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

[Jeff LaBundy <jeff@labundy.com>]

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.

> 
> -- 
> Dmitry

Kind regards,
Jeff LaBundy