drm: Add support of ARC PGU display controller

ARC PGU could be found on some development boards from Synopsys.
This is a simple byte streamer that reads data from a framebuffer
and sends data to the single encoder.

Signed-off-by: Carlos Palminha <palminha@synopsys.com>
Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
Cc: David Airlie <airlied@linux.ie>
Cc: dri-devel@lists.freedesktop.org
Cc: linux-snps-arc@lists.infradead.org

drivers/gpu/drm/arc/arcpgu_hdmi.c

@@ -0,0 +1,201 @@
+/*
+ * ARC PGU DRM driver.
+ *
+ * Copyright (C) 2016 Synopsys, Inc. (www.synopsys.com)
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <drm/drm_crtc_helper.h>
+#include <drm/drm_encoder_slave.h>
+#include <drm/drm_atomic_helper.h>
+
+#include "arcpgu.h"
+
+struct arcpgu_drm_connector {
+	struct drm_connector connector;
+	struct drm_encoder_slave *encoder_slave;
+};
+
+static int arcpgu_drm_connector_get_modes(struct drm_connector *connector)
+{
+	const struct drm_encoder_slave_funcs *sfuncs;
+	struct drm_encoder_slave *slave;
+	struct arcpgu_drm_connector *con =
+		container_of(connector, struct arcpgu_drm_connector, connector);
+
+	slave = con->encoder_slave;
+	if (slave == NULL) {
+		dev_err(connector->dev->dev,
+			"connector_get_modes: cannot find slave encoder for connector\n");
+		return 0;
+	}
+
+	sfuncs = slave->slave_funcs;
+	if (sfuncs->get_modes == NULL)
+		return 0;
+
+	return sfuncs->get_modes(&slave->base, connector);
+}
+
+struct drm_encoder *
+arcpgu_drm_connector_best_encoder(struct drm_connector *connector)
+{
+	struct drm_encoder_slave *slave;
+	struct arcpgu_drm_connector *con =
+		container_of(connector, struct arcpgu_drm_connector, connector);
+
+	slave = con->encoder_slave;
+	if (slave == NULL) {
+		dev_err(connector->dev->dev,
+			"connector_best_encoder: cannot find slave encoder for connector\n");
+		return NULL;
+	}
+
+	return &slave->base;
+}
+
+static enum drm_connector_status
+arcpgu_drm_connector_detect(struct drm_connector *connector, bool force)
+{
+	enum drm_connector_status status = connector_status_unknown;
+	const struct drm_encoder_slave_funcs *sfuncs;
+	struct drm_encoder_slave *slave;
+
+	struct arcpgu_drm_connector *con =
+		container_of(connector, struct arcpgu_drm_connector, connector);
+
+	slave = con->encoder_slave;
+	if (slave == NULL) {
+		dev_err(connector->dev->dev,
+			"connector_detect: cannot find slave encoder for connector\n");
+		return status;
+	}
+
+	sfuncs = slave->slave_funcs;
+	if (sfuncs && sfuncs->detect)
+		return sfuncs->detect(&slave->base, connector);
+
+	dev_err(connector->dev->dev, "connector_detect: could not detect slave funcs\n");
+	return status;
+}
+
+static void arcpgu_drm_connector_destroy(struct drm_connector *connector)
+{
+	drm_connector_unregister(connector);
+	drm_connector_cleanup(connector);
+}
+
+static const struct drm_connector_helper_funcs
+arcpgu_drm_connector_helper_funcs = {
+	.get_modes = arcpgu_drm_connector_get_modes,
+	.best_encoder = arcpgu_drm_connector_best_encoder,
+};
+
+static const struct drm_connector_funcs arcpgu_drm_connector_funcs = {
+	.dpms = drm_helper_connector_dpms,
+	.reset = drm_atomic_helper_connector_reset,
+	.detect = arcpgu_drm_connector_detect,
+	.fill_modes = drm_helper_probe_single_connector_modes,
+	.destroy = arcpgu_drm_connector_destroy,
+	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
+	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
+};
+
+static struct drm_encoder_helper_funcs arcpgu_drm_encoder_helper_funcs = {
+	.dpms = drm_i2c_encoder_dpms,
+	.mode_fixup = drm_i2c_encoder_mode_fixup,
+	.mode_set = drm_i2c_encoder_mode_set,
+	.prepare = drm_i2c_encoder_prepare,
+	.commit = drm_i2c_encoder_commit,
+	.detect = drm_i2c_encoder_detect,
+};
+
+static struct drm_encoder_funcs arcpgu_drm_encoder_funcs = {
+	.destroy = drm_encoder_cleanup,
+};
+
+int arcpgu_drm_hdmi_init(struct drm_device *drm, struct device_node *np)
+{
+	struct arcpgu_drm_connector *arcpgu_connector;
+	struct drm_i2c_encoder_driver *driver;
+	struct drm_encoder_slave *encoder;
+	struct drm_connector *connector;
+	struct i2c_client *i2c_slave;
+	int ret;
+
+	encoder = devm_kzalloc(drm->dev, sizeof(*encoder), GFP_KERNEL);
+	if (encoder == NULL)
+		return -ENOMEM;
+
+	i2c_slave = of_find_i2c_device_by_node(np);
+	if (!i2c_slave || !i2c_get_clientdata(i2c_slave)) {
+		dev_err(drm->dev, "failed to find i2c slave encoder\n");
+		return -EPROBE_DEFER;
+	}
+
+	if (i2c_slave->dev.driver == NULL) {
+		dev_err(drm->dev, "failed to find i2c slave driver\n");
+		return -EPROBE_DEFER;
+	}
+
+	driver =
+	    to_drm_i2c_encoder_driver(to_i2c_driver(i2c_slave->dev.driver));
+	ret = driver->encoder_init(i2c_slave, drm, encoder);
+	if (ret) {
+		dev_err(drm->dev, "failed to initialize i2c encoder slave\n");
+		return ret;
+	}
+
+	encoder->base.possible_crtcs = 1;
+	encoder->base.possible_clones = 0;
+	ret = drm_encoder_init(drm, &encoder->base, &arcpgu_drm_encoder_funcs,
+			       DRM_MODE_ENCODER_TMDS, NULL);
+	if (ret)
+		return ret;
+
+	drm_encoder_helper_add(&encoder->base,
+			       &arcpgu_drm_encoder_helper_funcs);
+
+	arcpgu_connector = devm_kzalloc(drm->dev, sizeof(*arcpgu_connector),
+					GFP_KERNEL);
+	if (!arcpgu_connector) {
+		ret = -ENOMEM;
+		goto error_encoder_cleanup;
+	}
+
+	connector = &arcpgu_connector->connector;
+	drm_connector_helper_add(connector, &arcpgu_drm_connector_helper_funcs);
+	ret = drm_connector_init(drm, connector, &arcpgu_drm_connector_funcs,
+			DRM_MODE_CONNECTOR_HDMIA);
+	if (ret < 0) {
+		dev_err(drm->dev, "failed to initialize drm connector\n");
+		goto error_encoder_cleanup;
+	}
+
+	ret = drm_mode_connector_attach_encoder(connector, &encoder->base);
+	if (ret < 0) {
+		dev_err(drm->dev, "could not attach connector to encoder\n");
+		drm_connector_unregister(connector);
+		goto error_connector_cleanup;
+	}
+
+	arcpgu_connector->encoder_slave = encoder;
+
+	return 0;
+
+error_connector_cleanup:
+	drm_connector_cleanup(connector);
+
+error_encoder_cleanup:
+	drm_encoder_cleanup(&encoder->base);
+	return ret;
+}