Hi Sean,

Thanks for the patch. Please find my comments in the code below.

On 01/23/2017 04:54 AM, sean.wang@mediatek.com wrote:

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

s/upto/up to/

Please sort include directives alphabetically.

+
+/* Register to enable 32K clock common for LED device */
+#define MTK_MT6323_TOP_CKPDN0         0x0102

How about dropping MTK and leaving MT6323 prefix?
The same applies to the other macros.

+#define RG_DRV_32K_CK_PDN	      BIT(11)
+#define RG_DRV_32K_CK_PDN_MASK	      BIT(11)

These macros also require MT6323 prefix.

+
+/* Register to enable individual clock for LED device */
+#define MTK_MT6323_TOP_CKPDN2         0x010E
+#define RG_ISINK_CK_PDN(i)	      BIT(i)
+#define RG_ISINK_CK_PDN_MASK(i)       BIT(i)
+
+/* Register to select clock source */
+#define MTK_MT6323_TOP_CKCON1	      0x0126
+#define RG_ISINK_CK_SEL_MASK(i)	      (BIT(10) << (i))
+
+/* Register to setup the duty cycle of the blink */
+#define MTK_MT6323_ISINK_CON0(i)      (0x0330 + 0x8 * (i))
+#define ISINK_DIM_DUTY(i)	      (((i) << 8) & GENMASK(12, 8))
+#define ISINK_DIM_DUTY_MASK	      GENMASK(12, 8)
+
+/* Register to setup the period of the blink */
+#define MTK_MT6323_ISINK_CON1(i)      (0x0332 + 0x8 * (i))
+#define ISINK_DIM_FSEL(i)	      ((i) & GENMASK(15, 0))
+#define ISINK_DIM_FSEL_MASK	      GENMASK(15, 0)
+
+/* Register to control the brightness */
+#define MTK_MT6323_ISINK_CON2(i)      (0x0334 + 0x8 * (i))
+#define ISINK_CH_STEP(i)	      (((i) << 12) & GENMASK(14, 12))
+#define ISINK_CH_STEP_MASK	      GENMASK(14, 12)
+#define ISINK_SFSTR0_TC(i)	      (((i) << 1) & GENMASK(2, 1))
+#define ISINK_SFSTR0_TC_MASK	      GENMASK(2, 1)
+#define ISINK_SFSTR0_EN		      BIT(0)
+#define ISINK_SFSTR0_EN_MASK	      BIT(0)
+
+/* Register to LED channel enablement */
+#define MTK_MT6323_ISINK_EN_CTRL      0x0356
+#define ISINK_CH_EN(i)		      BIT(i)
+#define ISINK_CH_EN_MASK(i)	      BIT(i)
+
+#define MTK_MAX_PERIOD		      10000
+#define MTK_MAX_DEVICES			  4
+#define MTK_MAX_BRIGHTNESS		  6
+
+struct mtk_led;

This is redundant.

+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

Please stick to the kernel doc format consistently:

/**
 *

+ *			of the driver
+ * @dev:		The device pointer
+ * @hw:			The underlying hardware providing shared
+			bus for the register operations

leading " *" is missing here

+ * @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

Ditto.

+ */
+struct mtk_leds {
+	struct device	*dev;
+	struct mt6397_chip *hw;
+	u8     led_num;
+	/* protect among process context */
+	struct mutex	 lock;
+	struct mtk_led	 led[4];
+};
+
+static void 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;
+
+	status = ISINK_CH_EN(led->id);
+	regmap_update_bits(regmap, MTK_MT6323_ISINK_EN_CTRL,
+			   ISINK_CH_EN_MASK(led->id), ~status);

Let's check return value. The same applies the other occurrences
of regmap API calls.

+
+	usleep_range(100, 300);

Just out of curiosity - does the data sheet mention it or is it inferred
empirically?

+	regmap_update_bits(regmap, MTK_MT6323_TOP_CKPDN2,
+			   RG_ISINK_CK_PDN_MASK(led->id),
+			   RG_ISINK_CK_PDN(led->id));
+
+	dev_dbg(leds->dev, "%s called for led%d\n",
+		__func__, led->id);

Let's remove this debug logging.

+}
+
+static u8 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;
+
+	regmap_read(regmap, MTK_MT6323_TOP_CKPDN2, &status);
+	if (status & RG_ISINK_CK_PDN_MASK(led->id))
+		return 0;
+
+	regmap_read(regmap, MTK_MT6323_ISINK_EN_CTRL, &status);
+	if (!(status & ISINK_CH_EN(led->id)))
+		return 0;
+
+	regmap_read(regmap, MTK_MT6323_ISINK_CON2(led->id), &status);
+	return  ((status & ISINK_CH_STEP_MASK) >> 12) + 1;

What is 12? Please add a macro for it.

+}
+
+static void 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;
+
+	/* Setup required clock source, enable the corresponding

Kernel style comments please:

/*
 *
 */

The same applies to the other occurrences thereof.
Refer to Documentation/process/coding-style.rst (chapter 8).

