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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * Nano River Technologies viperboard i2c controller driver4 *5 * (C) 2012 by Lemonage GmbH6 * Author: Lars Poeschel <poeschel@lemonage.de>7 * All rights reserved.8 */9 10#include <linux/kernel.h>11#include <linux/errno.h>12#include <linux/module.h>13#include <linux/slab.h>14#include <linux/types.h>15#include <linux/mutex.h>16#include <linux/platform_device.h>17 18#include <linux/usb.h>19#include <linux/i2c.h>20 21#include <linux/mfd/viperboard.h>22 23struct vprbrd_i2c {24 struct i2c_adapter i2c;25 u8 bus_freq_param;26};27 28/* i2c bus frequency module parameter */29static u8 i2c_bus_param;30static unsigned int i2c_bus_freq = 100;31module_param(i2c_bus_freq, int, 0);32MODULE_PARM_DESC(i2c_bus_freq,33 "i2c bus frequency in khz (default is 100) valid values: 10, 100, 200, 400, 1000, 3000, 6000");34 35static int vprbrd_i2c_status(struct i2c_adapter *i2c,36 struct vprbrd_i2c_status *status, bool prev_error)37{38 u16 bytes_xfer;39 int ret;40 struct vprbrd *vb = (struct vprbrd *)i2c->algo_data;41 42 /* check for protocol error */43 bytes_xfer = sizeof(struct vprbrd_i2c_status);44 45 ret = usb_control_msg(vb->usb_dev, usb_rcvctrlpipe(vb->usb_dev, 0),46 VPRBRD_USB_REQUEST_I2C, VPRBRD_USB_TYPE_IN, 0x0000, 0x0000,47 status, bytes_xfer, VPRBRD_USB_TIMEOUT_MS);48 49 if (ret != bytes_xfer)50 prev_error = true;51 52 if (prev_error) {53 dev_err(&i2c->dev, "failure in usb communication\n");54 return -EREMOTEIO;55 }56 57 dev_dbg(&i2c->dev, " status = %d\n", status->status);58 if (status->status != 0x00) {59 dev_err(&i2c->dev, "failure: i2c protocol error\n");60 return -EPROTO;61 }62 return 0;63}64 65static int vprbrd_i2c_receive(struct usb_device *usb_dev,66 struct vprbrd_i2c_read_msg *rmsg, int bytes_xfer)67{68 int ret, bytes_actual;69 int error = 0;70 71 /* send the read request */72 ret = usb_bulk_msg(usb_dev,73 usb_sndbulkpipe(usb_dev, VPRBRD_EP_OUT), rmsg,74 sizeof(struct vprbrd_i2c_read_hdr), &bytes_actual,75 VPRBRD_USB_TIMEOUT_MS);76 77 if ((ret < 0)78 || (bytes_actual != sizeof(struct vprbrd_i2c_read_hdr))) {79 dev_err(&usb_dev->dev, "failure transmitting usb\n");80 error = -EREMOTEIO;81 }82 83 /* read the actual data */84 ret = usb_bulk_msg(usb_dev,85 usb_rcvbulkpipe(usb_dev, VPRBRD_EP_IN), rmsg,86 bytes_xfer, &bytes_actual, VPRBRD_USB_TIMEOUT_MS);87 88 if ((ret < 0) || (bytes_xfer != bytes_actual)) {89 dev_err(&usb_dev->dev, "failure receiving usb\n");90 error = -EREMOTEIO;91 }92 return error;93}94 95static int vprbrd_i2c_addr(struct usb_device *usb_dev,96 struct vprbrd_i2c_addr_msg *amsg)97{98 int ret, bytes_actual;99 100 ret = usb_bulk_msg(usb_dev,101 usb_sndbulkpipe(usb_dev, VPRBRD_EP_OUT), amsg,102 sizeof(struct vprbrd_i2c_addr_msg), &bytes_actual,103 VPRBRD_USB_TIMEOUT_MS);104 105 if ((ret < 0) ||106 (sizeof(struct vprbrd_i2c_addr_msg) != bytes_actual)) {107 dev_err(&usb_dev->dev, "failure transmitting usb\n");108 return -EREMOTEIO;109 }110 return 0;111}112 113static int vprbrd_i2c_read(struct vprbrd *vb, struct i2c_msg *msg)114{115 int ret;116 u16 