drivers/media/pci/solo6x10/solo6x10-i2c.c - codeaurora/cp-linux - Gitiles

 /*
  * Copyright (C) 2010-2013 Bluecherry, LLC <http://www.bluecherrydvr.com>
  *
  * Original author:
  * Ben Collins <bcollins@ubuntu.com>
  *
  * Additional work by:
  * John Brooks <john.brooks@bluecherry.net>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation; either version 2 of the License, or
  * (at your option) any later version.
  *
  * 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.
  */

 /* XXX: The SOLO6x10 i2c does not have separate interrupts for each i2c
  * channel. The bus can only handle one i2c event at a time. The below handles
  * this all wrong. We should be using the status registers to see if the bus
  * is in use, and have a global lock to check the status register. Also,
  * the bulk of the work should be handled out-of-interrupt. The ugly loops
  * that occur during interrupt scare me. The ISR should merely signal
  * thread context, ACK the interrupt, and move on. -- BenC */

 #include <linux/kernel.h>

 #include "solo6x10.h"

 u8 solo_i2c_readbyte(struct solo_dev *solo_dev, int id, u8 addr, u8 off)
 {
 	struct i2c_msg msgs[2];
 	u8 data;

 	msgs[0].flags = 0;
 	msgs[0].addr = addr;
 	msgs[0].len = 1;
 	msgs[0].buf = &off;

 	msgs[1].flags = I2C_M_RD;
 	msgs[1].addr = addr;
 	msgs[1].len = 1;
 	msgs[1].buf = &data;

 	i2c_transfer(&solo_dev->i2c_adap[id], msgs, 2);

 	return data;
 }

 void solo_i2c_writebyte(struct solo_dev *solo_dev, int id, u8 addr,
 			u8 off, u8 data)
 {
 	struct i2c_msg msgs;
 	u8 buf[2];

 	buf[0] = off;
 	buf[1] = data;
 	msgs.flags = 0;
 	msgs.addr = addr;
 	msgs.len = 2;
 	msgs.buf = buf;

 	i2c_transfer(&solo_dev->i2c_adap[id], &msgs, 1);
 }

 static void solo_i2c_flush(struct solo_dev *solo_dev, int wr)
 {
 	u32 ctrl;

 	ctrl = SOLO_IIC_CH_SET(solo_dev->i2c_id);

 	if (solo_dev->i2c_state == IIC_STATE_START)
 		ctrl |= SOLO_IIC_START;

 	if (wr) {
 		ctrl |= SOLO_IIC_WRITE;
 	} else {
 		ctrl |= SOLO_IIC_READ;
 		if (!(solo_dev->i2c_msg->flags & I2C_M_NO_RD_ACK))
 			ctrl |= SOLO_IIC_ACK_EN;
 	}

 	if (solo_dev->i2c_msg_ptr == solo_dev->i2c_msg->len)
 		ctrl |= SOLO_IIC_STOP;

 	solo_reg_write(solo_dev, SOLO_IIC_CTRL, ctrl);
 }

 static void solo_i2c_start(struct solo_dev *solo_dev)
 {
 	u32 addr = solo_dev->i2c_msg->addr << 1;

 	if (solo_dev->i2c_msg->flags & I2C_M_RD)
 		addr |= 1;

 	solo_dev->i2c_state = IIC_STATE_START;
 	solo_reg_write(solo_dev, SOLO_IIC_TXD, addr);
 	solo_i2c_flush(solo_dev, 1);
 }

 static void solo_i2c_stop(struct solo_dev *solo_dev)
 {
 	solo_irq_off(solo_dev, SOLO_IRQ_IIC);
 	solo_reg_write(solo_dev, SOLO_IIC_CTRL, 0);
 	solo_dev->i2c_state = IIC_STATE_STOP;
 	wake_up(&solo_dev->i2c_wait);
 }

 static int solo_i2c_handle_read(struct solo_dev *solo_dev)
 {
 prepare_read:
 	if (solo_dev->i2c_msg_ptr != solo_dev->i2c_msg->len) {
 		solo_i2c_flush(solo_dev, 0);
 		return 0;
 	}

 	solo_dev->i2c_msg_ptr = 0;
 	solo_dev->i2c_msg++;
 	solo_dev->i2c_msg_num--;

