92598bdbae
This cannot actually fail, but check the value anyway to keep coverity happy. Signed-off-by: Simon Glass <sjg@chromium.org> Reported-by: Coverity (CID: 316351)
280 lines
6.7 KiB
C
280 lines
6.7 KiB
C
// SPDX-License-Identifier: GPL-2.0+
|
|
/*
|
|
* Copyright (c) 2016 Google, Inc
|
|
* Written by Simon Glass <sjg@chromium.org>
|
|
*/
|
|
|
|
#define LOG_CATEGORY UCLASS_PANEL_BACKLIGHT
|
|
|
|
#include <common.h>
|
|
#include <dm.h>
|
|
#include <backlight.h>
|
|
#include <log.h>
|
|
#include <malloc.h>
|
|
#include <pwm.h>
|
|
#include <asm/gpio.h>
|
|
#include <linux/delay.h>
|
|
#include <power/regulator.h>
|
|
|
|
/**
|
|
* Private information for the PWM backlight
|
|
*
|
|
* If @num_levels is 0 then the levels are simple values with the backlight
|
|
* value going between the minimum (default 0) and the maximum (default 255).
|
|
* Otherwise the levels are an index into @levels (0..n-1).
|
|
*
|
|
* @reg: Regulator to enable to turn the backlight on (NULL if none)
|
|
* @enable, GPIO to set to enable the backlight (can be missing)
|
|
* @pwm: PWM to use to change the backlight brightness
|
|
* @channel: PWM channel to use
|
|
* @period_ns: Period of the backlight in nanoseconds
|
|
* @levels: Levels for the backlight, or NULL if not using indexed levels
|
|
* @num_levels: Number of levels
|
|
* @cur_level: Current level for the backlight (index or value)
|
|
* @default_level: Default level for the backlight (index or value)
|
|
* @min_level: Minimum level of the backlight (full off)
|
|
* @max_level: Maximum level of the backlight (full on)
|
|
* @enabled: true if backlight is enabled
|
|
*/
|
|
struct pwm_backlight_priv {
|
|
struct udevice *reg;
|
|
struct gpio_desc enable;
|
|
struct udevice *pwm;
|
|
uint channel;
|
|
uint period_ns;
|
|
/*
|
|
* the polarity of one PWM
|
|
* 0: normal polarity
|
|
* 1: inverted polarity
|
|
*/
|
|
bool polarity;
|
|
u32 *levels;
|
|
int num_levels;
|
|
uint default_level;
|
|
int cur_level;
|
|
uint min_level;
|
|
uint max_level;
|
|
bool enabled;
|
|
};
|
|
|
|
static int set_pwm(struct pwm_backlight_priv *priv)
|
|
{
|
|
uint duty_cycle;
|
|
int ret;
|
|
|
|
if (priv->period_ns) {
|
|
duty_cycle = priv->period_ns * (priv->cur_level - priv->min_level) /
|
|
(priv->max_level - priv->min_level);
|
|
ret = pwm_set_config(priv->pwm, priv->channel, priv->period_ns,
|
|
duty_cycle);
|
|
} else {
|
|
/* PWM driver will internally scale these like the above. */
|
|
ret = pwm_set_config(priv->pwm, priv->channel,
|
|
priv->max_level - priv->min_level,
|
|
priv->cur_level - priv->min_level);
|
|
}
|
|
if (ret)
|
|
return log_ret(ret);
|
|
|
|
ret = pwm_set_invert(priv->pwm, priv->channel, priv->polarity);
|
|
if (ret == -ENOSYS && !priv->polarity)
|
|
ret = 0;
|
|
|
|
return log_ret(ret);
|
|
}
|
|
|
|
static int enable_sequence(struct udevice *dev, int seq)
|
|
{
|
|
struct pwm_backlight_priv *priv = dev_get_priv(dev);
|
|
int ret;
|
|
|
|
switch (seq) {
|
|
case 0:
|
|
if (priv->reg) {
|
|
__maybe_unused struct dm_regulator_uclass_plat
|
|
*plat;
|
|
|
|
plat = dev_get_uclass_plat(priv->reg);
|
|
log_debug("Enable '%s', regulator '%s'/'%s'\n",
|
|
dev->name, priv->reg->name, plat->name);
|
|
ret = regulator_set_enable(priv->reg, true);
|
|
if (ret) {
|
|
log_debug("Cannot enable regulator for PWM '%s'\n",
|
|
dev->name);
|
|
return log_ret(ret);
|
|
}
|
|
mdelay(120);
|
|
}
|
|
break;
|
|
case 1:
|
|
mdelay(10);
|
|
dm_gpio_set_value(&priv->enable, 1);
|
|
break;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int pwm_backlight_enable(struct udevice *dev)
|
|
{
|
|
struct pwm_backlight_priv *priv = dev_get_priv(dev);
|
|
int ret;
|
|
|
|
ret = enable_sequence(dev, 0);
