drm/tegra: Add eDP support

Add support for eDP functionality found on Tegra124 and later SoCs. Only
fast link training is currently supported.

Signed-off-by: Thierry Reding <treding@nvidia.com>

1 files changed, 544 insertions, 0 deletions

diff --git a/drivers/gpu/drm/tegra/dpaux.c b/drivers/gpu/drm/tegra/dpaux.c
new file mode 100644
index 000000000000..d536ed381fbd
--- /dev/null
+++ b/drivers/gpu/drm/tegra/dpaux.c
@@ -0,0 +1,544 @@
+/*
+ * Copyright (C) 2013 NVIDIA Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/gpio.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/of_gpio.h>
+#include <linux/platform_device.h>
+#include <linux/reset.h>
+#include <linux/regulator/consumer.h>
+
+#include <drm/drm_dp_helper.h>
+#include <drm/drm_panel.h>
+
+#include "dpaux.h"
+#include "drm.h"
+
+static DEFINE_MUTEX(dpaux_lock);
+static LIST_HEAD(dpaux_list);
+
+struct tegra_dpaux {
+	struct drm_dp_aux aux;
+	struct device *dev;
+
+	void __iomem *regs;
+	int irq;
+
+	struct tegra_output *output;
+
+	struct reset_control *rst;
+	struct clk *clk_parent;
+	struct clk *clk;
+
+	struct regulator *vdd;
+
+	struct completion complete;
+	struct list_head list;
+};
+
+static inline struct tegra_dpaux *to_dpaux(struct drm_dp_aux *aux)
+{
+	return container_of(aux, struct tegra_dpaux, aux);
+}
+
+static inline unsigned long tegra_dpaux_readl(struct tegra_dpaux *dpaux,
+					      unsigned long offset)
+{
+	return readl(dpaux->regs + (offset << 2));
+}
+
+static inline void tegra_dpaux_writel(struct tegra_dpaux *dpaux,
+				      unsigned long value,
+				      unsigned long offset)
+{
+	writel(value, dpaux->regs + (offset << 2));
+}
+
+static void tegra_dpaux_write_fifo(struct tegra_dpaux *dpaux, const u8 *buffer,
+				   size_t size)
+{
+	unsigned long offset = DPAUX_DP_AUXDATA_WRITE(0);
+	size_t i, j;
+
+	for (i = 0; i < size; i += 4) {
+		size_t num = min_t(size_t, size - i, 4);
+		unsigned long value = 0;
+
+		for (j = 0; j < num; j++)
+			value |= buffer[i + j] << (j * 8);
+
+		tegra_dpaux_writel(dpaux, value, offset++);
+	}
+}
+
+static void tegra_dpaux_read_fifo(struct tegra_dpaux *dpaux, u8 *buffer,
+				  size_t size)
+{
+	unsigned long offset = DPAUX_DP_AUXDATA_READ(0);
+	size_t i, j;
+
+	for (i = 0; i < size; i += 4) {
+		size_t num = min_t(size_t, size - i, 4);
+		unsigned long value;
+
+		value = tegra_dpaux_readl(dpaux, offset++);
+
+		for (j = 0; j < num; j++)
+			buffer[i + j] = value >> (j * 8);
+	}
+}
+
+static ssize_t tegra_dpaux_transfer(struct drm_dp_aux *aux,
+				    struct drm_dp_aux_msg *msg)
+{
