drivers/gpu/drm/i2c/sil164_drv.c - arm/linux-arm64-legacy - Git at Google

 /*
  * Copyright (C) 2010 Francisco Jerez.
  * All Rights Reserved.
  *
  * Permission is hereby granted, free of charge, to any person obtaining
  * a copy of this software and associated documentation files (the
  * "Software"), to deal in the Software without restriction, including
  * without limitation the rights to use, copy, modify, merge, publish,
  * distribute, sublicense, and/or sell copies of the Software, and to
  * permit persons to whom the Software is furnished to do so, subject to
  * the following conditions:
  *
  * The above copyright notice and this permission notice (including the
  * next paragraph) shall be included in all copies or substantial
  * portions of the Software.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
  * IN NO EVENT SHALL THE COPYRIGHT OWNER(S) AND/OR ITS SUPPLIERS BE
  * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  *
  */

 #include "drmP.h"
 #include "drm_crtc_helper.h"
 #include "drm_encoder_slave.h"
 #include "i2c/sil164.h"

 struct sil164_priv {
 	struct sil164_encoder_params config;
 	struct i2c_client *duallink_slave;

 	uint8_t saved_state[0x10];
 	uint8_t saved_slave_state[0x10];
 };

 #define to_sil164_priv(x) \
 	((struct sil164_priv *)to_encoder_slave(x)->slave_priv)

 #define sil164_dbg(client, format, ...) do {				\
 		if (drm_debug & DRM_UT_KMS)				\
 			dev_printk(KERN_DEBUG, &client->dev,		\
 				   "%s: " format, __func__, ## __VA_ARGS__); \
 	} while (0)
 #define sil164_info(client, format, ...)		\
 	dev_info(&client->dev, format, __VA_ARGS__)
 #define sil164_err(client, format, ...)			\
 	dev_err(&client->dev, format, __VA_ARGS__)

 #define SIL164_I2C_ADDR_MASTER			0x38
 #define SIL164_I2C_ADDR_SLAVE			0x39

 /* HW register definitions */

 #define SIL164_VENDOR_LO			0x0
 #define SIL164_VENDOR_HI			0x1
 #define SIL164_DEVICE_LO			0x2
 #define SIL164_DEVICE_HI			0x3
 #define SIL164_REVISION				0x4
 #define SIL164_FREQ_MIN				0x6
 #define SIL164_FREQ_MAX				0x7
 #define SIL164_CONTROL0				0x8
 #  define SIL164_CONTROL0_POWER_ON		0x01
 #  define SIL164_CONTROL0_EDGE_RISING		0x02
 #  define SIL164_CONTROL0_INPUT_24BIT		0x04
 #  define SIL164_CONTROL0_DUAL_EDGE		0x08
 #  define SIL164_CONTROL0_HSYNC_ON		0x10
 #  define SIL164_CONTROL0_VSYNC_ON		0x20
 #define SIL164_DETECT				0x9
 #  define SIL164_DETECT_INTR_STAT		0x01
 #  define SIL164_DETECT_HOTPLUG_STAT		0x02
 #  define SIL164_DETECT_RECEIVER_STAT		0x04
 #  define SIL164_DETECT_INTR_MODE_RECEIVER	0x00
 #  define SIL164_DETECT_INTR_MODE_HOTPLUG	0x08
 #  define SIL164_DETECT_OUT_MODE_HIGH		0x00
 #  define SIL164_DETECT_OUT_MODE_INTR		0x10
 #  define SIL164_DETECT_OUT_MODE_RECEIVER	0x20
 #  define SIL164_DETECT_OUT_MODE_HOTPLUG	0x30
 #  define SIL164_DETECT_VSWING_STAT		0x80
 #define SIL164_CONTROL1				0xa
 #  define SIL164_CONTROL1_DESKEW_ENABLE		0x10
 #  define SIL164_CONTROL1_DESKEW_INCR_SHIFT	5
 #define SIL164_GPIO				0xb
 #define SIL164_CONTROL2				0xc
 #  define SIL164_CONTROL2_FILTER_ENABLE		0x01
 #  define SIL164_CONTROL2_FILTER_SETTING_SHIFT	1
 #  define SIL164_CONTROL2_DUALLINK_MASTER	0x40
 #  define SIL164_CONTROL2_SYNC_CONT		0x80
 #define SIL164_DUALLINK				0xd
 #  define SIL164_DUALLINK_ENABLE		0x10
 #  define SIL164_DUALLINK_SKEW_SHIFT		5
 #define SIL164_PLLZONE				0xe
 #  define SIL164_PLLZONE_STAT			0x08
 #  define SIL164_PLLZONE_FORCE_ON		0x10
 #  define SIL164_PLLZONE_FORCE_HIGH		0x20

