[ALSA] Add pcm_class attribute to PCM sysfs entry

This patch adds a new attribute, pcm_class, to each PCM sysfs entry.
It's useful to detect what kind of PCM stream is, for example, HAL
can check whether it's a modem or not.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>

diff --git a/include/sound/core.h b/include/sound/core.h
index 1359c532b68e39b1fd48c541c8690fd9fb866010..b056ea925ecf33c7e06bf6e3d7c4d27d8f66a9b1 100644 (file)
--- a/include/sound/core.h
+++ b/include/sound/core.h
@@ -26,6 +26,7 @@
 #include <linux/mutex.h>               /* struct mutex */
 #include <linux/rwsem.h>               /* struct rw_semaphore */
 #include <linux/pm.h>                  /* pm_message_t */
+#include <linux/device.h>
 
 /* forward declarations */
 #ifdef CONFIG_PCI
@@ -186,6 +187,7 @@ struct snd_minor {
        int device;                     /* device number */
        const struct file_operations *f_ops;    /* file operations */
        void *private_data;             /* private data for f_ops->open */
+       struct class_device *class_dev; /* class device for sysfs */
 };
 
 /* sound.c */
@@ -200,6 +202,8 @@ int snd_register_device(int type, struct snd_card *card, int dev,
                        const char *name);
 int snd_unregister_device(int type, struct snd_card *card, int dev);
 void *snd_lookup_minor_data(unsigned int minor, int type);
+int snd_add_device_sysfs_file(int type, struct snd_card *card, int dev,
+                             const struct class_device_attribute *attr);
 
 #ifdef CONFIG_SND_OSSEMUL
 int snd_register_oss_device(int type, struct snd_card *card, int dev,

diff --git a/sound/core/pcm.c b/sound/core/pcm.c
index ed3b09469560be86a7ddaa10183b845dfbf8bd3e..bf8f412988b8ead58fe147d102c006fda12b78fb 100644 (file)
--- a/sound/core/pcm.c
+++ b/sound/core/pcm.c
@@ -907,6 +907,28 @@ void snd_pcm_detach_substream(struct snd_pcm_substream *substream)
        substream->pstr->substream_opened--;
 }
 
+static ssize_t show_pcm_class(struct class_device *class_device, char *buf)
+{
+       struct snd_pcm *pcm;
+       const char *str;
+       static const char *strs[SNDRV_PCM_CLASS_LAST + 1] = {
+               [SNDRV_PCM_CLASS_GENERIC] = "generic",
+               [SNDRV_PCM_CLASS_MULTI] = "multi",
+               [SNDRV_PCM_CLASS_MODEM] = "modem",
+               [SNDRV_PCM_CLASS_DIGITIZER] = "digitizer",
+       };
+
+       if (! (pcm = class_get_devdata(class_device)) ||
+           pcm->dev_class > SNDRV_PCM_CLASS_LAST)
+               str = "none";
+       else
+               str = strs[pcm->dev_class];
+        return snprintf(buf, PAGE_SIZE, "%s\n", str);
+}
+
+static struct class_device_attribute pcm_attrs =
+       __ATTR(pcm_class, S_IRUGO, show_pcm_class, NULL);
+
 static int snd_pcm_dev_register(struct snd_device *device)
 {
        int cidx, err;
@@ -945,6 +967,8 @@ static int snd_pcm_dev_register(struct snd_device *device)
                        mutex_unlock(&register_mutex);
                        return err;
                }
+               snd_add_device_sysfs_file(devtype, pcm->card, pcm->device,
+                                         &pcm_attrs);
                for (substream = pcm->streams[cidx].substream; substream; substream = substream->next)
                        snd_pcm_timer_init(substream);
        }

diff --git a/sound/core/sound.c b/sound/core/sound.c
index b4430db3fa4c69b0581dfcee3cedb5a75e31cc36..efa476c5210ac52832d8e7154984d42717d8588b 100644 (file)
--- a/sound/core/sound.c
+++ b/sound/core/sound.c
@@ -268,7 +268,11 @@ int snd_register_device(int type, struct snd_card *card, int dev,
        snd_minors[minor] = preg;
        if (card)
                device = card->dev;
-       class_device_create(sound_class, NULL, MKDEV(major, minor), device, "%s", name);
+       preg->class_dev = class_device_create(sound_class, NULL,
+                                             MKDEV(major, minor),
+                                             device, "%s", name);
+       if (preg->class_dev)
+               class_set_devdata(preg->class_dev, private_data);
 
        mutex_unlock(&sound_mutex);
        return 0;
@@ -276,6 +280,24 @@ int snd_register_device(int type, struct snd_card *card, int dev,
 
 EXPORT_SYMBOL(snd_register_device);
 
+/* find the matching minor record
+ * return the index of snd_minor, or -1 if not found
+ */
+static int find_snd_minor(int type, struct snd_card *card, int dev)
+{
+       int cardnum, minor;
+       struct snd_minor *mptr;
+
+       cardnum = card ? card->number : -1;
+       for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor)
+               if ((mptr = snd_minors[minor]) != NULL &&
+                   mptr->type == type &&
+                   mptr->card == cardnum &&
+                   mptr->device == dev)
+                       return minor;
+       return -1;
+}
+
 /**
  * snd_unregister_device - unregister the device on the given card
  * @type: the device type, SNDRV_DEVICE_TYPE_XXX
@@ -289,32 +311,42 @@ EXPORT_SYMBOL(snd_register_device);
  */
 int snd_unregister_device(int type, struct snd_card *card, int dev)
 {
-       int cardnum, minor;
-       struct snd_minor *mptr;
+       int minor;
 
-       cardnum = card ? card->number : -1;
        mutex_lock(&sound_mutex);
-       for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor)
-               if ((mptr = snd_minors[minor]) != NULL &&
-                   mptr->type == type &&
-                   mptr->card == cardnum &&
-                   mptr->device == dev)
-                       break;
-       if (minor == ARRAY_SIZE(snd_minors)) {
+       minor = find_snd_minor(type, card, dev);
+       if (minor < 0) {
                mutex_unlock(&sound_mutex);
                return -EINVAL;
        }
 
        class_device_destroy(sound_class, MKDEV(major, minor));
 
+       kfree(snd_minors[minor]);
        snd_minors[minor] = NULL;
        mutex_unlock(&sound_mutex);
-       kfree(mptr);
        return 0;
 }
 
 EXPORT_SYMBOL(snd_unregister_device);
 
+int snd_add_device_sysfs_file(int type, struct snd_card *card, int dev,
+                             const struct class_device_attribute *attr)
+{
+       int minor, ret = -EINVAL;
+       struct class_device *cdev;
+
+       mutex_lock(&sound_mutex);
+       minor = find_snd_minor(type, card, dev);
+       if (minor >= 0 && (cdev = snd_minors[minor]->class_dev) != NULL)
+               ret = class_device_create_file(cdev, attr);
+       mutex_unlock(&sound_mutex);
+       return ret;
+
+}
+
+EXPORT_SYMBOL(snd_add_device_sysfs_file);
+
 #ifdef CONFIG_PROC_FS
 /*
  *  INFO PART