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

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

Signed-off-by: Sean Wang <sean.w...@mediatek.com>
---
 drivers/leds/Kconfig       |   8 +
 drivers/leds/Makefile      |   1 +
 drivers/leds/leds-mt6323.c | 502 +++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 511 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..48081bc
--- /dev/null
+++ b/drivers/leds/leds-mt6323.c
@@ -0,0 +1,502 @@
+/*
+ * LED driver for Mediatek MT6323 PMIC
+ *
+ * Copyright (C) 2017 Sean Wang <sean.w...@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 MT6323_MAX_PERIOD              10000
+#define MT6323_MAX_LEDS                        4
+#define MT6323_MAX_BRIGHTNESS          6
+#define MT6323_UNIT_DUTY               3125
+#define MT6323_CAL_HW_DUTY(o, p)       DIV_ROUND_CLOSEST((o) * 100000ul,\
+                                       (p) * MT6323_UNIT_DUTY)
+
+struct mt6323_leds;
+
+/**
+ * struct mt6323_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 mt6323_led {
+       int                     id;
+       struct mt6323_leds      *parent;
+       struct led_classdev     cdev;
+       enum led_brightness     current_brightness;
+};
+
+/**
+ * struct mt6323_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
+ * @lock:              the lock among process context
+ * @led:               the array that contains the state of individual
+ *                     LED device
+ */
+struct mt6323_leds {
+       struct device           *dev;
+       struct mt6397_chip      *hw;
+       /* protect among process context */
+       struct mutex            lock;
+       struct mt6323_led       *led[MT6323_MAX_LEDS];
+};
+
+static int mt6323_led_hw_brightness(struct led_classdev *cdev,
+                                   enum led_brightness brightness)
+{
+       struct mt6323_led *led = container_of(cdev, struct mt6323_led, cdev);
+       struct mt6323_leds *leds = led->parent;
+       struct regmap *regmap = leds->hw->regmap;
+       u32 con2_mask = 0, con2_val = 0;
+       int ret;
+
+       /*
+        * Setup current output for the corresponding
+        * brightness level.
+        */
+       con2_mask |= MT6323_ISINK_CH_STEP_MASK |
+                    MT6323_ISINK_SFSTR0_TC_MASK |
+                    MT6323_ISINK_SFSTR0_EN_MASK;
+       con2_val |=  MT6323_ISINK_CH_STEP(brightness - 1) |
+                    MT6323_ISINK_SFSTR0_TC(2) |
+                    MT6323_ISINK_SFSTR0_EN;
+
+       ret = regmap_update_bits(regmap, MT6323_ISINK_CON2(led->id),
+                                con2_mask, con2_val);
+       return ret;
+}
+
+static int mt6323_led_hw_off(struct led_classdev *cdev)
+{
+       struct mt6323_led *led = container_of(cdev, struct mt6323_led, cdev);
+       struct mt6323_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 enum led_brightness
+mt6323_get_led_hw_brightness(struct led_classdev *cdev)
+{
+       struct mt6323_led *led = container_of(cdev, struct mt6323_led, cdev);
+       struct mt6323_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 mt6323_led_hw_on(struct led_classdev *cdev,
+                           enum led_brightness brightness)
+{
+       struct mt6323_led *led = container_of(cdev, struct mt6323_led, cdev);
+       struct mt6323_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 = mt6323_led_hw_brightness(cdev, brightness);
+       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;
+
+       return 0;
+}
+
+static int mt6323_led_set_blink(struct led_classdev *cdev,
+                               unsigned long *delay_on,
+                               unsigned long *delay_off)
+{
+       struct mt6323_led *led = container_of(cdev, struct mt6323_led, cdev);
+       struct mt6323_leds *leds = led->parent;
+       struct regmap *regmap = leds->hw->regmap;
+       unsigned long period;
+       u8 duty_hw;
+       int ret;
+
+       /*
+        * Units are in ms, if over the hardware able
+        * to support, fallback into software blink
+        */
+       period = *delay_on + *delay_off;
+
+       if (period > MT6323_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 && !*delay_off) {
+               *delay_on = 500;
+               *delay_off = 500;
+       }
+
+       /*
+        * Calculate duty_hw based on the percentage of period during
+        * which the led is ON.
+        */
+       duty_hw = MT6323_CAL_HW_DUTY(*delay_on, period);
+
+       /* hardware doesn't support zero duty cycle. */
+       if (!duty_hw)
+               return -EINVAL;
+
+       mutex_lock(&leds->lock);
+       /*
+        * Set max_brightness as the software blink behavior
+        * when no blink brightness.
+        */
+       if (!led->current_brightness) {
+               ret = mt6323_led_hw_on(cdev, cdev->max_brightness);
+               if (ret < 0)
+                       goto out;
+               led->current_brightness = cdev->max_brightness;
+       }
+
+       ret = regmap_update_bits(regmap, MT6323_ISINK_CON0(led->id),
