sound/usb/power.c

Source file repositories/reference/linux-study-clean/sound/usb/power.c

File Facts

System
Linux kernel
Corpus path
sound/usb/power.c
Extension
.c
Size
2585 bytes
Lines
108
Domain
Driver Families
Bucket
sound/usb
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

if (pd_desc->baEntityID[i] == id) {
				pd->pd_id = pd_desc->bPowerDomainID;
				pd->pd_d1d0_rec =
					le16_to_cpu(pd_desc->waRecoveryTime1);
				pd->pd_d2d0_rec =
					le16_to_cpu(pd_desc->waRecoveryTime2);
				pd->ctrl_iface = ctrl_iface;
				return pd;
			}
		}
	}

	kfree(pd);
	return NULL;
}

int snd_usb_power_domain_set(struct snd_usb_audio *chip,
			     struct snd_usb_power_domain *pd,
			     unsigned char state)
{
	struct usb_device *dev = chip->dev;
	unsigned char current_state;
	int err, idx;

	idx = snd_usb_ctrl_intf(pd->ctrl_iface) | (pd->pd_id << 8);

	err = snd_usb_ctl_msg(chip->dev, usb_rcvctrlpipe(chip->dev, 0),
			      UAC2_CS_CUR,
			      USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_IN,
			      UAC3_AC_POWER_DOMAIN_CONTROL << 8, idx,
			      &current_state, sizeof(current_state));
	if (err < 0) {
		dev_err(&dev->dev, "Can't get UAC3 power state for id %d\n",
			pd->pd_id);
		return err;
	}

	if (current_state == state) {
		dev_dbg(&dev->dev, "UAC3 power domain id %d already in state %d\n",
			pd->pd_id, state);
		return 0;
	}

	err = snd_usb_ctl_msg(chip->dev, usb_sndctrlpipe(chip->dev, 0), UAC2_CS_CUR,
			      USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_OUT,
			      UAC3_AC_POWER_DOMAIN_CONTROL << 8, idx,
			      &state, sizeof(state));
	if (err < 0) {
		dev_err(&dev->dev, "Can't set UAC3 power state to %d for id %d\n",
			state, pd->pd_id);
		return err;
	}

	if (state == UAC3_PD_STATE_D0) {
		switch (current_state) {
		case UAC3_PD_STATE_D2:
			udelay(pd->pd_d2d0_rec * 50);
			break;
		case UAC3_PD_STATE_D1:
			udelay(pd->pd_d1d0_rec * 50);
			break;
		default:
			return -EINVAL;
		}
	}

	dev_dbg(&dev->dev, "UAC3 power domain id %d change to state %d\n",
		pd->pd_id, state);

	return 0;
}

Annotation

Implementation Notes