1 files changed, 324 insertions, 0 deletions

diff --git a/drivers/media/IR/ir-rc5-decoder.c b/drivers/media/IR/ir-rc5-decoder.c
new file mode 100644
index 000000000000..23cdb1b1a3bc
--- /dev/null
+++ b/drivers/media/IR/ir-rc5-decoder.c
@@ -0,0 +1,324 @@
+/* ir-rc5-decoder.c - handle RC5(x) IR Pulse/Space protocol
+ *
+ * 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.
+ */
+
+/*
+ * This code handles 14 bits RC5 protocols and 20 bits RC5x protocols.
+ * There are other variants that use a different number of bits.
+ * This is currently unsupported.
+ * It considers a carrier of 36 kHz, with a total of 14/20 bits, where
+ * the first two bits are start bits, and a third one is a filing bit
+ */
+
+#include "ir-core-priv.h"
+
+#define RC5_NBITS               14
+#define RC5X_NBITS              20
+#define CHECK_RC5X_NBITS        8
+#define RC5_UNIT                888888 /* ns */
+#define RC5_BIT_START           (1 * RC5_UNIT)
+#define RC5_BIT_END             (1 * RC5_UNIT)
+#define RC5X_SPACE              (4 * RC5_UNIT)
+
+/* Used to register rc5_decoder clients */
+static LIST_HEAD(decoder_list);
+static DEFINE_SPINLOCK(decoder_lock);
+
+enum rc5_state {
+        STATE_INACTIVE,
+        STATE_BIT_START,
+        STATE_BIT_END,
+        STATE_CHECK_RC5X,
+        STATE_FINISHED,
+};
+
+struct decoder_data {
+        struct list_head        list;
+        struct ir_input_dev     *ir_dev;
+        int                     enabled:1;
+
+        /* State machine control */
+        enum rc5_state          state;
+        u32                     rc5_bits;
+        struct ir_raw_event     prev_ev;
+        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   = "rc5_decoder",
+        .attrs  = decoder_attributes,
+};
+
+/**
+ * ir_rc5_decode() - Decode one RC-5 pulse or space
+ * @input_dev:  the struct input_dev descriptor of the device
+ * @ev:         the struct ir_raw_event descriptor of the pulse/space
+ *
+ * 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)
+{
+        struct decoder_data *data;
+        struct ir_input_dev *ir_dev = input_get_drvdata(input_dev);
+        u8 toggle;
+        u32 scancode;
+
+        data = get_decoder_data(ir_dev);
+        if (!data)
+                return -EINVAL;
+
+        if (!data->enabled)
+                return 0;
+
+        if (IS_RESET(ev)) {
+                data->state = STATE_INACTIVE;
+                return 0;
+        }
+
+        if (!geq_margin(ev.duration, RC5_UNIT, RC5_UNIT / 2))
+                goto out;
+
+again:
+        IR_dprintk(2, "RC5(x) decode started at state %i (%uus %s)\n",
+                   data->state, TO_US(ev.duration), TO_STR(ev.pulse));
+
+        if (!geq_margin(ev.duration, RC5_UNIT, RC5_UNIT / 2))
+                return 0;
+
+        switch (data->state) {
+
+        case STATE_INACTIVE:
+                if (!ev.pulse)
+                        break;
+
+                data->state = STATE_BIT_START;
+                data->count = 1;
+                /* We just need enough bits to get to STATE_CHECK_RC5X */
+                data->wanted_bits = RC5X_NBITS;
+                decrease_duration(&ev, RC5_BIT_START);
+                goto again;
+
+        case STATE_BIT_START:
+                if (!eq_margin(ev.duration, RC5_BIT_START, RC5_UNIT / 2))
+                        break;
+
+                data->rc5_bits <<= 1;
+                if (!ev.pulse)
+                        data->rc5_bits |= 1;
+                data->count++;
+                data->prev_ev = ev;
+                data->state = STATE_BIT_END;
+                return 0;
+
+        case STATE_BIT_END:
+                if (!is_transition(&ev, &data->prev_ev))
+                        break;
+
+                if (data->count == data->wanted_bits)
+                        data->state = STATE_FINISHED;
+                else if (data->count == CHECK_RC5X_NBITS)
+                        data->state = STATE_CHECK_RC5X;
+                else
+                        data->state = STATE_BIT_START;
+
+                decrease_duration(&ev, RC5_BIT_END);
+                goto again;
+
+        case STATE_CHECK_RC5X:
+                if (!ev.pulse && geq_margin(ev.duration, RC5X_SPACE, RC5_UNIT / 2)) {
+                        /* RC5X */
+                        data->wanted_bits = RC5X_NBITS;
+                        decrease_duration(&ev, RC5X_SPACE);
+                } else {
+                        /* RC5 */
+                        data->wanted_bits = RC5_NBITS;
+                }
+                data->state = STATE_BIT_START;
+                goto again;
+
+        case STATE_FINISHED:
+                if (ev.pulse)
+                        break;
+
+                if (data->wanted_bits == RC5X_NBITS) {
+                        /* RC5X */
+                        u8 xdata, command, system;
+                        xdata    = (data->rc5_bits & 0x0003F) >> 0;
+                        command  = (data->rc5_bits & 0x00FC0) >> 6;
+                        system   = (data->rc5_bits & 0x1F000) >> 12;
+                        toggle   = (data->rc5_bits & 0x20000) ? 1 : 0;
+                        command += (data->rc5_bits & 0x01000) ? 0 : 0x40;
+                        scancode = system << 16 | command << 8 | xdata;
+
+                        IR_dprintk(1, "RC5X scancode 0x%06x (toggle: %u)\n",
+                                   scancode, toggle);
+
+                } else {
+                        /* RC5 */
+                        u8 command, system;
+                        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;
+        }
+
+out:
+        IR_dprintk(1, "RC5(x) decode failed at state %i (%uus %s)\n",
+                   data->state, TO_US(ev.duration), TO_STR(ev.pulse));
+        data->state = STATE_INACTIVE;
+        return -EINVAL;
+}
+
+static int ir_rc5_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_rc5_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 rc5_handler = {
+        .decode         = ir_rc5_decode,
+        .raw_register   = ir_rc5_register,
+        .raw_unregister = ir_rc5_unregister,
+};
+
+static int __init ir_rc5_decode_init(void)
+{
+        ir_raw_handler_register(&rc5_handler);
+
+        printk(KERN_INFO "IR RC5(x) protocol handler initialized\n");
+        return 0;
+}
+
+static void __exit ir_rc5_decode_exit(void)
+{
+        ir_raw_handler_unregister(&rc5_handler);
+}
+
+module_init(ir_rc5_decode_init);
+module_exit(ir_rc5_decode_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Mauro Carvalho Chehab <mchehab@redhat.com>");
+MODULE_AUTHOR("Red Hat Inc. (http://www.redhat.com)");
+MODULE_DESCRIPTION("RC5(x) IR protocol decoder");