Re: [PATCH] Input: elan_i2c - check if device is there before really probing
From: Guenter Roeck <linux@roeck-us.net>
Date: 2017-05-04 06:43:03
Also in:
lkml
On 05/03/2017 11:29 PM, Dmitry Torokhov wrote:
quoted hunk ↗ jump to hunk
Before trying to properly initialize the touchpad and generate bunch of errors, let's first see it there is anything at the given address. If we get error, fail silently with -ENXIO. Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> --- drivers/input/mouse/elan_i2c_core.c | 9 +++++++++ 1 file changed, 9 insertions(+)diff --git a/drivers/input/mouse/elan_i2c_core.c b/drivers/input/mouse/elan_i2c_core.c index 5d3b53dd2fa2..0479730e7c5c 100644 --- a/drivers/input/mouse/elan_i2c_core.c +++ b/drivers/input/mouse/elan_i2c_core.c@@ -1040,6 +1040,7 @@ static int elan_probe(struct i2c_client *client, const struct elan_transport_ops *transport_ops; struct device *dev = &client->dev; struct elan_tp_data *data; + union i2c_smbus_data dummy; unsigned long irqflags; int error;@@ -1091,6 +1092,14 @@ static int elan_probe(struct i2c_client *client, return error; } + /* Make sure there is something at this address */ + error = i2c_smbus_xfer(client->adapter, client->addr, 0, + I2C_SMBUS_READ, 0, I2C_SMBUS_BYTE, &dummy);
Can't you just call i2c_smbus_read_byte_data(client, 0); and check if it returns an error ? Thanks, Guenter
+ if (error) {
+ dev_dbg(&client->dev, "nothing at this address: %d\n", error);
+ return -ENXIO;
+ }
+
/* Initialize the touchpad. */
error = elan_initialize(data);
if (error)