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    Subject[PATCH v2 3/7] Adding Skyworks SKY81452 backlight driver
    Date
    v2:
    Added 'compatible' attribute in child drivers
    Added messages for exception or errors.

    ---
    drivers/video/backlight/Kconfig | 10 +
    drivers/video/backlight/Makefile | 1 +
    drivers/video/backlight/sky81452-backlight.c | 347 +++++++++++++++++++++++++++
    include/linux/sky81452-backlight.h | 47 ++++
    4 files changed, 405 insertions(+)
    create mode 100644 drivers/video/backlight/sky81452-backlight.c
    create mode 100644 include/linux/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..d292026
    --- /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@skyworksinc.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, 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>
    +
    +/* 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");
    +
    + 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:%d", ret);
    + return ret;
    + }
    + }
    +
    + ret = sky81452_bl_init_device(regmap, pdata);
    + if (IS_ERR_VALUE(ret)) {
    + dev_err(dev, "failed to initialize device:%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 backlight:%d", 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:%d", ret);
    + goto err;
    + }
    +
    + return ret;
    +err:
    + backlight_device_unregister(bd);
    + 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@skyworksinc.com>");
    +MODULE_LICENSE("GPL");
    +MODULE_VERSION("1.1");
    diff --git a/include/linux/sky81452-backlight.h b/include/linux/sky81452-backlight.h
    new file mode 100644
    index 0000000..b3635f9
    --- /dev/null
    +++ b/include/linux/sky81452-backlight.h
    @@ -0,0 +1,47 @@
    +/*
    + * sky81452.h SKY81452 backlight driver
    + *
    + * Copyright 2014 Skyworks Solutions Inc.
    + * Author : Gyungoh Yoo <jack.yoo@skyworksinc.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, 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/>.
    + */
    +
    +#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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