[PATCH 05/15] HID: hid-oxp: fix multicolor LED intensity scaling

[Andrei Aldea <andrei1998@gmail.com>]

The controller accepts eight-bit RGB components, but the sub-LED channel
maximum currently inherits the 0-100 overall brightness range. This
prevents userspace from selecting channel intensities above 100.

Set each channel maximum to 255 and use the multicolor LED core helper to
scale components with the requested brightness. This also replaces the
private truncating calculation with the LED core's rounded calculation.

Keep the existing Gen1 and Gen2 color packet layouts unchanged.

Fixes: 84910c459d65 ("HID: hid-oxp: Add OneXPlayer configuration driver")
Assisted-by: LLM
Reviewed-by: Derek J. Clark <derekjohn.clark@gmail.com>
Signed-off-by: Andrei Aldea <andrei1998@gmail.com>
---
 drivers/hid/hid-oxp.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/hid/hid-oxp.c b/drivers/hid/hid-oxp.c
index c3cfa95..bee1317 100644
--- a/drivers/hid/hid-oxp.c
+++ b/drivers/hid/hid-oxp.c
@@ -1088,7 +1088,6 @@ static ssize_t oxp_rgb_status_show(void)
 
 static int oxp_rgb_color_set(void)
 {
-	u8 max_br = drvdata.led_mc->led_cdev.max_brightness;
 	u8 br = drvdata.led_mc->led_cdev.brightness;
 	u16 up = get_usage_page(drvdata.hdev);
 	u8 green, red, blue;
@@ -1096,9 +1095,10 @@ static int oxp_rgb_color_set(void)
 	u8 *data;
 	int i;
 
-	red = br * drvdata.led_mc->subled_info[0].intensity / max_br;
-	green = br * drvdata.led_mc->subled_info[1].intensity / max_br;
-	blue = br * drvdata.led_mc->subled_info[2].intensity / max_br;
+	led_mc_calc_color_components(drvdata.led_mc, br);
+	red = drvdata.led_mc->subled_info[0].brightness;
+	green = drvdata.led_mc->subled_info[1].brightness;
+	blue = drvdata.led_mc->subled_info[2].brightness;
 
 	switch (up) {
 	case GEN1_USAGE_PAGE:
@@ -1383,16 +1383,19 @@ static struct mc_subled oxp_rgb_subled_info[] = {
 	{
 		.color_index = LED_COLOR_ID_RED,
 		.intensity = 0x24,
+		.max_intensity = 0xff,
 		.channel = 0x1,
 	},
 	{
 		.color_index = LED_COLOR_ID_GREEN,
 		.intensity = 0x22,
+		.max_intensity = 0xff,
 		.channel = 0x2,
 	},
 	{
 		.color_index = LED_COLOR_ID_BLUE,
 		.intensity = 0x99,
+		.max_intensity = 0xff,
 		.channel = 0x3,
 	},
 };