linux-kernel - Re: [PATCH v4 04/11] leds: aw200xx: calculate dts property display

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Message-ID: <20231127085755.GE1470173@google.com>
Date:   Mon, 27 Nov 2023 08:57:55 +0000
From:   Lee Jones <lee@...nel.org>
To:     Dmitry Rokosov <ddrokosov@...utedevices.com>
Cc:     pavel@....cz, robh+dt@...nel.org,
        krzysztof.kozlowski+dt@...aro.org, conor+dt@...nel.org,
        andy.shevchenko@...il.com, kernel@...rdevices.ru,
        rockosov@...il.com, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-leds@...r.kernel.org,
        George Stark <gnstark@...utedevices.com>
Subject: Re: [PATCH v4 04/11] leds: aw200xx: calculate dts property
 display_rows in the driver

On Fri, 24 Nov 2023, Dmitry Rokosov wrote:

> On Thu, Nov 23, 2023 at 04:32:52PM +0000, Lee Jones wrote:
> > On Tue, 21 Nov 2023, Dmitry Rokosov wrote:
> > 
> > > From: George Stark <gnstark@...utedevices.com>
> > > 
> > > Get rid of device tree property "awinic,display-rows". The property
> > > value actually means number of current switches and depends on how leds
> > 
> > Nit: LEDs
> > 
> > > are connected to the device. It should be calculated manually by max
> > > used led number. In the same way it is computed automatically now.
> > 
> > As above - I won't mention this again.
> > 
> > > Max used led is taken from led definition subnodes.
> > > 
> > > Signed-off-by: George Stark <gnstark@...utedevices.com>
> > > Signed-off-by: Dmitry Rokosov <ddrokosov@...utedevices.com>
> > > ---
> > >  drivers/leds/leds-aw200xx.c | 39 +++++++++++++++++++++++++------------
> > >  1 file changed, 27 insertions(+), 12 deletions(-)
> > > 
> > > diff --git a/drivers/leds/leds-aw200xx.c b/drivers/leds/leds-aw200xx.c
> > > index 7762b3a132ac..4bce5e7381c0 100644
> > > --- a/drivers/leds/leds-aw200xx.c
> > > +++ b/drivers/leds/leds-aw200xx.c
> > > @@ -379,6 +379,30 @@ static void aw200xx_disable(const struct aw200xx *const chip)
> > >  	return gpiod_set_value_cansleep(chip->hwen, 0);
> > >  }
> > >  
> > > +static bool aw200xx_probe_get_display_rows(struct device *dev, struct aw200xx *chip)
> > > +{
> > > +	struct fwnode_handle *child;
> > > +	u32 max_source = 0;
> > > +
> > > +	device_for_each_child_node(dev, child) {
> > > +		u32 source;
> > > +		int ret;
> > > +
> > > +		ret = fwnode_property_read_u32(child, "reg", &source);
> > > +		if (ret || source >= chip->cdef->channels)
> > 
> > Shouldn't the second clause fail instantly?
> > 
> 
> We already have such logic in the aw200xx_probe_fw() function, which
> skips the LED node with the wrong reg value too. Furthermore, we have
> strict reg constraints in the dt-bindings parts (in the current patch
> series), so we assume that the DT developer will not create an LED with
> the wrong reg value.

Why is it being checked again then?

-- 
Lee Jones [李琼斯]