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// SPDX-License-Identifier: GPL-2.0-only
/*
* Backlight driver for Maxim MAX8925
*
* Copyright (C) 2009 Marvell International Ltd.
* Haojian Zhuang <haojian.zhuang@marvell.com>
*/
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/platform_device.h>
#include <linux/fb.h>
#include <linux/i2c.h>
#include <linux/backlight.h>
#include <linux/mfd/max8925.h>
#include <linux/slab.h>
#include <linux/module.h>
#define MAX_BRIGHTNESS (0xff)
#define MIN_BRIGHTNESS (0)
#define LWX_FREQ(x) (((x - 601) / 100) & 0x7)
struct max8925_backlight_data {
struct max8925_chip *chip;
int current_brightness;
int reg_mode_cntl;
int reg_cntl;
};
static int max8925_backlight_set(struct backlight_device *bl, int brightness)
{
struct max8925_backlight_data *data = bl_get_data(bl);
struct max8925_chip *chip = data->chip;
unsigned char value;
int ret;
if (brightness > MAX_BRIGHTNESS)
value = MAX_BRIGHTNESS;
else
value = brightness;
ret = max8925_reg_write(chip->i2c, data->reg_cntl, value);
if (ret < 0)
goto out;
if (!data->current_brightness && brightness)
/* enable WLED output */
ret = max8925_set_bits(chip->i2c, data->reg_mode_cntl, 1, 1);
else if (!brightness)
/* disable WLED output */
ret = max8925_set_bits(chip->i2c, data->reg_mode_cntl, 1, 0);
if (ret < 0)
goto out;
dev_dbg(chip->dev, "set brightness %d\n", value);
data->current_brightness = value;
return 0;
out:
dev_dbg(chip->dev, "set brightness %d failure with return value:%d\n",
value, ret);
return ret;
}
static int max8925_backlight_update_status(struct backlight_device *bl)
{
return max8925_backlight_set(bl, backlight_get_brightness(bl));
}
static int max8925_backlight_get_brightness(struct backlight_device *bl)
{
struct max8925_backlight_data *data = bl_get_data(bl);
struct max8925_chip *chip = data->chip;
int ret;
ret = max8925_reg_read(chip->i2c, data->reg_cntl);
if (ret < 0)
return -EINVAL;
data->current_brightness = ret;
dev_dbg(chip->dev, "get brightness %d\n", data->current_brightness);
return ret;
}
static const struct backlight_ops max8925_backlight_ops = {
.options = BL_CORE_SUSPENDRESUME,
.update_status = max8925_backlight_update_status,
.get_brightness = max8925_backlight_get_brightness,
};
static void max8925_backlight_dt_init(struct platform_device *pdev)
{
struct device_node *nproot = pdev->dev.parent->of_node, *np;
struct max8925_backlight_pdata *pdata;
u32 val;
if (!nproot || !IS_ENABLED(CONFIG_OF))
return;
pdata = devm_kzalloc(&pdev->dev,
sizeof(struct max8925_backlight_pdata),
GFP_KERNEL);
if (!pdata)
return;
np = of_get_child_by_name(nproot, "backlight");
if (!np) {
dev_err(&pdev->dev, "failed to find backlight node\n");
return;
}
if (!of_property_read_u32(np, "maxim,max8925-dual-string", &val))
pdata->dual_string = val;
of_node_put(np);
pdev->dev.platform_data = pdata;
}
static int max8925_backlight_probe(struct platform_device *pdev)
{
struct max8925_chip *chip = dev_get_drvdata(pdev->dev.parent);
struct max8925_backlight_pdata *pdata;
struct max8925_backlight_data *data;
struct backlight_device *bl;
struct backlight_properties props;
struct resource *res;
unsigned char value;
int ret = 0;
data = devm_kzalloc(&pdev->dev, sizeof(struct max8925_backlight_data),
GFP_KERNEL);
if (data == NULL)
return -ENOMEM;
res = platform_get_resource(pdev, IORESOURCE_REG, 0);
if (!res) {
dev_err(&pdev->dev, "No REG resource for mode control!\n");
return -ENXIO;
}
data->reg_mode_cntl = res->start;
res = platform_get_resource(pdev, IORESOURCE_REG, 1);
if (!res) {
dev_err(&pdev->dev, "No REG resource for control!\n");
return -ENXIO;
}
data->reg_cntl = res->start;
data->chip = chip;
data->current_brightness = 0;
memset(&props, 0, sizeof(struct backlight_properties));
props.type = BACKLIGHT_RAW;
props.max_brightness = MAX_BRIGHTNESS;
bl = devm_backlight_device_register(&pdev->dev, "max8925-backlight",
&pdev->dev, data,
&max8925_backlight_ops, &props);
if (IS_ERR(bl)) {
dev_err(&pdev->dev, "failed to register backlight\n");
return PTR_ERR(bl);
}
bl->props.brightness = MAX_BRIGHTNESS;
platform_set_drvdata(pdev, bl);
value = 0;
if (!pdev->dev.platform_data)
max8925_backlight_dt_init(pdev);
pdata = pdev->dev.platform_data;
if (pdata) {
if (pdata->lxw_scl)
value |= (1 << 7);
if (pdata->lxw_freq)
value |= (LWX_FREQ(pdata->lxw_freq) << 4);
if (pdata->dual_string)
value |= (1 << 1);
}
ret = max8925_set_bits(chip->i2c, data->reg_mode_cntl, 0xfe, value);
if (ret < 0)
return ret;
backlight_update_status(bl);
return 0;
}
static struct platform_driver max8925_backlight_driver = {
.driver = {
.name = "max8925-backlight",
},
.probe = max8925_backlight_probe,
};
module_platform_driver(max8925_backlight_driver);
MODULE_DESCRIPTION("Backlight Driver for Maxim MAX8925");
MODULE_AUTHOR("Haojian Zhuang <haojian.zhuang@marvell.com>");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:max8925-backlight");
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