linux/drivers/gpu/drm/msm/hdmi/hdmi_hpd.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2013 Red Hat
 * Author: Rob Clark <robdclark@gmail.com>
 */

#include <linux/delay.h>
#include <linux/gpio/consumer.h>
#include <linux/pinctrl/consumer.h>

#include "msm_kms.h"
#include "hdmi.h"

static void msm_hdmi_phy_reset(struct hdmi *hdmi)
{
	unsigned int val;

	val = hdmi_read(hdmi, REG_HDMI_PHY_CTRL);

	if (val & HDMI_PHY_CTRL_SW_RESET_LOW) {
		/* pull low */
		hdmi_write(hdmi, REG_HDMI_PHY_CTRL,
				val & ~HDMI_PHY_CTRL_SW_RESET);
	} else {
		/* pull high */
		hdmi_write(hdmi, REG_HDMI_PHY_CTRL,
				val | HDMI_PHY_CTRL_SW_RESET);
	}

	if (val & HDMI_PHY_CTRL_SW_RESET_PLL_LOW) {
		/* pull low */
		hdmi_write(hdmi, REG_HDMI_PHY_CTRL,
				val & ~HDMI_PHY_CTRL_SW_RESET_PLL);
	} else {
		/* pull high */
		hdmi_write(hdmi, REG_HDMI_PHY_CTRL,
				val | HDMI_PHY_CTRL_SW_RESET_PLL);
	}

	msleep(100);

	if (val & HDMI_PHY_CTRL_SW_RESET_LOW) {
		/* pull high */
		hdmi_write(hdmi, REG_HDMI_PHY_CTRL,
				val | HDMI_PHY_CTRL_SW_RESET);
	} else {
		/* pull low */
		hdmi_write(hdmi, REG_HDMI_PHY_CTRL,
				val & ~HDMI_PHY_CTRL_SW_RESET);
	}

	if (val & HDMI_PHY_CTRL_SW_RESET_PLL_LOW) {
		/* pull high */
		hdmi_write(hdmi, REG_HDMI_PHY_CTRL,
				val | HDMI_PHY_CTRL_SW_RESET_PLL);
	} else {
		/* pull low */
		hdmi_write(hdmi, REG_HDMI_PHY_CTRL,
				val & ~HDMI_PHY_CTRL_SW_RESET_PLL);
	}
}

void msm_hdmi_hpd_enable(struct drm_bridge *bridge)
{
	struct hdmi_bridge *hdmi_bridge = to_hdmi_bridge(bridge);
	struct hdmi *hdmi = hdmi_bridge->hdmi;
	struct device *dev = &hdmi->pdev->dev;
	uint32_t hpd_ctrl;
	int ret;
	unsigned long flags;

	if (hdmi->hpd_gpiod)
		gpiod_set_value_cansleep(hdmi->hpd_gpiod, 1);

	ret = pm_runtime_resume_and_get(dev);
	if (WARN_ON(ret))
		return;

	mutex_lock(&hdmi->state_mutex);
	msm_hdmi_set_mode(hdmi, false);
	msm_hdmi_phy_reset(hdmi);
	msm_hdmi_set_mode(hdmi, true);

	hdmi->hpd_enabled = true;
	mutex_unlock(&hdmi->state_mutex);

	hdmi_write(hdmi, REG_HDMI_USEC_REFTIMER, 0x0001001b);

	/* enable HPD events: */
	hdmi_write(hdmi, REG_HDMI_HPD_INT_CTRL,
			HDMI_HPD_INT_CTRL_INT_CONNECT |
			HDMI_HPD_INT_CTRL_INT_EN);

	/* set timeout to 4.1ms (max) for hardware debounce */
	spin_lock_irqsave(&hdmi->reg_lock, flags);
	hpd_ctrl = hdmi_read(hdmi, REG_HDMI_HPD_CTRL);
	hpd_ctrl |= HDMI_HPD_CTRL_TIMEOUT(0x1fff);

	/* Toggle HPD circuit to trigger HPD sense */
	hdmi_write(hdmi, REG_HDMI_HPD_CTRL,
			~HDMI_HPD_CTRL_ENABLE & hpd_ctrl);
	hdmi_write(hdmi, REG_HDMI_HPD_CTRL,
			HDMI_HPD_CTRL_ENABLE | hpd_ctrl);
	spin_unlock_irqrestore(&hdmi->reg_lock, flags);
}

void msm_hdmi_hpd_disable(struct drm_bridge *bridge)
{
	struct hdmi_bridge *hdmi_bridge = to_hdmi_bridge(bridge);
	struct hdmi *hdmi = hdmi_bridge->hdmi;
	struct device *dev = &hdmi->pdev->dev;