 	if (solo_dev->i2c_msg_num == 0) {
 		solo_i2c_stop(solo_dev);
 		return 0;
 	}

 	if (!(solo_dev->i2c_msg->flags & I2C_M_NOSTART)) {
 		solo_i2c_start(solo_dev);
 	} else {
 		if (solo_dev->i2c_msg->flags & I2C_M_RD)
 			goto prepare_read;
 		else
 			solo_i2c_stop(solo_dev);
 	}

 	return 0;
 }

 static int solo_i2c_handle_write(struct solo_dev *solo_dev)
 {
 retry_write:
 	if (solo_dev->i2c_msg_ptr != solo_dev->i2c_msg->len) {
 		solo_reg_write(solo_dev, SOLO_IIC_TXD,
 			       solo_dev->i2c_msg->buf[solo_dev->i2c_msg_ptr]);
 		solo_dev->i2c_msg_ptr++;
 		solo_i2c_flush(solo_dev, 1);
 		return 0;
 	}

 	solo_dev->i2c_msg_ptr = 0;
 	solo_dev->i2c_msg++;
 	solo_dev->i2c_msg_num--;

 	if (solo_dev->i2c_msg_num == 0) {
 		solo_i2c_stop(solo_dev);
 		return 0;
 	}

 	if (!(solo_dev->i2c_msg->flags & I2C_M_NOSTART)) {
 		solo_i2c_start(solo_dev);
 	} else {
 		if (solo_dev->i2c_msg->flags & I2C_M_RD)
 			solo_i2c_stop(solo_dev);
 		else
 			goto retry_write;
 	}

 	return 0;
 }

 int solo_i2c_isr(struct solo_dev *solo_dev)
 {
 	u32 status = solo_reg_read(solo_dev, SOLO_IIC_CTRL);
 	int ret = -EINVAL;


 	if (CHK_FLAGS(status, SOLO_IIC_STATE_TRNS | SOLO_IIC_STATE_SIG_ERR)
 	    || solo_dev->i2c_id < 0) {
 		solo_i2c_stop(solo_dev);
 		return -ENXIO;
 	}

 	switch (solo_dev->i2c_state) {
 	case IIC_STATE_START:
 		if (solo_dev->i2c_msg->flags & I2C_M_RD) {
 			solo_dev->i2c_state = IIC_STATE_READ;
 			ret = solo_i2c_handle_read(solo_dev);
 			break;
 		}

 		solo_dev->i2c_state = IIC_STATE_WRITE;
 	case IIC_STATE_WRITE:
 		ret = solo_i2c_handle_write(solo_dev);
 		break;

 	case IIC_STATE_READ:
 		solo_dev->i2c_msg->buf[solo_dev->i2c_msg_ptr] =
 			solo_reg_read(solo_dev, SOLO_IIC_RXD);
 		solo_dev->i2c_msg_ptr++;

 		ret = solo_i2c_handle_read(solo_dev);
 		break;

 	default:
 		solo_i2c_stop(solo_dev);
 	}

 	return ret;
 }

 static int solo_i2c_master_xfer(struct i2c_adapter *adap,
 				struct i2c_msg msgs[], int num)
 {
 	struct solo_dev *solo_dev = adap->algo_data;
 	unsigned long timeout;
 	int ret;
 	int i;
 	DEFINE_WAIT(wait);

 	for (i = 0; i < SOLO_I2C_ADAPTERS; i++) {
 		if (&solo_dev->i2c_adap[i] == adap)
 			break;
 	}

 	if (i == SOLO_I2C_ADAPTERS)
 		return num; /* XXX Right return value for failure? */

 	mutex_lock(&solo_dev->i2c_mutex);
 	solo_dev->i2c_id = i;
 	solo_dev->i2c_msg = msgs;
 	solo_dev->i2c_msg_num = num;
 	solo_dev->i2c_msg_ptr = 0;

 	solo_reg_write(solo_dev, SOLO_IIC_CTRL, 0);
 	solo_irq_on(solo_dev, SOLO_IRQ_IIC);
 	solo_i2c_start(solo_dev);

 	timeout = HZ / 2;

 	for (;;) {
 		prepare_to_wait(&solo_dev->i2c_wait, &wait,
 				TASK_INTERRUPTIBLE);

 		if (solo_dev->i2c_state == IIC_STATE_STOP)
 			break;

 		timeout = schedule_timeout(timeout);
 		if (!timeout)
 			break;

