[PATCH v2 2/2] leds: add Panasonic AN30259A support

[Simon Shields <simon@lineageos.org>]

AN30259A is a 3-channel LED driver which uses I2C. It supports timed
operation via an internal PWM clock, and variable brightness. This
driver offers support for basic hardware-based blinking and brightness
control.

The datasheet is freely available:
https://www.alliedelec.com/m/d/a9d2b3ee87c2d1a535a41dd747b1c247.pdf

Signed-off-by: Simon Shields <simon@lineageos.org>
---
 drivers/leds/Kconfig         |  11 ++
 drivers/leds/Makefile        |   1 +
 drivers/leds/leds-an30259a.c | 382 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 394 insertions(+)
 create mode 100644 drivers/leds/leds-an30259a.c

diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index 3e763d2a0cb3..369bfb1227f8 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -57,6 +57,17 @@ config LEDS_AAT1290
 	depends on PINCTRL
 	help
 	 This option enables support for the LEDs on the AAT1290.
+
+config LEDS_AN30259A
+	tristate "LED support for Panasonic AN30259A"
+	depends on LEDS_CLASS && I2C && OF
+	help
+	  This option enables support for the AN30259A 3-channel
+	  LED driver.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called leds-an30259a.
+
 config LEDS_APU
 	tristate "Front panel LED support for PC Engines APU/APU2 boards"
 	depends on LEDS_CLASS
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index 987884a5b9a5..44f9b42d1600 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -11,6 +11,7 @@ obj-$(CONFIG_LEDS_88PM860X)		+= leds-88pm860x.o
 obj-$(CONFIG_LEDS_AAT1290)		+= leds-aat1290.o
 obj-$(CONFIG_LEDS_APU)			+= leds-apu.o
 obj-$(CONFIG_LEDS_AS3645A)		+= leds-as3645a.o
+obj-$(CONFIG_LEDS_AN30259A)		+= leds-an30259a.o
 obj-$(CONFIG_LEDS_BCM6328)		+= leds-bcm6328.o
 obj-$(CONFIG_LEDS_BCM6358)		+= leds-bcm6358.o
 obj-$(CONFIG_LEDS_BD2802)		+= leds-bd2802.o
diff --git a/drivers/leds/leds-an30259a.c b/drivers/leds/leds-an30259a.c
new file mode 100644
index 000000000000..6170aa2e3adb
--- /dev/null
+++ b/drivers/leds/leds-an30259a.c
@@ -0,0 +1,382 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Driver for Panasonic AN30259A 3-channel LED driver
+ *
+ * Copyright (c) 2018 Simon Shields <simon@lineageos.org>
+ *
+ * Datasheet:
+ * https://www.alliedelec.com/m/d/a9d2b3ee87c2d1a535a41dd747b1c247.pdf
+ */
+#include <linux/i2c.h>
+#include <linux/leds.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/regmap.h>
+
+#define MAX_LEDS 3
+
+#define REG_SRESET 0x00
+#define LED_SRESET BIT(0)
+
+/* LED power registers */
+#define REG_LEDON 0x01
+#define LED_EN(x) BIT(x - 1)
+#define LED_SLOPE(x) BIT((x - 1) + 4)
+
+#define REG_LEDCC(x) (0x03 + (x - 1))
+
+/* slope control registers */
+#define REG_SLOPE(x) (0x06 + (x - 1))
+#define LED_SLOPETIME1(x) (x)
+#define LED_SLOPETIME2(x) ((x) << 4)
+
+#define REG_LEDCNT1(x) (0x09 + (4 * (x - 1)))
+#define LED_DUTYMAX(x) ((x) << 4)
+#define LED_DUTYMID(x) (x)
+
+#define REG_LEDCNT2(x) (0x0A + (4 * (x - 1)))
+#define LED_DELAY(x) ((x) << 4)
+#define LED_DUTYMIN(x) (x)
+
+/* detention time control (length of each slope step) */
+#define REG_LEDCNT3(x) (0x0B + (4 * (x - 1)))
+#define LED_DT1(x) (x)
+#define LED_DT2(x) ((x) << 4)
+
+#define REG_LEDCNT4(x) (0x0C + (4 * (x - 1)))
+#define LED_DT3(x) (x)
+#define LED_DT4(x) ((x) << 4)
+
+#define REG_MAX 0x14
+
+#define BLINK_MAX_TIME 7500 /* ms */
+#define SLOPE_RESOLUTION 500 /* ms */
+
+#define STATE_OFF 0
+#define STATE_KEEP 1
+#define STATE_ON 2
+
+struct an30259a;
+
+struct an30259a_led {
+	struct an30259a *chip;
+	struct led_classdev cdev;
+	u32 num;
+	u32 default_state;
+};
+
+struct an30259a {
+	struct mutex mutex; /* held when writing to registers */
