drivers/gpu/drm/bridge/simple-bridge.c - linux/torvalds/linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * Copyright (C) 2015-2016 Free Electrons
  * Copyright (C) 2015-2016 NextThing Co
  *
  * Maxime Ripard <maxime.ripard@free-electrons.com>
  */

 #include <linux/gpio/consumer.h>
 #include <linux/module.h>
 #include <linux/of_device.h>
 #include <linux/of_graph.h>
 #include <linux/regulator/consumer.h>

 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_bridge.h>
 #include <drm/drm_crtc.h>
 #include <drm/drm_print.h>
 #include <drm/drm_probe_helper.h>

 struct simple_bridge_info {
 	const struct drm_bridge_timings *timings;
 	unsigned int connector_type;
 };

 struct simple_bridge {
 	struct drm_bridge	bridge;
 	struct drm_connector	connector;

 	const struct simple_bridge_info *info;

 	struct i2c_adapter	*ddc;
 	struct regulator	*vdd;
 	struct gpio_desc	*enable;
 };

 static inline struct simple_bridge *
 drm_bridge_to_simple_bridge(struct drm_bridge *bridge)
 {
 	return container_of(bridge, struct simple_bridge, bridge);
 }

 static inline struct simple_bridge *
 drm_connector_to_simple_bridge(struct drm_connector *connector)
 {
 	return container_of(connector, struct simple_bridge, connector);
 }

 static int simple_bridge_get_modes(struct drm_connector *connector)
 {
 	struct simple_bridge *sbridge = drm_connector_to_simple_bridge(connector);
 	struct edid *edid;
 	int ret;

 	if (!sbridge->ddc)
 		goto fallback;

 	edid = drm_get_edid(connector, sbridge->ddc);
 	if (!edid) {
 		DRM_INFO("EDID readout failed, falling back to standard modes\n");
 		goto fallback;
 	}

 	drm_connector_update_edid_property(connector, edid);
 	ret = drm_add_edid_modes(connector, edid);
 	kfree(edid);
 	return ret;

 fallback:
 	/*
 	 * In case we cannot retrieve the EDIDs (broken or missing i2c
 	 * bus), fallback on the XGA standards
 	 */
 	ret = drm_add_modes_noedid(connector, 1920, 1200);

 	/* And prefer a mode pretty much anyone can handle */
 	drm_set_preferred_mode(connector, 1024, 768);

 	return ret;
 }

 static const struct drm_connector_helper_funcs simple_bridge_con_helper_funcs = {
 	.get_modes	= simple_bridge_get_modes,
 };

 static enum drm_connector_status
 simple_bridge_connector_detect(struct drm_connector *connector, bool force)
 {
 	struct simple_bridge *sbridge = drm_connector_to_simple_bridge(connector);

 	/*
 	 * Even if we have an I2C bus, we can't assume that the cable
 	 * is disconnected if drm_probe_ddc fails. Some cables don't
 	 * wire the DDC pins, or the I2C bus might not be working at
 	 * all.
 	 */
 	if (sbridge->ddc && drm_probe_ddc(sbridge->ddc))
 		return connector_status_connected;

 	return connector_status_unknown;
 }

 static const struct drm_connector_funcs simple_bridge_con_funcs = {
 	.detect			= simple_bridge_connector_detect,
 	.fill_modes		= drm_helper_probe_single_connector_modes,
 	.destroy		= drm_connector_cleanup,
 	.reset			= drm_atomic_helper_connector_reset,
 	.atomic_duplicate_state	= drm_atomic_helper_connector_duplicate_state,
 	.atomic_destroy_state	= drm_atomic_helper_connector_destroy_state,
 };

 static int simple_bridge_attach(struct drm_bridge *bridge,
 				enum drm_bridge_attach_flags flags)
 {
 	struct simple_bridge *sbridge = drm_bridge_to_simple_bridge(bridge);
 	int ret;

 	if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR) {
 		DRM_ERROR("Fix bridge driver to make connector optional!");
 		return -EINVAL;
 	}

