[media] media: rc: add raw decoder for Sharp protocol

Add a raw decoder for the Sharp protocol. It uses a pulse distance
modulation with a pulse of 320us and a bit period of 2ms for a logical 1
and 1ms for a logical 0. The first part of the message consists of a
5-bit address, an 8-bit command, and two other bits, followed by a 40ms
gap before the echo message which is an inverted version of the main
message except for the address bits.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Mauro Carvalho Chehab <m.chehab@samsung.com>
Cc: linux-media@vger.kernel.org
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>

diff --git a/drivers/media/rc/Kconfig b/drivers/media/rc/Kconfig
index 904f11367c2992fc502c4632c5d4a8617cbde839..3b25887a9c09b7a35d7e2ea84f6cd752d4ceb714 100644 (file)
--- a/drivers/media/rc/Kconfig
+++ b/drivers/media/rc/Kconfig
@@ -106,6 +106,15 @@ config IR_SANYO_DECODER
           uses the Sanyo protocol (Sanyo, Aiwa, Chinon remotes),
           and you need software decoding support.
 
+config IR_SHARP_DECODER
+       tristate "Enable IR raw decoder for the Sharp protocol"
+       depends on RC_CORE
+       default y
+
+       ---help---
+          Enable this option if you have an infrared remote control which
+          uses the Sharp protocol, and you need software decoding support.
+
 config IR_MCE_KBD_DECODER
        tristate "Enable IR raw decoder for the MCE keyboard/mouse protocol"
        depends on RC_CORE

diff --git a/drivers/media/rc/Makefile b/drivers/media/rc/Makefile
index f4eb32c0a455e04058bdf52fb2158d1dbe7ac479..36dafed412dd4840f3ec30b336f61aebf6080f86 100644 (file)
--- a/drivers/media/rc/Makefile
+++ b/drivers/media/rc/Makefile
@@ -11,6 +11,7 @@ obj-$(CONFIG_IR_JVC_DECODER) += ir-jvc-decoder.o
 obj-$(CONFIG_IR_SONY_DECODER) += ir-sony-decoder.o
 obj-$(CONFIG_IR_RC5_SZ_DECODER) += ir-rc5-sz-decoder.o
 obj-$(CONFIG_IR_SANYO_DECODER) += ir-sanyo-decoder.o
+obj-$(CONFIG_IR_SHARP_DECODER) += ir-sharp-decoder.o
 obj-$(CONFIG_IR_MCE_KBD_DECODER) += ir-mce_kbd-decoder.o
 obj-$(CONFIG_IR_LIRC_CODEC) += ir-lirc-codec.o
 