+	struct i2c_client *client;
+	struct an30259a_led leds[MAX_LEDS];
+	struct regmap *regmap;
+	int num_leds;
+};
+
+static u8 an30259a_get_dutymax(u8 brightness)
+{
+	u8 duty_max, floor, ceil;
+
+	/* squash 8 bit number into 7-bit PWM range */
+	duty_max = brightness >> 1;
+
+	/* bottom 3 bits are always set for DUTYMAX
+	 * figure out the closest value
+	 */
+	ceil = duty_max | 0x7;
+	floor = ceil - 0x8;
+
+	if ((duty_max - floor) < (ceil - duty_max))
+		duty_max = floor >> 3;
+	else
+		duty_max = ceil >> 3;
+
+	return duty_max;
+}
+
+static int an30259a_brightness(struct an30259a_led *led,
+			       enum led_brightness brightness)
+{
+	int ret;
+	unsigned int ledon;
+	u8 dutymax;
+
+	ret = regmap_read(led->chip->regmap, REG_LEDON, &ledon);
+	if (ret)
+		return ret;
+
+	switch (brightness) {
+	case LED_OFF:
+		ledon &= ~LED_EN(led->num);
+		ledon &= ~LED_SLOPE(led->num);
+		break;
+	default:
+		ledon |= LED_EN(led->num);
+		dutymax = an30259a_get_dutymax(brightness & 0xff);
+		ret = regmap_write(led->chip->regmap, REG_LEDCNT1(led->num),
+				   LED_DUTYMAX(dutymax) | LED_DUTYMID(dutymax));
+		if (ret)
+			return ret;
+		break;
+	}
+	ret = regmap_write(led->chip->regmap, REG_LEDON, ledon);
+	if (ret)
+		return ret;
+
+	ret = regmap_write(led->chip->regmap, REG_LEDCC(led->num),
+			   brightness & 0xff);
+	if (ret)
+		return ret;
+
+	return ret;
+}
+
+static int an30259a_blink(struct an30259a_led *led,
+			  unsigned long *poff, unsigned long *pon)
+{
+	int ret, num = led->num;
+	unsigned int ledon;
+	unsigned long off = *poff, on = *pon;
+
+	/* slope time - multiples of 500ms only, floored */
+	off -= off % SLOPE_RESOLUTION;
+	/* don't floor off time to zero if a non-zero time was requested */
+	if (!off && *poff)
+		off += SLOPE_RESOLUTION;
+	else if (off > BLINK_MAX_TIME)
+		off = BLINK_MAX_TIME;
+	*poff = off;
+
+	on -= on % SLOPE_RESOLUTION;
+	/* don't floor on time to zero if a non-zero time was requested */
+	if (!on && *pon)
+		on += SLOPE_RESOLUTION;
+	else if (on > BLINK_MAX_TIME)
+		on = BLINK_MAX_TIME;
+	*pon = on;
+
+	/* convert into values the HW will understand */
+	off /= SLOPE_RESOLUTION;
+	on /= SLOPE_RESOLUTION;
+
+	/* duty min should be zero (=off), delay should be zero */
+	ret = regmap_write(led->chip->regmap, REG_LEDCNT2(num),
+			   LED_DELAY(0) | LED_DUTYMIN(0));
+	if (ret)
+		return ret;
+
+	/* reset detention time (no "breathing" effect) */
+	ret = regmap_write(led->chip->regmap, REG_LEDCNT3(num),
+			   LED_DT1(0) | LED_DT2(0));
+	if (ret)
+		return ret;
+	ret = regmap_write(led->chip->regmap, REG_LEDCNT4(num),
+			   LED_DT3(0) | LED_DT4(0));
+	if (ret)
+		return ret;
+
+	/* slope time controls on/off cycle length */
+	ret = regmap_write(led->chip->regmap, REG_SLOPE(num),
+			   LED_SLOPETIME1(off) | LED_SLOPETIME2(on));
+	if (ret)
+		return ret;
+
+	/* Finally, enable slope mode. */
+	ret = regmap_read(led->chip->regmap, REG_LEDON, &ledon);
+	if (ret)
+		return ret;
+
+	ledon |= LED_SLOPE(num);
+
+	return regmap_write(led->chip->regmap, REG_LEDON, ledon);
+}
+
+static int an30259a_led_set(struct led_classdev *cdev,
+			    enum led_brightness value)
+{
+	struct an30259a_led *led;
+	int ret;
+
+	led = container_of(cdev, struct an30259a_led, cdev);
+
+	mutex_lock(&led->chip->mutex);
+	ret = an30259a_brightness(led, value);
+	mutex_unlock(&led->chip->mutex);
+
+	return ret;
+}
+
+static int an30259a_blink_set(struct led_classdev *cdev,
+			      unsigned long *delay_off, unsigned long *delay_on)
+{
+	struct an30259a_led *led;
+	int ret;
+
+	led = container_of(cdev, struct an30259a_led, cdev);
+
+	mutex_lock(&led->chip->mutex);
+	ret = an30259a_blink(led, delay_off, delay_on);
+	mutex_unlock(&led->chip->mutex);
