[media] rc: ir-rc5-decoder: Add encode capability

[linux.git] / drivers / media / rc / ir-rc5-decoder.c

diff --git a/drivers/media/rc/ir-rc5-decoder.c b/drivers/media/rc/ir-rc5-decoder.c
index 84fa6e9b59a1acd9360364fbd30ca0a4e00d3a56..8939ebd7439198161935f573652f25babb438840 100644 (file)
--- a/drivers/media/rc/ir-rc5-decoder.c
+++ b/drivers/media/rc/ir-rc5-decoder.c
@@ -184,9 +184,125 @@ static int ir_rc5_decode(struct rc_dev *dev, struct ir_raw_event ev)
        return -EINVAL;
 }
 
+static struct ir_raw_timings_manchester ir_rc5_timings = {
+       .leader                 = RC5_UNIT,
+       .pulse_space_start      = 0,
+       .clock                  = RC5_UNIT,
+       .trailer_space          = RC5_UNIT * 10,
+};
+
+static struct ir_raw_timings_manchester ir_rc5x_timings[2] = {
+       {
+               .leader                 = RC5_UNIT,
+               .pulse_space_start      = 0,
+               .clock                  = RC5_UNIT,
+               .trailer_space          = RC5X_SPACE,
+       },
+       {
+               .clock                  = RC5_UNIT,
+               .trailer_space          = RC5_UNIT * 10,
+       },
+};
+
+static struct ir_raw_timings_manchester ir_rc5_sz_timings = {
+       .leader                         = RC5_UNIT,
+       .pulse_space_start              = 0,
+       .clock                          = RC5_UNIT,
+       .trailer_space                  = RC5_UNIT * 10,
+};
+
+static int ir_rc5_validate_filter(const struct rc_scancode_filter *scancode,
+                                 unsigned int important_bits)
+{
+       /* all important bits of scancode should be set in mask */
+       if (~scancode->mask & important_bits)
+               return -EINVAL;
+       /* extra bits in mask should be zero in data */
+       if (scancode->mask & scancode->data & ~important_bits)
+               return -EINVAL;
+       return 0;
+}
+
+/**
+ * ir_rc5_encode() - Encode a scancode as a stream of raw events
+ *
+ * @protocols: allowed protocols
+ * @scancode:  scancode filter describing scancode (helps distinguish between
+ *             protocol subtypes when scancode is ambiguous)
+ * @events:    array of raw ir events to write into
+ * @max:       maximum size of @events
+ *
+ * Returns:    The number of events written.
+ *             -ENOBUFS if there isn't enough space in the array to fit the
+ *             encoding. In this case all @max events will have been written.
+ *             -EINVAL if the scancode is ambiguous or invalid.
+ */
+static int ir_rc5_encode(u64 protocols,
+                        const struct rc_scancode_filter *scancode,
+                        struct ir_raw_event *events, unsigned int max)
+{
+       int ret;
+       struct ir_raw_event *e = events;
+       unsigned int data, xdata, command, commandx, system;
+
+       /* Detect protocol and convert scancode to raw data */
+       if (protocols & RC_BIT_RC5 &&
+           !ir_rc5_validate_filter(scancode, 0x1f7f)) {
+               /* decode scancode */
+               command  = (scancode->data & 0x003f) >> 0;
+               commandx = (scancode->data & 0x0040) >> 6;
+               system   = (scancode->data & 0x1f00) >> 8;
+               /* encode data */
+               data = !commandx << 12 | system << 6 | command;
+
+               /* Modulate the data */
+               ret = ir_raw_gen_manchester(&e, max, &ir_rc5_timings, RC5_NBITS,
+                                           data);
+               if (ret < 0)
+                       return ret;
+       } else if (protocols & RC_BIT_RC5X &&
+                  !ir_rc5_validate_filter(scancode, 0x1f7f3f)) {
+               /* decode scancode */
+               xdata    = (scancode->data & 0x00003f) >> 0;
+               command  = (scancode->data & 0x003f00) >> 8;
+               commandx = (scancode->data & 0x004000) >> 14;
+               system   = (scancode->data & 0x1f0000) >> 16;
+               /* commandx and system overlap, bits must match when encoded */
+               if (commandx == (system & 0x1))
+                       return -EINVAL;
+               /* encode data */
+               data = 1 << 18 | system << 12 | command << 6 | xdata;
+
+               /* Modulate the data */
+               ret = ir_raw_gen_manchester(&e, max, &ir_rc5x_timings[0],
+                                       CHECK_RC5X_NBITS,
+                                       data >> (RC5X_NBITS-CHECK_RC5X_NBITS));
+               if (ret < 0)
+                       return ret;
+               ret = ir_raw_gen_manchester(&e, max - (e - events),
+                                       &ir_rc5x_timings[1],
+                                       RC5X_NBITS - CHECK_RC5X_NBITS,
+                                       data);
+               if (ret < 0)
+                       return ret;
+       } else if (protocols & RC_BIT_RC5_SZ &&
+                  !ir_rc5_validate_filter(scancode, 0x2fff)) {
+               /* RC5-SZ scancode is raw enough for Manchester as it is */
+               ret = ir_raw_gen_manchester(&e, max, &ir_rc5_sz_timings,
+                                       RC5_SZ_NBITS, scancode->data & 0x2fff);
+               if (ret < 0)
+                       return ret;
+       } else {
+               return -EINVAL;
+       }
+
+       return e - events;
+}
+
 static struct ir_raw_handler rc5_handler = {
        .protocols      = RC_BIT_RC5 | RC_BIT_RC5X | RC_BIT_RC5_SZ,
        .decode         = ir_rc5_decode,
+       .encode         = ir_rc5_encode,
 };
 
 static int __init ir_rc5_decode_init(void)