Currently, when the LED is configured as a RGB LED or a multi-color
LED device, the same pattern is programmed for all LED channels
regardless of the sub-led intensities when triggered by HW pattern.
It results that the LED device is always working in a white-balanced
mode regardless of the intensity settings.

To fix this, scale the pattern data according to the sub-led intensity
and program the HW pattern separately for each LPG channel.

Fixes: 24e2d05d1b68 ("leds: Add driver for Qualcomm LPG")
Fixes: 6ab1f766a80a ("leds: rgb: leds-qcom-lpg: Add support for PPG through single SDAM")
Fixes: 5e9ff626861a ("leds: rgb: leds-qcom-lpg: Include support for PPG with dedicated LUT SDAM")
Assisted-by: Claude:claude-4-6-sonnet
Signed-off-by: Fenglin Wu <fenglin.wu@oss.qualcomm.com>
---
 drivers/leds/rgb/leds-qcom-lpg.c | 174 +++++++++++++++++++++++++++++++--------
 1 file changed, 141 insertions(+), 33 deletions(-)

diff --git a/drivers/leds/rgb/leds-qcom-lpg.c b/drivers/leds/rgb/leds-qcom-lpg.c
index d7d6518de30f..ca84da563e09 100644
--- a/drivers/leds/rgb/leds-qcom-lpg.c
+++ b/drivers/leds/rgb/leds-qcom-lpg.c
@@ -148,6 +148,24 @@ struct lpg_channel {
 	unsigned int pattern_hi_idx;
 };
 
+/**
+ * struct lpg_pattern - The LPG pattern normalized from the LED pattern
+ * @data:       The pattern data array (caller must kfree)
+ * @len:	number of entries to write to the LUT
+ * @delta_t:    common step duration in ms
+ * @lo_pause:   low-pause duration in ms
+ * @hi_pause:   high-pause duration in ms
+ * @ping_pong:  true if the pattern support reverse
+ */
+struct lpg_pattern {
+	struct led_pattern *data;
+	unsigned int len;
+	unsigned int delta_t;
+	unsigned int lo_pause;
+	unsigned int hi_pause;
+	bool ping_pong;
+};
+
 /**
  * struct lpg_led - logical LED object
  * @lpg:		lpg context reference
@@ -959,23 +977,23 @@ static int lpg_blink_mc_set(struct led_classdev *cdev,
 	return ret;
 }
 
-static int lpg_pattern_set(struct lpg_led *led, struct led_pattern *led_pattern,
-			   u32 len, int repeat)
+/**
+ * lpg_prepare_pattern() - validate and normalize a leds-trigger-pattern payload
+ *
+ * Collapses the paired-entry format required by the trigger into a compact
+ * array, detects palindrome ping-pong, and extracts timing parameters.
+ * On success the caller owns prep->data and must kfree() it.
+ */
+static int lpg_prepare_pattern(struct lpg *lpg, struct led_pattern *led_pattern,
+				u32 len, int repeat, struct lpg_pattern *prep)
 {
-	struct lpg_channel *chan;
-	struct lpg *lpg = led->lpg;
 	struct led_pattern *pattern;
 	unsigned int brightness_a;
 	unsigned int brightness_b;
-	unsigned int hi_pause = 0;
-	unsigned int lo_pause = 0;
 	unsigned int actual_len;
 	unsigned int delta_t;
-	unsigned int lo_idx;
-	unsigned int hi_idx;
 	unsigned int i;
 	bool ping_pong = true;
-	int ret = -EINVAL;
 
