[media] rc-core: add loopback driver

This patch adds a loopback driver to rc-core which I've found useful for
running scripted tests of different parts of rc-core without having to
fiddle with real hardware.

Basically it emulates hardware with a learning and a non-learning
receiver and two transmitters (which correspond to the two
receivers). TX data that is sent is fed back as input on the
corresponding receiver, which allows for debugging of IR decoders,
keymaps, etc.

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

3 files changed, 274 insertions, 0 deletions

diff --git a/drivers/media/rc/Kconfig b/drivers/media/rc/Kconfig
index 42b4feb0e7f9..3785162f928e 100644
--- a/drivers/media/rc/Kconfig
+++ b/drivers/media/rc/Kconfig
@@ -177,4 +177,17 @@ config IR_WINBOND_CIR
            To compile this driver as a module, choose M here: the module will
            be called winbond_cir.
 
+config RC_LOOPBACK
+        tristate "Remote Control Loopback Driver"
+        depends on RC_CORE
+        ---help---
+           Say Y here if you want support for the remote control loopback
+           driver which allows TX data to be sent back as RX data.
+           This is mostly useful for debugging purposes.
+
+           If you're not sure, select N here.
+
+           To compile this driver as a module, choose M here: the module will
+           be called rc_loopback.
+
 endif #RC_CORE
diff --git a/drivers/media/rc/Makefile b/drivers/media/rc/Makefile
index 78ac8c5c8adc..67b4f7fe2577 100644
--- a/drivers/media/rc/Makefile
+++ b/drivers/media/rc/Makefile
@@ -19,3 +19,4 @@ obj-$(CONFIG_IR_NUVOTON) += nuvoton-cir.o
 obj-$(CONFIG_IR_ENE) += ene_ir.o
 obj-$(CONFIG_IR_STREAMZAP) += streamzap.o
 obj-$(CONFIG_IR_WINBOND_CIR) += winbond-cir.o
+obj-$(CONFIG_RC_LOOPBACK) += rc-loopback.o
diff --git a/drivers/media/rc/rc-loopback.c b/drivers/media/rc/rc-loopback.c
new file mode 100644
index 000000000000..49cee61d79c6
--- /dev/null
+++ b/drivers/media/rc/rc-loopback.c
@@ -0,0 +1,260 @@
+/*
+ * Loopback driver for rc-core,
+ *
+ * Copyright (c) 2010 David Härdeman <david@hardeman.nu>
+ *
+ * This driver receives TX data and passes it back as RX data,
+ * which is useful for (scripted) debugging of rc-core without
+ * having to use actual hardware.
+ *
+ * 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; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ */
+
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <media/rc-core.h>
+
+#define DRIVER_NAME     "rc-loopback"
+#define dprintk(x...)   if (debug) printk(KERN_INFO DRIVER_NAME ": " x)
+#define RXMASK_REGULAR  0x1
+#define RXMASK_LEARNING 0x2
+
+static bool debug;
+
+struct loopback_dev {
+        struct rc_dev *dev;
+        u32 txmask;
+        u32 txcarrier;
+        u32 txduty;
+        bool idle;
+        bool learning;
+        bool carrierreport;
+        u32 rxcarriermin;
+        u32 rxcarriermax;
+};
+
+static struct loopback_dev loopdev;
+
+static int loop_set_tx_mask(struct rc_dev *dev, u32 mask)
+{
+        struct loopback_dev *lodev = dev->priv;
+
+        if ((mask & (RXMASK_REGULAR | RXMASK_LEARNING)) != mask) {
+                dprintk("invalid tx mask: %u\n", mask);
+                return -EINVAL;
+        }
+
+        dprintk("setting tx mask: %u\n", mask);
+        lodev->txmask = mask;
+        return 0;
+}
+
+static int loop_set_tx_carrier(struct rc_dev *dev, u32 carrier)
+{
+        struct loopback_dev *lodev = dev->priv;
+
+        dprintk("setting tx carrier: %u\n", carrier);
+        lodev->txcarrier = carrier;
+        return 0;
+}
+
+static int loop_set_tx_duty_cycle(struct rc_dev *dev, u32 duty_cycle)
+{
+        struct loopback_dev *lodev = dev->priv;
+
+        if (duty_cycle < 1 || duty_cycle > 99) {
+                dprintk("invalid duty cycle: %u\n", duty_cycle);
+                return -EINVAL;
+        }
+
+        dprintk("setting duty cycle: %u\n", duty_cycle);
+        lodev->txduty = duty_cycle;
+        return 0;
+}
+
+static int loop_set_rx_carrier_range(struct rc_dev *dev, u32 min, u32 max)
+{
+        struct loopback_dev *lodev = dev->priv;
+
+        if (min < 1 || min > max) {
+                dprintk("invalid rx carrier range %u to %u\n", min, max);
+                return -EINVAL;
+        }
+
+        dprintk("setting rx carrier range %u to %u\n", min, max);
+        lodev->rxcarriermin = min;
+        lodev->rxcarriermax = max;
+        return 0;
+}
+
+static int loop_tx_ir(struct rc_dev *dev, int *txbuf, u32 n)
+{
+        struct loopback_dev *lodev = dev->priv;
+        u32 rxmask;
+        unsigned count;
+        unsigned total_duration = 0;
+        unsigned i;
+        DEFINE_IR_RAW_EVENT(rawir);
+
+        if (n == 0 || n % sizeof(int)) {
