diff mbox

[2/2] i2c: Add bus driver for for OSIF USB i2c device.

Message ID 1388980536-7588-2-git-send-email-andrew@lunn.ch
State Changes Requested
Headers show

Commit Message

Andrew Lunn Jan. 6, 2014, 3:55 a.m. UTC 
OSIF, Open Source InterFace, is a USB based i2c bus master.  The
origional design was based on i2c-tiny-usb, but more modern versions
of the firmware running on the MegaAVR microcontroller use a different
protocol over the USB. This code is based on Barry Carter
<barry.carter@gmail.com> driver.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
CC: Emmanuel Deloget <logout@free.fr>
CC: Barry Carter <barry.carter@gmail.com>
---
v2:

Rearranged order of functions to remove forward declarations
Remove some obvious comments
Remove debug prints which the core also provides
Remove defines for module authors.
Allocate status byte once in priv, rather than for each xfer.
Fix MODULE_LICENSE()
Rename file and Kconfig entry for consistency and ordering.
Inline osif_free()
---
 drivers/i2c/busses/Kconfig              |   10 ++
 drivers/i2c/busses/Makefile             |    1 +
 drivers/i2c/busses/i2c-robotfuzz-osif.c |  201 +++++++++++++++++++++++++++++++
 3 files changed, 212 insertions(+)
 create mode 100644 drivers/i2c/busses/i2c-robotfuzz-osif.c

Comments

Wolfram Sang Jan. 9, 2014, 9:49 p.m. UTC | #1 
On Mon, Jan 06, 2014 at 04:55:36AM +0100, Andrew Lunn wrote:
> OSIF, Open Source InterFace, is a USB based i2c bus master.  The
> origional design was based on i2c-tiny-usb, but more modern versions
> of the firmware running on the MegaAVR microcontroller use a different
> protocol over the USB. This code is based on Barry Carter
> <barry.carter@gmail.com> driver.
> 
> Signed-off-by: Andrew Lunn <andrew@lunn.ch>

We are getting close...


> +#define OSIFI2C_READ		20 /* Read from i2c bus */
> +#define OSIFI2C_WRITE		21 /* Write to i2c bus */
> +#define OSIFI2C_STOP		22 /* Send stop condition */
> +#define OSIFI2C_STATUS		23 /* Get status from i2c action */
> +#define OSIFI2C_SET_BIT_RATE	24 /* Set the bit rate & prescaler */

Comments could be seen as obvious, too. I'll leave the decision to you.

> +struct priv {

Namespace: 'osif_priv' please.

> +	struct usb_device *usb_dev;
> +	struct usb_interface *interface;
> +	struct i2c_adapter adapter;
> +	unsigned char status;
> +};
> +
> +static int usb_read(struct i2c_adapter *adapter, int cmd,

Namespace: 'osif_usb_read'.

> +		    int value, int index, void *data, int len)
> +{
> +	struct priv *priv = (struct priv *)adapter->algo_data;

No need to cast a void*.

> +
> +	return usb_control_msg(priv->usb_dev, usb_rcvctrlpipe(priv->usb_dev, 0),
> +			       cmd, USB_TYPE_VENDOR | USB_RECIP_INTERFACE |
> +			       USB_DIR_IN, value, index, data, len, 2000);
> +}
> +
> +static int usb_write(struct i2c_adapter *adapter, int cmd,

Namespace

> +		    int value, int index, void *data, int len)
> +{
> +
> +	struct priv *priv = (struct priv *)adapter->algo_data;

no cast.

> +
> +	return usb_control_msg(priv->usb_dev, usb_sndctrlpipe(priv->usb_dev, 0),
> +			       cmd, USB_TYPE_VENDOR | USB_RECIP_INTERFACE,
> +			       value, index, data, len, 2000);
> +}
> +
> +static int usb_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, int num)

namespace

> +{
> +	struct priv *priv = (struct priv *)adapter->algo_data;

no cast

> +	struct i2c_msg *pmsg;
> +	int ret = 0;
> +	int i, cmd;
> +
> +	for (i = 0; ret >= 0 && i < num; i++) {
> +		pmsg = &msgs[i];
> +
> +		if (pmsg->flags & I2C_M_RD) {
> +			cmd = OSIFI2C_READ;
> +
> +			ret = usb_read(adapter, cmd, pmsg->flags, pmsg->addr,
> +				       pmsg->buf, pmsg->len);
> +			if (ret != pmsg->len) {
> +				dev_err(&adapter->dev,
> +					"failure reading data\n");

One line is more readable IMO. 80 chars is not a hard limit.