 	if (!bridge->encoder) {
 		DRM_ERROR("Missing encoder\n");
 		return -ENODEV;
 	}

 	drm_connector_helper_add(&sbridge->connector,
 				 &simple_bridge_con_helper_funcs);
 	ret = drm_connector_init_with_ddc(bridge->dev, &sbridge->connector,
 					  &simple_bridge_con_funcs,
 					  sbridge->info->connector_type,
 					  sbridge->ddc);
 	if (ret) {
 		DRM_ERROR("Failed to initialize connector\n");
 		return ret;
 	}

 	drm_connector_attach_encoder(&sbridge->connector,
 					  bridge->encoder);

 	return 0;
 }

 static void simple_bridge_enable(struct drm_bridge *bridge)
 {
 	struct simple_bridge *sbridge = drm_bridge_to_simple_bridge(bridge);
 	int ret;

 	if (sbridge->vdd) {
 		ret = regulator_enable(sbridge->vdd);
 		if (ret)
 			DRM_ERROR("Failed to enable vdd regulator: %d\n", ret);
 	}

 	gpiod_set_value_cansleep(sbridge->enable, 1);
 }

 static void simple_bridge_disable(struct drm_bridge *bridge)
 {
 	struct simple_bridge *sbridge = drm_bridge_to_simple_bridge(bridge);

 	gpiod_set_value_cansleep(sbridge->enable, 0);

 	if (sbridge->vdd)
 		regulator_disable(sbridge->vdd);
 }

 static const struct drm_bridge_funcs simple_bridge_bridge_funcs = {
 	.attach		= simple_bridge_attach,
 	.enable		= simple_bridge_enable,
 	.disable	= simple_bridge_disable,
 };

 static struct i2c_adapter *simple_bridge_retrieve_ddc(struct device *dev)
 {
 	struct device_node *phandle, *remote;
 	struct i2c_adapter *ddc;

 	remote = of_graph_get_remote_node(dev->of_node, 1, -1);
 	if (!remote)
 		return ERR_PTR(-EINVAL);

 	phandle = of_parse_phandle(remote, "ddc-i2c-bus", 0);
 	of_node_put(remote);
 	if (!phandle)
 		return ERR_PTR(-ENODEV);

 	ddc = of_get_i2c_adapter_by_node(phandle);
 	of_node_put(phandle);
 	if (!ddc)
 		return ERR_PTR(-EPROBE_DEFER);

 	return ddc;
 }

 static int simple_bridge_probe(struct platform_device *pdev)
 {
 	struct simple_bridge *sbridge;

 	sbridge = devm_kzalloc(&pdev->dev, sizeof(*sbridge), GFP_KERNEL);
 	if (!sbridge)
 		return -ENOMEM;
 	platform_set_drvdata(pdev, sbridge);

 	sbridge->info = of_device_get_match_data(&pdev->dev);

 	sbridge->vdd = devm_regulator_get_optional(&pdev->dev, "vdd");
 	if (IS_ERR(sbridge->vdd)) {
 		int ret = PTR_ERR(sbridge->vdd);
 		if (ret == -EPROBE_DEFER)
 			return -EPROBE_DEFER;
 		sbridge->vdd = NULL;
 		dev_dbg(&pdev->dev, "No vdd regulator found: %d\n", ret);
 	}

 	sbridge->enable = devm_gpiod_get_optional(&pdev->dev, "enable",
 						  GPIOD_OUT_LOW);
 	if (IS_ERR(sbridge->enable)) {
 		if (PTR_ERR(sbridge->enable) != -EPROBE_DEFER)
 			dev_err(&pdev->dev, "Unable to retrieve enable GPIO\n");
 		return PTR_ERR(sbridge->enable);
 	}

