drivers/gpu/drm/msm/hdmi/hdmi_i2c.c - linux - Git at Google

 /*
  * Copyright (C) 2013 Red Hat
  * 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 "hdmi.h"

 struct hdmi_i2c_adapter {
 	struct i2c_adapter base;
 	struct hdmi *hdmi;
 	bool sw_done;
 	wait_queue_head_t ddc_event;
 };
 #define to_hdmi_i2c_adapter(x) container_of(x, struct hdmi_i2c_adapter, base)

 static void init_ddc(struct hdmi_i2c_adapter *hdmi_i2c)
 {
 	struct hdmi *hdmi = hdmi_i2c->hdmi;

 	hdmi_write(hdmi, REG_HDMI_DDC_CTRL,
 			HDMI_DDC_CTRL_SW_STATUS_RESET);
 	hdmi_write(hdmi, REG_HDMI_DDC_CTRL,
 			HDMI_DDC_CTRL_SOFT_RESET);

 	hdmi_write(hdmi, REG_HDMI_DDC_SPEED,
 			HDMI_DDC_SPEED_THRESHOLD(2) |
 			HDMI_DDC_SPEED_PRESCALE(10));

 	hdmi_write(hdmi, REG_HDMI_DDC_SETUP,
 			HDMI_DDC_SETUP_TIMEOUT(0xff));

 	/* enable reference timer for 27us */
 	hdmi_write(hdmi, REG_HDMI_DDC_REF,
 			HDMI_DDC_REF_REFTIMER_ENABLE |
 			HDMI_DDC_REF_REFTIMER(27));
 }

 static int ddc_clear_irq(struct hdmi_i2c_adapter *hdmi_i2c)
 {
 	struct hdmi *hdmi = hdmi_i2c->hdmi;
 	struct drm_device *dev = hdmi->dev;
 	uint32_t retry = 0xffff;
 	uint32_t ddc_int_ctrl;

 	do {
 		--retry;

 		hdmi_write(hdmi, REG_HDMI_DDC_INT_CTRL,
 				HDMI_DDC_INT_CTRL_SW_DONE_ACK |
 				HDMI_DDC_INT_CTRL_SW_DONE_MASK);

 		ddc_int_ctrl = hdmi_read(hdmi, REG_HDMI_DDC_INT_CTRL);

 	} while ((ddc_int_ctrl & HDMI_DDC_INT_CTRL_SW_DONE_INT) && retry);

 	if (!retry) {
 		DRM_DEV_ERROR(dev->dev, "timeout waiting for DDC\n");
 		return -ETIMEDOUT;
 	}

 	hdmi_i2c->sw_done = false;

 	return 0;
 }

 #define MAX_TRANSACTIONS 4

 static bool sw_done(struct hdmi_i2c_adapter *hdmi_i2c)
 {
 	struct hdmi *hdmi = hdmi_i2c->hdmi;

 	if (!hdmi_i2c->sw_done) {
 		uint32_t ddc_int_ctrl;

 		ddc_int_ctrl = hdmi_read(hdmi, REG_HDMI_DDC_INT_CTRL);

 		if ((ddc_int_ctrl & HDMI_DDC_INT_CTRL_SW_DONE_MASK) &&
 				(ddc_int_ctrl & HDMI_DDC_INT_CTRL_SW_DONE_INT)) {
 			hdmi_i2c->sw_done = true;
 			hdmi_write(hdmi, REG_HDMI_DDC_INT_CTRL,
 					HDMI_DDC_INT_CTRL_SW_DONE_ACK);
 		}
 	}

 	return hdmi_i2c->sw_done;
 }

 static int msm_hdmi_i2c_xfer(struct i2c_adapter *i2c,
 		struct i2c_msg *msgs, int num)
 {
 	struct hdmi_i2c_adapter *hdmi_i2c = to_hdmi_i2c_adapter(i2c);
 	struct hdmi *hdmi = hdmi_i2c->hdmi;
 	struct drm_device *dev = hdmi->dev;
 	static const uint32_t nack[] = {
 			HDMI_DDC_SW_STATUS_NACK0, HDMI_DDC_SW_STATUS_NACK1,
 			HDMI_DDC_SW_STATUS_NACK2, HDMI_DDC_SW_STATUS_NACK3,
 	};
 	int indices[MAX_TRANSACTIONS];
 	int ret, i, j, index = 0;
 	uint32_t ddc_status, ddc_data, i2c_trans;

 	num = min(num, MAX_TRANSACTIONS);

