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Commit 335d7c58 authored by Guenter Roeck's avatar Guenter Roeck Committed by Ben Dooks
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i2c/busses: Add support for Diolan U2C-12 USB-I2C adapter 



This patch adds support for the Diolan U2C-12 USB-I2C adapter.
It also updates MAINTAINERS to list the author as maintainer.

Signed-off-by: default avatarGuenter Roeck <guenter.roeck@ericsson.com>
Signed-off-by: default avatarBen Dooks <ben-linux@fluff.org>
parent 6fb1b304

Documentation/i2c/busses/i2c-diolan-u2c

0 → 100644
+26 −0
Original line number Diff line number Diff line 
Kernel driver i2c-diolan-u2c



Supported adapters:

  * Diolan U2C-12 I2C-USB adapter

    Documentation:

	http://www.diolan.com/i2c/u2c12.html



Author: Guenter Roeck <guenter.roeck@ericsson.com>



Description

-----------



This is the driver for the Diolan U2C-12 USB-I2C adapter.



The Diolan U2C-12 I2C-USB Adapter provides a low cost solution to connect

a computer to I2C slave devices using a USB interface. It also supports

connectivity to SPI devices.



This driver only supports the I2C interface of U2C-12. The driver does not use

interrupts.





Module parameters

-----------------



* frequency: I2C bus frequency

MAINTAINERS

+6 −0
Original line number Diff line number Diff line
@@ -2093,6 +2093,12 @@ F: Documentation/serial/digiepca.txt 
F:	drivers/char/epca*

F:	drivers/char/digi*



DIOLAN U2C-12 I2C DRIVER

M:	Guenter Roeck <guenter.roeck@ericsson.com>

L:	linux-i2c@vger.kernel.org

S:	Maintained

F:	drivers/i2c/busses/i2c-diolan-u2c.c



DIRECTORY NOTIFICATION (DNOTIFY)

M:	Eric Paris <eparis@parisplace.org>

S:	Maintained

drivers/i2c/busses/Kconfig

+10 −0
Original line number Diff line number Diff line
@@ -648,6 +648,16 @@ config I2C_EG20T 


comment "External I2C/SMBus adapter drivers"



config I2C_DIOLAN_U2C

	tristate "Diolan U2C-12 USB adapter"

	depends on USB

	help

	  If you say yes to this option, support will be included for Diolan

	  U2C-12, a USB to I2C interface.



	  This driver can also be built as a module.  If so, the module

	  will be called i2c-diolan-u2c.



config I2C_PARPORT

	tristate "Parallel port adapter"

	depends on PARPORT

drivers/i2c/busses/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -64,6 +64,7 @@ obj-$(CONFIG_I2C_XILINX) += i2c-xiic.o 
obj-$(CONFIG_I2C_EG20T)         += i2c-eg20t.o



# External I2C/SMBus adapter drivers

obj-$(CONFIG_I2C_DIOLAN_U2C)	+= i2c-diolan-u2c.o

obj-$(CONFIG_I2C_PARPORT)	+= i2c-parport.o

obj-$(CONFIG_I2C_PARPORT_LIGHT)	+= i2c-parport-light.o

obj-$(CONFIG_I2C_TAOS_EVM)	+= i2c-taos-evm.o

drivers/i2c/busses/i2c-diolan-u2c.c

0 → 100644
+535 −0
Original line number Diff line number Diff line 
/*

 * Driver for the Diolan u2c-12 USB-I2C adapter

 *

 * Copyright (c) 2010-2011 Ericsson AB

 *

 * Derived from:

 *  i2c-tiny-usb.c

 *  Copyright (C) 2006-2007 Till Harbaum (Till@Harbaum.org)

 *

 * 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.

 */



#include <linux/kernel.h>

#include <linux/errno.h>

#include <linux/module.h>

#include <linux/types.h>

#include <linux/slab.h>

#include <linux/usb.h>

#include <linux/i2c.h>



#define DRIVER_NAME		"i2c-diolan-u2c"



