drivers/gpu/drm/tilcdc/tilcdc_slave.c - arm/linux-arm64-legacy - Git at Google

 /*
  * Copyright (C) 2012 Texas Instruments
  * Author: Rob Clark <robdclark@gmail.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.
  *
  * You should have received a copy of the GNU General Public License along with
  * this program.  If not, see <http://www.gnu.org/licenses/>.
  */

 #include <linux/i2c.h>
 #include <linux/pinctrl/pinmux.h>
 #include <linux/pinctrl/consumer.h>
 #include <drm/drm_encoder_slave.h>

 #include "tilcdc_drv.h"

 struct slave_module {
 	struct tilcdc_module base;
 	struct i2c_adapter *i2c;
 };
 #define to_slave_module(x) container_of(x, struct slave_module, base)

 static const struct tilcdc_panel_info slave_info = {
 		.bpp                    = 16,
 		.ac_bias                = 255,
 		.ac_bias_intrpt         = 0,
 		.dma_burst_sz           = 16,
 		.fdd                    = 0x80,
 		.tft_alt_mode           = 0,
 		.sync_edge              = 0,
 		.sync_ctrl              = 1,
 		.raster_order           = 0,
 };


 /*
  * Encoder:
  */

 struct slave_encoder {
 	struct drm_encoder_slave base;
 	struct slave_module *mod;
 };
 #define to_slave_encoder(x) container_of(to_encoder_slave(x), struct slave_encoder, base)

 static inline struct drm_encoder_slave_funcs *
 get_slave_funcs(struct drm_encoder *enc)
 {
 	return to_encoder_slave(enc)->slave_funcs;
 }

 static void slave_encoder_destroy(struct drm_encoder *encoder)
 {
 	struct slave_encoder *slave_encoder = to_slave_encoder(encoder);
 	if (get_slave_funcs(encoder))
 		get_slave_funcs(encoder)->destroy(encoder);
 	drm_encoder_cleanup(encoder);
 	kfree(slave_encoder);
 }

 static void slave_encoder_prepare(struct drm_encoder *encoder)
 {
 	drm_i2c_encoder_prepare(encoder);
 	tilcdc_crtc_set_panel_info(encoder->crtc, &slave_info);
 }

 static bool slave_encoder_fixup(struct drm_encoder *encoder,
 		const struct drm_display_mode *mode,
 		struct drm_display_mode *adjusted_mode)
 {
 	/*
 	 * tilcdc does not generate VESA-complient sync but aligns
 	 * VS on the second edge of HS instead of first edge.
 	 * We use adjusted_mode, to fixup sync by aligning both rising
 	 * edges and add HSKEW offset to let the slave encoder fix it up.
 	 */
 	adjusted_mode->hskew = mode->hsync_end - mode->hsync_start;
 	adjusted_mode->flags |= DRM_MODE_FLAG_HSKEW;

 	if (mode->flags & DRM_MODE_FLAG_NHSYNC) {
 		adjusted_mode->flags |= DRM_MODE_FLAG_PHSYNC;
 		adjusted_mode->flags &= ~DRM_MODE_FLAG_NHSYNC;
 	} else {
 		adjusted_mode->flags |= DRM_MODE_FLAG_NHSYNC;
 		adjusted_mode->flags &= ~DRM_MODE_FLAG_PHSYNC;
 	}

 	return drm_i2c_encoder_mode_fixup(encoder, mode, adjusted_mode);
 }


 static const struct drm_encoder_funcs slave_encoder_funcs = {
 		.destroy        = slave_encoder_destroy,
 };

 static const struct drm_encoder_helper_funcs slave_encoder_helper_funcs = {
 		.dpms           = drm_i2c_encoder_dpms,
 		.mode_fixup     = slave_encoder_fixup,
 		.prepare        = slave_encoder_prepare,
 		.commit         = drm_i2c_encoder_commit,
 		.mode_set       = drm_i2c_encoder_mode_set,
 		.save           = drm_i2c_encoder_save,
 		.restore        = drm_i2c_encoder_restore,
 };

 static const struct i2c_board_info info = {
 		I2C_BOARD_INFO("tda998x", 0x70)
 };