 		if (signal_pending(current))
 			break;
 	}

 	finish_wait(&solo_dev->i2c_wait, &wait);
 	ret = num - solo_dev->i2c_msg_num;
 	solo_dev->i2c_state = IIC_STATE_IDLE;
 	solo_dev->i2c_id = -1;

 	mutex_unlock(&solo_dev->i2c_mutex);

 	return ret;
 }

 static u32 solo_i2c_functionality(struct i2c_adapter *adap)
 {
 	return I2C_FUNC_I2C;
 }

 static const struct i2c_algorithm solo_i2c_algo = {
 	.master_xfer	= solo_i2c_master_xfer,
 	.functionality	= solo_i2c_functionality,
 };

 int solo_i2c_init(struct solo_dev *solo_dev)
 {
 	int i;
 	int ret;

 	solo_reg_write(solo_dev, SOLO_IIC_CFG,
 		       SOLO_IIC_PRESCALE(8) | SOLO_IIC_ENABLE);

 	solo_dev->i2c_id = -1;
 	solo_dev->i2c_state = IIC_STATE_IDLE;
 	init_waitqueue_head(&solo_dev->i2c_wait);
 	mutex_init(&solo_dev->i2c_mutex);

 	for (i = 0; i < SOLO_I2C_ADAPTERS; i++) {
 		struct i2c_adapter *adap = &solo_dev->i2c_adap[i];

 		snprintf(adap->name, I2C_NAME_SIZE, "%s I2C %d",
 			 SOLO6X10_NAME, i);
 		adap->algo = &solo_i2c_algo;
 		adap->algo_data = solo_dev;
 		adap->retries = 1;
 		adap->dev.parent = &solo_dev->pdev->dev;

 		ret = i2c_add_adapter(adap);
 		if (ret) {
 			adap->algo_data = NULL;
 			break;
 		}
 	}

 	if (ret) {
 		for (i = 0; i < SOLO_I2C_ADAPTERS; i++) {
 			if (!solo_dev->i2c_adap[i].algo_data)
 				break;
 			i2c_del_adapter(&solo_dev->i2c_adap[i]);
 			solo_dev->i2c_adap[i].algo_data = NULL;
 		}
 		return ret;
 	}

 	return 0;
 }

 void solo_i2c_exit(struct solo_dev *solo_dev)
 {
 	int i;

 	for (i = 0; i < SOLO_I2C_ADAPTERS; i++) {
 		if (!solo_dev->i2c_adap[i].algo_data)
 			continue;
 		i2c_del_adapter(&solo_dev->i2c_adap[i]);
 		solo_dev->i2c_adap[i].algo_data = NULL;
 	}
 }
	/*
	* Copyright (C) 2010-2013 Bluecherry, LLC <http://www.bluecherrydvr.com>
	*
	* Original author:
	* Ben Collins <bcollins@ubuntu.com>
	*
	* Additional work by:
	* John Brooks <john.brooks@bluecherry.net>
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation; either version 2 of the License, or
	* (at your option) any later version.
	*
	* 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.
	*/

	/* XXX: The SOLO6x10 i2c does not have separate interrupts for each i2c
	* channel. The bus can only handle one i2c event at a time. The below handles
	* this all wrong. We should be using the status registers to see if the bus
	* is in use, and have a global lock to check the status register. Also,
	* the bulk of the work should be handled out-of-interrupt. The ugly loops
	* that occur during interrupt scare me. The ISR should merely signal
	* thread context, ACK the interrupt, and move on. -- BenC */

	#include <linux/kernel.h>

	#include "solo6x10.h"

	u8 solo_i2c_readbyte(struct solo_dev *solo_dev, int id, u8 addr, u8 off)
	{
	struct i2c_msg msgs[2];
	u8 data;

	msgs[0].flags = 0;
	msgs[0].addr = addr;
	msgs[0].len = 1;
	msgs[0].buf = &off;

	msgs[1].flags = I2C_M_RD;
	msgs[1].addr = addr;
	msgs[1].len = 1;
	msgs[1].buf = &data;

	i2c_transfer(&solo_dev->i2c_adap[id], msgs, 2);

	return data;
	}

	void solo_i2c_writebyte(struct solo_dev *solo_dev, int id, u8 addr,
	u8 off, u8 data)
	{
	struct i2c_msg msgs;
	u8 buf[2];

	buf[0] = off;
	buf[1] = data;
	msgs.flags = 0;
	msgs.addr = addr;
	msgs.len = 2;
	msgs.buf = buf;

