u-boot/drivers/video/pwm_backlight.c
Tom Rini 83d290c56f SPDX: Convert all of our single license tags to Linux Kernel style
When U-Boot started using SPDX tags we were among the early adopters and
there weren't a lot of other examples to borrow from.  So we picked the
area of the file that usually had a full license text and replaced it
with an appropriate SPDX-License-Identifier: entry.  Since then, the
Linux Kernel has adopted SPDX tags and they place it as the very first
line in a file (except where shebangs are used, then it's second line)
and with slightly different comment styles than us.

In part due to community overlap, in part due to better tag visibility
and in part for other minor reasons, switch over to that style.

This commit changes all instances where we have a single declared
license in the tag as both the before and after are identical in tag
contents.  There's also a few places where I found we did not have a tag
and have introduced one.

Signed-off-by: Tom Rini <trini@konsulko.com>
2018-05-07 09:34:12 -04:00

134 lines
3.3 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (c) 2016 Google, Inc
* Written by Simon Glass <sjg@chromium.org>
*/
#include <common.h>
#include <dm.h>
#include <backlight.h>
#include <pwm.h>
#include <asm/gpio.h>
#include <power/regulator.h>
struct pwm_backlight_priv {
struct udevice *reg;
struct gpio_desc enable;
struct udevice *pwm;
uint channel;
uint period_ns;
uint default_level;
uint min_level;
uint max_level;
};
static int pwm_backlight_enable(struct udevice *dev)
{
struct pwm_backlight_priv *priv = dev_get_priv(dev);
struct dm_regulator_uclass_platdata *plat;
uint duty_cycle;
int ret;
if (priv->reg) {
plat = dev_get_uclass_platdata(priv->reg);
debug("%s: Enable '%s', regulator '%s'/'%s'\n", __func__,
dev->name, priv->reg->name, plat->name);
ret = regulator_set_enable(priv->reg, true);
if (ret) {
debug("%s: Cannot enable regulator for PWM '%s'\n",
__func__, dev->name);
return ret;
}
mdelay(120);
}
duty_cycle = priv->period_ns * (priv->default_level - priv->min_level) /
(priv->max_level - priv->min_level + 1);
ret = pwm_set_config(priv->pwm, priv->channel, priv->period_ns,
duty_cycle);
if (ret)
return ret;
ret = pwm_set_enable(priv->pwm, priv->channel, true);
if (ret)
return ret;
mdelay(10);
dm_gpio_set_value(&priv->enable, 1);
return 0;
}
static int pwm_backlight_ofdata_to_platdata(struct udevice *dev)
{
struct pwm_backlight_priv *priv = dev_get_priv(dev);
struct ofnode_phandle_args args;
int index, ret, count, len;
const u32 *cell;
debug("%s: start\n", __func__);
ret = uclass_get_device_by_phandle(UCLASS_REGULATOR, dev,
"power-supply", &priv->reg);
if (ret)
debug("%s: Cannot get power supply: ret=%d\n", __func__, ret);
ret = gpio_request_by_name(dev, "enable-gpios", 0, &priv->enable,
GPIOD_IS_OUT);
if (ret) {
debug("%s: Warning: cannot get enable GPIO: ret=%d\n",
__func__, ret);
if (ret != -ENOENT)
return ret;
}
ret = dev_read_phandle_with_args(dev, "pwms", "#pwm-cells", 0, 0,
&args);
if (ret) {
debug("%s: Cannot get PWM phandle: ret=%d\n", __func__, ret);
return ret;
}
ret = uclass_get_device_by_ofnode(UCLASS_PWM, args.node, &priv->pwm);
if (ret) {
debug("%s: Cannot get PWM: ret=%d\n", __func__, ret);
return ret;
}
priv->channel = args.args[0];
priv->period_ns = args.args[1];
index = dev_read_u32_default(dev, "default-brightness-level", 255);
cell = dev_read_prop(dev, "brightness-levels", &len);
count = len / sizeof(u32);
if (cell && count > index) {
priv->default_level = fdt32_to_cpu(cell[index]);
priv->max_level = fdt32_to_cpu(cell[count - 1]);
} else {
priv->default_level = index;
priv->max_level = 255;
}
debug("%s: done\n", __func__);
return 0;
}
static int pwm_backlight_probe(struct udevice *dev)
{
return 0;
}
static const struct backlight_ops pwm_backlight_ops = {
.enable = pwm_backlight_enable,
};
static const struct udevice_id pwm_backlight_ids[] = {
{ .compatible = "pwm-backlight" },
{ }
};
U_BOOT_DRIVER(pwm_backlight) = {
.name = "pwm_backlight",
.id = UCLASS_PANEL_BACKLIGHT,
.of_match = pwm_backlight_ids,
.ops = &pwm_backlight_ops,
.ofdata_to_platdata = pwm_backlight_ofdata_to_platdata,
.probe = pwm_backlight_probe,
.priv_auto_alloc_size = sizeof(struct pwm_backlight_priv),
};