> +				return -EREMOTEIO;
> +			}
> +		} else {
> +			cmd = OSIFI2C_WRITE;
> +
> +			ret = usb_write(adapter, cmd, pmsg->flags, pmsg->addr,
> +					pmsg->buf, pmsg->len);
> +			if (ret != pmsg->len) {
> +				dev_err(&adapter->dev,
> +					"failure writing data\n");

ditto

> +				return -EREMOTEIO;
> +			}
> +		}
> +
> +		ret = usb_read(adapter, OSIFI2C_STOP, 0, 0, NULL, 0);
> +		if (ret != 0) {

'if (ret)' is enough

> +			dev_err(&adapter->dev, "failure sending STOP\n");
> +			return -EREMOTEIO;
> +		}
> +
> +		/* read status */
> +		ret = usb_read(adapter, OSIFI2C_STATUS, 0, 0, &priv->status, 1);
> +		if (ret != 1) {
> +			dev_err(&adapter->dev, "failure reading status\n");
> +			return -EREMOTEIO;
> +		}
> +
> +		if (priv->status != STATUS_ADDRESS_ACK) {
> +			dev_dbg(&adapter->dev, "status = %d\n", priv->status);
> +			return -EREMOTEIO;
> +		}
> +	}
> +
> +	return i;
> +}
> +
> +static u32 usb_func(struct i2c_adapter *adapter)
> +{
> +	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;

Have you tried SMBUS_QUICK by the way?

> +}
> +
> +static struct i2c_algorithm usb_algorithm = {
> +	.master_xfer	= usb_xfer,
> +	.functionality	= usb_func,
> +};
> +
> +#define USB_OSIF_VENDOR_ID	0x1964
> +#define USB_OSIF_PRODUCT_ID	0x0001
> +
> +static struct usb_device_id osif_table[] = {
> +	{ USB_DEVICE(USB_OSIF_VENDOR_ID, USB_OSIF_PRODUCT_ID) },
> +	{ }
> +};
> +

Empty line can go.

> +MODULE_DEVICE_TABLE(usb, osif_table);
> +
> +static int osif_probe(struct usb_interface *interface,
> +			     const struct usb_device_id *id)
> +{
> +	int retval;

maybe just 'ret' for consistency? Very minor nit, though...

> +	struct priv *priv;
> +	u16 version;

Rest looks ready to go!
Andrew Lunn Jan. 10, 2014, 6:01 p.m. UTC | #2 
Hi Wolfgang

> > +static u32 usb_func(struct i2c_adapter *adapter)
> > +{
> > +	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
> 
> Have you tried SMBUS_QUICK by the way?

Nope, not tried it.

Documentation/i2c/smbus-protocol say:

SMBus Quick Command
===================

This sends a single bit to the device, at the place of the Rd/Wr bit.

A Addr Rd/Wr [A] P

Functionality flag: I2C_FUNC_SMBUS_QUICK

My first question is probably silly. Should the first A be an S?

So is this a zero byte transfer? Is that not what i2cdetect does?
I've used i2cdetect on this hardware to find my devices.

Thanks
	Andrew
--
To unsubscribe from this list: send the line "unsubscribe linux-i2c" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Wolfram Sang Jan. 10, 2014, 6:16 p.m. UTC | #3 
Hi,

> Hi Wolfgang

Wolfram

> So is this a zero byte transfer? Is that not what i2cdetect does?

Yes, you can enforce it with -q. It will do it for some addresses
automatically and complain if it is not available. So, seems to work,
great!
Andrew Lunn Jan. 10, 2014, 7:21 p.m. UTC | #4 
Hi Wolfram

> > Hi Wolfgang
> 
> Wolfram

Upps, Sorry.

> > So is this a zero byte transfer? Is that not what i2cdetect does?
> 
> Yes, you can enforce it with -q. It will do it for some addresses
> automatically and complain if it is not available. So, seems to work,
> great!

O.K, i will double check and then add this to functions.

     Andrew 


--
To unsubscribe from this list: send the line "unsubscribe linux-i2c" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Wolfram Sang Jan. 10, 2014, 7:25 p.m. UTC | #5 
> O.K, i will double check and then add this to functions.

