354 lines
9.1 KiB
C
354 lines
9.1 KiB
C
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/*
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* sky81452-backlight.c SKY81452 backlight driver
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*
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* Copyright 2014 Skyworks Solutions Inc.
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* Author : Gyungoh Yoo <jack.yoo@skyworksinc.com>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2
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* as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, see <http://www.gnu.org/licenses/>.
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*/
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#include <linux/backlight.h>
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#include <linux/err.h>
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#include <linux/gpio.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/of.h>
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#include <linux/of_gpio.h>
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#include <linux/platform_device.h>
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#include <linux/regmap.h>
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#include <linux/platform_data/sky81452-backlight.h>
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#include <linux/slab.h>
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/* registers */
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#define SKY81452_REG0 0x00
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#define SKY81452_REG1 0x01
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#define SKY81452_REG2 0x02
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#define SKY81452_REG4 0x04
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#define SKY81452_REG5 0x05
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/* bit mask */
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#define SKY81452_CS 0xFF
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#define SKY81452_EN 0x3F
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#define SKY81452_IGPW 0x20
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#define SKY81452_PWMMD 0x10
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#define SKY81452_PHASE 0x08
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#define SKY81452_ILIM 0x04
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#define SKY81452_VSHRT 0x03
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#define SKY81452_OCP 0x80
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#define SKY81452_OTMP 0x40
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#define SKY81452_SHRT 0x3F
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#define SKY81452_OPN 0x3F
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#define SKY81452_DEFAULT_NAME "lcd-backlight"
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#define SKY81452_MAX_BRIGHTNESS (SKY81452_CS + 1)
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#define CTZ(b) __builtin_ctz(b)
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static int sky81452_bl_update_status(struct backlight_device *bd)
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{
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const struct sky81452_bl_platform_data *pdata =
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dev_get_platdata(bd->dev.parent);
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const unsigned int brightness = (unsigned int)bd->props.brightness;
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struct regmap *regmap = bl_get_data(bd);
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int ret;
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if (brightness > 0) {
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ret = regmap_write(regmap, SKY81452_REG0, brightness - 1);
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if (IS_ERR_VALUE(ret))
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return ret;
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return regmap_update_bits(regmap, SKY81452_REG1, SKY81452_EN,
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pdata->enable << CTZ(SKY81452_EN));
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}
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return regmap_update_bits(regmap, SKY81452_REG1, SKY81452_EN, 0);
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}
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static const struct backlight_ops sky81452_bl_ops = {
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.update_status = sky81452_bl_update_status,
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};
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static ssize_t sky81452_bl_store_enable(struct device *dev,
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struct device_attribute *attr, const char *buf, size_t count)
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{
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struct regmap *regmap = bl_get_data(to_backlight_device(dev));
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unsigned long value;
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int ret;
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ret = kstrtoul(buf, 16, &value);
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if (IS_ERR_VALUE(ret))
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return ret;
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ret = regmap_update_bits(regmap, SKY81452_REG1, SKY81452_EN,
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value << CTZ(SKY81452_EN));
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if (IS_ERR_VALUE(ret))
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return ret;
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return count;
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}
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static ssize_t sky81452_bl_show_open_short(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct regmap *regmap = bl_get_data(to_backlight_device(dev));
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unsigned int reg, value = 0;
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char tmp[3];
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int i, ret;
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reg = !strcmp(attr->attr.name, "open") ? SKY81452_REG5 : SKY81452_REG4;
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ret = regmap_read(regmap, reg, &value);
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if (IS_ERR_VALUE(ret))
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return ret;
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if (value & SKY81452_SHRT) {
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*buf = 0;
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for (i = 0; i < 6; i++) {
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if (value & 0x01) {
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sprintf(tmp, "%d ", i + 1);
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strcat(buf, tmp);
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}
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value >>= 1;
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}
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strcat(buf, "\n");
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} else {
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strcpy(buf, "none\n");
