1. check if chip is really present and don't succeed if it isn't. 2. if it succeeds, power down the chip until accessed Signed-off-by: H. Nikolaus Schaller <hns@xxxxxxxxxxxxx> --- drivers/input/touchscreen/tsc2007.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/drivers/input/touchscreen/tsc2007.c b/drivers/input/touchscreen/tsc2007.c index e9d5086..c314331 100644 --- a/drivers/input/touchscreen/tsc2007.c +++ b/drivers/input/touchscreen/tsc2007.c @@ -538,6 +538,15 @@ static int tsc2007_probe(struct i2c_client *client, tsc2007_stop(ts); + /* power down the chip (TSC2007_SETUP does not ACK on I2C) */ + err = tsc2007_xfer(ts, PWRDOWN); + if (err < 0) { + dev_err(&client->dev, + "Failed to setup chip: %d\n", err); + iio_device_unregister(indio_dev); + return err; /* usually, chip does not respond */ + } + err = input_register_device(input_dev); if (err) { dev_err(&client->dev, -- 2.7.3 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html