 	WARN_ON(!(hdmi_read(hdmi, REG_HDMI_CTRL) & HDMI_CTRL_ENABLE));

 	if (num == 0)
 		return num;

 	init_ddc(hdmi_i2c);

 	ret = ddc_clear_irq(hdmi_i2c);
 	if (ret)
 		return ret;

 	for (i = 0; i < num; i++) {
 		struct i2c_msg *p = &msgs[i];
 		uint32_t raw_addr = p->addr << 1;

 		if (p->flags & I2C_M_RD)
 			raw_addr |= 1;

 		ddc_data = HDMI_DDC_DATA_DATA(raw_addr) |
 				HDMI_DDC_DATA_DATA_RW(DDC_WRITE);

 		if (i == 0) {
 			ddc_data |= HDMI_DDC_DATA_INDEX(0) |
 					HDMI_DDC_DATA_INDEX_WRITE;
 		}

 		hdmi_write(hdmi, REG_HDMI_DDC_DATA, ddc_data);
 		index++;

 		indices[i] = index;

 		if (p->flags & I2C_M_RD) {
 			index += p->len;
 		} else {
 			for (j = 0; j < p->len; j++) {
 				ddc_data = HDMI_DDC_DATA_DATA(p->buf[j]) |
 						HDMI_DDC_DATA_DATA_RW(DDC_WRITE);
 				hdmi_write(hdmi, REG_HDMI_DDC_DATA, ddc_data);
 				index++;
 			}
 		}

 		i2c_trans = HDMI_I2C_TRANSACTION_REG_CNT(p->len) |
 				HDMI_I2C_TRANSACTION_REG_RW(
 						(p->flags & I2C_M_RD) ? DDC_READ : DDC_WRITE) |
 				HDMI_I2C_TRANSACTION_REG_START;

 		if (i == (num - 1))
 			i2c_trans |= HDMI_I2C_TRANSACTION_REG_STOP;

 		hdmi_write(hdmi, REG_HDMI_I2C_TRANSACTION(i), i2c_trans);
 	}

 	/* trigger the transfer: */
 	hdmi_write(hdmi, REG_HDMI_DDC_CTRL,
 			HDMI_DDC_CTRL_TRANSACTION_CNT(num - 1) |
 			HDMI_DDC_CTRL_GO);

 	ret = wait_event_timeout(hdmi_i2c->ddc_event, sw_done(hdmi_i2c), HZ/4);
 	if (ret <= 0) {
 		if (ret == 0)
 			ret = -ETIMEDOUT;
 		dev_warn(dev->dev, "DDC timeout: %d\n", ret);
 		DBG("sw_status=%08x, hw_status=%08x, int_ctrl=%08x",
 				hdmi_read(hdmi, REG_HDMI_DDC_SW_STATUS),
 				hdmi_read(hdmi, REG_HDMI_DDC_HW_STATUS),
 				hdmi_read(hdmi, REG_HDMI_DDC_INT_CTRL));
 		return ret;
 	}

 	ddc_status = hdmi_read(hdmi, REG_HDMI_DDC_SW_STATUS);

 	/* read back results of any read transactions: */
 	for (i = 0; i < num; i++) {
 		struct i2c_msg *p = &msgs[i];

 		if (!(p->flags & I2C_M_RD))
 			continue;

 		/* check for NACK: */
 		if (ddc_status & nack[i]) {
 			DBG("ddc_status=%08x", ddc_status);
 			break;
 		}

 		ddc_data = HDMI_DDC_DATA_DATA_RW(DDC_READ) |
 				HDMI_DDC_DATA_INDEX(indices[i]) |
 				HDMI_DDC_DATA_INDEX_WRITE;

 		hdmi_write(hdmi, REG_HDMI_DDC_DATA, ddc_data);