 static struct drm_encoder *slave_encoder_create(struct drm_device *dev,
 		struct slave_module *mod)
 {
 	struct slave_encoder *slave_encoder;
 	struct drm_encoder *encoder;
 	int ret;

 	slave_encoder = kzalloc(sizeof(*slave_encoder), GFP_KERNEL);
 	if (!slave_encoder) {
 		dev_err(dev->dev, "allocation failed\n");
 		return NULL;
 	}

 	slave_encoder->mod = mod;

 	encoder = &slave_encoder->base.base;
 	encoder->possible_crtcs = 1;

 	ret = drm_encoder_init(dev, encoder, &slave_encoder_funcs,
 			DRM_MODE_ENCODER_TMDS);
 	if (ret)
 		goto fail;

 	drm_encoder_helper_add(encoder, &slave_encoder_helper_funcs);

 	ret = drm_i2c_encoder_init(dev, to_encoder_slave(encoder), mod->i2c, &info);
 	if (ret)
 		goto fail;

 	return encoder;

 fail:
 	slave_encoder_destroy(encoder);
 	return NULL;
 }

 /*
  * Connector:
  */

 struct slave_connector {
 	struct drm_connector base;

 	struct drm_encoder *encoder;  /* our connected encoder */
 	struct slave_module *mod;
 };
 #define to_slave_connector(x) container_of(x, struct slave_connector, base)

 static void slave_connector_destroy(struct drm_connector *connector)
 {
 	struct slave_connector *slave_connector = to_slave_connector(connector);
 	drm_connector_cleanup(connector);
 	kfree(slave_connector);
 }

 static enum drm_connector_status slave_connector_detect(
 		struct drm_connector *connector,
 		bool force)
 {
 	struct drm_encoder *encoder = to_slave_connector(connector)->encoder;
 	return get_slave_funcs(encoder)->detect(encoder, connector);
 }

 static int slave_connector_get_modes(struct drm_connector *connector)
 {
 	struct drm_encoder *encoder = to_slave_connector(connector)->encoder;
 	return get_slave_funcs(encoder)->get_modes(encoder, connector);
 }

 static int slave_connector_mode_valid(struct drm_connector *connector,
 		  struct drm_display_mode *mode)
 {
 	struct drm_encoder *encoder = to_slave_connector(connector)->encoder;
 	struct tilcdc_drm_private *priv = connector->dev->dev_private;
 	int ret;

 	ret = tilcdc_crtc_mode_valid(priv->crtc, mode);
 	if (ret != MODE_OK)
 		return ret;

 	return get_slave_funcs(encoder)->mode_valid(encoder, mode);
 }

 static struct drm_encoder *slave_connector_best_encoder(
 		struct drm_connector *connector)
 {
 	struct slave_connector *slave_connector = to_slave_connector(connector);
 	return slave_connector->encoder;
 }

 static int slave_connector_set_property(struct drm_connector *connector,
 		struct drm_property *property, uint64_t value)
 {
 	struct drm_encoder *encoder = to_slave_connector(connector)->encoder;
 	return get_slave_funcs(encoder)->set_property(encoder,
 			connector, property, value);
 }

 static const struct drm_connector_funcs slave_connector_funcs = {
 	.destroy            = slave_connector_destroy,
 	.dpms               = drm_helper_connector_dpms,
 	.detect             = slave_connector_detect,
 	.fill_modes         = drm_helper_probe_single_connector_modes,
 	.set_property       = slave_connector_set_property,
 };

 static const struct drm_connector_helper_funcs slave_connector_helper_funcs = {
 	.get_modes          = slave_connector_get_modes,
 	.mode_valid         = slave_connector_mode_valid,
 	.best_encoder       = slave_connector_best_encoder,
 };

 static struct drm_connector *slave_connector_create(struct drm_device *dev,
 		struct slave_module *mod, struct drm_encoder *encoder)
 {
 	struct slave_connector *slave_connector;
 	struct drm_connector *connector;
 	int ret;

 	slave_connector = kzalloc(sizeof(*slave_connector), GFP_KERNEL);
 	if (!slave_connector) {
 		dev_err(dev->dev, "allocation failed\n");
 		return NULL;
 	}

 	slave_connector->encoder = encoder;
 	slave_connector->mod = mod;

 	connector = &slave_connector->base;

