linux-kernel - Re: [PATCH v4 3/6] auxdisplay: Add TM16xx 7-segment LED matrix display controllers driver

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Message-ID: <aLU3ZhOaBlE-e4gO@smile.fi.intel.com>
Date: Mon, 1 Sep 2025 09:04:22 +0300
From: Andy Shevchenko <andriy.shevchenko@...el.com>
To: Jean-François Lessard <jefflessard3@...il.com>
Cc: Andy Shevchenko <andy@...nel.org>,
	Geert Uytterhoeven <geert@...ux-m68k.org>,
	Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>, linux-kernel@...r.kernel.org,
	linux-leds@...r.kernel.org, devicetree@...r.kernel.org,
	Paolo Sabatino <paolo.sabatino@...il.com>,
	Christian Hewitt <christianshewitt@...il.com>,
	Boris Gjenero <boris.gjenero@...il.com>,
	Martin Blumenstingl <martin.blumenstingl@...glemail.com>
Subject: Re: [PATCH v4 3/6] auxdisplay: Add TM16xx 7-segment LED matrix
 display controllers driver

On Wed, Aug 27, 2025 at 02:37:47PM -0400, Jean-François Lessard wrote:
> Le 25 août 2025 13 h 48 min 45 s HAE, "Jean-François Lessard" <jefflessard3@...il.com> a écrit :
> >Le 25 août 2025 11 h 14 min 21 s HAE, Andy Shevchenko <andriy.shevchenko@...el.com> a écrit :
> >>On Sun, Aug 24, 2025 at 11:32:29PM -0400, Jean-François Lessard wrote:

...

> >>> +		fwnode_for_each_child_node(digits_node, child)
> >>> +			display->num_digits++;
> >>
> >>Don't we have a _count API for this?
> >>
> >
> >I'll use device_get_child_node_count() instead of manual counting loops.
> >
> >>> +		dev_dbg(dev, "Number of digits: %u\n", display->num_digits);
> >>> +
> >>> +		if (display->num_digits) {
> >>> +			display->digits = devm_kcalloc(dev, display->num_digits,
> >>> +						       sizeof(*display->digits),
> >>> +						       GFP_KERNEL);
> >>> +			if (!display->digits) {
> >>
> >>> +				fwnode_handle_put(digits_node);
> >>
> >>Use RAII instead, we have defined __free() method for this.
> >>
> >>> +				return -ENOMEM;
> >>> +			}
> >>> +
> >>> +			i = 0;
> >>> +			fwnode_for_each_child_node(digits_node, child) {
> >>
> >>Ditto. Use _scoped variant.
> >
> >Well received.
> 
> After further investigation, _scoped variant exists for
> device_for_each_child_node_scoped() but not for fwnode_for_each_child_node().
> 
> I suggest to include an additional patch in next submission to add to
> include/linux/property.h:
> 
> #define fwnode_for_each_child_node_scoped(fwnode, child)		\
> 	for (struct fwnode_handle *child __free(fwnode_handle) =	\
> 		fwnode_get_next_child_node(fwnode, NULL);		\
> 	     child; child = fwnode_get_next_child_node(fwnode, child))
> 
> #define fwnode_for_each_named_child_node_scoped(fwnode, child, name)	\
> 	fwnode_for_each_child_node_scoped(fwnode, child)		\
> 		for_each_if(fwnode_name_eq(child, name))
> 
> #define fwnode_for_each_available_child_node_scoped(fwnode, child)	\
> 	for (struct fwnode_handle *child __free(fwnode_handle) =	\
> 		fwnode_get_next_available_child_node(fwnode, NULL);	\
> 	     child; child = fwnode_get_next_available_child_node(fwnode, child))

LGTM!

-- 
With Best Regards,
Andy Shevchenko