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}
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return strlen(buf);
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}
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static ssize_t sky81452_bl_show_fault(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct regmap *regmap = bl_get_data(to_backlight_device(dev));
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unsigned int value = 0;
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int ret;
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ret = regmap_read(regmap, SKY81452_REG4, &value);
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if (IS_ERR_VALUE(ret))
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return ret;
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*buf = 0;
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if (value & SKY81452_OCP)
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strcat(buf, "over-current ");
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if (value & SKY81452_OTMP)
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strcat(buf, "over-temperature");
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strcat(buf, "\n");
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return strlen(buf);
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}
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static DEVICE_ATTR(enable, S_IWGRP | S_IWUSR, NULL, sky81452_bl_store_enable);
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static DEVICE_ATTR(open, S_IRUGO, sky81452_bl_show_open_short, NULL);
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static DEVICE_ATTR(short, S_IRUGO, sky81452_bl_show_open_short, NULL);
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static DEVICE_ATTR(fault, S_IRUGO, sky81452_bl_show_fault, NULL);
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static struct attribute *sky81452_bl_attribute[] = {
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&dev_attr_enable.attr,
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&dev_attr_open.attr,
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&dev_attr_short.attr,
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&dev_attr_fault.attr,
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NULL
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};
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static const struct attribute_group sky81452_bl_attr_group = {
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.attrs = sky81452_bl_attribute,
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};
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#ifdef CONFIG_OF
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static struct sky81452_bl_platform_data *sky81452_bl_parse_dt(
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struct device *dev)
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{
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struct device_node *np = of_node_get(dev->of_node);
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struct sky81452_bl_platform_data *pdata;
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int num_entry;
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unsigned int sources[6];
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int ret;
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if (!np) {
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dev_err(dev, "backlight node not found.\n");
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return ERR_PTR(-ENODATA);
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}
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pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
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if (!pdata) {
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of_node_put(np);
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return ERR_PTR(-ENOMEM);
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}
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of_property_read_string(np, "name", &pdata->name);
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pdata->ignore_pwm = of_property_read_bool(np, "skyworks,ignore-pwm");
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pdata->dpwm_mode = of_property_read_bool(np, "skyworks,dpwm-mode");
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pdata->phase_shift = of_property_read_bool(np, "skyworks,phase-shift");
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pdata->gpio_enable = of_get_gpio(np, 0);
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ret = of_property_count_u32_elems(np, "led-sources");
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if (IS_ERR_VALUE(ret)) {
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pdata->enable = SKY81452_EN >> CTZ(SKY81452_EN);
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} else {
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num_entry = ret;
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if (num_entry > 6)
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num_entry = 6;
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ret = of_property_read_u32_array(np, "led-sources", sources,
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num_entry);
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if (IS_ERR_VALUE(ret)) {
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dev_err(dev, "led-sources node is invalid.\n");
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return ERR_PTR(-EINVAL);
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}
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pdata->enable = 0;
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while (--num_entry)
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pdata->enable |= (1 << sources[num_entry]);
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}
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ret = of_property_read_u32(np,
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"skyworks,short-detection-threshold-volt",
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&pdata->short_detection_threshold);
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if (IS_ERR_VALUE(ret))
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pdata->short_detection_threshold = 7;
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ret = of_property_read_u32(np, "skyworks,current-limit-mA",
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&pdata->boost_current_limit);
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if (IS_ERR_VALUE(ret))
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pdata->boost_current_limit = 2750;
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of_node_put(np);
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return pdata;
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}
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#else
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static struct sky81452_bl_platform_data *sky81452_bl_parse_dt(
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struct device *dev)
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{
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return ERR_PTR(-EINVAL);
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}
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#endif
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static int sky81452_bl_init_device(struct regmap *regmap,
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struct sky81452_bl_platform_data *pdata)
