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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: Ellen Wang <ellen@cumulusnetworks.com>
Signed-off-by: Jiri Kosina <jkosina@suse.com>
hifive-unleashed-5.1
Ellen Wang 2015-07-08 11:17:39 -07:00 committed by Jiri Kosina
parent 6debce6f4e
commit 5ddfb12e90
1 changed files with 24 additions and 7 deletions
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31
drivers/hid/hid-cp2112.c
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@ -511,13 +511,30 @@ 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);
if (ret < 0)
goto power_normal;
if (ret != msgs->len) {
hid_warn(hdev, "short read: %d < %d\n", ret, msgs->len);
ret = -EIO;
goto power_normal;
for (count = 0; count < msgs->len;) {
ret = cp2112_read(dev, msgs->buf + count, msgs->len - count);
if (ret < 0)
goto power_normal;
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: