On 10/17/23 15:00, Wesley Cheng wrote: > Some platforms may have support for offloading USB audio devices to a > dedicated audio DSP. Introduce a set of APIs that allow for management of > USB sound card and PCM devices enumerated by the USB SND class driver. > This allows for the ASoC components to be aware of what USB devices are USB devices or USB endpoints? or both? > available for offloading. > +/** > + * struct snd_soc_usb_device > + * @card_idx - sound card index associated with USB device > + * @chip_idx - USB sound chip array index > + * @num_playback - number of playback streams > + * @num_capture - number of capture streams presumably excluding explicit feedback streams? > + **/ > +struct snd_soc_usb_device { > + int card_idx; > + int chip_idx; > + int num_playback; > + int num_capture; > +}; > + > +/** > + * struct snd_soc_usb > + * @list - list head for SND SOC struct list > + * @dev - USB backend device reference > + * @component - reference to ASoC component > + * @connection_status_cb - callback to notify connection events > + * @priv_data - driver data > + **/ > +struct snd_soc_usb { > + struct list_head list; > + struct device *dev; usbdev for consistency with the API below? > + struct snd_soc_component *component; could you use component only and infer the device from component->dev? > + int (*connection_status_cb)(struct snd_soc_usb *usb, > + struct snd_soc_usb_device *sdev, bool connected); > + void *priv_data; > +}; > + > +int snd_soc_usb_connect(struct device *usbdev, struct snd_soc_usb_device *sdev); > +int snd_soc_usb_disconnect(struct device *usbdev, struct snd_soc_usb_device *sdev); > +void *snd_soc_usb_get_priv_data(struct device *usbdev); > + > +struct snd_soc_usb *snd_soc_usb_add_port(struct device *dev, void *priv, struct device *usbdev for consistency ? > + int (*connection_cb)(struct snd_soc_usb *usb, > + struct snd_soc_usb_device *sdev, bool connected)); > +int snd_soc_usb_remove_port(struct device *dev); struct device *usbdev for consistency ? > +struct snd_soc_usb *snd_soc_usb_add_port(struct device *dev, void *priv, > + int (*connection_cb)(struct snd_soc_usb *usb, > + struct snd_soc_usb_device *sdev, bool connected))> +{ > + struct snd_soc_usb *usb; > + > + usb = devm_kzalloc(dev, sizeof(*usb), GFP_KERNEL); > + if (!usb) > + return ERR_PTR(-ENOMEM); > + > + usb->connection_status_cb = connection_cb; > + usb->dev = dev; > + usb->priv_data = priv; > + > + mutex_lock(&ctx_mutex); > + list_add_tail(&usb->list, &usb_ctx_list); > + mutex_unlock(&ctx_mutex); > + > + return usb; > +} > +EXPORT_SYMBOL_GPL(snd_soc_usb_add_port); > + > +/** > + * snd_soc_usb_remove_port() - Remove a USB backend port > + * @dev: USB backend device > + * > + * Remove a USB backend device from USB SND SOC. Memory is freed when USB > + * backend is removed. when the USB backend driver is unbound? > + * > + */ > +int snd_soc_usb_remove_port(struct device *dev) > +{ > + struct snd_soc_usb *ctx, *tmp; > + > + mutex_lock(&ctx_mutex); > + list_for_each_entry_safe(ctx, tmp, &usb_ctx_list, list) { > + if (ctx->dev == dev) { > + list_del(&ctx->list); > + break; > + } > + } > + mutex_unlock(&ctx_mutex); > + > + return 0; can this return void to align with the current trend? > +} > +EXPORT_SYMBOL_GPL(snd_soc_usb_remove_port); > + > +/** > + * snd_soc_usb_connect() - Notification of USB device connection > + * @usbdev: USB bus device > + * @card_idx: USB SND card instance > + * > + * Notify of a new USB SND device connection. The card_idx can be used to > + * handle how the DPCM backend selects, which device to enable USB offloading > + * on. card_idx is not used below, and I don't see how this relates to a notification? > + * > + */ > +int snd_soc_usb_connect(struct device *usbdev, struct snd_soc_usb_device *sdev) > +{ > + struct snd_soc_usb *ctx; > + struct device_node *node; > + > + if (!usbdev) > + return -ENODEV; > + > + node = snd_soc_find_phandle(usbdev); > + if (IS_ERR(node)) > + return -ENODEV; > + > + ctx = snd_soc_find_usb_ctx(node); > + of_node_put(node); > + if (!ctx) > + return -ENODEV; > + > + if (ctx->connection_status_cb) > + ctx->connection_status_cb(ctx, sdev, true); > + > + return 0; > +}