[ALSA] usb-audio - add Extigy/Audigy 2 NX remote control support

ALSA Core,USB generic driver
Add an hwdep interface that supports reading remote control data from
Sound Blaster Extigy and Audigy 2 NX devices.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>

2 files changed, 161 insertions, 1 deletions

diff --git a/include/sound/asound.h b/include/sound/asound.h
index 26db585a1819..4321e92a7f8b 100644
--- a/include/sound/asound.h
+++ b/include/sound/asound.h
@@ -113,9 +113,10 @@ enum sndrv_hwdep_iface {
         SNDRV_HWDEP_IFACE_BLUETOOTH,    /* Bluetooth audio */
         SNDRV_HWDEP_IFACE_USX2Y_PCM,    /* Tascam US122, US224 & US428 rawusb pcm */
         SNDRV_HWDEP_IFACE_PCXHR,        /* Digigram PCXHR */
+        SNDRV_HWDEP_IFACE_SB_RC,        /* SB Extigy/Audigy2NX remote control */
 
         /* Don't forget to change the following: */
-        SNDRV_HWDEP_IFACE_LAST = SNDRV_HWDEP_IFACE_PCXHR
+        SNDRV_HWDEP_IFACE_LAST = SNDRV_HWDEP_IFACE_SB_RC
 };
 
 struct sndrv_hwdep_info {
diff --git a/sound/usb/usbmixer.c b/sound/usb/usbmixer.c
index dd045ea6fb01..7ea42d43d7ff 100644
--- a/sound/usb/usbmixer.c
+++ b/sound/usb/usbmixer.c
@@ -35,6 +35,7 @@
 #include <linux/usb.h>
 #include <sound/core.h>
 #include <sound/control.h>
+#include <sound/hwdep.h>
 
 #include "usbaudio.h"
 
@@ -57,6 +58,19 @@ struct usb_mixer_interface {
         unsigned int ignore_ctl_error;
         struct urb *urb;
         usb_mixer_elem_info_t **id_elems; /* array[256], indexed by unit id */
+
+        /* Sound Blaster remote control stuff */
+        enum {
+                RC_NONE,
+                RC_EXTIGY,
+                RC_AUDIGY2NX,
+        } rc_type;
+        unsigned long rc_hwdep_open;
+        u32 rc_code;
+        wait_queue_head_t rc_waitq;
+        struct urb *rc_urb;
+        struct usb_ctrlrequest *rc_setup_packet;
+        u8 rc_buffer[6];
 };
 
 
@@ -1536,6 +1550,9 @@ static void snd_usb_mixer_free(struct usb_mixer_interface *mixer)
                 kfree(mixer->urb->transfer_buffer);
                 usb_free_urb(mixer->urb);
         }
+        if (mixer->rc_urb)
+                usb_free_urb(mixer->rc_urb);
+        kfree(mixer->rc_setup_packet);
         kfree(mixer);
 }
 
@@ -1604,6 +1621,17 @@ static void snd_usb_mixer_notify_id(struct usb_mixer_interface *mixer,
                                info->elem_id);
 }
 
+static void snd_usb_mixer_memory_change(struct usb_mixer_interface *mixer,
+                                        int unitid)
+{
+        /* SB remote control */
+        if (mixer->rc_type != RC_NONE && unitid == 0) {
+                /* read control code from device memory */
+                mixer->rc_urb->dev = mixer->chip->dev;
+                usb_submit_urb(mixer->rc_urb, GFP_ATOMIC);
+        }
+}
+
 static void snd_usb_mixer_status_complete(struct urb *urb, struct pt_regs *regs)
 {
         struct usb_mixer_interface *mixer = urb->context;
@@ -1620,6 +1648,8 @@ static void snd_usb_mixer_status_complete(struct urb *urb, struct pt_regs *regs)
                                 continue;
                         if (!(buf[0] & 0x40))
                                 snd_usb_mixer_notify_id(mixer, buf[1]);
+                        else
+                                snd_usb_mixer_memory_change(mixer, buf[1]);
                 }
         }
         if (urb->status != -ENOENT && urb->status != -ECONNRESET) {
@@ -1664,6 +1694,126 @@ static int snd_usb_mixer_status_create(struct usb_mixer_interface *mixer)
         return 0;
 }
 
