events */
>> -     struct timespec                 last_event;     /* when last event occurred */
>> +     struct work_struct              rx_work;        /* for the rx decoding workqueue */
>> +     struct kfifo                    kfifo;          /* fifo for the pulse/space durations */
>> +     ktime_t                         last_event;     /* when last event occurred */
>> +     enum raw_event_type             last_type;      /* last event type */
>> +     struct input_dev                *input_dev;     /* pointer to the parent input_dev */
>>  };
>>
>>  struct ir_input_dev {
>> @@ -97,8 +95,7 @@
>>  struct ir_raw_handler {
>>       struct list_head list;
>>
>> -     int (*decode)(struct input_dev *input_dev,
>> -                   struct ir_raw_event *ev);
>> +     int (*decode)(struct input_dev *input_dev, s64 duration);
>>       int (*raw_register)(struct input_dev *input_dev);
>>       int (*raw_unregister)(struct input_dev *input_dev);
>>  };
>> @@ -154,8 +151,13 @@
>>  /* Routines from ir-raw-event.c */
>>  int ir_raw_event_register(struct input_dev *input_dev);
>>  void ir_raw_event_unregister(struct input_dev *input_dev);
>> -int ir_raw_event_store(struct input_dev *input_dev, enum raw_event_type type);
>> -int ir_raw_event_handle(struct input_dev *input_dev);
>> +void ir_raw_event_handle(struct input_dev *input_dev);
>> +int ir_raw_event_store(struct input_dev *input_dev, s64 duration);
>> +int ir_raw_event_store_edge(struct input_dev *input_dev, enum raw_event_type type);
>> +static inline void ir_raw_event_reset(struct input_dev *input_dev) {
>> +     ir_raw_event_store(input_dev, 0);
>> +     ir_raw_event_handle(input_dev);
>> +}
>>  int ir_raw_handler_register(struct ir_raw_handler *ir_raw_handler);
>>  void ir_raw_handler_unregister(struct ir_raw_handler *ir_raw_handler);
>>  void ir_raw_init(void);
>> @@ -174,4 +176,26 @@
>>  #define load_rc5_decode()    0
>>  #endif
>>
>> +/* macros for ir decoders */
>> +#define PULSE(units)                         ((units))
>> +#define SPACE(units)                         (-(units))
>
> Encoding pulse vs space with a negative sign, even if now hidden with
> macros, is still just using a sign instead of a boolean.  Memory in
> modern computers (and now microcontrollers) is cheap and only getting
> cheaper.  Don't give up readability, flexibility, or mainatainability,
> for the sake of saving memory.

I agree with this. I did it with signed ints in my first version, then
ripped it out and switched to duration + boolean. The duration/boolean
pair was much easier to understand. This is a matter of style, both
schemes work.

>
>
>
>> +#define IS_RESET(duration)                   ((duration) == 0)
>> +#define IS_PULSE(duration)                   ((duration) > 0)
>> +#define IS_SPACE(duration)                   ((duration) < 0)
>> +#define DURATION(duration)                   (abs((duration)))
>> +#define IS_TRANSITION(x ,y)                  ((x) * (y) < 0)
>> +#define DECREASE_DURATION(duration, amount)                  \
>> +     do {                                                    \
>> +             if (IS_SPACE(duration))                         \
>> +                     duration += (amount);                   \
>> +             else if (IS_PULSE(duration))                    \
>> +                     duration -= (amount);                   \
>> +     } while(0)
>> +
>> +#define TO_UNITS(duration, unit_len)                         \
>> +     ((int)((duration) > 0 ?                                 \
>> +             DIV_ROUND_CLOSEST(abs((duration)), (unit_len)) :\
>> +             - DIV_ROUND_CLOSEST(abs((duration)), (unit_len))))
>> +#define TO_US(duration)              ((int)TO_UNITS(duration, 1000))
>> +
>>  #endif /* _IR_CORE */
>> Index: ir/drivers/media/IR/ir-nec-decoder.c
>> ===================================================================
>> --- ir.orig/drivers/media/IR/ir-nec-decoder.c 2010-04-08 12:30:28.000000000 +0200
>> +++ ir/drivers/media/IR/ir-nec-decoder.c      2010-04-08 12:35:02.276484204 +0200
>> @@ -13,15 +13,16 @@
>>   */
>>
>>  #include <media/ir-core.h>
>> +#include <linux/bitrev.h>
>>
>>  #define NEC_NBITS            32
>> -#define NEC_UNIT             559979 /* ns */
>> -#define NEC_HEADER_MARK              (16 * NEC_UNIT)
>> -#define NEC_HEADER_SPACE     (8 * NEC_UNIT)
>> -#define NEC_REPEAT_SPACE     (4 * NEC_UNIT)
>> -#define NEC_MARK             (NEC_UNIT)
>> -#define NEC_0_SPACE          (NEC_UNIT)
>> -#define NEC_1_SPACE          (3 * NEC_UNIT)
>> +#define NEC_UNIT             562500  /* ns */
>
> Have you got a spec on the NEC protocol that justifies 562.5 usec?
