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Commit 174a13aa authored by Lars Poeschel's avatar Lars Poeschel Committed by Samuel Ortiz
Browse files

i2c: Add viperboard i2c master driver 



This adds the mfd cell to use the i2c part of the Nano River Technologies
viperboard as i2c master.

Signed-off-by: default avatarLars Poeschel <poeschel@lemonage.de>
Signed-off-by: default avatarSamuel Ortiz <sameo@linux.intel.com>
parent 9d5b72de

drivers/i2c/busses/Kconfig

+10 −0
Original line number Diff line number Diff line
@@ -818,6 +818,16 @@ config I2C_TINY_USB 
	  This driver can also be built as a module.  If so, the module

	  will be called i2c-tiny-usb.



config I2C_VIPERBOARD

	tristate "Viperboard I2C master support"

	depends on MFD_VIPERBOARD && USB

	help

	  Say yes here to access the I2C part of the Nano River

	  Technologies Viperboard as I2C master.

          See viperboard API specification and Nano

          River Tech's viperboard.h for detailed meaning

          of the module parameters.



comment "Other I2C/SMBus bus drivers"



config I2C_ACORN

drivers/i2c/busses/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -79,6 +79,7 @@ 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

obj-$(CONFIG_I2C_TINY_USB)	+= i2c-tiny-usb.o

obj-$(CONFIG_I2C_VIPERBOARD)	+= i2c-viperboard.o



# Other I2C/SMBus bus drivers

obj-$(CONFIG_I2C_ACORN)		+= i2c-acorn.o

drivers/i2c/busses/i2c-viperboard.c

0 → 100644
+480 −0
Original line number Diff line number Diff line 
/*

 *  Nano River Technologies viperboard i2c master driver

 *

 *  (C) 2012 by Lemonage GmbH

 *  Author: Lars Poeschel <poeschel@lemonage.de>

 *  All rights reserved.

 *

 *  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.

 *

 */



#include <linux/kernel.h>

#include <linux/errno.h>

#include <linux/module.h>

#include <linux/slab.h>

#include <linux/types.h>

#include <linux/mutex.h>

#include <linux/platform_device.h>



#include <linux/usb.h>

#include <linux/i2c.h>



#include <linux/mfd/viperboard.h>



struct vprbrd_i2c {

	struct i2c_adapter i2c;

	u8 bus_freq_param;

};



/* i2c bus frequency module parameter */

static u8 i2c_bus_param;

static unsigned int i2c_bus_freq = 100;

module_param(i2c_bus_freq, int, 0);

MODULE_PARM_DESC(i2c_bus_freq,

	"i2c bus frequency in khz (default is 100) valid values: 10, 100, 200, 400, 1000, 3000, 6000");



static int vprbrd_i2c_status(struct i2c_adapter *i2c,

	struct vprbrd_i2c_status *status, bool prev_error)

{

	u16 bytes_xfer;

	int ret;

	struct vprbrd *vb = (struct vprbrd *)i2c->algo_data;



	/* check for protocol error */

	bytes_xfer = sizeof(struct vprbrd_i2c_status);



	ret = usb_control_msg(vb->usb_dev, usb_rcvctrlpipe(vb->usb_dev, 0),

		VPRBRD_USB_REQUEST_I2C, VPRBRD_USB_TYPE_IN, 0x0000, 0x0000,

		status, bytes_xfer, VPRBRD_USB_TIMEOUT_MS);



	if (ret != bytes_xfer)

		prev_error = true;



	if (prev_error) {

		dev_err(&i2c->dev, "failure in usb communication\n");

		return -EREMOTEIO;

	}



	dev_dbg(&i2c->dev, "  status = %d\n", status->status);

	if (status->status != 0x00) {

		dev_err(&i2c->dev, "failure: i2c protocol error\n");

		return -EPROTO;

	}

	return 0;

}



static int vprbrd_i2c_receive(struct usb_device *usb_dev,

	struct vprbrd_i2c_read_msg *rmsg, int bytes_xfer)

{

	int ret, bytes_actual;

	int error = 0;



