drivers/input/rmi4/rmi_i2c.c

Source file repositories/reference/linux-study-clean/drivers/input/rmi4/rmi_i2c.c

File Facts

System
Linux kernel
Corpus path
drivers/input/rmi4/rmi_i2c.c
Extension
.c
Size
9555 bytes
Lines
389
Domain
Driver Families
Bucket
drivers/input
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 rmi_i2c_xport {
	struct rmi_transport_dev xport;
	struct i2c_client *client;

	struct mutex page_mutex;
	int page;

	u8 *tx_buf;
	size_t tx_buf_size;

	struct regulator_bulk_data supplies[2];
	u32 startup_delay;
};

#define RMI_PAGE_SELECT_REGISTER 0xff
#define RMI_I2C_PAGE(addr) (((addr) >> 8) & 0xff)

/*
 * rmi_set_page - Set RMI page
 * @xport: The pointer to the rmi_transport_dev struct
 * @page: The new page address.
 *
 * RMI devices have 16-bit addressing, but some of the transport
 * implementations (like SMBus) only have 8-bit addressing. So RMI implements
 * a page address at 0xff of every page so we can reliable page addresses
 * every 256 registers.
 *
 * The page_mutex lock must be held when this function is entered.
 *
 * Returns zero on success, non-zero on failure.
 */
static int rmi_set_page(struct rmi_i2c_xport *rmi_i2c, u8 page)
{
	struct i2c_client *client = rmi_i2c->client;
	u8 txbuf[2] = {RMI_PAGE_SELECT_REGISTER, page};
	int retval;

	retval = i2c_master_send(client, txbuf, sizeof(txbuf));
	if (retval != sizeof(txbuf)) {
		dev_err(&client->dev,
			"%s: set page failed: %d.", __func__, retval);
		return (retval < 0) ? retval : -EIO;
	}

	rmi_i2c->page = page;
	return 0;
}

static int rmi_i2c_write_block(struct rmi_transport_dev *xport, u16 addr,
			       const void *buf, size_t len)
{
	struct rmi_i2c_xport *rmi_i2c =
		container_of(xport, struct rmi_i2c_xport, xport);
	struct i2c_client *client = rmi_i2c->client;
	size_t tx_size = len + 1;
	int retval;

	mutex_lock(&rmi_i2c->page_mutex);

	if (!rmi_i2c->tx_buf || rmi_i2c->tx_buf_size < tx_size) {
		if (rmi_i2c->tx_buf)
			devm_kfree(&client->dev, rmi_i2c->tx_buf);
		rmi_i2c->tx_buf_size = tx_size + BUFFER_SIZE_INCREMENT;
		rmi_i2c->tx_buf = devm_kzalloc(&client->dev,
					       rmi_i2c->tx_buf_size,
					       GFP_KERNEL);
		if (!rmi_i2c->tx_buf) {
			rmi_i2c->tx_buf_size = 0;
			retval = -ENOMEM;
			goto exit;
		}
	}

	rmi_i2c->tx_buf[0] = addr & 0xff;
	memcpy(rmi_i2c->tx_buf + 1, buf, len);

	if (RMI_I2C_PAGE(addr) != rmi_i2c->page) {
		retval = rmi_set_page(rmi_i2c, RMI_I2C_PAGE(addr));
		if (retval)
			goto exit;
	}

	retval = i2c_master_send(client, rmi_i2c->tx_buf, tx_size);
	if (retval == tx_size)
		retval = 0;
	else if (retval >= 0)
		retval = -EIO;

exit:
	rmi_dbg(RMI_DEBUG_XPORT, &client->dev,

Annotation

Implementation Notes