leds: max5970: Add support for max5970

The MAX5970 is hot swap controller and has 4 indication LED.
Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Signed-off-by: Naresh Solanki <Naresh.Solanki@9elements.com>
Link: https://lore.kernel.org/r/20231123132803.1107174-1-naresh.solanki@9elements.comSigned-off-by: Lee Jones <lee@kernel.org>

drivers/leds/Kconfig

@@ -648,6 +648,17 @@ config LEDS_ADP5520
 	  To compile this driver as a module, choose M here: the module will
 	  be called leds-adp5520.
 
+config LEDS_MAX5970
+	tristate "LED Support for Maxim 5970"
+	depends on LEDS_CLASS
+	depends on MFD_MAX5970
+	help
+	  This option enables support for the Maxim MAX5970 & MAX5978 smart
+	  switch indication LEDs via the I2C bus.
+
+	  To compile this driver as a module, choose M here: the module will
+	  be called leds-max5970.
+
 config LEDS_MC13783
 	tristate "LED Support for MC13XXX PMIC"
 	depends on LEDS_CLASS

drivers/leds/Makefile

@@ -56,6 +56,7 @@ obj-$(CONFIG_LEDS_LP8501)		+= leds-lp8501.o
 obj-$(CONFIG_LEDS_LP8788)		+= leds-lp8788.o
 obj-$(CONFIG_LEDS_LP8860)		+= leds-lp8860.o
 obj-$(CONFIG_LEDS_LT3593)		+= leds-lt3593.o
+obj-$(CONFIG_LEDS_MAX5970)		+= leds-max5970.o
 obj-$(CONFIG_LEDS_MAX77650)		+= leds-max77650.o
 obj-$(CONFIG_LEDS_MAX8997)		+= leds-max8997.o
 obj-$(CONFIG_LEDS_MC13783)		+= leds-mc13783.o

drivers/leds/leds-max5970.c

+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Device driver for leds in MAX5970 and MAX5978 IC
+ *
+ * Copyright (c) 2022 9elements GmbH
+ *
+ * Author: Patrick Rudolph <patrick.rudolph@9elements.com>
+ */
+
+#include <linux/leds.h>
+#include <linux/mfd/max5970.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+#define ldev_to_maxled(c)       container_of(c, struct max5970_led, cdev)
+
+struct max5970_led {
+	struct device *dev;
+	struct regmap *regmap;
+	struct led_classdev cdev;
+	unsigned int index;
+};
+
+static int max5970_led_set_brightness(struct led_classdev *cdev,
+				      enum led_brightness brightness)
+{
+	struct max5970_led *ddata = ldev_to_maxled(cdev);
+	int ret, val;
+
+	/* Set/clear corresponding bit for given led index */
+	val = !brightness ? BIT(ddata->index) : 0;
+
+	ret = regmap_update_bits(ddata->regmap, MAX5970_REG_LED_FLASH, BIT(ddata->index), val);
+	if (ret < 0)
+		dev_err(cdev->dev, "failed to set brightness %d", ret);
+
+	return ret;
+}
+
+static int max5970_led_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *np = dev_of_node(dev->parent);
+	struct regmap *regmap;
+	struct device_node *led_node, *child;
+	struct max5970_led *ddata;
+	int ret = -ENODEV, num_leds = 0;
+
+	regmap = dev_get_regmap(pdev->dev.parent, NULL);
+	if (!regmap)
+		return -ENODEV;
+
+	led_node = of_get_child_by_name(np, "leds");
+	if (!led_node)
+		return -ENODEV;
+
+	for_each_available_child_of_node(led_node, child) {
+		u32 reg;
+
+		if (of_property_read_u32(child, "reg", &reg))
+			continue;
+
+		if (reg >= MAX5970_NUM_LEDS) {
+			dev_err(dev, "invalid LED (%u >= %d)\n", reg, MAX5970_NUM_LEDS);
+			continue;
+		}
+
+		ddata = devm_kzalloc(dev, sizeof(*ddata), GFP_KERNEL);
+		if (!ddata) {
+			of_node_put(child);
+			return -ENOMEM;
+		}
+
+		ddata->index = reg;
+		ddata->regmap = regmap;
+		ddata->dev = dev;
+
+		if (of_property_read_string(child, "label", &ddata->cdev.name))
+			ddata->cdev.name = child->name;
+
+		ddata->cdev.max_brightness = 1;
+		ddata->cdev.brightness_set_blocking = max5970_led_set_brightness;
+		ddata->cdev.default_trigger = "none";
+
+		ret = devm_led_classdev_register(dev, &ddata->cdev);
+		if (ret < 0) {
+			of_node_put(child);
+			dev_err(dev, "Failed to initialize LED %u\n", reg);
+			return ret;
+		}
+		num_leds++;
+	}
+
+	return ret;
+}
+
+static struct platform_driver max5970_led_driver = {
+	.driver = {
+		.name = "max5970-led",
+	},
+	.probe = max5970_led_probe,
+};
+
+module_platform_driver(max5970_led_driver);
+MODULE_AUTHOR("Patrick Rudolph <patrick.rudolph@9elements.com>");
+MODULE_AUTHOR("Naresh Solanki <Naresh.Solanki@9elements.com>");
+MODULE_DESCRIPTION("MAX5970_hot-swap controller LED driver");
+MODULE_LICENSE("GPL");