 	sbridge->ddc = simple_bridge_retrieve_ddc(&pdev->dev);
 	if (IS_ERR(sbridge->ddc)) {
 		if (PTR_ERR(sbridge->ddc) == -ENODEV) {
 			dev_dbg(&pdev->dev,
 				"No i2c bus specified. Disabling EDID readout\n");
 			sbridge->ddc = NULL;
 		} else {
 			dev_err(&pdev->dev, "Couldn't retrieve i2c bus\n");
 			return PTR_ERR(sbridge->ddc);
 		}
 	}

 	sbridge->bridge.funcs = &simple_bridge_bridge_funcs;
 	sbridge->bridge.of_node = pdev->dev.of_node;
 	sbridge->bridge.timings = sbridge->info->timings;

 	drm_bridge_add(&sbridge->bridge);

 	return 0;
 }

 static int simple_bridge_remove(struct platform_device *pdev)
 {
 	struct simple_bridge *sbridge = platform_get_drvdata(pdev);

 	drm_bridge_remove(&sbridge->bridge);

 	if (sbridge->ddc)
 		i2c_put_adapter(sbridge->ddc);

 	return 0;
 }

 /*
  * We assume the ADV7123 DAC is the "default" for historical reasons
  * Information taken from the ADV7123 datasheet, revision D.
  * NOTE: the ADV7123EP seems to have other timings and need a new timings
  * set if used.
  */
 static const struct drm_bridge_timings default_bridge_timings = {
 	/* Timing specifications, datasheet page 7 */
 	.input_bus_flags = DRM_BUS_FLAG_PIXDATA_SAMPLE_POSEDGE,
 	.setup_time_ps = 500,
 	.hold_time_ps = 1500,
 };

 /*
  * Information taken from the THS8134, THS8134A, THS8134B datasheet named
  * "SLVS205D", dated May 1990, revised March 2000.
  */
 static const struct drm_bridge_timings ti_ths8134_bridge_timings = {
 	/* From timing diagram, datasheet page 9 */
 	.input_bus_flags = DRM_BUS_FLAG_PIXDATA_SAMPLE_POSEDGE,
 	/* From datasheet, page 12 */
 	.setup_time_ps = 3000,
 	/* I guess this means latched input */
 	.hold_time_ps = 0,
 };

 /*
  * Information taken from the THS8135 datasheet named "SLAS343B", dated
  * May 2001, revised April 2013.
  */
 static const struct drm_bridge_timings ti_ths8135_bridge_timings = {
 	/* From timing diagram, datasheet page 14 */
 	.input_bus_flags = DRM_BUS_FLAG_PIXDATA_SAMPLE_POSEDGE,
 	/* From datasheet, page 16 */
 	.setup_time_ps = 2000,
 	.hold_time_ps = 500,
 };

 static const struct of_device_id simple_bridge_match[] = {
 	{
 		.compatible = "dumb-vga-dac",
 		.data = &(const struct simple_bridge_info) {
 			.connector_type = DRM_MODE_CONNECTOR_VGA,
 		},
 	}, {
 		.compatible = "adi,adv7123",
 		.data = &(const struct simple_bridge_info) {
 			.timings = &default_bridge_timings,
 			.connector_type = DRM_MODE_CONNECTOR_VGA,
 		},
 	}, {
 		.compatible = "ti,opa362",
 		.data = &(const struct simple_bridge_info) {
 			.connector_type = DRM_MODE_CONNECTOR_Composite,
 		},
 	}, {
 		.compatible = "ti,ths8135",
 		.data = &(const struct simple_bridge_info) {
 			.timings = &ti_ths8135_bridge_timings,
 			.connector_type = DRM_MODE_CONNECTOR_VGA,
 		},
 	}, {
 		.compatible = "ti,ths8134",
 		.data = &(const struct simple_bridge_info) {
 			.timings = &ti_ths8134_bridge_timings,
 			.connector_type = DRM_MODE_CONNECTOR_VGA,
 		},
 	},
 	{},
 };
 MODULE_DEVICE_TABLE(of, simple_bridge_match);

 static struct platform_driver simple_bridge_driver = {
 	.probe	= simple_bridge_probe,
 	.remove	= simple_bridge_remove,
 	.driver		= {
 		.name		= "simple-bridge",
 		.of_match_table	= simple_bridge_match,
 	},
 };
 module_platform_driver(simple_bridge_driver);

 MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
 MODULE_DESCRIPTION("Simple DRM bridge driver");
 MODULE_LICENSE("GPL");
	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	* Copyright (C) 2015-2016 Free Electrons
	* Copyright (C) 2015-2016 NextThing Co
	*
	* Maxime Ripard <maxime.ripard@free-electrons.com>
	*/

	#include <linux/gpio/consumer.h>
	#include <linux/module.h>
	#include <linux/of_device.h>
	#include <linux/of_graph.h>
	#include <linux/regulator/consumer.h>

	#include <drm/drm_atomic_helper.h>
	#include <drm/drm_bridge.h>
	#include <drm/drm_crtc.h>
	#include <drm/drm_print.h>
	#include <drm/drm_probe_helper.h>

	struct simple_bridge_info {
	const struct drm_bridge_timings *timings;
	unsigned int connector_type;
	};

	struct simple_bridge {
	struct drm_bridge bridge;
	struct drm_connector connector;

	const struct simple_bridge_info *info;

	struct i2c_adapter *ddc;
	struct regulator *vdd;
	struct gpio_desc *enable;
	};

	static inline struct simple_bridge *
	drm_bridge_to_simple_bridge(struct drm_bridge *bridge)
	{
	return container_of(bridge, struct simple_bridge, bridge);
	}

	static inline struct simple_bridge *
	drm_connector_to_simple_bridge(struct drm_connector *connector)
	{
	return container_of(connector, struct simple_bridge, connector);
	}

	static int simple_bridge_get_modes(struct drm_connector *connector)
	{
	struct simple_bridge *sbridge = drm_connector_to_simple_bridge(connector);
	struct edid *edid;
	int ret;

	if (!sbridge->ddc)
	goto fallback;

	edid = drm_get_edid(connector, sbridge->ddc);
	if (!edid) {
	DRM_INFO("EDID readout failed, falling back to standard modes\n");
	goto fallback;
	}

	drm_connector_update_edid_property(connector, edid);
	ret = drm_add_edid_modes(connector, edid);
	kfree(edid);
	return ret;

	fallback:
	/*
	* In case we cannot retrieve the EDIDs (broken or missing i2c
	* bus), fallback on the XGA standards
	*/
	ret = drm_add_modes_noedid(connector, 1920, 1200);

	/* And prefer a mode pretty much anyone can handle */
	drm_set_preferred_mode(connector, 1024, 768);

	return ret;
	}

	static const struct drm_connector_helper_funcs simple_bridge_con_helper_funcs = {
	.get_modes = simple_bridge_get_modes,
	};

	static enum drm_connector_status
	simple_bridge_connector_detect(struct drm_connector *connector, bool force)
	{
	struct simple_bridge *sbridge = drm_connector_to_simple_bridge(connector);

	/*
	* Even if we have an I2C bus, we can't assume that the cable
	* is disconnected if drm_probe_ddc fails. Some cables don't
	* wire the DDC pins, or the I2C bus might not be working at
	* all.
	*/
	if (sbridge->ddc && drm_probe_ddc(sbridge->ddc))
	return connector_status_connected;

	return connector_status_unknown;
	}

	static const struct drm_connector_funcs simple_bridge_con_funcs = {
	.detect = simple_bridge_connector_detect,
	.fill_modes = drm_helper_probe_single_connector_modes,
	.destroy = drm_connector_cleanup,
	.reset = drm_atomic_helper_connector_reset,
	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
	};

	static int simple_bridge_attach(struct drm_bridge *bridge,
	enum drm_bridge_attach_flags flags)
	{
	struct simple_bridge *sbridge = drm_bridge_to_simple_bridge(bridge);
	int ret;

