#include <linux/backlight.h>
#include <linux/err.h>
#include <linux/gpio/consumer.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/slab.h>
#define SKY81452_REG0 0x00
#define SKY81452_REG1 0x01
#define SKY81452_REG2 0x02
#define SKY81452_REG4 0x04
#define SKY81452_REG5 0x05
#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)
struct sky81452_bl_platform_data {
const char *name;
struct gpio_desc *gpiod_enable;
unsigned int enable;
bool ignore_pwm;
bool dpwm_mode;
bool phase_shift;
unsigned int short_detection_threshold;
unsigned int boost_current_limit;
};
#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 (ret < 0)
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 const struct backlight_ops sky81452_bl_ops = {
.update_status = sky81452_bl_update_status,
};
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 (ret < 0)
return ret;
ret = regmap_update_bits(regmap, SKY81452_REG1, SKY81452_EN,
value << CTZ(SKY81452_EN));
if (ret < 0)
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 (ret < 0)
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 (ret < 0)
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 = dev->of_node;
struct sky81452_bl_platform_data *pdata;
int num_entry;
unsigned int sources[6];
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)
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->gpiod_enable = devm_gpiod_get_optional(dev, NULL, GPIOD_OUT_HIGH);
ret = of_property_count_u32_elems(np, "led-sources");
if (ret < 0) {
pdata->enable = SKY81452_EN >> CTZ(SKY81452_EN);
} else {
num_entry = ret;
if (num_entry > 6)
num_entry = 6;
ret = of_property_read_u32_array(np, "led-sources", sources,
num_entry);
if (ret < 0) {
dev_err(dev, "led-sources node is invalid.\n");
return ERR_PTR(-EINVAL);
}
pdata->enable = 0;
while (--num_entry)
pdata->enable |= (1 << sources[num_entry]);
}
ret = of_property_read_u32(np,
"skyworks,short-detection-threshold-volt",
&pdata->short_detection_threshold);
if (ret < 0)
pdata->short_detection_threshold = 7;
ret = of_property_read_u32(np, "skyworks,current-limit-mA",
&pdata->boost_current_limit);
if (ret < 0)
pdata->boost_current_limit = 2750;
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;
struct backlight_device *bd;
struct backlight_properties props;
const char *name;
int ret;
pdata = sky81452_bl_parse_dt(dev);
if (IS_ERR(pdata))
return PTR_ERR(pdata);
ret = sky81452_bl_init_device(regmap, pdata);
if (ret < 0) {
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 (ret < 0) {
dev_err(dev, "failed to create attribute. err=%d\n", ret);
return ret;
}
return ret;
}
static void 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 = BACKLIGHT_POWER_ON;
bd->props.brightness = 0;
backlight_update_status(bd);
if (pdata->gpiod_enable)
gpiod_set_value_cansleep(pdata->gpiod_enable, 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 v2");
