Re: [RESUBMIT PATCH v3 2/8] backlight: Add support Skyworks SKY81452 backlight driver

[Jingoo Han <jg1.han-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>]

On Tuesday, October 07, 2014 2:01 PM, Gyungoh Yoo wrote:
> 

If possible, please add more detailed commit message for this patch.

> Signed-off-by: Gyungoh Yoo <jack.yoo-tjhQNA90jdKqndwCJWfcng@public.gmane.org>
> ---
>  drivers/video/backlight/Kconfig              |  10 +
>  drivers/video/backlight/Makefile             |   1 +
>  drivers/video/backlight/sky81452-backlight.c | 347 +++++++++++++++++++++++++++
>  3 files changed, 358 insertions(+)
>  create mode 100644 drivers/video/backlight/sky81452-backlight.c
> 
> diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig
> index 8d03924..2586fdd 100644
> --- a/drivers/video/backlight/Kconfig
> +++ b/drivers/video/backlight/Kconfig
> @@ -409,6 +409,16 @@ config BACKLIGHT_PANDORA
>  	  If you have a Pandora console, say Y to enable the
>  	  backlight driver.
> 
> +config BACKLIGHT_SKY81452
> +	tristate "Backlight driver for SKY81452"
> +	depends on BACKLIGHT_CLASS_DEVICE && MFD_SKY81452
> +	help
> +	  If you have a Skyworks SKY81452, say Y to enable the
> +	  backlight driver.
> +
> +	  To compile this driver as a module, choose M here: the module will
> +	  be called sky81452-backlight
> +
>  config BACKLIGHT_TPS65217
>  	tristate "TPS65217 Backlight"
>  	depends on BACKLIGHT_CLASS_DEVICE && MFD_TPS65217
> diff --git a/drivers/video/backlight/Makefile b/drivers/video/backlight/Makefile
> index fcd50b73..d67073f 100644
> --- a/drivers/video/backlight/Makefile
> +++ b/drivers/video/backlight/Makefile
> @@ -50,6 +50,7 @@ obj-$(CONFIG_BACKLIGHT_PANDORA)		+= pandora_bl.o
>  obj-$(CONFIG_BACKLIGHT_PCF50633)	+= pcf50633-backlight.o
>  obj-$(CONFIG_BACKLIGHT_PWM)		+= pwm_bl.o
>  obj-$(CONFIG_BACKLIGHT_SAHARA)		+= kb3886_bl.o
> +obj-$(CONFIG_BACKLIGHT_SKY81452)	+= sky81452-backlight.o
>  obj-$(CONFIG_BACKLIGHT_TOSA)		+= tosa_bl.o
>  obj-$(CONFIG_BACKLIGHT_TPS65217)	+= tps65217_bl.o
>  obj-$(CONFIG_BACKLIGHT_WM831X)		+= wm831x_bl.o
> diff --git a/drivers/video/backlight/sky81452-backlight.c b/drivers/video/backlight/sky81452-
> backlight.c
> new file mode 100644
> index 0000000..101399d
> --- /dev/null
> +++ b/drivers/video/backlight/sky81452-backlight.c
> @@ -0,0 +1,347 @@
> +/*
> + * sky81452-backlight.c	SKY81452 backlight driver
> + *
> + * Copyright 2014 Skyworks Solutions Inc.
> + * Author : Gyungoh Yoo <jack.yoo-tjhQNA90jdKqndwCJWfcng@public.gmane.org>
> + *
> + * 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, 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.
> + *
> + * You should have received a copy of the GNU General Public License along
> + * with this program; if not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/init.h>
> +#include <linux/platform_device.h>
> +#include <linux/slab.h>
> +#include <linux/of.h>
> +#include <linux/err.h>
> +#include <linux/gpio.h>
> +#include <linux/of_gpio.h>
> +#include <linux/regmap.h>
> +#include <linux/backlight.h>
> +#include <linux/sky81452-backlight.h>

Please, re-order these headers alphabetically.
It enhances the readability.