	/* send the read request */

	ret = usb_bulk_msg(usb_dev,

		usb_sndbulkpipe(usb_dev, VPRBRD_EP_OUT), rmsg,

		sizeof(struct vprbrd_i2c_read_hdr), &bytes_actual,

		VPRBRD_USB_TIMEOUT_MS);



	if ((ret < 0)

		|| (bytes_actual != sizeof(struct vprbrd_i2c_read_hdr))) {

		dev_err(&usb_dev->dev, "failure transmitting usb\n");

		error = -EREMOTEIO;

	}



	/* read the actual data */

	ret = usb_bulk_msg(usb_dev,

		usb_rcvbulkpipe(usb_dev, VPRBRD_EP_IN), rmsg,

		bytes_xfer, &bytes_actual, VPRBRD_USB_TIMEOUT_MS);



	if ((ret < 0) || (bytes_xfer != bytes_actual)) {

		dev_err(&usb_dev->dev, "failure receiving usb\n");

		error = -EREMOTEIO;

	}

	return error;

}



static int vprbrd_i2c_addr(struct usb_device *usb_dev,

	struct vprbrd_i2c_addr_msg *amsg)

{

	int ret, bytes_actual;



	ret = usb_bulk_msg(usb_dev,

		usb_sndbulkpipe(usb_dev, VPRBRD_EP_OUT), amsg,

		sizeof(struct vprbrd_i2c_addr_msg), &bytes_actual,

		VPRBRD_USB_TIMEOUT_MS);



	if ((ret < 0) ||

			(sizeof(struct vprbrd_i2c_addr_msg) != bytes_actual)) {

		dev_err(&usb_dev->dev, "failure transmitting usb\n");

		return -EREMOTEIO;

	}

	return 0;

}



static int vprbrd_i2c_read(struct vprbrd *vb, struct i2c_msg *msg)

{

	int ret;

	u16 remain_len, bytes_xfer, len1, len2,

		start = 0x0000;

	struct vprbrd_i2c_read_msg *rmsg =

		(struct vprbrd_i2c_read_msg *)vb->buf;



	remain_len = msg->len;

	rmsg->header.cmd = VPRBRD_I2C_CMD_READ;

	while (remain_len > 0) {

		rmsg->header.addr = cpu_to_le16(start + 0x4000);

		if (remain_len <= 255) {

			len1 = remain_len;

			len2 = 0x00;

			rmsg->header.len0 = remain_len;

			rmsg->header.len1 = 0x00;

			rmsg->header.len2 = 0x00;

			rmsg->header.len3 = 0x00;

			rmsg->header.len4 = 0x00;

			rmsg->header.len5 = 0x00;

			remain_len = 0;

		} else if (remain_len <= 510) {

			len1 = remain_len;

			len2 = 0x00;

			rmsg->header.len0 = remain_len - 255;

			rmsg->header.len1 = 0xff;

			rmsg->header.len2 = 0x00;

			rmsg->header.len3 = 0x00;

			rmsg->header.len4 = 0x00;

			rmsg->header.len5 = 0x00;

			remain_len = 0;

		} else if (remain_len <= 512) {

			len1 = remain_len;

			len2 = 0x00;

			rmsg->header.len0 = remain_len - 510;

			rmsg->header.len1 = 0xff;

			rmsg->header.len2 = 0xff;

			rmsg->header.len3 = 0x00;

			rmsg->header.len4 = 0x00;

			rmsg->header.len5 = 0x00;

			remain_len = 0;

		} else if (remain_len <= 767) {

			len1 = 512;

			len2 = remain_len - 512;

			rmsg->header.len0 = 0x02;

			rmsg->header.len1 = 0xff;

			rmsg->header.len2 = 0xff;

			rmsg->header.len3 = remain_len - 512;

			rmsg->header.len4 = 0x00;

			rmsg->header.len5 = 0x00;

			bytes_xfer = remain_len;

			remain_len = 0;