	/* Disable HPD interrupt */
	hdmi_write(hdmi, REG_HDMI_HPD_INT_CTRL, 0);

	mutex_lock(&hdmi->state_mutex);
	hdmi->hpd_enabled = false;
	msm_hdmi_set_mode(hdmi, hdmi->power_on);
	mutex_unlock(&hdmi->state_mutex);

	pm_runtime_put(dev);
}

void msm_hdmi_hpd_irq(struct drm_bridge *bridge)
{
	struct hdmi_bridge *hdmi_bridge = to_hdmi_bridge(bridge);
	struct hdmi *hdmi = hdmi_bridge->hdmi;
	uint32_t hpd_int_status, hpd_int_ctrl;

	/* Process HPD: */
	hpd_int_status = hdmi_read(hdmi, REG_HDMI_HPD_INT_STATUS);
	hpd_int_ctrl   = hdmi_read(hdmi, REG_HDMI_HPD_INT_CTRL);

	if ((hpd_int_ctrl & HDMI_HPD_INT_CTRL_INT_EN) &&
			(hpd_int_status & HDMI_HPD_INT_STATUS_INT)) {
		bool detected = !!(hpd_int_status & HDMI_HPD_INT_STATUS_CABLE_DETECTED);

		/* ack & disable (temporarily) HPD events: */
		hdmi_write(hdmi, REG_HDMI_HPD_INT_CTRL,
			HDMI_HPD_INT_CTRL_INT_ACK);

		DBG("status=%04x, ctrl=%04x", hpd_int_status, hpd_int_ctrl);

		/* detect disconnect if we are connected or visa versa: */
		hpd_int_ctrl = HDMI_HPD_INT_CTRL_INT_EN;
		if (!detected)
			hpd_int_ctrl |= HDMI_HPD_INT_CTRL_INT_CONNECT;
		hdmi_write(hdmi, REG_HDMI_HPD_INT_CTRL, hpd_int_ctrl);

		queue_work(hdmi->workq, &hdmi_bridge->hpd_work);
	}
}

static enum drm_connector_status detect_reg(struct hdmi *hdmi)
{
	u32 hpd_int_status = 0;
	int ret;

	ret = pm_runtime_resume_and_get(&hdmi->pdev->dev);
	if (ret)
		goto out;

	hpd_int_status = hdmi_read(hdmi, REG_HDMI_HPD_INT_STATUS);

out:
	pm_runtime_put(&hdmi->pdev->dev);

	return (hpd_int_status & HDMI_HPD_INT_STATUS_CABLE_DETECTED) ?
			connector_status_connected : connector_status_disconnected;
}

#define HPD_GPIO_INDEX	2
static enum drm_connector_status detect_gpio(struct hdmi *hdmi)
{
	return gpiod_get_value(hdmi->hpd_gpiod) ?
			connector_status_connected :
			connector_status_disconnected;
}

enum drm_connector_status
msm_hdmi_bridge_detect(struct drm_bridge *bridge, struct drm_connector *connector)
{
	struct hdmi_bridge *hdmi_bridge = to_hdmi_bridge(bridge);
	struct hdmi *hdmi = hdmi_bridge->hdmi;
	enum drm_connector_status stat_gpio, stat_reg;
	int retry = 20;

	/*
	 * some platforms may not have hpd gpio. Rely only on the status
	 * provided by REG_HDMI_HPD_INT_STATUS in this case.
	 */
	if (!hdmi->hpd_gpiod)
		return detect_reg(hdmi);

	do {
		stat_gpio = detect_gpio(hdmi);
		stat_reg  = detect_reg(hdmi);

		if (stat_gpio == stat_reg)
			break;

		mdelay(10);
	} while (--retry);

	/* the status we get from reading gpio seems to be more reliable,
	 * so trust that one the most if we didn't manage to get hdmi and
	 * gpio status to agree:
	 */
	if (stat_gpio != stat_reg) {
		DBG("HDMI_HPD_INT_STATUS tells us: %d", stat_reg);
		DBG("hpd gpio tells us: %d", stat_gpio);
	}

	return stat_gpio;
}