>
> >From the best I can tell from the sources I have read and some deductive
> reasoning, 560 usec is the actual number.  Here's one:
>
>        http://www.audiodevelopers.com/temp/Remote_Controls.ppt
>
> Note:
>        560 usec * 38 kHz ~= 4192/197

In the PPT you reference there are three numbers...
http://www.sbprojects.com/knowledge/ir/nec.htm

560us
1.12ms
2.25ms

I think those are rounding errors.

562.5 * 2 = 1.125ms * 2 = 2.25ms

Most IR protocols are related in a power of two pattern for their
timings to make them easy to decode.

The protocol doesn't appear to be based on an even number of 38Khz cycles.
These are easy things to change as we get better data on the protocols.

>
> and that the three numbers that yield ~560 usec don't evenly divide each
> other:
>
>        $ factor 4192 197 38000
>        4192: 2 2 2 2 2 131
>        197: 197
>        38000: 2 2 2 2 5 5 5 19
>
> which strikes me as being done on purpose (maybe only by me?).
>
> Also note that:
>
>        4192 / 38 kHz = 110.32 usec
>
> and public sources list 110 usec as the NEC repeat period.
>
>
>> +#define NEC_HEADER_PULSE     PULSE(16)
>> +#define NEC_HEADER_SPACE     SPACE(8)
>> +#define NEC_REPEAT_SPACE     SPACE(4)
>> +#define NEC_BIT_PULSE                PULSE(1)
>> +#define NEC_BIT_0_SPACE              SPACE(1)
>> +#define NEC_BIT_1_SPACE              SPACE(3)
>
> This is slightly better than your previous patch, but the original
> #defines were still clearer.  A maintainer coming through has to spend
> time and energy on asking "16 what?" for example.
>
>
> While I'm on the subject of maintainability:
> It would be better to convert #defines into "const int"s within a
> function scope, if these defines are only used in one function and file
> scope is unneeded.