+	unsigned long value = DPAUX_DP_AUXCTL_TRANSACTREQ;
+	unsigned long timeout = msecs_to_jiffies(250);
+	struct tegra_dpaux *dpaux = to_dpaux(aux);
+	unsigned long status;
+	ssize_t ret = 0;
+
+	if (msg->size < 1 || msg->size > 16)
+		return -EINVAL;
+
+	tegra_dpaux_writel(dpaux, msg->address, DPAUX_DP_AUXADDR);
+
+	switch (msg->request & ~DP_AUX_I2C_MOT) {
+	case DP_AUX_I2C_WRITE:
+		if (msg->request & DP_AUX_I2C_MOT)
+			value = DPAUX_DP_AUXCTL_CMD_MOT_WR;
+		else
+			value = DPAUX_DP_AUXCTL_CMD_I2C_WR;
+
+		break;
+
+	case DP_AUX_I2C_READ:
+		if (msg->request & DP_AUX_I2C_MOT)
+			value = DPAUX_DP_AUXCTL_CMD_MOT_RD;
+		else
+			value = DPAUX_DP_AUXCTL_CMD_I2C_RD;
+
+		break;
+
+	case DP_AUX_I2C_STATUS:
+		if (msg->request & DP_AUX_I2C_MOT)
+			value = DPAUX_DP_AUXCTL_CMD_MOT_RQ;
+		else
+			value = DPAUX_DP_AUXCTL_CMD_I2C_RQ;
+
+		break;
+
+	case DP_AUX_NATIVE_WRITE:
+		value = DPAUX_DP_AUXCTL_CMD_AUX_WR;
+		break;
+
+	case DP_AUX_NATIVE_READ:
+		value = DPAUX_DP_AUXCTL_CMD_AUX_RD;
+		break;
+
+	default:
+		return -EINVAL;
+	}
+
+	value |= DPAUX_DP_AUXCTL_CMDLEN(msg->size - 1);
+	tegra_dpaux_writel(dpaux, value, DPAUX_DP_AUXCTL);
+
+	if ((msg->request & DP_AUX_I2C_READ) == 0) {
+		tegra_dpaux_write_fifo(dpaux, msg->buffer, msg->size);
+		ret = msg->size;
+	}
+
+	/* start transaction */
+	value = tegra_dpaux_readl(dpaux, DPAUX_DP_AUXCTL);
+	value |= DPAUX_DP_AUXCTL_TRANSACTREQ;
+	tegra_dpaux_writel(dpaux, value, DPAUX_DP_AUXCTL);
+
+	status = wait_for_completion_timeout(&dpaux->complete, timeout);
+	if (!status)
+		return -ETIMEDOUT;
+
+	/* read status and clear errors */
+	value = tegra_dpaux_readl(dpaux, DPAUX_DP_AUXSTAT);
+	tegra_dpaux_writel(dpaux, 0xf00, DPAUX_DP_AUXSTAT);
+
+	if (value & DPAUX_DP_AUXSTAT_TIMEOUT_ERROR)
+		return -ETIMEDOUT;
+
+	if ((value & DPAUX_DP_AUXSTAT_RX_ERROR) ||
+	    (value & DPAUX_DP_AUXSTAT_SINKSTAT_ERROR) ||
+	    (value & DPAUX_DP_AUXSTAT_NO_STOP_ERROR))
+		return -EIO;
+
+	switch ((value & DPAUX_DP_AUXSTAT_REPLY_TYPE_MASK) >> 16) {
+	case 0x00:
+		msg->reply = DP_AUX_NATIVE_REPLY_ACK;
+		break;
+
+	case 0x01:
+		msg->reply = DP_AUX_NATIVE_REPLY_NACK;
+		break;
+
+	case 0x02:
+		msg->reply = DP_AUX_NATIVE_REPLY_DEFER;
+		break;
+
+	case 0x04:
+		msg->reply = DP_AUX_I2C_REPLY_NACK;
+		break;
+
+	case 0x08:
+		msg->reply = DP_AUX_I2C_REPLY_DEFER;
+		break;
+	}
+
+	if (msg->reply == DP_AUX_NATIVE_REPLY_ACK) {
+		if (msg->request & DP_AUX_I2C_READ) {
+			size_t count = value & DPAUX_DP_AUXSTAT_REPLY_MASK;
+
+			if (WARN_ON(count != msg->size))
+				count = min_t(size_t, count, msg->size);
+
