mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-25 02:18:23 +07:00
937222c4dd
commit 257462dbf3
("pwm-backlight: switch to gpiod interface")
introduced a regression leading to acquiring a bogus GPIO-0 when
configured from DT without an 'enable-gpios' property.
The driver will happily accept the 0 initialized 'enable_gpio' member
of the struct platform_pwm_backlight_data as valid gpio number, and
request this GPIO as enable pin. In case of multiple driver instances,
the second will fail to register with the error message:
pwm-backlight backlight1.23: failed to request GPIO#0: -16
Fix this by setting enable_gpio in the pdata struct to -EINVAL.
Signed-off-by: Lothar Waßmann <LW@KARO-electronics.de>
Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
407 lines
9.5 KiB
C
407 lines
9.5 KiB
C
/*
|
|
* linux/drivers/video/backlight/pwm_bl.c
|
|
*
|
|
* simple PWM based backlight control, board code has to setup
|
|
* 1) pin configuration so PWM waveforms can output
|
|
* 2) platform_data being correctly configured
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License version 2 as
|
|
* published by the Free Software Foundation.
|
|
*/
|
|
|
|
#include <linux/gpio/consumer.h>
|
|
#include <linux/gpio.h>
|
|
#include <linux/module.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/init.h>
|
|
#include <linux/platform_device.h>
|
|
#include <linux/fb.h>
|
|
#include <linux/backlight.h>
|
|
#include <linux/err.h>
|
|
#include <linux/pwm.h>
|
|
#include <linux/pwm_backlight.h>
|
|
#include <linux/regulator/consumer.h>
|
|
#include <linux/slab.h>
|
|
|
|
struct pwm_bl_data {
|
|
struct pwm_device *pwm;
|
|
struct device *dev;
|
|
unsigned int period;
|
|
unsigned int lth_brightness;
|
|
unsigned int *levels;
|
|
bool enabled;
|
|
struct regulator *power_supply;
|
|
struct gpio_desc *enable_gpio;
|
|
unsigned int scale;
|
|
int (*notify)(struct device *,
|
|
int brightness);
|
|
void (*notify_after)(struct device *,
|
|
int brightness);
|
|
int (*check_fb)(struct device *, struct fb_info *);
|
|
void (*exit)(struct device *);
|
|
};
|
|
|
|
static void pwm_backlight_power_on(struct pwm_bl_data *pb, int brightness)
|
|
{
|
|
int err;
|
|
|
|
if (pb->enabled)
|
|
return;
|
|
|
|
err = regulator_enable(pb->power_supply);
|
|
if (err < 0)
|
|
dev_err(pb->dev, "failed to enable power supply\n");
|
|
|
|
if (pb->enable_gpio)
|
|
gpiod_set_value(pb->enable_gpio, 1);
|
|
|
|
pwm_enable(pb->pwm);
|
|
pb->enabled = true;
|
|
}
|
|
|
|
static void pwm_backlight_power_off(struct pwm_bl_data *pb)
|
|
{
|
|
if (!pb->enabled)
|
|
return;
|
|
|
|
pwm_config(pb->pwm, 0, pb->period);
|
|
pwm_disable(pb->pwm);
|
|
|
|
if (pb->enable_gpio)
|
|
gpiod_set_value(pb->enable_gpio, 0);
|
|
|
|
regulator_disable(pb->power_supply);
|
|
pb->enabled = false;
|
|
}
|
|
|
|
static int compute_duty_cycle(struct pwm_bl_data *pb, int brightness)
