[alsa-devel] [PATCH] ALSA: jack: create jack kcontrols for every jack input device
Liam Girdwood
liam.r.girdwood at intel.com
Thu Mar 19 10:02:22 CET 2015
On Thu, 2015-03-19 at 08:53 +0000, Liam Girdwood wrote:
> On Thu, 2015-03-19 at 16:40 +0800, Jie Yang wrote:
> > From: Liam Girdwood <liam.r.girdwood at linux.intel.com>
> >
>
> I cant claim much credit for this as it's mostly your work now :)
>
> Liam
Sorry, I had more comments below... also got one more new one
>
> > Currently the ALSA jack core registers only input devices for each jack
> > registered. These jack input devices are not readable by userspace devices
> > that run as non root.
> >
> > This patch adds support for additionally registering jack kcontrol devices
> > for every input jack registered. This allows non root userspace to read
> > jack status.
> >
> > Signed-off-by: Liam Girdwood <liam.r.girdwood at linux.intel.com>
> > Modified-by: Jie Yang <yang.jie at intel.com>
> > Signed-off-by: Jie Yang <yang.jie at intel.com>
> > Reveiwed-by: Mark Brown <broonie at kernel.org>
> > ---
> > include/sound/control.h | 2 ++
> > include/sound/jack.h | 2 ++
> > sound/core/jack.c | 89 +++++++++++++++++++++++++++++++++++++++++++++++--
> > 3 files changed, 91 insertions(+), 2 deletions(-)
> > mode change 100644 => 100755 sound/core/jack.c
> >
> > diff --git a/include/sound/control.h b/include/sound/control.h
> > index 75f3054..023b70a 100644
> > --- a/include/sound/control.h
> > +++ b/include/sound/control.h
> > @@ -66,6 +66,7 @@ struct snd_kcontrol_volatile {
> >
> > struct snd_kcontrol {
> > struct list_head list; /* list of controls */
> > + struct list_head jack_list; /* list of controls belong to the same jack*/
> > struct snd_ctl_elem_id id;
> > unsigned int count; /* count of same elements */
> > snd_kcontrol_info_t *info;
> > @@ -75,6 +76,7 @@ struct snd_kcontrol {
> > snd_kcontrol_tlv_rw_t *c;
> > const unsigned int *p;
> > } tlv;
> > + unsigned int jack_bit_idx; /*the corresponding jack type bit index */
> > unsigned long private_value;
> > void *private_data;
> > void (*private_free)(struct snd_kcontrol *kcontrol);
> > diff --git a/include/sound/jack.h b/include/sound/jack.h
> > index 2182350..477dcb4 100644
> > --- a/include/sound/jack.h
> > +++ b/include/sound/jack.h
> > @@ -73,6 +73,8 @@ enum snd_jack_types {
> >
> > struct snd_jack {
> > struct input_dev *input_dev;
> > + struct list_head kctl_list;
> > + struct snd_card *card;
> > int registered;
> > int type;
> > const char *id;
> > diff --git a/sound/core/jack.c b/sound/core/jack.c
> > old mode 100644
> > new mode 100755
> > index 8658578..c067b6a
> > --- a/sound/core/jack.c
> > +++ b/sound/core/jack.c
> > @@ -24,6 +24,7 @@
> > #include <linux/module.h>
> > #include <sound/jack.h>
> > #include <sound/core.h>
> > +#include <sound/control.h>
> >
> > static int jack_switch_types[SND_JACK_SWITCH_TYPES] = {
> > SW_HEADPHONE_INSERT,
> > @@ -54,7 +55,13 @@ static int snd_jack_dev_disconnect(struct snd_device *device)
> > static int snd_jack_dev_free(struct snd_device *device)
> > {
> > struct snd_jack *jack = device->device_data;
> > + struct snd_card *card = device->card;
> > + struct snd_kcontrol *kctl;
> >
> > + list_for_each_entry(kctl, &jack->kctl_list, jack_list) {
> > + list_del(&kctl->jack_list);
>
> This is not safe, as we cant iterate over a list when we are removing
> items using list_for_each_entry(). There are other list methods in
> list.h to safely iterate and remove items.
>
> > + snd_ctl_remove(card, kctl);
> > + }
> > if (jack->private_free)
> > jack->private_free(jack);
> >
> > @@ -100,6 +107,63 @@ static int snd_jack_dev_register(struct snd_device *device)
> > return err;
> > }
> >
> > +
> > +/* get the first unused/available index number for the given kctl name */
> > +static int get_available_index(struct snd_card *card, const char *name)
> > +{
> > + struct snd_kcontrol *kctl;
> > + int idx = 0;
> > + int len = strlen(name);
> > +
> > + down_write(&card->controls_rwsem);
I think we are only reading the card state below so we can use
down_read().