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{
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unsigned int value;
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value = pdata->ignore_pwm ? SKY81452_IGPW : 0;
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value |= pdata->dpwm_mode ? SKY81452_PWMMD : 0;
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value |= pdata->phase_shift ? 0 : SKY81452_PHASE;
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if (pdata->boost_current_limit == 2300)
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value |= SKY81452_ILIM;
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else if (pdata->boost_current_limit != 2750)
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return -EINVAL;
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if (pdata->short_detection_threshold < 4 ||
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pdata->short_detection_threshold > 7)
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return -EINVAL;
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value |= (7 - pdata->short_detection_threshold) << CTZ(SKY81452_VSHRT);
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return regmap_write(regmap, SKY81452_REG2, value);
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}
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static int sky81452_bl_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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struct regmap *regmap = dev_get_drvdata(dev->parent);
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struct sky81452_bl_platform_data *pdata = dev_get_platdata(dev);
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struct backlight_device *bd;
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struct backlight_properties props;
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const char *name;
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int ret;
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if (!pdata) {
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pdata = sky81452_bl_parse_dt(dev);
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if (IS_ERR(pdata))
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return PTR_ERR(pdata);
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}
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if (gpio_is_valid(pdata->gpio_enable)) {
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ret = devm_gpio_request_one(dev, pdata->gpio_enable,
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GPIOF_OUT_INIT_HIGH, "sky81452-en");
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if (IS_ERR_VALUE(ret)) {
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dev_err(dev, "failed to request GPIO. err=%d\n", ret);
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return ret;
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}
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}
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ret = sky81452_bl_init_device(regmap, pdata);
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if (IS_ERR_VALUE(ret)) {
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dev_err(dev, "failed to initialize. err=%d\n", ret);
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return ret;
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}
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memset(&props, 0, sizeof(props));
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props.max_brightness = SKY81452_MAX_BRIGHTNESS,
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name = pdata->name ? pdata->name : SKY81452_DEFAULT_NAME;
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bd = devm_backlight_device_register(dev, name, dev, regmap,
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&sky81452_bl_ops, &props);
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if (IS_ERR(bd)) {
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dev_err(dev, "failed to register. err=%ld\n", PTR_ERR(bd));
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return PTR_ERR(bd);
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}
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platform_set_drvdata(pdev, bd);
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ret = sysfs_create_group(&bd->dev.kobj, &sky81452_bl_attr_group);
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if (IS_ERR_VALUE(ret)) {
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dev_err(dev, "failed to create attribute. err=%d\n", ret);
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return ret;
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}
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return ret;
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}
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static int sky81452_bl_remove(struct platform_device *pdev)
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{
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const struct sky81452_bl_platform_data *pdata =
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dev_get_platdata(&pdev->dev);
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struct backlight_device *bd = platform_get_drvdata(pdev);
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sysfs_remove_group(&bd->dev.kobj, &sky81452_bl_attr_group);
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bd->props.power = FB_BLANK_UNBLANK;
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bd->props.brightness = 0;
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backlight_update_status(bd);
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if (gpio_is_valid(pdata->gpio_enable))
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gpio_set_value_cansleep(pdata->gpio_enable, 0);
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return 0;
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}
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#ifdef CONFIG_OF
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static const struct of_device_id sky81452_bl_of_match[] = {
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{ .compatible = "skyworks,sky81452-backlight", },
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{ }
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};
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MODULE_DEVICE_TABLE(of, sky81452_bl_of_match);
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#endif
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static struct platform_driver sky81452_bl_driver = {
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.driver = {
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.name = "sky81452-backlight",
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.of_match_table = of_match_ptr(sky81452_bl_of_match),
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},
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.probe = sky81452_bl_probe,
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.remove = sky81452_bl_remove,
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};
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module_platform_driver(sky81452_bl_driver);
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MODULE_DESCRIPTION("Skyworks SKY81452 backlight driver");
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MODULE_AUTHOR("Gyungoh Yoo <jack.yoo@skyworksinc.com>");
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MODULE_LICENSE("GPL v2");
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