		} else if (remain_len <= 1022) {

			len1 = 512;

			len2 = remain_len - 512;

			rmsg->header.len0 = 0x02;

			rmsg->header.len1 = 0xff;

			rmsg->header.len2 = 0xff;

			rmsg->header.len3 = remain_len - 767;

			rmsg->header.len4 = 0xff;

			rmsg->header.len5 = 0x00;

			remain_len = 0;

		} else if (remain_len <= 1024) {

			len1 = 512;

			len2 = remain_len - 512;

			rmsg->header.len0 = 0x02;

			rmsg->header.len1 = 0xff;

			rmsg->header.len2 = 0xff;

			rmsg->header.len3 = remain_len - 1022;

			rmsg->header.len4 = 0xff;

			rmsg->header.len5 = 0xff;

			remain_len = 0;

		} else {

			len1 = 512;

			len2 = 512;

			rmsg->header.len0 = 0x02;

			rmsg->header.len1 = 0xff;

			rmsg->header.len2 = 0xff;

			rmsg->header.len3 = 0x02;

			rmsg->header.len4 = 0xff;

			rmsg->header.len5 = 0xff;

			remain_len -= 1024;

			start += 1024;

		}

		rmsg->header.tf1 = cpu_to_le16(len1);

		rmsg->header.tf2 = cpu_to_le16(len2);



		/* first read transfer */

		ret = vprbrd_i2c_receive(vb->usb_dev, rmsg, len1);

		if (ret < 0)

			return ret;

		/* copy the received data */

		memcpy(msg->buf + start, rmsg, len1);



		/* second read transfer if neccessary */

		if (len2 > 0) {

			ret = vprbrd_i2c_receive(vb->usb_dev, rmsg, len2);

			if (ret < 0)

				return ret;

			/* copy the received data */

			memcpy(msg->buf + start + 512, rmsg, len2);

		}

	}

	return 0;

}



static int vprbrd_i2c_write(struct vprbrd *vb, struct i2c_msg *msg)

{

	int ret, bytes_actual;

	u16 remain_len, bytes_xfer,

		start = 0x0000;

	struct vprbrd_i2c_write_msg *wmsg =

		(struct vprbrd_i2c_write_msg *)vb->buf;



	remain_len = msg->len;

	wmsg->header.cmd = VPRBRD_I2C_CMD_WRITE;

	wmsg->header.last = 0x00;

	wmsg->header.chan = 0x00;

	wmsg->header.spi = 0x0000;

	while (remain_len > 0) {

		wmsg->header.addr = cpu_to_le16(start + 0x4000);

		if (remain_len > 503) {

			wmsg->header.len1 = 0xff;

			wmsg->header.len2 = 0xf8;

			remain_len -= 503;

			bytes_xfer = 503 + sizeof(struct vprbrd_i2c_write_hdr);

			start += 503;

		} else if (remain_len > 255) {

			wmsg->header.len1 = 0xff;

			wmsg->header.len2 = (remain_len - 255);

			bytes_xfer = remain_len +

				sizeof(struct vprbrd_i2c_write_hdr);

			remain_len = 0;

		} else {

			wmsg->header.len1 = remain_len;

			wmsg->header.len2 = 0x00;

			bytes_xfer = remain_len +

				sizeof(struct vprbrd_i2c_write_hdr);

			remain_len = 0;

		}

		memcpy(wmsg->data, msg->buf + start,

			bytes_xfer - sizeof(struct vprbrd_i2c_write_hdr));



		ret = usb_bulk_msg(vb->usb_dev,

			usb_sndbulkpipe(vb->usb_dev,

			VPRBRD_EP_OUT), wmsg,

			bytes_xfer, &bytes_actual, VPRBRD_USB_TIMEOUT_MS);

		if ((ret < 0) || (bytes_xfer != bytes_actual))

			return -EREMOTEIO;

	}

	return 0;

}



static int vprbrd_i2c_xfer(struct i2c_adapter *i2c, struct i2c_msg *msgs,

		int num)

{

	struct i2c_msg *pmsg;

	int i, ret,

		error = 0;

	struct vprbrd *vb = (struct vprbrd *)i2c->algo_data;

	struct vprbrd_i2c_addr_msg *amsg =

		(struct vprbrd_i2c_addr_msg *)vb->buf;

	struct vprbrd_i2c_status *smsg = (struct vprbrd_i2c_status *)vb->buf;



	dev_dbg(&i2c->dev, "master xfer %d messages:\n", num);



