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// SPDX-License-Identifier: GPL-2.0-only
/*
* Backlight driver for Wolfson Microelectronics WM831x PMICs
*
* Copyright 2009 Wolfson Microelectonics plc
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/module.h>
#include <linux/fb.h>
#include <linux/backlight.h>
#include <linux/slab.h>
#include <linux/mfd/wm831x/core.h>
#include <linux/mfd/wm831x/pdata.h>
#include <linux/mfd/wm831x/regulator.h>
struct wm831x_backlight_data {
struct wm831x *wm831x;
int isink_reg;
int current_brightness;
};
static int wm831x_backlight_set(struct backlight_device *bl, int brightness)
{
struct wm831x_backlight_data *data = bl_get_data(bl);
struct wm831x *wm831x = data->wm831x;
int power_up = !data->current_brightness && brightness;
int power_down = data->current_brightness && !brightness;
int ret;
if (power_up) {
/* Enable the ISINK */
ret = wm831x_set_bits(wm831x, data->isink_reg,
WM831X_CS1_ENA, WM831X_CS1_ENA);
if (ret < 0)
goto err;
/* Enable the DC-DC */
ret = wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE,
WM831X_DC4_ENA, WM831X_DC4_ENA);
if (ret < 0)
goto err;
}
if (power_down) {
/* DCDC first */
ret = wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE,
WM831X_DC4_ENA, 0);
if (ret < 0)
goto err;
/* ISINK */
ret = wm831x_set_bits(wm831x, data->isink_reg,
WM831X_CS1_DRIVE | WM831X_CS1_ENA, 0);
if (ret < 0)
goto err;
}
/* Set the new brightness */
ret = wm831x_set_bits(wm831x, data->isink_reg,
WM831X_CS1_ISEL_MASK, brightness);
if (ret < 0)
goto err;
if (power_up) {
/* Drive current through the ISINK */
ret = wm831x_set_bits(wm831x, data->isink_reg,
WM831X_CS1_DRIVE, WM831X_CS1_DRIVE);
if (ret < 0)
return ret;
}
data->current_brightness = brightness;
return 0;
err:
/* If we were in the middle of a power transition always shut down
* for safety.
*/
if (power_up || power_down) {
wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE, WM831X_DC4_ENA, 0);
wm831x_set_bits(wm831x, data->isink_reg, WM831X_CS1_ENA, 0);
}
return ret;
}
static int wm831x_backlight_update_status(struct backlight_device *bl)
{
return wm831x_backlight_set(bl, backlight_get_brightness(bl));
}
static int wm831x_backlight_get_brightness(struct backlight_device *bl)
{
struct wm831x_backlight_data *data = bl_get_data(bl);
return data->current_brightness;
}
static const struct backlight_ops wm831x_backlight_ops = {
.options = BL_CORE_SUSPENDRESUME,
.update_status = wm831x_backlight_update_status,
.get_brightness = wm831x_backlight_get_brightness,
};
static int wm831x_backlight_probe(struct platform_device *pdev)
{
struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent);
struct wm831x_pdata *wm831x_pdata = dev_get_platdata(pdev->dev.parent);
struct wm831x_backlight_pdata *pdata;
struct wm831x_backlight_data *data;
struct backlight_device *bl;
struct backlight_properties props;
int ret, i, max_isel, isink_reg, dcdc_cfg;
/* We need platform data */
if (wm831x_pdata)
pdata = wm831x_pdata->backlight;
else
pdata = NULL;
if (!pdata) {
dev_err(&pdev->dev, "No platform data supplied\n");
return -EINVAL;
}
/* Figure out the maximum current we can use */
for (i = 0; i < WM831X_ISINK_MAX_ISEL; i++) {
if (wm831x_isinkv_values[i] > pdata->max_uA)
break;
}
if (i == 0) {
dev_err(&pdev->dev, "Invalid max_uA: %duA\n", pdata->max_uA);
return -EINVAL;
}
max_isel = i - 1;
if (pdata->max_uA != wm831x_isinkv_values[max_isel])
dev_warn(&pdev->dev,
"Maximum current is %duA not %duA as requested\n",
wm831x_isinkv_values[max_isel], pdata->max_uA);
switch (pdata->isink) {
case 1:
isink_reg = WM831X_CURRENT_SINK_1;
dcdc_cfg = 0;
break;
case 2:
isink_reg = WM831X_CURRENT_SINK_2;
dcdc_cfg = WM831X_DC4_FBSRC;
break;
default:
dev_err(&pdev->dev, "Invalid ISINK %d\n", pdata->isink);
return -EINVAL;
}
/* Configure the ISINK to use for feedback */
ret = wm831x_reg_unlock(wm831x);
if (ret < 0)
return ret;
ret = wm831x_set_bits(wm831x, WM831X_DC4_CONTROL, WM831X_DC4_FBSRC,
dcdc_cfg);
wm831x_reg_lock(wm831x);
if (ret < 0)
return ret;
data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
if (data == NULL)
return -ENOMEM;
data->wm831x = wm831x;
data->current_brightness = 0;
data->isink_reg = isink_reg;
memset(&props, 0, sizeof(props));
props.type = BACKLIGHT_RAW;
props.max_brightness = max_isel;
bl = devm_backlight_device_register(&pdev->dev, "wm831x", &pdev->dev,
data, &wm831x_backlight_ops, &props);
if (IS_ERR(bl)) {
dev_err(&pdev->dev, "failed to register backlight\n");
return PTR_ERR(bl);
}
bl->props.brightness = max_isel;
platform_set_drvdata(pdev, bl);
/* Disable the DCDC if it was started so we can bootstrap */
wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE, WM831X_DC4_ENA, 0);
backlight_update_status(bl);
return 0;
}
static struct platform_driver wm831x_backlight_driver = {
.driver = {
.name = "wm831x-backlight",
},
.probe = wm831x_backlight_probe,
};
module_platform_driver(wm831x_backlight_driver);
MODULE_DESCRIPTION("Backlight Driver for WM831x PMICs");
MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:wm831x-backlight");
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