ALSA: hda - Add hint string helper functions

Added snd_hda_get_hint() and snd_hda_get_bool_hint() helper functions
to retrieve a hint value.

Internally, the hint is stored in a pair of two strings, key and val.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 99 insertions, 13 deletions

diff --git a/sound/pci/hda/hda_hwdep.c b/sound/pci/hda/hda_hwdep.c
index 4af484b8240c..5e554de9cd9b 100644
--- a/sound/pci/hda/hda_hwdep.c
+++ b/sound/pci/hda/hda_hwdep.c
@@ -30,6 +30,12 @@
 #include <sound/hda_hwdep.h>
 #include <sound/minors.h>
 
+/* hint string pair */
+struct hda_hint {
+        const char *key;
+        const char *val;        /* contained in the same alloc as key */
+};
+
 /*
  * write/read an out-of-bound verb
  */
@@ -99,15 +105,15 @@ static int hda_hwdep_open(struct snd_hwdep *hw, struct file *file)
 
 static void clear_hwdep_elements(struct hda_codec *codec)
 {
-        char **head;
         int i;
 
         /* clear init verbs */
         snd_array_free(&codec->init_verbs);
         /* clear hints */
-        head = codec->hints.list;
-        for (i = 0; i < codec->hints.used; i++, head++)
-                kfree(*head);
+        for (i = 0; i < codec->hints.used; i++) {
+                struct hda_hint *hint = snd_array_elem(&codec->hints, i);
+                kfree(hint->key); /* we don't need to free hint->val */
+        }
         snd_array_free(&codec->hints);
         snd_array_free(&codec->user_pins);
 }
@@ -141,7 +147,7 @@ int /*__devinit*/ snd_hda_create_hwdep(struct hda_codec *codec)
 #endif
 
         snd_array_init(&codec->init_verbs, sizeof(struct hda_verb), 32);
-        snd_array_init(&codec->hints, sizeof(char *), 32);
+        snd_array_init(&codec->hints, sizeof(struct hda_hint), 32);
         snd_array_init(&codec->user_pins, sizeof(struct hda_pincfg), 16);
 
         return 0;
@@ -306,26 +312,81 @@ static ssize_t init_verbs_store(struct device *dev,
         return count;
 }
 
+static struct hda_hint *get_hint(struct hda_codec *codec, const char *key)
+{
+        int i;
+
+        for (i = 0; i < codec->hints.used; i++) {
+                struct hda_hint *hint = snd_array_elem(&codec->hints, i);
+                if (!strcmp(hint->key, key))
+                        return hint;
+        }
+        return NULL;
+}
+
+static void remove_trail_spaces(char *str)
+{
+        char *p;
+        if (!*str)
+                return;
+        p = str + strlen(str) - 1;
+        for (; isspace(*p); p--) {
+                *p = 0;
+                if (p == str)
+                        return;
+        }
+}
+
+#define MAX_HINTS       1024
+
 static ssize_t hints_store(struct device *dev,
                            struct device_attribute *attr,
                            const char *buf, size_t count)
 {
         struct snd_hwdep *hwdep = dev_get_drvdata(dev);
         struct hda_codec *codec = hwdep->private_data;
-        char *p;
-        char **hint;
+        char *key, *val;
+        struct hda_hint *hint;
 
-        if (!*buf || isspace(*buf) || *buf == '#' || *buf == '\n')
+        while (isspace(*buf))
+                buf++;
+        if (!*buf || *buf == '#' || *buf == '\n')
                 return count;
-        p = kstrndup_noeol(buf, 1024);
-        if (!p)
+        if (*buf == '=')
+                return -EINVAL;
+        key = kstrndup_noeol(buf, 1024);
+        if (!key)
                 return -ENOMEM;
-        hint = snd_array_new(&codec->hints);
+        /* extract key and val */
+        val = strchr(key, '=');
+        if (!val) {
+                kfree(key);
+                return -EINVAL;
+        }
+        *val++ = 0;
+        while (isspace(*val))
+                val++;
+        remove_trail_spaces(key);
+        remove_trail_spaces(val);
+        hint = get_hint(codec, key);
+        if (hint) {
+                /* replace */
+                kfree(hint->key);
+                hint->key = key;
+                hint->val = val;
+                return count;
+        }
+        /* allocate a new hint entry */
+        if (codec->hints.used >= MAX_HINTS)
+                hint = NULL;
+        else
+                hint = snd_array_new(&codec->hints);
         if (!hint) {
-                kfree(p);
+                kfree(key);
                 return -ENOMEM;
         }
-        *hint = p;
+        hint->key = key;
+        hint->val = val;
         return count;
 }
 
@@ -428,4 +489,29 @@ int snd_hda_hwdep_add_sysfs(struct hda_codec *codec)
         return 0;
 }
 
+/*
+ * Look for hint string
+ */
+const char *snd_hda_get_hint(struct hda_codec *codec, const char *key)
+{
+        struct hda_hint *hint = get_hint(codec, key);
+        return hint ? hint->val : NULL;
+}
+EXPORT_SYMBOL_HDA(snd_hda_get_hint);
+
+int snd_hda_get_bool_hint(struct hda_codec *codec, const char *key)
+{
+        const char *p = snd_hda_get_hint(codec, key);
+        if (!p || !*p)
+                return -ENOENT;
+        switch (toupper(*p)) {
+        case 'T': /* true */
+        case 'Y': /* yes */
+        case '1':
+                return 1;
+        }
+        return 0;
+}
+EXPORT_SYMBOL_HDA(snd_hda_get_bool_hint);
+
 #endif /* CONFIG_SND_HDA_RECONFIG */