|
|
{
|
|
unsigned int lth = pb->lth_brightness;
|
|
int duty_cycle;
|
|
|
|
if (pb->levels)
|
|
duty_cycle = pb->levels[brightness];
|
|
else
|
|
duty_cycle = brightness;
|
|
|
|
return (duty_cycle * (pb->period - lth) / pb->scale) + lth;
|
|
}
|
|
|
|
static int pwm_backlight_update_status(struct backlight_device *bl)
|
|
{
|
|
struct pwm_bl_data *pb = bl_get_data(bl);
|
|
int brightness = bl->props.brightness;
|
|
int duty_cycle;
|
|
|
|
if (bl->props.power != FB_BLANK_UNBLANK ||
|
|
bl->props.fb_blank != FB_BLANK_UNBLANK ||
|
|
bl->props.state & BL_CORE_FBBLANK)
|
|
brightness = 0;
|
|
|
|
if (pb->notify)
|
|
brightness = pb->notify(pb->dev, brightness);
|
|
|
|
if (brightness > 0) {
|
|
duty_cycle = compute_duty_cycle(pb, brightness);
|
|
pwm_config(pb->pwm, duty_cycle, pb->period);
|
|
pwm_backlight_power_on(pb, brightness);
|
|
} else
|
|
pwm_backlight_power_off(pb);
|
|
|
|
if (pb->notify_after)
|
|
pb->notify_after(pb->dev, brightness);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int pwm_backlight_check_fb(struct backlight_device *bl,
|
|
struct fb_info *info)
|
|
{
|
|
struct pwm_bl_data *pb = bl_get_data(bl);
|
|
|
|
return !pb->check_fb || pb->check_fb(pb->dev, info);
|
|
}
|
|
|
|
static const struct backlight_ops pwm_backlight_ops = {
|
|
.update_status = pwm_backlight_update_status,
|
|
.check_fb = pwm_backlight_check_fb,
|
|
};
|
|
|
|
#ifdef CONFIG_OF
|
|
static int pwm_backlight_parse_dt(struct device *dev,
|
|
struct platform_pwm_backlight_data *data)
|
|
{
|
|
struct device_node *node = dev->of_node;
|
|
struct property *prop;
|
|
int length;
|
|
u32 value;
|
|
int ret;
|
|
|
|
if (!node)
|
|
return -ENODEV;
|
|
|
|
memset(data, 0, sizeof(*data));
|
|
|
|
/* determine the number of brightness levels */
|
|
prop = of_find_property(node, "brightness-levels", &length);
|
|
if (!prop)
|
|
return -EINVAL;
|
|
|
|
data->max_brightness = length / sizeof(u32);
|
|
|
|
/* read brightness levels from DT property */
|
|
if (data->max_brightness > 0) {
|
|
size_t size = sizeof(*data->levels) * data->max_brightness;
|
|
|
|
data->levels = devm_kzalloc(dev, size, GFP_KERNEL);
|
|
if (!data->levels)
|
|
return -ENOMEM;
|
|
|
|
ret = of_property_read_u32_array(node, "brightness-levels",
|
|
data->levels,
|
|
data->max_brightness);
|
|
if (ret < 0)
|
|
return ret;
|
|
|
|
ret = of_property_read_u32(node, "default-brightness-level",
|
|
&value);
|
|
if (ret < 0)
|
|
return ret;
|
|
|
|
data->dft_brightness = value;
|
|
data->max_brightness--;
|
|
}
|
|
|
|
data->enable_gpio = -EINVAL;
|
|
return 0;
|
|
}
|
|
|
|
static struct of_device_id pwm_backlight_of_match[] = {
|
|
{ .compatible = "pwm-backlight" },
|
|
{ }
|
|
};
|
|
|
|
MODULE_DEVICE_TABLE(of, pwm_backlight_of_match);
|
|
#else
|
|
static int pwm_backlight_parse_dt(struct device *dev,
|
|