 /* HW access functions */

 static void
 sil164_write(struct i2c_client *client, uint8_t addr, uint8_t val)
 {
 	uint8_t buf[] = {addr, val};
 	int ret;

 	ret = i2c_master_send(client, buf, ARRAY_SIZE(buf));
 	if (ret < 0)
 		sil164_err(client, "Error %d writing to subaddress 0x%x\n",
 			   ret, addr);
 }

 static uint8_t
 sil164_read(struct i2c_client *client, uint8_t addr)
 {
 	uint8_t val;
 	int ret;

 	ret = i2c_master_send(client, &addr, sizeof(addr));
 	if (ret < 0)
 		goto fail;

 	ret = i2c_master_recv(client, &val, sizeof(val));
 	if (ret < 0)
 		goto fail;

 	return val;

 fail:
 	sil164_err(client, "Error %d reading from subaddress 0x%x\n",
 		   ret, addr);
 	return 0;
 }

 static void
 sil164_save_state(struct i2c_client *client, uint8_t *state)
 {
 	int i;

 	for (i = 0x8; i <= 0xe; i++)
 		state[i] = sil164_read(client, i);
 }

 static void
 sil164_restore_state(struct i2c_client *client, uint8_t *state)
 {
 	int i;

 	for (i = 0x8; i <= 0xe; i++)
 		sil164_write(client, i, state[i]);
 }

 static void
 sil164_set_power_state(struct i2c_client *client, bool on)
 {
 	uint8_t control0 = sil164_read(client, SIL164_CONTROL0);

 	if (on)
 		control0 |= SIL164_CONTROL0_POWER_ON;
 	else
 		control0 &= ~SIL164_CONTROL0_POWER_ON;

 	sil164_write(client, SIL164_CONTROL0, control0);
 }

 static void
 sil164_init_state(struct i2c_client *client,
 		  struct sil164_encoder_params *config,
 		  bool duallink)
 {
 	sil164_write(client, SIL164_CONTROL0,
 		     SIL164_CONTROL0_HSYNC_ON |
 		     SIL164_CONTROL0_VSYNC_ON |
 		     (config->input_edge ? SIL164_CONTROL0_EDGE_RISING : 0) |
 		     (config->input_width ? SIL164_CONTROL0_INPUT_24BIT : 0) |
 		     (config->input_dual ? SIL164_CONTROL0_DUAL_EDGE : 0));

 	sil164_write(client, SIL164_DETECT,
 		     SIL164_DETECT_INTR_STAT |
 		     SIL164_DETECT_OUT_MODE_RECEIVER);

 	sil164_write(client, SIL164_CONTROL1,
 		     (config->input_skew ? SIL164_CONTROL1_DESKEW_ENABLE : 0) |
 		     (((config->input_skew + 4) & 0x7)
 		      << SIL164_CONTROL1_DESKEW_INCR_SHIFT));

 	sil164_write(client, SIL164_CONTROL2,
 		     SIL164_CONTROL2_SYNC_CONT |
 		     (config->pll_filter ? 0 : SIL164_CONTROL2_FILTER_ENABLE) |
 		     (4 << SIL164_CONTROL2_FILTER_SETTING_SHIFT));

 	sil164_write(client, SIL164_PLLZONE, 0);

 	if (duallink)
 		sil164_write(client, SIL164_DUALLINK,
 			     SIL164_DUALLINK_ENABLE |
 			     (((config->duallink_skew + 4) & 0x7)
 			      << SIL164_DUALLINK_SKEW_SHIFT));
 	else
 		sil164_write(client, SIL164_DUALLINK, 0);
 }