+
+	return ret;
+}
+
+static int an30259a_dt_init(struct i2c_client *client, struct an30259a *chip)
+{
+	struct device_node *np = client->dev.of_node, *child;
+	int count, ret;
+	int i = 0;
+	const char *str;
+
+	count = of_get_child_count(np);
+	if (!count || count > MAX_LEDS)
+		return -EINVAL;
+
+	for_each_child_of_node(np, child) {
+		u32 source;
+
+		ret = of_property_read_u32(child, "reg", &source);
+		if (ret != 0 || !source || source > MAX_LEDS) {
+			count--;
+			continue;
+		}
+
+		chip->leds[i].num = source;
+		chip->leds[i].chip = chip;
+
+		if (of_property_read_string(child, "label",
+					    &chip->leds[i].cdev.name))
+			chip->leds[i].cdev.name = "an30259a::";
+
+		if (!of_property_read_string(child, "default-state",
+					     &str)) {
+			if (!strcmp(str, "on"))
+				chip->leds[i].default_state = STATE_ON;
+			else if (!strcmp(str, "keep"))
+				chip->leds[i].default_state = STATE_KEEP;
+			else
+				chip->leds[i].default_state = STATE_OFF;
+		}
+
+		of_property_read_string(child, "linux,default-trigger",
+					&chip->leds[i].cdev.default_trigger);
+
+		i++;
+	}
+
+	if (!count)
+		return -EINVAL;
+
+	chip->num_leds = i;
+
+	return 0;
+}
+
+static const struct regmap_config an30259a_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.max_register = REG_MAX,
+};
+
+static void an30259a_init_default_state(struct an30259a_led *led)
+{
+	struct an30259a *chip = led->chip;
+	int ledon, err;
+
+	switch (led->default_state) {
+	case STATE_ON:
+		led->cdev.brightness = LED_FULL;
+		break;
+	case STATE_KEEP:
+		err = regmap_read(chip->regmap, REG_LEDON, &ledon);
+		if (err)
+			break;
+
+		if (!(ledon & LED_EN(led->num))) {
+			led->cdev.brightness = LED_OFF;
+			break;
+		}
+		regmap_read(chip->regmap, REG_LEDCC(led->num),
+			    &led->cdev.brightness);
+		break;
+	default:
+		led->cdev.brightness = LED_OFF;
+	}
+
+	an30259a_led_set(&led->cdev, led->cdev.brightness);
+}
+
+static int an30259a_probe(struct i2c_client *client)
+{
+	struct an30259a *chip;
+	int i, err;
+
+	chip = devm_kzalloc(&client->dev, sizeof(*chip), GFP_KERNEL);
+	if (!chip)
+		return -ENOMEM;
+
+	err = an30259a_dt_init(client, chip);
+	if (err < 0)
+		return err;
+
+	mutex_init(&chip->mutex);
+	chip->client = client;
+	i2c_set_clientdata(client, chip);
+
+	chip->regmap = devm_regmap_init_i2c(client, &an30259a_regmap_config);
+
+	for (i = 0; i < chip->num_leds; i++) {
+		an30259a_init_default_state(&chip->leds[i]);
+		chip->leds[i].cdev.brightness_set_blocking = an30259a_led_set;
+		chip->leds[i].cdev.blink_set = an30259a_blink_set;
+
+		err = devm_led_classdev_register(&client->dev,
+						 &chip->leds[i].cdev);
+		if (err < 0)
+			goto exit;
+	}
+	return 0;
+
+exit:
+	mutex_destroy(&chip->mutex);
+	return err;
+}
+
+static int an30259a_remove(struct i2c_client *client)
+{
+	struct an30259a *chip = i2c_get_clientdata(client);
+
+	mutex_destroy(&chip->mutex);
+
+	return 0;
+}
+
+static const struct of_device_id an30259a_match_table[] = {
+	{ .compatible = "panasonic,an30259a", },
+	{ /* sentinel */ },
+};
+
+MODULE_DEVICE_TABLE(of, an30259a_match_table);
+
+static const struct i2c_device_id an30259a_id[] = {
+	{ "an30259a", NULL },
+	{ /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(i2c, an30259a_id);
+
+static struct i2c_driver an30259a_driver = {
+	.driver = {
+		.name = "leds-an32059a",
+		.of_match_table = of_match_ptr(an30259a_match_table),
+	},
+	.probe_new = an30259a_probe,
+	.remove = an30259a_remove,
+	.id_table = an30259a_id,
+};
+
+module_i2c_driver(an30259a_driver);
+
+MODULE_AUTHOR("Simon Shields <simon@lineageos.org>");
+MODULE_DESCRIPTION("AN32059A LED driver");
+MODULE_LICENSE("GPL v2");
-- 
2.16.2