>
>
>
>>  /* Used to register nec_decoder clients */
>>  static LIST_HEAD(decoder_list);
>> @@ -29,21 +30,13 @@
>>
>>  enum nec_state {
>>       STATE_INACTIVE,
>> -     STATE_HEADER_MARK,
>>       STATE_HEADER_SPACE,
>> -     STATE_MARK,
>> -     STATE_SPACE,
>> -     STATE_TRAILER_MARK,
>> +     STATE_BIT_PULSE,
>> +     STATE_BIT_SPACE,
>> +     STATE_TRAILER_PULSE,
>>       STATE_TRAILER_SPACE,
>>  };
>>
>> -struct nec_code {
>> -     u8      address;
>> -     u8      not_address;
>> -     u8      command;
>> -     u8      not_command;
>> -};
>> -
>>  struct decoder_data {
>>       struct list_head        list;
>>       struct ir_input_dev     *ir_dev;
>> @@ -51,7 +44,7 @@
>>
>>       /* State machine control */
>>       enum nec_state          state;
>> -     struct nec_code         nec_code;
>> +     u32                     nec_bits;
>>       unsigned                count;
>>  };
>>
>> @@ -62,7 +55,6 @@
>>   *
>>   * Returns the struct decoder_data that corresponds to a device
>>   */
>> -
>>  static struct decoder_data *get_decoder_data(struct  ir_input_dev *ir_dev)
>>  {
>>       struct decoder_data *data = NULL;
>> @@ -123,20 +115,20 @@
>>       .attrs  = decoder_attributes,
>>  };
>>
>> -
>>  /**
>>   * ir_nec_decode() - Decode one NEC pulse or space
>>   * @input_dev:       the struct input_dev descriptor of the device
>> - * @ev:              event array with type/duration of pulse/space
>> + * @duration:        duration in ns of pulse/space
>>   *
>>   * This function returns -EINVAL if the pulse violates the state machine
>>   */
>> -static int ir_nec_decode(struct input_dev *input_dev,
>> -                      struct ir_raw_event *ev)
>> +static int ir_nec_decode(struct input_dev *input_dev, s64 duration)
>>  {
>>       struct decoder_data *data;
>>       struct ir_input_dev *ir_dev = input_get_drvdata(input_dev);
>> -     int bit, last_bit;
>> +     int u;
>> +     u32 scancode;
>> +     u8 address, not_address, command, not_command;
>>
>>       data = get_decoder_data(ir_dev);
>>       if (!data)
>> @@ -145,150 +137,107 @@
>>       if (!data->enabled)
>>               return 0;
>>
>> -     /* Except for the initial event, what matters is the previous bit */
>> -     bit = (ev->type & IR_PULSE) ? 1 : 0;
>> -
>> -     last_bit = !bit;
>> -
>> -     /* Discards spurious space last_bits when inactive */
>> -
>> -     /* Very long delays are considered as start events */
>> -     if (ev->delta.tv_nsec > NEC_HEADER_MARK + NEC_HEADER_SPACE - NEC_UNIT / 2)
>                                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>                                        (example compile-time constant)
>> +     if (IS_RESET(duration)) {
>>               data->state = STATE_INACTIVE;
>> +             return 0;
>> +     }
>>
>> -     if (ev->type & IR_START_EVENT)
>> -             data->state = STATE_INACTIVE;
>> +     u = TO_UNITS(duration, NEC_UNIT);
>              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>
> Why are 2 run-time divisons and 2 run-time abs() invocations for every
> measurment preferrable to comparisons to compile-time constants?
>
> Your TO_UNITS(), IS_SPACE(), etc. macros help with the readability and
> maintainability over your previously proposed change, but you're still
> having the CPU do extra work over what was done before.
>
> Regards,
> Andy
>
>> +     if (DURATION(u) == 0)
>> +             goto out;
>> +
>> +     IR_dprintk(2, "NEC decode started at state %d (%i units, %ius)\n",
>> +                data->state, u, TO_US(duration));
>>
>>       switch (data->state) {
>> -     case STATE_INACTIVE:
>> -             if (!bit)               /* PULSE marks the start event */
>> -                     return 0;
>>
>> -             data->count = 0;
>> -             data->state = STATE_HEADER_MARK;
>> -             memset (&data->nec_code, 0, sizeof(data->nec_code));
>> -             return 0;
>> -     case STATE_HEADER_MARK:
>> -             if (!last_bit)
>> -                     goto err;
>> -             if (ev->delta.tv_nsec < NEC_HEADER_MARK - 6 * NEC_UNIT)
>> -                     goto err;
>> -             data->state = STATE_HEADER_SPACE;
>> +     case STATE_INACTIVE:
>> +             if (u == NEC_HEADER_PULSE) {
>> +                     data->count = 0;
