[mirror_ubuntu-jammy-kernel.git] / drivers / i2c / busses / i2c-diolan-u2c.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * 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)
 */

#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


/* 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 */
	int ep_in, ep_out;              /* Endpoints    */
	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, dev->ep_out),
			   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,
							      dev->ep_in),
					      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, dev->ep_in),
				   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;
		}
		ret = diolan_i2c_put_byte_ack(dev,
					      i2c_8bit_addr_from_msg(pmsg));
		if (ret < 0)
			goto abort;
		if (pmsg->flags & I2C_M_RD) {
			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 {
			for (j = 0; j < pmsg->len; j++) {
				ret = diolan_i2c_put_byte_ack(dev,
							      pmsg->buf[j]);
				if (ret < 0)
					goto abort;
			}
		}
	}
	ret = num;
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 usb_host_interface *hostif = interface->cur_altsetting;
	struct i2c_diolan_u2c *dev;
	int ret;

	if (hostif->desc.bInterfaceNumber != 0
	    || hostif->desc.bNumEndpoints < 2)
		return -ENODEV;

	/* allocate memory for our device state and initialize it */
	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
	if (dev == NULL) {
		ret = -ENOMEM;
		goto error;
	}
	dev->ep_out = hostif->endpoint[0].desc.bEndpointAddress;
	dev->ep_in = hostif->endpoint[1].desc.bEndpointAddress;

	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)
		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,
};

module_usb_driver(diolan_u2c_driver);

MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");
MODULE_DESCRIPTION(DRIVER_NAME " driver");
MODULE_LICENSE("GPL");
Commit	Line	Data
a10e763b	1	// SPDX-License-Identifier: GPL-2.0-only
335d7c58 GR	2	/*
	3	* Driver for the Diolan u2c-12 USB-I2C adapter
	4	*
	5	* Copyright (c) 2010-2011 Ericsson AB
	6	*
	7	* Derived from:
	8	* i2c-tiny-usb.c
	9	* Copyright (C) 2006-2007 Till Harbaum (Till@Harbaum.org)
335d7c58 GR	10	*/
	11
	12	#include <linux/kernel.h>
	13	#include <linux/errno.h>
	14	#include <linux/module.h>
	15	#include <linux/types.h>
	16	#include <linux/slab.h>
	17	#include <linux/usb.h>
	18	#include <linux/i2c.h>
	19
	20	#define DRIVER_NAME "i2c-diolan-u2c"
	21
	22	#define USB_VENDOR_ID_DIOLAN 0x0abf
	23	#define USB_DEVICE_ID_DIOLAN_U2C 0x3370
	24
335d7c58 GR	25
	26	/* commands via USB, must match command ids in the firmware */
	27	#define CMD_I2C_READ 0x01
	28	#define CMD_I2C_WRITE 0x02
	29	#define CMD_I2C_SCAN 0x03 /* Returns list of detected devices */
	30	#define CMD_I2C_RELEASE_SDA 0x04
	31	#define CMD_I2C_RELEASE_SCL 0x05
	32	#define CMD_I2C_DROP_SDA 0x06
	33	#define CMD_I2C_DROP_SCL 0x07
	34	#define CMD_I2C_READ_SDA 0x08
	35	#define CMD_I2C_READ_SCL 0x09
	36	#define CMD_GET_FW_VERSION 0x0a
