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

From: Sean Wang
Date: Sat Jan 28 2017 - 09:12:00 EST

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In reply to: Jacek Anaszewski: "Re: [PATCH 3/4] leds: Add LED support for MT6323 PMIC"
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Hi Jacek,

thanks for your effort on reviewing
I has given these idea about your questions inline below
and will fix up these explicit mistakes in the next version.

thanks again

On Tue, 2017-01-24 at 23:51 +0100, Jacek Anaszewski wrote:
> Hi Sean,
>
> Thanks for the patch. Please find my comments in the code below.
>
> On 01/23/2017 04:54 AM, sean.wang@xxxxxxxxxxxx wrote:
> > From: Sean Wang <sean.wang@xxxxxxxxxxxx>
> >
> > MT6323 PMIC is a multi-function device that includes
> > LED function. It allows attaching upto 4 LEDs which can
>
> s/upto/up to/
>
will be fixed

> > either be on, off or dimmed and/or blinked with the the
> > controller.
> >
> > Signed-off-by: Sean Wang <sean.wang@xxxxxxxxxxxx>
> > ---
> > drivers/leds/Kconfig | 8 +
> > drivers/leds/Makefile | 1 +
> > drivers/leds/leds-mt6323.c | 391 +++++++++++++++++++++++++++++++++++++++++++++
> > 3 files changed, 400 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..de3006d
> > --- /dev/null
> > +++ b/drivers/leds/leds-mt6323.c
> > @@ -0,0 +1,391 @@
> > +/*
> > + * LED driver for Mediatek MT6323 PMIC
> > + *
> > + * Copyright (C) 2017 Sean Wang <sean.wang@xxxxxxxxxxxx>
> > + *
> > + * 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/of.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/leds.h>
> > +#include <linux/regmap.h>
> > +#include <linux/mfd/mt6397/core.h>
> > +#include <linux/mfd/mt6323/registers.h>
> > +#include <linux/module.h>
>
> Please sort include directives alphabetically.
>
will be fixed

> > +
> > +/* 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.

MT6323_TOP_CKPDN0 had been defined in regulator header files
but your idea is good where reusing them is better .

Will be enhanced.

> > +#define RG_DRV_32K_CK_PDN BIT(11)
> > +#define RG_DRV_32K_CK_PDN_MASK BIT(11)
>
> These macros also require MT6323 prefix.

Will be enhanced

> > +
> > +/* 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.
>
Will be fixed

> > +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:
>
> /**
> *

Will be fixed

> > + * of the driver
> > + * @dev: The device pointer
> > + * @hw: The underlying hardware providing shared
> > + bus for the register operations
>
> leading " *" is missing here
>

Will be fixed

> > + * @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.
>

Will be fixed

> > + */
> > +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.

Will be fixed and applied to all the occurrences where regmap API being
used.

> > +
> > + usleep_range(100, 300);
>
> Just out of curiosity - does the data sheet mention it or is it inferred
> empirically?
>

it comes from that inferred empirically.
leds can't being light on if without the delay

> > + 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.
>

will be removed

> > +}
> > +
> > +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.
>

will be fixed

> > +}
> > +
> > +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).
>

will be fixed and applied to all occurrences

> > + * 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.
>

will be removed

> > +}
> > +
> > +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.
>

will be fixed

> > + 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.
>

will be removed

> > +
> > + 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.
>

will be removed

> > + }
> > +
> > + if (!brightness)
> > + mtk_led_hw_off(cdev);
>
> It could be enclosed in "else " case of the above "if (brightness)"
> condition.
>
good suggestion. will be enhanced

> > + 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?

it is also from inferred empirically but that could be removed
because 32k clock should be stable before the hardware is being
enabled.

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

will be fixed

> > + * 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/

will be fixed
> > + 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.
>

will be fixed
> > + 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@xxxxxxxxxxxx>");
> > +MODULE_LICENSE("GPL v2");
>
> MODULE_LICENSE("GPL") since you are allowing also later version.
>

will be fixed

> 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
>

will be fixed

Next message: Jonathan Cameron: "Re: [PATCH 1/7] iio: adc: stm32: add support for triggered buffer mode"
Previous message: Bhumika Goyal: "[PATCH] regulator: gpio-regulator: constify regulator_ops structure"
In reply to: Jacek Anaszewski: "Re: [PATCH 3/4] leds: Add LED support for MT6323 PMIC"
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