diff options
Diffstat (limited to '')
-rw-r--r-- | drivers/i2c/busses/i2c-viperboard.c | 473 |
1 files changed, 473 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-viperboard.c b/drivers/i2c/busses/i2c-viperboard.c new file mode 100644 index 000000000..7235c7302 --- /dev/null +++ b/drivers/i2c/busses/i2c-viperboard.c @@ -0,0 +1,473 @@ +/* + * 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, 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; + 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); + + 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 num; +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 const struct i2c_adapter_quirks vprbrd_quirks = { + .max_read_len = 2048, + .max_write_len = 2048, +}; + +static int 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 = devm_kzalloc(&pdev->dev, 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.quirks = &vprbrd_quirks; + 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); + return -EIO; + } + } else { + dev_err(&pdev->dev, + "invalid i2c_bus_freq setting:%d\n", i2c_bus_freq); + return -EIO; + } + + 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; +} + +static int vprbrd_i2c_remove(struct platform_device *pdev) +{ + struct vprbrd_i2c *vb_i2c = platform_get_drvdata(pdev); + + i2c_del_adapter(&vb_i2c->i2c); + + return 0; +} + +static struct platform_driver vprbrd_i2c_driver = { + .driver.name = "viperboard-i2c", + .driver.owner = THIS_MODULE, + .probe = vprbrd_i2c_probe, + .remove = 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"); |