Message-Id: <20251114-s2mu005-pmic-v1-10-9e3184d3a0c9@disroot.org>
Date: Fri, 14 Nov 2025 00:35:11 +0530
From: Kaustabh Chakraborty <kauschluss@...root.org>
To: Lee Jones <lee@...nel.org>, Pavel Machek <pavel@...nel.org>, 
 Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>, 
 Conor Dooley <conor+dt@...nel.org>, MyungJoo Ham <myungjoo.ham@...sung.com>, 
 Chanwoo Choi <cw00.choi@...sung.com>, Sebastian Reichel <sre@...nel.org>, 
 Krzysztof Kozlowski <krzk@...nel.org>, 
 André Draszik <andre.draszik@...aro.org>, 
 Alexandre Belloni <alexandre.belloni@...tlin.com>, 
 Jonathan Corbet <corbet@....net>
Cc: linux-leds@...r.kernel.org, devicetree@...r.kernel.org, 
 linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org, 
 linux-samsung-soc@...r.kernel.org, linux-rtc@...r.kernel.org, 
 linux-doc@...r.kernel.org, Kaustabh Chakraborty <kauschluss@...root.org>
Subject: [PATCH 10/13] leds: rgb: add support for Samsung S2M series PMIC
 RGB LED device

Add support for the RGB LEDs found in certain Samsung S2M series PMICs.
The device has three LED channels, controlled as a single device. These
LEDs are typically used as status indicators in mobile phones.

The driver includes initial support for the S2MU005 PMIC RGB LEDs.

Signed-off-by: Kaustabh Chakraborty <kauschluss@...root.org>
---
 drivers/leds/rgb/Kconfig        |  11 +
 drivers/leds/rgb/Makefile       |   1 +
 drivers/leds/rgb/leds-s2m-rgb.c | 462 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 474 insertions(+)

diff --git a/drivers/leds/rgb/Kconfig b/drivers/leds/rgb/Kconfig
index 222d943d826a..e38ba1bd434e 100644
--- a/drivers/leds/rgb/Kconfig
+++ b/drivers/leds/rgb/Kconfig
@@ -62,6 +62,17 @@ config LEDS_QCOM_LPG
 
 	  If compiled as a module, the module will be named leds-qcom-lpg.
 
+config LEDS_S2M_RGB
+	tristate "Samsung S2M series PMICs RGB LED support"
+	depends on LEDS_CLASS
+	depends on MFD_SEC_CORE
+	select REGMAP_IRQ
+	help
+	  This option enables support for the S2MU005 RGB LEDs. These
+	  devices have three LED channels, with 8-bit brightness control
+	  for each channel. It's usually found in mobile phones as
+	  status indicators.
+
 config LEDS_MT6370_RGB
 	tristate "LED Support for MediaTek MT6370 PMIC"
 	depends on MFD_MT6370
diff --git a/drivers/leds/rgb/Makefile b/drivers/leds/rgb/Makefile
index a501fd27f179..fc9d38fa60e1 100644
--- a/drivers/leds/rgb/Makefile
+++ b/drivers/leds/rgb/Makefile
@@ -5,4 +5,5 @@ obj-$(CONFIG_LEDS_KTD202X)		+= leds-ktd202x.o
 obj-$(CONFIG_LEDS_NCP5623)		+= leds-ncp5623.o
 obj-$(CONFIG_LEDS_PWM_MULTICOLOR)	+= leds-pwm-multicolor.o
 obj-$(CONFIG_LEDS_QCOM_LPG)		+= leds-qcom-lpg.o
+obj-$(CONFIG_LEDS_S2M_RGB)		+= leds-s2m-rgb.o
 obj-$(CONFIG_LEDS_MT6370_RGB)		+= leds-mt6370-rgb.o
diff --git a/drivers/leds/rgb/leds-s2m-rgb.c b/drivers/leds/rgb/leds-s2m-rgb.c
new file mode 100644
index 000000000000..2184ae0aec16
--- /dev/null
+++ b/drivers/leds/rgb/leds-s2m-rgb.c
@@ -0,0 +1,462 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * RGB LED Driver for Samsung S2M series PMICs.