 		/* discard first byte: */
 		hdmi_read(hdmi, REG_HDMI_DDC_DATA);

 		for (j = 0; j < p->len; j++) {
 			ddc_data = hdmi_read(hdmi, REG_HDMI_DDC_DATA);
 			p->buf[j] = FIELD(ddc_data, HDMI_DDC_DATA_DATA);
 		}
 	}

 	return i;
 }

 static u32 msm_hdmi_i2c_func(struct i2c_adapter *adapter)
 {
 	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
 }

 static const struct i2c_algorithm msm_hdmi_i2c_algorithm = {
 	.master_xfer	= msm_hdmi_i2c_xfer,
 	.functionality	= msm_hdmi_i2c_func,
 };

 void msm_hdmi_i2c_irq(struct i2c_adapter *i2c)
 {
 	struct hdmi_i2c_adapter *hdmi_i2c = to_hdmi_i2c_adapter(i2c);

 	if (sw_done(hdmi_i2c))
 		wake_up_all(&hdmi_i2c->ddc_event);
 }

 void msm_hdmi_i2c_destroy(struct i2c_adapter *i2c)
 {
 	struct hdmi_i2c_adapter *hdmi_i2c = to_hdmi_i2c_adapter(i2c);
 	i2c_del_adapter(i2c);
 	kfree(hdmi_i2c);
 }

 struct i2c_adapter *msm_hdmi_i2c_init(struct hdmi *hdmi)
 {
 	struct hdmi_i2c_adapter *hdmi_i2c;
 	struct i2c_adapter *i2c = NULL;
 	int ret;

 	hdmi_i2c = kzalloc(sizeof(*hdmi_i2c), GFP_KERNEL);
 	if (!hdmi_i2c) {
 		ret = -ENOMEM;
 		goto fail;
 	}

 	i2c = &hdmi_i2c->base;

 	hdmi_i2c->hdmi = hdmi;
 	init_waitqueue_head(&hdmi_i2c->ddc_event);


 	i2c->owner = THIS_MODULE;
 	i2c->class = I2C_CLASS_DDC;
 	snprintf(i2c->name, sizeof(i2c->name), "msm hdmi i2c");
 	i2c->dev.parent = &hdmi->pdev->dev;
 	i2c->algo = &msm_hdmi_i2c_algorithm;

 	ret = i2c_add_adapter(i2c);
 	if (ret)
 		goto fail;

 	return i2c;

 fail:
 	if (i2c)
 		msm_hdmi_i2c_destroy(i2c);
 	return ERR_PTR(ret);
 }
	/*
	* Copyright (C) 2013 Red Hat
	* 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 "hdmi.h"

	struct hdmi_i2c_adapter {
	struct i2c_adapter base;
	struct hdmi *hdmi;
	bool sw_done;
	wait_queue_head_t ddc_event;
	};
	#define to_hdmi_i2c_adapter(x) container_of(x, struct hdmi_i2c_adapter, base)

	static void init_ddc(struct hdmi_i2c_adapter *hdmi_i2c)
	{
	struct hdmi *hdmi = hdmi_i2c->hdmi;

	hdmi_write(hdmi, REG_HDMI_DDC_CTRL,
	HDMI_DDC_CTRL_SW_STATUS_RESET);
	hdmi_write(hdmi, REG_HDMI_DDC_CTRL,
	HDMI_DDC_CTRL_SOFT_RESET);

	hdmi_write(hdmi, REG_HDMI_DDC_SPEED,
	HDMI_DDC_SPEED_THRESHOLD(2) \|
	HDMI_DDC_SPEED_PRESCALE(10));

	hdmi_write(hdmi, REG_HDMI_DDC_SETUP,
	HDMI_DDC_SETUP_TIMEOUT(0xff));

	/* enable reference timer for 27us */
	hdmi_write(hdmi, REG_HDMI_DDC_REF,
	HDMI_DDC_REF_REFTIMER_ENABLE \|
	HDMI_DDC_REF_REFTIMER(27));
	}

	static int ddc_clear_irq(struct hdmi_i2c_adapter *hdmi_i2c)
	{
	struct hdmi *hdmi = hdmi_i2c->hdmi;
	struct drm_device *dev = hdmi->dev;
	uint32_t retry = 0xffff;
	uint32_t ddc_int_ctrl;

	do {
	--retry;

	hdmi_write(hdmi, REG_HDMI_DDC_INT_CTRL,
	HDMI_DDC_INT_CTRL_SW_DONE_ACK \|
	HDMI_DDC_INT_CTRL_SW_DONE_MASK);

	ddc_int_ctrl = hdmi_read(hdmi, REG_HDMI_DDC_INT_CTRL);