#define USB_VENDOR_ID_DIOLAN		0x0abf

#define USB_DEVICE_ID_DIOLAN_U2C	0x3370



#define DIOLAN_OUT_EP		0x02

#define DIOLAN_IN_EP		0x84



/* commands via USB, must match command ids in the firmware */

#define CMD_I2C_READ		0x01

#define CMD_I2C_WRITE		0x02

#define CMD_I2C_SCAN		0x03	/* Returns list of detected devices */

#define CMD_I2C_RELEASE_SDA	0x04

#define CMD_I2C_RELEASE_SCL	0x05

#define CMD_I2C_DROP_SDA	0x06

#define CMD_I2C_DROP_SCL	0x07

#define CMD_I2C_READ_SDA	0x08

#define CMD_I2C_READ_SCL	0x09

#define CMD_GET_FW_VERSION	0x0a

#define CMD_GET_SERIAL		0x0b

#define CMD_I2C_START		0x0c

#define CMD_I2C_STOP		0x0d

#define CMD_I2C_REPEATED_START	0x0e

#define CMD_I2C_PUT_BYTE	0x0f

#define CMD_I2C_GET_BYTE	0x10

#define CMD_I2C_PUT_ACK		0x11

#define CMD_I2C_GET_ACK		0x12

#define CMD_I2C_PUT_BYTE_ACK	0x13

#define CMD_I2C_GET_BYTE_ACK	0x14

#define CMD_I2C_SET_SPEED	0x1b

#define CMD_I2C_GET_SPEED	0x1c

#define CMD_I2C_SET_CLK_SYNC	0x24

#define CMD_I2C_GET_CLK_SYNC	0x25

#define CMD_I2C_SET_CLK_SYNC_TO	0x26

#define CMD_I2C_GET_CLK_SYNC_TO	0x27



#define RESP_OK			0x00

#define RESP_FAILED		0x01

#define RESP_BAD_MEMADDR	0x04

#define RESP_DATA_ERR		0x05

#define RESP_NOT_IMPLEMENTED	0x06

#define RESP_NACK		0x07

#define RESP_TIMEOUT		0x09



#define U2C_I2C_SPEED_FAST	0	/* 400 kHz */

#define U2C_I2C_SPEED_STD	1	/* 100 kHz */

#define U2C_I2C_SPEED_2KHZ	242	/* 2 kHz, minimum speed */

#define U2C_I2C_SPEED(f)	((DIV_ROUND_UP(1000000, (f)) - 10) / 2 + 1)



#define U2C_I2C_FREQ_FAST	400000

#define U2C_I2C_FREQ_STD	100000

#define U2C_I2C_FREQ(s)		(1000000 / (2 * (s - 1) + 10))



#define DIOLAN_USB_TIMEOUT	100	/* in ms */

#define DIOLAN_SYNC_TIMEOUT	20	/* in ms */



#define DIOLAN_OUTBUF_LEN	128

#define DIOLAN_FLUSH_LEN	(DIOLAN_OUTBUF_LEN - 4)

#define DIOLAN_INBUF_LEN	256	/* Maximum supported receive length */



/* Structure to hold all of our device specific stuff */

struct i2c_diolan_u2c {

	u8 obuffer[DIOLAN_OUTBUF_LEN];	/* output buffer */

	u8 ibuffer[DIOLAN_INBUF_LEN];	/* input buffer */

	struct usb_device *usb_dev;	/* the usb device for this device */

	struct usb_interface *interface;/* the interface for this device */

	struct i2c_adapter adapter;	/* i2c related things */

	int olen;			/* Output buffer length */

	int ocount;			/* Number of enqueued messages */

};



static uint frequency = U2C_I2C_FREQ_STD;	/* I2C clock frequency in Hz */



module_param(frequency, uint, S_IRUGO | S_IWUSR);

MODULE_PARM_DESC(frequency, "I2C clock frequency in hertz");



/* usb layer */



/* Send command to device, and get response. */

static int diolan_usb_transfer(struct i2c_diolan_u2c *dev)

{

	int ret = 0;

	int actual;

	int i;



	if (!dev->olen || !dev->ocount)

		return -EINVAL;



	ret = usb_bulk_msg(dev->usb_dev,

			   usb_sndbulkpipe(dev->usb_dev, DIOLAN_OUT_EP),

			   dev->obuffer, dev->olen, &actual,

			   DIOLAN_USB_TIMEOUT);

	if (!ret) {

		for (i = 0; i < dev->ocount; i++) {

			int tmpret;



			tmpret = usb_bulk_msg(dev->usb_dev,

					      usb_rcvbulkpipe(dev->usb_dev,

							      DIOLAN_IN_EP),

					      dev->ibuffer,

					      sizeof(dev->ibuffer), &actual,

					      DIOLAN_USB_TIMEOUT);

			/*

			 * Stop command processing if a previous command

			 * returned an error.