	if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR) {
	DRM_ERROR("Fix bridge driver to make connector optional!");
	return -EINVAL;
	}

	if (!bridge->encoder) {
	DRM_ERROR("Missing encoder\n");
	return -ENODEV;
	}

	drm_connector_helper_add(&sbridge->connector,
	&simple_bridge_con_helper_funcs);
	ret = drm_connector_init_with_ddc(bridge->dev, &sbridge->connector,
	&simple_bridge_con_funcs,
	sbridge->info->connector_type,
	sbridge->ddc);
	if (ret) {
	DRM_ERROR("Failed to initialize connector\n");
	return ret;
	}

	drm_connector_attach_encoder(&sbridge->connector,
	bridge->encoder);

	return 0;
	}

	static void simple_bridge_enable(struct drm_bridge *bridge)
	{
	struct simple_bridge *sbridge = drm_bridge_to_simple_bridge(bridge);
	int ret;

	if (sbridge->vdd) {
	ret = regulator_enable(sbridge->vdd);
	if (ret)
	DRM_ERROR("Failed to enable vdd regulator: %d\n", ret);
	}

	gpiod_set_value_cansleep(sbridge->enable, 1);
	}

	static void simple_bridge_disable(struct drm_bridge *bridge)
	{
	struct simple_bridge *sbridge = drm_bridge_to_simple_bridge(bridge);

	gpiod_set_value_cansleep(sbridge->enable, 0);

	if (sbridge->vdd)
	regulator_disable(sbridge->vdd);
	}

	static const struct drm_bridge_funcs simple_bridge_bridge_funcs = {
	.attach = simple_bridge_attach,
	.enable = simple_bridge_enable,
	.disable = simple_bridge_disable,
	};

	static struct i2c_adapter simple_bridge_retrieve_ddc(struct device dev)
	{
	struct device_node phandle, remote;
	struct i2c_adapter *ddc;

	remote = of_graph_get_remote_node(dev->of_node, 1, -1);
	if (!remote)
	return ERR_PTR(-EINVAL);

	phandle = of_parse_phandle(remote, "ddc-i2c-bus", 0);
	of_node_put(remote);
	if (!phandle)
	return ERR_PTR(-ENODEV);

	ddc = of_get_i2c_adapter_by_node(phandle);
	of_node_put(phandle);
	if (!ddc)
	return ERR_PTR(-EPROBE_DEFER);

	return ddc;
	}

	static int simple_bridge_probe(struct platform_device *pdev)
	{
	struct simple_bridge *sbridge;

	sbridge = devm_kzalloc(&pdev->dev, sizeof(*sbridge), GFP_KERNEL);
	if (!sbridge)
	return -ENOMEM;
	platform_set_drvdata(pdev, sbridge);

	sbridge->info = of_device_get_match_data(&pdev->dev);

	sbridge->vdd = devm_regulator_get_optional(&pdev->dev, "vdd");
	if (IS_ERR(sbridge->vdd)) {
	int ret = PTR_ERR(sbridge->vdd);
	if (ret == -EPROBE_DEFER)
	return -EPROBE_DEFER;
	sbridge->vdd = NULL;
	dev_dbg(&pdev->dev, "No vdd regulator found: %d\n", ret);
	}

	sbridge->enable = devm_gpiod_get_optional(&pdev->dev, "enable",
	GPIOD_OUT_LOW);
	if (IS_ERR(sbridge->enable)) {
	if (PTR_ERR(sbridge->enable) != -EPROBE_DEFER)
	dev_err(&pdev->dev, "Unable to retrieve enable GPIO\n");
	return PTR_ERR(sbridge->enable);
	}

	sbridge->ddc = simple_bridge_retrieve_ddc(&pdev->dev);
	if (IS_ERR(sbridge->ddc)) {
	if (PTR_ERR(sbridge->ddc) == -ENODEV) {
	dev_dbg(&pdev->dev,
	"No i2c bus specified. Disabling EDID readout\n");
	sbridge->ddc = NULL;
	} else {
	dev_err(&pdev->dev, "Couldn't retrieve i2c bus\n");
	return PTR_ERR(sbridge->ddc);
	}
	}