 	drm_connector_init(dev, connector, &slave_connector_funcs,
 			DRM_MODE_CONNECTOR_HDMIA);
 	drm_connector_helper_add(connector, &slave_connector_helper_funcs);

 	connector->polled = DRM_CONNECTOR_POLL_CONNECT |
 			DRM_CONNECTOR_POLL_DISCONNECT;

 	connector->interlace_allowed = 0;
 	connector->doublescan_allowed = 0;

 	get_slave_funcs(encoder)->create_resources(encoder, connector);

 	ret = drm_mode_connector_attach_encoder(connector, encoder);
 	if (ret)
 		goto fail;

 	drm_sysfs_connector_add(connector);

 	return connector;

 fail:
 	slave_connector_destroy(connector);
 	return NULL;
 }

 /*
  * Module:
  */

 static int slave_modeset_init(struct tilcdc_module *mod, struct drm_device *dev)
 {
 	struct slave_module *slave_mod = to_slave_module(mod);
 	struct tilcdc_drm_private *priv = dev->dev_private;
 	struct drm_encoder *encoder;
 	struct drm_connector *connector;

 	encoder = slave_encoder_create(dev, slave_mod);
 	if (!encoder)
 		return -ENOMEM;

 	connector = slave_connector_create(dev, slave_mod, encoder);
 	if (!connector)
 		return -ENOMEM;

 	priv->encoders[priv->num_encoders++] = encoder;
 	priv->connectors[priv->num_connectors++] = connector;

 	return 0;
 }

 static void slave_destroy(struct tilcdc_module *mod)
 {
 	struct slave_module *slave_mod = to_slave_module(mod);

 	tilcdc_module_cleanup(mod);
 	kfree(slave_mod);
 }

 static const struct tilcdc_module_ops slave_module_ops = {
 		.modeset_init = slave_modeset_init,
 		.destroy = slave_destroy,
 };

 /*
  * Device:
  */

 static struct of_device_id slave_of_match[];

 static int slave_probe(struct platform_device *pdev)
 {
 	struct device_node *node = pdev->dev.of_node;
 	struct device_node *i2c_node;
 	struct slave_module *slave_mod;
 	struct tilcdc_module *mod;
 	struct pinctrl *pinctrl;
 	uint32_t i2c_phandle;
 	struct i2c_adapter *slavei2c;
 	int ret = -EINVAL;

 	/* bail out early if no DT data: */
 	if (!node) {
 		dev_err(&pdev->dev, "device-tree data is missing\n");
 		return -ENXIO;
 	}

 	/* Bail out early if i2c not specified */
 	if (of_property_read_u32(node, "i2c", &i2c_phandle)) {
 		dev_err(&pdev->dev, "could not get i2c bus phandle\n");
 		return ret;
 	}

 	i2c_node = of_find_node_by_phandle(i2c_phandle);
 	if (!i2c_node) {
 		dev_err(&pdev->dev, "could not get i2c bus node\n");
 		return ret;
 	}

 	/* but defer the probe if it can't be initialized it might come later */
 	slavei2c = of_find_i2c_adapter_by_node(i2c_node);
 	of_node_put(i2c_node);

 	if (!slavei2c) {
 		ret = -EPROBE_DEFER;
 		tilcdc_slave_probedefer(true);
 		dev_err(&pdev->dev, "could not get i2c\n");
 		return ret;
 	}

 	slave_mod = kzalloc(sizeof(*slave_mod), GFP_KERNEL);
 	if (!slave_mod)
 		return -ENOMEM;

 	mod = &slave_mod->base;

 	mod->preferred_bpp = slave_info.bpp;

 	slave_mod->i2c = slavei2c;

 	tilcdc_module_init(mod, "slave", &slave_module_ops);

 	pinctrl = devm_pinctrl_get_select_default(&pdev->dev);
 	if (IS_ERR(pinctrl))
 		dev_warn(&pdev->dev, "pins are not configured\n");

 	tilcdc_slave_probedefer(false);

 	return 0;
 }

 static int slave_remove(struct platform_device *pdev)
 {
 	return 0;
 }

 static struct of_device_id slave_of_match[] = {
 		{ .compatible = "ti,tilcdc,slave", },
 		{ },
 };

 struct platform_driver slave_driver = {
 	.probe = slave_probe,
 	.remove = slave_remove,
 	.driver = {
 		.owner = THIS_MODULE,
 		.name = "slave",
 		.of_match_table = slave_of_match,
 	},
 };

 int __init tilcdc_slave_init(void)
 {
 	return platform_driver_register(&slave_driver);
 }

 void __exit tilcdc_slave_fini(void)
 {
 	platform_driver_unregister(&slave_driver);
 }
	/*
	* Copyright (C) 2012 Texas Instruments
	* Author: Rob Clark <robdclark@gmail.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.
	*
	* You should have received a copy of the GNU General Public License along with
	* this program. If not, see <http://www.gnu.org/licenses/>.
	*/