+			tegra_dpaux_read_fifo(dpaux, msg->buffer, count);
+			ret = count;
+		}
+	}
+
+	return ret;
+}
+
+static irqreturn_t tegra_dpaux_irq(int irq, void *data)
+{
+	struct tegra_dpaux *dpaux = data;
+	irqreturn_t ret = IRQ_HANDLED;
+	unsigned long value;
+
+	/* clear interrupts */
+	value = tegra_dpaux_readl(dpaux, DPAUX_INTR_AUX);
+	tegra_dpaux_writel(dpaux, value, DPAUX_INTR_AUX);
+
+	if (value & DPAUX_INTR_PLUG_EVENT) {
+		if (dpaux->output) {
+			drm_helper_hpd_irq_event(dpaux->output->connector.dev);
+		}
+	}
+
+	if (value & DPAUX_INTR_UNPLUG_EVENT) {
+		if (dpaux->output)
+			drm_helper_hpd_irq_event(dpaux->output->connector.dev);
+	}
+
+	if (value & DPAUX_INTR_IRQ_EVENT) {
+		/* TODO: handle this */
+	}
+
+	if (value & DPAUX_INTR_AUX_DONE)
+		complete(&dpaux->complete);
+
+	return ret;
+}
+
+static int tegra_dpaux_probe(struct platform_device *pdev)
+{
+	struct tegra_dpaux *dpaux;
+	struct resource *regs;
+	unsigned long value;
+	int err;
+
+	dpaux = devm_kzalloc(&pdev->dev, sizeof(*dpaux), GFP_KERNEL);
+	if (!dpaux)
+		return -ENOMEM;
+
+	init_completion(&dpaux->complete);
+	INIT_LIST_HEAD(&dpaux->list);
+	dpaux->dev = &pdev->dev;
+
+	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	dpaux->regs = devm_ioremap_resource(&pdev->dev, regs);
+	if (IS_ERR(dpaux->regs))
+		return PTR_ERR(dpaux->regs);
+
+	dpaux->irq = platform_get_irq(pdev, 0);
+	if (dpaux->irq < 0) {
+		dev_err(&pdev->dev, "failed to get IRQ\n");
+		return -ENXIO;
+	}
+
+	dpaux->rst = devm_reset_control_get(&pdev->dev, "dpaux");
+	if (IS_ERR(dpaux->rst))
+		return PTR_ERR(dpaux->rst);
+
+	dpaux->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(dpaux->clk))
+		return PTR_ERR(dpaux->clk);
+
+	err = clk_prepare_enable(dpaux->clk);
+	if (err < 0)
+		return err;
+
+	reset_control_deassert(dpaux->rst);
+
+	dpaux->clk_parent = devm_clk_get(&pdev->dev, "parent");
+	if (IS_ERR(dpaux->clk_parent))
+		return PTR_ERR(dpaux->clk_parent);
+
+	err = clk_prepare_enable(dpaux->clk_parent);
+	if (err < 0)
+		return err;
+
+	err = clk_set_rate(dpaux->clk_parent, 270000000);
+	if (err < 0) {
+		dev_err(&pdev->dev, "failed to set clock to 270 MHz: %d\n",
+			err);
+		return err;
+	}
+
+	dpaux->vdd = devm_regulator_get(&pdev->dev, "vdd");
+	if (IS_ERR(dpaux->vdd))
+		return PTR_ERR(dpaux->vdd);
+
+	err = devm_request_irq(dpaux->dev, dpaux->irq, tegra_dpaux_irq, 0,
+			       dev_name(dpaux->dev), dpaux);
+	if (err < 0) {
+		dev_err(dpaux->dev, "failed to request IRQ#%u: %d\n",
+			dpaux->irq, err);
+		return err;
+	}
+
+	dpaux->aux.transfer = tegra_dpaux_transfer;
