On Sat, Dec 14, 2024 at 12:02:56AM +0100, Uwe Kleine-König wrote: > Hello Frank, > > On Fri, Dec 13, 2024 at 05:23:09PM -0500, Frank Li wrote: > > From: Luwei Zhou <b45643@xxxxxxxxxxxxx> > > > > Prevent continuous polling error logs by adding a chip ID check in the > > probe function. This ensures the driver only proceeds when the mma8450 is > > present, avoiding issues in scenarios like missing add-on cards. > > > > Signed-off-by: Luwei Zhou <b45643@xxxxxxxxxxxxx> > > Signed-off-by: Fugang Duan <B38611@xxxxxxxxxxxxx> > > Signed-off-by: Vipul Kumar <vipul_kumar@xxxxxxxxxx> > > Signed-off-by: Dong Aisheng <aisheng.dong@xxxxxxx> > > Signed-off-by: Frank Li <Frank.Li@xxxxxxx> > > --- > > drivers/input/misc/mma8450.c | 16 +++++++++++++++- > > 1 file changed, 15 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/input/misc/mma8450.c b/drivers/input/misc/mma8450.c > > index 08412239b8e69..da941748ed29b 100644 > > --- a/drivers/input/misc/mma8450.c > > +++ b/drivers/input/misc/mma8450.c > > @@ -38,6 +38,8 @@ > > > > #define MMA8450_CTRL_REG1 0x38 > > #define MMA8450_CTRL_REG2 0x39 > > +#define MMA8450_ID 0xc6 > > +#define MMA8450_WHO_AM_I 0x0f > > > > static int mma8450_read(struct i2c_client *c, unsigned int off) > > { > > @@ -148,8 +150,20 @@ static void mma8450_close(struct input_dev *input) > > */ > > static int mma8450_probe(struct i2c_client *c) > > { > > + struct i2c_adapter *adapter = to_i2c_adapter(c->dev.parent); > > + struct i2c_adapter *adapter = c->adapter; > > > struct input_dev *input; > > - int err; > > + int err, client_id; > > + > > + err = i2c_check_functionality(adapter, > > + I2C_FUNC_SMBUS_BYTE | I2C_FUNC_SMBUS_BYTE_DATA); > > + if (!err) > > + return err; > > How unusual. I would have expected no ! here. yes, it should be better if (!i2c_check_functionality()) .... i2c_check_functionality() return 1 if adapter supports everything we need. Frank > > > + client_id = i2c_smbus_read_byte_data(c, MMA8450_WHO_AM_I); > > + if (client_id != MMA8450_ID) > > + return dev_err_probe(&c->dev, -EINVAL, > > + "read chip ID 0x%x is not equal to 0x%x!\n", > > + client_id, MMA8450_ID); > > Given that here you emit an error message, maybe add an error message > above, too? > > > input = devm_input_allocate_device(&c->dev); > > if (!input) > > Best regards > Uwe