	37	#define CMD_GET_SERIAL 0x0b
	38	#define CMD_I2C_START 0x0c
	39	#define CMD_I2C_STOP 0x0d
	40	#define CMD_I2C_REPEATED_START 0x0e
	41	#define CMD_I2C_PUT_BYTE 0x0f
	42	#define CMD_I2C_GET_BYTE 0x10
	43	#define CMD_I2C_PUT_ACK 0x11
	44	#define CMD_I2C_GET_ACK 0x12
	45	#define CMD_I2C_PUT_BYTE_ACK 0x13
	46	#define CMD_I2C_GET_BYTE_ACK 0x14
	47	#define CMD_I2C_SET_SPEED 0x1b
	48	#define CMD_I2C_GET_SPEED 0x1c
	49	#define CMD_I2C_SET_CLK_SYNC 0x24
	50	#define CMD_I2C_GET_CLK_SYNC 0x25
	51	#define CMD_I2C_SET_CLK_SYNC_TO 0x26
	52	#define CMD_I2C_GET_CLK_SYNC_TO 0x27
	53
	54	#define RESP_OK 0x00
	55	#define RESP_FAILED 0x01
	56	#define RESP_BAD_MEMADDR 0x04
	57	#define RESP_DATA_ERR 0x05
	58	#define RESP_NOT_IMPLEMENTED 0x06
	59	#define RESP_NACK 0x07
	60	#define RESP_TIMEOUT 0x09
	61
	62	#define U2C_I2C_SPEED_FAST 0 /* 400 kHz */
	63	#define U2C_I2C_SPEED_STD 1 /* 100 kHz */
	64	#define U2C_I2C_SPEED_2KHZ 242 /* 2 kHz, minimum speed */
	65	#define U2C_I2C_SPEED(f) ((DIV_ROUND_UP(1000000, (f)) - 10) / 2 + 1)
	66
	67	#define U2C_I2C_FREQ_FAST 400000
	68	#define U2C_I2C_FREQ_STD 100000
	69	#define U2C_I2C_FREQ(s) (1000000 / (2 * (s - 1) + 10))
	70
	71	#define DIOLAN_USB_TIMEOUT 100 /* in ms */
	72	#define DIOLAN_SYNC_TIMEOUT 20 /* in ms */
	73
	74	#define DIOLAN_OUTBUF_LEN 128
	75	#define DIOLAN_FLUSH_LEN (DIOLAN_OUTBUF_LEN - 4)
	76	#define DIOLAN_INBUF_LEN 256 /* Maximum supported receive length */
	77
	78	/* Structure to hold all of our device specific stuff */
	79	struct i2c_diolan_u2c {
	80	u8 obuffer[DIOLAN_OUTBUF_LEN]; /* output buffer */
	81	u8 ibuffer[DIOLAN_INBUF_LEN]; /* input buffer */
4e4844cc	82	int ep_in, ep_out; /* Endpoints */
335d7c58 GR	83	struct usb_device usb_dev; / the usb device for this device */
	84	struct usb_interface interface;/ the interface for this device */
	85	struct i2c_adapter adapter; /* i2c related things */
	86	int olen; /* Output buffer length */
	87	int ocount; /* Number of enqueued messages */
	88	};
	89
	90	static uint frequency = U2C_I2C_FREQ_STD; /* I2C clock frequency in Hz */
	91
	92	module_param(frequency, uint, S_IRUGO \| S_IWUSR);
	93	MODULE_PARM_DESC(frequency, "I2C clock frequency in hertz");
	94
	95	/* usb layer */
	96
	97	/* Send command to device, and get response. */
	98	static int diolan_usb_transfer(struct i2c_diolan_u2c *dev)
	99	{
	100	int ret = 0;
	101	int actual;
	102	int i;
	103
	104	if (!dev->olen \|\| !dev->ocount)
	105	return -EINVAL;
	106
	107	ret = usb_bulk_msg(dev->usb_dev,
4e4844cc	108	usb_sndbulkpipe(dev->usb_dev, dev->ep_out),
335d7c58 GR	109	dev->obuffer, dev->olen, &actual,
	110	DIOLAN_USB_TIMEOUT);
	111	if (!ret) {
	112	for (i = 0; i < dev->ocount; i++) {
	113	int tmpret;
	114
	115	tmpret = usb_bulk_msg(dev->usb_dev,
	116	usb_rcvbulkpipe(dev->usb_dev,
4e4844cc	117	dev->ep_in),
335d7c58 GR	118	dev->ibuffer,
	119	sizeof(dev->ibuffer), &actual,
	120	DIOLAN_USB_TIMEOUT);
	121	/*
	122	* Stop command processing if a previous command
	123	* returned an error.