 	/* Hardware only support oneshot or indefinite loops */
 	if (repeat != -1 && repeat != 1)
@@ -1001,9 +1019,9 @@ static int lpg_pattern_set(struct lpg_led *led, struct led_pattern *led_pattern,
 
 	for (i = 0; i < len; i += 2) {
 		if (led_pattern[i].brightness != led_pattern[i + 1].brightness)
-			goto out_free_pattern;
+			goto out_free;
 		if (led_pattern[i + 1].delta_t != 0)
-			goto out_free_pattern;
+			goto out_free;
 
 		pattern[i / 2].brightness = led_pattern[i].brightness;
 		pattern[i / 2].delta_t = led_pattern[i].delta_t;
@@ -1016,7 +1034,7 @@ static int lpg_pattern_set(struct lpg_led *led, struct led_pattern *led_pattern,
 	 * through the entire LUT, so prohibit this.
 	 */
 	if (len < 2)
-		goto out_free_pattern;
+		goto out_free;
 
 	/*
 	 * The LPG plays patterns with at a fixed pace, a "low pause" can be
@@ -1073,13 +1091,13 @@ static int lpg_pattern_set(struct lpg_led *led, struct led_pattern *led_pattern,
 			 * specify hi pause. Reject other variations.
 			 */
 			if (i != actual_len - 1)
-				goto out_free_pattern;
+				goto out_free;
 		}
 	}
 
 	/* LPG_RAMP_DURATION_REG is a 9bit */
 	if (delta_t >= BIT(9))
-		goto out_free_pattern;
+		goto out_free;
 
 	/*
 	 * Find "low pause" and "high pause" in the pattern in the LUT case.
@@ -1087,20 +1105,48 @@ static int lpg_pattern_set(struct lpg_led *led, struct led_pattern *led_pattern,
 	 * duration of all steps.
 	 */
 	if (lpg->lut_base || lpg->lut_sdam) {
-		lo_pause = pattern[0].delta_t;
-		hi_pause = pattern[actual_len - 1].delta_t;
+		prep->lo_pause = pattern[0].delta_t;
+		prep->hi_pause = pattern[actual_len - 1].delta_t;
 	} else {
 		if (delta_t != pattern[0].delta_t || delta_t != pattern[actual_len - 1].delta_t)
-			goto out_free_pattern;
+			goto out_free;
+		prep->lo_pause = 0;
+		prep->hi_pause = 0;
 	}
 
+	prep->data = pattern;
+	prep->len = actual_len;
+	prep->delta_t = delta_t;
+	prep->ping_pong = ping_pong;
+
+	return 0;
+
+out_free:
+	kfree(pattern);
+	return -EINVAL;
+}
+
+static int lpg_pattern_set(struct lpg_led *led, struct led_pattern *led_pattern,
+			   u32 len, int repeat)
+{
+	struct lpg_channel *chan;
+	struct lpg *lpg = led->lpg;
+	struct lpg_pattern pattern;
+	unsigned int lo_idx;
+	unsigned int hi_idx;
+	unsigned int i;
+	int ret;
+
+	ret = lpg_prepare_pattern(lpg, led_pattern, len, repeat, &pattern);
+	if (ret < 0)
+		return ret;
 
 	mutex_lock(&lpg->lock);
 
 	if (lpg->lut_base)
-		ret = lpg_lut_store(lpg, pattern, actual_len, &lo_idx, &hi_idx);
+		ret = lpg_lut_store(lpg, pattern.data, pattern.len, &lo_idx, &hi_idx);
 	else
-		ret = lpg_lut_store_sdam(lpg, pattern, actual_len, &lo_idx, &hi_idx);
+		ret = lpg_lut_store_sdam(lpg, pattern.data, pattern.len, &lo_idx, &hi_idx);
 
 	if (ret < 0)
 		goto out_unlock;
@@ -1108,12 +1154,12 @@ static int lpg_pattern_set(struct lpg_led *led, struct led_pattern *led_pattern,
 	for (i = 0; i < led->num_channels; i++) {
 		chan = led->channels[i];
 
-		chan->ramp_tick_ms = delta_t;
-		chan->ramp_ping_pong = ping_pong;
+		chan->ramp_tick_ms = pattern.delta_t;
+		chan->ramp_ping_pong = pattern.ping_pong;
 		chan->ramp_oneshot = repeat != -1;
 