 /* DRM encoder functions */

 static void
 sil164_encoder_set_config(struct drm_encoder *encoder, void *params)
 {
 	struct sil164_priv *priv = to_sil164_priv(encoder);

 	priv->config = *(struct sil164_encoder_params *)params;
 }

 static void
 sil164_encoder_dpms(struct drm_encoder *encoder, int mode)
 {
 	struct sil164_priv *priv = to_sil164_priv(encoder);
 	bool on = (mode == DRM_MODE_DPMS_ON);
 	bool duallink = (on && encoder->crtc->mode.clock > 165000);

 	sil164_set_power_state(drm_i2c_encoder_get_client(encoder), on);

 	if (priv->duallink_slave)
 		sil164_set_power_state(priv->duallink_slave, duallink);
 }

 static void
 sil164_encoder_save(struct drm_encoder *encoder)
 {
 	struct sil164_priv *priv = to_sil164_priv(encoder);

 	sil164_save_state(drm_i2c_encoder_get_client(encoder),
 			  priv->saved_state);

 	if (priv->duallink_slave)
 		sil164_save_state(priv->duallink_slave,
 				  priv->saved_slave_state);
 }

 static void
 sil164_encoder_restore(struct drm_encoder *encoder)
 {
 	struct sil164_priv *priv = to_sil164_priv(encoder);

 	sil164_restore_state(drm_i2c_encoder_get_client(encoder),
 			     priv->saved_state);

 	if (priv->duallink_slave)
 		sil164_restore_state(priv->duallink_slave,
 				     priv->saved_slave_state);
 }

 static bool
 sil164_encoder_mode_fixup(struct drm_encoder *encoder,
 			  struct drm_display_mode *mode,
 			  struct drm_display_mode *adjusted_mode)
 {
 	return true;
 }

 static int
 sil164_encoder_mode_valid(struct drm_encoder *encoder,
 			  struct drm_display_mode *mode)
 {
 	struct sil164_priv *priv = to_sil164_priv(encoder);

 	if (mode->clock < 32000)
 		return MODE_CLOCK_LOW;

 	if (mode->clock > 330000 ||
 	    (mode->clock > 165000 && !priv->duallink_slave))
 		return MODE_CLOCK_HIGH;

 	return MODE_OK;
 }

 static void
 sil164_encoder_mode_set(struct drm_encoder *encoder,
 			struct drm_display_mode *mode,
 			struct drm_display_mode *adjusted_mode)
 {
 	struct sil164_priv *priv = to_sil164_priv(encoder);
 	bool duallink = adjusted_mode->clock > 165000;

 	sil164_init_state(drm_i2c_encoder_get_client(encoder),
 			  &priv->config, duallink);

 	if (priv->duallink_slave)
 		sil164_init_state(priv->duallink_slave,
 				  &priv->config, duallink);

 	sil164_encoder_dpms(encoder, DRM_MODE_DPMS_ON);
 }

 static enum drm_connector_status
 sil164_encoder_detect(struct drm_encoder *encoder,
 		      struct drm_connector *connector)
 {
 	struct i2c_client *client = drm_i2c_encoder_get_client(encoder);

 	if (sil164_read(client, SIL164_DETECT) & SIL164_DETECT_HOTPLUG_STAT)
 		return connector_status_connected;
 	else
 		return connector_status_disconnected;
 }

 static int
 sil164_encoder_get_modes(struct drm_encoder *encoder,
 			 struct drm_connector *connector)
 {
 	return 0;
 }

 static int
 sil164_encoder_create_resources(struct drm_encoder *encoder,
 				struct drm_connector *connector)
 {
 	return 0;
 }

