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3b5765df37
Let's add support for being able to read the HPD pin even if it's hooked directly to the controller. This will let us take away the waiting in the AUX transfer functions of the eDP controller drivers. Signed-off-by: Douglas Anderson <dianders@chromium.org> Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org> Link: https://patchwork.freedesktop.org/patch/msgid/20220614145327.v4.3.I9ee239f6b95b944c8fa030f300ad222a7af9899d@changeid
392 lines
9.6 KiB
C
392 lines
9.6 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright 2021 Google Inc.
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*
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* Panel driver for the Samsung ATNA33XC20 panel. This panel can't be handled
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* by the DRM_PANEL_SIMPLE driver because its power sequencing is non-standard.
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*/
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#include <linux/backlight.h>
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#include <linux/delay.h>
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#include <linux/gpio/consumer.h>
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#include <linux/iopoll.h>
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#include <linux/module.h>
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#include <linux/pm_runtime.h>
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#include <linux/regulator/consumer.h>
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#include <drm/display/drm_dp_aux_bus.h>
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#include <drm/display/drm_dp_helper.h>
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#include <drm/drm_edid.h>
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#include <drm/drm_panel.h>
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/* T3 VCC to HPD high is max 200 ms */
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#define HPD_MAX_MS 200
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#define HPD_MAX_US (HPD_MAX_MS * 1000)
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struct atana33xc20_panel {
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struct drm_panel base;
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bool prepared;
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bool enabled;
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bool el3_was_on;
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bool no_hpd;
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struct gpio_desc *hpd_gpio;
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struct regulator *supply;
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struct gpio_desc *el_on3_gpio;
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struct drm_dp_aux *aux;
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struct edid *edid;
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ktime_t powered_off_time;
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ktime_t powered_on_time;
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ktime_t el_on3_off_time;
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};
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static inline struct atana33xc20_panel *to_atana33xc20(struct drm_panel *panel)
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{
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return container_of(panel, struct atana33xc20_panel, base);
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}
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static void atana33xc20_wait(ktime_t start_ktime, unsigned int min_ms)
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{
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ktime_t now_ktime, min_ktime;
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min_ktime = ktime_add(start_ktime, ms_to_ktime(min_ms));
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now_ktime = ktime_get();
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if (ktime_before(now_ktime, min_ktime))
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msleep(ktime_to_ms(ktime_sub(min_ktime, now_ktime)) + 1);
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}
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static int atana33xc20_suspend(struct device *dev)
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{
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struct atana33xc20_panel *p = dev_get_drvdata(dev);
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int ret;
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/*
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* Note 3 (Example of power off sequence in detail) in spec
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* specifies to wait 150 ms after deasserting EL3_ON before
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* powering off.
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*/
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if (p->el3_was_on)
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atana33xc20_wait(p->el_on3_off_time, 150);
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ret = regulator_disable(p->supply);
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if (ret)
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return ret;
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p->powered_off_time = ktime_get();
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p->el3_was_on = false;
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return 0;
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}
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static int atana33xc20_resume(struct device *dev)
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{
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struct atana33xc20_panel *p = dev_get_drvdata(dev);
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int hpd_asserted;
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int ret;
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/* T12 (Power off time) is min 500 ms */
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atana33xc20_wait(p->powered_off_time, 500);
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ret = regulator_enable(p->supply);
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if (ret)
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return ret;
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p->powered_on_time = ktime_get();
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if (p->no_hpd) {
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msleep(HPD_MAX_MS);
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return 0;
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}
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if (p->hpd_gpio) {
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ret = readx_poll_timeout(gpiod_get_value_cansleep, p->hpd_gpio,
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hpd_asserted, hpd_asserted,
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1000, HPD_MAX_US);
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if (hpd_asserted < 0)
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ret = hpd_asserted;
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if (ret)
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dev_warn(dev, "Error waiting for HPD GPIO: %d\n", ret);
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return ret;
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}
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if (p->aux->wait_hpd_asserted) {
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ret = p->aux->wait_hpd_asserted(p->aux, HPD_MAX_US);
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if (ret)
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dev_warn(dev, "Controller error waiting for HPD: %d\n", ret);
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return ret;
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}
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/*
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* Note that it's possible that no_hpd is false, hpd_gpio is
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* NULL, and wait_hpd_asserted is NULL. This is because
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* wait_hpd_asserted() is optional even if HPD is hooked up to
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* a dedicated pin on the eDP controller. In this case we just
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* assume that the controller driver will wait for HPD at the
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* right times.