			 * Note that we still need to retrieve all messages.

			 */

			if (ret < 0)

				continue;

			ret = tmpret;

			if (ret == 0 && actual > 0) {

				switch (dev->ibuffer[actual - 1]) {

				case RESP_NACK:

					/*

					 * Return ENXIO if NACK was received as

					 * response to the address phase,

					 * EIO otherwise

					 */

					ret = i == 1 ? -ENXIO : -EIO;

					break;

				case RESP_TIMEOUT:

					ret = -ETIMEDOUT;

					break;

				case RESP_OK:

					/* strip off return code */

					ret = actual - 1;

					break;

				default:

					ret = -EIO;

					break;

				}

			}

		}

	}

	dev->olen = 0;

	dev->ocount = 0;

	return ret;

}



static int diolan_write_cmd(struct i2c_diolan_u2c *dev, bool flush)

{

	if (flush || dev->olen >= DIOLAN_FLUSH_LEN)

		return diolan_usb_transfer(dev);

	return 0;

}



/* Send command (no data) */

static int diolan_usb_cmd(struct i2c_diolan_u2c *dev, u8 command, bool flush)

{

	dev->obuffer[dev->olen++] = command;

	dev->ocount++;

	return diolan_write_cmd(dev, flush);

}



/* Send command with one byte of data */

static int diolan_usb_cmd_data(struct i2c_diolan_u2c *dev, u8 command, u8 data,

			       bool flush)

{

	dev->obuffer[dev->olen++] = command;

	dev->obuffer[dev->olen++] = data;

	dev->ocount++;

	return diolan_write_cmd(dev, flush);

}



/* Send command with two bytes of data */

static int diolan_usb_cmd_data2(struct i2c_diolan_u2c *dev, u8 command, u8 d1,

				u8 d2, bool flush)

{

	dev->obuffer[dev->olen++] = command;

	dev->obuffer[dev->olen++] = d1;

	dev->obuffer[dev->olen++] = d2;

	dev->ocount++;

	return diolan_write_cmd(dev, flush);

}



/*

 * Flush input queue.

 * If we don't do this at startup and the controller has queued up

 * messages which were not retrieved, it will stop responding

 * at some point.

 */

static void diolan_flush_input(struct i2c_diolan_u2c *dev)

{

	int i;



	for (i = 0; i < 10; i++) {

		int actual = 0;

		int ret;



		ret = usb_bulk_msg(dev->usb_dev,

				   usb_rcvbulkpipe(dev->usb_dev, DIOLAN_IN_EP),

				   dev->ibuffer, sizeof(dev->ibuffer), &actual,

				   DIOLAN_USB_TIMEOUT);

		if (ret < 0 || actual == 0)

			break;

	}

	if (i == 10)

		dev_err(&dev->interface->dev, "Failed to flush input buffer\n");

}



static int diolan_i2c_start(struct i2c_diolan_u2c *dev)

{

	return diolan_usb_cmd(dev, CMD_I2C_START, false);

}



static int diolan_i2c_repeated_start(struct i2c_diolan_u2c *dev)

{

	return diolan_usb_cmd(dev, CMD_I2C_REPEATED_START, false);

}



static int diolan_i2c_stop(struct i2c_diolan_u2c *dev)

{

	return diolan_usb_cmd(dev, CMD_I2C_STOP, true);

}



static int diolan_i2c_get_byte_ack(struct i2c_diolan_u2c *dev, bool ack,

				   u8 *byte)

{

	int ret;



	ret = diolan_usb_cmd_data(dev, CMD_I2C_GET_BYTE_ACK, ack, true);

	if (ret > 0)

		*byte = dev->ibuffer[0];

	else if (ret == 0)

		ret = -EIO;



	return ret;

}



static int diolan_i2c_put_byte_ack(struct i2c_diolan_u2c *dev, u8 byte)

{

	return diolan_usb_cmd_data(dev, CMD_I2C_PUT_BYTE_ACK, byte, false);

}



static int diolan_set_speed(struct i2c_diolan_u2c *dev, u8 speed)

{

	return diolan_usb_cmd_data(dev, CMD_I2C_SET_SPEED, speed, true);

}



/* Enable or disable clock synchronization (stretching) */

static int diolan_set_clock_synch(struct i2c_diolan_u2c *dev, bool enable)