	124	* Note that we still need to retrieve all messages.
	125	*/
	126	if (ret < 0)
	127	continue;
	128	ret = tmpret;
	129	if (ret == 0 && actual > 0) {
	130	switch (dev->ibuffer[actual - 1]) {
	131	case RESP_NACK:
	132	/*
	133	* Return ENXIO if NACK was received as
	134	* response to the address phase,
	135	* EIO otherwise
	136	*/
	137	ret = i == 1 ? -ENXIO : -EIO;
	138	break;
	139	case RESP_TIMEOUT:
	140	ret = -ETIMEDOUT;
	141	break;
	142	case RESP_OK:
	143	/* strip off return code */
	144	ret = actual - 1;
	145	break;
	146	default:
	147	ret = -EIO;
	148	break;
	149	}
	150	}
	151	}
	152	}
	153	dev->olen = 0;
	154	dev->ocount = 0;
	155	return ret;
	156	}
	157
	158	static int diolan_write_cmd(struct i2c_diolan_u2c *dev, bool flush)
	159	{
	160	if (flush \|\| dev->olen >= DIOLAN_FLUSH_LEN)
	161	return diolan_usb_transfer(dev);
	162	return 0;
	163	}
	164
	165	/* Send command (no data) */
	166	static int diolan_usb_cmd(struct i2c_diolan_u2c *dev, u8 command, bool flush)
	167	{
	168	dev->obuffer[dev->olen++] = command;
	169	dev->ocount++;
	170	return diolan_write_cmd(dev, flush);
	171	}
	172
	173	/* Send command with one byte of data */
	174	static int diolan_usb_cmd_data(struct i2c_diolan_u2c *dev, u8 command, u8 data,
	175	bool flush)
	176	{
	177	dev->obuffer[dev->olen++] = command;
	178	dev->obuffer[dev->olen++] = data;
	179	dev->ocount++;
	180	return diolan_write_cmd(dev, flush);
	181	}
182
183	/* Send command with two bytes of data */
184	static int diolan_usb_cmd_data2(struct i2c_diolan_u2c *dev, u8 command, u8 d1,
185	u8 d2, bool flush)
186	{
187	dev->obuffer[dev->olen++] = command;
188	dev->obuffer[dev->olen++] = d1;
189	dev->obuffer[dev->olen++] = d2;
190	dev->ocount++;
191	return diolan_write_cmd(dev, flush);
192	}
193
194	/*
195	* Flush input queue.
196	* If we don't do this at startup and the controller has queued up
197	* messages which were not retrieved, it will stop responding
198	* at some point.
