[PATCH v2 3/4] leds: Add LED support for MT6323 PMIC

[<sean.wang@mediatek.com>]

From: Sean Wang <sean.wang@mediatek.com>

MT6323 PMIC is a multi-function device that includes
LED function. It allows attaching upto 4 LEDs which can
either be on, off or dimmed and/or blinked with the the
controller.

Signed-off-by: Sean Wang <sean.wang@mediatek.com>
---
 drivers/leds/Kconfig       |   8 +
 drivers/leds/Makefile      |   1 +
 drivers/leds/leds-mt6323.c | 464 +++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 473 insertions(+)
 create mode 100644 drivers/leds/leds-mt6323.c

diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index c621cbb..30095fc 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -117,6 +117,14 @@ config LEDS_MIKROTIK_RB532
 	  This option enables support for the so called "User LED" of
 	  Mikrotik's Routerboard 532.
 
+config LEDS_MT6323
+	tristate "LED Support for Mediatek MT6323 PMIC"
+	depends on LEDS_CLASS
+	depends on MFD_MT6397
+	help
+	  This option enables support for on-chip LED drivers found on
+	  Mediatek MT6323 PMIC.
+
 config LEDS_S3C24XX
 	tristate "LED Support for Samsung S3C24XX GPIO LEDs"
 	depends on LEDS_CLASS
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index 6b82737..4feb332 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -72,6 +72,7 @@ obj-$(CONFIG_LEDS_IS31FL32XX)		+= leds-is31fl32xx.o
 obj-$(CONFIG_LEDS_PM8058)		+= leds-pm8058.o
 obj-$(CONFIG_LEDS_MLXCPLD)		+= leds-mlxcpld.o
 obj-$(CONFIG_LEDS_NIC78BX)		+= leds-nic78bx.o
+obj-$(CONFIG_LEDS_MT6323)		+= leds-mt6323.o
 