+static void snd_usb_soundblaster_remote_complete(struct urb *urb,
+                                                 struct pt_regs *regs)
+{
+        struct usb_mixer_interface *mixer = urb->context;
+        /*
+         * format of remote control data:
+         * Extigy:      xx 00
+         * Audigy 2 NX: 06 80 xx 00 00 00
+         */
+        int offset = mixer->rc_type == RC_EXTIGY ? 0 : 2;
+        u32 code;
+
+        if (urb->status < 0 || urb->actual_length <= offset)
+                return;
+        code = mixer->rc_buffer[offset];
+        /* the Mute button actually changes the mixer control */
+        if (code == 13)
+                snd_usb_mixer_notify_id(mixer, 18);
+        mixer->rc_code = code;
+        wmb();
+        wake_up(&mixer->rc_waitq);
+}
+
+static int snd_usb_sbrc_hwdep_open(snd_hwdep_t *hw, struct file *file)
+{
+        struct usb_mixer_interface *mixer = hw->private_data;
+
+        if (test_and_set_bit(0, &mixer->rc_hwdep_open))
+                return -EBUSY;
+        return 0;
+}
+
+static int snd_usb_sbrc_hwdep_release(snd_hwdep_t *hw, struct file *file)
+{
+        struct usb_mixer_interface *mixer = hw->private_data;
+
+        clear_bit(0, &mixer->rc_hwdep_open);
+        smp_mb__after_clear_bit();
+        return 0;
+}
+
+static long snd_usb_sbrc_hwdep_read(snd_hwdep_t *hw, char __user *buf,
+                                     long count, loff_t *offset)
+{
+        struct usb_mixer_interface *mixer = hw->private_data;
+        int err;
+        u32 rc_code;
+
+        if (count != 1)
+                return -EINVAL;
+        err = wait_event_interruptible(mixer->rc_waitq,
+                                       (rc_code = xchg(&mixer->rc_code, 0)) != 0);
+        if (err == 0) {
+                err = put_user(rc_code, buf);
+        }
+        return err < 0 ? err : count;
+}
+
+static unsigned int snd_usb_sbrc_hwdep_poll(snd_hwdep_t *hw, struct file *file,
+                                            poll_table *wait)
+{
+        struct usb_mixer_interface *mixer = hw->private_data;
+
+        poll_wait(file, &mixer->rc_waitq, wait);
+        return mixer->rc_code ? POLLIN | POLLRDNORM : 0;
+}
+
+static int snd_usb_soundblaster_remote_init(struct usb_mixer_interface *mixer)
+{
+        snd_hwdep_t *hwdep;
+        int err, len;
+
+        switch (le16_to_cpu(mixer->chip->dev->descriptor.idProduct)) {
+        case 0x3000:
+                mixer->rc_type = RC_EXTIGY;
+                len = 2;
+                break;
+        case 0x3020:
+                mixer->rc_type = RC_AUDIGY2NX;
+                len = 6;
+                break;
+        default:
+                return 0;
+        }
+
+        init_waitqueue_head(&mixer->rc_waitq);
+        err = snd_hwdep_new(mixer->chip->card, "SB remote control", 0, &hwdep);
+        if (err < 0)
+                return err;
+        snprintf(hwdep->name, sizeof(hwdep->name),
+                 "%s remote control", mixer->chip->card->shortname);
+        hwdep->iface = SNDRV_HWDEP_IFACE_SB_RC;
+        hwdep->private_data = mixer;
+        hwdep->ops.read = snd_usb_sbrc_hwdep_read;
+        hwdep->ops.open = snd_usb_sbrc_hwdep_open;
+        hwdep->ops.release = snd_usb_sbrc_hwdep_release;
+        hwdep->ops.poll = snd_usb_sbrc_hwdep_poll;
+
+        mixer->rc_urb = usb_alloc_urb(0, GFP_KERNEL);
+        if (!mixer->rc_urb)
+                return -ENOMEM;
+        mixer->rc_setup_packet = kmalloc(sizeof(*mixer->rc_setup_packet), GFP_KERNEL);
+        if (!mixer->rc_setup_packet) {
+                usb_free_urb(mixer->rc_urb);
+                mixer->rc_urb = NULL;
+                return -ENOMEM;
+        }
+        mixer->rc_setup_packet->bRequestType =
+                USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE;
+        mixer->rc_setup_packet->bRequest = GET_MEM;
+        mixer->rc_setup_packet->wValue = cpu_to_le16(0);
+        mixer->rc_setup_packet->wIndex = cpu_to_le16(0);
+        mixer->rc_setup_packet->wLength = cpu_to_le16(len);
+        usb_fill_control_urb(mixer->rc_urb, mixer->chip->dev,
+                             usb_rcvctrlpipe(mixer->chip->dev, 0),
+                             (u8*)mixer->rc_setup_packet, mixer->rc_buffer, len,
+                             snd_usb_soundblaster_remote_complete, mixer);
+        return 0;
+}
+
 int snd_usb_create_mixer(snd_usb_audio_t *chip, int ctrlif)
 {
         static snd_device_ops_t dev_ops = {
@@ -1694,6 +1844,13 @@ int snd_usb_create_mixer(snd_usb_audio_t *chip, int ctrlif)
                 return err;
         }
 
+        if (le16_to_cpu(chip->dev->descriptor.idVendor) == 0x041e) {
+                if ((err = snd_usb_soundblaster_remote_init(mixer)) < 0) {
+                        snd_usb_mixer_free(mixer);
+                        return err;
+                }
+        }
+
         err = snd_device_new(chip->card, SNDRV_DEV_LOWLEVEL, mixer, &dev_ops);
         if (err < 0) {
                 snd_usb_mixer_free(mixer);
@@ -1710,4 +1867,6 @@ void snd_usb_mixer_disconnect(struct list_head *p)
         mixer = list_entry(p, struct usb_mixer_interface, list);
         if (mixer->urb)
                 usb_kill_urb(mixer->urb);
+        if (mixer->rc_urb)
+                usb_kill_urb(mixer->rc_urb);
 }