	} while ((ddc_int_ctrl & HDMI_DDC_INT_CTRL_SW_DONE_INT) && retry);

	if (!retry) {
	DRM_DEV_ERROR(dev->dev, "timeout waiting for DDC\n");
	return -ETIMEDOUT;
	}

	hdmi_i2c->sw_done = false;

	return 0;
	}

	#define MAX_TRANSACTIONS 4

	static bool sw_done(struct hdmi_i2c_adapter *hdmi_i2c)
	{
	struct hdmi *hdmi = hdmi_i2c->hdmi;

	if (!hdmi_i2c->sw_done) {
	uint32_t ddc_int_ctrl;

	ddc_int_ctrl = hdmi_read(hdmi, REG_HDMI_DDC_INT_CTRL);

	if ((ddc_int_ctrl & HDMI_DDC_INT_CTRL_SW_DONE_MASK) &&
	(ddc_int_ctrl & HDMI_DDC_INT_CTRL_SW_DONE_INT)) {
	hdmi_i2c->sw_done = true;
	hdmi_write(hdmi, REG_HDMI_DDC_INT_CTRL,
	HDMI_DDC_INT_CTRL_SW_DONE_ACK);
	}
	}

	return hdmi_i2c->sw_done;
	}

	static int msm_hdmi_i2c_xfer(struct i2c_adapter *i2c,
	struct i2c_msg *msgs, int num)
	{
	struct hdmi_i2c_adapter *hdmi_i2c = to_hdmi_i2c_adapter(i2c);
	struct hdmi *hdmi = hdmi_i2c->hdmi;
	struct drm_device *dev = hdmi->dev;
	static const uint32_t nack[] = {
	HDMI_DDC_SW_STATUS_NACK0, HDMI_DDC_SW_STATUS_NACK1,
	HDMI_DDC_SW_STATUS_NACK2, HDMI_DDC_SW_STATUS_NACK3,
	};
	int indices[MAX_TRANSACTIONS];
	int ret, i, j, index = 0;
	uint32_t ddc_status, ddc_data, i2c_trans;

	num = min(num, MAX_TRANSACTIONS);

	WARN_ON(!(hdmi_read(hdmi, REG_HDMI_CTRL) & HDMI_CTRL_ENABLE));

	if (num == 0)
	return num;

	init_ddc(hdmi_i2c);

	ret = ddc_clear_irq(hdmi_i2c);
	if (ret)
	return ret;

	for (i = 0; i < num; i++) {
	struct i2c_msg *p = &msgs[i];
	uint32_t raw_addr = p->addr << 1;

	if (p->flags & I2C_M_RD)
	raw_addr \|= 1;

	ddc_data = HDMI_DDC_DATA_DATA(raw_addr) \|
	HDMI_DDC_DATA_DATA_RW(DDC_WRITE);

	if (i == 0) {
	ddc_data \|= HDMI_DDC_DATA_INDEX(0) \|
	HDMI_DDC_DATA_INDEX_WRITE;
	}

	hdmi_write(hdmi, REG_HDMI_DDC_DATA, ddc_data);
	index++;

	indices[i] = index;

	if (p->flags & I2C_M_RD) {
	index += p->len;
	} else {
	for (j = 0; j < p->len; j++) {
	ddc_data = HDMI_DDC_DATA_DATA(p->buf[j]) \|
	HDMI_DDC_DATA_DATA_RW(DDC_WRITE);
	hdmi_write(hdmi, REG_HDMI_DDC_DATA, ddc_data);
	index++;
	}
	}

	i2c_trans = HDMI_I2C_TRANSACTION_REG_CNT(p->len) \|
	HDMI_I2C_TRANSACTION_REG_RW(
	(p->flags & I2C_M_RD) ? DDC_READ : DDC_WRITE) \|
	HDMI_I2C_TRANSACTION_REG_START;

	if (i == (num - 1))
	i2c_trans \|= HDMI_I2C_TRANSACTION_REG_STOP;

