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authorMark Brown <broonie@opensource.wolfsonmicro.com>2010-03-17 18:07:12 +0000
committerMark Brown <broonie@opensource.wolfsonmicro.com>2010-03-17 18:10:46 +0000
commitebb812cb8df48e299b3d4ab75cbb0042384ef70d (patch)
tree186de489bb17366d66eb5fb4123501ccbcbd8bbc /sound/core
parent1c6e555c3a66af29a51690748ca54314e62c16d5 (diff)
ALSA: Add support for key reporting via the jack interface
Some devices provide support for detection of a small number of buttons on their jacks. One common implementation provides a single button, implemented by shorting the microphone to ground and detected along with microphone presence detection by detecting varying current draws on the microphone bias signal. Provide support for up to three buttons via the jack interface. These default to reporting BTN_n but an API is provided to allow these to be remapped to other keys by the machine driver where it knows what the keys are. More keys can be added with ease if required. This is only intended to support simple accessory button designs. If the interface is limiting then either creating a child device for the accessory or accessing the input device in the jack directly is recommended. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Diffstat (limited to 'sound/core')
-rw-r--r--sound/core/jack.c60
1 files changed, 59 insertions, 1 deletions
diff --git a/sound/core/jack.c b/sound/core/jack.c
index f6f091f2b38..3813e7b04d0 100644
--- a/sound/core/jack.c
+++ b/sound/core/jack.c
@@ -55,7 +55,7 @@ static int snd_jack_dev_register(struct snd_device *device)
{
struct snd_jack *jack = device->device_data;
struct snd_card *card = device->card;
- int err;
+ int err, i;
snprintf(jack->name, sizeof(jack->name), "%s %s",
card->shortname, jack->id);
@@ -65,6 +65,19 @@ static int snd_jack_dev_register(struct snd_device *device)
if (!jack->input_dev->dev.parent)
jack->input_dev->dev.parent = snd_card_get_device_link(card);
+ /* Add capabilities for any keys that are enabled */
+ for (i = 0; i < ARRAY_SIZE(jack->key); i++) {
+ int testbit = SND_JACK_BTN_0 >> i;
+
+ if (!(jack->type & testbit))
+ continue;
+
+ if (!jack->key[i])
+ jack->key[i] = BTN_0 + i;
+
+ input_set_capability(jack->input_dev, EV_KEY, jack->key[i]);
+ }
+
err = input_register_device(jack->input_dev);
if (err == 0)
jack->registered = 1;
@@ -151,6 +164,43 @@ void snd_jack_set_parent(struct snd_jack *jack, struct device *parent)
EXPORT_SYMBOL(snd_jack_set_parent);
/**
+ * snd_jack_set_key - Set a key mapping on a jack
+ *
+ * @jack: The jack to configure
+ * @type: Jack report type for this key
+ * @keytype: Input layer key type to be reported
+ *
+ * Map a SND_JACK_BTN_ button type to an input layer key, allowing
+ * reporting of keys on accessories via the jack abstraction. If no
+ * mapping is provided but keys are enabled in the jack type then
+ * BTN_n numeric buttons will be reported.
+ *
+ * Note that this is intended to be use by simple devices with small
+ * numbers of keys that can be reported. It is also possible to
+ * access the input device directly - devices with complex input
+ * capabilities on accessories should consider doing this rather than
+ * using this abstraction.
+ *
+ * This function may only be called prior to registration of the jack.
+ */
+int snd_jack_set_key(struct snd_jack *jack, enum snd_jack_types type,
+ int keytype)
+{
+ int key = fls(SND_JACK_BTN_0) - fls(type);
+
+ WARN_ON(jack->registered);
+
+ if (!keytype || key >= ARRAY_SIZE(jack->key))
+ return -EINVAL;
+
+ jack->type |= type;
+ jack->key[key] = keytype;
+
+ return 0;
+}
+EXPORT_SYMBOL(snd_jack_set_key);
+
+/**
* snd_jack_report - Report the current status of a jack
*
* @jack: The jack to report status for
@@ -163,6 +213,14 @@ void snd_jack_report(struct snd_jack *jack, int status)
if (!jack)
return;
+ for (i = 0; i < ARRAY_SIZE(jack->key); i++) {
+ int testbit = SND_JACK_BTN_0 >> i;
+
+ if (jack->type & testbit)
+ input_report_key(jack->input_dev, jack->key[i],
+ status & testbit);
+ }
+
for (i = 0; i < ARRAY_SIZE(jack_switch_types); i++) {
int testbit = 1 << i;
if (jack->type & testbit)