Hi,
On 24-03-2023 09:06 pm, Christophe JAILLET wrote:
Le 24/03/2023 à 11:54, Naresh Solanki a écrit :
Hi,
On 24-03-2023 01:48 am, Christophe JAILLET wrote:
Le 23/03/2023 à 20:45, Naresh Solanki a écrit :
From: Patrick Rudolph <patrick.rudolph@xxxxxxxxxxxxx>
max597x is hot swap controller with indicator LED support.
This driver uses DT property to configure led during boot time &
also provide the LED control in sysfs.
[...]
+static int max597x_led_probe(struct platform_device *pdev)
+{
+ struct device_node *np = dev_of_node(pdev->dev.parent);
+ struct regmap *regmap = dev_get_regmap(pdev->dev.parent, NULL);
+ struct device_node *led_node;
+ struct device_node *child;
+ int ret = 0;
+
+ if (!regmap)
+ return -EPROBE_DEFER;
+
+ led_node = of_get_child_by_name(np, "leds");
+ if (!led_node)
+ return -ENODEV;
+
+ for_each_available_child_of_node(led_node, child) {
+ u32 reg;
+
+ if (of_property_read_u32(child, "reg", ®))
+ continue;
+
+ if (reg >= MAX597X_NUM_LEDS) {
+ dev_err(&pdev->dev, "invalid LED (%u >= %d)\n", reg,
+ MAX597X_NUM_LEDS);
+ continue;
+ }
+
+ ret = max597x_setup_led(&pdev->dev, regmap, child, reg);
+ if (ret < 0)
+ of_node_put(child);
This of_node_put() looks odd to me.
Not sure if I get this right but if led setup fails of_node_put should
be called.
My understanding is that this of_node_put() is there in case of error,
to release what would otherwise never be released by
for_each_available_child_of_node() if we exit early from the loop.
If the purpose is to release a reference taken in max597x_setup_led() in
case of error:
- this should be done IMHO within max597x_setup_led() directly
- there should be a of_node_get() somewhere in max597x_setup_led()
(after:
if (of_property_read_string(nc, "label", &led->led.name))
led->led.name = nc->name;
+ error handling path, *or*
just before the final return ret; when we know that everything is
fine,
if I understand correctly the code)
Is the reference taken elsewhere?
Did I miss something obvious?
One of the reference is "drivers/leds/leds-sc27xx-bltc.c" line 311
Please do let me know if I have to do anything about it.
"return ret;" or "break;" missing ?
Didn't add a break so that it can continue initializing remaining led
if any.
Ok. Don't know the code enough to see if correct or not, but based on my
comment above, I think that something is missing in max597x_setup_led()
and that errors should be silently ignored here.
In my implementation, I have chosen to continue with the next LED if an
error occurs, rather than aborting the 'for loop' with an error. I have
seen other implementations also done in a similar way.
Do you have any further inputs or suggestions on this approach.
CJ
+ }
+
+ return ret;
+}
+
[...]
Regards,
Naresh
