[PATCH 2/2] leds: Add Spreadtrum SC27xx breathing light controller driver

[Baolin Wang <baolin.wang@linaro.org>]

From: Xiaotong Lu <xiaotong.lu@spreadtrum.com>

This patch adds Spreadtrum SC27xx PMIC series breathing light controller
driver, which can support 3 LEDs. Each LED can work at normal PWM mode
and breathing mode.

Signed-off-by: Xiaotong Lu <xiaotong.lu@spreadtrum.com>
Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
---
 drivers/leds/Kconfig            |   11 ++
 drivers/leds/Makefile           |    1 +
 drivers/leds/leds-sc27xx-bltc.c |  369 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 381 insertions(+)
 create mode 100644 drivers/leds/leds-sc27xx-bltc.c

diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index 2c896c0..319449b 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -647,6 +647,17 @@ config LEDS_IS31FL32XX
 	  LED controllers. They are I2C devices with multiple constant-current
 	  channels, each with independent 256-level PWM control.
 
+config LEDS_SC27XX_BLTC
+	tristate "LED support for the SC27xx breathing light controller"
+	depends on LEDS_CLASS && MFD_SC27XX_PMIC
+	depends on OF
+	help
+	  Say Y here to include support for the SC27xx breathing light controller
+	  LEDs.
+
+	  This driver can also be built as a module. If so the module will be
+	  called leds-sc27xx-bltc.
+
 comment "LED driver for blink(1) USB RGB LED is under Special HID drivers (HID_THINGM)"
 
 config LEDS_BLINKM
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index 91eca81..ff6917e 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -76,6 +76,7 @@ obj-$(CONFIG_LEDS_MLXREG)		+= leds-mlxreg.o
 obj-$(CONFIG_LEDS_NIC78BX)		+= leds-nic78bx.o
 obj-$(CONFIG_LEDS_MT6323)		+= leds-mt6323.o
 obj-$(CONFIG_LEDS_LM3692X)		+= leds-lm3692x.o
+obj-$(CONFIG_LEDS_SC27XX_BLTC)		+= leds-sc27xx-bltc.o
 