	i2c_transfer(&solo_dev->i2c_adap[id], &msgs, 1);
	}

	static void solo_i2c_flush(struct solo_dev *solo_dev, int wr)
	{
	u32 ctrl;

	ctrl = SOLO_IIC_CH_SET(solo_dev->i2c_id);

	if (solo_dev->i2c_state == IIC_STATE_START)
	ctrl \|= SOLO_IIC_START;

	if (wr) {
	ctrl \|= SOLO_IIC_WRITE;
	} else {
	ctrl \|= SOLO_IIC_READ;
	if (!(solo_dev->i2c_msg->flags & I2C_M_NO_RD_ACK))
	ctrl \|= SOLO_IIC_ACK_EN;
	}

	if (solo_dev->i2c_msg_ptr == solo_dev->i2c_msg->len)
	ctrl \|= SOLO_IIC_STOP;

	solo_reg_write(solo_dev, SOLO_IIC_CTRL, ctrl);
	}

	static void solo_i2c_start(struct solo_dev *solo_dev)
	{
	u32 addr = solo_dev->i2c_msg->addr << 1;

	if (solo_dev->i2c_msg->flags & I2C_M_RD)
	addr \|= 1;

	solo_dev->i2c_state = IIC_STATE_START;
	solo_reg_write(solo_dev, SOLO_IIC_TXD, addr);
	solo_i2c_flush(solo_dev, 1);
	}

	static void solo_i2c_stop(struct solo_dev *solo_dev)
	{
	solo_irq_off(solo_dev, SOLO_IRQ_IIC);
	solo_reg_write(solo_dev, SOLO_IIC_CTRL, 0);
	solo_dev->i2c_state = IIC_STATE_STOP;
	wake_up(&solo_dev->i2c_wait);
	}

	static int solo_i2c_handle_read(struct solo_dev *solo_dev)
	{
	prepare_read:
	if (solo_dev->i2c_msg_ptr != solo_dev->i2c_msg->len) {
	solo_i2c_flush(solo_dev, 0);
	return 0;
	}

	solo_dev->i2c_msg_ptr = 0;
	solo_dev->i2c_msg++;
	solo_dev->i2c_msg_num--;

	if (solo_dev->i2c_msg_num == 0) {
	solo_i2c_stop(solo_dev);
	return 0;
	}

	if (!(solo_dev->i2c_msg->flags & I2C_M_NOSTART)) {
	solo_i2c_start(solo_dev);
	} else {
	if (solo_dev->i2c_msg->flags & I2C_M_RD)
	goto prepare_read;
	else
	solo_i2c_stop(solo_dev);
	}

	return 0;
	}

	static int solo_i2c_handle_write(struct solo_dev *solo_dev)
	{
	retry_write:
	if (solo_dev->i2c_msg_ptr != solo_dev->i2c_msg->len) {
	solo_reg_write(solo_dev, SOLO_IIC_TXD,
	solo_dev->i2c_msg->buf[solo_dev->i2c_msg_ptr]);
	solo_dev->i2c_msg_ptr++;
	solo_i2c_flush(solo_dev, 1);
	return 0;
	}

	solo_dev->i2c_msg_ptr = 0;
	solo_dev->i2c_msg++;
	solo_dev->i2c_msg_num--;

	if (solo_dev->i2c_msg_num == 0) {
	solo_i2c_stop(solo_dev);
	return 0;
	}

	if (!(solo_dev->i2c_msg->flags & I2C_M_NOSTART)) {
	solo_i2c_start(solo_dev);
	} else {
	if (solo_dev->i2c_msg->flags & I2C_M_RD)
	solo_i2c_stop(solo_dev);
	else
	goto retry_write;
	}

	return 0;
	}

	int solo_i2c_isr(struct solo_dev *solo_dev)
	{
	u32 status = solo_reg_read(solo_dev, SOLO_IIC_CTRL);
	int ret = -EINVAL;


	if (CHK_FLAGS(status, SOLO_IIC_STATE_TRNS \| SOLO_IIC_STATE_SIG_ERR)
	\|\| solo_dev->i2c_id < 0) {
	solo_i2c_stop(solo_dev);
	return -ENXIO;
	}

	switch (solo_dev->i2c_state) {
	case IIC_STATE_START:
	if (solo_dev->i2c_msg->flags & I2C_M_RD) {
	solo_dev->i2c_state = IIC_STATE_READ;
	ret = solo_i2c_handle_read(solo_dev);
	break;
	}

