[PATCH] leds: leds-lp50xx: allow LED 0 to be added to module bank

[PATCH] leds: leds-lp50xx: allow LED 0 to be added to module bank

[Christian Hitz]

From: Christian Hitz <christian.hitz@bbv.ch>

led_banks contains LED module number(s) that should be grouped into the
module bank. led_banks is 0-initialized.
By checking the led_banks entries for 0, un-set entries are detected.
But a 0-entry also indicates that LED module 0 should be grouped into the
module bank.

By only iterating over the available entries no check for unused entries
is required and LED module 0 can be added to bank.

Signed-off-by: Christian Hitz <christian.hitz@bbv.ch>
Cc: stable@vger.kernel.org
---
 drivers/leds/leds-lp50xx.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/drivers/leds/leds-lp50xx.c b/drivers/leds/leds-lp50xx.c
index 94f8ef6b482c..d50c7f3e8f99 100644
--- a/drivers/leds/leds-lp50xx.c
+++ b/drivers/leds/leds-lp50xx.c
@@ -341,17 +341,15 @@ static int lp50xx_brightness_set(struct led_classdev *cdev,
 	return ret;
 }
 
-static int lp50xx_set_banks(struct lp50xx *priv, u32 led_banks[])
+static int lp50xx_set_banks(struct lp50xx *priv, u32 led_banks[], int num_leds)
 {
 	u8 led_config_lo, led_config_hi;
 	u32 bank_enable_mask = 0;
 	int ret;
 	int i;
 
-	for (i = 0; i < priv->chip_info->max_modules; i++) {
-		if (led_banks[i])
-			bank_enable_mask |= (1 << led_banks[i]);
-	}
+	for (i = 0; i < num_leds; i++)
+		bank_enable_mask |= (1 << led_banks[i]);
 
 	led_config_lo = bank_enable_mask;
 	led_config_hi = bank_enable_mask >> 8;
@@ -405,7 +403,7 @@ static int lp50xx_probe_leds(struct fwnode_handle *child, struct lp50xx *priv,
 			return ret;
 		}
 
-		ret = lp50xx_set_banks(priv, led_banks);
+		ret = lp50xx_set_banks(priv, led_banks, num_leds);
 		if (ret) {
 			dev_err(priv->dev, "Cannot setup banked LEDs\n");
 			return ret;
-- 
2.51.0

Re: [PATCH] leds: leds-lp50xx: allow LED 0 to be added to module bank

[Jacek Anaszewski]

Hi Christian,

On 10/8/25 14:32, Christian Hitz wrote:
> From: Christian Hitz <christian.hitz@bbv.ch>
> 
> led_banks contains LED module number(s) that should be grouped into the
> module bank. led_banks is 0-initialized.
> By checking the led_banks entries for 0, un-set entries are detected.
> But a 0-entry also indicates that LED module 0 should be grouped into the
> module bank.
> 
> By only iterating over the available entries no check for unused entries
> is required and LED module 0 can be added to bank.
> 
> Signed-off-by: Christian Hitz <christian.hitz@bbv.ch>
> Cc: stable@vger.kernel.org
> ---
>   drivers/leds/leds-lp50xx.c | 10 ++++------
>   1 file changed, 4 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/leds/leds-lp50xx.c b/drivers/leds/leds-lp50xx.c
> index 94f8ef6b482c..d50c7f3e8f99 100644
> --- a/drivers/leds/leds-lp50xx.c
> +++ b/drivers/leds/leds-lp50xx.c
> @@ -341,17 +341,15 @@ static int lp50xx_brightness_set(struct led_classdev *cdev,
>   	return ret;
>   }
>   
> -static int lp50xx_set_banks(struct lp50xx *priv, u32 led_banks[])
> +static int lp50xx_set_banks(struct lp50xx *priv, u32 led_banks[], int num_leds)
>   {
>   	u8 led_config_lo, led_config_hi;
>   	u32 bank_enable_mask = 0;
>   	int ret;
>   	int i;
>   
> -	for (i = 0; i < priv->chip_info->max_modules; i++) {
> -		if (led_banks[i])
> -			bank_enable_mask |= (1 << led_banks[i]);
> -	}
> +	for (i = 0; i < num_leds; i++)
> +		bank_enable_mask |= (1 << led_banks[i]);

Probably the first idea was to have a bitmask indicating which bank
to enable, but it ended up in having array of bank ids in DT with no
related adjustment in the driver.

