[PATCH v3 4/8] drivers:input:tsc2007: check for presence and power down tsc2007 during probe

H. Nikolaus Schaller
2016-09-23T12:41:12Z

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>
---
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 559cbc6..3ddc31e 100644
--- a/drivers/input/touchscreen/tsc2007.c
+++ b/drivers/input/touchscreen/tsc2007.c
@@ -657,6 +657,15 @@ 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