+	dpaux->aux.dev = &pdev->dev;
+
+	err = drm_dp_aux_register_i2c_bus(&dpaux->aux);
+	if (err < 0)
+		return err;
+
+	/* enable and clear all interrupts */
+	value = DPAUX_INTR_AUX_DONE | DPAUX_INTR_IRQ_EVENT |
+		DPAUX_INTR_UNPLUG_EVENT | DPAUX_INTR_PLUG_EVENT;
+	tegra_dpaux_writel(dpaux, value, DPAUX_INTR_EN_AUX);
+	tegra_dpaux_writel(dpaux, value, DPAUX_INTR_AUX);
+
+	mutex_lock(&dpaux_lock);
+	list_add_tail(&dpaux->list, &dpaux_list);
+	mutex_unlock(&dpaux_lock);
+
+	platform_set_drvdata(pdev, dpaux);
+
+	return 0;
+}
+
+static int tegra_dpaux_remove(struct platform_device *pdev)
+{
+	struct tegra_dpaux *dpaux = platform_get_drvdata(pdev);
+
+	drm_dp_aux_unregister_i2c_bus(&dpaux->aux);
+
+	mutex_lock(&dpaux_lock);
+	list_del(&dpaux->list);
+	mutex_unlock(&dpaux_lock);
+
+	clk_disable_unprepare(dpaux->clk_parent);
+	reset_control_assert(dpaux->rst);
+	clk_disable_unprepare(dpaux->clk);
+
+	return 0;
+}
+
+static const struct of_device_id tegra_dpaux_of_match[] = {
+	{ .compatible = "nvidia,tegra124-dpaux", },
+	{ },
+};
+
+struct platform_driver tegra_dpaux_driver = {
+	.driver = {
+		.name = "tegra-dpaux",
+		.of_match_table = tegra_dpaux_of_match,
+	},
+	.probe = tegra_dpaux_probe,
+	.remove = tegra_dpaux_remove,
+};
+
+struct tegra_dpaux *tegra_dpaux_find_by_of_node(struct device_node *np)
+{
+	struct tegra_dpaux *dpaux;
+
+	mutex_lock(&dpaux_lock);
+
+	list_for_each_entry(dpaux, &dpaux_list, list)
+		if (np == dpaux->dev->of_node) {
+			mutex_unlock(&dpaux_lock);
+			return dpaux;
+		}
+
+	mutex_unlock(&dpaux_lock);
+
+	return NULL;
+}
+
+int tegra_dpaux_attach(struct tegra_dpaux *dpaux, struct tegra_output *output)
+{
+	unsigned long timeout;
+	int err;
+
+	dpaux->output = output;
+
+	err = regulator_enable(dpaux->vdd);
+	if (err < 0)
+		return err;
+
+	timeout = jiffies + msecs_to_jiffies(250);
+
+	while (time_before(jiffies, timeout)) {
+		enum drm_connector_status status;
+
+		status = tegra_dpaux_detect(dpaux);
+		if (status == connector_status_connected)
+			return 0;
+
+		usleep_range(1000, 2000);
+	}
+
+	return -ETIMEDOUT;
+}
+
+int tegra_dpaux_detach(struct tegra_dpaux *dpaux)
+{
+	unsigned long timeout;
+	int err;
+
+	err = regulator_disable(dpaux->vdd);
+	if (err < 0)
+		return err;
+
+	timeout = jiffies + msecs_to_jiffies(250);
+
+	while (time_before(jiffies, timeout)) {
+		enum drm_connector_status status;
+
+		status = tegra_dpaux_detect(dpaux);
+		if (status == connector_status_disconnected) {
+			dpaux->output = NULL;
+			return 0;
+		}
+
+		usleep_range(1000, 2000);
+	}
+
+	return -ETIMEDOUT;
+}
+