|
|
if (ret)
|
|
return log_ret(ret);
|
|
ret = set_pwm(priv);
|
|
if (ret)
|
|
return log_ret(ret);
|
|
ret = pwm_set_enable(priv->pwm, priv->channel, true);
|
|
if (ret)
|
|
return log_ret(ret);
|
|
ret = enable_sequence(dev, 1);
|
|
if (ret)
|
|
return log_ret(ret);
|
|
priv->enabled = true;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int pwm_backlight_set_brightness(struct udevice *dev, int percent)
|
|
{
|
|
struct pwm_backlight_priv *priv = dev_get_priv(dev);
|
|
bool disable = false;
|
|
int level;
|
|
int ret;
|
|
|
|
if (!priv->enabled) {
|
|
ret = enable_sequence(dev, 0);
|
|
if (ret)
|
|
return log_ret(ret);
|
|
}
|
|
if (percent == BACKLIGHT_OFF) {
|
|
disable = true;
|
|
percent = 0;
|
|
}
|
|
if (percent == BACKLIGHT_DEFAULT) {
|
|
level = priv->default_level;
|
|
} else {
|
|
if (priv->levels) {
|
|
level = priv->levels[percent * (priv->num_levels - 1)
|
|
/ 100];
|
|
} else {
|
|
level = priv->min_level +
|
|
(priv->max_level - priv->min_level) *
|
|
percent / 100;
|
|
}
|
|
}
|
|
priv->cur_level = level;
|
|
|
|
ret = set_pwm(priv);
|
|
if (ret)
|
|
return log_ret(ret);
|
|
if (!priv->enabled) {
|
|
ret = enable_sequence(dev, 1);
|
|
if (ret)
|
|
return log_ret(ret);
|
|
priv->enabled = true;
|
|
}
|
|
if (disable) {
|
|
dm_gpio_set_value(&priv->enable, 0);
|
|
if (priv->reg) {
|
|
ret = regulator_set_enable(priv->reg, false);
|
|
if (ret)
|
|
return log_ret(ret);
|
|
}
|
|
priv->enabled = false;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int pwm_backlight_of_to_plat(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;
|
|
|
|
log_debug("start\n");
|
|
ret = uclass_get_device_by_phandle(UCLASS_REGULATOR, dev,
|
|
"power-supply", &priv->reg);
|
|
if (ret)
|
|
log_debug("Cannot get power supply: ret=%d\n", ret);
|
|
ret = gpio_request_by_name(dev, "enable-gpios", 0, &priv->enable,
|
|
GPIOD_IS_OUT);
|
|
if (ret) {
|
|
log_debug("Warning: cannot get enable GPIO: ret=%d\n", ret);
|
|
if (ret != -ENOENT)
|
|
return log_ret(ret);
|
|
}
|
|
ret = dev_read_phandle_with_args(dev, "pwms", "#pwm-cells", 0, 0,
|
|
&args);
|
|
if (ret) {
|
|
log_debug("Cannot get PWM phandle: ret=%d\n", ret);
|
|
return log_ret(ret);
|
|
}
|
|
|
|
ret = uclass_get_device_by_ofnode(UCLASS_PWM, args.node, &priv->pwm);
|
|
if (ret) {
|
|
log_debug("Cannot get PWM: ret=%d\n", ret);
|
|
return log_ret(ret);
|
|
}
|
|
if (args.args_count < 1)
|
|
return log_msg_ret("Not enough arguments to pwm\n", -EINVAL);
|
|
priv->channel = args.args[0];
|
|
if (args.args_count > 1)
|
|
priv->period_ns = args.args[1];
|
|
if (args.args_count > 2)
|
|
priv->polarity = args.args[2];
|
|
|
|
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->levels = malloc(len);
|
|
if (!priv->levels)
|
|
return log_ret(-ENOMEM);
|
|
ret = dev_read_u32_array(dev, "brightness-levels", priv->levels,
|
|
count);
|
|
if (ret)
|
|
return log_msg_ret("levels", ret);
|
|
priv->num_levels = count;
|
|
priv->default_level = priv->levels[index];
|
|
priv->max_level = priv->levels[count - 1];
|
|
} else {
|
|
priv->default_level = index;
|
|
priv->max_level = 255;
|
|
}
|
|
priv->cur_level = priv->default_level;
|
|
log_debug("done\n");
|
|
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int pwm_backlight_probe(struct udevice *dev)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
static const struct backlight_ops pwm_backlight_ops = {
|
|
.enable = pwm_backlight_enable,
|
|
.set_brightness = pwm_backlight_set_brightness,
|
|
};
|
|
|
|
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,
|
|
.of_to_plat = pwm_backlight_of_to_plat,
|
|
.probe = pwm_backlight_probe,
|
|
.priv_auto = sizeof(struct pwm_backlight_priv),
|
|
};
|