diff options
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/w1/masters/ds2490.c | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/drivers/w1/masters/ds2490.c b/drivers/w1/masters/ds2490.c index 9a7fd71e146..0f356939b34 100644 --- a/drivers/w1/masters/ds2490.c +++ b/drivers/w1/masters/ds2490.c @@ -316,6 +316,15 @@ static int ds_recv_data(struct ds_device *dev, unsigned char *buf, int size) int count, err; struct ds_status st; + /* Careful on size. If size is less than what is available in + * the input buffer, the device fails the bulk transfer and + * clears the input buffer. It could read the maximum size of + * the data buffer, but then do you return the first, last, or + * some set of the middle size bytes? As long as the rest of + * the code is correct there will be size bytes waiting. A + * call to ds_wait_status will wait until the device is idle + * and any data to be received would have been available. + */ count = 0; err = usb_bulk_msg(dev->udev, usb_rcvbulkpipe(dev->udev, dev->ep[EP_DATA_IN]), buf, size, &count, 1000); @@ -824,6 +833,18 @@ static int ds_w1_init(struct ds_device *dev) { memset(&dev->master, 0, sizeof(struct w1_bus_master)); + /* Reset the device as it can be in a bad state. + * This is necessary because a block write will wait for data + * to be placed in the output buffer and block any later + * commands which will keep accumulating and the device will + * not be idle. Another case is removing the ds2490 module + * while a bus search is in progress, somehow a few commands + * get through, but the input transfers fail leaving data in + * the input buffer. This will cause the next read to fail + * see the note in ds_recv_data. + */ + ds_send_control_cmd(dev, CTL_RESET_DEVICE, 0); + dev->master.data = dev; dev->master.touch_bit = &ds9490r_touch_bit; /* read_bit and write_bit in w1_bus_master are expected to set and |