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*/
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return 0;
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}
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static int atana33xc20_disable(struct drm_panel *panel)
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{
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struct atana33xc20_panel *p = to_atana33xc20(panel);
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/* Disabling when already disabled is a no-op */
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if (!p->enabled)
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return 0;
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gpiod_set_value_cansleep(p->el_on3_gpio, 0);
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p->el_on3_off_time = ktime_get();
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p->enabled = false;
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/*
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* Keep track of the fact that EL_ON3 was on but we haven't power
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* cycled yet. This lets us know that "el_on3_off_time" is recent (we
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* don't need to worry about ktime wraparounds) and also makes it
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* obvious if we try to enable again without a power cycle (see the
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* warning in atana33xc20_enable()).
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*/
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p->el3_was_on = true;
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/*
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* Sleeping 20 ms here (after setting the GPIO) avoids a glitch when
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* powering off.
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*/
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msleep(20);
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return 0;
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}
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static int atana33xc20_enable(struct drm_panel *panel)
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{
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struct atana33xc20_panel *p = to_atana33xc20(panel);
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/* Enabling when already enabled is a no-op */
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if (p->enabled)
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return 0;
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/*
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* Once EL_ON3 drops we absolutely need a power cycle before the next
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* enable or the backlight will never come on again. The code ensures
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* this because disable() is _always_ followed by unprepare() and
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* unprepare() forces a suspend with pm_runtime_put_sync_suspend(),
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* but let's track just to make sure since the requirement is so
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* non-obvious.
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*/
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if (WARN_ON(p->el3_was_on))
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return -EIO;
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/*
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* Note 2 (Example of power on sequence in detail) in spec specifies
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* to wait 400 ms after powering on before asserting EL3_on.
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*/
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atana33xc20_wait(p->powered_on_time, 400);
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gpiod_set_value_cansleep(p->el_on3_gpio, 1);
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p->enabled = true;
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return 0;
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}
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static int atana33xc20_unprepare(struct drm_panel *panel)
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{
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struct atana33xc20_panel *p = to_atana33xc20(panel);
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int ret;
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/* Unpreparing when already unprepared is a no-op */
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if (!p->prepared)
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return 0;
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/*
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* Purposely do a put_sync, don't use autosuspend. The panel's tcon
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* seems to sometimes crash when you stop giving it data and this is
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* the best way to ensure it will come back.
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*
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* NOTE: we still want autosuspend for cases where we only turn on
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* to get the EDID or otherwise send DP AUX commands to the panel.
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*/
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ret = pm_runtime_put_sync_suspend(panel->dev);
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if (ret < 0)
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return ret;
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p->prepared = false;
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return 0;
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}
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static int atana33xc20_prepare(struct drm_panel *panel)
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{
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struct atana33xc20_panel *p = to_atana33xc20(panel);
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int ret;
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/* Preparing when already prepared is a no-op */
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if (p->prepared)
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return 0;
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ret = pm_runtime_get_sync(panel->dev);
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if (ret < 0) {
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pm_runtime_put_autosuspend(panel->dev);
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return ret;
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}
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p->prepared = true;
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return 0;
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}
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static int atana33xc20_get_modes(struct drm_panel *panel,
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struct drm_connector *connector)
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{
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struct atana33xc20_panel *p = to_atana33xc20(panel);
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struct dp_aux_ep_device *aux_ep = to_dp_aux_ep_dev(panel->dev);
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int num = 0;
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pm_runtime_get_sync(panel->dev);
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if (!p->edid)
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p->edid = drm_get_edid(connector, &aux_ep->aux->ddc);
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num = drm_add_edid_modes(connector, p->edid);
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pm_runtime_mark_last_busy(panel->dev);
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pm_runtime_put_autosuspend(panel->dev);
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return num;
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}
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static const struct drm_panel_funcs atana33xc20_funcs = {
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.disable = atana33xc20_disable,
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.enable = atana33xc20_enable,
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.unprepare = atana33xc20_unprepare,