>> +                     data->state = STATE_HEADER_SPACE;
>> +             }
>>               return 0;
>> +
>>       case STATE_HEADER_SPACE:
>> -             if (last_bit)
>> -                     goto err;
>> -             if (ev->delta.tv_nsec >= NEC_HEADER_SPACE - NEC_UNIT / 2) {
>> -                     data->state = STATE_MARK;
>> +             if (u == NEC_HEADER_SPACE) {
>> +                     data->state = STATE_BIT_PULSE;
>>                       return 0;
>> -             }
>> -
>> -             if (ev->delta.tv_nsec >= NEC_REPEAT_SPACE - NEC_UNIT / 2) {
>> +             } else if (u == NEC_REPEAT_SPACE) {
>>                       ir_repeat(input_dev);
>>                       IR_dprintk(1, "Repeat last key\n");
>> -                     data->state = STATE_TRAILER_MARK;
>> +                     data->state = STATE_TRAILER_PULSE;
>>                       return 0;
>>               }
>> -             goto err;
>> -     case STATE_MARK:
>> -             if (!last_bit)
>> -                     goto err;
>> -             if ((ev->delta.tv_nsec > NEC_MARK + NEC_UNIT / 2) ||
>> -                 (ev->delta.tv_nsec < NEC_MARK - NEC_UNIT / 2))
>> -                     goto err;
>> -             data->state = STATE_SPACE;
>> -             return 0;
>> -     case STATE_SPACE:
>> -             if (last_bit)
>> -                     goto err;
>> -
>> -             if ((ev->delta.tv_nsec >= NEC_0_SPACE - NEC_UNIT / 2) &&
>> -                 (ev->delta.tv_nsec < NEC_0_SPACE + NEC_UNIT / 2))
>> -                     bit = 0;
>> -             else if ((ev->delta.tv_nsec >= NEC_1_SPACE - NEC_UNIT / 2) &&
>> -                      (ev->delta.tv_nsec < NEC_1_SPACE + NEC_UNIT / 2))
>> -                     bit = 1;
>> -             else {
>> -                     IR_dprintk(1, "Decode failed at %d-th bit (%s) @%luus\n",
>> -                             data->count,
>> -                             last_bit ? "pulse" : "space",
>> -                             (ev->delta.tv_nsec + 500) / 1000);
>> +             break;
>> +
>> +     case STATE_BIT_PULSE:
>> +             if (u == NEC_BIT_PULSE) {
>> +                     data->state = STATE_BIT_SPACE;
>> +                     return 0;
>> +             }
>> +             break;
>> +
>> +     case STATE_BIT_SPACE:
>> +             if (u != NEC_BIT_0_SPACE && u != NEC_BIT_1_SPACE)
>> +                     break;
>>
>> -                     goto err2;
>> +             data->nec_bits <<= 1;
>> +             if (u == NEC_BIT_1_SPACE)
>> +                     data->nec_bits |= 1;
>> +             data->count++;
>> +
>> +             if (data->count != NEC_NBITS) {
>> +                     data->state = STATE_BIT_PULSE;
>> +                     return 0;
>>               }
>>
>> -             /* Ok, we've got a valid bit. proccess it */
>> -             if (bit) {
>> -                     int shift = data->count;
>> -
>> -                     /*
>> -                      * NEC transmit bytes on this temporal order:
>> -                      * address | not address | command | not command
>> -                      */
>> -                     if (shift < 8) {
>> -                             data->nec_code.address |= 1 << shift;
>> -                     } else if (shift < 16) {
>> -                             data->nec_code.not_address |= 1 << (shift - 8);
>> -                     } else if (shift < 24) {
>> -                             data->nec_code.command |= 1 << (shift - 16);
>> -                     } else {
>> -                             data->nec_code.not_command |= 1 << (shift - 24);
>> -                     }
>> +             address     = bitrev8((data->nec_bits >> 24) & 0xff);
>> +             not_address = bitrev8((data->nec_bits >> 16) & 0xff);
>> +             command     = bitrev8((data->nec_bits >>  8) & 0xff);
>> +             not_command = bitrev8((data->nec_bits >>  0) & 0xff);
>> +
>> +             if ((command ^ not_command) != 0xff) {
>> +                     IR_dprintk(1, "NEC checksum error: received 0x%08x\n",
>> +                                data->nec_bits);
>> +                     break;
>>               }
>> -             if (++data->count == NEC_NBITS) {
>> -                     u32 scancode;
>> -                     /*
>> -                      * Fixme: may need to accept Extended NEC protocol?
