// SPDX-License-Identifier: GPL-2.0
/*
* Copyright 2021 Google Inc.
*
* Panel driver for the Samsung ATNA33XC20 panel. This panel can't be handled
* by the DRM_PANEL_SIMPLE driver because its power sequencing is non-standard.
*/
#include <linux/backlight.h>
#include <linux/delay.h>
#include <linux/gpio/consumer.h>
#include <linux/iopoll.h>
#include <linux/module.h>
#include <linux/pm_runtime.h>
#include <linux/regulator/consumer.h>
#include <drm/display/drm_dp_aux_bus.h>
#include <drm/display/drm_dp_helper.h>
#include <drm/drm_edid.h>
#include <drm/drm_panel.h>
/* T3 VCC to HPD high is max 200 ms */
#define HPD_MAX_MS 200
#define HPD_MAX_US (HPD_MAX_MS * 1000)
struct atana33xc20_panel {
struct drm_panel base;
bool el3_was_on;
bool no_hpd;
struct gpio_desc *hpd_gpio;
struct regulator *supply;
struct gpio_desc *el_on3_gpio;
struct drm_dp_aux *aux;
const struct drm_edid *drm_edid;
ktime_t powered_off_time;
ktime_t powered_on_time;
ktime_t el_on3_off_time;
};
static inline struct atana33xc20_panel *to_atana33xc20(struct drm_panel *panel)
{
return container_of(panel, struct atana33xc20_panel, base);
}
static void atana33xc20_wait(ktime_t start_ktime, unsigned int min_ms)
{
ktime_t now_ktime, min_ktime;
min_ktime = ktime_add(start_ktime, ms_to_ktime(min_ms));
now_ktime = ktime_get_boottime();
if (ktime_before(now_ktime, min_ktime))
msleep(ktime_to_ms(ktime_sub(min_ktime, now_ktime)) + 1);
}
static int atana33xc20_suspend(struct device *dev)
{
struct atana33xc20_panel *p = dev_get_drvdata(dev);
int ret;
/*
* Note 3 (Example of power off sequence in detail) in spec
* specifies to wait 150 ms after deasserting EL3_ON before
* powering off.
*/
if (p->el3_was_on)
atana33xc20_wait(p->el_on3_off_time, 150);
drm_dp_dpcd_set_powered(p->aux, false);
ret = regulator_disable(p->supply);
if (ret)
return ret;
p->powered_off_time = ktime_get_boottime();
p->el3_was_on = false;
return 0;
}
static int atana33xc20_resume(struct device *dev)
{
struct atana33xc20_panel *p = dev_get_drvdata(dev);
int hpd_asserted;
int ret;
/* T12 (Power off time) is min 500 ms */
atana33xc20_wait(p->powered_off_time, 500);
ret = regulator_enable(p->supply);
if (ret)
return ret;
drm_dp_dpcd_set_powered(p->aux, true);
p->powered_on_time = ktime_get_boottime();
if (p->no_hpd) {
msleep(HPD_MAX_MS);
return 0;
}
if (p->hpd_gpio) {
ret = readx_poll_timeout(gpiod_get_value_cansleep, p->hpd_gpio,
hpd_asserted, hpd_asserted,
1000, HPD_MAX_US);
if (hpd_asserted < 0)
ret = hpd_asserted;
if (ret) {
dev_warn(dev, "Error waiting for HPD GPIO: %d\n", ret);
goto error;
}
} else if (p->aux->wait_hpd_asserted) {
ret = p->aux->wait_hpd_asserted(p->aux, HPD_MAX_US);
if (ret) {
dev_warn(dev, "Controller error waiting for HPD: %d\n", ret);
goto error;
}
}
/*
* Note that it's possible that no_hpd is false, hpd_gpio is
* NULL, and wait_hpd_asserted is NULL. This is because
* wait_hpd_asserted() is optional even if HPD is hooked up to
* a dedicated pin on the eDP controller. In this case we just
* assume that the controller driver will wait for HPD at the
* right times.
*/
return 0;
error:
drm_dp_dpcd_set_powered(p->aux, false);
regulator_disable(p->supply);
return ret;
}
static int atana33xc20_disable(struct drm_panel *panel)
{
struct atana33xc20_panel *p = to_atana33xc20(panel);
gpiod_set_value_cansleep(p->el_on3_gpio, 0);
p->el_on3_off_time = ktime_get_boottime();
/*
* Keep track of the fact that EL_ON3 was on but we haven't power
* cycled yet. This lets us know that "el_on3_off_time" is recent (we
* don't need to worry about ktime wraparounds) and also makes it
* obvious if we try to enable again without a power cycle (see the
* warning in atana33xc20_enable()).
*/
p->el3_was_on = true;
/*
* Sleeping 20 ms here (after setting the GPIO) avoids a glitch when
* powering off.
*/
msleep(20);
return 0;
}
static int atana33xc20_enable(struct drm_panel *panel)
{
struct atana33xc20_panel *p = to_atana33xc20(panel);
/*
* Once EL_ON3 drops we absolutely need a power cycle before the next
* enable or the backlight will never come on again. The code ensures
* this because disable() is _always_ followed by unprepare() and
* unprepare() forces a suspend with pm_runtime_put_sync_suspend(),
* but let's track just to make sure since the requirement is so
* non-obvious.
*/
if (WARN_ON(p->el3_was_on))
return -EIO;
/*
* Note 2 (Example of power on sequence in detail) in spec specifies
* to wait 400 ms after powering on before asserting EL3_on.