This patch deserves Fixes tag.

>   
>   	led_config_lo = bank_enable_mask;
>   	led_config_hi = bank_enable_mask >> 8;
> @@ -405,7 +403,7 @@ static int lp50xx_probe_leds(struct fwnode_handle *child, struct lp50xx *priv,
>   			return ret;
>   		}
>   
> -		ret = lp50xx_set_banks(priv, led_banks);
> +		ret = lp50xx_set_banks(priv, led_banks, num_leds);
>   		if (ret) {
>   			dev_err(priv->dev, "Cannot setup banked LEDs\n");
>   			return ret;

Reviewed-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>

-- 
Best regards,
Jacek Anaszewski

Re: [PATCH] leds: leds-lp50xx: allow LED 0 to be added to module bank

[Christian Hitz]

On Sat, 11 Oct 2025 14:16:16 +0200 Jacek Anaszewski <jacek.anaszewski@gmail.com> wrote:

> Hi Christian,
> 
> On 10/8/25 14:32, Christian Hitz wrote:
> > From: Christian Hitz <christian.hitz@bbv.ch>
> > 
> > led_banks contains LED module number(s) that should be grouped into the
> > module bank. led_banks is 0-initialized.
> > By checking the led_banks entries for 0, un-set entries are detected.
> > But a 0-entry also indicates that LED module 0 should be grouped into the
> > module bank.
> > 
> > By only iterating over the available entries no check for unused entries
> > is required and LED module 0 can be added to bank.
> > 
> > Signed-off-by: Christian Hitz <christian.hitz@bbv.ch>
> > Cc: stable@vger.kernel.org
> > ---
> >   drivers/leds/leds-lp50xx.c | 10 ++++------
> >   1 file changed, 4 insertions(+), 6 deletions(-)
> > 
> > diff --git a/drivers/leds/leds-lp50xx.c b/drivers/leds/leds-lp50xx.c
> > index 94f8ef6b482c..d50c7f3e8f99 100644
> > --- a/drivers/leds/leds-lp50xx.c
> > +++ b/drivers/leds/leds-lp50xx.c
> > @@ -341,17 +341,15 @@ static int lp50xx_brightness_set(struct led_classdev *cdev,
> >   	return ret;
> >   }
> >   
> > -static int lp50xx_set_banks(struct lp50xx *priv, u32 led_banks[])
> > +static int lp50xx_set_banks(struct lp50xx *priv, u32 led_banks[], int num_leds)
> >   {
> >   	u8 led_config_lo, led_config_hi;
> >   	u32 bank_enable_mask = 0;
> >   	int ret;
> >   	int i;
> >   
> > -	for (i = 0; i < priv->chip_info->max_modules; i++) {
> > -		if (led_banks[i])
> > -			bank_enable_mask |= (1 << led_banks[i]);
> > -	}
> > +	for (i = 0; i < num_leds; i++)
> > +		bank_enable_mask |= (1 << led_banks[i]);
> 
> Probably the first idea was to have a bitmask indicating which bank
> to enable, but it ended up in having array of bank ids in DT with no
> related adjustment in the driver.
> 
> This patch deserves Fixes tag.

This code has not changed since the inital introduction of this driver.