+enum drm_connector_status tegra_dpaux_detect(struct tegra_dpaux *dpaux)
+{
+	unsigned long value;
+
+	value = tegra_dpaux_readl(dpaux, DPAUX_DP_AUXSTAT);
+
+	if (value & DPAUX_DP_AUXSTAT_HPD_STATUS)
+		return connector_status_connected;
+
+	return connector_status_disconnected;
+}
+
+int tegra_dpaux_enable(struct tegra_dpaux *dpaux)
+{
+	unsigned long value;
+
+	value = DPAUX_HYBRID_PADCTL_AUX_CMH(2) |
+		DPAUX_HYBRID_PADCTL_AUX_DRVZ(4) |
+		DPAUX_HYBRID_PADCTL_AUX_DRVI(0x18) |
+		DPAUX_HYBRID_PADCTL_AUX_INPUT_RCV |
+		DPAUX_HYBRID_PADCTL_MODE_AUX;
+	tegra_dpaux_writel(dpaux, value, DPAUX_HYBRID_PADCTL);
+
+	value = tegra_dpaux_readl(dpaux, DPAUX_HYBRID_SPARE);
+	value &= ~DPAUX_HYBRID_SPARE_PAD_POWER_DOWN;
+	tegra_dpaux_writel(dpaux, value, DPAUX_HYBRID_SPARE);
+
+	return 0;
+}
+
+int tegra_dpaux_disable(struct tegra_dpaux *dpaux)
+{
+	unsigned long value;
+
+	value = tegra_dpaux_readl(dpaux, DPAUX_HYBRID_SPARE);
+	value |= DPAUX_HYBRID_SPARE_PAD_POWER_DOWN;
+	tegra_dpaux_writel(dpaux, value, DPAUX_HYBRID_SPARE);
+
+	return 0;
+}
+
+int tegra_dpaux_prepare(struct tegra_dpaux *dpaux, u8 encoding)
+{
+	int err;
+
+	err = drm_dp_dpcd_writeb(&dpaux->aux, DP_MAIN_LINK_CHANNEL_CODING_SET,
+				 encoding);
+	if (err < 0)
+		return err;
+
+	return 0;
+}
+
+int tegra_dpaux_train(struct tegra_dpaux *dpaux, struct drm_dp_link *link,
+		      u8 pattern)
+{
+	u8 tp = pattern & DP_TRAINING_PATTERN_MASK;
+	u8 status[DP_LINK_STATUS_SIZE], values[4];
+	unsigned int i;
+	int err;
+
+	err = drm_dp_dpcd_writeb(&dpaux->aux, DP_TRAINING_PATTERN_SET, pattern);
+	if (err < 0)
+		return err;
+
+	if (tp == DP_TRAINING_PATTERN_DISABLE)
+		return 0;
+
+	for (i = 0; i < link->num_lanes; i++)
+		values[i] = DP_TRAIN_MAX_PRE_EMPHASIS_REACHED |
+			    DP_TRAIN_PRE_EMPHASIS_0 |
+			    DP_TRAIN_MAX_SWING_REACHED |
+			    DP_TRAIN_VOLTAGE_SWING_400;
+
+	err = drm_dp_dpcd_write(&dpaux->aux, DP_TRAINING_LANE0_SET, values,
+				link->num_lanes);
+	if (err < 0)
+		return err;
+
+	usleep_range(500, 1000);
+
+	err = drm_dp_dpcd_read_link_status(&dpaux->aux, status);
+	if (err < 0)
+		return err;
+
+	switch (tp) {
+	case DP_TRAINING_PATTERN_1:
+		if (!drm_dp_clock_recovery_ok(status, link->num_lanes))
+			return -EAGAIN;
+
+		break;
+
+	case DP_TRAINING_PATTERN_2:
+		if (!drm_dp_channel_eq_ok(status, link->num_lanes))
+			return -EAGAIN;
+
+		break;
+
+	default:
+		dev_err(dpaux->dev, "unsupported training pattern %u\n", tp);
+		return -EINVAL;
+	}
+
+	err = drm_dp_dpcd_writeb(&dpaux->aux, DP_EDP_CONFIGURATION_SET, 0);
+	if (err < 0)
+		return err;
+
+	return 0;
+}