	#include <linux/i2c.h>
	#include <linux/pinctrl/pinmux.h>
	#include <linux/pinctrl/consumer.h>
	#include <drm/drm_encoder_slave.h>

	#include "tilcdc_drv.h"

	struct slave_module {
	struct tilcdc_module base;
	struct i2c_adapter *i2c;
	};
	#define to_slave_module(x) container_of(x, struct slave_module, base)

	static const struct tilcdc_panel_info slave_info = {
	.bpp = 16,
	.ac_bias = 255,
	.ac_bias_intrpt = 0,
	.dma_burst_sz = 16,
	.fdd = 0x80,
	.tft_alt_mode = 0,
	.sync_edge = 0,
	.sync_ctrl = 1,
	.raster_order = 0,
	};


	/*
	* Encoder:
	*/

	struct slave_encoder {
	struct drm_encoder_slave base;
	struct slave_module *mod;
	};
	#define to_slave_encoder(x) container_of(to_encoder_slave(x), struct slave_encoder, base)

	static inline struct drm_encoder_slave_funcs *
	get_slave_funcs(struct drm_encoder *enc)
	{
	return to_encoder_slave(enc)->slave_funcs;
	}

	static void slave_encoder_destroy(struct drm_encoder *encoder)
	{
	struct slave_encoder *slave_encoder = to_slave_encoder(encoder);
	if (get_slave_funcs(encoder))
	get_slave_funcs(encoder)->destroy(encoder);
	drm_encoder_cleanup(encoder);
	kfree(slave_encoder);
	}

	static void slave_encoder_prepare(struct drm_encoder *encoder)
	{
	drm_i2c_encoder_prepare(encoder);
	tilcdc_crtc_set_panel_info(encoder->crtc, &slave_info);
	}

	static bool slave_encoder_fixup(struct drm_encoder *encoder,
	const struct drm_display_mode *mode,
	struct drm_display_mode *adjusted_mode)
	{
	/*
	* tilcdc does not generate VESA-complient sync but aligns
	* VS on the second edge of HS instead of first edge.
	* We use adjusted_mode, to fixup sync by aligning both rising
	* edges and add HSKEW offset to let the slave encoder fix it up.
	*/
	adjusted_mode->hskew = mode->hsync_end - mode->hsync_start;
	adjusted_mode->flags \|= DRM_MODE_FLAG_HSKEW;

	if (mode->flags & DRM_MODE_FLAG_NHSYNC) {
	adjusted_mode->flags \|= DRM_MODE_FLAG_PHSYNC;
	adjusted_mode->flags &= ~DRM_MODE_FLAG_NHSYNC;
	} else {
	adjusted_mode->flags \|= DRM_MODE_FLAG_NHSYNC;
	adjusted_mode->flags &= ~DRM_MODE_FLAG_PHSYNC;
	}

	return drm_i2c_encoder_mode_fixup(encoder, mode, adjusted_mode);
	}


	static const struct drm_encoder_funcs slave_encoder_funcs = {
	.destroy = slave_encoder_destroy,
	};

	static const struct drm_encoder_helper_funcs slave_encoder_helper_funcs = {
	.dpms = drm_i2c_encoder_dpms,
	.mode_fixup = slave_encoder_fixup,
	.prepare = slave_encoder_prepare,
	.commit = drm_i2c_encoder_commit,
	.mode_set = drm_i2c_encoder_mode_set,
	.save = drm_i2c_encoder_save,
	.restore = drm_i2c_encoder_restore,
	};

	static const struct i2c_board_info info = {
	I2C_BOARD_INFO("tda998x", 0x70)
	};