diff --git a/drivers/media/rc/ir-sharp-decoder.c b/drivers/media/rc/ir-sharp-decoder.c
new file mode 100644 (file)
index 0000000..4c17be5
--- /dev/null
+++ b/drivers/media/rc/ir-sharp-decoder.c
@@ -0,0 +1,200 @@
+/* ir-sharp-decoder.c - handle Sharp IR Pulse/Space protocol
+ *
+ * Copyright (C) 2013-2014 Imagination Technologies Ltd.
+ *
+ * Based on NEC decoder:
+ * Copyright (C) 2010 by Mauro Carvalho Chehab <mchehab@redhat.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation version 2 of the License.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ */
+
+#include <linux/bitrev.h>
+#include <linux/module.h>
+#include "rc-core-priv.h"
+
+#define SHARP_NBITS            15
+#define SHARP_UNIT             40000  /* ns */
+#define SHARP_BIT_PULSE                (8    * SHARP_UNIT) /* 320us */
+#define SHARP_BIT_0_PERIOD     (25   * SHARP_UNIT) /* 1ms (680us space) */
+#define SHARP_BIT_1_PERIOD     (50   * SHARP_UNIT) /* 2ms (1680ms space) */
+#define SHARP_ECHO_SPACE       (1000 * SHARP_UNIT) /* 40 ms */
+#define SHARP_TRAILER_SPACE    (125  * SHARP_UNIT) /* 5 ms (even longer) */
+
+enum sharp_state {
+       STATE_INACTIVE,
+       STATE_BIT_PULSE,
+       STATE_BIT_SPACE,
+       STATE_TRAILER_PULSE,
+       STATE_ECHO_SPACE,
+       STATE_TRAILER_SPACE,
+};
+
+/**
+ * ir_sharp_decode() - Decode one Sharp pulse or space
+ * @dev:       the struct rc_dev descriptor of the device
+ * @duration:  the struct ir_raw_event descriptor of the pulse/space
+ *
+ * This function returns -EINVAL if the pulse violates the state machine
+ */
+static int ir_sharp_decode(struct rc_dev *dev, struct ir_raw_event ev)
+{
+       struct sharp_dec *data = &dev->raw->sharp;
+       u32 msg, echo, address, command, scancode;
+
+       if (!(dev->enabled_protocols & RC_BIT_SHARP))
+               return 0;
+
+       if (!is_timing_event(ev)) {
+               if (ev.reset)
+                       data->state = STATE_INACTIVE;
+               return 0;
+       }
+
+       IR_dprintk(2, "Sharp decode started at state %d (%uus %s)\n",
+                  data->state, TO_US(ev.duration), TO_STR(ev.pulse));
+
+       switch (data->state) {
+
+       case STATE_INACTIVE:
+               if (!ev.pulse)
+                       break;
+
+               if (!eq_margin(ev.duration, SHARP_BIT_PULSE,
+                              SHARP_BIT_PULSE / 2))
+                       break;
+
+               data->count = 0;
+               data->pulse_len = ev.duration;
+               data->state = STATE_BIT_SPACE;
+               return 0;
+
+       case STATE_BIT_PULSE:
+               if (!ev.pulse)
+                       break;
+
+               if (!eq_margin(ev.duration, SHARP_BIT_PULSE,
+                              SHARP_BIT_PULSE / 2))
+                       break;
+
+               data->pulse_len = ev.duration;
+               data->state = STATE_BIT_SPACE;
+               return 0;
+
+       case STATE_BIT_SPACE:
+               if (ev.pulse)
+                       break;
+
+               data->bits <<= 1;
+               if (eq_margin(data->pulse_len + ev.duration, SHARP_BIT_1_PERIOD,
+                             SHARP_BIT_PULSE * 2))
+                       data->bits |= 1;
+               else if (!eq_margin(data->pulse_len + ev.duration,
+                                   SHARP_BIT_0_PERIOD, SHARP_BIT_PULSE * 2))
+                       break;
+               data->count++;
+
+               if (data->count == SHARP_NBITS ||
+                   data->count == SHARP_NBITS * 2)
+                       data->state = STATE_TRAILER_PULSE;
+               else
+                       data->state = STATE_BIT_PULSE;
+
+               return 0;
+
+       case STATE_TRAILER_PULSE:
+               if (!ev.pulse)
+                       break;
+
+               if (!eq_margin(ev.duration, SHARP_BIT_PULSE,
+                              SHARP_BIT_PULSE / 2))
+                       break;
+
+               if (data->count == SHARP_NBITS) {
+                       /* exp,chk bits should be 1,0 */
+                       if ((data->bits & 0x3) != 0x2)
+                               break;
+                       data->state = STATE_ECHO_SPACE;
+               } else {
+                       data->state = STATE_TRAILER_SPACE;
+               }
+               return 0;
+
+       case STATE_ECHO_SPACE:
+               if (ev.pulse)
+                       break;
+
+               if (!eq_margin(ev.duration, SHARP_ECHO_SPACE,
+                              SHARP_ECHO_SPACE / 4))
+                       break;
+
+               data->state = STATE_BIT_PULSE;
+
+               return 0;
+
+       case STATE_TRAILER_SPACE:
+               if (ev.pulse)
+                       break;
+
+               if (!geq_margin(ev.duration, SHARP_TRAILER_SPACE,
+                               SHARP_BIT_PULSE / 2))
+                       break;
+
+               /* Validate - command, ext, chk should be inverted in 2nd */
+               msg = (data->bits >> 15) & 0x7fff;
+               echo = data->bits & 0x7fff;
+               if ((msg ^ echo) != 0x3ff) {
+                       IR_dprintk(1,
+                                  "Sharp checksum error: received 0x%04x, 0x%04x\n",
+                                  msg, echo);
+                       break;
+               }
+
+               address = bitrev8((msg >> 7) & 0xf8);
+               command = bitrev8((msg >> 2) & 0xff);
+
+               scancode = address << 8 | command;
+               IR_dprintk(1, "Sharp scancode 0x%04x\n", scancode);
+
+               rc_keydown(dev, scancode, 0);
+               data->state = STATE_INACTIVE;
+               return 0;
+       }
+
+       IR_dprintk(1, "Sharp decode failed at count %d state %d (%uus %s)\n",
+                  data->count, data->state, TO_US(ev.duration),
+                  TO_STR(ev.pulse));
+       data->state = STATE_INACTIVE;
+       return -EINVAL;
+}
+
+static struct ir_raw_handler sharp_handler = {
+       .protocols      = RC_BIT_SHARP,
+       .decode         = ir_sharp_decode,
+};
+
+static int __init ir_sharp_decode_init(void)
+{
+       ir_raw_handler_register(&sharp_handler);
+
+       pr_info("IR Sharp protocol handler initialized\n");
+       return 0;
+}
+
+static void __exit ir_sharp_decode_exit(void)
+{
+       ir_raw_handler_unregister(&sharp_handler);
+}
+
+module_init(ir_sharp_decode_init);
+module_exit(ir_sharp_decode_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("James Hogan <james.hogan@imgtec.com>");
+MODULE_DESCRIPTION("Sharp IR protocol decoder");

diff --git a/drivers/media/rc/rc-core-priv.h b/drivers/media/rc/rc-core-priv.h
index 70a180bb0bd090a3b089b58bc7fdc334f89c2c81..c40d6660acac35e3bc0b684141b2e58f076faf0f 100644 (file)
--- a/drivers/media/rc/rc-core-priv.h
+++ b/drivers/media/rc/rc-core-priv.h
@@ -88,6 +88,12 @@ struct ir_raw_event_ctrl {
                unsigned count;
                u64 bits;
        } sanyo;
+       struct sharp_dec {
+               int state;
+               unsigned count;
+               u32 bits;
+               unsigned int pulse_len;
+       } sharp;
        struct mce_kbd_dec {
                struct input_dev *idev;
                struct timer_list rx_timeout;