[PATCH v2] ALSA: line6: add hw monitor volume control for POD HD500

From: Vasily Khoruzhick
Date: Sat May 23 2020 - 13:50:55 EST


Add hw monitor volume control for POD HD500. The same change may
work for HD500X but I don't have it to test.

Signed-off-by: Vasily Khoruzhick <anarsoul@xxxxxxxxx>
---
v2: clamp volume value to [0, ARRAY_SIZE() -1] in
podhd_set_monitor_level()

sound/usb/line6/driver.c | 3 +-
sound/usb/line6/driver.h | 4 ++
sound/usb/line6/podhd.c | 124 ++++++++++++++++++++++++++++++++++++++-
3 files changed, 129 insertions(+), 2 deletions(-)

diff --git a/sound/usb/line6/driver.c b/sound/usb/line6/driver.c
index 7629116f570e..597a36c0a51d 100644
--- a/sound/usb/line6/driver.c
+++ b/sound/usb/line6/driver.c
@@ -97,7 +97,7 @@ static void line6_stop_listen(struct usb_line6 *line6)
/*
Send raw message in pieces of wMaxPacketSize bytes.
*/
-static int line6_send_raw_message(struct usb_line6 *line6, const char *buffer,
+int line6_send_raw_message(struct usb_line6 *line6, const char *buffer,
int size)
{
int i, done = 0;
@@ -132,6 +132,7 @@ static int line6_send_raw_message(struct usb_line6 *line6, const char *buffer,

return done;
}
+EXPORT_SYMBOL(line6_send_raw_message);

/*
Notification of completion of asynchronous request transmission.
diff --git a/sound/usb/line6/driver.h b/sound/usb/line6/driver.h
index 1a4e3700c80c..62c686bed0ca 100644
--- a/sound/usb/line6/driver.h
+++ b/sound/usb/line6/driver.h
@@ -108,6 +108,8 @@ enum {
LINE6_CAP_CONTROL_MIDI = 1 << 4,
/* device provides low-level information */
LINE6_CAP_CONTROL_INFO = 1 << 5,
+ /* device provides hardware monitoring volume control */
+ LINE6_CAP_HWMON_CTL = 1 << 6,
};

/*
@@ -185,6 +187,8 @@ extern int line6_read_data(struct usb_line6 *line6, unsigned address,
void *data, unsigned datalen);
extern int line6_read_serial_number(struct usb_line6 *line6,
u32 *serial_number);
+extern int line6_send_raw_message(struct usb_line6 *line6,
+ const char *buffer, int size);
extern int line6_send_raw_message_async(struct usb_line6 *line6,
const char *buffer, int size);
extern int line6_send_sysex_message(struct usb_line6 *line6,
diff --git a/sound/usb/line6/podhd.c b/sound/usb/line6/podhd.c
index e39dc85c355a..7cc2f1540c7c 100644
--- a/sound/usb/line6/podhd.c
+++ b/sound/usb/line6/podhd.c
@@ -11,6 +11,7 @@
#include <linux/slab.h>
#include <linux/module.h>
#include <sound/core.h>
+#include <sound/control.h>
#include <sound/pcm.h>

#include "driver.h"
@@ -37,6 +38,9 @@ struct usb_line6_podhd {

/* Firmware version */
int firmware_version;
+
+ /* Monitor level */
+ int monitor_level;
};

#define line6_to_podhd(x) container_of(x, struct usb_line6_podhd, line6)
@@ -250,6 +254,115 @@ static void podhd_disconnect(struct usb_line6 *line6)
}
}