It's default on :)
diff mbox

Patch

diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index cdcbd8368ed3..ed1bd7a46c20 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -837,6 +837,16 @@  config I2C_PARPORT_LIGHT
 	  This support is also available as a module.  If so, the module
 	  will be called i2c-parport-light.
 
+config I2C_ROBOTFUZZ_OSIF
+	tristate "RobotFuzz Open Source InterFace USB adapter"
+	depends on USB
+	help
+	  If you say yes to this option, support will be included for the
+	  RobotFuzz Open Source InterFace USB to I2C interface.
+
+	  This driver can also be built as a module.  If so, the module
+	  will be called i2c-osif.
+
 config I2C_TAOS_EVM
 	tristate "TAOS evaluation module"
 	depends on TTY
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index d00997f3eb3b..f171fa8b1a72 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -81,6 +81,7 @@  obj-$(CONFIG_I2C_RCAR)		+= i2c-rcar.o
 obj-$(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-$(CONFIG_I2C_ROBOTFUZZ_OSIF)	+= i2c-robotfuzz-osif.o
 obj-$(CONFIG_I2C_TAOS_EVM)	+= i2c-taos-evm.o
 obj-$(CONFIG_I2C_TINY_USB)	+= i2c-tiny-usb.o
 obj-$(CONFIG_I2C_VIPERBOARD)	+= i2c-viperboard.o
diff --git a/drivers/i2c/busses/i2c-robotfuzz-osif.c b/drivers/i2c/busses/i2c-robotfuzz-osif.c
new file mode 100644
index 000000000000..3e03c008775a
--- /dev/null
+++ b/drivers/i2c/busses/i2c-robotfuzz-osif.c
@@ -0,0 +1,201 @@ 
+/*
+ * Driver for RobotFuzz OSIF
+ *
+ * Copyright (c) 2013 Andrew Lunn <andrew@lunn.ch>
+ * Copyright (c) 2007 Barry Carter <Barry.Carter@robotfuzz.com>
+ *
+ * Based on the i2c-tiny-usb by
+ *
+ * Copyright (C) 2006 Til 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/module.h>
+#include <linux/errno.h>
+#include <linux/i2c.h>
+#include <linux/slab.h>
+#include <linux/usb.h>
+
+#define OSIFI2C_READ		20 /* Read from i2c bus */
+#define OSIFI2C_WRITE		21 /* Write to i2c bus */
+#define OSIFI2C_STOP		22 /* Send stop condition */
+#define OSIFI2C_STATUS		23 /* Get status from i2c action */
+#define OSIFI2C_SET_BIT_RATE	24 /* Set the bit rate & prescaler */
+
+#define STATUS_ADDRESS_ACK	0
+#define STATUS_ADDRESS_NAK	2
+
+struct priv {
+	struct usb_device *usb_dev;
+	struct usb_interface *interface;
+	struct i2c_adapter adapter;
+	unsigned char status;
+};
+
+static int usb_read(struct i2c_adapter *adapter, int cmd,
+		    int value, int index, void *data, int len)
+{
+	struct priv *priv = (struct priv *)adapter->algo_data;
+
+	return usb_control_msg(priv->usb_dev, usb_rcvctrlpipe(priv->usb_dev, 0),
+			       cmd, USB_TYPE_VENDOR | USB_RECIP_INTERFACE |
+			       USB_DIR_IN, value, index, data, len, 2000);
+}
+
+static int usb_write(struct i2c_adapter *adapter, int cmd,
+		    int value, int index, void *data, int len)
+{
+
+	struct priv *priv = (struct priv *)adapter->algo_data;
+
+	return usb_control_msg(priv->usb_dev, usb_sndctrlpipe(priv->usb_dev, 0),
+			       cmd, USB_TYPE_VENDOR | USB_RECIP_INTERFACE,
+			       value, index, data, len, 2000);
+}
+
+static int usb_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, int num)
+{
+	struct priv *priv = (struct priv *)adapter->algo_data;
+	struct i2c_msg *pmsg;
+	int ret = 0;
+	int i, cmd;
+
+	for (i = 0; ret >= 0 && i < num; i++) {
+		pmsg = &msgs[i];
+
+		if (pmsg->flags & I2C_M_RD) {
+			cmd = OSIFI2C_READ;
+
