[PATCH v3 2/2] leds: Add NCP5623 multi-led driver

[Abdel Alkuor]

NCP5623 is DC-DC multi-LEDs driver which has three PWMs that can be
programmed up to 32 steps giving 32768 colors hue.

NCP5623 driver supports gradual dimming upward/downward with programmable
delays. Also, the driver supports driving a single LED or multi-LED
like RGB.

Signed-off-by: Abdel Alkuor <alkuor@xxxxxxxxx>
---
Changes in v3:
 - Add defines for magic numbers
 - Fix code style
 - Add a comment how ncp->delay is calculated
 - Don't free mc_node when probe is successful
 - Link to v2: https://lore.kernel.org/all/20240217230956.630522-2-alkuor@xxxxxxxxx/

Changes in v2:
 - Remove all custom attributes and use hw pattern instead
 - Remove filename from the driver description
 - Fix coding style
 - Destroy the muttex in shutdown callback
 - Register mcled device using none devm version as unregistering mcled device
   calls ncp5632_set_led which uses mutex hence we need to make sure the
   mutex is still available during the unregistering process.
 - Link to v1: https://lore.kernel.org/linux-kernel/20240208130115.GM689448@xxxxxxxxxx/T/
 drivers/leds/rgb/Kconfig        |  11 ++
 drivers/leds/rgb/Makefile       |   1 +
 drivers/leds/rgb/leds-ncp5623.c | 271 ++++++++++++++++++++++++++++++++
 3 files changed, 283 insertions(+)
 create mode 100644 drivers/leds/rgb/leds-ncp5623.c

diff --git a/drivers/leds/rgb/Kconfig b/drivers/leds/rgb/Kconfig
index a6a21f564673..81ab6a526a78 100644
--- a/drivers/leds/rgb/Kconfig
+++ b/drivers/leds/rgb/Kconfig
@@ -27,6 +27,17 @@ config LEDS_KTD202X
 	  To compile this driver as a module, choose M here: the module
 	  will be called leds-ktd202x.
 
+config LEDS_NCP5623
+	tristate "LED support for NCP5623"
+	depends on I2C
+	depends on OF
+	help
+	  This option enables support for ON semiconductor NCP5623
+	  Triple Output I2C Controlled RGB LED Driver.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called leds-ncp5623.
+
 config LEDS_PWM_MULTICOLOR
 	tristate "PWM driven multi-color LED Support"
 	depends on PWM
diff --git a/drivers/leds/rgb/Makefile b/drivers/leds/rgb/Makefile
index 243f31e4d70d..a501fd27f179 100644
--- a/drivers/leds/rgb/Makefile
+++ b/drivers/leds/rgb/Makefile
@@ -2,6 +2,7 @@
 