Fixes: 242b81170fb8 ("leds: lp50xx: Add the LP50XX family of the RGB LED driver")

> 
> >   
> >   	led_config_lo = bank_enable_mask;
> >   	led_config_hi = bank_enable_mask >> 8;
> > @@ -405,7 +403,7 @@ static int lp50xx_probe_leds(struct fwnode_handle *child, struct lp50xx *priv,
> >   			return ret;
> >   		}
> >   
> > -		ret = lp50xx_set_banks(priv, led_banks);
> > +		ret = lp50xx_set_banks(priv, led_banks, num_leds);
> >   		if (ret) {
> >   			dev_err(priv->dev, "Cannot setup banked LEDs\n");
> >   			return ret;
> 
> Reviewed-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>
> 
> -- 
> Best regards,
> Jacek Anaszewski

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Re: [PATCH] leds: leds-lp50xx: allow LED 0 to be added to module bank

[Jacek Anaszewski]

On 10/13/25 10:54, Christian Hitz wrote:
> On Sat, 11 Oct 2025 14:16:16 +0200 Jacek Anaszewski <jacek.anaszewski@gmail.com> wrote:
> 
>> Hi Christian,
>>
>> On 10/8/25 14:32, Christian Hitz wrote:
>>> From: Christian Hitz <christian.hitz@bbv.ch>
>>>
>>> led_banks contains LED module number(s) that should be grouped into the
>>> module bank. led_banks is 0-initialized.
>>> By checking the led_banks entries for 0, un-set entries are detected.
>>> But a 0-entry also indicates that LED module 0 should be grouped into the
>>> module bank.
>>>
>>> By only iterating over the available entries no check for unused entries
>>> is required and LED module 0 can be added to bank.
>>>
>>> Signed-off-by: Christian Hitz <christian.hitz@bbv.ch>
>>> Cc: stable@vger.kernel.org
>>> ---
>>>    drivers/leds/leds-lp50xx.c | 10 ++++------
>>>    1 file changed, 4 insertions(+), 6 deletions(-)
>>>
>>> diff --git a/drivers/leds/leds-lp50xx.c b/drivers/leds/leds-lp50xx.c
>>> index 94f8ef6b482c..d50c7f3e8f99 100644
>>> --- a/drivers/leds/leds-lp50xx.c
>>> +++ b/drivers/leds/leds-lp50xx.c
>>> @@ -341,17 +341,15 @@ static int lp50xx_brightness_set(struct led_classdev *cdev,
>>>    	return ret;
>>>    }
>>>    
>>> -static int lp50xx_set_banks(struct lp50xx *priv, u32 led_banks[])
>>> +static int lp50xx_set_banks(struct lp50xx *priv, u32 led_banks[], int num_leds)
>>>    {
>>>    	u8 led_config_lo, led_config_hi;
>>>    	u32 bank_enable_mask = 0;
>>>    	int ret;
>>>    	int i;
>>>    
>>> -	for (i = 0; i < priv->chip_info->max_modules; i++) {
>>> -		if (led_banks[i])
>>> -			bank_enable_mask |= (1 << led_banks[i]);
>>> -	}
>>> +	for (i = 0; i < num_leds; i++)
>>> +		bank_enable_mask |= (1 << led_banks[i]);
>>
>> Probably the first idea was to have a bitmask indicating which bank
>> to enable, but it ended up in having array of bank ids in DT with no
>> related adjustment in the driver.
>>
>> This patch deserves Fixes tag.
> 
> This code has not changed since the inital introduction of this driver.

Yeah, I had on mind design approach changes between subsequent
versions of the patch that was adding the driver.

> Fixes: 242b81170fb8 ("leds: lp50xx: Add the LP50XX family of the RGB LED driver")
-- 
Best regards,
Jacek Anaszewski

Re: (subset) [PATCH] leds: leds-lp50xx: allow LED 0 to be added to module bank

[Lee Jones]

On Wed, 08 Oct 2025 14:32:21 +0200, Christian Hitz wrote:
> led_banks contains LED module number(s) that should be grouped into the
> module bank. led_banks is 0-initialized.
> By checking the led_banks entries for 0, un-set entries are detected.
> But a 0-entry also indicates that LED module 0 should be grouped into the
> module bank.
> 
> By only iterating over the available entries no check for unused entries
> is required and LED module 0 can be added to bank.
> 
> [...]

Applied, thanks!

[1/1] leds: leds-lp50xx: allow LED 0 to be added to module bank
      commit: 26fe74d598c32e7bc6f150edfc4aa43e1bee55db

--
Lee Jones [李琼斯]