 static int
 sil164_encoder_set_property(struct drm_encoder *encoder,
 			    struct drm_connector *connector,
 			    struct drm_property *property,
 			    uint64_t val)
 {
 	return 0;
 }

 static void
 sil164_encoder_destroy(struct drm_encoder *encoder)
 {
 	struct sil164_priv *priv = to_sil164_priv(encoder);

 	if (priv->duallink_slave)
 		i2c_unregister_device(priv->duallink_slave);

 	kfree(priv);
 	drm_i2c_encoder_destroy(encoder);
 }

 static struct drm_encoder_slave_funcs sil164_encoder_funcs = {
 	.set_config = sil164_encoder_set_config,
 	.destroy = sil164_encoder_destroy,
 	.dpms = sil164_encoder_dpms,
 	.save = sil164_encoder_save,
 	.restore = sil164_encoder_restore,
 	.mode_fixup = sil164_encoder_mode_fixup,
 	.mode_valid = sil164_encoder_mode_valid,
 	.mode_set = sil164_encoder_mode_set,
 	.detect = sil164_encoder_detect,
 	.get_modes = sil164_encoder_get_modes,
 	.create_resources = sil164_encoder_create_resources,
 	.set_property = sil164_encoder_set_property,
 };

 /* I2C driver functions */

 static int
 sil164_probe(struct i2c_client *client, const struct i2c_device_id *id)
 {
 	int vendor = sil164_read(client, SIL164_VENDOR_HI) << 8 |
 		sil164_read(client, SIL164_VENDOR_LO);
 	int device = sil164_read(client, SIL164_DEVICE_HI) << 8 |
 		sil164_read(client, SIL164_DEVICE_LO);
 	int rev = sil164_read(client, SIL164_REVISION);

 	if (vendor != 0x1 || device != 0x6) {
 		sil164_dbg(client, "Unknown device %x:%x.%x\n",
 			   vendor, device, rev);
 		return -ENODEV;
 	}

 	sil164_info(client, "Detected device %x:%x.%x\n",
 		    vendor, device, rev);

 	return 0;
 }

 static int
 sil164_remove(struct i2c_client *client)
 {
 	return 0;
 }

 static struct i2c_client *
 sil164_detect_slave(struct i2c_client *client)
 {
 	struct i2c_adapter *adap = client->adapter;
 	struct i2c_msg msg = {
 		.addr = SIL164_I2C_ADDR_SLAVE,
 		.len = 0,
 	};
 	const struct i2c_board_info info = {
 		I2C_BOARD_INFO("sil164", SIL164_I2C_ADDR_SLAVE)
 	};

 	if (i2c_transfer(adap, &msg, 1) != 1) {
 		sil164_dbg(adap, "No dual-link slave found.");
 		return NULL;
 	}

 	return i2c_new_device(adap, &info);
 }

 static int
 sil164_encoder_init(struct i2c_client *client,
 		    struct drm_device *dev,
 		    struct drm_encoder_slave *encoder)
 {
 	struct sil164_priv *priv;

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

 	encoder->slave_priv = priv;
 	encoder->slave_funcs = &sil164_encoder_funcs;

 	priv->duallink_slave = sil164_detect_slave(client);

 	return 0;
 }

 static struct i2c_device_id sil164_ids[] = {
 	{ "sil164", 0 },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, sil164_ids);

 static struct drm_i2c_encoder_driver sil164_driver = {
 	.i2c_driver = {
 		.probe = sil164_probe,
 		.remove = sil164_remove,
 		.driver = {
 			.name = "sil164",
 		},
 		.id_table = sil164_ids,
 	},
 	.encoder_init = sil164_encoder_init,
 };

 /* Module initialization */

 static int __init
 sil164_init(void)
 {
 	return drm_i2c_encoder_register(THIS_MODULE, &sil164_driver);
 }

 static void __exit
 sil164_exit(void)
 {
 	drm_i2c_encoder_unregister(&sil164_driver);
 }