 obj-$(CONFIG_LEDS_GROUP_MULTICOLOR)	+= leds-group-multicolor.o
 obj-$(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_MT6370_RGB)		+= leds-mt6370-rgb.o
diff --git a/drivers/leds/rgb/leds-ncp5623.c b/drivers/leds/rgb/leds-ncp5623.c
new file mode 100644
index 000000000000..b669c55c5483
--- /dev/null
+++ b/drivers/leds/rgb/leds-ncp5623.c
@@ -0,0 +1,271 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * NCP5623 Multi-LED Driver
+ *
+ * Author: Abdel Alkuor <alkuor@xxxxxxxxx>
+ * Datasheet: https://www.onsemi.com/pdf/datasheet/ncp5623-d.pdf
+ */
+
+#include <linux/i2c.h>
+#include <linux/module.h>
+
+#include <linux/led-class-multicolor.h>
+
+#define NCP5623_FUNCTION_OFFSET		0x5
+#define NCP5623_REG(x)			((x) << NCP5623_FUNCTION_OFFSET)
+
+#define NCP5623_SHUTDOWN_REG		NCP5623_REG(0x0)
+#define NCP5623_ILED_REG		NCP5623_REG(0x1)
+#define NCP5623_PWM_REG(index)		NCP5623_REG(0x2 + (index))
+#define NCP5623_UPWARD_STEP_REG		NCP5623_REG(0x5)
+#define NCP5623_DOWNWARD_STEP_REG	NCP5623_REG(0x6)
+#define NCP5623_DIMMING_TIME_REG	NCP5623_REG(0x7)
+
+#define NCP5623_MAX_BRIGHTNESS		0x1f
+#define NCP5623_MAX_DIM_TIME		240 /* ms */
+#define NCP5623_DIM_STEP		8   /* ms */
+
+struct ncp5623 {
+	struct i2c_client *client;
+	struct led_classdev_mc mc_dev;
+	struct mutex lock;
+
+	int current_brightness;
+	unsigned long delay;
+};
+
+static int ncp5623_write(struct i2c_client *client, u8 reg, u8 data)
+{
+	return i2c_smbus_write_byte_data(client, reg | data, 0);
+}
+
+static int ncp5623_brightness_set(struct led_classdev *cdev,
+				  enum led_brightness brightness)
+{
+	struct led_classdev_mc *mc_cdev = lcdev_to_mccdev(cdev);
+	struct ncp5623 *ncp = container_of(mc_cdev, struct ncp5623, mc_dev);
+	int ret;
+
+	guard(mutex)(&ncp->lock);
+
+	if (ncp->delay && time_is_after_jiffies(ncp->delay))
+		return -EBUSY;
+
+	ncp->delay = 0;
+
+	for (int i = 0; i < mc_cdev->num_colors; i++) {
+		ret = ncp5623_write(ncp->client,
+				    NCP5623_PWM_REG(mc_cdev->subled_info[i].channel),
+				    min(mc_cdev->subled_info[i].intensity,
+					NCP5623_MAX_BRIGHTNESS));
+		if (ret)
+			return ret;
+	}
+
+	ret = ncp5623_write(ncp->client, NCP5623_DIMMING_TIME_REG, 0);
+	if (ret)
+		return ret;
+
+	ret = ncp5623_write(ncp->client, NCP5623_ILED_REG, brightness);
+	if (ret)
+		return ret;
+
+	ncp->current_brightness = brightness;
+
+	return 0;
+}
+
+static int ncp5623_pattern_set(struct led_classdev *cdev,
+			       struct led_pattern *pattern,
+			       u32 len, int repeat)
+{
+	struct led_classdev_mc *mc_cdev = lcdev_to_mccdev(cdev);
+	struct ncp5623 *ncp = container_of(mc_cdev, struct ncp5623, mc_dev);
+	int brightness_diff;
+	u8 reg;
+	int ret;
+
+	guard(mutex)(&ncp->lock);
+
+	if (ncp->delay && time_is_after_jiffies(ncp->delay))
+		return -EBUSY;
+
+	ncp->delay = 0;
+
+	if (pattern[0].delta_t > NCP5623_MAX_DIM_TIME ||
+	   (pattern[0].delta_t % NCP5623_DIM_STEP) != 0)
+		return -EINVAL;
+
+	brightness_diff = pattern[0].brightness - ncp->current_brightness;
+
+	if (brightness_diff == 0)
+		return 0;
+
+	if (pattern[0].delta_t) {
+		if (brightness_diff > 0)
+			reg = NCP5623_UPWARD_STEP_REG;
+		else
+			reg = NCP5623_DOWNWARD_STEP_REG;
+	} else {
+		reg = NCP5623_ILED_REG;
+	}
+
+	ret = ncp5623_write(ncp->client, reg,
+			    min(pattern[0].brightness, NCP5623_MAX_BRIGHTNESS));
+	if (ret)
+		return ret;
+
+	ret = ncp5623_write(ncp->client,
+			    NCP5623_DIMMING_TIME_REG,
+			    pattern[0].delta_t / NCP5623_DIM_STEP);
+	if (ret)
+		return ret;
+
+	/*
+	 * During testing, when the brightness difference is 1, for some
+	 * unknown reason, the time factor it takes to change to the new
+	 * value is the longest time possible. Otherwise, the time factor
