drivers/i2c/busses/i2c-taos-evm.c - kernel/lockdown - Git at Google

 /*
  * Driver for the TAOS evaluation modules
  * These devices include an I2C master which can be controlled over the
  * serial port.
  *
  * Copyright (C) 2007 Jean Delvare <jdelvare@suse.de>
  *
  * 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; version 2 of the License.
  *
  * 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, write to the Free Software
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  */

 #include <linux/delay.h>
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/interrupt.h>
 #include <linux/input.h>
 #include <linux/serio.h>
 #include <linux/init.h>
 #include <linux/i2c.h>

 #define TAOS_BUFFER_SIZE	63

 #define TAOS_STATE_INIT		0
 #define TAOS_STATE_IDLE		1
 #define TAOS_STATE_EOFF		2
 #define TAOS_STATE_RECV		3

 #define TAOS_CMD_RESET		0x12
 #define TAOS_CMD_ECHO_ON	'+'
 #define TAOS_CMD_ECHO_OFF	'-'

 static DECLARE_WAIT_QUEUE_HEAD(wq);

 struct taos_data {
 	struct i2c_adapter adapter;
 	struct i2c_client *client;
 	int state;
 	u8 addr;		/* last used address */
 	unsigned char buffer[TAOS_BUFFER_SIZE];
 	unsigned int pos;	/* position inside the buffer */
 };

 /* TAOS TSL2550 EVM */
 static struct i2c_board_info tsl2550_info = {
 	I2C_BOARD_INFO("tsl2550", 0x39),
 };

 /* Instantiate i2c devices based on the adapter name */
 static struct i2c_client *taos_instantiate_device(struct i2c_adapter *adapter)
 {
 	if (!strncmp(adapter->name, "TAOS TSL2550 EVM", 16)) {
 		dev_info(&adapter->dev, "Instantiating device %s at 0x%02x\n",
 			tsl2550_info.type, tsl2550_info.addr);
 		return i2c_new_device(adapter, &tsl2550_info);
 	}

 	return NULL;
 }

 static int taos_smbus_xfer(struct i2c_adapter *adapter, u16 addr,
 			   unsigned short flags, char read_write, u8 command,
 			   int size, union i2c_smbus_data *data)
 {
 	struct serio *serio = adapter->algo_data;
 	struct taos_data *taos = serio_get_drvdata(serio);
 	char *p;

 	/* Encode our transaction. "@" is for the device address, "$" for the
 	   SMBus command and "#" for the data. */
 	p = taos->buffer;

 	/* The device remembers the last used address, no need to send it
 	   again if it's the same */
 	if (addr != taos->addr)
 		p += sprintf(p, "@%02X", addr);

 	switch (size) {
 	case I2C_SMBUS_BYTE:
 		if (read_write == I2C_SMBUS_WRITE)
 			sprintf(p, "$#%02X", command);
 		else
 			sprintf(p, "$");
 		break;
 	case I2C_SMBUS_BYTE_DATA:
 		if (read_write == I2C_SMBUS_WRITE)
 			sprintf(p, "$%02X#%02X", command, data->byte);
 		else
 			sprintf(p, "$%02X", command);
 		break;
 	default:
 		dev_warn(&adapter->dev, "Unsupported transaction %d\n", size);
 		return -EOPNOTSUPP;
 	}

 	/* Send the transaction to the TAOS EVM */
 	dev_dbg(&adapter->dev, "Command buffer: %s\n", taos->buffer);
 	for (p = taos->buffer; *p; p++)
 		serio_write(serio, *p);

 	taos->addr = addr;

 	/* Start the transaction and read the answer */
 	taos->pos = 0;
 	taos->state = TAOS_STATE_RECV;
 	serio_write(serio, read_write == I2C_SMBUS_WRITE ? '>' : '<');
 	wait_event_interruptible_timeout(wq, taos->state == TAOS_STATE_IDLE,
 					 msecs_to_jiffies(150));
 	if (taos->state != TAOS_STATE_IDLE
 	 || taos->pos != 5) {
 		dev_err(&adapter->dev, "Transaction timeout (pos=%d)\n",
 			taos->pos);
 		return -EIO;
 	}
 	dev_dbg(&adapter->dev, "Answer buffer: %s\n", taos->buffer);