struct platform_pwm_backlight_data *data)
|
|
{
|
|
return -ENODEV;
|
|
}
|
|
#endif
|
|
|
|
static int pwm_backlight_probe(struct platform_device *pdev)
|
|
{
|
|
struct platform_pwm_backlight_data *data = dev_get_platdata(&pdev->dev);
|
|
struct platform_pwm_backlight_data defdata;
|
|
struct backlight_properties props;
|
|
struct backlight_device *bl;
|
|
struct pwm_bl_data *pb;
|
|
int ret;
|
|
|
|
if (!data) {
|
|
ret = pwm_backlight_parse_dt(&pdev->dev, &defdata);
|
|
if (ret < 0) {
|
|
dev_err(&pdev->dev, "failed to find platform data\n");
|
|
return ret;
|
|
}
|
|
|
|
data = &defdata;
|
|
}
|
|
|
|
if (data->init) {
|
|
ret = data->init(&pdev->dev);
|
|
if (ret < 0)
|
|
return ret;
|
|
}
|
|
|
|
pb = devm_kzalloc(&pdev->dev, sizeof(*pb), GFP_KERNEL);
|
|
if (!pb) {
|
|
ret = -ENOMEM;
|
|
goto err_alloc;
|
|
}
|
|
|
|
if (data->levels) {
|
|
unsigned int i;
|
|
|
|
for (i = 0; i <= data->max_brightness; i++)
|
|
if (data->levels[i] > pb->scale)
|
|
pb->scale = data->levels[i];
|
|
|
|
pb->levels = data->levels;
|
|
} else
|
|
pb->scale = data->max_brightness;
|
|
|
|
pb->notify = data->notify;
|
|
pb->notify_after = data->notify_after;
|
|
pb->check_fb = data->check_fb;
|
|
pb->exit = data->exit;
|
|
pb->dev = &pdev->dev;
|
|
pb->enabled = false;
|
|
|
|
pb->enable_gpio = devm_gpiod_get_optional(&pdev->dev, "enable");
|
|
if (IS_ERR(pb->enable_gpio)) {
|
|
ret = PTR_ERR(pb->enable_gpio);
|
|
goto err_alloc;
|
|
}
|
|
|
|
/*
|
|
* Compatibility fallback for drivers still using the integer GPIO
|
|
* platform data. Must go away soon.
|
|
*/
|
|
if (!pb->enable_gpio && gpio_is_valid(data->enable_gpio)) {
|
|
ret = devm_gpio_request_one(&pdev->dev, data->enable_gpio,
|
|
GPIOF_OUT_INIT_HIGH, "enable");
|
|
if (ret < 0) {
|
|
dev_err(&pdev->dev, "failed to request GPIO#%d: %d\n",
|
|
data->enable_gpio, ret);
|
|
goto err_alloc;
|
|
}
|
|
|
|
pb->enable_gpio = gpio_to_desc(data->enable_gpio);
|
|
}
|
|
|
|
if (pb->enable_gpio)
|
|
gpiod_direction_output(pb->enable_gpio, 1);
|
|
|
|
pb->power_supply = devm_regulator_get(&pdev->dev, "power");
|
|
if (IS_ERR(pb->power_supply)) {
|
|
ret = PTR_ERR(pb->power_supply);
|
|
goto err_alloc;
|
|
}
|
|
|
|
pb->pwm = devm_pwm_get(&pdev->dev, NULL);
|
|
if (IS_ERR(pb->pwm)) {
|
|
dev_err(&pdev->dev, "unable to request PWM, trying legacy API\n");
|
|
|
|
pb->pwm = pwm_request(data->pwm_id, "pwm-backlight");
|
|
if (IS_ERR(pb->pwm)) {
|
|
dev_err(&pdev->dev, "unable to request legacy PWM\n");
|
|
ret = PTR_ERR(pb->pwm);
|
|
goto err_alloc;
|
|
}
|
|
}
|
|
|
|
dev_dbg(&pdev->dev, "got pwm for backlight\n");
|
|
|
|
/*
|
|
* The DT case will set the pwm_period_ns field to 0 and store the
|
|
* period, parsed from the DT, in the PWM device. For the non-DT case,
|
|
* set the period from platform data if it has not already been set
|
|
* via the PWM lookup table.
