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

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

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