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

		pmsg = &msgs[i];



		dev_dbg(&i2c->dev,

			"  %d: %s (flags %d) %d bytes to 0x%02x\n",

			i, pmsg->flags & I2C_M_RD ? "read" : "write",

			pmsg->flags, pmsg->len, pmsg->addr);



		/* msgs longer than 2048 bytes are not supported by adapter */

		if (pmsg->len > 2048)

			return -EINVAL;



		mutex_lock(&vb->lock);

		/* directly send the message */

		if (pmsg->flags & I2C_M_RD) {

			/* read data */

			amsg->cmd = VPRBRD_I2C_CMD_ADDR;

			amsg->unknown2 = 0x00;

			amsg->unknown3 = 0x00;

			amsg->addr = pmsg->addr;

			amsg->unknown1 = 0x01;

			amsg->len = cpu_to_le16(pmsg->len);

			/* send the addr and len, we're interested to board */

			ret = vprbrd_i2c_addr(vb->usb_dev, amsg);

			if (ret < 0)

				error = ret;



			ret = vprbrd_i2c_read(vb, pmsg);

			if (ret < 0)

				error = ret;



			ret = vprbrd_i2c_status(i2c, smsg, error);

			if (ret < 0)

				error = ret;

			/* in case of protocol error, return the error */

			if (error < 0)

				goto error;

		} else {

			/* write data */

			ret = vprbrd_i2c_write(vb, pmsg);



			amsg->cmd = VPRBRD_I2C_CMD_ADDR;

			amsg->unknown2 = 0x00;

			amsg->unknown3 = 0x00;

			amsg->addr = pmsg->addr;

			amsg->unknown1 = 0x00;

			amsg->len = cpu_to_le16(pmsg->len);

			/* send the addr, the data goes to to board */

			ret = vprbrd_i2c_addr(vb->usb_dev, amsg);

			if (ret < 0)

				error = ret;



			ret = vprbrd_i2c_status(i2c, smsg, error);

			if (ret < 0)

				error = ret;



			if (error < 0)

				goto error;

		}

		mutex_unlock(&vb->lock);

	}

	return 0;

error:

	mutex_unlock(&vb->lock);

	return error;

}



static u32 vprbrd_i2c_func(struct i2c_adapter *i2c)

{

	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;

}



/* This is the actual algorithm we define */

static const struct i2c_algorithm vprbrd_algorithm = {

	.master_xfer	= vprbrd_i2c_xfer,

	.functionality	= vprbrd_i2c_func,

};



static int __devinit vprbrd_i2c_probe(struct platform_device *pdev)

{

	struct vprbrd *vb = dev_get_drvdata(pdev->dev.parent);

	struct vprbrd_i2c *vb_i2c;

	int ret;

	int pipe;



	vb_i2c = kzalloc(sizeof(*vb_i2c), GFP_KERNEL);

	if (vb_i2c == NULL)

		return -ENOMEM;



	/* setup i2c adapter description */

	vb_i2c->i2c.owner = THIS_MODULE;

	vb_i2c->i2c.class = I2C_CLASS_HWMON;

	vb_i2c->i2c.algo = &vprbrd_algorithm;

	vb_i2c->i2c.algo_data = vb;

	/* save the param in usb capabable memory */

	vb_i2c->bus_freq_param = i2c_bus_param;



	snprintf(vb_i2c->i2c.name, sizeof(vb_i2c->i2c.name),

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

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



	/* setting the bus frequency */

	if ((i2c_bus_param <= VPRBRD_I2C_FREQ_10KHZ)

