drivers/usb/gadget/udc/max3420_udc.c

Source file repositories/reference/linux-study-clean/drivers/usb/gadget/udc/max3420_udc.c

File Facts

System
Linux kernel
Corpus path
drivers/usb/gadget/udc/max3420_udc.c
Extension
.c
Size
30600 bytes
Lines
1331
Domain
Driver Families
Bucket
drivers/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

struct max3420_req {
	struct usb_request usb_req;
	struct list_head queue;
	struct max3420_ep *ep;
};

struct max3420_ep {
	struct usb_ep ep_usb;
	struct max3420_udc *udc;
	struct list_head queue;
	char name[MAX3420_EPNAME_SIZE];
	unsigned int maxpacket;
	spinlock_t lock;
	int halted;
	u32 todo;
	int id;
};

struct max3420_udc {
	struct usb_gadget gadget;
	struct max3420_ep ep[MAX3420_MAX_EPS];
	struct usb_gadget_driver *driver;
	struct task_struct *thread_task;
	int remote_wkp, is_selfpowered;
	bool vbus_active, softconnect;
	struct usb_ctrlrequest setup;
	struct mutex spi_bus_mutex;
	struct max3420_req ep0req;
	struct spi_device *spi;
	struct device *dev;
	spinlock_t lock;
	bool suspended;
	u8 ep0buf[64];
	u32 todo;
};

#define to_max3420_req(r)	container_of((r), struct max3420_req, usb_req)
#define to_max3420_ep(e)	container_of((e), struct max3420_ep, ep_usb)
#define to_udc(g)		container_of((g), struct max3420_udc, gadget)

#define DRIVER_DESC     "MAX3420 USB Device-Mode Driver"
static const char driver_name[] = "max3420-udc";

/* Control endpoint configuration.*/
static const struct usb_endpoint_descriptor ep0_desc = {
	.bEndpointAddress	= USB_DIR_OUT,
	.bmAttributes		= USB_ENDPOINT_XFER_CONTROL,
	.wMaxPacketSize		= cpu_to_le16(MAX3420_EP_MAX_PACKET),
};

static void spi_ack_ctrl(struct max3420_udc *udc)
{
	struct spi_device *spi = udc->spi;
	struct spi_transfer transfer;
	struct spi_message msg;
	u8 txdata[1];

	memset(&transfer, 0, sizeof(transfer));

	spi_message_init(&msg);

	txdata[0] = MAX3420_ACKSTAT;
	transfer.tx_buf = txdata;
	transfer.len = 1;

	spi_message_add_tail(&transfer, &msg);
	spi_sync(spi, &msg);
}

static u8 spi_rd8_ack(struct max3420_udc *udc, u8 reg, int actstat)
{
	struct spi_device *spi = udc->spi;
	struct spi_transfer transfer;
	struct spi_message msg;
	u8 txdata[2], rxdata[2];

	memset(&transfer, 0, sizeof(transfer));

	spi_message_init(&msg);

	txdata[0] = MAX3420_SPI_CMD_RD(reg) | (actstat ? MAX3420_ACKSTAT : 0);
	transfer.tx_buf = txdata;
	transfer.rx_buf = rxdata;
	transfer.len = 2;

	spi_message_add_tail(&transfer, &msg);
	spi_sync(spi, &msg);

	return rxdata[1];
}

Annotation

Implementation Notes