>> -                      */
>> -                     if ((data->nec_code.command ^ data->nec_code.not_command) != 0xff)
>> -                             goto checksum_err;
>> -
>> -                     if ((data->nec_code.address ^ data->nec_code.not_address) != 0xff) {
>> -                             /* Extended NEC */
>> -                             scancode = data->nec_code.address << 16 |
>> -                                        data->nec_code.not_address << 8 |
>> -                                        data->nec_code.command;
>> -                             IR_dprintk(1, "NEC scancode 0x%06x\n", scancode);
>> -                     } else {
>> -                             /* normal NEC */
>> -                             scancode = data->nec_code.address << 8 |
>> -                                        data->nec_code.command;
>> -                             IR_dprintk(1, "NEC scancode 0x%04x\n", scancode);
>> -                     }
>> -                     ir_keydown(input_dev, scancode, 0);
>> -
>> -                     data->state = STATE_TRAILER_MARK;
>> -             } else
>> -                     data->state = STATE_MARK;
>> -             return 0;
>> -     case STATE_TRAILER_MARK:
>> -             if (!last_bit)
>> -                     goto err;
>> -             data->state = STATE_TRAILER_SPACE;
>> +
>> +             if ((address ^ not_address) != 0xff) {
>> +                     /* Extended NEC */
>> +                     scancode = address     << 16 |
>> +                                not_address <<  8 |
>> +                                command;
>> +                     IR_dprintk(1, "NEC (Ext) scancode 0x%06x\n", scancode);
>> +             } else {
>> +                     /* normal NEC */
>> +                     scancode = address << 8 | command;
>> +                     IR_dprintk(1, "NEC scancode 0x%04x\n", scancode);
>> +             }
>> +
>> +             ir_keydown(input_dev, scancode, 0);
>> +             data->state = STATE_TRAILER_PULSE;
>>               return 0;
>> +
>> +     case STATE_TRAILER_PULSE:
>> +             if (u > 0) {
>> +                     data->state = STATE_TRAILER_SPACE;
>> +                     return 0;
>> +             }
>> +             break;
>> +
>>       case STATE_TRAILER_SPACE:
>> -             if (last_bit)
>> -                     goto err;
>> -             data->state = STATE_INACTIVE;
>> -             return 0;
>> -     }
>> +             if (u < 0) {
>> +                     data->state = STATE_INACTIVE;
>> +                     return 0;
>> +             }
>>
>> -err:
>> -     IR_dprintk(1, "NEC decoded failed at state %d (%s) @ %luus\n",
>> -                data->state,
>> -                bit ? "pulse" : "space",
>> -                (ev->delta.tv_nsec + 500) / 1000);
>> -err2:
>> -     data->state = STATE_INACTIVE;
>> -     return -EINVAL;
>> +             break;
>> +     }
>>
>> -checksum_err:
>> +out:
>> +     IR_dprintk(1, "NEC decode failed at state %d (%i units, %ius)\n",
>> +                data->state, u, TO_US(duration));
>>       data->state = STATE_INACTIVE;
>> -     IR_dprintk(1, "NEC checksum error: received 0x%02x%02x%02x%02x\n",
>> -                data->nec_code.address,
>> -                data->nec_code.not_address,
>> -                data->nec_code.command,
>> -                data->nec_code.not_command);
>>       return -EINVAL;
>>  }
>>
>> Index: ir/drivers/media/IR/ir-rc5-decoder.c
>> ===================================================================
>> --- ir.orig/drivers/media/IR/ir-rc5-decoder.c 2010-04-08 12:30:28.000000000 +0200
>> +++ ir/drivers/media/IR/ir-rc5-decoder.c      2010-04-08 12:48:28.361137494 +0200
>> @@ -21,11 +21,8 @@
>>
>>  #include <media/ir-core.h>
>>
>> -static unsigned int ir_rc5_remote_gap = 888888;
>> -
>>  #define RC5_NBITS            14
>> -#define RC5_BIT                      (ir_rc5_remote_gap * 2)
>> -#define RC5_DURATION         (ir_rc5_remote_gap * RC5_NBITS)
>> +#define RC5_UNIT             888888 /* ns */
>>
>>  /* Used to register rc5_decoder clients */
