V4L/DVB: Add RC6 support to ir-core

This patch adds an RC6 decoder (modes 0 and 6A) to ir-core.

Signed-off-by: David Härdeman <david@hardeman.nu>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

6 files changed, 432 insertions, 0 deletions

diff --git a/drivers/media/IR/Kconfig b/drivers/media/IR/Kconfig
index ba81bda3513d..28d336d98187 100644
--- a/drivers/media/IR/Kconfig
+++ b/drivers/media/IR/Kconfig
@@ -27,3 +27,12 @@ config IR_RC5_DECODER
         ---help---
            Enable this option if you have IR with RC-5 protocol, and
            if the IR is decoded in software
+
+config IR_RC6_DECODER
+        tristate "Enable IR raw decoder for the RC6 protocol"
+        depends on IR_CORE
+        default y
+
+        ---help---
+           Enable this option if you have an infrared remote control which
+           uses the RC6 protocol, and you need software decoding support.
diff --git a/drivers/media/IR/Makefile b/drivers/media/IR/Makefile
index 62e12d5c443a..792d9cad7efc 100644
--- a/drivers/media/IR/Makefile
+++ b/drivers/media/IR/Makefile
@@ -7,3 +7,4 @@ obj-$(CONFIG_IR_CORE) += ir-core.o
 obj-$(CONFIG_VIDEO_IR) += ir-common.o
 obj-$(CONFIG_IR_NEC_DECODER) += ir-nec-decoder.o
 obj-$(CONFIG_IR_RC5_DECODER) += ir-rc5-decoder.o
+obj-$(CONFIG_IR_RC6_DECODER) += ir-rc6-decoder.o
diff --git a/drivers/media/IR/ir-core-priv.h b/drivers/media/IR/ir-core-priv.h
index ea546659e4ce..59d5ed7e103e 100644
--- a/drivers/media/IR/ir-core-priv.h
+++ b/drivers/media/IR/ir-core-priv.h
@@ -108,4 +108,11 @@ void ir_raw_init(void);
 #define load_rc5_decode()       0
 #endif
 
+/* from ir-rc6-decoder.c */
+#ifdef CONFIG_IR_RC5_DECODER_MODULE
+#define load_rc6_decode()       request_module("ir-rc6-decoder")
+#else
+#define load_rc6_decode()       0
+#endif
+
 #endif /* _IR_RAW_EVENT */
diff --git a/drivers/media/IR/ir-raw-event.c b/drivers/media/IR/ir-raw-event.c
index b49d01256be3..674442b2f0a8 100644
--- a/drivers/media/IR/ir-raw-event.c
+++ b/drivers/media/IR/ir-raw-event.c
@@ -226,6 +226,7 @@ static void init_decoders(struct work_struct *work)
 
         load_nec_decode();
         load_rc5_decode();
+        load_rc6_decode();
 