> +
> +/* registers */
> +#define SKY81452_REG0	0x00
> +#define SKY81452_REG1	0x01
> +#define SKY81452_REG2	0x02
> +#define SKY81452_REG4	0x04
> +#define SKY81452_REG5	0x05
> +
> +/* bit mask */
> +#define SKY81452_CS	0xFF
> +#define SKY81452_EN	0x3F
> +#define SKY81452_IGPW	0x20
> +#define SKY81452_PWMMD	0x10
> +#define SKY81452_PHASE	0x08
> +#define SKY81452_ILIM	0x04
> +#define SKY81452_VSHRT	0x03
> +#define SKY81452_OCP	0x80
> +#define SKY81452_OTMP	0x40
> +#define SKY81452_SHRT	0x3F
> +#define SKY81452_OPN	0x3F
> +
> +#define SKY81452_DEFAULT_NAME "lcd-backlight"
> +#define SKY81452_MAX_BRIGHTNESS	(SKY81452_CS + 1)
> +
> +#define CTZ(b) __builtin_ctz(b)
> +
> +static int sky81452_bl_update_status(struct backlight_device *bd)
> +{
> +	const struct sky81452_bl_platform_data *pdata =
> +			dev_get_platdata(bd->dev.parent);
> +	const unsigned int brightness = (unsigned int)bd->props.brightness;
> +	struct regmap *regmap = bl_get_data(bd);
> +	int ret;
> +
> +	if (brightness > 0) {
> +		ret = regmap_write(regmap, SKY81452_REG0, brightness - 1);
> +		if (IS_ERR_VALUE(ret))
> +			return ret;
> +
> +		return regmap_update_bits(regmap, SKY81452_REG1, SKY81452_EN,
> +					pdata->enable << CTZ(SKY81452_EN));
> +	}
> +
> +	return regmap_update_bits(regmap, SKY81452_REG1, SKY81452_EN, 0);
> +}
> +
> +static int sky81452_bl_get_brightness(struct backlight_device *bd)
> +{
> +	return bd->props.brightness;
> +}
> +
> +static const struct backlight_ops sky81452_bl_ops = {
> +	.update_status = sky81452_bl_update_status,
> +	.get_brightness = sky81452_bl_get_brightness,
> +};
> +
> +static ssize_t sky81452_bl_store_enable(struct device *dev,
> +		struct device_attribute *attr, const char *buf, size_t count)
> +{
> +	struct regmap *regmap = bl_get_data(to_backlight_device(dev));
> +	unsigned long value;
> +	int ret;
> +
> +	ret = kstrtoul(buf, 16, &value);
> +	if (IS_ERR_VALUE(ret))
> +		return ret;
> +
> +	ret = regmap_update_bits(regmap, SKY81452_REG1, SKY81452_EN,
> +					value << CTZ(SKY81452_EN));
> +	if (IS_ERR_VALUE(ret))
> +		return ret;
> +
> +	return count;
> +}
> +
> +static ssize_t sky81452_bl_show_open_short(struct device *dev,
> +		struct device_attribute *attr, char *buf)
> +{
> +	struct regmap *regmap = bl_get_data(to_backlight_device(dev));
> +	unsigned int reg, value = 0;
> +	char tmp[3];
> +	int i, ret;
> +
> +	reg = !strcmp(attr->attr.name, "open") ? SKY81452_REG5 : SKY81452_REG4;
> +	ret = regmap_read(regmap, reg, &value);
> +	if (IS_ERR_VALUE(ret))
> +		return ret;
> +
> +	if (value & SKY81452_SHRT) {
> +		*buf = 0;
> +		for (i = 0; i < 6; i++) {
> +			if (value & 0x01) {
> +				sprintf(tmp, "%d ", i + 1);
> +				strcat(buf, tmp);
> +			}
> +			value >>= 1;
> +		}
> +		strcat(buf, "\n");
> +	} else
> +		strcpy(buf, "none\n");

Please add braces to 'else' statement. 