>>  static LIST_HEAD(decoder_list);
>> @@ -33,13 +30,9 @@
>>
>>  enum rc5_state {
>>       STATE_INACTIVE,
>> -     STATE_MARKSPACE,
>> -     STATE_TRAILER,
>> -};
>> -
>> -struct rc5_code {
>> -     u8      address;
>> -     u8      command;
>> +     STATE_BIT_START,
>> +     STATE_BIT_END,
>> +     STATE_FINISHED,
>>  };
>>
>>  struct decoder_data {
>> @@ -49,8 +42,9 @@
>>
>>       /* State machine control */
>>       enum rc5_state          state;
>> -     struct rc5_code         rc5_code;
>> -     unsigned                code, elapsed, last_bit, last_code;
>> +     u32                     rc5_bits;
>> +     int                     last_unit;
>> +     unsigned                count;
>>  };
>>
>>
>> @@ -122,18 +116,19 @@
>>  };
>>
>>  /**
>> - * handle_event() - Decode one RC-5 pulse or space
>> + * ir_rc5_decode() - Decode one RC-5 pulse or space
>>   * @input_dev:       the struct input_dev descriptor of the device
>> - * @ev:              event array with type/duration of pulse/space
>> + * @duration:        duration of pulse/space in ns
>>   *
>>   * This function returns -EINVAL if the pulse violates the state machine
>>   */
>> -static int ir_rc5_decode(struct input_dev *input_dev,
>> -                     struct ir_raw_event *ev)
>> +static int ir_rc5_decode(struct input_dev *input_dev, s64 duration)
>>  {
>>       struct decoder_data *data;
>>       struct ir_input_dev *ir_dev = input_get_drvdata(input_dev);
>> -     int is_pulse, scancode, delta, toggle;
>> +     u8 command, system, toggle;
>> +     u32 scancode;
>> +     int u;
>>
>>       data = get_decoder_data(ir_dev);
>>       if (!data)
>> @@ -142,79 +137,84 @@
>>       if (!data->enabled)
>>               return 0;
>>
>> -     delta = DIV_ROUND_CLOSEST(ev->delta.tv_nsec, ir_rc5_remote_gap);
>> -
>> -     /* 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 (delta > RC5_DURATION || (ev->type & IR_START_EVENT))
>> +     if (IS_RESET(duration)) {
>>               data->state = STATE_INACTIVE;
>> -
>> -     switch (data->state) {
>> -     case STATE_INACTIVE:
>> -     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 (!is_pulse)
>> -                     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:
>> -             if (delta != 1)
>> -                     data->last_bit = data->last_bit ? 0 : 1;
>> +     }
>>
>> -             data->elapsed += delta;
>> +     u = TO_UNITS(duration, RC5_UNIT);
>> +     if (DURATION(u) == 0)
>> +             goto out;
>> +
>> +again:
>> +     IR_dprintk(2, "RC5 decode started at state %i (%i units, %ius)\n",
>> +                data->state, u, TO_US(duration));
>>
>> -             if ((data->elapsed % 2) == 1)
>> -                     return 0;
>> +     if (DURATION(u) == 0 && data->state != STATE_FINISHED)
>> +             return 0;
>> +
>> +     switch (data->state) {
>>
>> -             data->code <<= 1;
>> -             data->code |= data->last_bit;
>> +     case STATE_INACTIVE:
>> +             if (IS_PULSE(u)) {
>> +                     data->state = STATE_BIT_START;
>> +                     data->count = 1;
>> +                     DECREASE_DURATION(u, 1);
>> +                     goto again;
>> +             }
>> +             break;
>>
>> -             /* Fill the 2 unused bits at the command with 0 */
>> -             if (data->elapsed / 2 == 6)
>> -                     data->code <<= 2;
>> -
>> -             if (data->elapsed >= (RC5_NBITS - 1) * 2) {
>> -                     scancode = data->code;
>> -
>> -                     /* 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;
>> +     case STATE_BIT_START:
>> +             if (DURATION(u) == 1) {
>> +                     data->rc5_bits <<= 1;
>> +                     if (IS_SPACE(u))
>> +                             data->rc5_bits |= 1;
>> +                     data->count++;
>> +                     data->last_unit = u;
>> +
>> +                     /*
>> +                      * If the last bit is zero, a space will merge
>> +                      * with the silence after the command.