         /* If needed, we may later add some init code. In this case,
            it is needed to change the CONFIG_MODULE test at ir-core.h
diff --git a/drivers/media/IR/ir-rc6-decoder.c b/drivers/media/IR/ir-rc6-decoder.c
new file mode 100644
index 000000000000..ccc5be240f82
--- /dev/null
+++ b/drivers/media/IR/ir-rc6-decoder.c
@@ -0,0 +1,412 @@
+/* ir-rc6-decoder.c - A decoder for the RC6 IR protocol
+ *
+ * Copyright (C) 2010 by David Härdeman <david@hardeman.nu>
+ *
+ * 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 "ir-core-priv.h"
+
+/*
+ * This decoder currently supports:
+ * RC6-0-16     (standard toggle bit in header)
+ * RC6-6A-24    (no toggle bit)
+ * RC6-6A-32    (MCE version with toggle bit in body)
+ */
+
+#define RC6_UNIT                444444  /* us */
+#define RC6_HEADER_NBITS        4       /* not including toggle bit */
+#define RC6_0_NBITS             16
+#define RC6_6A_SMALL_NBITS      24
+#define RC6_6A_LARGE_NBITS      32
+#define RC6_PREFIX_PULSE        PULSE(6)
+#define RC6_PREFIX_SPACE        SPACE(2)
+#define RC6_MODE_MASK           0x07    /* for the header bits */
+#define RC6_STARTBIT_MASK       0x08    /* for the header bits */
+#define RC6_6A_MCE_TOGGLE_MASK  0x8000  /* for the body bits */
+
+/* Used to register rc6_decoder clients */
+static LIST_HEAD(decoder_list);
+static DEFINE_SPINLOCK(decoder_lock);
+
+enum rc6_mode {
+        RC6_MODE_0,
+        RC6_MODE_6A,
+        RC6_MODE_UNKNOWN,
+};
+
+enum rc6_state {
+        STATE_INACTIVE,
+        STATE_PREFIX_SPACE,
+        STATE_HEADER_BIT_START,
+        STATE_HEADER_BIT_END,
+        STATE_TOGGLE_START,
+        STATE_TOGGLE_END,
+        STATE_BODY_BIT_START,
+        STATE_BODY_BIT_END,
+        STATE_FINISHED,
+};
+
+struct decoder_data {
+        struct list_head        list;
+        struct ir_input_dev     *ir_dev;
+        int                     enabled:1;
+
+        /* State machine control */
+        enum rc6_state          state;
+        u8                      header;
+        u32                     body;
+        int                     last_unit;
+        bool                    toggle;
+        unsigned                count;
+        unsigned                wanted_bits;
+};
+
+
+/**
+ * get_decoder_data()   - gets decoder data
+ * @input_dev:  input device
+ *
+ * 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;
+
+        spin_lock(&decoder_lock);
+        list_for_each_entry(data, &decoder_list, list) {
+                if (data->ir_dev == ir_dev)
+                        break;
+        }
+        spin_unlock(&decoder_lock);
+        return data;
+}
+
+static ssize_t store_enabled(struct device *d,
+                             struct device_attribute *mattr,
+                             const char *buf,
+                             size_t len)
+{
+        unsigned long value;
+        struct ir_input_dev *ir_dev = dev_get_drvdata(d);
+        struct decoder_data *data = get_decoder_data(ir_dev);
+
+        if (!data)
+                return -EINVAL;
+
+        if (strict_strtoul(buf, 10, &value) || value > 1)
+                return -EINVAL;
+
+        data->enabled = value;
+
+        return len;
+}
+
+static ssize_t show_enabled(struct device *d,
+                             struct device_attribute *mattr, char *buf)
+{
+        struct ir_input_dev *ir_dev = dev_get_drvdata(d);
+        struct decoder_data *data = get_decoder_data(ir_dev);
+
+        if (!data)
+                return -EINVAL;
+
+        if (data->enabled)
+                return sprintf(buf, "1\n");
+        else
+        return sprintf(buf, "0\n");
+}
+
+static DEVICE_ATTR(enabled, S_IRUGO | S_IWUSR, show_enabled, store_enabled);
+
+static struct attribute *decoder_attributes[] = {
+        &dev_attr_enabled.attr,
+        NULL
+};
+
+static struct attribute_group decoder_attribute_group = {
+        .name   = "rc6_decoder",
+        .attrs  = decoder_attributes,
+};
+
+static enum rc6_mode rc6_mode(struct decoder_data *data) {
+        switch (data->header & RC6_MODE_MASK) {
+        case 0:
+                return RC6_MODE_0;
+        case 6:
+                if (!data->toggle)
+                        return RC6_MODE_6A;
+                /* fall through */
+        default:
+                return RC6_MODE_UNKNOWN;
+        }
+}
+
+/**
+ * ir_rc6_decode() - Decode one RC6 pulse or space
+ * @input_dev:  the struct input_dev descriptor of the device
+ * @duration:   duration of pulse/space in ns
+ *
+ * This function returns -EINVAL if the pulse violates the state machine
+ */
+static int ir_rc6_decode(struct input_dev *input_dev, s64 duration)
+{