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.prepare = atana33xc20_prepare,
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.get_modes = atana33xc20_get_modes,
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};
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static void atana33xc20_runtime_disable(void *data)
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{
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pm_runtime_disable(data);
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}
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static void atana33xc20_dont_use_autosuspend(void *data)
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{
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pm_runtime_dont_use_autosuspend(data);
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}
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static int atana33xc20_probe(struct dp_aux_ep_device *aux_ep)
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{
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struct atana33xc20_panel *panel;
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struct device *dev = &aux_ep->dev;
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int ret;
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panel = devm_kzalloc(dev, sizeof(*panel), GFP_KERNEL);
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if (!panel)
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return -ENOMEM;
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dev_set_drvdata(dev, panel);
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panel->aux = aux_ep->aux;
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panel->supply = devm_regulator_get(dev, "power");
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if (IS_ERR(panel->supply))
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return dev_err_probe(dev, PTR_ERR(panel->supply),
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"Failed to get power supply\n");
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panel->el_on3_gpio = devm_gpiod_get(dev, "enable", GPIOD_OUT_LOW);
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if (IS_ERR(panel->el_on3_gpio))
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return dev_err_probe(dev, PTR_ERR(panel->el_on3_gpio),
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"Failed to get enable GPIO\n");
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panel->no_hpd = of_property_read_bool(dev->of_node, "no-hpd");
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if (!panel->no_hpd) {
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panel->hpd_gpio = devm_gpiod_get_optional(dev, "hpd", GPIOD_IN);
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if (IS_ERR(panel->hpd_gpio))
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return dev_err_probe(dev, PTR_ERR(panel->hpd_gpio),
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"Failed to get HPD GPIO\n");
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}
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pm_runtime_enable(dev);
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ret = devm_add_action_or_reset(dev, atana33xc20_runtime_disable, dev);
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if (ret)
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return ret;
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pm_runtime_set_autosuspend_delay(dev, 1000);
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pm_runtime_use_autosuspend(dev);
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ret = devm_add_action_or_reset(dev, atana33xc20_dont_use_autosuspend, dev);
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if (ret)
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return ret;
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drm_panel_init(&panel->base, dev, &atana33xc20_funcs, DRM_MODE_CONNECTOR_eDP);
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pm_runtime_get_sync(dev);
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ret = drm_panel_dp_aux_backlight(&panel->base, aux_ep->aux);
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pm_runtime_mark_last_busy(dev);
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pm_runtime_put_autosuspend(dev);
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if (ret)
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return dev_err_probe(dev, ret,
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"failed to register dp aux backlight\n");
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drm_panel_add(&panel->base);
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return 0;
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}
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static void atana33xc20_remove(struct dp_aux_ep_device *aux_ep)
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{
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struct device *dev = &aux_ep->dev;
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struct atana33xc20_panel *panel = dev_get_drvdata(dev);
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drm_panel_remove(&panel->base);
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drm_panel_disable(&panel->base);
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drm_panel_unprepare(&panel->base);
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kfree(panel->edid);
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}
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static void atana33xc20_shutdown(struct dp_aux_ep_device *aux_ep)
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{
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struct device *dev = &aux_ep->dev;
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struct atana33xc20_panel *panel = dev_get_drvdata(dev);
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drm_panel_disable(&panel->base);
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drm_panel_unprepare(&panel->base);
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}
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static const struct of_device_id atana33xc20_dt_match[] = {
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{ .compatible = "samsung,atna33xc20", },
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{ /* sentinal */ }
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};
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MODULE_DEVICE_TABLE(of, atana33xc20_dt_match);
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static const struct dev_pm_ops atana33xc20_pm_ops = {
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SET_RUNTIME_PM_OPS(atana33xc20_suspend, atana33xc20_resume, NULL)
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SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
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pm_runtime_force_resume)
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};
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static struct dp_aux_ep_driver atana33xc20_driver = {
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.driver = {
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.name = "samsung_atana33xc20",
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.of_match_table = atana33xc20_dt_match,
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.pm = &atana33xc20_pm_ops,
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},
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.probe = atana33xc20_probe,
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.remove = atana33xc20_remove,
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.shutdown = atana33xc20_shutdown,
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};
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static int __init atana33xc20_init(void)
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{
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return dp_aux_dp_driver_register(&atana33xc20_driver);
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}
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module_init(atana33xc20_init);
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static void __exit atana33xc20_exit(void)
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{
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dp_aux_dp_driver_unregister(&atana33xc20_driver);
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}
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module_exit(atana33xc20_exit);
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MODULE_DESCRIPTION("Samsung ATANA33XC20 Panel Driver");
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MODULE_LICENSE("GPL v2");
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