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// SPDX-License-Identifier: GPL-2.0-only
#include <dt-bindings/leds/rt4831-backlight.h>
#include <linux/backlight.h>
#include <linux/bitops.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/property.h>
#include <linux/regmap.h>
#define RT4831_REG_BLCFG 0x02
#define RT4831_REG_BLDIML 0x04
#define RT4831_REG_ENABLE 0x08
#define RT4831_REG_BLOPT2 0x11
#define RT4831_BLMAX_BRIGHTNESS 2048
#define RT4831_BLOVP_MASK GENMASK(7, 5)
#define RT4831_BLOVP_SHIFT 5
#define RT4831_BLPWMEN_MASK BIT(0)
#define RT4831_BLEN_MASK BIT(4)
#define RT4831_BLCH_MASK GENMASK(3, 0)
#define RT4831_BLDIML_MASK GENMASK(2, 0)
#define RT4831_BLDIMH_MASK GENMASK(10, 3)
#define RT4831_BLDIMH_SHIFT 3
#define RT4831_BLOCP_MASK GENMASK(1, 0)
#define RT4831_BLOCP_MINUA 900000
#define RT4831_BLOCP_MAXUA 1800000
#define RT4831_BLOCP_STEPUA 300000
struct rt4831_priv {
struct device *dev;
struct regmap *regmap;
struct backlight_device *bl;
};
static int rt4831_bl_update_status(struct backlight_device *bl_dev)
{
struct rt4831_priv *priv = bl_get_data(bl_dev);
int brightness = backlight_get_brightness(bl_dev);
unsigned int enable = brightness ? RT4831_BLEN_MASK : 0;
u8 v[2];
int ret;
if (brightness) {
v[0] = (brightness - 1) & RT4831_BLDIML_MASK;
v[1] = ((brightness - 1) & RT4831_BLDIMH_MASK) >> RT4831_BLDIMH_SHIFT;
ret = regmap_raw_write(priv->regmap, RT4831_REG_BLDIML, v, sizeof(v));
if (ret)
return ret;
}
return regmap_update_bits(priv->regmap, RT4831_REG_ENABLE, RT4831_BLEN_MASK, enable);
}
static int rt4831_bl_get_brightness(struct backlight_device *bl_dev)
{
struct rt4831_priv *priv = bl_get_data(bl_dev);
unsigned int val;
u8 v[2];
int ret;
ret = regmap_read(priv->regmap, RT4831_REG_ENABLE, &val);
if (ret)
return ret;
if (!(val & RT4831_BLEN_MASK))
return 0;
ret = regmap_raw_read(priv->regmap, RT4831_REG_BLDIML, v, sizeof(v));
if (ret)
return ret;
ret = (v[1] << RT4831_BLDIMH_SHIFT) + (v[0] & RT4831_BLDIML_MASK) + 1;
return ret;
}
static const struct backlight_ops rt4831_bl_ops = {
.options = BL_CORE_SUSPENDRESUME,
.update_status = rt4831_bl_update_status,
.get_brightness = rt4831_bl_get_brightness,
};
static int rt4831_parse_backlight_properties(struct rt4831_priv *priv,
struct backlight_properties *bl_props)
{
struct device *dev = priv->dev;
u8 propval;
u32 brightness, ocp_uA;
unsigned int val = 0;
int ret;
/* common properties */
ret = device_property_read_u32(dev, "max-brightness", &brightness);
if (ret)
brightness = RT4831_BLMAX_BRIGHTNESS;
bl_props->max_brightness = min_t(u32, brightness, RT4831_BLMAX_BRIGHTNESS);
ret = device_property_read_u32(dev, "default-brightness", &brightness);
if (ret)
brightness = bl_props->max_brightness;
bl_props->brightness = min_t(u32, brightness, bl_props->max_brightness);
/* vendor properties */
if (device_property_read_bool(dev, "richtek,pwm-enable"))
val = RT4831_BLPWMEN_MASK;
ret = regmap_update_bits(priv->regmap, RT4831_REG_BLCFG, RT4831_BLPWMEN_MASK, val);
if (ret)
return ret;
ret = device_property_read_u8(dev, "richtek,bled-ovp-sel", &propval);
if (ret)
propval = RT4831_BLOVPLVL_21V;
propval = min_t(u8, propval, RT4831_BLOVPLVL_29V);
ret = regmap_update_bits(priv->regmap, RT4831_REG_BLCFG, RT4831_BLOVP_MASK,
propval << RT4831_BLOVP_SHIFT);
if (ret)
return ret;
/*
* This OCP level is used to protect and limit the inductor current.