199	*/
200	static void diolan_flush_input(struct i2c_diolan_u2c *dev)
201	{
202	int i;
203
204	for (i = 0; i < 10; i++) {
205	int actual = 0;
206	int ret;
207
208	ret = usb_bulk_msg(dev->usb_dev,
4e4844cc	209	usb_rcvbulkpipe(dev->usb_dev, dev->ep_in),
335d7c58 GR	210	dev->ibuffer, sizeof(dev->ibuffer), &actual,
	211	DIOLAN_USB_TIMEOUT);
	212	if (ret < 0 \|\| actual == 0)
	213	break;
	214	}
	215	if (i == 10)
	216	dev_err(&dev->interface->dev, "Failed to flush input buffer\n");
	217	}
	218
	219	static int diolan_i2c_start(struct i2c_diolan_u2c *dev)
	220	{
	221	return diolan_usb_cmd(dev, CMD_I2C_START, false);
	222	}
	223
	224	static int diolan_i2c_repeated_start(struct i2c_diolan_u2c *dev)
	225	{
	226	return diolan_usb_cmd(dev, CMD_I2C_REPEATED_START, false);
	227	}
	228
	229	static int diolan_i2c_stop(struct i2c_diolan_u2c *dev)
	230	{
	231	return diolan_usb_cmd(dev, CMD_I2C_STOP, true);
	232	}
	233
	234	static int diolan_i2c_get_byte_ack(struct i2c_diolan_u2c *dev, bool ack,
	235	u8 *byte)
	236	{
	237	int ret;
	238
	239	ret = diolan_usb_cmd_data(dev, CMD_I2C_GET_BYTE_ACK, ack, true);
	240	if (ret > 0)
	241	*byte = dev->ibuffer[0];
	242	else if (ret == 0)
	243	ret = -EIO;
	244
	245	return ret;
	246	}
	247
	248	static int diolan_i2c_put_byte_ack(struct i2c_diolan_u2c *dev, u8 byte)
	249	{
	250	return diolan_usb_cmd_data(dev, CMD_I2C_PUT_BYTE_ACK, byte, false);
	251	}
	252
	253	static int diolan_set_speed(struct i2c_diolan_u2c *dev, u8 speed)
	254	{
	255	return diolan_usb_cmd_data(dev, CMD_I2C_SET_SPEED, speed, true);
	256	}
	257
	258	/* Enable or disable clock synchronization (stretching) */
	259	static int diolan_set_clock_synch(struct i2c_diolan_u2c *dev, bool enable)
	260	{
	261	return diolan_usb_cmd_data(dev, CMD_I2C_SET_CLK_SYNC, enable, true);
	262	}
	263
	264	/* Set clock synchronization timeout in ms */
	265	static int diolan_set_clock_synch_timeout(struct i2c_diolan_u2c *dev, int ms)
	266	{
	267	int to_val = ms * 10;
	268
	269	return diolan_usb_cmd_data2(dev, CMD_I2C_SET_CLK_SYNC_TO,
	270	to_val & 0xff, (to_val >> 8) & 0xff, true);
	271	}
	272
	273	static void diolan_fw_version(struct i2c_diolan_u2c *dev)
274	{
275	int ret;
276
277	ret = diolan_usb_cmd(dev, CMD_GET_FW_VERSION, true);
278	if (ret >= 2)
279	dev_info(&dev->interface->dev,
280	"Diolan U2C firmware version %u.%u\n",
281	(unsigned int)dev->ibuffer[0],
282	(unsigned int)dev->ibuffer[1]);
283	}
284
285	static void diolan_get_serial(struct i2c_diolan_u2c *dev)
286	{
287	int ret;
288	u32 serial;
289
290	ret = diolan_usb_cmd(dev, CMD_GET_SERIAL, true);
291	if (ret >= 4) {
292	serial = le32_to_cpu((u32 )dev->ibuffer);
293	dev_info(&dev->interface->dev,
294	"Diolan U2C serial number %u\n", serial);
295	}
296	}
297
298	static int diolan_init(struct i2c_diolan_u2c *dev)