 	/* Interpret the returned string */
 	p = taos->buffer + 1;
 	p[3] = '\0';
 	if (!strcmp(p, "NAK"))
 		return -ENODEV;

 	if (read_write == I2C_SMBUS_WRITE) {
 		if (!strcmp(p, "ACK"))
 			return 0;
 	} else {
 		if (p[0] == 'x') {
 			data->byte = simple_strtol(p + 1, NULL, 16);
 			return 0;
 		}
 	}

 	return -EIO;
 }

 static u32 taos_smbus_func(struct i2c_adapter *adapter)
 {
 	return I2C_FUNC_SMBUS_BYTE | I2C_FUNC_SMBUS_BYTE_DATA;
 }

 static const struct i2c_algorithm taos_algorithm = {
 	.smbus_xfer	= taos_smbus_xfer,
 	.functionality	= taos_smbus_func,
 };

 static irqreturn_t taos_interrupt(struct serio *serio, unsigned char data,
 				  unsigned int flags)
 {
 	struct taos_data *taos = serio_get_drvdata(serio);

 	switch (taos->state) {
 	case TAOS_STATE_INIT:
 		taos->buffer[taos->pos++] = data;
 		if (data == ':'
 		 || taos->pos == TAOS_BUFFER_SIZE - 1) {
 			taos->buffer[taos->pos] = '\0';
 			taos->state = TAOS_STATE_IDLE;
 			wake_up_interruptible(&wq);
 		}
 		break;
 	case TAOS_STATE_EOFF:
 		taos->state = TAOS_STATE_IDLE;
 		wake_up_interruptible(&wq);
 		break;
 	case TAOS_STATE_RECV:
 		taos->buffer[taos->pos++] = data;
 		if (data == ']') {
 			taos->buffer[taos->pos] = '\0';
 			taos->state = TAOS_STATE_IDLE;
 			wake_up_interruptible(&wq);
 		}
 		break;
 	}

 	return IRQ_HANDLED;
 }

 /* Extract the adapter name from the buffer received after reset.
    The buffer is modified and a pointer inside the buffer is returned. */
 static char *taos_adapter_name(char *buffer)
 {
 	char *start, *end;

 	start = strstr(buffer, "TAOS ");
 	if (!start)
 		return NULL;

 	end = strchr(start, '\r');
 	if (!end)
 		return NULL;
 	*end = '\0';

 	return start;
 }

 static int taos_connect(struct serio *serio, struct serio_driver *drv)
 {
 	struct taos_data *taos;
 	struct i2c_adapter *adapter;
 	char *name;
 	int err;

 	taos = kzalloc(sizeof(struct taos_data), GFP_KERNEL);
 	if (!taos) {
 		err = -ENOMEM;
 		goto exit;
 	}
 	taos->state = TAOS_STATE_INIT;
 	serio_set_drvdata(serio, taos);

 	err = serio_open(serio, drv);
 	if (err)
 		goto exit_kfree;

 	adapter = &taos->adapter;
 	adapter->owner = THIS_MODULE;
 	adapter->algo = &taos_algorithm;
 	adapter->algo_data = serio;
 	adapter->dev.parent = &serio->dev;

 	/* Reset the TAOS evaluation module to identify it */
 	serio_write(serio, TAOS_CMD_RESET);
 	wait_event_interruptible_timeout(wq, taos->state == TAOS_STATE_IDLE,
 					 msecs_to_jiffies(2000));

 	if (taos->state != TAOS_STATE_IDLE) {
 		err = -ENODEV;
 		dev_err(&serio->dev, "TAOS EVM reset failed (state=%d, "
 			"pos=%d)\n", taos->state, taos->pos);
 		goto exit_close;
 	}

 	name = taos_adapter_name(taos->buffer);
 	if (!name) {
 		err = -ENODEV;
 		dev_err(&serio->dev, "TAOS EVM identification failed\n");
 		goto exit_close;
 	}
 	strlcpy(adapter->name, name, sizeof(adapter->name));