+ *
+ * Copyright (c) 2015 Samsung Electronics Co., Ltd
+ * Copyright (c) 2025 Kaustabh Chakraborty <kauschluss@...root.org>
+ */
+
+#include <linux/container_of.h>
+#include <linux/device.h>
+#include <linux/led-class-multicolor.h>
+#include <linux/math.h>
+#include <linux/mfd/samsung/core.h>
+#include <linux/mfd/samsung/s2mu005.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+#include <linux/regmap.h>
+
+struct s2m_rgb {
+	struct device *dev;
+	struct regmap *regmap;
+	struct led_classdev_mc cdev;
+	struct mutex lock;
+	const struct s2m_rgb_spec *spec;
+	u8 ramp_up;
+	u8 ramp_dn;
+	u8 stay_hi;
+	u8 stay_lo;
+};
+
+struct s2m_rgb_spec {
+	int (*params_apply)(struct s2m_rgb *priv);
+	int (*params_reset)(struct s2m_rgb *priv);
+	const u32 *lut_ramp_up;
+	const size_t lut_ramp_up_len;
+	const u32 *lut_ramp_dn;
+	const size_t lut_ramp_dn_len;
+	const u32 *lut_stay_hi;
+	const size_t lut_stay_hi_len;
+	const u32 *lut_stay_lo;
+	const size_t lut_stay_lo_len;
+	const unsigned int max_brightness;
+};
+
+static struct led_classdev_mc *to_cdev_mc(struct led_classdev *cdev)
+{
+	return container_of(cdev, struct led_classdev_mc, led_cdev);
+}
+
+static struct s2m_rgb *to_rgb_priv(struct led_classdev_mc *cdev)
+{
+	return container_of(cdev, struct s2m_rgb, cdev);
+}
+
+static int s2m_rgb_lut_calc_timing(const u32 *lut, const size_t len,
+				   const u32 req_time, u8 *idx)
+{
+	int lo = 0;
+	int hi = len - 2;
+
+	/* Bounds checking */
+	if (req_time < lut[0] || req_time > lut[len - 1])
+		return -EINVAL;
+
+	/*
+	 * Perform a binary search to pick the best timing from the LUT.
+	 *
+	 * The search algorithm picks two consecutive elements of the
+	 * LUT and tries to search the pair between which the requested
+	 * time lies.
+	 */
+	while (lo <= hi) {
+		*idx = (lo + hi) / 2;
+
+		if ((lut[*idx] <= req_time) && (req_time <= lut[*idx + 1]))
+			break;
+
+		if ((req_time < lut[*idx]) && (req_time < lut[*idx + 1]))
+			hi = *idx - 1;
+		else
+			lo = *idx + 1;
+	}
+
+	/*
+	 * The searched timing is always less than the requested time. At
+	 * times, the succeeding timing in the LUT is closer thus more
+	 * accurate. Adjust the resulting value if that's the case.
+	 */
+	if (abs(req_time - lut[*idx]) > abs(lut[*idx + 1] - req_time))
+		(*idx)++;
+
+	return 0;
+}
+
+static int s2m_rgb_brightness_set(struct led_classdev *cdev,
+				  enum led_brightness value)
+{
+	struct s2m_rgb *priv = to_rgb_priv(to_cdev_mc(cdev));
+	int ret;
+
+	mutex_lock(&priv->lock);
+
+	led_mc_calc_color_components(&priv->cdev, value);
+
+	if (value == LED_OFF)
+		ret = priv->spec->params_reset(priv);
+	else
+		ret = priv->spec->params_apply(priv);
+
+	mutex_unlock(&priv->lock);
+
+	return ret;
+}
+
+static int s2m_rgb_pattern_set(struct led_classdev *cdev,
+			       struct led_pattern *pattern, u32 len, int repeat)
+{
+	struct s2m_rgb *priv = to_rgb_priv(to_cdev_mc(cdev));
+	int brightness_peak = 0;
+	u32 time_hi = 0;
+	u32 time_lo = 0;
+	bool ramp_up_en;
+	bool ramp_dn_en;
+	int ret;
+	int i;
+
+	/*
+	 * The typical pattern supported by this device can be
+	 * represented with the following graph:
+	 *
+	 *  255 T ''''''-.                         .-'''''''-.
+	 *      |         '.                     .'           '.
+	 *      |           \                   /               \
+	 *      |            '.               .'                 '.