If only one branch of a conditional statement is a single
statement. Braces are needed.

	if () {
		... (multi lines)
	} else {
		...
	}


> +
> +	return strlen(buf);
> +}
> +
> +static ssize_t sky81452_bl_show_fault(struct device *dev,
> +		struct device_attribute *attr, char *buf)
> +{
> +	struct regmap *regmap = bl_get_data(to_backlight_device(dev));
> +	unsigned int value = 0;
> +	int ret;
> +
> +	ret = regmap_read(regmap, SKY81452_REG4, &value);
> +	if (IS_ERR_VALUE(ret))
> +		return ret;
> +
> +	*buf = 0;
> +
> +	if (value & SKY81452_OCP)
> +		strcat(buf, "over-current ");
> +
> +	if (value & SKY81452_OTMP)
> +		strcat(buf, "over-temperature");
> +
> +	strcat(buf, "\n");
> +	return strlen(buf);
> +}
> +
> +static DEVICE_ATTR(enable, S_IWGRP | S_IWUSR, NULL, sky81452_bl_store_enable);
> +static DEVICE_ATTR(open, S_IRUGO, sky81452_bl_show_open_short, NULL);
> +static DEVICE_ATTR(short, S_IRUGO, sky81452_bl_show_open_short, NULL);
> +static DEVICE_ATTR(fault, S_IRUGO, sky81452_bl_show_fault, NULL);
> +
> +static struct attribute *sky81452_bl_attribute[] = {
> +	&dev_attr_enable.attr,
> +	&dev_attr_open.attr,
> +	&dev_attr_short.attr,
> +	&dev_attr_fault.attr,
> +	NULL
> +};
> +
> +static const struct attribute_group sky81452_bl_attr_group = {
> +	.attrs = sky81452_bl_attribute,
> +};
> +
> +#ifdef CONFIG_OF
> +static struct sky81452_bl_platform_data *sky81452_bl_parse_dt(
> +							struct device *dev)
> +{
> +	struct device_node *np = of_node_get(dev->of_node);
> +	struct sky81452_bl_platform_data *pdata;
> +	int ret;
> +
> +	if (!np) {
> +		dev_err(dev, "backlight node not found");
> +		return ERR_PTR(-ENODATA);
> +	}
> +
> +	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
> +	if (!pdata) {
> +		of_node_put(np);
> +		return ERR_PTR(-ENOMEM);
> +	}
> +
> +	of_property_read_string(np, "name", &pdata->name);
> +	pdata->ignore_pwm = of_property_read_bool(np, "ignore-pwm");
> +	pdata->dpwm_mode = of_property_read_bool(np, "dpwm-mode");
> +	pdata->phase_shift = of_property_read_bool(np, "phase-shift");
> +
> +	pdata->gpio_enable = of_get_named_gpio(np, "gpio-enable", 0);
> +	if (IS_ERR_VALUE(pdata->gpio_enable))
> +		pdata->gpio_enable = -1;
> +
> +	ret = of_property_read_u32(np, "enable", &pdata->enable);
> +	if (IS_ERR_VALUE(ret))
> +		pdata->enable = SKY81452_EN >> CTZ(SKY81452_EN);
> +
> +	ret = of_property_read_u32(np, "short-detection-threshold",
> +			&pdata->short_detection_threshold);
> +	if (IS_ERR_VALUE(ret))
> +		pdata->short_detection_threshold = 7;
> +
> +	ret = of_property_read_u32(np, "boost-current-limit",
> +			&pdata->boost_current_limit);
> +	if (IS_ERR_VALUE(ret))
> +		pdata->boost_current_limit = 2750;
> +
> +	of_node_put(np);
> +	return pdata;
> +}
> +#else
> +static struct sky81452_bl_platform_data *sky81452_bl_parse_dt(
> +							struct device *dev)
> +{
> +	return ERR_PTR(-EINVAL);
> +}
> +#endif
> +
> +static int sky81452_bl_init_device(struct regmap *regmap,
> +		struct sky81452_bl_platform_data *pdata)
> +{
> +	unsigned int value;
> +
> +	value = pdata->ignore_pwm ? SKY81452_IGPW : 0;
> +	value |= pdata->dpwm_mode ? SKY81452_PWMMD : 0;
> +	value |= pdata->phase_shift ? 0 : SKY81452_PHASE;
> +
> +	if (pdata->boost_current_limit == 2300)
> +		value |= SKY81452_ILIM;
> +	else if (pdata->boost_current_limit != 2720)
> +		return -EINVAL;
> +
> +	if (pdata->short_detection_threshold < 4 ||
> +				pdata->short_detection_threshold > 7)
> +		return -EINVAL;
> +	value |= (7 - pdata->short_detection_threshold) << CTZ(SKY81452_VSHRT);
> +
> +	return regmap_write(regmap, SKY81452_REG2, value);
> +}
> +
> +static int sky81452_bl_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct regmap *regmap = dev_get_drvdata(dev->parent);
> +	struct sky81452_bl_platform_data *pdata = dev_get_platdata(dev);
> +	struct backlight_device *bd;
> +	struct backlight_properties props;
> +	const char *name;
> +	int ret;
> +
> +	if (!pdata) {
> +		pdata = sky81452_bl_parse_dt(dev);
> +		if (IS_ERR(pdata))
> +			return PTR_ERR(pdata);
> +	}
> +
> +	if (pdata->gpio_enable >= 0) {
> +		ret = devm_gpio_request_one(dev, pdata->gpio_enable,
> +					GPIOF_OUT_INIT_HIGH, "sky81452-en");
> +		if (IS_ERR_VALUE(ret)) {
> +			dev_err(dev, "failed to request GPIO. err=%d", ret);
> +			return ret;
> +		}
> +	}
> +
> +	ret = sky81452_bl_init_device(regmap, pdata);
> +	if (IS_ERR_VALUE(ret)) {
> +		dev_err(dev, "failed to initialize. err=%d", ret);
> +		return ret;
> +	}
> +
> +	memset(&props, 0, sizeof(props));
> +	props.max_brightness = SKY81452_MAX_BRIGHTNESS,
> +	name = pdata->name ? pdata->name : SKY81452_DEFAULT_NAME;
> +	bd = devm_backlight_device_register(dev, name, dev, regmap,
> +						&sky81452_bl_ops, &props);
> +	if (IS_ERR(bd)) {
> +		dev_err(dev, "failed to register. err=%ld", PTR_ERR(bd));
> +		return PTR_ERR(bd);
> +	}
> +
> +	platform_set_drvdata(pdev, bd);
> +
> +	ret  = sysfs_create_group(&bd->dev.kobj, &sky81452_bl_attr_group);
> +	if (IS_ERR_VALUE(ret)) {
> +		dev_err(dev, "failed to create attribute. err=%d", ret);
> +		goto err;
> +	}
> +
> +	return ret;
> +err:
> +	backlight_device_unregister(bd);