* If inductor peak current reach the level, low-side MOSFET will be
* turned off. Meanwhile, the output channel current may be limited.
* To match the configured channel current, the inductor chosen must
* be higher than the OCP level.
*
* Not like the OVP level, the default 21V can be used in the most
* application. But if the chosen OCP level is smaller than needed,
* it will also affect the backlight channel output current to be
* smaller than the register setting.
*/
ret = device_property_read_u32(dev, "richtek,bled-ocp-microamp",
&ocp_uA);
if (!ret) {
ocp_uA = clamp_val(ocp_uA, RT4831_BLOCP_MINUA,
RT4831_BLOCP_MAXUA);
val = DIV_ROUND_UP(ocp_uA - RT4831_BLOCP_MINUA,
RT4831_BLOCP_STEPUA);
ret = regmap_update_bits(priv->regmap, RT4831_REG_BLOPT2,
RT4831_BLOCP_MASK, val);
if (ret)
return ret;
}
ret = device_property_read_u8(dev, "richtek,channel-use", &propval);
if (ret) {
dev_err(dev, "richtek,channel-use DT property missing\n");
return ret;
}
if (!(propval & RT4831_BLCH_MASK)) {
dev_err(dev, "No channel specified\n");
return -EINVAL;
}
return regmap_update_bits(priv->regmap, RT4831_REG_ENABLE, RT4831_BLCH_MASK, propval);
}
static int rt4831_bl_probe(struct platform_device *pdev)
{
struct rt4831_priv *priv;
struct backlight_properties bl_props = { .type = BACKLIGHT_RAW,
.scale = BACKLIGHT_SCALE_LINEAR };
int ret;
priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;
priv->dev = &pdev->dev;
priv->regmap = dev_get_regmap(pdev->dev.parent, NULL);
if (!priv->regmap) {
dev_err(&pdev->dev, "Failed to init regmap\n");
return -ENODEV;
}
ret = rt4831_parse_backlight_properties(priv, &bl_props);
if (ret) {
dev_err(&pdev->dev, "Failed to parse backlight properties\n");
return ret;
}
priv->bl = devm_backlight_device_register(&pdev->dev, pdev->name, &pdev->dev, priv,
&rt4831_bl_ops, &bl_props);
if (IS_ERR(priv->bl)) {
dev_err(&pdev->dev, "Failed to register backlight\n");
return PTR_ERR(priv->bl);
}
backlight_update_status(priv->bl);
platform_set_drvdata(pdev, priv);
return 0;
}
static void rt4831_bl_remove(struct platform_device *pdev)
{
struct rt4831_priv *priv = platform_get_drvdata(pdev);
struct backlight_device *bl_dev = priv->bl;
bl_dev->props.brightness = 0;
backlight_update_status(priv->bl);
}
static const struct of_device_id __maybe_unused rt4831_bl_of_match[] = {
{ .compatible = "richtek,rt4831-backlight", },
{}
};
MODULE_DEVICE_TABLE(of, rt4831_bl_of_match);
static struct platform_driver rt4831_bl_driver = {
.driver = {
.name = "rt4831-backlight",
.of_match_table = rt4831_bl_of_match,
},
.probe = rt4831_bl_probe,
.remove_new = rt4831_bl_remove,
};
module_platform_driver(rt4831_bl_driver);
MODULE_AUTHOR("ChiYuan Huang <cy_huang@richtek.com>");
MODULE_DESCRIPTION("Richtek RT4831 Backlight Driver");
MODULE_LICENSE("GPL v2");
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