	sbridge->bridge.funcs = &simple_bridge_bridge_funcs;
	sbridge->bridge.of_node = pdev->dev.of_node;
	sbridge->bridge.timings = sbridge->info->timings;

	drm_bridge_add(&sbridge->bridge);

	return 0;
	}

	static int simple_bridge_remove(struct platform_device *pdev)
	{
	struct simple_bridge *sbridge = platform_get_drvdata(pdev);

	drm_bridge_remove(&sbridge->bridge);

	if (sbridge->ddc)
	i2c_put_adapter(sbridge->ddc);

	return 0;
	}

	/*
	* We assume the ADV7123 DAC is the "default" for historical reasons
	* Information taken from the ADV7123 datasheet, revision D.
	* NOTE: the ADV7123EP seems to have other timings and need a new timings
	* set if used.
	*/
	static const struct drm_bridge_timings default_bridge_timings = {
	/* Timing specifications, datasheet page 7 */
	.input_bus_flags = DRM_BUS_FLAG_PIXDATA_SAMPLE_POSEDGE,
	.setup_time_ps = 500,
	.hold_time_ps = 1500,
	};

	/*
	* Information taken from the THS8134, THS8134A, THS8134B datasheet named
	* "SLVS205D", dated May 1990, revised March 2000.
	*/
	static const struct drm_bridge_timings ti_ths8134_bridge_timings = {
	/* From timing diagram, datasheet page 9 */
	.input_bus_flags = DRM_BUS_FLAG_PIXDATA_SAMPLE_POSEDGE,
	/* From datasheet, page 12 */
	.setup_time_ps = 3000,
	/* I guess this means latched input */
	.hold_time_ps = 0,
	};

	/*
	* Information taken from the THS8135 datasheet named "SLAS343B", dated
	* May 2001, revised April 2013.
	*/
	static const struct drm_bridge_timings ti_ths8135_bridge_timings = {
	/* From timing diagram, datasheet page 14 */
	.input_bus_flags = DRM_BUS_FLAG_PIXDATA_SAMPLE_POSEDGE,
	/* From datasheet, page 16 */
	.setup_time_ps = 2000,
	.hold_time_ps = 500,
	};

	static const struct of_device_id simple_bridge_match[] = {
	{
	.compatible = "dumb-vga-dac",
	.data = &(const struct simple_bridge_info) {
	.connector_type = DRM_MODE_CONNECTOR_VGA,
	},
	}, {
	.compatible = "adi,adv7123",
	.data = &(const struct simple_bridge_info) {
	.timings = &default_bridge_timings,
	.connector_type = DRM_MODE_CONNECTOR_VGA,
	},
	}, {
	.compatible = "ti,opa362",
	.data = &(const struct simple_bridge_info) {
	.connector_type = DRM_MODE_CONNECTOR_Composite,
	},
	}, {
	.compatible = "ti,ths8135",
	.data = &(const struct simple_bridge_info) {
	.timings = &ti_ths8135_bridge_timings,
	.connector_type = DRM_MODE_CONNECTOR_VGA,
	},
	}, {
	.compatible = "ti,ths8134",
	.data = &(const struct simple_bridge_info) {
	.timings = &ti_ths8134_bridge_timings,
	.connector_type = DRM_MODE_CONNECTOR_VGA,
	},
	},
	{},
	};
	MODULE_DEVICE_TABLE(of, simple_bridge_match);

	static struct platform_driver simple_bridge_driver = {
	.probe = simple_bridge_probe,
	.remove = simple_bridge_remove,
	.driver = {
	.name = "simple-bridge",
	.of_match_table = simple_bridge_match,
	},
	};
	module_platform_driver(simple_bridge_driver);

	MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
	MODULE_DESCRIPTION("Simple DRM bridge driver");
	MODULE_LICENSE("GPL");