return quirks;
}
+static int i2c_hid_probe_address(struct i2c_hid *ihid)
+{
+ int ret;
+
+ /*
+ * Some STM-based devices need 400µs after a rising clock edge to wake
+ * from deep sleep, in which case the first read will fail. Try after a
+ * short sleep to see if the device came alive on the bus. Certain
+ * Weida Tech devices also need this.
+ */
+ ret = i2c_smbus_read_byte(ihid->client);
+ if (ret < 0) {
+ usleep_range(400, 500);
+ ret = i2c_smbus_read_byte(ihid->client);
+ }
+ return ret < 0 ? ret : 0;
+}
+
static int i2c_hid_xfer(struct i2c_hid *ihid,
u8 *send_buf, int send_len, u8 *recv_buf, int recv_len)
{
struct hid_device *hid = ihid->hid;
int ret;
- /* Make sure there is something at this address */
- ret = i2c_smbus_read_byte(client);
+ ret = i2c_hid_probe_address(ihid);
if (ret < 0) {
i2c_hid_dbg(ihid, "nothing at this address: %d\n", ret);
return -ENXIO;