+	 *      |              '-...........-'                     '-
+	 *    0 +----------------------------------------------------> time (s)
+	 *
+	 *       <---- HIGH ----><-- LOW --><-------- HIGH --------->
+	 *       <-----><-------><---------><-------><-----><------->
+	 *       stay_hi ramp_dn   stay_lo   ramp_up stay_hi ramp_dn
+	 *
+	 * There are two states, named HIGH and LOW. HIGH has a non-zero
+	 * brightness level, while LOW is of zero brightness. The
+	 * pattern provided should mention only one zero and non-zero
+	 * brightness level. The hardware always starts the pattern from
+	 * the HIGH state, as shown in the graph.
+	 *
+	 * The HIGH state can be divided in three somewhat equal timings:
+	 * ramp_up, stay_hi, and ramp_dn. The LOW state has only one
+	 * timing: stay_lo.
+	 */
+
+	/* Only indefinitely looping patterns are supported. */
+	if (repeat != -1)
+		return -EINVAL;
+
+	/* Pattern should consist of at least two tuples. */
+	if (len < 2)
+		return -EINVAL;
+
+	for (i = 0; i < len; i++) {
+		int brightness = pattern[i].brightness;
+		u32 delta_t = pattern[i].delta_t;
+
+		if (brightness) {
+			/*
+			 * The pattern shold define only one non-zero
+			 * brightness in the HIGH state. The device
+			 * doesn't have any provisions to handle
+			 * multiple peak brightness levels.
+			 */
+			if (brightness_peak && brightness_peak != brightness)
+				return -EINVAL;
+
+			brightness_peak = brightness;
+			time_hi += delta_t;
+			ramp_dn_en = !!delta_t;
+		} else {
+			time_lo += delta_t;
+			ramp_up_en = !!delta_t;
+		}
+	}
+
+	mutex_lock(&priv->lock);
+
+	/*
+	 * The timings ramp_up, stay_hi, and ramp_dn of the HIGH state
+	 * are roughly equal. Firstly, calculate and set timings for
+	 * ramp_up and ramp_dn (making sure they're exactly equal).
+	 */
+	priv->ramp_up = 0;
+	priv->ramp_dn = 0;
+
+	if (ramp_up_en) {
+		ret = s2m_rgb_lut_calc_timing(priv->spec->lut_ramp_up,
+					      priv->spec->lut_ramp_up_len,
+					      time_hi / 3, &priv->ramp_up);
+		if (ret < 0)
+			goto param_fail;
+	}
+
+	if (ramp_dn_en) {
+		ret = s2m_rgb_lut_calc_timing(priv->spec->lut_ramp_dn,
+					      priv->spec->lut_ramp_dn_len,
+					      time_hi / 3, &priv->ramp_dn);
+		if (ret < 0)
+			goto param_fail;
+	}
+
+	/*
+	 * Subtract the allocated ramp timings from time_hi (and also
+	 * making sure it doesn't underflow!). The remaining time is
+	 * allocated to stay_hi.
+	 */
+	time_hi -= min(time_hi, priv->spec->lut_ramp_up[priv->ramp_up]);
+	time_hi -= min(time_hi, priv->spec->lut_ramp_dn[priv->ramp_dn]);
+
+	ret = s2m_rgb_lut_calc_timing(priv->spec->lut_stay_hi,
+				      priv->spec->lut_stay_hi_len, time_hi,
+				      &priv->stay_hi);
+	if (ret < 0)
+		goto param_fail;
+
+	ret = s2m_rgb_lut_calc_timing(priv->spec->lut_stay_lo,
+				      priv->spec->lut_stay_lo_len, time_lo,
+				      &priv->stay_lo);
+	if (ret < 0)
+		goto param_fail;
+
+	led_mc_calc_color_components(&priv->cdev, brightness_peak);
+	ret = priv->spec->params_apply(priv);
+	if (ret < 0)
+		goto param_fail;
+
+	mutex_unlock(&priv->lock);
+
+	return 0;
