[PATCH v4 3/4] leds: Add LED support for MT6323 PMIC

sean.wang
2017-02-24T18:48:32Z

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.wang@mediatek.com>
---
drivers/leds/Kconfig | 8 +
drivers/leds/Makefile | 1 +
drivers/leds/leds-mt6323.c | 500 +++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 509 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..7274581
--- /dev/null
+++ b/drivers/leds/leds-mt6323.c
@@ -0,0 +1,500 @@
+/*
+ * 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 MT6323_MAX_PERIOD 10000
+#define MT6323_MAX_LEDS 4
+#define MT6323_MAX_BRIGHTNESS 6
+#define MT6323_UNIT_DUTY 3125
+
+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;
+ 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 > 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;
+ }
+
+ period = *delay_on + *delay_off;
+ /*
+ * duty_cycle is the percentage of period during
+ * which the led is ON.
+ */
+ duty_cycle = 100 * (*delay_on) / period;
+
+ /* hardware doesn't support zero duty cycle. */
+ if (!duty_cycle)
+ 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;
+ }
+
+ duty_hw = DIV_ROUND_CLOSEST(duty_cycle * 1000, MT6323_UNIT_DUTY);
+ 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");
+ return ret;
+ }
+
+ ret = devm_led_classdev_register(dev, &leds->led[reg]->cdev);
+ if (ret) {
+ dev_err(&pdev->dev, "Failed to register LED: %d\n",
+ ret);
+ return ret;
+ }
+ 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.wang@mediatek.com>");
+MODULE_LICENSE("GPL");
--
1.9.1