 	/* Turn echo off for better performance */
 	taos->state = TAOS_STATE_EOFF;
 	serio_write(serio, TAOS_CMD_ECHO_OFF);

 	wait_event_interruptible_timeout(wq, taos->state == TAOS_STATE_IDLE,
 					 msecs_to_jiffies(250));
 	if (taos->state != TAOS_STATE_IDLE) {
 		err = -ENODEV;
 		dev_err(&serio->dev, "TAOS EVM echo off failed "
 			"(state=%d)\n", taos->state);
 		goto exit_close;
 	}

 	err = i2c_add_adapter(adapter);
 	if (err)
 		goto exit_close;
 	dev_info(&serio->dev, "Connected to TAOS EVM\n");

 	taos->client = taos_instantiate_device(adapter);
 	return 0;

  exit_close:
 	serio_close(serio);
  exit_kfree:
 	kfree(taos);
  exit:
 	return err;
 }

 static void taos_disconnect(struct serio *serio)
 {
 	struct taos_data *taos = serio_get_drvdata(serio);

 	if (taos->client)
 		i2c_unregister_device(taos->client);
 	i2c_del_adapter(&taos->adapter);
 	serio_close(serio);
 	kfree(taos);

 	dev_info(&serio->dev, "Disconnected from TAOS EVM\n");
 }

 static struct serio_device_id taos_serio_ids[] = {
 	{
 		.type	= SERIO_RS232,
 		.proto	= SERIO_TAOSEVM,
 		.id	= SERIO_ANY,
 		.extra	= SERIO_ANY,
 	},
 	{ 0 }
 };
 MODULE_DEVICE_TABLE(serio, taos_serio_ids);

 static struct serio_driver taos_drv = {
 	.driver		= {
 		.name	= "taos-evm",
 	},
 	.description	= "TAOS evaluation module driver",
 	.id_table	= taos_serio_ids,
 	.connect	= taos_connect,
 	.disconnect	= taos_disconnect,
 	.interrupt	= taos_interrupt,
 };

 static int __init taos_init(void)
 {
 	return serio_register_driver(&taos_drv);
 }

 static void __exit taos_exit(void)
 {
 	serio_unregister_driver(&taos_drv);
 }

 MODULE_AUTHOR("Jean Delvare <jdelvare@suse.de>");
 MODULE_DESCRIPTION("TAOS evaluation module driver");
 MODULE_LICENSE("GPL");

 module_init(taos_init);
 module_exit(taos_exit);
	/*
	* Driver for the TAOS evaluation modules
	* These devices include an I2C master which can be controlled over the
	* serial port.
	*
	* Copyright (C) 2007 Jean Delvare <jdelvare@suse.de>
	*
	* 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; version 2 of the License.
	*
	* 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, write to the Free Software
	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	*/

	#include <linux/delay.h>
	#include <linux/module.h>
	#include <linux/slab.h>
	#include <linux/interrupt.h>
	#include <linux/input.h>
	#include <linux/serio.h>
	#include <linux/init.h>
	#include <linux/i2c.h>

	#define TAOS_BUFFER_SIZE 63

	#define TAOS_STATE_INIT 0
	#define TAOS_STATE_IDLE 1
	#define TAOS_STATE_EOFF 2
	#define TAOS_STATE_RECV 3

	#define TAOS_CMD_RESET 0x12
	#define TAOS_CMD_ECHO_ON '+'
	#define TAOS_CMD_ECHO_OFF '-'

	static DECLARE_WAIT_QUEUE_HEAD(wq);

	struct taos_data {
	struct i2c_adapter adapter;
	struct i2c_client *client;
	int state;
	u8 addr; /* last used address */
	unsigned char buffer[TAOS_BUFFER_SIZE];
	unsigned int pos; /* position inside the buffer */
	};

	/* TAOS TSL2550 EVM */
	static struct i2c_board_info tsl2550_info = {
	I2C_BOARD_INFO("tsl2550", 0x39),
	};

