Re: [PATCH 02/11] Input: iqs7222 - report malformed properties

Dmitry Torokhov
2022-09-09T04:42:59Z

On Thu, Sep 08, 2022 at 09:08:09PM -0500, Jeff LaBundy wrote:
> Hi Dmitry,
>
> On Thu, Sep 08, 2022 at 02:21:13PM -0700, Dmitry Torokhov wrote:
> > On Thu, Sep 08, 2022 at 08:15:39AM -0500, Jeff LaBundy wrote:
> > > Nonzero return values of several calls to fwnode_property_read_u32()
> > > are silenty ignored, leaving no way to know that the properties were
> > > not applied in the event of an error.
> > >
> > > To solve this problem, follow the design pattern used throughout the
> > > rest of the driver by first checking if the property is present, and
> > > then evaluating the return value of fwnode_property_read_u32().
> > >
> > > Fixes: e505edaedcb9 ("Input: add support for Azoteq IQS7222A/B/C")
> > > Signed-off-by: Jeff LaBundy <jeff@labundy.com>
> > > ---
> > > drivers/input/misc/iqs7222.c | 65 ++++++++++++++++++++++++++++++------
> > > 1 file changed, 55 insertions(+), 10 deletions(-)
> > >
> > > diff --git a/drivers/input/misc/iqs7222.c b/drivers/input/misc/iqs7222.c
> > > index 04c1050d845c..fdade24caa8a 100644
> > > --- a/drivers/input/misc/iqs7222.c
> > > +++ b/drivers/input/misc/iqs7222.c
> > > @@ -1819,8 +1819,17 @@ static int iqs7222_parse_chan(struct iqs7222_private *iqs7222, int chan_index)
> > > chan_setup[0] |= IQS7222_CHAN_SETUP_0_REF_MODE_FOLLOW;
> > > chan_setup[4] = val * 42 + 1048;
> > >
> > > - if (!fwnode_property_read_u32(chan_node, "azoteq,ref-weight",
> > > - &val)) {
> > > + if (fwnode_property_present(chan_node, "azoteq,ref-weight")) {
> > > + error = fwnode_property_read_u32(chan_node,
> > > + "azoteq,ref-weight",
> > > + &val);
> >
> > fwnode_property_read_u32() returns EINVAL if property is missing, so
> > maybe have:
> >
> > error = fwnode_property_read_u32(chan_node,
> > "azoteq,ref-weight", &val);
> > if (!error) {
> > ...
> > } else {
> > if (error != -EINVAL) {
> > dev_err(&client->dev,
> > "Failed to read %s reference weight: %d\n",
> > fwnode_get_name(chan_node), error);
> > goto put_chan_node;
> > }
> > }
> >
> > to avoid double calls into property handling code?
>
> That's a better idea; I can fold this into the helper functions proposed
> for the previous patch too.

We might be talking about different helpers. I had in mind:

static int __iqs7222_parse_cycle(...)
{
...
}

static int iqs7222_parse_cycle(...)
{
...
int retval = 0;

error = iqs7222_parse_props(iqs7222, &cycle_node, cycle_index,
IQS7222_REG_GRP_CYCLE,
IQS7222_REG_KEY_NONE);
if (error)
return error;

if (cycle_node) {
retval = __iqs7222_parse_cycle(...);
fwnode_put(cycle_node);
}

return retval;
}

so that we drop the node from one place.

Thanks.

--
Dmitry