+                                MT6323_ISINK_DIM_DUTY_MASK,
+                                MT6323_ISINK_DIM_DUTY(duty_hw - 1));
+       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 mt6323_led_set_brightness(struct led_classdev *cdev,
+                                    enum led_brightness brightness)
+{
+       struct mt6323_led *led = container_of(cdev, struct mt6323_led, cdev);
+       struct mt6323_leds *leds = led->parent;
+       int ret;
+
+       mutex_lock(&leds->lock);
+
+       if (!led->current_brightness && brightness) {
+               ret = mt6323_led_hw_on(cdev, brightness);
+               if (ret < 0)
+                       goto out;
+       } else if (brightness) {
+               ret = mt6323_led_hw_brightness(cdev, brightness);
+               if (ret < 0)
+                       goto out;
+       } else {
+               ret = mt6323_led_hw_off(cdev);
+               if (ret < 0)
+                       goto out;
+       }
+
+       led->current_brightness = brightness;
+out:
+       mutex_unlock(&leds->lock);
+
+       return ret;
+}
+
+static int mt6323_led_set_dt_default(struct led_classdev *cdev,
+                                    struct device_node *np)
+{
+       struct mt6323_led *led = container_of(cdev, struct mt6323_led, cdev);
+       const char *state;
+       int ret = 0;
+
+       led->cdev.name = of_get_property(np, "label", NULL) ? : np->name;
+       led->cdev.default_trigger = of_get_property(np,
+                                                   "linux,default-trigger",
+                                                   NULL);
+
+       state = of_get_property(np, "default-state", NULL);
+       if (state) {
+               if (!strcmp(state, "keep")) {
+                       ret = mt6323_get_led_hw_brightness(cdev);
+                       if (ret < 0)
+                               return ret;
+                       led->current_brightness = ret;
+                       ret = 0;
+               } else if (!strcmp(state, "on")) {
+                       ret =
+                       mt6323_led_set_brightness(cdev, cdev->max_brightness);
+               } else  {
+                       ret = mt6323_led_set_brightness(cdev, LED_OFF);
+               }
+       }
+
+       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 mt6323_leds *leds;
+       struct mt6323_led *led;
+       int ret;
+       unsigned int status;
+       u32 reg;
+
+       leds = devm_kzalloc(dev, sizeof(*leds), 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);
+
+       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) {
+               ret = of_property_read_u32(child, "reg", &reg);
+               if (ret) {
+                       dev_err(dev, "Failed to read led 'reg' property\n");
+                       goto put_child_node;
+               }
+
+               if (reg < 0 || reg > MT6323_MAX_LEDS || leds->led[reg]) {
+                       dev_err(dev, "Invalid led reg %u\n", reg);
+                       ret = -EINVAL;
+                       goto put_child_node;
+               }
+
+               led = devm_kzalloc(dev, sizeof(*led), GFP_KERNEL);
+               if (!led) {
+                       ret = -ENOMEM;
+                       goto put_child_node;
+               }
+
+               leds->led[reg] = led;
+               leds->led[reg]->id = reg;
+               leds->led[reg]->cdev.max_brightness = MT6323_MAX_BRIGHTNESS;
+               leds->led[reg]->cdev.brightness_set_blocking =
+                                       mt6323_led_set_brightness;
+               leds->led[reg]->cdev.blink_set = mt6323_led_set_blink;
+               leds->led[reg]->cdev.brightness_get =
+                                       mt6323_get_led_hw_brightness;
+               leds->led[reg]->parent = leds;
+
+               ret = mt6323_led_set_dt_default(&leds->led[reg]->cdev, child);
+               if (ret < 0) {
+                       dev_err(leds->dev,
+                               "Failed to LED set default from devicetree\n");
+                       goto put_child_node;
+               }
+
+               ret = devm_led_classdev_register(dev, &leds->led[reg]->cdev);
+               if (ret) {
+                       dev_err(&pdev->dev, "Failed to register LED: %d\n",
+                               ret);
+                       goto put_child_node;
+               }
+               leds->led[reg]->cdev.dev->of_node = child;
+       }
+
+       return 0;
+
+put_child_node:
+       of_node_put(child);
+       return ret;
+}
+
+static int mt6323_led_remove(struct platform_device *pdev)
+{
+       struct mt6323_leds *leds = platform_get_drvdata(pdev);
+       int i;
+
+       /* Turn the LEDs off on driver removal. */
+       for (i = 0 ; leds->led[i] ; i++)
+               mt6323_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.w...@mediatek.com>");
+MODULE_LICENSE("GPL");
-- 
1.9.1

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