	static struct drm_encoder slave_encoder_create(struct drm_device dev,
	struct slave_module *mod)
	{
	struct slave_encoder *slave_encoder;
	struct drm_encoder *encoder;
	int ret;

	slave_encoder = kzalloc(sizeof(*slave_encoder), GFP_KERNEL);
	if (!slave_encoder) {
	dev_err(dev->dev, "allocation failed\n");
	return NULL;
	}

	slave_encoder->mod = mod;

	encoder = &slave_encoder->base.base;
	encoder->possible_crtcs = 1;

	ret = drm_encoder_init(dev, encoder, &slave_encoder_funcs,
	DRM_MODE_ENCODER_TMDS);
	if (ret)
	goto fail;

	drm_encoder_helper_add(encoder, &slave_encoder_helper_funcs);

	ret = drm_i2c_encoder_init(dev, to_encoder_slave(encoder), mod->i2c, &info);
	if (ret)
	goto fail;

	return encoder;

	fail:
	slave_encoder_destroy(encoder);
	return NULL;
	}

	/*
	* Connector:
	*/

	struct slave_connector {
	struct drm_connector base;

	struct drm_encoder encoder; / our connected encoder */
	struct slave_module *mod;
	};
	#define to_slave_connector(x) container_of(x, struct slave_connector, base)

	static void slave_connector_destroy(struct drm_connector *connector)
	{
	struct slave_connector *slave_connector = to_slave_connector(connector);
	drm_connector_cleanup(connector);
	kfree(slave_connector);
	}

	static enum drm_connector_status slave_connector_detect(
	struct drm_connector *connector,
	bool force)
	{
	struct drm_encoder *encoder = to_slave_connector(connector)->encoder;
	return get_slave_funcs(encoder)->detect(encoder, connector);
	}

	static int slave_connector_get_modes(struct drm_connector *connector)
	{
	struct drm_encoder *encoder = to_slave_connector(connector)->encoder;
	return get_slave_funcs(encoder)->get_modes(encoder, connector);
	}

	static int slave_connector_mode_valid(struct drm_connector *connector,
	struct drm_display_mode *mode)
	{
	struct drm_encoder *encoder = to_slave_connector(connector)->encoder;
	struct tilcdc_drm_private *priv = connector->dev->dev_private;
	int ret;

	ret = tilcdc_crtc_mode_valid(priv->crtc, mode);
	if (ret != MODE_OK)
	return ret;

	return get_slave_funcs(encoder)->mode_valid(encoder, mode);
	}

	static struct drm_encoder *slave_connector_best_encoder(
	struct drm_connector *connector)
	{
	struct slave_connector *slave_connector = to_slave_connector(connector);
	return slave_connector->encoder;
	}

	static int slave_connector_set_property(struct drm_connector *connector,
	struct drm_property *property, uint64_t value)
	{
	struct drm_encoder *encoder = to_slave_connector(connector)->encoder;
	return get_slave_funcs(encoder)->set_property(encoder,
	connector, property, value);
	}

	static const struct drm_connector_funcs slave_connector_funcs = {
	.destroy = slave_connector_destroy,
	.dpms = drm_helper_connector_dpms,
	.detect = slave_connector_detect,
	.fill_modes = drm_helper_probe_single_connector_modes,
	.set_property = slave_connector_set_property,
	};

	static const struct drm_connector_helper_funcs slave_connector_helper_funcs = {
	.get_modes = slave_connector_get_modes,
	.mode_valid = slave_connector_mode_valid,
	.best_encoder = slave_connector_best_encoder,
	};

	static struct drm_connector slave_connector_create(struct drm_device dev,
	struct slave_module mod, struct drm_encoder encoder)
	{
	struct slave_connector *slave_connector;
	struct drm_connector *connector;
	int ret;

	slave_connector = kzalloc(sizeof(*slave_connector), GFP_KERNEL);
	if (!slave_connector) {
	dev_err(dev->dev, "allocation failed\n");
	return NULL;
	}

	slave_connector->encoder = encoder;
	slave_connector->mod = mod;

	connector = &slave_connector->base;

	drm_connector_init(dev, connector, &slave_connector_funcs,
	DRM_MODE_CONNECTOR_HDMIA);
	drm_connector_helper_add(connector, &slave_connector_helper_funcs);