*/
atana33xc20_wait(p->powered_on_time, 400);
gpiod_set_value_cansleep(p->el_on3_gpio, 1);
return 0;
}
static int atana33xc20_unprepare(struct drm_panel *panel)
{
int ret;
/*
* Purposely do a put_sync, don't use autosuspend. The panel's tcon
* seems to sometimes crash when you stop giving it data and this is
* the best way to ensure it will come back.
*
* NOTE: we still want autosuspend for cases where we only turn on
* to get the EDID or otherwise send DP AUX commands to the panel.
*/
ret = pm_runtime_put_sync_suspend(panel->dev);
if (ret < 0)
return ret;
return 0;
}
static int atana33xc20_prepare(struct drm_panel *panel)
{
int ret;
ret = pm_runtime_get_sync(panel->dev);
if (ret < 0) {
pm_runtime_put_autosuspend(panel->dev);
return ret;
}
return 0;
}
static int atana33xc20_get_modes(struct drm_panel *panel,
struct drm_connector *connector)
{
struct atana33xc20_panel *p = to_atana33xc20(panel);
struct dp_aux_ep_device *aux_ep = to_dp_aux_ep_dev(panel->dev);
int num = 0;
pm_runtime_get_sync(panel->dev);
if (!p->drm_edid)
p->drm_edid = drm_edid_read_ddc(connector, &aux_ep->aux->ddc);
drm_edid_connector_update(connector, p->drm_edid);
num = drm_edid_connector_add_modes(connector);
pm_runtime_mark_last_busy(panel->dev);
pm_runtime_put_autosuspend(panel->dev);
return num;
}
static const struct drm_panel_funcs atana33xc20_funcs = {
.disable = atana33xc20_disable,
.enable = atana33xc20_enable,
.unprepare = atana33xc20_unprepare,
.prepare = atana33xc20_prepare,
.get_modes = atana33xc20_get_modes,
};
static void atana33xc20_runtime_disable(void *data)
{
pm_runtime_disable(data);
}
static void atana33xc20_dont_use_autosuspend(void *data)
{
pm_runtime_dont_use_autosuspend(data);
}
static int atana33xc20_probe(struct dp_aux_ep_device *aux_ep)
{
struct atana33xc20_panel *panel;
struct device *dev = &aux_ep->dev;
int ret;
panel = devm_kzalloc(dev, sizeof(*panel), GFP_KERNEL);
if (!panel)
return -ENOMEM;
dev_set_drvdata(dev, panel);
panel->aux = aux_ep->aux;
panel->supply = devm_regulator_get(dev, "power");
if (IS_ERR(panel->supply))
return dev_err_probe(dev, PTR_ERR(panel->supply),
"Failed to get power supply\n");
panel->el_on3_gpio = devm_gpiod_get(dev, "enable", GPIOD_OUT_LOW);
if (IS_ERR(panel->el_on3_gpio))
return dev_err_probe(dev, PTR_ERR(panel->el_on3_gpio),
"Failed to get enable GPIO\n");
panel->no_hpd = of_property_read_bool(dev->of_node, "no-hpd");
if (!panel->no_hpd) {
panel->hpd_gpio = devm_gpiod_get_optional(dev, "hpd", GPIOD_IN);
if (IS_ERR(panel->hpd_gpio))
return dev_err_probe(dev, PTR_ERR(panel->hpd_gpio),
"Failed to get HPD GPIO\n");
}
pm_runtime_enable(dev);
ret = devm_add_action_or_reset(dev, atana33xc20_runtime_disable, dev);
if (ret)
return ret;
pm_runtime_set_autosuspend_delay(dev, 2000);
pm_runtime_use_autosuspend(dev);
ret = devm_add_action_or_reset(dev, atana33xc20_dont_use_autosuspend, dev);
if (ret)
return ret;
drm_panel_init(&panel->base, dev, &atana33xc20_funcs, DRM_MODE_CONNECTOR_eDP);
pm_runtime_get_sync(dev);
ret = drm_panel_dp_aux_backlight(&panel->base, aux_ep->aux);
pm_runtime_mark_last_busy(dev);
pm_runtime_put_autosuspend(dev);
/*
* Warn if we get an error, but don't consider it fatal. Having
* a panel where we can't control the backlight is better than
* no panel.
*/
if (ret)
dev_warn(dev, "failed to register dp aux backlight: %d\n", ret);
drm_panel_add(&panel->base);
return 0;
}
static void atana33xc20_remove(struct dp_aux_ep_device *aux_ep)
{
struct device *dev = &aux_ep->dev;
struct atana33xc20_panel *panel = dev_get_drvdata(dev);
drm_panel_remove(&panel->base);
drm_edid_free(panel->drm_edid);
}
static const struct of_device_id atana33xc20_dt_match[] = {
{ .compatible = "samsung,atna33xc20", },
{ /* sentinal */ }
};
MODULE_DEVICE_TABLE(of, atana33xc20_dt_match);
static const struct dev_pm_ops atana33xc20_pm_ops = {
SET_RUNTIME_PM_OPS(atana33xc20_suspend, atana33xc20_resume, NULL)
SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
pm_runtime_force_resume)
};
static struct dp_aux_ep_driver atana33xc20_driver = {
.driver = {
.name = "samsung_atana33xc20",
.of_match_table = atana33xc20_dt_match,
.pm = &atana33xc20_pm_ops,
},
.probe = atana33xc20_probe,
.remove = atana33xc20_remove,
};
static int __init atana33xc20_init(void)
{
return dp_aux_dp_driver_register(&atana33xc20_driver);
}
module_init(atana33xc20_init);
static void __exit atana33xc20_exit(void)
{
dp_aux_dp_driver_unregister(&atana33xc20_driver);
}
module_exit(atana33xc20_exit);
MODULE_DESCRIPTION("Samsung ATANA33XC20 Panel Driver");
MODULE_LICENSE("GPL v2");
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