 # LED SPI Drivers
 obj-$(CONFIG_LEDS_DAC124S085)		+= leds-dac124s085.o
diff --git a/drivers/leds/leds-mt6323.c b/drivers/leds/leds-mt6323.c
new file mode 100644
index 0000000..f6eeb6c
--- /dev/null
+++ b/drivers/leds/leds-mt6323.c
@@ -0,0 +1,464 @@
+/*
+ * LED driver for Mediatek MT6323 PMIC
+ *
+ * Copyright (C) 2017 Sean Wang <sean.wang@mediatek.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+#include <linux/kernel.h>
+#include <linux/leds.h>
+#include <linux/mfd/mt6323/registers.h>
+#include <linux/mfd/mt6397/core.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+/*
+ * Register field for MT6323_TOP_CKPDN0 to enable
+ * 32K clock common for LED device
+ */
+#define MT6323_RG_DRV_32K_CK_PDN	BIT(11)
+#define MT6323_RG_DRV_32K_CK_PDN_MASK	BIT(11)
+
+/*
+ * Register field for MT6323_TOP_CKPDN2 to enable
+ * individual clock for LED device
+ */
+#define MT6323_RG_ISINK_CK_PDN(i)	BIT(i)
+#define MT6323_RG_ISINK_CK_PDN_MASK(i)	BIT(i)
+
+/*
+ * Register field for MT6323_TOP_CKCON1 to select
+ * clock source
+ */
+#define MT6323_RG_ISINK_CK_SEL_MASK(i)	(BIT(10) << (i))
+
+/*
+ * Register for MT6323_ISINK_CON0 to setup the
+ * duty cycle of the blink
+ */
+#define MT6323_ISINK_CON0(i)		(MT6323_ISINK0_CON0 + 0x8 * (i))
+#define MT6323_ISINK_DIM_DUTY_MASK	(0x1f << 8)
+#define MT6323_ISINK_DIM_DUTY(i)	(((i) << 8) & \
+					MT6323_ISINK_DIM_DUTY_MASK)
+
+/*
+ * Register to setup the period of the blink
+ */
+#define MT6323_ISINK_CON1(i)		(MT6323_ISINK0_CON1 + 0x8 * (i))
+#define MT6323_ISINK_DIM_FSEL_MASK	(0xffff)
+#define MT6323_ISINK_DIM_FSEL(i)	((i) & MT6323_ISINK_DIM_FSEL_MASK)
+
+/*
+ * Register to control the brightness
+ */
+#define MT6323_ISINK_CON2(i)		(MT6323_ISINK0_CON2 + 0x8 * (i))
+#define MT6323_ISINK_CH_STEP_SHIFT	12
+#define MT6323_ISINK_CH_STEP_MASK	(0x7 << 12)
+#define MT6323_ISINK_CH_STEP(i)		(((i) << 12) & \
+					MT6323_ISINK_CH_STEP_MASK)
+#define MT6323_ISINK_SFSTR0_TC_MASK	(0x3 << 1)
+#define MT6323_ISINK_SFSTR0_TC(i)	(((i) << 1) & \
+					MT6323_ISINK_SFSTR0_TC_MASK)
+#define MT6323_ISINK_SFSTR0_EN_MASK	BIT(0)
+#define MT6323_ISINK_SFSTR0_EN		BIT(0)
+
+/*
+ * Register to LED channel enablement
+ */
+#define MT6323_ISINK_CH_EN_MASK(i)	BIT(i)
+#define MT6323_ISINK_CH_EN(i)		BIT(i)
+
+#define MTK_MAX_PERIOD		      10000
+#define MTK_MAX_DEVICES			  4
+#define MTK_MAX_BRIGHTNESS		  6
+#define MTK_UNIT_DUTY		       3125
+
+struct mtk_leds;
+
+/**
+ * struct mtk_led - state container for the LED device
+ * @id: the identifier in MT6323 LED device
+ * @parent: the pointer to MT6323 LED controller
+ * @cdev: LED class device for this LED device
+ * @current_brightness: current state of the LED device
+ */
+struct mtk_led {
+	int    id;
+	struct mtk_leds *parent;
+	struct led_classdev cdev;
+	u8 current_brightness;
+};
+
+/**
+ * struct mtk_leds -	state container for holding LED controller
+ *			of the driver
+ * @dev:		The device pointer
+ * @hw:			The underlying hardware providing shared
+ *			bus for the register operations
+ * @led_num:		How much the LED device the controller could control
+ * @lock:		The lock among process context
+ * @led:		The array that contains the state of individual
+ *			LED device
+ */
+struct mtk_leds {
+	struct device	*dev;
+	struct mt6397_chip *hw;
+	u8     led_num;
+	/* protect among process context */
+	struct mutex	 lock;
+	struct mtk_led	 led[MTK_MAX_DEVICES];
+};
+
+static int mtk_led_hw_off(struct led_classdev *cdev)
+{
+	struct mtk_led *led = container_of(cdev, struct mtk_led, cdev);
+	struct mtk_leds *leds = led->parent;
+	struct regmap *regmap = leds->hw->regmap;
+	unsigned int status;
+	int ret;
+
+	status = MT6323_ISINK_CH_EN(led->id);
+	ret = regmap_update_bits(regmap, MT6323_ISINK_EN_CTRL,
+				 MT6323_ISINK_CH_EN_MASK(led->id), ~status);
+	if (ret < 0)
+		return ret;
+
+	usleep_range(100, 300);
+	ret = regmap_update_bits(regmap, MT6323_TOP_CKPDN2,
+				 MT6323_RG_ISINK_CK_PDN_MASK(led->id),
+				 MT6323_RG_ISINK_CK_PDN(led->id));
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+static int get_mtk_led_hw_brightness(struct led_classdev *cdev)
