Re: [PATCH v9 2/8] backlight: Add support Skyworks SKY81452 backlight driver

From: Jingoo Han
Date: Tue Dec 02 2014 - 21:18:00 EST

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On Tuesday, December 02, 2014 5:05 PM, Gyungoh Yoo wrote:
>
> From: Gyungoh Yoo <jack.yoo@xxxxxxxxxxxxxxx>
>
> Signed-off-by: Gyungoh Yoo <jack.yoo@xxxxxxxxxxxxxxx>
> ---
> Changes v9:
> Nothing
>
> Changes v8:
> Renamed property names for backlight with vendor prefix
> Modified gpio-enable property to generic property for GPIO
>
> Changes v7:
> Modified licensing text to GPLv2
>
> Changes v6:
> Added new line character at the end of line of dev_err()
>
> Changes v5:
> Move sky81452-backlight.h to include/linux/platform_data
>
> Changes v4:
> Reordering header files for readability
> Removed calling to backlight_device_unregister()
> Removed MODULE_VERSION()
> Modified license to GPLv2
>
> Changes v3:
> Modified DBG messages
>
> Changes v2:
> Added 'compatible' attribute in the driver
> Added message for exception or errors
>
> drivers/video/backlight/Kconfig | 10 +
> drivers/video/backlight/Makefile | 1 +
> drivers/video/backlight/sky81452-backlight.c | 340 +++++++++++++++++++++++
> include/linux/platform_data/sky81452-backlight.h | 46 +++
> 4 files changed, 397 insertions(+)
> create mode 100644 drivers/video/backlight/sky81452-backlight.c
> create mode 100644 include/linux/platform_data/sky81452-backlight.h
>
> 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..45e575f
> --- /dev/null
> +++ b/drivers/video/backlight/sky81452-backlight.c
> @@ -0,0 +1,340 @@
> +/*
> + * sky81452-backlight.c SKY81452 backlight driver
> + *
> + * Copyright 2014 Skyworks Solutions Inc.
> + * Author : Gyungoh Yoo <jack.yoo@xxxxxxxxxxxxxxx>
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms of the GNU General Public License version 2
> + * as published by the Free Software Foundation.
> + *
> + * 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/backlight.h>
> +#include <linux/err.h>
> +#include <linux/gpio.h>
> +#include <linux/init.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_gpio.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +#include <linux/platform_data/sky81452-backlight.h>
> +#include <linux/slab.h>
> +
> +/* 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;
> +}

Please remove sky81452_bl_get_brightness().
In the case of just returning 'props.brightness',
backglight core can also return 'props.brightness'.
So, there is no need to add sky81452_bl_get_brightness().

Please refer to the following patches.
backlight: Remove trivial get_brightness implementations
backlight: Show brightness even if get_brightness is not implemented

Others look good.
Thanks.

Best regards,
Jingoo Han

> +
> +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");
> + }
> +
> + 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.\n");
> + 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, "skyworks,ignore-pwm");
> + pdata->dpwm_mode = of_property_read_bool(np, "skyworks,dpwm-mode");
> + pdata->phase_shift = of_property_read_bool(np, "skyworks,phase-shift");
> + pdata->gpio_enable = of_get_gpio(np, 0);
> +
> + ret = of_property_read_u32(np, "skyworks,en-channels", &pdata->enable);
> + if (IS_ERR_VALUE(ret))
> + pdata->enable = SKY81452_EN >> CTZ(SKY81452_EN);
> +
> + ret = of_property_read_u32(np, "skyworks,short-detection-threshold",
> + &pdata->short_detection_threshold);
> + if (IS_ERR_VALUE(ret))
> + pdata->short_detection_threshold = 7;
> +
> + ret = of_property_read_u32(np, "skyworks,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 != 2750)
> + 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 (gpio_is_valid(pdata->gpio_enable)) {
> + 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\n", ret);
> + return ret;
> + }
> + }
> +
> + ret = sky81452_bl_init_device(regmap, pdata);
> + if (IS_ERR_VALUE(ret)) {
> + dev_err(dev, "failed to initialize. err=%d\n", 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\n", 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\n", ret);
> + return ret;
> + }
> +
> + 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 (gpio_is_valid(pdata->gpio_enable))
> + 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@xxxxxxxxxxxxxxx>");
> +MODULE_LICENSE("GPL v2");
> diff --git a/include/linux/platform_data/sky81452-backlight.h b/include/linux/platform_data/sky81452-
> backlight.h
> new file mode 100644
> index 0000000..1231e9b
> --- /dev/null
> +++ b/include/linux/platform_data/sky81452-backlight.h
> @@ -0,0 +1,46 @@
> +/*
> + * sky81452.h SKY81452 backlight driver
> + *
> + * Copyright 2014 Skyworks Solutions Inc.
> + * Author : Gyungoh Yoo <jack.yoo@xxxxxxxxxxxxxxx>
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms of the GNU General Public License version 2
> + * as published by the Free Software Foundation.
> + *
> + * 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/>.
> + */
> +
> +#ifndef _SKY81452_BACKLIGHT_H
> +#define _SKY81452_BACKLIGHT_H
> +
> +/**
> + * struct sky81452_platform_data
> + * @name: backlight driver name.
> + If it is not defined, default name is lcd-backlight.
> + * @gpio_enable:GPIO number which control EN pin
> + * @enable: Enable mask for current sink channel 1, 2, 3, 4, 5 and 6.
> + * @ignore_pwm: true if DPWMI should be ignored.
> + * @dpwm_mode: true is DPWM dimming mode, otherwise Analog dimming mode.
> + * @phase_shift:true is phase shift mode.
> + * @short_detecion_threshold: It should be one of 4, 5, 6 and 7V.
> + * @boost_current_limit: It should be one of 2300, 2750mA.
> + */
> +struct sky81452_bl_platform_data {
> + const char *name;
> + int gpio_enable;
> + unsigned int enable;
> + bool ignore_pwm;
> + bool dpwm_mode;
> + bool phase_shift;
> + unsigned int short_detection_threshold;
> + unsigned int boost_current_limit;
> +};
> +
> +#endif
> --
> 1.9.1

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In reply to: Lee Jones: "Re: [PATCH v9 2/8] backlight: Add support Skyworks SKY81452 backlight driver"
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