 MODULE_AUTHOR("Francisco Jerez <currojerez@riseup.net>");
 MODULE_DESCRIPTION("Silicon Image sil164 TMDS transmitter driver");
 MODULE_LICENSE("GPL and additional rights");

 module_init(sil164_init);
 module_exit(sil164_exit);
	/*
	* Copyright (C) 2010 Francisco Jerez.
	* All Rights Reserved.
	*
	* Permission is hereby granted, free of charge, to any person obtaining
	* a copy of this software and associated documentation files (the
	* "Software"), to deal in the Software without restriction, including
	* without limitation the rights to use, copy, modify, merge, publish,
	* distribute, sublicense, and/or sell copies of the Software, and to
	* permit persons to whom the Software is furnished to do so, subject to
	* the following conditions:
	*
	* The above copyright notice and this permission notice (including the
	* next paragraph) shall be included in all copies or substantial
	* portions of the Software.
	*
	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
	* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
	* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
	* IN NO EVENT SHALL THE COPYRIGHT OWNER(S) AND/OR ITS SUPPLIERS BE
	* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
	* OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
	* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
	*
	*/

	#include "drmP.h"
	#include "drm_crtc_helper.h"
	#include "drm_encoder_slave.h"
	#include "i2c/sil164.h"

	struct sil164_priv {
	struct sil164_encoder_params config;
	struct i2c_client *duallink_slave;

	uint8_t saved_state[0x10];
	uint8_t saved_slave_state[0x10];
	};

	#define to_sil164_priv(x) \
	((struct sil164_priv *)to_encoder_slave(x)->slave_priv)

	#define sil164_dbg(client, format, ...) do { \
	if (drm_debug & DRM_UT_KMS) \
	dev_printk(KERN_DEBUG, &client->dev, \
	"%s: " format, __func__, ## __VA_ARGS__); \
	} while (0)
	#define sil164_info(client, format, ...) \
	dev_info(&client->dev, format, __VA_ARGS__)
	#define sil164_err(client, format, ...) \
	dev_err(&client->dev, format, __VA_ARGS__)

	#define SIL164_I2C_ADDR_MASTER 0x38
	#define SIL164_I2C_ADDR_SLAVE 0x39

	/* HW register definitions */

	#define SIL164_VENDOR_LO 0x0
	#define SIL164_VENDOR_HI 0x1
	#define SIL164_DEVICE_LO 0x2
	#define SIL164_DEVICE_HI 0x3
	#define SIL164_REVISION 0x4
	#define SIL164_FREQ_MIN 0x6
	#define SIL164_FREQ_MAX 0x7
	#define SIL164_CONTROL0 0x8
	# define SIL164_CONTROL0_POWER_ON 0x01
	# define SIL164_CONTROL0_EDGE_RISING 0x02
	# define SIL164_CONTROL0_INPUT_24BIT 0x04
	# define SIL164_CONTROL0_DUAL_EDGE 0x08
	# define SIL164_CONTROL0_HSYNC_ON 0x10
	# define SIL164_CONTROL0_VSYNC_ON 0x20
	#define SIL164_DETECT 0x9
	# define SIL164_DETECT_INTR_STAT 0x01
	# define SIL164_DETECT_HOTPLUG_STAT 0x02
	# define SIL164_DETECT_RECEIVER_STAT 0x04
	# define SIL164_DETECT_INTR_MODE_RECEIVER 0x00
	# define SIL164_DETECT_INTR_MODE_HOTPLUG 0x08
	# define SIL164_DETECT_OUT_MODE_HIGH 0x00
	# define SIL164_DETECT_OUT_MODE_INTR 0x10
	# define SIL164_DETECT_OUT_MODE_RECEIVER 0x20
	# define SIL164_DETECT_OUT_MODE_HOTPLUG 0x30
	# define SIL164_DETECT_VSWING_STAT 0x80
	#define SIL164_CONTROL1 0xa
	# define SIL164_CONTROL1_DESKEW_ENABLE 0x10
	# define SIL164_CONTROL1_DESKEW_INCR_SHIFT 5
	#define SIL164_GPIO 0xb
	#define SIL164_CONTROL2 0xc
	# define SIL164_CONTROL2_FILTER_ENABLE 0x01
	# define SIL164_CONTROL2_FILTER_SETTING_SHIFT 1
	# define SIL164_CONTROL2_DUALLINK_MASTER 0x40
	# define SIL164_CONTROL2_SYNC_CONT 0x80
	#define SIL164_DUALLINK 0xd
	# define SIL164_DUALLINK_ENABLE 0x10
	# define SIL164_DUALLINK_SKEW_SHIFT 5
	#define SIL164_PLLZONE 0xe
	# define SIL164_PLLZONE_STAT 0x08
	# define SIL164_PLLZONE_FORCE_ON 0x10
	# define SIL164_PLLZONE_FORCE_HIGH 0x20