+{
+	struct mtk_led *led = container_of(cdev, struct mtk_led, cdev);
+	struct mtk_leds *leds = led->parent;
+	struct regmap *regmap = leds->hw->regmap;
+	unsigned int status;
+	int ret;
+
+	ret = regmap_read(regmap, MT6323_TOP_CKPDN2, &status);
+	if (ret < 0)
+		return ret;
+
+	if (status & MT6323_RG_ISINK_CK_PDN_MASK(led->id))
+		return 0;
+
+	ret = regmap_read(regmap, MT6323_ISINK_EN_CTRL, &status);
+	if (ret < 0)
+		return ret;
+
+	if (!(status & MT6323_ISINK_CH_EN(led->id)))
+		return 0;
+
+	ret = regmap_read(regmap, MT6323_ISINK_CON2(led->id), &status);
+	if (ret < 0)
+		return ret;
+
+	return  ((status & MT6323_ISINK_CH_STEP_MASK)
+		  >> MT6323_ISINK_CH_STEP_SHIFT) + 1;
+}
+
+static int mtk_led_hw_on(struct led_classdev *cdev)
+{
+	struct mtk_led *led = container_of(cdev, struct mtk_led, cdev);
+	struct mtk_leds *leds = led->parent;
+	struct regmap *regmap = leds->hw->regmap;
+	unsigned int status;
+	int ret;
+
+	/*
+	 * Setup required clock source, enable the corresponding
+	 * clock and channel and let work with continuous blink as
+	 * the default
+	 */
+	ret = regmap_update_bits(regmap, MT6323_TOP_CKCON1,
+				 MT6323_RG_ISINK_CK_SEL_MASK(led->id), 0);
+	if (ret < 0)
+		return ret;
+
+	status = MT6323_RG_ISINK_CK_PDN(led->id);
+	ret = regmap_update_bits(regmap, MT6323_TOP_CKPDN2,
+				 MT6323_RG_ISINK_CK_PDN_MASK(led->id),
+				 ~status);
+	if (ret < 0)
+		return ret;
+
+	usleep_range(100, 300);
+
+	ret = regmap_update_bits(regmap, MT6323_ISINK_EN_CTRL,
+				 MT6323_ISINK_CH_EN_MASK(led->id),
+				 MT6323_ISINK_CH_EN(led->id));
+	if (ret < 0)
+		return ret;
+
+	ret = regmap_update_bits(regmap, MT6323_ISINK_CON2(led->id),
+				 MT6323_ISINK_CH_STEP_MASK,
+				 MT6323_ISINK_CH_STEP(1));
+	if (ret < 0)
+		return ret;
+
+	ret = regmap_update_bits(regmap, MT6323_ISINK_CON0(led->id),
+				 MT6323_ISINK_DIM_DUTY_MASK,
+				 MT6323_ISINK_DIM_DUTY(31));
+	if (ret < 0)
+		return ret;
+
+	ret = regmap_update_bits(regmap, MT6323_ISINK_CON1(led->id),
+				 MT6323_ISINK_DIM_FSEL_MASK,
+				 MT6323_ISINK_DIM_FSEL(1000));
+	if (ret < 0)
+		return ret;
+
+	led->current_brightness = 1;
+
+	return 0;
+}
+
+static int mtk_led_set_blink(struct led_classdev *cdev,
+			     unsigned long *delay_on,
+			     unsigned long *delay_off)
+{
+	struct mtk_led *led = container_of(cdev, struct mtk_led, cdev);
+	struct mtk_leds *leds = led->parent;
+	struct regmap *regmap = leds->hw->regmap;
+	u16 period;
+	u8 duty_cycle, duty_hw;
+	int ret;
+
+	/*
+	 * Units are in ms , if over the hardware able
+	 * to support, fallback into software blink
+	 */
+	if (*delay_on + *delay_off > MTK_MAX_PERIOD)
+		return -EINVAL;
+
+	/*
+	 * LED subsystem requires a default user
+	 * friendly blink pattern for the LED so using
+	 * 1Hz duty cycle 50% here if without specific
+	 * value delay_on and delay off being assigned
+	 */
+	if (*delay_on == 0 && *delay_off == 0) {
+		*delay_on = 500;
+		*delay_off = 500;
+	}
+
+	period = *delay_on + *delay_off;
+
+	/*
+	 * duty_cycle is the percentage of period during
+	 * which the led is ON
+	 */
+	duty_cycle = 100 * (*delay_on) / period;
+
+	mutex_lock(&leds->lock);
+
+	if (!led->current_brightness) {
+		ret = mtk_led_hw_on(cdev);
+		if (ret < 0)
+			goto out;
+	}
+
+	duty_hw = DIV_ROUND_CLOSEST(duty_cycle * 1000, MTK_UNIT_DUTY);
+	ret = regmap_update_bits(regmap, MT6323_ISINK_CON0(led->id),
+				 MT6323_ISINK_DIM_DUTY_MASK,
+				 MT6323_ISINK_DIM_DUTY(duty_hw));
+	if (ret < 0)
+		goto out;
+
+	ret = regmap_update_bits(regmap, MT6323_ISINK_CON1(led->id),
+				 MT6323_ISINK_DIM_FSEL_MASK,
+				 MT6323_ISINK_DIM_FSEL(period - 1));
+out:
+	mutex_unlock(&leds->lock);
+
+	return ret;
+}
+
+static int mtk_led_set_brightness(struct led_classdev *cdev,
+				  enum led_brightness brightness)
+{
+	struct mtk_led *led = container_of(cdev, struct mtk_led, cdev);
+	struct mtk_leds *leds = led->parent;
+	struct regmap *regmap = leds->hw->regmap;
+	int ret;
+
+	mutex_lock(&leds->lock);
+
+	if (!led->current_brightness && brightness) {
