ALSA: scarlett2: Add minimum firmware version check

Early firmware for the Scarlett Gen 4 devices has sufficient
differences that it is better to enforce a minimum firmware version
than to try and work around those differences. Add a minimum firmware
version field to the device info struct, and display a message if the
firmware version is too old. Only create the Firmware Version and MSD
(optional) controls in this case.

Signed-off-by: Geoffrey D. Bennett <g@b4.vu>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://lore.kernel.org/r/5455a7e54bda81556066abd7f761b10e9c5f8a16.1703612638.git.g@b4.vu

diff --git a/sound/usb/mixer_scarlett2.c b/sound/usb/mixer_scarlett2.c
index a24fd6e867ed86390a38e765044f796719a087c2..f1c9f6b022ce51d5a70077bfec392aa2a56b1b34 100644 (file)
--- a/sound/usb/mixer_scarlett2.c
+++ b/sound/usb/mixer_scarlett2.c
@@ -660,6 +660,9 @@ struct scarlett2_device_info {
        /* which set of configuration parameters the device uses */
        const struct scarlett2_config_set *config_set;
 
+       /* minimum firmware version required */
+       u16 min_firmware_version;
+
        /* support for main/alt speaker switching */
        u8 has_speaker_switching;
 
@@ -2352,6 +2355,45 @@ static int scarlett2_add_firmware_version_ctl(
                                     0, 0, "Firmware Version", NULL);
 }
 
+/*** Minimum Firmware Version Control ***/
+
+static int scarlett2_min_firmware_version_ctl_get(
+       struct snd_kcontrol *kctl,
+       struct snd_ctl_elem_value *ucontrol)
+{
+       struct usb_mixer_elem_info *elem = kctl->private_data;
+       struct scarlett2_data *private = elem->head.mixer->private_data;
+
+       ucontrol->value.integer.value[0] = private->info->min_firmware_version;
+
+       return 0;
+}
+
+static int scarlett2_min_firmware_version_ctl_info(
+       struct snd_kcontrol *kctl,
+       struct snd_ctl_elem_info *uinfo)
+{
+       uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
+       uinfo->count = 1;
+
+       return 0;
+}
+
+static const struct snd_kcontrol_new scarlett2_min_firmware_version_ctl = {
+       .iface = SNDRV_CTL_ELEM_IFACE_CARD,
+       .access = SNDRV_CTL_ELEM_ACCESS_READ,
+       .name = "",
+       .info = scarlett2_min_firmware_version_ctl_info,
+       .get  = scarlett2_min_firmware_version_ctl_get
+};
+
+static int scarlett2_add_min_firmware_version_ctl(
+       struct usb_mixer_interface *mixer)
+{
+       return scarlett2_add_new_ctl(mixer, &scarlett2_min_firmware_version_ctl,
+                                    0, 0, "Minimum Firmware Version", NULL);
+}
+
 /*** Sync Control ***/
 
 /* Update sync control after receiving notification that the status
@@ -6061,6 +6103,7 @@ static int scarlett2_get_flash_segment_nums(struct usb_mixer_interface *mixer)
 static int scarlett2_read_configs(struct usb_mixer_interface *mixer)
 {
        struct scarlett2_data *private = mixer->private_data;
+       const struct scarlett2_device_info *info = private->info;
        int err, i;
 
        if (scarlett2_has_config_item(private, SCARLETT2_CONFIG_MSD_SWITCH)) {
@@ -6069,12 +6112,22 @@ static int scarlett2_read_configs(struct usb_mixer_interface *mixer)
                        1, &private->msd_switch);
                if (err < 0)
                        return err;
+       }
 
-               /* no other controls are created if MSD mode is on */
-               if (private->msd_switch)
-                       return 0;
+       if (private->firmware_version < info->min_firmware_version) {
+               usb_audio_err(mixer->chip,
+                             "Focusrite %s firmware version %d is too old; "
+                             "need %d",
+                             private->series_name,
+                             private->firmware_version,
+                             info->min_firmware_version);
+               return 0;
        }
 
+       /* no other controls are created if MSD mode is on */
+       if (private->msd_switch)
+               return 0;
+
        err = scarlett2_update_input_level(mixer);
        if (err < 0)
                return err;
@@ -6595,6 +6648,11 @@ static int snd_scarlett2_controls_create(
        if (err < 0)
                return err;
 
+       /* Add minimum firmware version control */
+       err = scarlett2_add_min_firmware_version_ctl(mixer);
+       if (err < 0)
+               return err;
+
        /* Read volume levels and controls from the interface */
        err = scarlett2_read_configs(mixer);
        if (err < 0)
@@ -6605,8 +6663,11 @@ static int snd_scarlett2_controls_create(
        if (err < 0)
                return err;
 
-       /* If MSD mode is enabled, don't create any other controls */
-       if (private->msd_switch)
+       /* If MSD mode is enabled, or if the firmware version is too
+        * old, don't create any other controls
+        */
+       if (private->msd_switch ||
+           private->firmware_version < private->info->min_firmware_version)
                return 0;
 
        /* Create the analogue output controls */