// SPDX-License-Identifier: GPL-2.0-or-later /* * Nano River Technologies viperboard i2c master driver * * (C) 2012 by Lemonage GmbH * Author: Lars Poeschel <poeschel@lemonage.de> * All rights reserved. */ #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");