> > + next:
> > + list_for_each_entry(kctl, &card->controls, list) {
> > + if (!strncmp(name, kctl->id.name, len) &&
> > + !strcmp(" Jack", kctl->id.name + len) &&
> > + kctl->id.index == idx) {
> > + idx++;
> > + goto next;
>
> Wont continue work here instead of goto ?
>
> > + }
> > + }
> > + up_write(&card->controls_rwsem);
> > + return idx;
> > +}
> > +
> > +static void kctl_private_free(struct snd_kcontrol *kctl)
> > +{
> > + list_del(&kctl->jack_list);
> > +}
> > +
> > +static int snd_jack_new_kctl(struct snd_card *card, struct snd_jack *jack, int type)
> > +{
> > + struct snd_kcontrol *kctl;
> > + int i, err, index, state = 0 /* use 0 for default state ?? */;
> > +
> > + INIT_LIST_HEAD(&jack->kctl_list);
> > + for (i = 0; i < fls(SND_JACK_BTN_0); i++) {
> > + int testbit = 1 << i;
> > + if (type & testbit) {
> > + index = get_available_index(card,jack->id);
> > + kctl = snd_kctl_jack_new(jack->id, index, card);
> > + if (!kctl)
> > + return -ENOMEM;
> > + kctl->private_free = kctl_private_free;
> > + /* use jack_bit_idx for the kctl type bit */
> > + kctl->jack_bit_idx = i;
> > +
>
> This section above could do with some new lines to break the code into
> logical chunks.
>
> > + err = snd_ctl_add(card, kctl);
> > + if (err < 0)
> > + return err;
> > + list_add_tail(&kctl->jack_list, &jack->kctl_list);
> > +
> > + /* set initial jack state */
> > + snd_kctl_jack_report(card, kctl, state & testbit);
> > + }
> > + }
> > +
> > + return 0;
> > +}
> > +
> > /**
> > * snd_jack_new - Create a new jack
> > * @card: the card instance
> > @@ -138,7 +202,7 @@ int snd_jack_new(struct snd_card *card, const char *id, int type,
> > }
> >
> > jack->input_dev->phys = "ALSA";
> > -
> > + jack->card = card;
> > jack->type = type;
> >
> > for (i = 0; i < SND_JACK_SWITCH_TYPES; i++)
> > @@ -150,10 +214,17 @@ int snd_jack_new(struct snd_card *card, const char *id, int type,
> > if (err < 0)
> > goto fail_input;
> >
> > + /* register jack kcontrols */
> > + err = snd_jack_new_kctl(card, jack, type);
> > + if (err < 0)
> > + goto fail_kctl;
> > +
> > *jjack = jack;
> >
> > return 0;
> >
> > +fail_kctl:
> > + snd_device_free(card, jack);
> > fail_input:
> > input_free_device(jack->input_dev);
> > kfree(jack->id);
> > @@ -230,6 +301,7 @@ EXPORT_SYMBOL(snd_jack_set_key);
> > */
> > void snd_jack_report(struct snd_jack *jack, int status)
> > {
> > + struct snd_kcontrol *kctl;
> > int i;
> >
> > if (!jack)
> > @@ -245,13 +317,26 @@ void snd_jack_report(struct snd_jack *jack, int status)
> >
> > for (i = 0; i < ARRAY_SIZE(jack_switch_types); i++) {
> > int testbit = 1 << i;
> > - if (jack->type & testbit)
> > + if (jack->type & testbit) {
> > input_report_switch(jack->input_dev,
> > jack_switch_types[i],
> > status & testbit);
> > + }
> > }
> >
> > input_sync(jack->input_dev);
> > +
> > + for (i = 0; i < fls(SND_JACK_BTN_0); i++) {
> > + int testbit = 1 << i;
> > + if (jack->type & testbit) {
> > + list_for_each_entry(kctl, &jack->kctl_list, jack_list) {
> > + if (kctl->jack_bit_idx == i) {
> > + snd_kctl_jack_report(jack->card, kctl,
> > + status & testbit);
> > + }
> > + }
> > + }
> > + }
> > }
> > EXPORT_SYMBOL(snd_jack_report);
> >
Liam
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