-		chan->ramp_lo_pause_ms = lo_pause;
-		chan->ramp_hi_pause_ms = hi_pause;
+		chan->ramp_lo_pause_ms = pattern.lo_pause;
+		chan->ramp_hi_pause_ms = pattern.hi_pause;
 
 		chan->pattern_lo_idx = lo_idx;
 		chan->pattern_hi_idx = hi_idx;
@@ -1121,8 +1167,7 @@ static int lpg_pattern_set(struct lpg_led *led, struct led_pattern *led_pattern,
 
 out_unlock:
 	mutex_unlock(&lpg->lock);
-out_free_pattern:
-	kfree(pattern);
+	kfree(pattern.data);
 
 	return ret;
 }
@@ -1144,23 +1189,88 @@ static int lpg_pattern_single_set(struct led_classdev *cdev,
 }
 
 static int lpg_pattern_mc_set(struct led_classdev *cdev,
-			      struct led_pattern *pattern, u32 len,
+			      struct led_pattern *led_pattern, u32 len,
 			      int repeat)
 {
 	struct led_classdev_mc *mc = lcdev_to_mccdev(cdev);
 	struct lpg_led *led = container_of(mc, struct lpg_led, mcdev);
+	struct lpg *lpg = led->lpg;
+	struct lpg_channel *chan;
+	struct lpg_pattern pattern;
+	struct led_pattern *scaled;
 	unsigned int triled_mask = 0;
-	int ret, i;
+	unsigned int lo_idx;
+	unsigned int hi_idx;
+	unsigned int scale;
+	unsigned int i, j;
+	int ret;
+
+	ret = lpg_prepare_pattern(lpg, led_pattern, len, repeat, &pattern);
+	if (ret < 0)
+		return ret;
+
+	/* Allocate buffer for the per-channel scaled pattern copy */
+	scaled = kmalloc_array(pattern.len, sizeof(*scaled), GFP_KERNEL);
+	if (!scaled) {
+		ret = -ENOMEM;
+		goto out_free_prep;
+	}
 
 	for (i = 0; i < led->num_channels; i++)
 		triled_mask |= led->channels[i]->triled_mask;
-	triled_set(led->lpg, triled_mask, 0);
+	triled_set(lpg, triled_mask, 0);
+
+	led_mc_calc_color_components(mc, LED_FULL);
+
+	/*
+	 * Each channel gets its own LUT block scaled by subled_info[i].brightness
+	 * so the pattern respects the configured colour balance.
+	 */
+	mutex_lock(&lpg->lock);
+	for (i = 0; i < led->num_channels; i++) {
+		chan = led->channels[i];
+		scale = mc->subled_info[i].brightness;
+
+		for (j = 0; j < pattern.len; j++) {
+			scaled[j].brightness = DIV_ROUND_CLOSEST(
+				(u32)pattern.data[j].brightness * scale, LED_FULL);
+			scaled[j].delta_t = pattern.data[j].delta_t;
+		}
+
+		if (lpg->lut_base)
+			ret = lpg_lut_store(lpg, scaled, pattern.len, &lo_idx, &hi_idx);
+		else
+			ret = lpg_lut_store_sdam(lpg, scaled, pattern.len, &lo_idx, &hi_idx);
+
+		if (ret < 0) {
+			/* Free LUT slots already allocated for previous channels */
+			while (i-- > 0) {
+				chan = led->channels[i];
+				lpg_lut_free(lpg, chan->pattern_lo_idx, chan->pattern_hi_idx);
+				chan->pattern_lo_idx = 0;
+				chan->pattern_hi_idx = 0;
+			}
+			goto out_unlock;
+		}
+
+		chan->ramp_tick_ms = pattern.delta_t;
+		chan->ramp_ping_pong = pattern.ping_pong;
+		chan->ramp_oneshot = repeat != -1;
+		chan->ramp_lo_pause_ms = pattern.lo_pause;
+		chan->ramp_hi_pause_ms = pattern.hi_pause;
+		chan->pattern_lo_idx = lo_idx;
+		chan->pattern_hi_idx = hi_idx;
+	}
+
+out_unlock:
+	mutex_unlock(&lpg->lock);
+	kfree(scaled);
+out_free_prep:
+	kfree(pattern.data);
 