remain_len, len1, len2, start = 0x0000;117 struct vprbrd_i2c_read_msg *rmsg =118 (struct vprbrd_i2c_read_msg *)vb->buf;119 120 remain_len = msg->len;121 rmsg->header.cmd = VPRBRD_I2C_CMD_READ;122 while (remain_len > 0) {123 rmsg->header.addr = cpu_to_le16(start + 0x4000);124 if (remain_len <= 255) {125 len1 = remain_len;126 len2 = 0x00;127 rmsg->header.len0 = remain_len;128 rmsg->header.len1 = 0x00;129 rmsg->header.len2 = 0x00;130 rmsg->header.len3 = 0x00;131 rmsg->header.len4 = 0x00;132 rmsg->header.len5 = 0x00;133 remain_len = 0;134 } else if (remain_len <= 510) {135 len1 = remain_len;136 len2 = 0x00;137 rmsg->header.len0 = remain_len - 255;138 rmsg->header.len1 = 0xff;139 rmsg->header.len2 = 0x00;140 rmsg->header.len3 = 0x00;141 rmsg->header.len4 = 0x00;142 rmsg->header.len5 = 0x00;143 remain_len = 0;144 } else if (remain_len <= 512) {145 len1 = remain_len;146 len2 = 0x00;147 rmsg->header.len0 = remain_len - 510;148 rmsg->header.len1 = 0xff;149 rmsg->header.len2 = 0xff;150 rmsg->header.len3 = 0x00;151 rmsg->header.len4 = 0x00;152 rmsg->header.len5 = 0x00;153 remain_len = 0;154 } else if (remain_len <= 767) {155 len1 = 512;156 len2 = remain_len - 512;157 rmsg->header.len0 = 0x02;158 rmsg->header.len1 = 0xff;159 rmsg->header.len2 = 0xff;160 rmsg->header.len3 = remain_len - 512;161 rmsg->header.len4 = 0x00;162 rmsg->header.len5 = 0x00;163 remain_len = 0;164 } else if (remain_len <= 1022) {165 len1 = 512;166 len2 = remain_len - 512;167 rmsg->header.len0 = 0x02;168 rmsg->header.len1 = 0xff;169 rmsg->header.len2 = 0xff;170 rmsg->header.len3 = remain_len - 767;171 rmsg->header.len4 = 0xff;172 rmsg->header.len5 = 0x00;173 remain_len = 0;174 } else if (remain_len <= 1024) {175 len1 = 512;176 len2 = remain_len - 512;177 rmsg->header.len0 = 0x02;178 rmsg->header.len1 = 0xff;179 rmsg->header.len2 = 0xff;180 rmsg->header.len3 = remain_len - 1022;181 rmsg->header.len4 = 0xff;182 rmsg->header.len5 = 0xff;183 remain_len = 0;184 } else {185 len1 = 512;186 len2 = 512;187 rmsg->header.len0 = 0x02;188 rmsg->header.len1 = 0xff;189 rmsg->header.len2 = 0xff;190 rmsg->header.len3 = 0x02;191 rmsg->header.len4 = 0xff;192 rmsg->header.len5 = 0xff;193 remain_len -= 1024;194 start += 1024;195 }196 rmsg->header.tf1 = cpu_to_le16(len1);197 rmsg->header.tf2 = cpu_to_le16(len2);198 199 /* first read transfer */200 ret = vprbrd_i2c_receive(vb->usb_dev, rmsg, len1);201 if (ret < 0)202 return ret;203 /* copy the received data */204 memcpy(msg->buf + start, rmsg, len1);205 206 /* second read transfer if neccessary */207 if (len2 > 0) {208 ret = vprbrd_i2c_receive(vb->usb_dev, rmsg, len2);209 if (ret < 0)210 return ret;211 /* copy the received data */212 memcpy(msg->buf + start + 512, rmsg, len2);213 }214 }215 return 0;216}217 218static int vprbrd_i2c_write(struct vprbrd *vb, struct i2c_msg *msg)219{220 int ret, bytes_actual;221 u16 remain_len, bytes_xfer,222 start = 0x0000;223 struct vprbrd_i2c_write_msg *wmsg =224 (struct vprbrd_i2c_write_msg *)vb->buf;225 226 remain_len = msg->len;227 wmsg->header.cmd = VPRBRD_I2C_CMD_WRITE;228 wmsg->header.last = 0x00;229 wmsg->header.chan = 0x00;230 