--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * RGB LED Driver for Samsung S2M series PMICs.
+ *
+ * Copyright (c) 2015 Samsung Electronics Co., Ltd
+ * Copyright (c) 2026 Kaustabh Chakraborty <kauschluss@disroot.org>
+ */
+
+#include <linux/container_of.h>
+#include <linux/led-class-multicolor.h>
+#include <linux/mfd/samsung/core.h>
+#include <linux/mfd/samsung/s2mu005.h>
+#include <linux/minmax.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+struct s2m_rgb {
+ struct device *dev;
+ struct regmap *regmap;
+ struct led_classdev_mc mc;
+ /*
+ * The mutex object prevents race conditions when evaluation and
+ * application of LED pattern state.
+ */
+ struct mutex lock;
+ /*
+ * State variables representing the current LED pattern, these only to
+ * be accessed when lock is held.
+ */
+ u8 ramp_up;
+ u8 ramp_dn;
+ u8 stay_hi;
+ u8 stay_lo;
+};
+
+static struct led_classdev_mc *to_s2m_mc(struct led_classdev *cdev)
+{
+ return container_of(cdev, struct led_classdev_mc, led_cdev);
+}
+
+static struct s2m_rgb *to_s2m_rgb(struct led_classdev_mc *mc)
+{
+ return container_of(mc, struct s2m_rgb, mc);
+}
+
+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 int s2mu005_rgb_apply_params(struct s2m_rgb *rgb)
+{
+ struct regmap *regmap = rgb->regmap;
+ unsigned int ramp_val = 0;
+ unsigned int stay_val = 0;
+ int ret;
+
+ ramp_val |= FIELD_PREP(S2MU005_RGB_CH_RAMP_UP, rgb->ramp_up);
+ ramp_val |= FIELD_PREP(S2MU005_RGB_CH_RAMP_DN, rgb->ramp_dn);
+
+ stay_val |= FIELD_PREP(S2MU005_RGB_CH_STAY_HI, rgb->stay_hi);
+ stay_val |= FIELD_PREP(S2MU005_RGB_CH_STAY_LO, rgb->stay_lo);
+
+ ret = regmap_write(regmap, S2MU005_REG_RGB_EN, S2MU005_RGB_RESET);
+ if (ret) {
+ dev_err(rgb->dev, "failed to reset RGB LEDs\n");
+ return ret;
+ }
+
+ for (int i = 0; i < rgb->mc.num_colors; i++) {
+ ret = regmap_write(regmap, S2MU005_REG_RGB_CH_CTRL(i),
+ rgb->mc.subled_info[i].brightness);
+ if (ret) {
+ dev_err(rgb->dev, "failed to set LED brightness\n");
+ return ret;
+ }
+
+ ret = regmap_write(regmap, S2MU005_REG_RGB_CH_RAMP(i), ramp_val);
+ if (ret) {
+ dev_err(rgb->dev, "failed to set ramp timings\n");
+ return ret;
+ }
+
+ ret = regmap_write(regmap, S2MU005_REG_RGB_CH_STAY(i), stay_val);
+ if (ret) {
+ dev_err(rgb->dev, "failed to set stay timings\n");
+ return ret;
+ }
+ }
+
+ ret = regmap_write(regmap, S2MU005_REG_RGB_EN, S2MU005_RGB_SLOPE_SMOOTH);
+ if (ret) {
+ dev_err(rgb->dev, "failed to set ramp slope\n");
+ return ret;
+ }
+
+ return 0;
+}
+
+static int s2mu005_rgb_reset_params(struct s2m_rgb *rgb)
+{
+ struct regmap *regmap = rgb->regmap;
+ int ret;
+
+ ret = regmap_write(regmap, S2MU005_REG_RGB_EN, S2MU005_RGB_RESET);
+ if (ret) {
+ dev_err(rgb->dev, "failed to reset RGB LEDs\n");
+ return ret;
+ }
+
+ rgb->ramp_up = 0;
+ rgb->ramp_dn = 0;
+ rgb->stay_hi = 0;
+ rgb->stay_lo = 0;
+
+ return 0;
+}
+
+/*
+ * s2m_rgb_lut_get_closest_duration - find closest duration in look-up table
+ * @lut: the look-up table to search for the closest timing
+ * @len: number of elements in the look-up table array
+ * @duration: the timing duration requested
+ *
+ * This function does a binary search on the given array, and finds the closest
+ * value to the requested timing. It is expected that the look-up table to be
+ * provided, is already sorted.
+ *
+ * This function returns a negative error code, or a non-negative index of the
+ * value in the look-up table closest to the one requested.
+ */
+static int s2m_rgb_lut_get_closest_duration(const u32 *lut, const size_t len, const u32 duration)
+{
+ u32 closest_distance = abs(duration - lut[0]);
+ int closest_index = 0;
+ int lo = 0;
+ int hi = len - 1;
+
+ /*
+ * Allow a small amount of extrapolation beyond the highest timing value.
+ *
+ * Consider x and y to be the two last values in the table, and x < y.
+ * Since (y - x) / 2 integers, in the range [x + (y - x) / 2, y)
+ * returns y as the closest, allow extrapolation for the succeeding
+ * (y - x) / 2 integers as well, viz, up to (y, y + (y - x) / 2].
+ * Anything beyond that is invalid.