	/* Instantiate i2c devices based on the adapter name */
	static struct i2c_client taos_instantiate_device(struct i2c_adapter adapter)
	{
	if (!strncmp(adapter->name, "TAOS TSL2550 EVM", 16)) {
	dev_info(&adapter->dev, "Instantiating device %s at 0x%02x\n",
	tsl2550_info.type, tsl2550_info.addr);
	return i2c_new_device(adapter, &tsl2550_info);
	}

	return NULL;
	}

	static int taos_smbus_xfer(struct i2c_adapter *adapter, u16 addr,
	unsigned short flags, char read_write, u8 command,
	int size, union i2c_smbus_data *data)
	{
	struct serio *serio = adapter->algo_data;
	struct taos_data *taos = serio_get_drvdata(serio);
	char *p;

	/* Encode our transaction. "@" is for the device address, "$" for the
	SMBus command and "#" for the data. */
	p = taos->buffer;

	/* The device remembers the last used address, no need to send it
	again if it's the same */
	if (addr != taos->addr)
	p += sprintf(p, "@%02X", addr);

	switch (size) {
	case I2C_SMBUS_BYTE:
	if (read_write == I2C_SMBUS_WRITE)
	sprintf(p, "$#%02X", command);
	else
	sprintf(p, "$");
	break;
	case I2C_SMBUS_BYTE_DATA:
	if (read_write == I2C_SMBUS_WRITE)
	sprintf(p, "$%02X#%02X", command, data->byte);
	else
	sprintf(p, "$%02X", command);
	break;
	default:
	dev_warn(&adapter->dev, "Unsupported transaction %d\n", size);
	return -EOPNOTSUPP;
	}

	/* Send the transaction to the TAOS EVM */
	dev_dbg(&adapter->dev, "Command buffer: %s\n", taos->buffer);
	for (p = taos->buffer; *p; p++)
	serio_write(serio, *p);

	taos->addr = addr;

	/* Start the transaction and read the answer */
	taos->pos = 0;
	taos->state = TAOS_STATE_RECV;
	serio_write(serio, read_write == I2C_SMBUS_WRITE ? '>' : '<');
	wait_event_interruptible_timeout(wq, taos->state == TAOS_STATE_IDLE,
	msecs_to_jiffies(150));
	if (taos->state != TAOS_STATE_IDLE
	\|\| taos->pos != 5) {
	dev_err(&adapter->dev, "Transaction timeout (pos=%d)\n",
	taos->pos);
	return -EIO;
	}
	dev_dbg(&adapter->dev, "Answer buffer: %s\n", taos->buffer);

	/* Interpret the returned string */
	p = taos->buffer + 1;
	p[3] = '\0';
	if (!strcmp(p, "NAK"))
	return -ENODEV;

	if (read_write == I2C_SMBUS_WRITE) {
	if (!strcmp(p, "ACK"))
	return 0;
	} else {
	if (p[0] == 'x') {
	data->byte = simple_strtol(p + 1, NULL, 16);
	return 0;
	}
	}

	return -EIO;
	}

	static u32 taos_smbus_func(struct i2c_adapter *adapter)
	{
	return I2C_FUNC_SMBUS_BYTE \| I2C_FUNC_SMBUS_BYTE_DATA;
	}

	static const struct i2c_algorithm taos_algorithm = {
	.smbus_xfer = taos_smbus_xfer,
	.functionality = taos_smbus_func,
	};

	static irqreturn_t taos_interrupt(struct serio *serio, unsigned char data,
	unsigned int flags)
	{
	struct taos_data *taos = serio_get_drvdata(serio);

	switch (taos->state) {
	case TAOS_STATE_INIT:
	taos->buffer[taos->pos++] = data;
	if (data == ':'
	\|\| taos->pos == TAOS_BUFFER_SIZE - 1) {
	taos->buffer[taos->pos] = '\0';
	taos->state = TAOS_STATE_IDLE;
	wake_up_interruptible(&wq);
	}
	break;
	case TAOS_STATE_EOFF:
	taos->state = TAOS_STATE_IDLE;
	wake_up_interruptible(&wq);
	break;
	case TAOS_STATE_RECV:
	taos->buffer[taos->pos++] = data;
	if (data == ']') {
	taos->buffer[taos->pos] = '\0';
	taos->state = TAOS_STATE_IDLE;
	wake_up_interruptible(&wq);
	}
	break;
	}

