From ec961cf3241153e0f27d850f1bf0f172e7d27a21 Mon Sep 17 00:00:00 2001

From: Marijn Suijten <marijn.suijten@somainline.org>

Date: Mon, 15 Nov 2021 21:34:59 +0100

Subject: backlight: qcom-wled: Respect enabled-strings in set_brightness

Git-commit: ec961cf3241153e0f27d850f1bf0f172e7d27a21

Patch-mainline: v5.17-rc1

References: bsc#1152489

The hardware is capable of controlling any non-contiguous sequence of

LEDs specified in the DT using qcom,enabled-strings as u32

array, and this also follows from the DT-bindings documentation.  The

numbers specified in this array represent indices of the LED strings

that are to be enabled and disabled.

Its value is appropriately used to setup and enable string modules, but

completely disregarded in the set_brightness paths which only iterate

over the number of strings linearly.

Take an example where only string 2 is enabled with

qcom,enabled_strings=<2>: this string is appropriately enabled but

subsequent brightness changes would have only touched the zero'th

brightness register because num_strings is 1 here.  This is simply

addressed by looking up the string for this index in the enabled_strings

array just like the other codepaths that iterate over num_strings.

Likewise enabled_strings is now also used in the autodetection path for

consistent behaviour: when a list of strings is specified in DT only

those strings will be probed for autodetection, analogous to how the

number of strings that need to be probed is already bound by

qcom,num-strings.  After all autodetection uses the set_brightness

helpers to set an initial value, which could otherwise end up changing

brightness on a different set of strings.

Fixes: 775d2ffb4af6 ("backlight: qcom-wled: Restructure the driver for WLED3")

Fixes: 03b2b5e86986 ("backlight: qcom-wled: Add support for WLED4 peripheral")

Signed-off-by: Marijn Suijten <marijn.suijten@somainline.org>

Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@somainline.org>

Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>

Signed-off-by: Lee Jones <lee.jones@linaro.org>

Link: https://lore.kernel.org/r/20211115203459.1634079-10-marijn.suijten@somainline.org

Acked-by: Thomas Zimmermann <tzimmermann@suse.de>

---

 drivers/video/backlight/qcom-wled.c |   24 ++++++++++++++----------

 1 file changed, 14 insertions(+), 10 deletions(-)

--- a/drivers/video/backlight/qcom-wled.c

+++ b/drivers/video/backlight/qcom-wled.c

@@ -238,7 +238,8 @@ static int wled3_set_brightness(struct w

 	for (i = 0;  i < wled->cfg.num_strings; ++i) {

 		rc = regmap_bulk_write(wled->regmap, wled->ctrl_addr +

-				       WLED3_SINK_REG_BRIGHT(i), v, 2);

+				       WLED3_SINK_REG_BRIGHT(wled->cfg.enabled_strings[i]),

+				       v, 2);

 		if (rc < 0)

 			return rc;

 	}

@@ -261,7 +262,8 @@ static int wled4_set_brightness(struct w

 	for (i = 0;  i < wled->cfg.num_strings; ++i) {

 		rc = regmap_bulk_write(wled->regmap, wled->sink_addr +

-				       WLED4_SINK_REG_BRIGHT(i), v, 2);

+				       WLED4_SINK_REG_BRIGHT(wled->cfg.enabled_strings[i]),

+				       v, 2);

 		if (rc < 0)

 			return rc;

 	}

@@ -559,7 +561,7 @@ unlock_mutex:

 static void wled_auto_string_detection(struct wled *wled)

 {

-	int rc = 0, i, delay_time_us;

+	int rc = 0, i, j, delay_time_us;

 	u32 sink_config = 0;

 	u8 sink_test = 0, sink_valid = 0, val;

 	bool fault_set;

@@ -606,14 +608,15 @@ static void wled_auto_string_detection(s

 	/* Iterate through the strings one by one */

 	for (i = 0; i < wled->cfg.num_strings; i++) {

-		sink_test = BIT((WLED4_SINK_REG_CURR_SINK_SHFT + i));

+		j = wled->cfg.enabled_strings[i];

+		sink_test = BIT((WLED4_SINK_REG_CURR_SINK_SHFT + j));

 		/* Enable feedback control */

 		rc = regmap_write(wled->regmap, wled->ctrl_addr +

-				  WLED3_CTRL_REG_FEEDBACK_CONTROL, i + 1);

+				  WLED3_CTRL_REG_FEEDBACK_CONTROL, j + 1);

 		if (rc < 0) {

 			dev_err(wled->dev, "Failed to enable feedback for SINK %d rc = %d\n",

-				i + 1, rc);

+				j + 1, rc);

 			goto failed_detect;

 		}

@@ -622,7 +625,7 @@ static void wled_auto_string_detection(s

 				  WLED4_SINK_REG_CURR_SINK, sink_test);

 		if (rc < 0) {

 			dev_err(wled->dev, "Failed to configure SINK %d rc=%d\n",

-				i + 1, rc);

+				j + 1, rc);

 			goto failed_detect;

 		}

@@ -649,7 +652,7 @@ static void wled_auto_string_detection(s

 		if (fault_set)

 			dev_dbg(wled->dev, "WLED OVP fault detected with SINK %d\n",

-				i + 1);

+				j + 1);

 		else

 			sink_valid |= sink_test;

@@ -689,15 +692,16 @@ static void wled_auto_string_detection(s

 	/* Enable valid sinks */

 	if (wled->version == 4) {

 		for (i = 0; i < wled->cfg.num_strings; i++) {

+			j = wled->cfg.enabled_strings[i];

 			if (sink_config &

-			    BIT(WLED4_SINK_REG_CURR_SINK_SHFT + i))

+			    BIT(WLED4_SINK_REG_CURR_SINK_SHFT + j))

 				val = WLED4_SINK_REG_STR_MOD_MASK;

 			else

 				/* Disable modulator_en for unused sink */

 				val = 0;

 			rc = regmap_write(wled->regmap, wled->sink_addr +

-					  WLED4_SINK_REG_STR_MOD_EN(i), val);

+					  WLED4_SINK_REG_STR_MOD_EN(j), val);

 			if (rc < 0) {

 				dev_err(wled->dev, "Failed to configure MODULATOR_EN rc=%d\n",

 					rc);