+		ret = mtk_led_hw_on(cdev);
+		if (ret < 0)
+			goto out;
+	}
+
+	if (brightness) {
+		/*
+		 * Setup current output for the corresponding
+		 * brightness level
+		 */
+		ret = regmap_update_bits(regmap, MT6323_ISINK_CON2(led->id),
+					 MT6323_ISINK_CH_STEP_MASK,
+					 MT6323_ISINK_CH_STEP(brightness - 1));
+		if (ret < 0)
+			goto out;
+
+		ret = regmap_update_bits(regmap, MT6323_ISINK_CON2(led->id),
+					 MT6323_ISINK_SFSTR0_TC_MASK |
+					 MT6323_ISINK_SFSTR0_EN_MASK,
+					 MT6323_ISINK_SFSTR0_TC(2) |
+					 MT6323_ISINK_SFSTR0_EN);
+		if (ret < 0)
+			goto out;
+	} else {
+		ret = mtk_led_hw_off(cdev);
+		if (ret < 0)
+			goto out;
+	}
+
+	led->current_brightness = brightness;
+out:
+	mutex_unlock(&leds->lock);
+
+	return ret;
+}
+
+static int mt6323_led_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *np = pdev->dev.of_node;
+	struct device_node *child;
+	struct mt6397_chip *hw = dev_get_drvdata(pdev->dev.parent);
+	struct mtk_leds *leds;
+	int ret, i = 0, count;
+	const char *state;
+	unsigned int status;
+
+	count = of_get_child_count(np);
+	if (!count)
+		return -ENODEV;
+
+	/*
+	 * The number the LEDs on MT6323 could be support is
+	 * up to MTK_MAX_DEVICES
+	 */
+	count = (count <= MTK_MAX_DEVICES) ? count : MTK_MAX_DEVICES;
+
+	leds = devm_kzalloc(dev, sizeof(struct mtk_leds) +
+			    sizeof(struct mtk_led) * count,
+			    GFP_KERNEL);
+	if (!leds)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, leds);
+	leds->dev = dev;
+
+	/*
+	 * leds->hw points to the underlying bus for the register
+	 * controlled
+	 */
+	leds->hw = hw;
+	mutex_init(&leds->lock);
+	leds->led_num = count;
+
+	status = MT6323_RG_DRV_32K_CK_PDN;
+	ret = regmap_update_bits(leds->hw->regmap, MT6323_TOP_CKPDN0,
+				 MT6323_RG_DRV_32K_CK_PDN_MASK, ~status);
+	if (ret < 0) {
+		dev_err(leds->dev,
+			"Failed to update MT6323_TOP_CKPDN0 Register\n");
+		return ret;
+	}
+
+	for_each_available_child_of_node(np, child) {
+		leds->led[i].cdev.name =
+			of_get_property(child, "label", NULL) ? :
+					child->name;
+		leds->led[i].cdev.default_trigger = of_get_property(child,
+						    "linux,default-trigger",
+						    NULL);
+		leds->led[i].cdev.max_brightness = MTK_MAX_BRIGHTNESS;
+		leds->led[i].cdev.brightness_set_blocking =
+					mtk_led_set_brightness;
+		leds->led[i].cdev.blink_set = mtk_led_set_blink;
+		leds->led[i].id = i;
+		leds->led[i].parent = leds;
+		state = of_get_property(child, "default-state", NULL);
+		if (state) {
+			if (!strcmp(state, "keep")) {
+				leds->led[i].current_brightness =
+				get_mtk_led_hw_brightness(&leds->led[i].cdev);
+			} else if (!strcmp(state, "on")) {
+				mtk_led_set_brightness(&leds->led[i].cdev, 1);
+			} else  {
+				mtk_led_set_brightness(&leds->led[i].cdev,
+						       0);
+			}
+		}
+		ret = devm_led_classdev_register(dev, &leds->led[i].cdev);
+		if (ret) {
+			dev_err(&pdev->dev, "Failed to register LED: %d\n",
+				ret);
+			return ret;
+		}
+		leds->led[i].cdev.dev->of_node = child;
+		i++;
+	}
+
+	return 0;
+}
+
+static int mt6323_led_remove(struct platform_device *pdev)
+{
+	struct mtk_leds *leds = platform_get_drvdata(pdev);
+	int i;
+
+	/*
+	 * Turned the LED to OFF state on driver removal
+	 */
+	for (i = 0 ; i < leds->led_num ; i++)
+		mtk_led_hw_off(&leds->led[i].cdev);
+
+	regmap_update_bits(leds->hw->regmap, MT6323_TOP_CKPDN0,
+			   MT6323_RG_DRV_32K_CK_PDN_MASK,
+			   MT6323_RG_DRV_32K_CK_PDN);
+
+	mutex_destroy(&leds->lock);
+
+	return 0;
+}
+
+static const struct of_device_id mt6323_led_dt_match[] = {
+	{ .compatible = "mediatek,mt6323-led" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, mt6323_led_dt_match);
+
+static struct platform_driver mt6323_led_driver = {
+	.probe		= mt6323_led_probe,
+	.remove		= mt6323_led_remove,
+	.driver		= {
+		.name	= "mt6323-led",
+		.of_match_table = mt6323_led_dt_match,
+	},
+};
+
+module_platform_driver(mt6323_led_driver);
+
+MODULE_DESCRIPTION("LED driver for Mediatek MT6323 PMIC");
+MODULE_AUTHOR("Sean Wang <sean.wang@mediatek.com>");
+MODULE_LICENSE("GPL");
-- 
1.9.1