 # LED SPI Drivers
 obj-$(CONFIG_LEDS_DAC124S085)		+= leds-dac124s085.o
diff --git a/drivers/leds/leds-sc27xx-bltc.c b/drivers/leds/leds-sc27xx-bltc.c
new file mode 100644
index 0000000..0016a87
--- /dev/null
+++ b/drivers/leds/leds-sc27xx-bltc.c
@@ -0,0 +1,369 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2018 Spreadtrum Communications Inc.
+ */
+
+#include <linux/leds.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+/* PMIC global control register definition */
+#define SC27XX_MODULE_EN0	0xc08
+#define SC27XX_CLK_EN0		0xc18
+#define SC27XX_RGB_CTRL		0xebc
+
+#define SC27XX_BLTC_EN		BIT(9)
+#define SC27XX_RTC_EN		BIT(7)
+#define SC27XX_RGB_PD		BIT(0)
+
+/* Breathing light controller register definition */
+#define SC27XX_LEDS_CTRL	0x00
+#define SC27XX_LEDS_PRESCALE	0x04
+#define SC27XX_LEDS_DUTY	0x08
+#define SC27XX_LEDS_CURVE0	0x0c
+#define SC27XX_LEDS_CURVE1	0x10
+
+#define SC27XX_CTRL_SHIFT	4
+#define SC27XX_LED_RUN		BIT(0)
+#define SC27XX_LED_TYPE		BIT(1)
+
+#define SC27XX_DUTY_SHIFT	8
+#define SC27XX_DUTY_MASK	GENMASK(15, 0)
+#define SC27XX_MOD_MASK		GENMASK(7, 0)
+
+#define SC27XX_CURVE_SHIFT	8
+#define SC27XX_CURVE_L_MASK	GENMASK(7, 0)
+#define SC27XX_CURVE_H_MASK	GENMASK(15, 8)
+
+#define SC27XX_LEDS_OFFSET	0x10
+#define SC27XX_LEDS_MAX		3
+
+/*
+ * The SC27xx breathing light controller can support 3 outputs: red LED,
+ * green LED and blue LED. Each LED can support normal PWM mode and breathing
+ * mode.
+ *
+ * In breathing mode, the LED output curve includes raise, high, fall and low 4
+ * stages, and the duration of each stage is configurable.
+ */
+enum sc27xx_led_config {
+	SC27XX_RAISE_TIME,
+	SC27XX_FALL_TIME,
+	SC27XX_HIGH_TIME,
+	SC27XX_LOW_TIME,
+};
+
+struct sc27xx_led {
+	struct led_classdev ldev;
+	struct sc27xx_led_priv *priv;
+	enum led_brightness value;
+	u8 line;
+	bool breath_mode;
+	bool active;
+};
+
+struct sc27xx_led_priv {
+	struct sc27xx_led leds[SC27XX_LEDS_MAX];
+	struct regmap *regmap;
+	u32 base;
+};
+
+#define to_sc27xx_led(ldev) \
+	container_of(ldev, struct sc27xx_led, ldev)
+
+static int sc27xx_led_init(struct regmap *regmap)
+{
+	int err;
+
+	err = regmap_update_bits(regmap, SC27XX_MODULE_EN0, SC27XX_BLTC_EN,
+				 SC27XX_BLTC_EN);
+	if (err)
+		return err;
+
+	err = regmap_update_bits(regmap, SC27XX_CLK_EN0, SC27XX_RTC_EN,
+				 SC27XX_RTC_EN);
+	if (err)
+		return err;
+
+	return regmap_update_bits(regmap, SC27XX_RGB_CTRL, SC27XX_RGB_PD, 0);
+}
+
+static u32 sc27xx_led_get_offset(struct sc27xx_led *leds)
+{
+	return leds->priv->base + SC27XX_LEDS_OFFSET * leds->line;
+}
+
+static int sc27xx_led_enable(struct sc27xx_led *leds)
+{
+	u32 base = sc27xx_led_get_offset(leds);
+	u32 ctrl_base = leds->priv->base + SC27XX_LEDS_CTRL;
+	u8 ctrl_shift = SC27XX_CTRL_SHIFT * leds->line;
+	struct regmap *regmap = leds->priv->regmap;
+	int err;
+
+	err = regmap_update_bits(regmap, base + SC27XX_LEDS_DUTY,
+				 SC27XX_DUTY_MASK,
+				 (leds->value  << SC27XX_DUTY_SHIFT) |
+				 SC27XX_MOD_MASK);
+	if (err)
+		return err;
+
+	if (leds->breath_mode)
+		return regmap_update_bits(regmap, ctrl_base,
+					  SC27XX_LED_RUN << ctrl_shift,
+					  SC27XX_LED_RUN << ctrl_shift);
+
+	return regmap_update_bits(regmap, ctrl_base,
+			(SC27XX_LED_RUN | SC27XX_LED_TYPE) << ctrl_shift,
+			(SC27XX_LED_RUN | SC27XX_LED_TYPE) << ctrl_shift);
+}
+
+static int sc27xx_led_disable(struct sc27xx_led *leds)
+{
+	u8 ctrl_shift = SC27XX_CTRL_SHIFT * leds->line;
+
+	leds->breath_mode = false;
+
+	return regmap_update_bits(leds->priv->regmap,
+			leds->priv->base + SC27XX_LEDS_CTRL,
+			(SC27XX_LED_RUN | SC27XX_LED_TYPE) << ctrl_shift, 0);
+}
+
+static int sc27xx_led_set(struct led_classdev *ldev, enum led_brightness value)
+{
+	struct sc27xx_led *leds = to_sc27xx_led(ldev);
+
+	leds->value = value;
+	if (value == LED_OFF)
+		return sc27xx_led_disable(leds);
+
+	return sc27xx_led_enable(leds);
+}
+
+static int sc27xx_led_config(struct sc27xx_led *leds,
+			     enum sc27xx_led_config config, u32 val)
+{
+	u32 base = sc27xx_led_get_offset(leds);
+	struct regmap *regmap = leds->priv->regmap;
+	int err;
+
+	switch (config) {
+	case SC27XX_RAISE_TIME:
+		err = regmap_update_bits(regmap, base + SC27XX_LEDS_CURVE0,
+					 SC27XX_CURVE_L_MASK, val);
+		break;
+	case SC27XX_FALL_TIME:
+		err = regmap_update_bits(regmap, base + SC27XX_LEDS_CURVE0,
+					 SC27XX_CURVE_H_MASK,
+					 val << SC27XX_CURVE_SHIFT);
+		break;
+	case SC27XX_HIGH_TIME:
+		err = regmap_update_bits(regmap, base + SC27XX_LEDS_CURVE1,
+					 SC27XX_CURVE_L_MASK, val);
+		break;
+	case SC27XX_LOW_TIME:
+		err = regmap_update_bits(regmap, base + SC27XX_LEDS_CURVE1,
+					 SC27XX_CURVE_H_MASK,
+					 val << SC27XX_CURVE_SHIFT);
+		break;
+	default:
+		err = -ENOTSUPP;
+		break;
+	}
+
+	if (!err && !leds->breath_mode)
+		leds->breath_mode = true;
+
+	return err;
+}
+
+static ssize_t raise_time_store(struct device *dev,
+				struct device_attribute *attr,
+				const char *buf, size_t size)
+{
+	struct led_classdev *ldev = dev_get_drvdata(dev);
+	struct sc27xx_led *leds = to_sc27xx_led(ldev);
+	u32 val;
+	int err;
+
+	if (kstrtou32(buf, 10, &val))
+		return -EINVAL;
+
+	err = sc27xx_led_config(leds, SC27XX_RAISE_TIME, val);
+	if (err)
+		return err;
+
+	return size;
+}
+
+static ssize_t fall_time_store(struct device *dev,
+			       struct device_attribute *attr,
+			       const char *buf, size_t size)
+{
+	struct led_classdev *ldev = dev_get_drvdata(dev);
+	struct sc27xx_led *leds = to_sc27xx_led(ldev);
+	u32 val;
+	int err;
+
+	if (kstrtou32(buf, 10, &val))
+		return -EINVAL;
+
+	err = sc27xx_led_config(leds, SC27XX_FALL_TIME, val);
+	if (err)
+		return err;
+
+	return size;
+}
+
+static ssize_t high_time_store(struct device *dev,
+			       struct device_attribute *attr,
+			       const char *buf, size_t size)
+{
+	struct led_classdev *ldev = dev_get_drvdata(dev);
+	struct sc27xx_led *leds = to_sc27xx_led(ldev);
+	u32 val;
+	int err;
+
+	if (kstrtou32(buf, 10, &val))
+		return -EINVAL;
+
+	err = sc27xx_led_config(leds, SC27XX_HIGH_TIME, val);
+	if (err)
+		return err;
+
+	return size;
+}
+
+static ssize_t low_time_store(struct device *dev,
+			      struct device_attribute *attr,
+			      const char *buf, size_t size)
+{
+	struct led_classdev *ldev = dev_get_drvdata(dev);
+	struct sc27xx_led *leds = to_sc27xx_led(ldev);
+	u32 val;
+	int err;
+
+	if (kstrtou32(buf, 10, &val))
+		return -EINVAL;
+
+	err = sc27xx_led_config(leds, SC27XX_LOW_TIME, val);
+	if (err)
+		return err;
+
+	return size;
+}
+
+static DEVICE_ATTR_WO(raise_time);
+static DEVICE_ATTR_WO(fall_time);
+static DEVICE_ATTR_WO(high_time);
+static DEVICE_ATTR_WO(low_time);
+
+static struct attribute *sc27xx_led_attrs[] = {
+	&dev_attr_raise_time.attr,
+	&dev_attr_fall_time.attr,
+	&dev_attr_high_time.attr,
+	&dev_attr_low_time.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(sc27xx_led);
+
+static int sc27xx_led_register(struct device *dev, struct sc27xx_led_priv *priv)
+{
+	int i, err;
+
+	err = sc27xx_led_init(priv->regmap);
+	if (err)
+		return err;
+
+	for (i = 0; i < SC27XX_LEDS_MAX; i++) {
+		struct sc27xx_led *led = &priv->leds[i];
+
+		if (!led->active)
+			continue;
+
+		led->line = i;
+		led->priv = priv;
+		led->ldev.brightness_set_blocking = sc27xx_led_set;
+		led->ldev.max_brightness = LED_FULL;
+		led->ldev.groups = sc27xx_led_groups;
+
+		err = devm_led_classdev_register(dev, &led->ldev);
+		if (err)
+			return err;
+	}
+
+	return 0;
+}
+
+static int sc27xx_led_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *np = dev->of_node, *child;
+	struct sc27xx_led_priv *priv;
+	u32 base, count, reg;
+	int err;
+
+	count = of_get_child_count(np);
+	if (!count || count > SC27XX_LEDS_MAX)
+		return -EINVAL;
+
+	err = of_property_read_u32(np, "reg", &base);
+	if (err) {
+		dev_err(dev, "fail to get reg of property\n");
+		return err;
+	}
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->base = base;
+	priv->regmap = dev_get_regmap(dev->parent, NULL);
+	if (IS_ERR(priv->regmap)) {
+		err = PTR_ERR(priv->regmap);
+		dev_err(dev, "failed to get regmap: %d\n", err);
+		return err;
+	}
+
+	for_each_child_of_node(np, child) {
+		err = of_property_read_u32(child, "reg", &reg);
+		if (err) {
+			of_node_put(child);
+			return err;
+		}
+
+		if (reg < 0 || reg >= SC27XX_LEDS_MAX
+		    || priv->leds[reg].active) {
+			of_node_put(child);
+			return -EINVAL;
+		}
+
+		priv->leds[reg].active = true;
+		priv->leds[reg].ldev.name =
+			of_get_property(child, "label", NULL) ? : child->name;
+	}
+
+	return sc27xx_led_register(dev, priv);
+}
+
+static const struct of_device_id sc27xx_led_of_match[] = {
+	{ .compatible = "sprd,sc27xx-bltc", },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, sc27xx_led_of_match);
+
+static struct platform_driver sc27xx_led_driver = {
+	.driver = {
+		.name = "sc27xx-bltc",
+		.of_match_table = sc27xx_led_of_match,
+	},
+	.probe = sc27xx_led_probe,
+};
+
+module_platform_driver(sc27xx_led_driver);
+
+MODULE_DESCRIPTION("Spreadtrum SC27xx breathing light controller driver");
+MODULE_AUTHOR("Xiaotong Lu <xiaotong.lu@spreadtrum.com>");
+MODULE_LICENSE("GPL v2");
-- 
1.7.9.5