>> +                      */
>> +                     if (IS_PULSE(u) && data->count == RC5_NBITS) {
>> +                             data->state = STATE_FINISHED;
>> +                             goto again;
>>                       }
>>
>> -                     toggle = (scancode & 0x2000) ? 1 : 0;
>> +                     data->state = STATE_BIT_END;
>> +                     return 0;
>> +             }
>> +             break;
>>
>> -                     if (scancode == data->last_code) {
>> -                             IR_dprintk(1, "RC-5 repeat\n");
>> -                             ir_repeat(input_dev);
>> -                     } else {
>> -                             data->last_code = scancode;
>> -                             scancode &= 0x1fff;
>> -                             IR_dprintk(1, "RC-5 scancode 0x%04x\n", scancode);
>> +     case STATE_BIT_END:
>> +             if (IS_TRANSITION(u, data->last_unit)) {
>> +                     if (data->count == RC5_NBITS)
>> +                             data->state = STATE_FINISHED;
>> +                     else
>> +                             data->state = STATE_BIT_START;
>>
>> -                             ir_keydown(input_dev, scancode, 0);
>> -                     }
>> -                     data->state = STATE_TRAILER;
>> +                     DECREASE_DURATION(u, 1);
>> +                     goto again;
>>               }
>> -             return 0;
>> -     case STATE_TRAILER:
>> +             break;
>> +
>> +     case STATE_FINISHED:
>> +             command  = (data->rc5_bits & 0x0003F) >> 0;
>> +             system   = (data->rc5_bits & 0x007C0) >> 6;
>> +             toggle   = (data->rc5_bits & 0x00800) ? 1 : 0;
>> +             command += (data->rc5_bits & 0x01000) ? 0 : 0x40;
>> +             scancode = system << 8 | command;
>> +
>> +             IR_dprintk(1, "RC5 scancode 0x%04x (toggle: %u)\n",
>> +                        scancode, toggle);
>> +             ir_keydown(input_dev, scancode, toggle);
>>               data->state = STATE_INACTIVE;
>>               return 0;
>>       }
>>
>> -err:
>> -     IR_dprintk(1, "RC-5 decoded failed at %s @ %luus\n",
>> -                is_pulse ? "pulse" : "space",
>> -                (ev->delta.tv_nsec + 500) / 1000);
>> +out:
>> +     IR_dprintk(1, "RC5 decode failed at state %i (%i units, %ius)\n",
>> +                data->state, u, TO_US(duration));
>>       data->state = STATE_INACTIVE;
>>       return -EINVAL;
>>  }
>> Index: ir/drivers/media/video/saa7134/saa7134-input.c
>> ===================================================================
>> --- ir.orig/drivers/media/video/saa7134/saa7134-input.c       2010-04-08 12:30:28.000000000 +0200
>> +++ ir/drivers/media/video/saa7134/saa7134-input.c    2010-04-08 12:31:07.697096148 +0200
>> @@ -1018,7 +1018,7 @@
>>       saa_clearb(SAA7134_GPIO_GPMODE3, SAA7134_GPIO_GPRESCAN);
>>       saa_setb(SAA7134_GPIO_GPMODE3, SAA7134_GPIO_GPRESCAN);
>>       space = saa_readl(SAA7134_GPIO_GPSTATUS0 >> 2) & ir->mask_keydown;
>> -     ir_raw_event_store(dev->remote->dev, space ? IR_SPACE : IR_PULSE);
>> +     ir_raw_event_store_edge(dev->remote->dev, space ? IR_SPACE : IR_PULSE);
>>
>>
>>       /*
>>
>
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-- 
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