	/* HW access functions */

	static void
	sil164_write(struct i2c_client *client, uint8_t addr, uint8_t val)
	{
	uint8_t buf[] = {addr, val};
	int ret;

	ret = i2c_master_send(client, buf, ARRAY_SIZE(buf));
	if (ret < 0)
	sil164_err(client, "Error %d writing to subaddress 0x%x\n",
	ret, addr);
	}

	static uint8_t
	sil164_read(struct i2c_client *client, uint8_t addr)
	{
	uint8_t val;
	int ret;

	ret = i2c_master_send(client, &addr, sizeof(addr));
	if (ret < 0)
	goto fail;

	ret = i2c_master_recv(client, &val, sizeof(val));
	if (ret < 0)
	goto fail;

	return val;

	fail:
	sil164_err(client, "Error %d reading from subaddress 0x%x\n",
	ret, addr);
	return 0;
	}

	static void
	sil164_save_state(struct i2c_client client, uint8_t state)
	{
	int i;

	for (i = 0x8; i <= 0xe; i++)
	state[i] = sil164_read(client, i);
	}

	static void
	sil164_restore_state(struct i2c_client client, uint8_t state)
	{
	int i;

	for (i = 0x8; i <= 0xe; i++)
	sil164_write(client, i, state[i]);
	}

	static void
	sil164_set_power_state(struct i2c_client *client, bool on)
	{
	uint8_t control0 = sil164_read(client, SIL164_CONTROL0);

	if (on)
	control0 \|= SIL164_CONTROL0_POWER_ON;
	else
	control0 &= ~SIL164_CONTROL0_POWER_ON;

	sil164_write(client, SIL164_CONTROL0, control0);
	}

	static void
	sil164_init_state(struct i2c_client *client,
	struct sil164_encoder_params *config,
	bool duallink)
	{
	sil164_write(client, SIL164_CONTROL0,
	SIL164_CONTROL0_HSYNC_ON \|
	SIL164_CONTROL0_VSYNC_ON \|
	(config->input_edge ? SIL164_CONTROL0_EDGE_RISING : 0) \|
	(config->input_width ? SIL164_CONTROL0_INPUT_24BIT : 0) \|
	(config->input_dual ? SIL164_CONTROL0_DUAL_EDGE : 0));

	sil164_write(client, SIL164_DETECT,
	SIL164_DETECT_INTR_STAT \|
	SIL164_DETECT_OUT_MODE_RECEIVER);

	sil164_write(client, SIL164_CONTROL1,
	(config->input_skew ? SIL164_CONTROL1_DESKEW_ENABLE : 0) \|
	(((config->input_skew + 4) & 0x7)
	<< SIL164_CONTROL1_DESKEW_INCR_SHIFT));

	sil164_write(client, SIL164_CONTROL2,
	SIL164_CONTROL2_SYNC_CONT \|
	(config->pll_filter ? 0 : SIL164_CONTROL2_FILTER_ENABLE) \|
	(4 << SIL164_CONTROL2_FILTER_SETTING_SHIFT));

	sil164_write(client, SIL164_PLLZONE, 0);

	if (duallink)
	sil164_write(client, SIL164_DUALLINK,
	SIL164_DUALLINK_ENABLE \|
	(((config->duallink_skew + 4) & 0x7)
	<< SIL164_DUALLINK_SKEW_SHIFT));
	else
	sil164_write(client, SIL164_DUALLINK, 0);
	}