{

	return diolan_usb_cmd_data(dev, CMD_I2C_SET_CLK_SYNC, enable, true);

}



/* Set clock synchronization timeout in ms */

static int diolan_set_clock_synch_timeout(struct i2c_diolan_u2c *dev, int ms)

{

	int to_val = ms * 10;



	return diolan_usb_cmd_data2(dev, CMD_I2C_SET_CLK_SYNC_TO,

				    to_val & 0xff, (to_val >> 8) & 0xff, true);

}



static void diolan_fw_version(struct i2c_diolan_u2c *dev)

{

	int ret;



	ret = diolan_usb_cmd(dev, CMD_GET_FW_VERSION, true);

	if (ret >= 2)

		dev_info(&dev->interface->dev,

			 "Diolan U2C firmware version %u.%u\n",

			 (unsigned int)dev->ibuffer[0],

			 (unsigned int)dev->ibuffer[1]);

}



static void diolan_get_serial(struct i2c_diolan_u2c *dev)

{

	int ret;

	u32 serial;



	ret = diolan_usb_cmd(dev, CMD_GET_SERIAL, true);

	if (ret >= 4) {

		serial = le32_to_cpu(*(u32 *)dev->ibuffer);

		dev_info(&dev->interface->dev,

			 "Diolan U2C serial number %u\n", serial);

	}

}



static int diolan_init(struct i2c_diolan_u2c *dev)

{

	int speed, ret;



	if (frequency >= 200000) {

		speed = U2C_I2C_SPEED_FAST;

		frequency = U2C_I2C_FREQ_FAST;

	} else if (frequency >= 100000 || frequency == 0) {

		speed = U2C_I2C_SPEED_STD;

		frequency = U2C_I2C_FREQ_STD;

	} else {

		speed = U2C_I2C_SPEED(frequency);

		if (speed > U2C_I2C_SPEED_2KHZ)

			speed = U2C_I2C_SPEED_2KHZ;

		frequency = U2C_I2C_FREQ(speed);

	}



	dev_info(&dev->interface->dev,

		 "Diolan U2C at USB bus %03d address %03d speed %d Hz\n",

		 dev->usb_dev->bus->busnum, dev->usb_dev->devnum, frequency);



	diolan_flush_input(dev);

	diolan_fw_version(dev);

	diolan_get_serial(dev);



	/* Set I2C speed */

	ret = diolan_set_speed(dev, speed);

	if (ret < 0)

		return ret;



	/* Configure I2C clock synchronization */

	ret = diolan_set_clock_synch(dev, speed != U2C_I2C_SPEED_FAST);

	if (ret < 0)

		return ret;



	if (speed != U2C_I2C_SPEED_FAST)

		ret = diolan_set_clock_synch_timeout(dev, DIOLAN_SYNC_TIMEOUT);



	return ret;

}



/* i2c layer */



static int diolan_usb_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs,

			   int num)

{

	struct i2c_diolan_u2c *dev = i2c_get_adapdata(adapter);

	struct i2c_msg *pmsg;

	int i, j;

	int ret, sret;



	ret = diolan_i2c_start(dev);

	if (ret < 0)

		return ret;



	for (i = 0; i < num; i++) {

		pmsg = &msgs[i];

		if (i) {

			ret = diolan_i2c_repeated_start(dev);

			if (ret < 0)

				goto abort;

		}

		if (pmsg->flags & I2C_M_RD) {

			ret =

			    diolan_i2c_put_byte_ack(dev, (pmsg->addr << 1) | 1);

			if (ret < 0)

				goto abort;

			for (j = 0; j < pmsg->len; j++) {

				u8 byte;

				bool ack = j < pmsg->len - 1;



				/*

				 * Don't send NACK if this is the first byte

				 * of a SMBUS_BLOCK message.

				 */

				if (j == 0 && (pmsg->flags & I2C_M_RECV_LEN))

					ack = true;



				ret = diolan_i2c_get_byte_ack(dev, ack, &byte);

				if (ret < 0)

					goto abort;

				/*

				 * Adjust count if first received byte is length

				 */

				if (j == 0 && (pmsg->flags & I2C_M_RECV_LEN)) {

					if (byte == 0

					    || byte > I2C_SMBUS_BLOCK_MAX) {

						ret = -EPROTO;

						goto abort;

					}

					pmsg->len += byte;

				}

				pmsg->buf[j] = byte;

			}

		} else {

			ret = diolan_i2c_put_byte_ack(dev, pmsg->addr << 1);

			if (ret < 0)

				goto abort;

			for (j = 0; j < pmsg->len; j++) {

				ret = diolan_i2c_put_byte_ack(dev,

							      pmsg->buf[j]);

				if (ret < 0)

					goto abort;

			}

		}

	}

abort:

	sret = diolan_i2c_stop(dev);

	if (sret < 0 && ret >= 0)

		ret = sret;

	return ret;

}



/*

 * Return list of supported functionality.