This backlight_device_unregister() is NOT necessary.
This is because backlight_device_unregister will be called
automatically, when devm_backlight_device_register() is used
and error returns.

> +	return ret;
> +}
> +
> +static int sky81452_bl_remove(struct platform_device *pdev)
> +{
> +	const struct sky81452_bl_platform_data *pdata =
> +						dev_get_platdata(&pdev->dev);
> +	struct backlight_device *bd = platform_get_drvdata(pdev);
> +
> +	sysfs_remove_group(&bd->dev.kobj, &sky81452_bl_attr_group);
> +
> +	bd->props.power = FB_BLANK_UNBLANK;
> +	bd->props.brightness = 0;
> +	backlight_update_status(bd);
> +
> +	if (pdata->gpio_enable >= 0)
> +		gpio_set_value_cansleep(pdata->gpio_enable, 0);
> +
> +	return 0;
> +}
> +
> +#ifdef CONFIG_OF
> +static const struct of_device_id sky81452_bl_of_match[] = {
> +	{ .compatible = "skyworks,sky81452-backlight", },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(of, sky81452_bl_of_match);
> +#endif
> +
> +static struct platform_driver sky81452_bl_driver = {
> +	.driver = {
> +		.name = "sky81452-backlight",
> +		.of_match_table = of_match_ptr(sky81452_bl_of_match),
> +	},
> +	.probe = sky81452_bl_probe,
> +	.remove = sky81452_bl_remove,
> +};
> +
> +module_platform_driver(sky81452_bl_driver);
> +
> +MODULE_DESCRIPTION("Skyworks SKY81452 backlight driver");
> +MODULE_AUTHOR("Gyungoh Yoo <jack.yoo-tjhQNA90jdKqndwCJWfcng@public.gmane.org>");
> +MODULE_LICENSE("GPL");

How about using 'GPL v2'?

> +MODULE_VERSION("1.2");
> --
> 1.9.1

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