+
+param_fail:
+	mutex_unlock(&priv->lock);
+	priv->ramp_up = 0;
+	priv->ramp_dn = 0;
+	priv->stay_hi = 0;
+	priv->stay_lo = 0;
+
+	return ret;
+}
+
+static int s2m_rgb_pattern_clear(struct led_classdev *cdev)
+{
+	struct s2m_rgb *priv = to_rgb_priv(to_cdev_mc(cdev));
+	int ret;
+
+	mutex_lock(&priv->lock);
+
+	ret = priv->spec->params_reset(priv);
+
+	mutex_unlock(&priv->lock);
+
+	return ret;
+}
+
+static int s2mu005_rgb_apply_params(struct s2m_rgb *priv)
+{
+	struct regmap *regmap = priv->regmap;
+	unsigned int ramp_val = 0;
+	unsigned int stay_val = 0;
+	int ret;
+	int i;
+
+	ramp_val |= FIELD_PREP(S2MU005_RGB_CH_RAMP_UP, priv->ramp_up);
+	ramp_val |= FIELD_PREP(S2MU005_RGB_CH_RAMP_DN, priv->ramp_dn);
+
+	stay_val |= FIELD_PREP(S2MU005_RGB_CH_STAY_HI, priv->stay_hi);
+	stay_val |= FIELD_PREP(S2MU005_RGB_CH_STAY_LO, priv->stay_lo);
+
+	ret = regmap_write(regmap, S2MU005_REG_RGB_EN, S2MU005_RGB_RESET);
+	if (ret < 0) {
+		dev_err(priv->dev, "failed to reset RGB LEDs\n");
+		return ret;
+	}
+
+	for (i = 0; i < priv->cdev.num_colors; i++) {
+		ret = regmap_write(regmap, S2MU005_REG_RGB_CH_CTRL(i),
+				   priv->cdev.subled_info[i].brightness);
+		if (ret < 0) {
+			dev_err(priv->dev, "failed to set LED brightness\n");
+			return ret;
+		}
+
+		ret = regmap_write(regmap, S2MU005_REG_RGB_CH_RAMP(i), ramp_val);
+		if (ret < 0) {
+			dev_err(priv->dev, "failed to set ramp timings\n");
+			return ret;
+		}
+
+		ret = regmap_write(regmap, S2MU005_REG_RGB_CH_STAY(i), stay_val);
+		if (ret < 0) {
+			dev_err(priv->dev, "failed to set stay timings\n");
+			return ret;
+		}
+	}
+
+	ret = regmap_update_bits(regmap, S2MU005_REG_RGB_EN, S2MU005_RGB_SLOPE,
+				 S2MU005_RGB_SLOPE_SMOOTH);
+	if (ret < 0) {
+		dev_err(priv->dev, "failed to set ramp slope\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static int s2mu005_rgb_reset_params(struct s2m_rgb *priv)
+{
+	struct regmap *regmap = priv->regmap;
+	int ret;
+
+	ret = regmap_write(regmap, S2MU005_REG_RGB_EN, S2MU005_RGB_RESET);
+	if (ret < 0) {
+		dev_err(priv->dev, "failed to reset RGB LEDs\n");
+		return ret;
+	}
+
+	priv->ramp_up = 0;
+	priv->ramp_dn = 0;
+	priv->stay_hi = 0;
+	priv->stay_lo = 0;
+
+	return 0;
+}
+
+static const u32 s2mu005_rgb_lut_ramp[] = {
+	0,	100,	200,	300,	400,	500,	600,	700,
+	800,	1000,	1200,	1400,	1600,	1800,	2000,	2200,
+};
+
+static const u32 s2mu005_rgb_lut_stay_hi[] = {
+	100,	200,	300,	400,	500,	750,	1000,	1250,
+	1500,	1750,	2000,	2250,	2500,	2750,	3000,	3250,
+};
+
+static const u32 s2mu005_rgb_lut_stay_lo[] = {
+	0,	500,	1000,	1500,	2000,	2500,	3000,	3500,
+	4000,	4500,	5000,	6000,	7000,	8000,	10000,	12000,
+};
+
+static const struct s2m_rgb_spec s2mu005_rgb_spec = {
+	.params_apply = s2mu005_rgb_apply_params,
+	.params_reset = s2mu005_rgb_reset_params,
+	.lut_ramp_up = s2mu005_rgb_lut_ramp,
+	.lut_ramp_up_len = ARRAY_SIZE(s2mu005_rgb_lut_ramp),
+	.lut_ramp_dn = s2mu005_rgb_lut_ramp,
+	.lut_ramp_dn_len = ARRAY_SIZE(s2mu005_rgb_lut_ramp),
+	.lut_stay_hi = s2mu005_rgb_lut_stay_hi,
+	.lut_stay_hi_len = ARRAY_SIZE(s2mu005_rgb_lut_stay_hi),