	/* DRM encoder functions */

	static void
	sil164_encoder_set_config(struct drm_encoder encoder, void params)
	{
	struct sil164_priv *priv = to_sil164_priv(encoder);

	priv->config = (struct sil164_encoder_params )params;
	}

	static void
	sil164_encoder_dpms(struct drm_encoder *encoder, int mode)
	{
	struct sil164_priv *priv = to_sil164_priv(encoder);
	bool on = (mode == DRM_MODE_DPMS_ON);
	bool duallink = (on && encoder->crtc->mode.clock > 165000);

	sil164_set_power_state(drm_i2c_encoder_get_client(encoder), on);

	if (priv->duallink_slave)
	sil164_set_power_state(priv->duallink_slave, duallink);
	}

	static void
	sil164_encoder_save(struct drm_encoder *encoder)
	{
	struct sil164_priv *priv = to_sil164_priv(encoder);

	sil164_save_state(drm_i2c_encoder_get_client(encoder),
	priv->saved_state);

	if (priv->duallink_slave)
	sil164_save_state(priv->duallink_slave,
	priv->saved_slave_state);
	}

	static void
	sil164_encoder_restore(struct drm_encoder *encoder)
	{
	struct sil164_priv *priv = to_sil164_priv(encoder);

	sil164_restore_state(drm_i2c_encoder_get_client(encoder),
	priv->saved_state);

	if (priv->duallink_slave)
	sil164_restore_state(priv->duallink_slave,
	priv->saved_slave_state);
	}

	static bool
	sil164_encoder_mode_fixup(struct drm_encoder *encoder,
	struct drm_display_mode *mode,
	struct drm_display_mode *adjusted_mode)
	{
	return true;
	}

	static int
	sil164_encoder_mode_valid(struct drm_encoder *encoder,
	struct drm_display_mode *mode)
	{
	struct sil164_priv *priv = to_sil164_priv(encoder);

	if (mode->clock < 32000)
	return MODE_CLOCK_LOW;

	if (mode->clock > 330000 \|\|
	(mode->clock > 165000 && !priv->duallink_slave))
	return MODE_CLOCK_HIGH;

	return MODE_OK;
	}

	static void
	sil164_encoder_mode_set(struct drm_encoder *encoder,
	struct drm_display_mode *mode,
	struct drm_display_mode *adjusted_mode)
	{
	struct sil164_priv *priv = to_sil164_priv(encoder);
	bool duallink = adjusted_mode->clock > 165000;

	sil164_init_state(drm_i2c_encoder_get_client(encoder),
	&priv->config, duallink);

	if (priv->duallink_slave)
	sil164_init_state(priv->duallink_slave,
	&priv->config, duallink);

	sil164_encoder_dpms(encoder, DRM_MODE_DPMS_ON);
	}

	static enum drm_connector_status
	sil164_encoder_detect(struct drm_encoder *encoder,
	struct drm_connector *connector)
	{
	struct i2c_client *client = drm_i2c_encoder_get_client(encoder);

	if (sil164_read(client, SIL164_DETECT) & SIL164_DETECT_HOTPLUG_STAT)
	return connector_status_connected;
	else
	return connector_status_disconnected;
	}

	static int
	sil164_encoder_get_modes(struct drm_encoder *encoder,
	struct drm_connector *connector)
	{
	return 0;
	}

	static int
	sil164_encoder_create_resources(struct drm_encoder *encoder,
	struct drm_connector *connector)
	{
	return 0;
	}

	static int
	sil164_encoder_set_property(struct drm_encoder *encoder,
	struct drm_connector *connector,
	struct drm_property *property,
	uint64_t val)
	{
	return 0;
	}

