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Commit 5ddfb12e authored by Ellen Wang's avatar Ellen Wang Committed by Jiri Kosina
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HID: cp2112: support large i2c transfers 



cp2112_i2c_xfer() only reads up to 61 bytes, returning EIO on longers reads.
The fix is to wrap a loop around cp2112_read() to pick up all the returned
data.

Signed-off-by: default avatarEllen Wang <ellen@cumulusnetworks.com>
Signed-off-by: default avatarJiri Kosina <jkosina@suse.com>
parent 6debce6f

drivers/hid/hid-cp2112.c

+24 −7
Original line number Diff line number Diff line
@@ -511,14 +511,31 @@ static int cp2112_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, 
	if (!(msgs->flags & I2C_M_RD))

		goto finish;



	ret = cp2112_read(dev, msgs->buf, msgs->len);

	for (count = 0; count < msgs->len;) {

		ret = cp2112_read(dev, msgs->buf + count, msgs->len - count);

		if (ret < 0)

			goto power_normal;

	if (ret != msgs->len) {

		hid_warn(hdev, "short read: %d < %d\n", ret, msgs->len);

		if (ret == 0) {

			hid_err(hdev, "read returned 0\n");

			ret = -EIO;

			goto power_normal;

		}

		count += ret;

		if (count > msgs->len) {

			/*

			 * The hardware returned too much data.

			 * This is mostly harmless because cp2112_read()

			 * has a limit check so didn't overrun our

			 * buffer.  Nevertheless, we return an error

			 * because something is seriously wrong and

			 * it shouldn't go unnoticed.

			 */

			hid_err(hdev, "long read: %d > %zd\n",

				ret, msgs->len - count + ret);

			ret = -EIO;

			goto power_normal;

		}

	}



finish:

	/* return the number of transferred messages */