	hdmi_write(hdmi, REG_HDMI_I2C_TRANSACTION(i), i2c_trans);
	}

	/* trigger the transfer: */
	hdmi_write(hdmi, REG_HDMI_DDC_CTRL,
	HDMI_DDC_CTRL_TRANSACTION_CNT(num - 1) \|
	HDMI_DDC_CTRL_GO);

	ret = wait_event_timeout(hdmi_i2c->ddc_event, sw_done(hdmi_i2c), HZ/4);
	if (ret <= 0) {
	if (ret == 0)
	ret = -ETIMEDOUT;
	dev_warn(dev->dev, "DDC timeout: %d\n", ret);
	DBG("sw_status=%08x, hw_status=%08x, int_ctrl=%08x",
	hdmi_read(hdmi, REG_HDMI_DDC_SW_STATUS),
	hdmi_read(hdmi, REG_HDMI_DDC_HW_STATUS),
	hdmi_read(hdmi, REG_HDMI_DDC_INT_CTRL));
	return ret;
	}

	ddc_status = hdmi_read(hdmi, REG_HDMI_DDC_SW_STATUS);

	/* read back results of any read transactions: */
	for (i = 0; i < num; i++) {
	struct i2c_msg *p = &msgs[i];

	if (!(p->flags & I2C_M_RD))
	continue;

	/* check for NACK: */
	if (ddc_status & nack[i]) {
	DBG("ddc_status=%08x", ddc_status);
	break;
	}

	ddc_data = HDMI_DDC_DATA_DATA_RW(DDC_READ) \|
	HDMI_DDC_DATA_INDEX(indices[i]) \|
	HDMI_DDC_DATA_INDEX_WRITE;

	hdmi_write(hdmi, REG_HDMI_DDC_DATA, ddc_data);

	/* discard first byte: */
	hdmi_read(hdmi, REG_HDMI_DDC_DATA);

	for (j = 0; j < p->len; j++) {
	ddc_data = hdmi_read(hdmi, REG_HDMI_DDC_DATA);
	p->buf[j] = FIELD(ddc_data, HDMI_DDC_DATA_DATA);
	}
	}

	return i;
	}

	static u32 msm_hdmi_i2c_func(struct i2c_adapter *adapter)
	{
	return I2C_FUNC_I2C \| I2C_FUNC_SMBUS_EMUL;
	}

	static const struct i2c_algorithm msm_hdmi_i2c_algorithm = {
	.master_xfer = msm_hdmi_i2c_xfer,
	.functionality = msm_hdmi_i2c_func,
	};

	void msm_hdmi_i2c_irq(struct i2c_adapter *i2c)
	{
	struct hdmi_i2c_adapter *hdmi_i2c = to_hdmi_i2c_adapter(i2c);

	if (sw_done(hdmi_i2c))
	wake_up_all(&hdmi_i2c->ddc_event);
	}

	void msm_hdmi_i2c_destroy(struct i2c_adapter *i2c)
	{
	struct hdmi_i2c_adapter *hdmi_i2c = to_hdmi_i2c_adapter(i2c);
	i2c_del_adapter(i2c);
	kfree(hdmi_i2c);
	}

	struct i2c_adapter msm_hdmi_i2c_init(struct hdmi hdmi)
	{
	struct hdmi_i2c_adapter *hdmi_i2c;
	struct i2c_adapter *i2c = NULL;
	int ret;

	hdmi_i2c = kzalloc(sizeof(*hdmi_i2c), GFP_KERNEL);
	if (!hdmi_i2c) {
	ret = -ENOMEM;
	goto fail;
	}

	i2c = &hdmi_i2c->base;

	hdmi_i2c->hdmi = hdmi;
	init_waitqueue_head(&hdmi_i2c->ddc_event);


	i2c->owner = THIS_MODULE;
	i2c->class = I2C_CLASS_DDC;
	snprintf(i2c->name, sizeof(i2c->name), "msm hdmi i2c");
	i2c->dev.parent = &hdmi->pdev->dev;
	i2c->algo = &msm_hdmi_i2c_algorithm;

	ret = i2c_add_adapter(i2c);
	if (ret)
	goto fail;

	return i2c;

	fail:
	if (i2c)
	msm_hdmi_i2c_destroy(i2c);
	return ERR_PTR(ret);
	}