+	 * clock and channel and let work with continuous blink as
+	 * the default
+	 */
+	regmap_update_bits(regmap, MTK_MT6323_TOP_CKCON1,
+			   RG_ISINK_CK_SEL_MASK(led->id), 0);
+
+	status = RG_ISINK_CK_PDN(led->id);
+	regmap_update_bits(regmap, MTK_MT6323_TOP_CKPDN2,
+			   RG_ISINK_CK_PDN_MASK(led->id), ~status);
+
+	usleep_range(100, 300);
+
+	regmap_update_bits(regmap, MTK_MT6323_ISINK_EN_CTRL,
+			   ISINK_CH_EN_MASK(led->id),
+			   ISINK_CH_EN(led->id));
+
+	regmap_update_bits(regmap, MTK_MT6323_ISINK_CON2(led->id),
+			   ISINK_CH_STEP_MASK,
+			   ISINK_CH_STEP(1));
+
+	regmap_update_bits(regmap, MTK_MT6323_ISINK_CON0(led->id),
+			   ISINK_DIM_DUTY_MASK, ISINK_DIM_DUTY(31));
+
+	regmap_update_bits(regmap, MTK_MT6323_ISINK_CON1(led->id),
+			   ISINK_DIM_FSEL_MASK, ISINK_DIM_FSEL(1000));
+
+	led->current_brightness = 1;
+
+	dev_dbg(leds->dev, "%s called for led%d\n",
+		__func__, led->id);

Let's remove this debug logging.

+}
+
+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;
+
+	/* 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)
+		mtk_led_hw_on(cdev);
+
+	duty_hw = DIV_ROUND_CLOSEST(duty_cycle * 1000, 3125);

Please add a macro for 3125.

+	regmap_update_bits(regmap, MTK_MT6323_ISINK_CON0(led->id),
+			   ISINK_DIM_DUTY_MASK, ISINK_DIM_DUTY(duty_hw));
+
+	regmap_update_bits(regmap, MTK_MT6323_ISINK_CON1(led->id),
+			   ISINK_DIM_FSEL_MASK, ISINK_DIM_FSEL(period - 1));
+
+	mutex_unlock(&leds->lock);
+
+	dev_dbg(leds->dev, "%s: Hardware blink! period=%dms duty=%d for led%d\n",
+		__func__, period, duty_cycle, led->id);

Let's remove this debug logging.

+
+	return 0;
+}
+
+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;
+
+	mutex_lock(&leds->lock);
+
+	if (!led->current_brightness && brightness)
+		mtk_led_hw_on(cdev);
+
+	if (brightness) {
+		/* Setup current output for the corresponding
+		 * brightness level
+		 */
+		regmap_update_bits(regmap, MTK_MT6323_ISINK_CON2(led->id),
+				   ISINK_CH_STEP_MASK,
+				   ISINK_CH_STEP(brightness - 1));
+
+		regmap_update_bits(regmap, MTK_MT6323_ISINK_CON2(led->id),
+				   ISINK_SFSTR0_TC_MASK | ISINK_SFSTR0_EN_MASK,
+				   ISINK_SFSTR0_TC(2) | ISINK_SFSTR0_EN);
+
+		dev_dbg(leds->dev, "Update led brightness:%d\n",
+			brightness);

Let's remove this debug logging.

+	}
+
+	if (!brightness)
+		mtk_led_hw_off(cdev);

It could be enclosed in "else " case of the above "if (brightness)"
condition.

+	led->current_brightness = brightness;
+
+	mutex_unlock(&leds->lock);
+
+	return 0;
+}
+
+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 = RG_DRV_32K_CK_PDN;
+	regmap_update_bits(leds->hw->regmap, MTK_MT6323_TOP_CKPDN0,
+			   RG_DRV_32K_CK_PDN_MASK, ~status);
+
+	/* Waiting for 32K stable prior to give the default value

Could you shed more light on this statement? How data sheet explains
that?

+	 * to each LED state decided through these useful common
+	 * propertys such as label, linux,default-trigger and

s/propertys/properties/

+	 * default-state
+	 */
+	usleep_range(300, 500);
+
+	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 if driver removal */

s/if/on/

+	for (i = 0 ; i < leds->led_num ; i++)
+		mtk_led_hw_off(&leds->led[i].cdev);
+
+	regmap_update_bits(leds->hw->regmap, MTK_MT6323_TOP_CKPDN0,
+			   RG_DRV_32K_CK_PDN_MASK, RG_DRV_32K_CK_PDN);

Please add mutex_destroy here.

+	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 [off-list ref]");
+MODULE_LICENSE("GPL v2");

MODULE_LICENSE("GPL") since you are allowing also later version.

Please also adress the following sparse warnings:

drivers/leds/leds-mt6323.c:166:9: warning: cast truncates bits from
constant value (7ffffffff000 becomes fffff000)
drivers/leds/leds-mt6323.c:170:9: warning: cast truncates bits from
constant value (1fffffffff00 becomes ffffff00)
drivers/leds/leds-mt6323.c:173:9: warning: cast truncates bits from
constant value (ffffffffffff becomes ffffffff)
drivers/leds/leds-mt6323.c:221:9: warning: cast truncates bits from
constant value (1fffffffff00 becomes ffffff00)
drivers/leds/leds-mt6323.c:224:9: warning: cast truncates bits from
constant value (ffffffffffff becomes ffffffff)
drivers/leds/leds-mt6323.c:251:17: warning: cast truncates bits from
constant value (7ffffffff000 becomes fffff000)
drivers/leds/leds-mt6323.c:255:17: warning: cast truncates bits from
constant value (7ffffffff becomes ffffffff

-- 
Best regards,
Jacek Anaszewski