	static void
	sil164_encoder_destroy(struct drm_encoder *encoder)
	{
	struct sil164_priv *priv = to_sil164_priv(encoder);

	if (priv->duallink_slave)
	i2c_unregister_device(priv->duallink_slave);

	kfree(priv);
	drm_i2c_encoder_destroy(encoder);
	}

	static struct drm_encoder_slave_funcs sil164_encoder_funcs = {
	.set_config = sil164_encoder_set_config,
	.destroy = sil164_encoder_destroy,
	.dpms = sil164_encoder_dpms,
	.save = sil164_encoder_save,
	.restore = sil164_encoder_restore,
	.mode_fixup = sil164_encoder_mode_fixup,
	.mode_valid = sil164_encoder_mode_valid,
	.mode_set = sil164_encoder_mode_set,
	.detect = sil164_encoder_detect,
	.get_modes = sil164_encoder_get_modes,
	.create_resources = sil164_encoder_create_resources,
	.set_property = sil164_encoder_set_property,
	};

	/* I2C driver functions */

	static int
	sil164_probe(struct i2c_client client, const struct i2c_device_id id)
	{
	int vendor = sil164_read(client, SIL164_VENDOR_HI) << 8 \|
	sil164_read(client, SIL164_VENDOR_LO);
	int device = sil164_read(client, SIL164_DEVICE_HI) << 8 \|
	sil164_read(client, SIL164_DEVICE_LO);
	int rev = sil164_read(client, SIL164_REVISION);

	if (vendor != 0x1 \|\| device != 0x6) {
	sil164_dbg(client, "Unknown device %x:%x.%x\n",
	vendor, device, rev);
	return -ENODEV;
	}

	sil164_info(client, "Detected device %x:%x.%x\n",
	vendor, device, rev);

	return 0;
	}

	static int
	sil164_remove(struct i2c_client *client)
	{
	return 0;
	}

	static struct i2c_client *
	sil164_detect_slave(struct i2c_client *client)
	{
	struct i2c_adapter *adap = client->adapter;
	struct i2c_msg msg = {
	.addr = SIL164_I2C_ADDR_SLAVE,
	.len = 0,
	};
	const struct i2c_board_info info = {
	I2C_BOARD_INFO("sil164", SIL164_I2C_ADDR_SLAVE)
	};

	if (i2c_transfer(adap, &msg, 1) != 1) {
	sil164_dbg(adap, "No dual-link slave found.");
	return NULL;
	}

	return i2c_new_device(adap, &info);
	}

	static int
	sil164_encoder_init(struct i2c_client *client,
	struct drm_device *dev,
	struct drm_encoder_slave *encoder)
	{
	struct sil164_priv *priv;

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

	encoder->slave_priv = priv;
	encoder->slave_funcs = &sil164_encoder_funcs;

	priv->duallink_slave = sil164_detect_slave(client);

	return 0;
	}

	static struct i2c_device_id sil164_ids[] = {
	{ "sil164", 0 },
	{ }
	};
	MODULE_DEVICE_TABLE(i2c, sil164_ids);

	static struct drm_i2c_encoder_driver sil164_driver = {
	.i2c_driver = {
	.probe = sil164_probe,
	.remove = sil164_remove,
	.driver = {
	.name = "sil164",
	},
	.id_table = sil164_ids,
	},
	.encoder_init = sil164_encoder_init,
	};

	/* Module initialization */

	static int __init
	sil164_init(void)
	{
	return drm_i2c_encoder_register(THIS_MODULE, &sil164_driver);
	}

	static void __exit
	sil164_exit(void)
	{
	drm_i2c_encoder_unregister(&sil164_driver);
	}

	MODULE_AUTHOR("Francisco Jerez <currojerez@riseup.net>");
	MODULE_DESCRIPTION("Silicon Image sil164 TMDS transmitter driver");
	MODULE_LICENSE("GPL and additional rights");

	module_init(sil164_init);
	module_exit(sil164_exit);