		&& (i2c_bus_param >= VPRBRD_I2C_FREQ_6MHZ)) {

		pipe = usb_sndctrlpipe(vb->usb_dev, 0);

		ret = usb_control_msg(vb->usb_dev, pipe,

			VPRBRD_USB_REQUEST_I2C_FREQ, VPRBRD_USB_TYPE_OUT,

			0x0000, 0x0000, &vb_i2c->bus_freq_param, 1,

			VPRBRD_USB_TIMEOUT_MS);

	    if (ret != 1) {

		dev_err(&pdev->dev,

			"failure setting i2c_bus_freq to %d\n", i2c_bus_freq);

		ret = -EIO;

		goto error;

	    }

	} else {

		dev_err(&pdev->dev,

			"invalid i2c_bus_freq setting:%d\n", i2c_bus_freq);

		ret = -EIO;

		goto error;

	}



	vb_i2c->i2c.dev.parent = &pdev->dev;



	/* attach to i2c layer */

	i2c_add_adapter(&vb_i2c->i2c);



	platform_set_drvdata(pdev, vb_i2c);



	return 0;



error:

	kfree(vb_i2c);

	return ret;

}



static int __devexit vprbrd_i2c_remove(struct platform_device *pdev)

{

	struct vprbrd_i2c *vb_i2c = platform_get_drvdata(pdev);

	int ret;



	ret = i2c_del_adapter(&vb_i2c->i2c);



	return ret;

}



static struct platform_driver vprbrd_i2c_driver = {

	.driver.name	= "viperboard-i2c",

	.driver.owner	= THIS_MODULE,

	.probe		= vprbrd_i2c_probe,

	.remove		= __devexit_p(vprbrd_i2c_remove),

};



static int __init vprbrd_i2c_init(void)

{

	switch (i2c_bus_freq) {

	case 6000:

		i2c_bus_param = VPRBRD_I2C_FREQ_6MHZ;

		break;

	case 3000:

		i2c_bus_param = VPRBRD_I2C_FREQ_3MHZ;

		break;

	case 1000:

		i2c_bus_param = VPRBRD_I2C_FREQ_1MHZ;

		break;

	case 400:

		i2c_bus_param = VPRBRD_I2C_FREQ_400KHZ;

		break;

	case 200:

		i2c_bus_param = VPRBRD_I2C_FREQ_200KHZ;

		break;

	case 100:

		i2c_bus_param = VPRBRD_I2C_FREQ_100KHZ;

		break;

	case 10:

		i2c_bus_param = VPRBRD_I2C_FREQ_10KHZ;

		break;

	default:

		pr_warn("invalid i2c_bus_freq (%d)\n", i2c_bus_freq);

		i2c_bus_param = VPRBRD_I2C_FREQ_100KHZ;

	}



	return platform_driver_register(&vprbrd_i2c_driver);

}

subsys_initcall(vprbrd_i2c_init);



static void __exit vprbrd_i2c_exit(void)

{

	platform_driver_unregister(&vprbrd_i2c_driver);

}

module_exit(vprbrd_i2c_exit);



MODULE_AUTHOR("Lars Poeschel <poeschel@lemonage.de>");

MODULE_DESCRIPTION("I2C master driver for Nano River Techs Viperboard");

MODULE_LICENSE("GPL");

MODULE_ALIAS("platform:viperboard-i2c");

drivers/mfd/viperboard.c

+3 −0
Original line number Diff line number Diff line
@@ -41,6 +41,9 @@ static struct mfd_cell vprbrd_devs[] = { 
	{

		.name = "viperboard-gpio",

	},

	{

		.name = "viperboard-i2c",

	},

};



static int vprbrd_probe(struct usb_interface *interface,

include/linux/mfd/viperboard.h

+2 −0
Original line number Diff line number Diff line
@@ -42,6 +42,8 @@ 
#define VPRBRD_USB_TYPE_OUT	    0x40

#define VPRBRD_USB_TYPE_IN	    0xc0

#define VPRBRD_USB_TIMEOUT_MS       100

#define VPRBRD_USB_REQUEST_I2C_FREQ 0xe6

#define VPRBRD_USB_REQUEST_I2C      0xe9

#define VPRBRD_USB_REQUEST_MAJOR    0xea

#define VPRBRD_USB_REQUEST_MINOR    0xeb

#define VPRBRD_USB_REQUEST_GPIOA    0xed