drivers/gpu/drm/panel/panel-samsung-atna33xc20.c - linux - Git at Google

 // 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");
	// 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");