Add a new ALSA control element to watch the current operation mode (MIDI 1.0 or MIDI 2.0). It's a read-only control that reflects the current value of altsetting, and 0 means unused, 1 for MIDI 1.0 (altset 0) and 2 for MIDI 2.0 (altset 1).
Signed-off-by: Takashi Iwai tiwai@suse.de --- Documentation/usb/gadget-testing.rst | 11 +++++++++ drivers/usb/gadget/function/f_midi2.c | 35 +++++++++++++++++++++++++++ 2 files changed, 46 insertions(+)
diff --git a/Documentation/usb/gadget-testing.rst b/Documentation/usb/gadget-testing.rst index 0f3708ae5bc8..1fb181d61322 100644 --- a/Documentation/usb/gadget-testing.rst +++ b/Documentation/usb/gadget-testing.rst @@ -1106,3 +1106,14 @@ On the host:: The access to MIDI 1.0 on altset 0 on the host is supported, and it's translated from/to UMP packets on the gadget. It's bound to only Function Block 0. + +The current operation mode can be observed in ALSA control element +"Operation Mode" for SND_CTL_IFACE_RAWMIDI. For example:: + + $ amixer -c1 contents + numid=1,iface=RAWMIDI,name='Operation Mode' + ; type=INTEGER,access=r--v----,values=1,min=0,max=2,step=0 + : values=2 + +where 0 = unused, 1 = MIDI 1.0 (altset 0), 2 = MIDI 2.0 (altset 1). +The example above shows it's running in 2, i.e. MIDI 2.0. diff --git a/drivers/usb/gadget/function/f_midi2.c b/drivers/usb/gadget/function/f_midi2.c index a368ac51d349..ec9ef15abfea 100644 --- a/drivers/usb/gadget/function/f_midi2.c +++ b/drivers/usb/gadget/function/f_midi2.c @@ -9,6 +9,7 @@ #include <linux/slab.h>
#include <sound/core.h> +#include <sound/control.h> #include <sound/ump.h> #include <sound/ump_msg.h> #include <sound/ump_convert.h> @@ -1450,6 +1451,36 @@ static const struct snd_ump_ops f_midi2_ump_ops = { .drain = f_midi2_ump_drain, };
+/* + * "Operation Mode" control element + */ +static int f_midi2_operation_mode_info(struct snd_kcontrol *kcontrol, + struct snd_ctl_elem_info *uinfo) +{ + uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER; + uinfo->count = 1; + uinfo->value.integer.min = MIDI_OP_MODE_UNSET; + uinfo->value.integer.max = MIDI_OP_MODE_MIDI2; + return 0; +} + +static int f_midi2_operation_mode_get(struct snd_kcontrol *kcontrol, + struct snd_ctl_elem_value *ucontrol) +{ + struct f_midi2 *midi2 = snd_kcontrol_chip(kcontrol); + + ucontrol->value.integer.value[0] = midi2->operation_mode; + return 0; +} + +static const struct snd_kcontrol_new operation_mode_ctl = { + .iface = SNDRV_CTL_ELEM_IFACE_RAWMIDI, + .name = "Operation Mode", + .access = SNDRV_CTL_ELEM_ACCESS_READ | SNDRV_CTL_ELEM_ACCESS_VOLATILE, + .info = f_midi2_operation_mode_info, + .get = f_midi2_operation_mode_get, +}; + /* * ALSA UMP instance creation / deletion */ @@ -1547,6 +1578,10 @@ static int f_midi2_create_card(struct f_midi2 *midi2) id++; }
+ err = snd_ctl_add(card, snd_ctl_new1(&operation_mode_ctl, midi2)); + if (err < 0) + goto error; + err = snd_card_register(card); if (err < 0) goto error;