+        struct decoder_data *data;
+        struct ir_input_dev *ir_dev = input_get_drvdata(input_dev);
+        u32 scancode;
+        u8 toggle;
+        int u;
+
+        data = get_decoder_data(ir_dev);
+        if (!data)
+                return -EINVAL;
+
+        if (!data->enabled)
+                return 0;
+
+        if (IS_RESET(duration)) {
+                data->state = STATE_INACTIVE;
+                return 0;
+        }
+
+        u =  TO_UNITS(duration, RC6_UNIT);
+        if (DURATION(u) == 0)
+                goto out;
+
+again:
+        IR_dprintk(2, "RC6 decode started at state %i (%i units, %ius)\n",
+                   data->state, u, TO_US(duration));
+
+        if (DURATION(u) == 0 && data->state != STATE_FINISHED)
+                return 0;
+
+        switch (data->state) {
+
+        case STATE_INACTIVE:
+                if (u >= RC6_PREFIX_PULSE - 1 && u <= RC6_PREFIX_PULSE + 1) {
+                        data->state = STATE_PREFIX_SPACE;
+                        data->count = 0;
+                        return 0;
+                }
+                break;
+
+        case STATE_PREFIX_SPACE:
+                if (u == RC6_PREFIX_SPACE) {
+                        data->state = STATE_HEADER_BIT_START;
+                        return 0;
+                }
+                break;
+
+        case STATE_HEADER_BIT_START:
+                if (DURATION(u) == 1) {
+                        data->header <<= 1;
+                        if (IS_PULSE(u))
+                                data->header |= 1;
+                        data->count++;
+                        data->last_unit = u;
+                        data->state = STATE_HEADER_BIT_END;
+                        return 0;
+                }
+                break;
+
+        case STATE_HEADER_BIT_END:
+                if (IS_TRANSITION(u, data->last_unit)) {
+                        if (data->count == RC6_HEADER_NBITS)
+                                data->state = STATE_TOGGLE_START;
+                        else
+                                data->state = STATE_HEADER_BIT_START;
+
+                        DECREASE_DURATION(u, 1);
+                        goto again;
+                }
+                break;
+
+        case STATE_TOGGLE_START:
+                if (DURATION(u) == 2) {
+                        data->toggle = IS_PULSE(u);
+                        data->last_unit = u;
+                        data->state = STATE_TOGGLE_END;
+                        return 0;
+                }
+                break;
+
+        case STATE_TOGGLE_END:
+                if (IS_TRANSITION(u, data->last_unit) && DURATION(u) >= 2) {
+                        data->state = STATE_BODY_BIT_START;
+                        data->last_unit = u;
+                        DECREASE_DURATION(u, 2);
+                        data->count = 0;
+
+                        if (!(data->header & RC6_STARTBIT_MASK)) {
+                                IR_dprintk(1, "RC6 invalid start bit\n");
+                                break;
+                        }
+
+                        switch (rc6_mode(data)) {
+                        case RC6_MODE_0:
+                                data->wanted_bits = RC6_0_NBITS;
+                                break;
+                        case RC6_MODE_6A:
+                                /* This might look weird, but we basically
+                                   check the value of the first body bit to
+                                   determine the number of bits in mode 6A */
+                                if ((DURATION(u) == 0 && IS_SPACE(data->last_unit)) || DURATION(u) > 0)
+                                        data->wanted_bits = RC6_6A_LARGE_NBITS;
+                                else
+                                        data->wanted_bits = RC6_6A_SMALL_NBITS;
+                                break;
+                        default:
+                                IR_dprintk(1, "RC6 unknown mode\n");
+                                goto out;
+                        }
+                        goto again;
+                }
+                break;
+
+        case STATE_BODY_BIT_START:
+                if (DURATION(u) == 1) {
+                        data->body <<= 1;
+                        if (IS_PULSE(u))
+                                data->body |= 1;
+                        data->count++;
+                        data->last_unit = u;
+
+                        /*
+                         * If the last bit is one, a space will merge
+                         * with the silence after the command.
+                         */