	return IRQ_HANDLED;
	}

	/* Extract the adapter name from the buffer received after reset.
	The buffer is modified and a pointer inside the buffer is returned. */
	static char taos_adapter_name(char buffer)
	{
	char start, end;

	start = strstr(buffer, "TAOS ");
	if (!start)
	return NULL;

	end = strchr(start, '\r');
	if (!end)
	return NULL;
	*end = '\0';

	return start;
	}

	static int taos_connect(struct serio serio, struct serio_driver drv)
	{
	struct taos_data *taos;
	struct i2c_adapter *adapter;
	char *name;
	int err;

	taos = kzalloc(sizeof(struct taos_data), GFP_KERNEL);
	if (!taos) {
	err = -ENOMEM;
	goto exit;
	}
	taos->state = TAOS_STATE_INIT;
	serio_set_drvdata(serio, taos);

	err = serio_open(serio, drv);
	if (err)
	goto exit_kfree;

	adapter = &taos->adapter;
	adapter->owner = THIS_MODULE;
	adapter->algo = &taos_algorithm;
	adapter->algo_data = serio;
	adapter->dev.parent = &serio->dev;

	/* Reset the TAOS evaluation module to identify it */
	serio_write(serio, TAOS_CMD_RESET);
	wait_event_interruptible_timeout(wq, taos->state == TAOS_STATE_IDLE,
	msecs_to_jiffies(2000));

	if (taos->state != TAOS_STATE_IDLE) {
	err = -ENODEV;
	dev_err(&serio->dev, "TAOS EVM reset failed (state=%d, "
	"pos=%d)\n", taos->state, taos->pos);
	goto exit_close;
	}

	name = taos_adapter_name(taos->buffer);
	if (!name) {
	err = -ENODEV;
	dev_err(&serio->dev, "TAOS EVM identification failed\n");
	goto exit_close;
	}
	strlcpy(adapter->name, name, sizeof(adapter->name));

	/* Turn echo off for better performance */
	taos->state = TAOS_STATE_EOFF;
	serio_write(serio, TAOS_CMD_ECHO_OFF);

	wait_event_interruptible_timeout(wq, taos->state == TAOS_STATE_IDLE,
	msecs_to_jiffies(250));
	if (taos->state != TAOS_STATE_IDLE) {
	err = -ENODEV;
	dev_err(&serio->dev, "TAOS EVM echo off failed "
	"(state=%d)\n", taos->state);
	goto exit_close;
	}

	err = i2c_add_adapter(adapter);
	if (err)
	goto exit_close;
	dev_info(&serio->dev, "Connected to TAOS EVM\n");

	taos->client = taos_instantiate_device(adapter);
	return 0;

	exit_close:
	serio_close(serio);
	exit_kfree:
	kfree(taos);
	exit:
	return err;
	}

	static void taos_disconnect(struct serio *serio)
	{
	struct taos_data *taos = serio_get_drvdata(serio);

	if (taos->client)
	i2c_unregister_device(taos->client);
	i2c_del_adapter(&taos->adapter);
	serio_close(serio);
	kfree(taos);

	dev_info(&serio->dev, "Disconnected from TAOS EVM\n");
	}

	static struct serio_device_id taos_serio_ids[] = {
	{
	.type = SERIO_RS232,
	.proto = SERIO_TAOSEVM,
	.id = SERIO_ANY,
	.extra = SERIO_ANY,
	},
	{ 0 }
	};
	MODULE_DEVICE_TABLE(serio, taos_serio_ids);

	static struct serio_driver taos_drv = {
	.driver = {
	.name = "taos-evm",
	},
	.description = "TAOS evaluation module driver",
	.id_table = taos_serio_ids,
	.connect = taos_connect,
	.disconnect = taos_disconnect,
	.interrupt = taos_interrupt,
	};

	static int __init taos_init(void)
	{
	return serio_register_driver(&taos_drv);
	}

	static void __exit taos_exit(void)
	{
	serio_unregister_driver(&taos_drv);
	}

	MODULE_AUTHOR("Jean Delvare <jdelvare@suse.de>");
	MODULE_DESCRIPTION("TAOS evaluation module driver");
	MODULE_LICENSE("GPL");

	module_init(taos_init);
	module_exit(taos_exit);