wmsg->header.spi = 0x0000;231 while (remain_len > 0) {232 wmsg->header.addr = cpu_to_le16(start + 0x4000);233 if (remain_len > 503) {234 wmsg->header.len1 = 0xff;235 wmsg->header.len2 = 0xf8;236 remain_len -= 503;237 bytes_xfer = 503 + sizeof(struct vprbrd_i2c_write_hdr);238 start += 503;239 } else if (remain_len > 255) {240 wmsg->header.len1 = 0xff;241 wmsg->header.len2 = (remain_len - 255);242 bytes_xfer = remain_len +243 sizeof(struct vprbrd_i2c_write_hdr);244 remain_len = 0;245 } else {246 wmsg->header.len1 = remain_len;247 wmsg->header.len2 = 0x00;248 bytes_xfer = remain_len +249 sizeof(struct vprbrd_i2c_write_hdr);250 remain_len = 0;251 }252 memcpy(wmsg->data, msg->buf + start,253 bytes_xfer - sizeof(struct vprbrd_i2c_write_hdr));254 255 ret = usb_bulk_msg(vb->usb_dev,256 usb_sndbulkpipe(vb->usb_dev,257 VPRBRD_EP_OUT), wmsg,258 bytes_xfer, &bytes_actual, VPRBRD_USB_TIMEOUT_MS);259 if ((ret < 0) || (bytes_xfer != bytes_actual))260 return -EREMOTEIO;261 }262 return 0;263}264 265static int vprbrd_i2c_xfer(struct i2c_adapter *i2c, struct i2c_msg *msgs,266 int num)267{268 struct i2c_msg *pmsg;269 int i, ret,270 error = 0;271 struct vprbrd *vb = (struct vprbrd *)i2c->algo_data;272 struct vprbrd_i2c_addr_msg *amsg =273 (struct vprbrd_i2c_addr_msg *)vb->buf;274 struct vprbrd_i2c_status *smsg = (struct vprbrd_i2c_status *)vb->buf;275 276 for (i = 0 ; i < num ; i++) {277 pmsg = &msgs[i];278 279 dev_dbg(&i2c->dev,280 " %d: %s (flags %d) %d bytes to 0x%02x\n",281 i, pmsg->flags & I2C_M_RD ? "read" : "write",282 pmsg->flags, pmsg->len, pmsg->addr);283 284 mutex_lock(&vb->lock);285 /* directly send the message */286 if (pmsg->flags & I2C_M_RD) {287 /* read data */288 amsg->cmd = VPRBRD_I2C_CMD_ADDR;289 amsg->unknown2 = 0x00;290 amsg->unknown3 = 0x00;291 amsg->addr = pmsg->addr;292 amsg->unknown1 = 0x01;293 amsg->len = cpu_to_le16(pmsg->len);294 /* send the addr and len, we're interested to board */295 ret = vprbrd_i2c_addr(vb->usb_dev, amsg);296 if (ret < 0)297 error = ret;298 299 ret = vprbrd_i2c_read(vb, pmsg);300 if (ret < 0)301 error = ret;302 303 ret = vprbrd_i2c_status(i2c, smsg, error);304 if (ret < 0)305 error = ret;306 /* in case of protocol error, return the error */307 if (error < 0)308 goto error;309 } else {310 /* write data */311 ret = vprbrd_i2c_write(vb, pmsg);312 313 amsg->cmd = VPRBRD_I2C_CMD_ADDR;314 amsg->unknown2 = 0x00;315 amsg->unknown3 = 0x00;316 amsg->addr = pmsg->addr;317 amsg->unknown1 = 0x00;318 amsg->len = cpu_to_le16(pmsg->len);319 /* send the addr, the data goes to to board */320 ret = vprbrd_i2c_addr(vb->usb_dev, amsg);321 if (ret < 0)322 error = ret;323 324 ret = vprbrd_i2c_status(i2c, smsg, error);325 if (ret < 0)326 error = ret;327 328 if (error < 0)329 goto error;330 }331 mutex_unlock(&vb->lock);332 }333 return num;334error:335 mutex_unlock(&vb->lock);336 return error;337}338 339static u32 vprbrd_i2c_func(struct i2c_adapter *i2c)340{341 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;342}343 344/* This is the actual algorithm we define */345static const struct i2c_algorithm vprbrd_algorithm = {346 .xfer = vprbrd_i2c_xfer,347 .functionality = vprbrd_i2c_func,348};349 350static const struct i2c_adapter_quirks vprbrd_quirks = {351 .max_read_len = 2048,352 .max_write_len = 2048,353};354 355static int vprbrd_i2c_probe(struct platform_device *pdev)356{357 struct vprbrd *vb = dev_get_drvdata(pdev->dev.parent);358 struct vprbrd_i2c *vb_i2c;359 int ret;360 int pipe;361 362 vb_i2c = devm_kzalloc(&pdev->dev, sizeof(*vb_i2c), GFP_KERNEL);363 if (vb_i2c == NULL)364 return -ENOMEM;365 366 /* setup i2c adapter description */367 vb_i2c->i2c.owner = THIS_MODULE;368 vb_i2c->i2c.class = I2C_CLASS_HWMON;369 vb_i2c->i2c.algo = &vprbrd_algorithm;370 vb_i2c->i2c.quirks = &vprbrd_quirks;371 vb_i2c->i2c.algo_data = vb;372 /* save the param in usb capabable memory */373 vb_i2c->bus_freq_param = i2c_bus_param;374 375 snprintf(vb_i2c->i2c.name, sizeof(vb_i2c->i2c.name),376 "viperboard at bus %03d device %03d",377 vb->usb_dev->bus->busnum, vb->usb_dev->devnum);378 379 /* setting the bus frequency */380 if ((i2c_bus_param <= VPRBRD_I2C_FREQ_10KHZ)381 && (i2c_bus_param >= VPRBRD_I2C_FREQ_6MHZ)) {382 pipe = usb_sndctrlpipe(vb->usb_dev, 0);383 ret = usb_control_msg(vb->usb_dev, pipe,384 VPRBRD_USB_REQUEST_I2C_FREQ, VPRBRD_USB_TYPE_OUT,385 0x0000, 0x0000, &vb_i2c->bus_freq_param, 1,386 VPRBRD_USB_TIMEOUT_MS);387 if (ret != 1) {388 dev_err(&pdev->dev, "failure setting i2c_bus_freq to %d\n",389 i2c_bus_freq);390 return -EIO;391 }392 } else {393 dev_err(&pdev->dev,394 "invalid i2c_bus_freq setting:%d\n", i2c_bus_freq);395 return -EIO;396 }397 398 vb_i2c->i2c.dev.parent = &pdev->dev;399 400 /* attach to i2c layer */401 i2c_add_adapter(&vb_i2c->i2c);402 403 platform_set_drvdata(pdev, vb_i2c);404 405 return 0;406}407 408static void vprbrd_i2c_remove(struct platform_device *pdev)409{410 struct vprbrd_i2c *vb_i2c = platform_get_drvdata(pdev);411 412 i2c_del_adapter(&vb_i2c->i2c);413}414 415static struct platform_driver vprbrd_i2c_driver = {416 .driver.name = "viperboard-i2c",417 .probe = vprbrd_i2c_probe,418 .remove_new = vprbrd_i2c_remove,419};420 421static int __init vprbrd_i2c_init(void)422{423 switch (i2c_bus_freq) {424 case 6000:425 i2c_bus_param = VPRBRD_I2C_FREQ_6MHZ;426 break;427 case 3000:428 i2c_bus_param = VPRBRD_I2C_FREQ_3MHZ;429 break;430 case 1000:431 i2c_bus_param = VPRBRD_I2C_FREQ_1MHZ;432 break;433 case 400:434 i2c_bus_param = VPRBRD_I2C_FREQ_400KHZ;435 break;436 case 200:437 i2c_bus_param = VPRBRD_I2C_FREQ_200KHZ;438 break;439 case 100:440 i2c_bus_param = VPRBRD_I2C_FREQ_100KHZ;441 break;442 case 10:443 i2c_bus_param = VPRBRD_I2C_FREQ_10KHZ;444 break;445 default:446 pr_warn("invalid i2c_bus_freq (%d)\n", i2c_bus_freq);447 i2c_bus_param = VPRBRD_I2C_FREQ_100KHZ;448 }449 450 return platform_driver_register(&vprbrd_i2c_driver);451}452subsys_initcall(vprbrd_i2c_init);453 454static void __exit vprbrd_i2c_exit(void)455{456 platform_driver_unregister(&vprbrd_i2c_driver);457}458module_exit(vprbrd_i2c_exit);459 460MODULE_AUTHOR("Lars Poeschel <poeschel@lemonage.de>");461MODULE_DESCRIPTION("I2C controller driver for Nano River Techs Viperboard");462MODULE_LICENSE("GPL");463MODULE_ALIAS("platform:viperboard-i2c");464