+static const unsigned int float_zero_to_one_lookup[] = {
+0x00000000, 0x3C23D70A, 0x3CA3D70A, 0x3CF5C28F, 0x3D23D70A, 0x3D4CCCCD,
+0x3D75C28F, 0x3D8F5C29, 0x3DA3D70A, 0x3DB851EC, 0x3DCCCCCD, 0x3DE147AE,
+0x3DF5C28F, 0x3E051EB8, 0x3E0F5C29, 0x3E19999A, 0x3E23D70A, 0x3E2E147B,
+0x3E3851EC, 0x3E428F5C, 0x3E4CCCCD, 0x3E570A3D, 0x3E6147AE, 0x3E6B851F,
+0x3E75C28F, 0x3E800000, 0x3E851EB8, 0x3E8A3D71, 0x3E8F5C29, 0x3E947AE1,
+0x3E99999A, 0x3E9EB852, 0x3EA3D70A, 0x3EA8F5C3, 0x3EAE147B, 0x3EB33333,
+0x3EB851EC, 0x3EBD70A4, 0x3EC28F5C, 0x3EC7AE14, 0x3ECCCCCD, 0x3ED1EB85,
+0x3ED70A3D, 0x3EDC28F6, 0x3EE147AE, 0x3EE66666, 0x3EEB851F, 0x3EF0A3D7,
+0x3EF5C28F, 0x3EFAE148, 0x3F000000, 0x3F028F5C, 0x3F051EB8, 0x3F07AE14,
+0x3F0A3D71, 0x3F0CCCCD, 0x3F0F5C29, 0x3F11EB85, 0x3F147AE1, 0x3F170A3D,
+0x3F19999A, 0x3F1C28F6, 0x3F1EB852, 0x3F2147AE, 0x3F23D70A, 0x3F266666,
+0x3F28F5C3, 0x3F2B851F, 0x3F2E147B, 0x3F30A3D7, 0x3F333333, 0x3F35C28F,
+0x3F3851EC, 0x3F3AE148, 0x3F3D70A4, 0x3F400000, 0x3F428F5C, 0x3F451EB8,
+0x3F47AE14, 0x3F4A3D71, 0x3F4CCCCD, 0x3F4F5C29, 0x3F51EB85, 0x3F547AE1,
+0x3F570A3D, 0x3F59999A, 0x3F5C28F6, 0x3F5EB852, 0x3F6147AE, 0x3F63D70A,
+0x3F666666, 0x3F68F5C3, 0x3F6B851F, 0x3F6E147B, 0x3F70A3D7, 0x3F733333,
+0x3F75C28F, 0x3F7851EC, 0x3F7AE148, 0x3F7D70A4, 0x3F800000
+};
+
+static void podhd_set_monitor_level(struct usb_line6_podhd *podhd, int value)
+{
+ unsigned int fl;
+ static const unsigned char msg[16] = {
+ /* Chunk is 0xc bytes (without first word) */
+ 0x0c, 0x00,
+ /* First chunk in the message */
+ 0x01, 0x00,
+ /* Message size is 2 4-byte words */
+ 0x02, 0x00,
+ /* Unknown */
+ 0x04, 0x41,
+ /* Unknown */
+ 0x04, 0x00, 0x13, 0x00,
+ /* Volume, LE float32, 0.0 - 1.0 */
+ 0x00, 0x00, 0x00, 0x00
+ };
+ unsigned char *buf;
+
+ buf = kmalloc(sizeof(msg), GFP_ATOMIC);
+ memcpy(buf, msg, sizeof(msg));
+
+ if (value < 0)
+ value = 0;
+
+ if (value >= ARRAY_SIZE(float_zero_to_one_lookup))
+ value = ARRAY_SIZE(float_zero_to_one_lookup) - 1;
+
+ fl = float_zero_to_one_lookup[value];
+
+ buf[12] = (fl >> 0) & 0xff;
+ buf[13] = (fl >> 8) & 0xff;
+ buf[14] = (fl >> 16) & 0xff;
+ buf[15] = (fl >> 24) & 0xff;
+
+ line6_send_raw_message(&podhd->line6, buf, sizeof(msg));
+ kfree(buf);
+
+ podhd->monitor_level = value;
+}
+
+/* control info callback */
+static int snd_podhd_control_monitor_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 = 0;
+ uinfo->value.integer.max = 100;
+ uinfo->value.integer.step = 1;
+ return 0;
+}
+
+/* control get callback */
+static int snd_podhd_control_monitor_get(struct snd_kcontrol *kcontrol,
+ struct snd_ctl_elem_value *ucontrol)
+{
+ struct snd_line6_pcm *line6pcm = snd_kcontrol_chip(kcontrol);
+ struct usb_line6_podhd *podhd = line6_to_podhd(line6pcm->line6);
+
+ ucontrol->value.integer.value[0] = podhd->monitor_level;
+ return 0;
+}
+
+/* control put callback */
+static int snd_podhd_control_monitor_put(struct snd_kcontrol *kcontrol,
+ struct snd_ctl_elem_value *ucontrol)
+{
+ struct snd_line6_pcm *line6pcm = snd_kcontrol_chip(kcontrol);
+ struct usb_line6_podhd *podhd = line6_to_podhd(line6pcm->line6);
+
+ if (ucontrol->value.integer.value[0] == podhd->monitor_level)
+ return 0;
+
+ podhd_set_monitor_level(podhd, ucontrol->value.integer.value[0]);
+ return 1;
+}
+
+/* control definition */
+static const struct snd_kcontrol_new podhd_control_monitor = {
+ .iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+ .name = "Monitor Playback Volume",
+ .index = 0,
+ .access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
+ .info = snd_podhd_control_monitor_info,
+ .get = snd_podhd_control_monitor_get,
+ .put = snd_podhd_control_monitor_put
+};
+
/*
Try to init POD HD device.
*/
@@ -298,6 +411,15 @@ static int podhd_init(struct usb_line6 *line6,
return err;
}

+ if (pod->line6.properties->capabilities & LINE6_CAP_HWMON_CTL) {
+ podhd_set_monitor_level(pod, 100);
+ err = snd_ctl_add(line6->card,
+ snd_ctl_new1(&podhd_control_monitor,
+ line6->line6pcm));
+ if (err < 0)
+ return err;
+ }
+
if (!(pod->line6.properties->capabilities & LINE6_CAP_CONTROL_INFO)) {
/* register USB audio system directly */
return snd_card_register(line6->card);
@@ -354,7 +476,7 @@ static const struct line6_properties podhd_properties_table[] = {
.id = "PODHD500",
.name = "POD HD500",
.capabilities = LINE6_CAP_PCM | LINE6_CAP_CONTROL
- | LINE6_CAP_HWMON,
+ | LINE6_CAP_HWMON | LINE6_CAP_HWMON_CTL,
.altsetting = 1,
.ctrl_if = 1,
.ep_ctrl_r = 0x81,
--
2.26.2