299	{
300	int speed, ret;
301
302	if (frequency >= 200000) {
303	speed = U2C_I2C_SPEED_FAST;
304	frequency = U2C_I2C_FREQ_FAST;
305	} else if (frequency >= 100000 \|\| frequency == 0) {
306	speed = U2C_I2C_SPEED_STD;
307	frequency = U2C_I2C_FREQ_STD;
308	} else {
309	speed = U2C_I2C_SPEED(frequency);
310	if (speed > U2C_I2C_SPEED_2KHZ)
311	speed = U2C_I2C_SPEED_2KHZ;
312	frequency = U2C_I2C_FREQ(speed);
313	}
314
315	dev_info(&dev->interface->dev,
316	"Diolan U2C at USB bus %03d address %03d speed %d Hz\n",
317	dev->usb_dev->bus->busnum, dev->usb_dev->devnum, frequency);
318
319	diolan_flush_input(dev);
320	diolan_fw_version(dev);
321	diolan_get_serial(dev);
322
323	/* Set I2C speed */
324	ret = diolan_set_speed(dev, speed);
325	if (ret < 0)
326	return ret;
327
328	/* Configure I2C clock synchronization */
329	ret = diolan_set_clock_synch(dev, speed != U2C_I2C_SPEED_FAST);
330	if (ret < 0)
331	return ret;
332
333	if (speed != U2C_I2C_SPEED_FAST)
334	ret = diolan_set_clock_synch_timeout(dev, DIOLAN_SYNC_TIMEOUT);
335
336	return ret;
337	}
338
339	/* i2c layer */
340
341	static int diolan_usb_xfer(struct i2c_adapter adapter, struct i2c_msg msgs,
342	int num)
343	{
344	struct i2c_diolan_u2c *dev = i2c_get_adapdata(adapter);
345	struct i2c_msg *pmsg;
346	int i, j;
347	int ret, sret;
348
349	ret = diolan_i2c_start(dev);
350	if (ret < 0)
351	return ret;
352
353	for (i = 0; i < num; i++) {
354	pmsg = &msgs[i];
355	if (i) {
356	ret = diolan_i2c_repeated_start(dev);
357	if (ret < 0)
358	goto abort;
359	}
30a64757 PR	360	ret = diolan_i2c_put_byte_ack(dev,
	361	i2c_8bit_addr_from_msg(pmsg));
	362	if (ret < 0)
	363	goto abort;
335d7c58	364	if (pmsg->flags & I2C_M_RD) {
335d7c58 GR	365	for (j = 0; j < pmsg->len; j++) {
	366	u8 byte;
	367	bool ack = j < pmsg->len - 1;
	368
	369	/*
	370	* Don't send NACK if this is the first byte
	371	* of a SMBUS_BLOCK message.
	372	*/
	373	if (j == 0 && (pmsg->flags & I2C_M_RECV_LEN))
	374	ack = true;
	375
	376	ret = diolan_i2c_get_byte_ack(dev, ack, &byte);
	377	if (ret < 0)
	378	goto abort;
	379	/*
	380	* Adjust count if first received byte is length
	381	*/
	382	if (j == 0 && (pmsg->flags & I2C_M_RECV_LEN)) {
	383	if (byte == 0
	384	\|\| byte > I2C_SMBUS_BLOCK_MAX) {
	385	ret = -EPROTO;
	386	goto abort;
	387	}
	388	pmsg->len += byte;
	389	}
	390	pmsg->buf[j] = byte;
	391	}
	392	} else {
335d7c58 GR	393	for (j = 0; j < pmsg->len; j++) {
	394	ret = diolan_i2c_put_byte_ack(dev,
	395	pmsg->buf[j]);
	396	if (ret < 0)
	397	goto abort;
	398	}
	399	}
	400	}
ab5625c3	401	ret = num;
335d7c58 GR	402	abort:
	403	sret = diolan_i2c_stop(dev);
	404	if (sret < 0 && ret >= 0)
	405	ret = sret;
	406	return ret;
	407	}
	408
	409	/*
	410	* Return list of supported functionality.
