// SPDX-License-Identifier: GPL-2.0 /* * Presonus Studio 1810c driver for ALSA * Copyright (C) 2019 Nick Kossifidis <[email protected]> * * Based on reverse engineering of the communication protocol * between the windows driver / Univeral Control (UC) program * and the device, through usbmon. * * For now this bypasses the mixer, with all channels split, * so that the software can mix with greater flexibility. * It also adds controls for the 4 buttons on the front of * the device. */ #include <linux/usb.h> #include <linux/usb/audio-v2.h> #include <linux/slab.h> #include <sound/core.h> #include <sound/control.h> #include "usbaudio.h" #include "mixer.h" #include "mixer_quirks.h" #include "helper.h" #include "mixer_s1810c.h" #define SC1810C_CMD_REQ … #define SC1810C_CMD_REQTYPE … #define SC1810C_CMD_F1 … #define SC1810C_CMD_F2 … /* * DISCLAIMER: These are just guesses based on the * dumps I got. * * It seems like a selects between * device (0), mixer (0x64) and output (0x65) * * For mixer (0x64): * * b selects an input channel (see below). * * c selects an output channel pair (see below). * * d selects left (0) or right (1) of that pair. * * e 0-> disconnect, 0x01000000-> connect, * 0x0109-> used for stereo-linking channels, * e is also used for setting volume levels * in which case b is also set so I guess * this way it is possible to set the volume * level from the specified input to the * specified output. * * IN Channels: * 0 - 7 Mic/Inst/Line (Analog inputs) * 8 - 9 S/PDIF * 10 - 17 ADAT * 18 - 35 DAW (Inputs from the host) * * OUT Channels (pairs): * 0 -> Main out * 1 -> Line1/2 * 2 -> Line3/4 * 3 -> S/PDIF * 4 -> ADAT? * * For device (0): * * b and c are not used, at least not on the * dumps I got. * * d sets the control id to be modified * (see below). * * e sets the setting for that control. * (so for the switches I was interested * in it's 0/1) * * For output (0x65): * * b is the output channel (see above). * * c is zero. * * e I guess the same as with mixer except 0x0109 * which I didn't see in my dumps. * * The two fixed fields have the same values for * mixer and output but a different set for device. */ struct s1810c_ctl_packet { … }; #define SC1810C_CTL_LINE_SW … #define SC1810C_CTL_MUTE_SW … #define SC1810C_CTL_AB_SW … #define SC1810C_CTL_48V_SW … #define SC1810C_SET_STATE_REQ … #define SC1810C_SET_STATE_REQTYPE … #define SC1810C_SET_STATE_F1 … #define SC1810C_SET_STATE_F2 … #define SC1810C_GET_STATE_REQ … #define SC1810C_GET_STATE_REQTYPE … #define SC1810C_GET_STATE_F1 … #define SC1810C_GET_STATE_F2 … #define SC1810C_STATE_F1_IDX … #define SC1810C_STATE_F2_IDX … /* * This packet includes mixer volumes and * various other fields, it's an extended * version of ctl_packet, with a and b * being zero and different f1/f2. */ struct s1810c_state_packet { … }; #define SC1810C_STATE_48V_SW … #define SC1810C_STATE_LINE_SW … #define SC1810C_STATE_MUTE_SW … #define SC1810C_STATE_AB_SW … struct s1810_mixer_state { … }; static int snd_s1810c_send_ctl_packet(struct usb_device *dev, u32 a, u32 b, u32 c, u32 d, u32 e) { … } /* * When opening Universal Control the program periodically * sends and receives state packets for syncinc state between * the device and the host. * * Note that if we send only the request to get data back we'll * get an error, we need to first send an empty state packet and * then ask to receive a filled. Their seqnumbers must also match. */ static int snd_sc1810c_get_status_field(struct usb_device *dev, u32 *field, int field_idx, uint16_t *seqnum) { … } /* * This is what I got when bypassing the mixer with * all channels split. I'm not 100% sure of what's going * on, I could probably clean this up based on my observations * but I prefer to keep the same behavior as the windows driver. */ static int snd_s1810c_init_mixer_maps(struct snd_usb_audio *chip) { … } /* * Sync state with the device and retrieve the requested field, * whose index is specified in (kctl->private_value & 0xFF), * from the received fields array. */ static int snd_s1810c_get_switch_state(struct usb_mixer_interface *mixer, struct snd_kcontrol *kctl, u32 *state) { … } /* * Send a control packet to the device for the control id * specified in (kctl->private_value >> 8) with value * specified in (kctl->private_value >> 16). */ static int snd_s1810c_set_switch_state(struct usb_mixer_interface *mixer, struct snd_kcontrol *kctl) { … } /* Generic get/set/init functions for switch controls */ static int snd_s1810c_switch_get(struct snd_kcontrol *kctl, struct snd_ctl_elem_value *ctl_elem) { … } static int snd_s1810c_switch_set(struct snd_kcontrol *kctl, struct snd_ctl_elem_value *ctl_elem) { … } static int snd_s1810c_switch_init(struct usb_mixer_interface *mixer, const struct snd_kcontrol_new *new_kctl) { … } static int snd_s1810c_line_sw_info(struct snd_kcontrol *kctl, struct snd_ctl_elem_info *uinfo) { … } static const struct snd_kcontrol_new snd_s1810c_line_sw = …; static const struct snd_kcontrol_new snd_s1810c_mute_sw = …; static const struct snd_kcontrol_new snd_s1810c_48v_sw = …; static int snd_s1810c_ab_sw_info(struct snd_kcontrol *kctl, struct snd_ctl_elem_info *uinfo) { … } static const struct snd_kcontrol_new snd_s1810c_ab_sw = …; static void snd_sc1810_mixer_state_free(struct usb_mixer_interface *mixer) { … } /* Entry point, called from mixer_quirks.c */ int snd_sc1810_init_mixer(struct usb_mixer_interface *mixer) { … }
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