On Mon, Dec 16, 2024 at 11:30:15AM -0500, Frank Li wrote:
> 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.
Yes, it would be much better, otherwise in the case when an adapter does
not support the required functionality your code returns 0 which signals
successful probing.
Thanks.
--
Dmitry