	connector->polled = DRM_CONNECTOR_POLL_CONNECT \|
	DRM_CONNECTOR_POLL_DISCONNECT;

	connector->interlace_allowed = 0;
	connector->doublescan_allowed = 0;

	get_slave_funcs(encoder)->create_resources(encoder, connector);

	ret = drm_mode_connector_attach_encoder(connector, encoder);
	if (ret)
	goto fail;

	drm_sysfs_connector_add(connector);

	return connector;

	fail:
	slave_connector_destroy(connector);
	return NULL;
	}

	/*
	* Module:
	*/

	static int slave_modeset_init(struct tilcdc_module mod, struct drm_device dev)
	{
	struct slave_module *slave_mod = to_slave_module(mod);
	struct tilcdc_drm_private *priv = dev->dev_private;
	struct drm_encoder *encoder;
	struct drm_connector *connector;

	encoder = slave_encoder_create(dev, slave_mod);
	if (!encoder)
	return -ENOMEM;

	connector = slave_connector_create(dev, slave_mod, encoder);
	if (!connector)
	return -ENOMEM;

	priv->encoders[priv->num_encoders++] = encoder;
	priv->connectors[priv->num_connectors++] = connector;

	return 0;
	}

	static void slave_destroy(struct tilcdc_module *mod)
	{
	struct slave_module *slave_mod = to_slave_module(mod);

	tilcdc_module_cleanup(mod);
	kfree(slave_mod);
	}

	static const struct tilcdc_module_ops slave_module_ops = {
	.modeset_init = slave_modeset_init,
	.destroy = slave_destroy,
	};

	/*
	* Device:
	*/

	static struct of_device_id slave_of_match[];

	static int slave_probe(struct platform_device *pdev)
	{
	struct device_node *node = pdev->dev.of_node;
	struct device_node *i2c_node;
	struct slave_module *slave_mod;
	struct tilcdc_module *mod;
	struct pinctrl *pinctrl;
	uint32_t i2c_phandle;
	struct i2c_adapter *slavei2c;
	int ret = -EINVAL;

	/* bail out early if no DT data: */
	if (!node) {
	dev_err(&pdev->dev, "device-tree data is missing\n");
	return -ENXIO;
	}

	/* Bail out early if i2c not specified */
	if (of_property_read_u32(node, "i2c", &i2c_phandle)) {
	dev_err(&pdev->dev, "could not get i2c bus phandle\n");
	return ret;
	}

	i2c_node = of_find_node_by_phandle(i2c_phandle);
	if (!i2c_node) {
	dev_err(&pdev->dev, "could not get i2c bus node\n");
	return ret;
	}

	/* but defer the probe if it can't be initialized it might come later */
	slavei2c = of_find_i2c_adapter_by_node(i2c_node);
	of_node_put(i2c_node);

	if (!slavei2c) {
	ret = -EPROBE_DEFER;
	tilcdc_slave_probedefer(true);
	dev_err(&pdev->dev, "could not get i2c\n");
	return ret;
	}

	slave_mod = kzalloc(sizeof(*slave_mod), GFP_KERNEL);
	if (!slave_mod)
	return -ENOMEM;

	mod = &slave_mod->base;

	mod->preferred_bpp = slave_info.bpp;

	slave_mod->i2c = slavei2c;

	tilcdc_module_init(mod, "slave", &slave_module_ops);

	pinctrl = devm_pinctrl_get_select_default(&pdev->dev);
	if (IS_ERR(pinctrl))
	dev_warn(&pdev->dev, "pins are not configured\n");

	tilcdc_slave_probedefer(false);

	return 0;
	}

	static int slave_remove(struct platform_device *pdev)
	{
	return 0;
	}

	static struct of_device_id slave_of_match[] = {
	{ .compatible = "ti,tilcdc,slave", },
	{ },
	};

	struct platform_driver slave_driver = {
	.probe = slave_probe,
	.remove = slave_remove,
	.driver = {
	.owner = THIS_MODULE,
	.name = "slave",
	.of_match_table = slave_of_match,
	},
	};

	int __init tilcdc_slave_init(void)
	{
	return platform_driver_register(&slave_driver);
	}

	void __exit tilcdc_slave_fini(void)
	{
	platform_driver_unregister(&slave_driver);
	}