+ */
+ if (len >= 2 && duration > lut[len - 1] + (lut[len - 1] - lut[len - 2]) / 2)
+ return -EINVAL;
+
+ while (lo <= hi) {
+ int mid = lo + (hi - lo) / 2;
+
+ /* Narrow down search window as per binary-search algorithm. */
+ if (duration < lut[mid])
+ hi = mid - 1;
+ else
+ lo = mid + 1;
+
+ if (abs(duration - lut[mid]) < closest_distance) {
+ closest_distance = abs(duration - lut[mid]);
+ closest_index = mid;
+ }
+ }
+
+ return closest_index;
+}
+
+static int s2m_rgb_pattern_set(struct led_classdev *cdev, struct led_pattern *pattern, u32 len,
+ int repeat)
+{
+ struct s2m_rgb *rgb = to_s2m_rgb(to_s2m_mc(cdev));
+ const u32 *lut_ramp_up, *lut_ramp_dn, *lut_stay_hi, *lut_stay_lo;
+ size_t lut_ramp_up_len, lut_ramp_dn_len, lut_stay_hi_len, lut_stay_lo_len;
+ int brightness_peak = 0;
+ u32 time_hi = 0, time_lo = 0;
+ bool ramp_up_en = false, ramp_dn_en = false;
+ int ret;
+
+ /*
+ * 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 (int i = 0; i < len; i++) {
+ int brightness = pattern[i].brightness;
+ u32 delta_t = pattern[i].delta_t;
+
+ if (brightness) {
+ /*
+ * The pattern should 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;
+ }
+ }
+
+ /* LUTs are specific to device variant. */
+ 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);
+
+ mutex_lock(&rgb->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).
+ */
+ rgb->ramp_up = 0;
+ rgb->ramp_dn = 0;
+
+ if (ramp_up_en) {
+ ret = s2m_rgb_lut_get_closest_duration(lut_ramp_up, lut_ramp_up_len, time_hi / 3);
+ if (ret < 0)
+ goto param_fail;
+ rgb->ramp_up = (u8)ret;
+ }
+
+ if (ramp_dn_en) {
+ ret = s2m_rgb_lut_get_closest_duration(lut_ramp_dn, lut_ramp_dn_len, time_hi / 3);
+ if (ret < 0)
+ goto param_fail;
+ rgb->ramp_dn = (u8)ret;
+ }
+
+ /*
+ * 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, lut_ramp_up[rgb->ramp_up]);
+ time_hi -= min(time_hi, lut_ramp_dn[rgb->ramp_dn]);
+
+ ret = s2m_rgb_lut_get_closest_duration(lut_stay_hi, lut_stay_hi_len, time_hi);
+ if (ret < 0)
+ goto param_fail;
+ rgb->stay_hi = (u8)ret;
+
+ ret = s2m_rgb_lut_get_closest_duration(lut_stay_lo, lut_stay_lo_len, time_lo);
+ if (ret < 0)
+ goto param_fail;
+ rgb->stay_lo = (u8)ret;
+
+ led_mc_calc_color_components(&rgb->mc, brightness_peak);
+ /* Apply params with variant-specific implementation. */
+ ret = s2mu005_rgb_apply_params(rgb);
+ if (ret)
+ goto param_fail;
+
+ mutex_unlock(&rgb->lock);
+
+ return 0;
+
+param_fail:
+ rgb->ramp_up = 0;
+ rgb->ramp_dn = 0;
+ rgb->stay_hi = 0;
+ rgb->stay_lo = 0;
+
+ mutex_unlock(&rgb->lock);
+
+ return ret;
+}
+
+static int s2m_rgb_pattern_clear(struct led_classdev *cdev)
+{
+ struct s2m_rgb *rgb = to_s2m_rgb(to_s2m_mc(cdev));
+ int ret = 0;
+
+ mutex_lock(&rgb->lock);
+
+ /* Reset params with variant-specific implementation. */
+ ret = s2mu005_rgb_reset_params(rgb);
+
+ mutex_unlock(&rgb->lock);
+
+ return ret;
+}
+
+static int s2m_rgb_brightness_set(struct led_classdev *cdev, enum led_brightness value)
+{
+ struct s2m_rgb *rgb = to_s2m_rgb(to_s2m_mc(cdev));
+ int ret = 0;
+
+ if (!value)
+ return s2m_rgb_pattern_clear(cdev);
+
+ mutex_lock(&rgb->lock);
+
+ led_mc_calc_color_components(&rgb->mc, value);
+ /* Apply params with variant-specific implementation. */
+ ret = s2mu005_rgb_apply_params(rgb);
+
+ mutex_unlock(&rgb->lock);
+
+ return ret;
+}
+
+static const 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 *rgb;
+ struct led_init_data init_data = {};
+ int ret;
+
+ rgb = devm_kzalloc(dev, sizeof(*rgb), GFP_KERNEL);
+ if (!rgb)
+ return -ENOMEM;
+
+ platform_set_drvdata(pdev, rgb);
+ rgb->dev = dev;
+ rgb->regmap = pmic_drvdata->regmap_pmic;
+
+ /* Configure variant-specific details. */
+ rgb->mc.num_colors = ARRAY_SIZE(s2mu005_rgb_subled_info);
+ rgb->mc.subled_info = devm_kmemdup(dev, s2mu005_rgb_subled_info,
+ sizeof(s2mu005_rgb_subled_info), GFP_KERNEL);
+ if (!rgb->mc.subled_info)
+ return -ENOMEM;
+
+ rgb->mc.led_cdev.max_brightness = 255;
+ rgb->mc.led_cdev.brightness_set_blocking = s2m_rgb_brightness_set;
+ rgb->mc.led_cdev.pattern_set = s2m_rgb_pattern_set;
+ rgb->mc.led_cdev.pattern_clear = s2m_rgb_pattern_clear;
+
+ ret = devm_mutex_init(dev, &rgb->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, &rgb->mc, &init_data);
+ if (ret)
+ 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);
+
+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);
+
+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@disroot.org>");
+MODULE_LICENSE("GPL");
projects / thirdparty / kernel / linux.git / commitdiff
