The Samsung ATNA33XC20 panel is an AMOLED eDP panel that has backlight control over the DP AUX channel.
This panel is _almost_ able to be controlled in a "simple" way (and it originally was implemented in panel-simple.c), but it's really impossible to get the backlight semantics right there without adding wacky special-case code to panel-simple. Let's give up and clone the parts of panel-simple that we need and implement the power sequence that this panel needs.
NOTE: we'll still leave the devicetree bindings alone. Even though the power-sequencing is non-standard the bindings are still "simple".
Signed-off-by: Douglas Anderson dianders@chromium.org Reviewed-by: Sean Paul seanpaul@chromium.org ---
(no changes since v1)
drivers/gpu/drm/panel/Kconfig | 12 + drivers/gpu/drm/panel/Makefile | 1 + .../gpu/drm/panel/panel-samsung-atna33xc20.c | 366 ++++++++++++++++++ 3 files changed, 379 insertions(+) create mode 100644 drivers/gpu/drm/panel/panel-samsung-atna33xc20.c
diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig index 6b3eb041182c..58430d358489 100644 --- a/drivers/gpu/drm/panel/Kconfig +++ b/drivers/gpu/drm/panel/Kconfig @@ -353,6 +353,18 @@ config DRM_PANEL_RONBO_RB070D30 Say Y here if you want to enable support for Ronbo Electronics RB070D30 1024x600 DSI panel.
+config DRM_PANEL_SAMSUNG_ATNA33XC20 + tristate "Samsung ATNA33XC20 eDP panel" + depends on OF + depends on BACKLIGHT_CLASS_DEVICE + depends on PM + select VIDEOMODE_HELPERS + select DRM_DP_AUX_BUS + help + DRM 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. + config DRM_PANEL_SAMSUNG_DB7430 tristate "Samsung DB7430-based DPI panels" depends on OF && SPI && GPIOLIB diff --git a/drivers/gpu/drm/panel/Makefile b/drivers/gpu/drm/panel/Makefile index 08debae9b314..1b6fe2008861 100644 --- a/drivers/gpu/drm/panel/Makefile +++ b/drivers/gpu/drm/panel/Makefile @@ -34,6 +34,7 @@ obj-$(CONFIG_DRM_PANEL_RASPBERRYPI_TOUCHSCREEN) += panel-raspberrypi-touchscreen obj-$(CONFIG_DRM_PANEL_RAYDIUM_RM67191) += panel-raydium-rm67191.o obj-$(CONFIG_DRM_PANEL_RAYDIUM_RM68200) += panel-raydium-rm68200.o obj-$(CONFIG_DRM_PANEL_RONBO_RB070D30) += panel-ronbo-rb070d30.o +obj-$(CONFIG_DRM_PANEL_SAMSUNG_ATNA33XC20) += panel-samsung-atna33xc20.o obj-$(CONFIG_DRM_PANEL_SAMSUNG_DB7430) += panel-samsung-db7430.o obj-$(CONFIG_DRM_PANEL_SAMSUNG_LD9040) += panel-samsung-ld9040.o obj-$(CONFIG_DRM_PANEL_SAMSUNG_S6D16D0) += panel-samsung-s6d16d0.o diff --git a/drivers/gpu/drm/panel/panel-samsung-atna33xc20.c b/drivers/gpu/drm/panel/panel-samsung-atna33xc20.c new file mode 100644 index 000000000000..221db6512859 --- /dev/null +++ b/drivers/gpu/drm/panel/panel-samsung-atna33xc20.c @@ -0,0 +1,366 @@ +// 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/drm_dp_aux_bus.h> +#include <drm/drm_dp_helper.h> +#include <drm/drm_edid.h> +#include <drm/drm_panel.h> + +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 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(); + + 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); + + ret = regulator_disable(p->supply); + if (ret) + return ret; + p->powered_off_time = ktime_get(); + p->el3_was_on = false; + + return 0; +} + +static int atana33xc20_resume(struct device *dev) +{ + struct atana33xc20_panel *p = dev_get_drvdata(dev); + bool hpd_asserted = false; + 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; + p->powered_on_time = ktime_get(); + + /* + * Handle HPD. Note: if HPD is hooked up to a dedicated pin on the + * eDP controller then "no_hpd" will be false _and_ "hpd_gpio" will be + * NULL. It's up to the controller driver to wait for HPD after + * preparing the panel in that case. + */ + if (p->no_hpd) { + /* T3 VCC to HPD high is max 200 ms */ + msleep(200); + } else if (p->hpd_gpio) { + ret = readx_poll_timeout(gpiod_get_value_cansleep, p->hpd_gpio, + hpd_asserted, hpd_asserted, + 1000, 200000); + if (!hpd_asserted) + dev_warn(dev, "Timeout waiting for HPD\n"); + } + + 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(); + 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->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, 1000); + 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");