+                dprintk("invalid tx buffer size\n");
+                return -EINVAL;
+        }
+
+        count = n / sizeof(int);
+        for (i = 0; i < count; i++)
+                total_duration += abs(txbuf[i]);
+
+        if (total_duration == 0) {
+                dprintk("invalid tx data, total duration zero\n");
+                return -EINVAL;
+        }
+
+        if (lodev->txcarrier < lodev->rxcarriermin ||
+            lodev->txcarrier > lodev->rxcarriermax) {
+                dprintk("ignoring tx, carrier out of range\n");
+                goto out;
+        }
+
+        if (lodev->learning)
+                rxmask = RXMASK_LEARNING;
+        else
+                rxmask = RXMASK_REGULAR;
+
+        if (!(rxmask & lodev->txmask)) {
+                dprintk("ignoring tx, rx mask mismatch\n");
+                goto out;
+        }
+
+        for (i = 0; i < count; i++) {
+                rawir.pulse = i % 2 ? false : true;
+                rawir.duration = abs(txbuf[i]) * 1000;
+                if (rawir.duration)
+                        ir_raw_event_store_with_filter(dev, &rawir);
+        }
+        ir_raw_event_handle(dev);
+
+out:
+        /* Lirc expects this function to take as long as the total duration */
+        set_current_state(TASK_INTERRUPTIBLE);
+        schedule_timeout(usecs_to_jiffies(total_duration));
+        return n;
+}
+
+static void loop_set_idle(struct rc_dev *dev, bool enable)
+{
+        struct loopback_dev *lodev = dev->priv;
+
+        if (lodev->idle != enable) {
+                dprintk("%sing idle mode\n", enable ? "enter" : "exit");
+                lodev->idle = enable;
+        }
+}
+
+static int loop_set_learning_mode(struct rc_dev *dev, int enable)
+{
+        struct loopback_dev *lodev = dev->priv;
+
+        if (lodev->learning != enable) {
+                dprintk("%sing learning mode\n", enable ? "enter" : "exit");
+                lodev->learning = !!enable;
+        }
+
+        return 0;
+}
+
+static int loop_set_carrier_report(struct rc_dev *dev, int enable)
+{
+        struct loopback_dev *lodev = dev->priv;
+
+        if (lodev->carrierreport != enable) {
+                dprintk("%sabling carrier reports\n", enable ? "en" : "dis");
+                lodev->carrierreport = !!enable;
+        }
+
+        return 0;
+}
+
+static int __init loop_init(void)
+{
+        struct rc_dev *rc;
+        int ret;
+
+        rc = rc_allocate_device();
+        if (!rc) {
+                printk(KERN_ERR DRIVER_NAME ": rc_dev allocation failed\n");
+                return -ENOMEM;
+        }
+
+        rc->input_name          = "rc-core loopback device";
+        rc->input_phys          = "rc-core/virtual";
+        rc->input_id.bustype    = BUS_VIRTUAL;
+        rc->input_id.version    = 1;
+        rc->driver_name         = DRIVER_NAME;
+        rc->map_name            = RC_MAP_EMPTY;
+        rc->priv                = &loopdev;
+        rc->driver_type         = RC_DRIVER_IR_RAW;
+        rc->allowed_protos      = RC_TYPE_ALL;
+        rc->timeout             = 100 * 1000 * 1000; /* 100 ms */
+        rc->min_timeout         = 1;
+        rc->max_timeout         = UINT_MAX;
+        rc->rx_resolution       = 1000;
+        rc->tx_resolution       = 1000;
+        rc->s_tx_mask           = loop_set_tx_mask;
+        rc->s_tx_carrier        = loop_set_tx_carrier;
+        rc->s_tx_duty_cycle     = loop_set_tx_duty_cycle;
+        rc->s_rx_carrier_range  = loop_set_rx_carrier_range;
+        rc->tx_ir               = loop_tx_ir;
+        rc->s_idle              = loop_set_idle;
+        rc->s_learning_mode     = loop_set_learning_mode;
+        rc->s_carrier_report    = loop_set_carrier_report;
+        rc->priv                = &loopdev;
+
+        loopdev.txmask          = RXMASK_REGULAR;
+        loopdev.txcarrier       = 36000;
+        loopdev.txduty          = 50;
+        loopdev.rxcarriermin    = 1;
+        loopdev.rxcarriermax    = ~0;
+        loopdev.idle            = true;
+        loopdev.learning        = false;
+        loopdev.carrierreport   = false;
+
+        ret = rc_register_device(rc);
+        if (ret < 0) {
+                printk(KERN_ERR DRIVER_NAME ": rc_dev registration failed\n");
+                rc_free_device(rc);
+                return ret;
+        }
+
+        loopdev.dev = rc;
+        return 0;
+}
+
+static void __exit loop_exit(void)
+{
+        rc_unregister_device(loopdev.dev);
+}
+
+module_init(loop_init);
+module_exit(loop_exit);
+
+module_param(debug, bool, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(debug, "Enable debug messages");
+
+MODULE_DESCRIPTION("Loopback device for rc-core debugging");
+MODULE_AUTHOR("David Härdeman <david@hardeman.nu>");
+MODULE_LICENSE("GPL");