| // 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 prepared; |
| bool enabled; |
| 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; |
| |
| struct edid *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); |
| |
| return ret; |
| } |
| |
| 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); |
| |
| return ret; |
| } |
| |
| /* |
| * 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; |
| } |
| |
| static int atana33xc20_disable(struct drm_panel *panel) |
| { |
| struct atana33xc20_panel *p = to_atana33xc20(panel); |
| |
| /* Disabling when already disabled is a no-op */ |
| if (!p->enabled) |
| return 0; |
| |
| gpiod_set_value_cansleep(p->el_on3_gpio, 0); |
| p->el_on3_off_time = ktime_get_boottime(); |
| p->enabled = false; |
| |
| /* |
| * 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); |
| |
| /* Enabling when already enabled is a no-op */ |
| if (p->enabled) |
| return 0; |
| |
| /* |
| * 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); |
| p->enabled = true; |
| |
| return 0; |
| } |
| |
| static int atana33xc20_unprepare(struct drm_panel *panel) |
| { |
| struct atana33xc20_panel *p = to_atana33xc20(panel); |
| int ret; |
| |
| /* Unpreparing when already unprepared is a no-op */ |
| if (!p->prepared) |
| return 0; |
| |
| /* |
| * 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; |
| p->prepared = false; |
| |
| return 0; |
| } |
| |
| static int atana33xc20_prepare(struct drm_panel *panel) |
| { |
| struct atana33xc20_panel *p = to_atana33xc20(panel); |
| int ret; |
| |
| /* Preparing when already prepared is a no-op */ |
| if (p->prepared) |
| return 0; |
| |
| ret = pm_runtime_get_sync(panel->dev); |
| if (ret < 0) { |
| pm_runtime_put_autosuspend(panel->dev); |
| return ret; |
| } |
| p->prepared = true; |
| |
| 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->edid) |
| p->edid = drm_get_edid(connector, &aux_ep->aux->ddc); |
| num = drm_add_edid_modes(connector, p->edid); |
| |
| 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); |
| if (ret) |
| return dev_err_probe(dev, ret, |
| "failed to register dp aux backlight\n"); |
| |
| 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_panel_disable(&panel->base); |
| drm_panel_unprepare(&panel->base); |
| |
| kfree(panel->edid); |
| } |
| |
| static void atana33xc20_shutdown(struct dp_aux_ep_device *aux_ep) |
| { |
| struct device *dev = &aux_ep->dev; |
| struct atana33xc20_panel *panel = dev_get_drvdata(dev); |
| |
| drm_panel_disable(&panel->base); |
| drm_panel_unprepare(&panel->base); |
| } |
| |
| 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, |
| .shutdown = atana33xc20_shutdown, |
| }; |
| |
| 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"); |