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https://github.com/brain-hackers/linux-brain.git
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11785ef532
Thee USB Audio Class 3 (UAC3) introduces Power Domains as a new feature to let a host turn individual parts of an audio function to different power states via USB requests. This lets the device get to know a bit amore about what the host is up to in order to optimize power consumption efficiently. The Power Domains are optional for UAC3 configuration but all UAC3 devices shall include at least one BADD configuration where the support for Power Domains is compulsory. This patch adds a set of features/helpers to parse these power domains and change their status. Signed-off-by: Jorge Sanjuan <jorge.sanjuan@codethink.co.uk> Signed-off-by: Takashi Iwai <tiwai@suse.de>
105 lines
2.4 KiB
C
105 lines
2.4 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* UAC3 Power Domain state management functions
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*/
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#include <linux/slab.h>
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#include <linux/usb.h>
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#include <linux/usb/audio.h>
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#include <linux/usb/audio-v2.h>
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#include <linux/usb/audio-v3.h>
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#include "usbaudio.h"
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#include "helper.h"
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#include "power.h"
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struct snd_usb_power_domain *
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snd_usb_find_power_domain(struct usb_host_interface *ctrl_iface,
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unsigned char id)
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{
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struct snd_usb_power_domain *pd;
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void *p;
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pd = kzalloc(sizeof(*pd), GFP_KERNEL);
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if (!pd)
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return NULL;
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p = NULL;
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while ((p = snd_usb_find_csint_desc(ctrl_iface->extra,
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ctrl_iface->extralen,
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p, UAC3_POWER_DOMAIN)) != NULL) {
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struct uac3_power_domain_descriptor *pd_desc = p;
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int i;
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for (i = 0; i < pd_desc->bNrEntities; i++) {
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if (pd_desc->baEntityID[i] == id) {
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pd->pd_id = pd_desc->bPowerDomainID;
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pd->pd_d1d0_rec =
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le16_to_cpu(pd_desc->waRecoveryTime1);
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pd->pd_d2d0_rec =
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le16_to_cpu(pd_desc->waRecoveryTime2);
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return pd;
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}
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}
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}
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kfree(pd);
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return NULL;
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}
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int snd_usb_power_domain_set(struct snd_usb_audio *chip,
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struct snd_usb_power_domain *pd,
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unsigned char state)
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{
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struct usb_device *dev = chip->dev;
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unsigned char current_state;
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int err, idx;
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idx = snd_usb_ctrl_intf(chip) | (pd->pd_id << 8);
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err = snd_usb_ctl_msg(chip->dev, usb_rcvctrlpipe(chip->dev, 0),
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UAC2_CS_CUR,
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USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_IN,
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UAC3_AC_POWER_DOMAIN_CONTROL << 8, idx,
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¤t_state, sizeof(current_state));
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if (err < 0) {
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dev_err(&dev->dev, "Can't get UAC3 power state for id %d\n",
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pd->pd_id);
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return err;
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}
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if (current_state == state) {
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dev_dbg(&dev->dev, "UAC3 power domain id %d already in state %d\n",
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pd->pd_id, state);
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return 0;
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}
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err = snd_usb_ctl_msg(chip->dev, usb_sndctrlpipe(chip->dev, 0), UAC2_CS_CUR,
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USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_OUT,
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UAC3_AC_POWER_DOMAIN_CONTROL << 8, idx,
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&state, sizeof(state));
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if (err < 0) {
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dev_err(&dev->dev, "Can't set UAC3 power state to %d for id %d\n",
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state, pd->pd_id);
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return err;
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}
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if (state == UAC3_PD_STATE_D0) {
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switch (current_state) {
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case UAC3_PD_STATE_D2:
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udelay(pd->pd_d2d0_rec * 50);
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break;
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case UAC3_PD_STATE_D1:
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udelay(pd->pd_d1d0_rec * 50);
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break;
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default:
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return -EINVAL;
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}
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}
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dev_dbg(&dev->dev, "UAC3 power domain id %d change to state %d\n",
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pd->pd_id, state);
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return 0;
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}
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