Input: tsc2007 - check for presence and power down tsc2007 during probe

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@goldelico.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

diff --git a/drivers/input/touchscreen/tsc2007.c b/drivers/input/touchscreen/tsc2007.c
index 5d0cd51c6f41d126beef0e6e4bc7580288129cf6..a4b7b4c3d27b29f0aae7286415ec6e3e9b5e44a7 100644 (file)
--- a/drivers/input/touchscreen/tsc2007.c
+++ b/drivers/input/touchscreen/tsc2007.c
@@ -455,6 +455,14 @@ 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);
+               return err;     /* usually, chip does not respond */
+       }
+
        err = input_register_device(input_dev);
        if (err) {
                dev_err(&client->dev,