+	 * is simply the brightness difference.
+	 *
+	 * For example:
+	 * current_brightness = 20 and new_brightness = 21 then the time it
+	 * takes to set the new brightness increments to the maximum possible
+	 * brightness from 20 then from 0 to 21.
+	 * time_factor = max_brightness - 20 + 21
+	 */
+	if (abs(brightness_diff) == 1)
+		ncp->delay = NCP5623_MAX_BRIGHTNESS + brightness_diff;
+	else
+		ncp->delay = abs(brightness_diff);
+
+	ncp->delay = msecs_to_jiffies(ncp->delay * pattern[0].delta_t) + jiffies;
+
+	ncp->current_brightness = pattern[0].brightness;
+
+	return 0;
+}
+
+static int ncp5623_pattern_clear(struct led_classdev *led_cdev)
+{
+	return 0;
+}
+
+static int ncp5623_probe(struct i2c_client *client)
+{
+	struct device *dev = &client->dev;
+	struct fwnode_handle *mc_node, *led_node;
+	struct led_init_data init_data = { };
+	int num_subleds = 0;
+	struct ncp5623 *ncp;
+	struct mc_subled *subled_info;
+	u32 color_index;
+	u32 reg;
+	int ret;
+
+	ncp = devm_kzalloc(dev, sizeof(*ncp), GFP_KERNEL);
+	if (!ncp)
+		return -ENOMEM;
+
+	ncp->client = client;
+
+	mc_node = device_get_named_child_node(dev, "multi-led");
+	if (!mc_node)
+		return -EINVAL;
+
+	fwnode_for_each_child_node(mc_node, led_node)
+		num_subleds++;
+
+	subled_info = devm_kcalloc(dev, num_subleds, sizeof(*subled_info), GFP_KERNEL);
+	if (!subled_info) {
+		ret = -ENOMEM;
+		goto release_mc_node;
+	}
+
+	fwnode_for_each_available_child_node(mc_node, led_node) {
+		ret = fwnode_property_read_u32(led_node, "color", &color_index);
+		if (ret) {
+			fwnode_handle_put(led_node);
+			goto release_mc_node;
+		}
+
+		ret = fwnode_property_read_u32(led_node, "reg", &reg);
+		if (ret) {
+			fwnode_handle_put(led_node);
+			goto release_mc_node;
+		}
+
+		subled_info[ncp->mc_dev.num_colors].channel = reg;
+		subled_info[ncp->mc_dev.num_colors++].color_index = color_index;
+	}
+
+	init_data.fwnode = mc_node;
+
+	ncp->mc_dev.led_cdev.max_brightness = NCP5623_MAX_BRIGHTNESS;
+	ncp->mc_dev.subled_info = subled_info;
+	ncp->mc_dev.led_cdev.brightness_set_blocking = ncp5623_brightness_set;
+	ncp->mc_dev.led_cdev.pattern_set = ncp5623_pattern_set;
+	ncp->mc_dev.led_cdev.pattern_clear = ncp5623_pattern_clear;
+	ncp->mc_dev.led_cdev.default_trigger = "pattern";
+
+	mutex_init(&ncp->lock);
+	i2c_set_clientdata(client, ncp);
+
+	ret = led_classdev_multicolor_register_ext(dev, &ncp->mc_dev, &init_data);
+	if (ret)
+		goto destroy_lock;
+
+	return 0;
+
+destroy_lock:
+	mutex_destroy(&ncp->lock);
+
+release_mc_node:
+	fwnode_handle_put(mc_node);
+
+	return ret;
+}
+
+static void ncp5623_remove(struct i2c_client *client)
+{
+	struct ncp5623 *ncp = i2c_get_clientdata(client);
+
+	mutex_lock(&ncp->lock);
+	ncp->delay = 0;
+	mutex_unlock(&ncp->lock);
+
+	ncp5623_write(client, NCP5623_DIMMING_TIME_REG, 0);
+	led_classdev_multicolor_unregister(&ncp->mc_dev);
+	mutex_destroy(&ncp->lock);
+}
+
+static void ncp5623_shutdown(struct i2c_client *client)
+{
+	struct ncp5623 *ncp = i2c_get_clientdata(client);
+
+	if (!(ncp->mc_dev.led_cdev.flags & LED_RETAIN_AT_SHUTDOWN))
+		ncp5623_write(client, NCP5623_SHUTDOWN_REG, 0);
+
+	mutex_destroy(&ncp->lock);
+}
+
+static const struct of_device_id ncp5623_id[] = {
+	{ .compatible = "onnn,ncp5623" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, ncp5623_id);
+
+static struct i2c_driver ncp5623_i2c_driver = {
+	.driver	= {
+		.name = "ncp5623",
+		.of_match_table = ncp5623_id,
+	},
+	.probe = ncp5623_probe,
+	.remove = ncp5623_remove,
+	.shutdown = ncp5623_shutdown,
+};
+
+module_i2c_driver(ncp5623_i2c_driver);
+
+MODULE_AUTHOR("Abdel Alkuor <alkuor@xxxxxxxxx>");
+MODULE_DESCRIPTION("NCP5623 Multi-LED driver");
+MODULE_LICENSE("GPL");
-- 
2.34.1