+			ret = usb_read(adapter, cmd, pmsg->flags, pmsg->addr,
+				       pmsg->buf, pmsg->len);
+			if (ret != pmsg->len) {
+				dev_err(&adapter->dev,
+					"failure reading data\n");
+				return -EREMOTEIO;
+			}
+		} else {
+			cmd = OSIFI2C_WRITE;
+
+			ret = usb_write(adapter, cmd, pmsg->flags, pmsg->addr,
+					pmsg->buf, pmsg->len);
+			if (ret != pmsg->len) {
+				dev_err(&adapter->dev,
+					"failure writing data\n");
+				return -EREMOTEIO;
+			}
+		}
+
+		ret = usb_read(adapter, OSIFI2C_STOP, 0, 0, NULL, 0);
+		if (ret != 0) {
+			dev_err(&adapter->dev, "failure sending STOP\n");
+			return -EREMOTEIO;
+		}
+
+		/* read status */
+		ret = usb_read(adapter, OSIFI2C_STATUS, 0, 0, &priv->status, 1);
+		if (ret != 1) {
+			dev_err(&adapter->dev, "failure reading status\n");
+			return -EREMOTEIO;
+		}
+
+		if (priv->status != STATUS_ADDRESS_ACK) {
+			dev_dbg(&adapter->dev, "status = %d\n", priv->status);
+			return -EREMOTEIO;
+		}
+	}
+
+	return i;
+}
+
+static u32 usb_func(struct i2c_adapter *adapter)
+{
+	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
+}
+
+static struct i2c_algorithm usb_algorithm = {
+	.master_xfer	= usb_xfer,
+	.functionality	= usb_func,
+};
+
+#define USB_OSIF_VENDOR_ID	0x1964
+#define USB_OSIF_PRODUCT_ID	0x0001
+
+static struct usb_device_id osif_table[] = {
+	{ USB_DEVICE(USB_OSIF_VENDOR_ID, USB_OSIF_PRODUCT_ID) },
+	{ }
+};
+
+MODULE_DEVICE_TABLE(usb, osif_table);
+
+static int osif_probe(struct usb_interface *interface,
+			     const struct usb_device_id *id)
+{
+	int retval;
+	struct priv *priv;
+	u16 version;
+
+	priv = devm_kzalloc(&interface->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->usb_dev = usb_get_dev(interface_to_usbdev(interface));
+	priv->interface = interface;
+
+	usb_set_intfdata(interface, priv);
+
+	priv->adapter.owner = THIS_MODULE;
+	priv->adapter.class = I2C_CLASS_HWMON;
+	priv->adapter.algo = &usb_algorithm;
+	priv->adapter.algo_data = priv;
+	snprintf(priv->adapter.name, sizeof(priv->adapter.name),
+		 "OSIF at bus %03d device %03d",
+		 priv->usb_dev->bus->busnum, priv->usb_dev->devnum);
+
+	/*
+	 * Set bus frequency. The frequency is:
+	 * 120,000,000 / ( 16 + 2 * div * 4^prescale).
+	 * Using dev = 52, prescale = 0 give 100KHz */
+	retval = usb_read(&priv->adapter, OSIFI2C_SET_BIT_RATE, 52, 0, NULL, 0);
+	if (retval) {
+		dev_err(&interface->dev, "failure sending bit rate");
+		usb_put_dev(priv->usb_dev);
+		return retval;
+	}
+
+	i2c_add_adapter(&(priv->adapter));
+
+	version = le16_to_cpu(priv->usb_dev->descriptor.bcdDevice);
+	dev_info(&interface->dev,
+		 "version %x.%02x found at bus %03d address %03d",
+		 version >> 8, version & 0xff,
+		 priv->usb_dev->bus->busnum, priv->usb_dev->devnum);
+
+	return 0;
+}
+
+static void osif_disconnect(struct usb_interface *interface)
+{
+	struct priv *priv = usb_get_intfdata(interface);
+
+	i2c_del_adapter(&(priv->adapter));
+	usb_set_intfdata(interface, NULL);
+	usb_put_dev(priv->usb_dev);
+}
+
+static struct usb_driver osif_driver = {
+	.name		= "RobotFuzz Open Source InterFace, OSIF",
+	.probe		= osif_probe,
+	.disconnect	= osif_disconnect,
+	.id_table	= osif_table,
+};
+
+module_usb_driver(osif_driver);
+
+MODULE_AUTHOR("Andrew Lunn <andrew@lunn.ch>");
+MODULE_AUTHOR("Barry Carter <barry.carter@robotfuzz.com>");
+MODULE_DESCRIPTION("RobotFuzz OSIF driver");
+MODULE_LICENSE("GPL v2");