[RFC][PATCH v4 3/4] alsa: jack: add more jack_kctl debugfs nodes

[Hui Wang <hui.wang@canonical.com>]

Adding 4 more debugfs nodes, users could get more information about
the jack_kctl from them:
 - kctl_id, read-only, get jack_kctl->kctl's id
   sound/card0/HeadphoneJack# cat kctl_id
   Headphone Jack

 - mask_bits, read-only, get jack_kctl's events mask_bits
   sound/card0/HeadphoneJack# cat mask_bits
   0x0001 HEADPHONE(0x0001)

 - status, read-only, get jack_kctl's current status
   headphone unplugged:
   sound/card0/HeadphoneJack# cat status
   0x0000
   headphone plugged:
   sound/card0/HeadphoneJack# cat status
   0x0001 HEADPHONE(0x0001)

 - type, read-only, get jack's supported events type
   sound/card0/HeadphoneJack# cat type
   0x0001 HEADPHONE(0x0001)

Signed-off-by: Hui Wang <hui.wang@canonical.com>
---
 sound/core/jack.c | 144 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 144 insertions(+)

diff --git a/sound/core/jack.c b/sound/core/jack.c
index e1d1b26f3a5e..fc49dae887f8 100644
--- a/sound/core/jack.c
+++ b/sound/core/jack.c
@@ -230,6 +230,119 @@ static ssize_t jackin_inject_write(struct file *file,
 	return ret;
 }
 
+static ssize_t jack_kctl_id_read(struct file *file,
+				 char __user *to, size_t count, loff_t *ppos)
+{
+	struct snd_jack_kctl *jack_kctl = file->private_data;
+	char *buf;
+	int len, ret;
+
+	buf = kvzalloc(PAGE_SIZE, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	len = scnprintf(buf, PAGE_SIZE, "%s\n", jack_kctl->kctl->id.name);
+	ret = simple_read_from_buffer(to, count, ppos, buf, len);
+
+	kvfree(buf);
+	return ret;
+}
+
+/* the bit definition is aligned with snd_jack_types in jack.h */
+static const char * const jack_events_name[] = {
+	"HEADPHONE(0x0001)", "MICROPHONE(0x0002)", "LINEOUT(0x0004)",
+	"MECHANICAL(0x0008)", "VIDEOOUT(0x0010)", "LINEIN(0x0020)",
+	"", "", "", "BTN_5(0x0200)", "BTN_4(0x0400)", "BTN_3(0x0800)",
+	"BTN_2(0x1000)", "BTN_1(0x2000)", "BTN_0(0x4000)", "",
+};
+
+static int parse_mask_bits(unsigned int mask_bits, char *s)
+{
+	char *buf;
+	int len, i;
+
+	buf = kvzalloc(PAGE_SIZE, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	len = scnprintf(buf, PAGE_SIZE, "0x%04x", mask_bits);
+
+	for (i = 0; i < 16; i++)
+		if (mask_bits & (1 << i))
+			len += scnprintf(buf + strlen(buf), PAGE_SIZE - strlen(buf),
+					 " %s", jack_events_name[i]);
+
+	len += scnprintf(buf + strlen(buf), PAGE_SIZE - strlen(buf), "\n");
+
+	strcpy(s, buf);
+
+	kvfree(buf);
+
+	return len;
+}
+
+static ssize_t jack_kctl_mask_bits_read(struct file *file,
+					char __user *to, size_t count, loff_t *ppos)
+{
+	struct snd_jack_kctl *jack_kctl = file->private_data;
+	char *buf;
+	int len, ret;
+
+	buf = kvzalloc(PAGE_SIZE, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	len = parse_mask_bits(jack_kctl->mask_bits, buf);
+	ret = simple_read_from_buffer(to, count, ppos, buf, len);
+
+	kvfree(buf);
+	return ret;
+}
+
+static ssize_t jack_kctl_status_read(struct file *file,
+				     char __user *to, size_t count, loff_t *ppos)
+{
+	struct snd_jack_kctl *jack_kctl = file->private_data;
+	char *buf;
+	int len, ret;
+
+	buf = kvzalloc(PAGE_SIZE, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	len = parse_mask_bits(jack_kctl->kctl->private_value, buf);
+	ret = simple_read_from_buffer(to, count, ppos, buf, len);
+
+	kvfree(buf);
+	return ret;
+}
+
+#ifdef CONFIG_SND_JACK_INPUT_DEV
+static ssize_t jack_type_read(struct file *file,
+			      char __user *to, size_t count, loff_t *ppos)
+{
+	struct snd_jack_kctl *jack_kctl = file->private_data;
+	char *buf;
+	int len, ret;
+
+	buf = kvzalloc(PAGE_SIZE, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	len = parse_mask_bits(jack_kctl->jack->type, buf);
+	ret = simple_read_from_buffer(to, count, ppos, buf, len);
+
+	kvfree(buf);
+	return ret;
+}
+
+static const struct file_operations jack_type_fops = {
+	.open = simple_open,
+	.read = jack_type_read,
+	.llseek = default_llseek,
+};
+#endif
+
 static const struct file_operations sw_inject_enable_fops = {
 	.open = simple_open,
 	.read = sw_inject_enable_read,
@@ -243,6 +356,24 @@ static const struct file_operations jackin_inject_fops = {
 	.llseek = default_llseek,
 };
 
+static const struct file_operations jack_kctl_id_fops = {
+	.open = simple_open,
+	.read = jack_kctl_id_read,
+	.llseek = default_llseek,
+};
+
+static const struct file_operations jack_kctl_mask_bits_fops = {
+	.open = simple_open,
+	.read = jack_kctl_mask_bits_read,
+	.llseek = default_llseek,
+};
+
+static const struct file_operations jack_kctl_status_fops = {
+	.open = simple_open,
+	.read = jack_kctl_status_read,
+	.llseek = default_llseek,
+};
+
 /* The substrings in the jack's name but not suitable for folder's name */
 static const char * const dropped_chars[] = {
 	"/", "=", ",", " ",
@@ -282,6 +413,19 @@ static int snd_jack_debugfs_add_inject_node(struct snd_jack *jack,
 	debugfs_create_file("jackin_inject", 0200, jack_kctl->jack_debugfs_root, jack_kctl,
 			    &jackin_inject_fops);
 
+	debugfs_create_file("kctl_id", 0444, jack_kctl->jack_debugfs_root, jack_kctl,
+			    &jack_kctl_id_fops);
+
+	debugfs_create_file("mask_bits", 0444, jack_kctl->jack_debugfs_root, jack_kctl,
+			    &jack_kctl_mask_bits_fops);
+
+	debugfs_create_file("status", 0444, jack_kctl->jack_debugfs_root, jack_kctl,
+			    &jack_kctl_status_fops);
+
+#ifdef CONFIG_SND_JACK_INPUT_DEV
+	debugfs_create_file("type", 0444, jack_kctl->jack_debugfs_root, jack_kctl,
+			    &jack_type_fops);
+#endif
 	return 0;
 }
 #else /* CONFIG_DEBUG_FS */
-- 
2.25.1