+	.lut_stay_lo = s2mu005_rgb_lut_stay_lo,
+	.lut_stay_lo_len = ARRAY_SIZE(s2mu005_rgb_lut_stay_lo),
+	.max_brightness = 255,
+};
+
+static struct mc_subled s2mu005_rgb_subled_info[] = {
+	{
+		.channel = 0,
+		.color_index = LED_COLOR_ID_BLUE,
+	}, {
+		.channel = 1,
+		.color_index = LED_COLOR_ID_GREEN,
+	}, {
+		.channel = 2,
+		.color_index = LED_COLOR_ID_RED,
+	},
+};
+
+static int s2m_rgb_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct sec_pmic_dev *pmic_drvdata = dev_get_drvdata(dev->parent);
+	struct s2m_rgb *priv;
+	struct led_init_data init_data = {};
+	int ret;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return dev_err_probe(dev, -ENOMEM, "failed to allocate driver private\n");
+
+	platform_set_drvdata(pdev, priv);
+	priv->dev = dev;
+	priv->regmap = pmic_drvdata->regmap_pmic;
+
+	switch (platform_get_device_id(pdev)->driver_data) {
+	case S2MU005:
+		priv->spec = &s2mu005_rgb_spec;
+		priv->cdev.subled_info = s2mu005_rgb_subled_info;
+		priv->cdev.num_colors = ARRAY_SIZE(s2mu005_rgb_subled_info);
+		break;
+	default:
+		return dev_err_probe(dev, -ENODEV,
+				     "device type %d is not supported by driver\n",
+				     pmic_drvdata->device_type);
+	}
+
+	priv->cdev.led_cdev.max_brightness = priv->spec->max_brightness;
+	priv->cdev.led_cdev.brightness_set_blocking = s2m_rgb_brightness_set;
+	priv->cdev.led_cdev.pattern_set = s2m_rgb_pattern_set;
+	priv->cdev.led_cdev.pattern_clear = s2m_rgb_pattern_clear;
+
+	ret = devm_mutex_init(dev, &priv->lock);
+	if (ret)
+		return dev_err_probe(dev, ret, "failed to create mutex lock\n");
+
+	init_data.fwnode = of_fwnode_handle(dev->of_node);
+	ret = devm_led_classdev_multicolor_register_ext(dev, &priv->cdev,
+							&init_data);
+	if (ret < 0)
+		return dev_err_probe(dev, ret, "failed to create LED device\n");
+
+	return 0;
+}
+
+static const struct platform_device_id s2m_rgb_id_table[] = {
+	{ "s2mu005-rgb", S2MU005 },
+	{ /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(platform, s2m_rgb_id_table);
+
+#ifdef CONFIG_OF
+/*
+ * Device is instantiated through parent MFD device and device matching
+ * is done through platform_device_id.
+ *
+ * However if device's DT node contains proper compatible and driver is
+ * built as a module, then the *module* matching will be done through DT
+ * aliases. This requires of_device_id table. In the same time this will
+ * not change the actual *device* matching so do not add .of_match_table.
+ */
+static const struct of_device_id s2m_rgb_of_match_table[] = {
+	{
+		.compatible = "samsung,s2mu005-rgb",
+		.data = (void *)S2MU005,
+	}, {
+		/* sentinel */
+	},
+};
+MODULE_DEVICE_TABLE(of, s2m_rgb_of_match_table);
+#endif
+
+static struct platform_driver s2m_rgb_driver = {
+	.driver = {
+		.name = "s2m-rgb",
+	},
+	.probe = s2m_rgb_probe,
+	.id_table = s2m_rgb_id_table,
+};
+module_platform_driver(s2m_rgb_driver);
+
+MODULE_DESCRIPTION("RGB LED Driver For Samsung S2M Series PMICs");
+MODULE_AUTHOR("Kaustabh Chakraborty <kauschluss@...root.org>");
+MODULE_LICENSE("GPL");

-- 
2.51.2

Powered by blists - more mailing lists