|
|
*/
|
|
pb->period = pwm_get_period(pb->pwm);
|
|
if (!pb->period && (data->pwm_period_ns > 0)) {
|
|
pb->period = data->pwm_period_ns;
|
|
pwm_set_period(pb->pwm, data->pwm_period_ns);
|
|
}
|
|
|
|
pb->lth_brightness = data->lth_brightness * (pb->period / pb->scale);
|
|
|
|
memset(&props, 0, sizeof(struct backlight_properties));
|
|
props.type = BACKLIGHT_RAW;
|
|
props.max_brightness = data->max_brightness;
|
|
bl = backlight_device_register(dev_name(&pdev->dev), &pdev->dev, pb,
|
|
&pwm_backlight_ops, &props);
|
|
if (IS_ERR(bl)) {
|
|
dev_err(&pdev->dev, "failed to register backlight\n");
|
|
ret = PTR_ERR(bl);
|
|
goto err_alloc;
|
|
}
|
|
|
|
if (data->dft_brightness > data->max_brightness) {
|
|
dev_warn(&pdev->dev,
|
|
"invalid default brightness level: %u, using %u\n",
|
|
data->dft_brightness, data->max_brightness);
|
|
data->dft_brightness = data->max_brightness;
|
|
}
|
|
|
|
bl->props.brightness = data->dft_brightness;
|
|
backlight_update_status(bl);
|
|
|
|
platform_set_drvdata(pdev, bl);
|
|
return 0;
|
|
|
|
err_alloc:
|
|
if (data->exit)
|
|
data->exit(&pdev->dev);
|
|
return ret;
|
|
}
|
|
|
|
static int pwm_backlight_remove(struct platform_device *pdev)
|
|
{
|
|
struct backlight_device *bl = platform_get_drvdata(pdev);
|
|
struct pwm_bl_data *pb = bl_get_data(bl);
|
|
|
|
backlight_device_unregister(bl);
|
|
pwm_backlight_power_off(pb);
|
|
|
|
if (pb->exit)
|
|
pb->exit(&pdev->dev);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void pwm_backlight_shutdown(struct platform_device *pdev)
|
|
{
|
|
struct backlight_device *bl = platform_get_drvdata(pdev);
|
|
struct pwm_bl_data *pb = bl_get_data(bl);
|
|
|
|
pwm_backlight_power_off(pb);
|
|
}
|
|
|
|
#ifdef CONFIG_PM_SLEEP
|
|
static int pwm_backlight_suspend(struct device *dev)
|
|
{
|
|
struct backlight_device *bl = dev_get_drvdata(dev);
|
|
struct pwm_bl_data *pb = bl_get_data(bl);
|
|
|
|
if (pb->notify)
|
|
pb->notify(pb->dev, 0);
|
|
|
|
pwm_backlight_power_off(pb);
|
|
|
|
if (pb->notify_after)
|
|
pb->notify_after(pb->dev, 0);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int pwm_backlight_resume(struct device *dev)
|
|
{
|
|
struct backlight_device *bl = dev_get_drvdata(dev);
|
|
|
|
backlight_update_status(bl);
|
|
|
|
return 0;
|
|
}
|
|
#endif
|
|
|
|
static const struct dev_pm_ops pwm_backlight_pm_ops = {
|
|
#ifdef CONFIG_PM_SLEEP
|
|
.suspend = pwm_backlight_suspend,
|
|
.resume = pwm_backlight_resume,
|
|
.poweroff = pwm_backlight_suspend,
|
|
.restore = pwm_backlight_resume,
|
|
#endif
|
|
};
|
|
|
|
static struct platform_driver pwm_backlight_driver = {
|
|
.driver = {
|
|
.name = "pwm-backlight",
|
|
.owner = THIS_MODULE,
|
|
.pm = &pwm_backlight_pm_ops,
|
|
.of_match_table = of_match_ptr(pwm_backlight_of_match),
|
|
},
|
|
.probe = pwm_backlight_probe,
|
|
.remove = pwm_backlight_remove,
|
|
.shutdown = pwm_backlight_shutdown,
|
|
};
|
|
|
|
module_platform_driver(pwm_backlight_driver);
|
|
|
|
MODULE_DESCRIPTION("PWM based Backlight Driver");
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_ALIAS("platform:pwm-backlight");
|