i2c: Add bus driver for for OSIF USB i2c device.

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>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

3 files changed, 213 insertions, 0 deletions

diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 98a3f1ffc3b7..6bcdea5856af 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -874,6 +874,16 @@ 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 dca041b1b99d..a08931fe73e1 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -84,6 +84,7 @@ 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..ced9c6a308d1
--- /dev/null
+++ b/drivers/i2c/busses/i2c-robotfuzz-osif.c
@@ -0,0 +1,202 @@
+/*
+ * 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
+#define OSIFI2C_WRITE           21
+#define OSIFI2C_STOP            22
+#define OSIFI2C_STATUS          23
+#define OSIFI2C_SET_BIT_RATE    24
+
+#define STATUS_ADDRESS_ACK      0
+#define STATUS_ADDRESS_NAK      2
+
+struct osif_priv {
+        struct usb_device *usb_dev;
+        struct usb_interface *interface;
+        struct i2c_adapter adapter;
+        unsigned char status;
+};
+
+static int osif_usb_read(struct i2c_adapter *adapter, int cmd,
+                         int value, int index, void *data, int len)
+{
+        struct osif_priv *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 osif_usb_write(struct i2c_adapter *adapter, int cmd,
+                          int value, int index, void *data, int len)
+{
+
+        struct osif_priv *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 osif_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs,
+                         int num)
+{
+        struct osif_priv *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 = osif_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 = osif_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 = osif_usb_read(adapter, OSIFI2C_STOP, 0, 0, NULL, 0);
+                if (ret) {
+                        dev_err(&adapter->dev, "failure sending STOP\n");
+                        return -EREMOTEIO;
+                }
+
+                /* read status */
+                ret = osif_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 osif_func(struct i2c_adapter *adapter)
+{
+        return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
+}
+
+static struct i2c_algorithm osif_algorithm = {
+        .master_xfer    = osif_xfer,
+        .functionality  = osif_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 ret;
+        struct osif_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 = &osif_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 */
+        ret = osif_usb_read(&priv->adapter, OSIFI2C_SET_BIT_RATE, 52, 0,
+                            NULL, 0);
+        if (ret) {
+                dev_err(&interface->dev, "failure sending bit rate");
+                usb_put_dev(priv->usb_dev);
+                return ret;
+        }
+
+        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 osif_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");