	411	*/
	412	static u32 diolan_usb_func(struct i2c_adapter *a)
	413	{
	414	return I2C_FUNC_I2C \| I2C_FUNC_SMBUS_EMUL \|
	415	I2C_FUNC_SMBUS_READ_BLOCK_DATA \| I2C_FUNC_SMBUS_BLOCK_PROC_CALL;
	416	}
	417
	418	static const struct i2c_algorithm diolan_usb_algorithm = {
	419	.master_xfer = diolan_usb_xfer,
	420	.functionality = diolan_usb_func,
	421	};
	422
	423	/* device layer */
	424
	425	static const struct usb_device_id diolan_u2c_table[] = {
	426	{ USB_DEVICE(USB_VENDOR_ID_DIOLAN, USB_DEVICE_ID_DIOLAN_U2C) },
	427	{ }
	428	};
	429
	430	MODULE_DEVICE_TABLE(usb, diolan_u2c_table);
	431
	432	static void diolan_u2c_free(struct i2c_diolan_u2c *dev)
	433	{
	434	usb_put_dev(dev->usb_dev);
	435	kfree(dev);
	436	}
	437
	438	static int diolan_u2c_probe(struct usb_interface *interface,
	439	const struct usb_device_id *id)
	440	{
4e4844cc	441	struct usb_host_interface *hostif = interface->cur_altsetting;
335d7c58 GR	442	struct i2c_diolan_u2c *dev;
	443	int ret;
	444
4e4844cc MV	445	if (hostif->desc.bInterfaceNumber != 0
	446	\|\| hostif->desc.bNumEndpoints < 2)
	447	return -ENODEV;
	448
335d7c58 GR	449	/* allocate memory for our device state and initialize it */
	450	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
	451	if (dev == NULL) {
335d7c58 GR	452	ret = -ENOMEM;
	453	goto error;
	454	}
4e4844cc MV	455	dev->ep_out = hostif->endpoint[0].desc.bEndpointAddress;
4e4844cc MV	456	dev->ep_in = hostif->endpoint[1].desc.bEndpointAddress;
335d7c58 GR	457
	458	dev->usb_dev = usb_get_dev(interface_to_usbdev(interface));
	459	dev->interface = interface;
	460
	461	/* save our data pointer in this interface device */
	462	usb_set_intfdata(interface, dev);
	463
	464	/* setup i2c adapter description */
	465	dev->adapter.owner = THIS_MODULE;
	466	dev->adapter.class = I2C_CLASS_HWMON;
	467	dev->adapter.algo = &diolan_usb_algorithm;
	468	i2c_set_adapdata(&dev->adapter, dev);
	469	snprintf(dev->adapter.name, sizeof(dev->adapter.name),
	470	DRIVER_NAME " at bus %03d device %03d",
	471	dev->usb_dev->bus->busnum, dev->usb_dev->devnum);
	472
	473	dev->adapter.dev.parent = &dev->interface->dev;
	474
	475	/* initialize diolan i2c interface */
	476	ret = diolan_init(dev);
	477	if (ret < 0) {
	478	dev_err(&interface->dev, "failed to initialize adapter\n");
	479	goto error_free;
	480	}
	481
	482	/* and finally attach to i2c layer */
	483	ret = i2c_add_adapter(&dev->adapter);
ea734404	484	if (ret < 0)
335d7c58	485	goto error_free;
335d7c58 GR	486
	487	dev_dbg(&interface->dev, "connected " DRIVER_NAME "\n");
	488
	489	return 0;
	490
	491	error_free:
	492	usb_set_intfdata(interface, NULL);
	493	diolan_u2c_free(dev);
	494	error:
	495	return ret;
	496	}
	497
	498	static void diolan_u2c_disconnect(struct usb_interface *interface)
	499	{
	500	struct i2c_diolan_u2c *dev = usb_get_intfdata(interface);
	501
	502	i2c_del_adapter(&dev->adapter);
	503	usb_set_intfdata(interface, NULL);
	504	diolan_u2c_free(dev);
	505
	506	dev_dbg(&interface->dev, "disconnected\n");
	507	}
	508
	509	static struct usb_driver diolan_u2c_driver = {
	510	.name = DRIVER_NAME,
	511	.probe = diolan_u2c_probe,
	512	.disconnect = diolan_u2c_disconnect,
	513	.id_table = diolan_u2c_table,
	514	};
	515
fe748483	516	module_usb_driver(diolan_u2c_driver);
335d7c58	517
83a638df	518	MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");
335d7c58 GR	519	MODULE_DESCRIPTION(DRIVER_NAME " driver");
335d7c58 GR	520	MODULE_LICENSE("GPL");