 */

static u32 diolan_usb_func(struct i2c_adapter *a)

{

	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |

	       I2C_FUNC_SMBUS_READ_BLOCK_DATA | I2C_FUNC_SMBUS_BLOCK_PROC_CALL;

}



static const struct i2c_algorithm diolan_usb_algorithm = {

	.master_xfer = diolan_usb_xfer,

	.functionality = diolan_usb_func,

};



/* device layer */



static const struct usb_device_id diolan_u2c_table[] = {

	{ USB_DEVICE(USB_VENDOR_ID_DIOLAN, USB_DEVICE_ID_DIOLAN_U2C) },

	{ }

};



MODULE_DEVICE_TABLE(usb, diolan_u2c_table);



static void diolan_u2c_free(struct i2c_diolan_u2c *dev)

{

	usb_put_dev(dev->usb_dev);

	kfree(dev);

}



static int diolan_u2c_probe(struct usb_interface *interface,

			    const struct usb_device_id *id)

{

	struct i2c_diolan_u2c *dev;

	int ret;



	/* allocate memory for our device state and initialize it */

	dev = kzalloc(sizeof(*dev), GFP_KERNEL);

	if (dev == NULL) {

		dev_err(&interface->dev, "no memory for device state\n");

		ret = -ENOMEM;

		goto error;

	}



	dev->usb_dev = usb_get_dev(interface_to_usbdev(interface));

	dev->interface = interface;



	/* save our data pointer in this interface device */

	usb_set_intfdata(interface, dev);



	/* setup i2c adapter description */

	dev->adapter.owner = THIS_MODULE;

	dev->adapter.class = I2C_CLASS_HWMON;

	dev->adapter.algo = &diolan_usb_algorithm;

	i2c_set_adapdata(&dev->adapter, dev);

	snprintf(dev->adapter.name, sizeof(dev->adapter.name),

		 DRIVER_NAME " at bus %03d device %03d",

		 dev->usb_dev->bus->busnum, dev->usb_dev->devnum);



	dev->adapter.dev.parent = &dev->interface->dev;



	/* initialize diolan i2c interface */

	ret = diolan_init(dev);

	if (ret < 0) {

		dev_err(&interface->dev, "failed to initialize adapter\n");

		goto error_free;

	}



	/* and finally attach to i2c layer */

	ret = i2c_add_adapter(&dev->adapter);

	if (ret < 0) {

		dev_err(&interface->dev, "failed to add I2C adapter\n");

		goto error_free;

	}



	dev_dbg(&interface->dev, "connected " DRIVER_NAME "\n");



	return 0;



error_free:

	usb_set_intfdata(interface, NULL);

	diolan_u2c_free(dev);

error:

	return ret;

}



static void diolan_u2c_disconnect(struct usb_interface *interface)

{

	struct i2c_diolan_u2c *dev = usb_get_intfdata(interface);



	i2c_del_adapter(&dev->adapter);

	usb_set_intfdata(interface, NULL);

	diolan_u2c_free(dev);



	dev_dbg(&interface->dev, "disconnected\n");

}



static struct usb_driver diolan_u2c_driver = {

	.name = DRIVER_NAME,

	.probe = diolan_u2c_probe,

	.disconnect = diolan_u2c_disconnect,

	.id_table = diolan_u2c_table,

};



static int __init diolan_u2c_init(void)

{

	/* register this driver with the USB subsystem */

	return usb_register(&diolan_u2c_driver);

}



static void __exit diolan_u2c_exit(void)

{

	/* deregister this driver with the USB subsystem */

	usb_deregister(&diolan_u2c_driver);

}



module_init(diolan_u2c_init);

module_exit(diolan_u2c_exit);



MODULE_AUTHOR("Guenter Roeck <guenter.roeck@ericsson.com>");

MODULE_DESCRIPTION(DRIVER_NAME " driver");

MODULE_LICENSE("GPL");