+                        if (IS_PULSE(u) && data->count == data->wanted_bits) {
+                                data->state = STATE_FINISHED;
+                                goto again;
+                        }
+
+                        data->state = STATE_BODY_BIT_END;
+                        return 0;
+                }
+                break;
+
+        case STATE_BODY_BIT_END:
+                if (IS_TRANSITION(u, data->last_unit)) {
+                        if (data->count == data->wanted_bits)
+                                data->state = STATE_FINISHED;
+                        else
+                                data->state = STATE_BODY_BIT_START;
+
+                        DECREASE_DURATION(u, 1);
+                        goto again;
+                }
+                break;
+
+        case STATE_FINISHED:
+                switch (rc6_mode(data)) {
+                case RC6_MODE_0:
+                        scancode = data->body & 0xffff;
+                        toggle = data->toggle;
+                        IR_dprintk(1, "RC6(0) scancode 0x%04x (toggle: %u)\n",
+                                   scancode, toggle);
+                        break;
+                case RC6_MODE_6A:
+                        if (data->wanted_bits == RC6_6A_LARGE_NBITS) {
+                                toggle = data->body & RC6_6A_MCE_TOGGLE_MASK ? 1 : 0;
+                                scancode = data->body & ~RC6_6A_MCE_TOGGLE_MASK;
+                        } else {
+                                toggle = 0;
+                                scancode = data->body & 0xffffff;
+                        }
+
+                        IR_dprintk(1, "RC6(6A) scancode 0x%08x (toggle: %u)\n",
+                                   scancode, toggle);
+                        break;
+                default:
+                        IR_dprintk(1, "RC6 unknown mode\n");
+                        goto out;
+                }
+
+                ir_keydown(input_dev, scancode, toggle);
+                data->state = STATE_INACTIVE;
+                return 0;
+        }
+
+out:
+        IR_dprintk(1, "RC6 decode failed at state %i (%i units, %ius)\n",
+                   data->state, u, TO_US(duration));
+        data->state = STATE_INACTIVE;
+        return -EINVAL;
+}
+
+static int ir_rc6_register(struct input_dev *input_dev)
+{
+        struct ir_input_dev *ir_dev = input_get_drvdata(input_dev);
+        struct decoder_data *data;
+        int rc;
+
+        rc = sysfs_create_group(&ir_dev->dev.kobj, &decoder_attribute_group);
+        if (rc < 0)
+                return rc;
+
+        data = kzalloc(sizeof(*data), GFP_KERNEL);
+        if (!data) {
+                sysfs_remove_group(&ir_dev->dev.kobj, &decoder_attribute_group);
+                return -ENOMEM;
+        }
+
+        data->ir_dev = ir_dev;
+        data->enabled = 1;
+
+        spin_lock(&decoder_lock);
+        list_add_tail(&data->list, &decoder_list);
+        spin_unlock(&decoder_lock);
+
+        return 0;
+}
+
+static int ir_rc6_unregister(struct input_dev *input_dev)
+{
+        struct ir_input_dev *ir_dev = input_get_drvdata(input_dev);
+        static struct decoder_data *data;
+
+        data = get_decoder_data(ir_dev);
+        if (!data)
+                return 0;
+
+        sysfs_remove_group(&ir_dev->dev.kobj, &decoder_attribute_group);
+
+        spin_lock(&decoder_lock);
+        list_del(&data->list);
+        spin_unlock(&decoder_lock);
+
+        return 0;
+}
+
+static struct ir_raw_handler rc6_handler = {
+        .decode         = ir_rc6_decode,
+        .raw_register   = ir_rc6_register,
+        .raw_unregister = ir_rc6_unregister,
+};
+
+static int __init ir_rc6_decode_init(void)
+{
+        ir_raw_handler_register(&rc6_handler);
+
+        printk(KERN_INFO "IR RC6 protocol handler initialized\n");
+        return 0;
+}
+
+static void __exit ir_rc6_decode_exit(void)
+{
+        ir_raw_handler_unregister(&rc6_handler);
+}
+
+module_init(ir_rc6_decode_init);
+module_exit(ir_rc6_decode_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("David Härdeman <david@hardeman.nu>");
+MODULE_DESCRIPTION("RC6 IR protocol decoder");
diff --git a/drivers/media/IR/ir-sysfs.c b/drivers/media/IR/ir-sysfs.c
index 57f09c4ca9fb..073b5c0dc654 100644
--- a/drivers/media/IR/ir-sysfs.c
+++ b/drivers/media/IR/ir-sysfs.c
@@ -61,6 +61,8 @@ static ssize_t show_protocol(struct device *d,
                 s = "pulse-distance";
         else if (ir_type == IR_TYPE_NEC)
                 s = "nec";
+        else if (ir_type == IR_TYPE_RC6)
+                s = "rc6";
         else
                 s = "other";