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

[ Upstream commit 934df23171e7c5b71d937104d4957891c39748ff ]

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>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/input/touchscreen/tsc2007.c b/drivers/input/touchscreen/tsc2007.c
index 5d0cd51..a4b7b4c 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,