	solo_dev->i2c_state = IIC_STATE_WRITE;
	case IIC_STATE_WRITE:
	ret = solo_i2c_handle_write(solo_dev);
	break;

	case IIC_STATE_READ:
	solo_dev->i2c_msg->buf[solo_dev->i2c_msg_ptr] =
	solo_reg_read(solo_dev, SOLO_IIC_RXD);
	solo_dev->i2c_msg_ptr++;

	ret = solo_i2c_handle_read(solo_dev);
	break;

	default:
	solo_i2c_stop(solo_dev);
	}

	return ret;
	}

	static int solo_i2c_master_xfer(struct i2c_adapter *adap,
	struct i2c_msg msgs[], int num)
	{
	struct solo_dev *solo_dev = adap->algo_data;
	unsigned long timeout;
	int ret;
	int i;
	DEFINE_WAIT(wait);

	for (i = 0; i < SOLO_I2C_ADAPTERS; i++) {
	if (&solo_dev->i2c_adap[i] == adap)
	break;
	}

	if (i == SOLO_I2C_ADAPTERS)
	return num; /* XXX Right return value for failure? */

	mutex_lock(&solo_dev->i2c_mutex);
	solo_dev->i2c_id = i;
	solo_dev->i2c_msg = msgs;
	solo_dev->i2c_msg_num = num;
	solo_dev->i2c_msg_ptr = 0;

	solo_reg_write(solo_dev, SOLO_IIC_CTRL, 0);
	solo_irq_on(solo_dev, SOLO_IRQ_IIC);
	solo_i2c_start(solo_dev);

	timeout = HZ / 2;

	for (;;) {
	prepare_to_wait(&solo_dev->i2c_wait, &wait,
	TASK_INTERRUPTIBLE);

	if (solo_dev->i2c_state == IIC_STATE_STOP)
	break;

	timeout = schedule_timeout(timeout);
	if (!timeout)
	break;

	if (signal_pending(current))
	break;
	}

	finish_wait(&solo_dev->i2c_wait, &wait);
	ret = num - solo_dev->i2c_msg_num;
	solo_dev->i2c_state = IIC_STATE_IDLE;
	solo_dev->i2c_id = -1;

	mutex_unlock(&solo_dev->i2c_mutex);

	return ret;
	}

	static u32 solo_i2c_functionality(struct i2c_adapter *adap)
	{
	return I2C_FUNC_I2C;
	}

	static const struct i2c_algorithm solo_i2c_algo = {
	.master_xfer = solo_i2c_master_xfer,
	.functionality = solo_i2c_functionality,
	};

	int solo_i2c_init(struct solo_dev *solo_dev)
	{
	int i;
	int ret;

	solo_reg_write(solo_dev, SOLO_IIC_CFG,
	SOLO_IIC_PRESCALE(8) \| SOLO_IIC_ENABLE);

	solo_dev->i2c_id = -1;
	solo_dev->i2c_state = IIC_STATE_IDLE;
	init_waitqueue_head(&solo_dev->i2c_wait);
	mutex_init(&solo_dev->i2c_mutex);

	for (i = 0; i < SOLO_I2C_ADAPTERS; i++) {
	struct i2c_adapter *adap = &solo_dev->i2c_adap[i];

	snprintf(adap->name, I2C_NAME_SIZE, "%s I2C %d",
	SOLO6X10_NAME, i);
	adap->algo = &solo_i2c_algo;
	adap->algo_data = solo_dev;
	adap->retries = 1;
	adap->dev.parent = &solo_dev->pdev->dev;

	ret = i2c_add_adapter(adap);
	if (ret) {
	adap->algo_data = NULL;
	break;
	}
	}

	if (ret) {
	for (i = 0; i < SOLO_I2C_ADAPTERS; i++) {
	if (!solo_dev->i2c_adap[i].algo_data)
	break;
	i2c_del_adapter(&solo_dev->i2c_adap[i]);
	solo_dev->i2c_adap[i].algo_data = NULL;
	}
	return ret;
	}

	return 0;
	}

	void solo_i2c_exit(struct solo_dev *solo_dev)
	{
	int i;

	for (i = 0; i < SOLO_I2C_ADAPTERS; i++) {
	if (!solo_dev->i2c_adap[i].algo_data)
	continue;
	i2c_del_adapter(&solo_dev->i2c_adap[i]);
	solo_dev->i2c_adap[i].algo_data = NULL;
	}
	}