-	ret = lpg_pattern_set(led, pattern, len, repeat);
 	if (ret < 0)
 		return ret;
 
-	led_mc_calc_color_components(mc, LED_FULL);
 	lpg_brightness_set(led, cdev, mc->subled_info);
 
 	return 0;
@@ -1174,11 +1284,9 @@ static int lpg_pattern_clear(struct lpg_led *led)
 
 	mutex_lock(&lpg->lock);
 
-	chan = led->channels[0];
-	lpg_lut_free(lpg, chan->pattern_lo_idx, chan->pattern_hi_idx);
-
 	for (i = 0; i < led->num_channels; i++) {
 		chan = led->channels[i];
+		lpg_lut_free(lpg, chan->pattern_lo_idx, chan->pattern_hi_idx);
 		lpg_sdam_configure_triggers(chan, 0);
 		lpg_clear_pbs_trigger(chan->lpg, chan->lut_mask);
 		chan->pattern_lo_idx = 0;

---
base-commit: 1795fd2dbe84ef4d393b69a0b2a3b371f810bde5
change-id: 20260605-lpg-rgb-color-balance-fix-82436649abf3

Best regards,
--  
Fenglin Wu <fenglin.wu@oss.qualcomm.com>

On Fri, Jun 05, 2026 at 01:18:24AM -0700, Fenglin Wu wrote:
> Currently, when the LED is configured as a RGB LED or a multi-color
> LED device, the same pattern is programmed for all LED channels
> regardless of the sub-led intensities when triggered by HW pattern.
> It results that the LED device is always working in a white-balanced
> mode regardless of the intensity settings.
> 
> To fix this, scale the pattern data according to the sub-led intensity
> and program the HW pattern separately for each LPG channel.
> 
> Fixes: 24e2d05d1b68 ("leds: Add driver for Qualcomm LPG")
> Fixes: 6ab1f766a80a ("leds: rgb: leds-qcom-lpg: Add support for PPG through single SDAM")
> Fixes: 5e9ff626861a ("leds: rgb: leds-qcom-lpg: Include support for PPG with dedicated LUT SDAM")
> Assisted-by: Claude:claude-4-6-sonnet
> Signed-off-by: Fenglin Wu <fenglin.wu@oss.qualcomm.com>
> ---
>  drivers/leds/rgb/leds-qcom-lpg.c | 174 +++++++++++++++++++++++++++++++--------
>  1 file changed, 141 insertions(+), 33 deletions(-)
> 
> diff --git a/drivers/leds/rgb/leds-qcom-lpg.c b/drivers/leds/rgb/leds-qcom-lpg.c
> index d7d6518de30f..ca84da563e09 100644
> --- a/drivers/leds/rgb/leds-qcom-lpg.c
> +++ b/drivers/leds/rgb/leds-qcom-lpg.c
> @@ -148,6 +148,24 @@ struct lpg_channel {
>  	unsigned int pattern_hi_idx;
>  };
>  
> +/**
> + * struct lpg_pattern - The LPG pattern normalized from the LED pattern
> + * @data:       The pattern data array (caller must kfree)
> + * @len:	number of entries to write to the LUT
> + * @delta_t:    common step duration in ms
> + * @lo_pause:   low-pause duration in ms
> + * @hi_pause:   high-pause duration in ms
> + * @ping_pong:  true if the pattern support reverse
> + */
> +struct lpg_pattern {
> +	struct led_pattern *data;

This looks like an overkill. Can you embed the struct here instead of
embedding a pointer?

> +	unsigned int len;
> +	unsigned int delta_t;
> +	unsigned int lo_pause;
> +	unsigned int hi_pause;
> +	bool ping_pong;
> +};
> +
>  /**
>   * struct lpg_led - logical LED object
>   * @lpg:		lpg context reference

-- 
With best wishes
Dmitry