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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Driver for the Diolan u2c-12 USB-I2C adapter4 *5 * Copyright (c) 2010-2011 Ericsson AB6 *7 * Derived from:8 * i2c-tiny-usb.c9 * Copyright (C) 2006-2007 Till Harbaum (Till@Harbaum.org)10 */11 12#include <linux/kernel.h>13#include <linux/errno.h>14#include <linux/module.h>15#include <linux/types.h>16#include <linux/slab.h>17#include <linux/usb.h>18#include <linux/i2c.h>19 20#define DRIVER_NAME "i2c-diolan-u2c"21 22#define USB_VENDOR_ID_DIOLAN 0x0abf23#define USB_DEVICE_ID_DIOLAN_U2C 0x337024 25 26/* commands via USB, must match command ids in the firmware */27#define CMD_I2C_READ 0x0128#define CMD_I2C_WRITE 0x0229#define CMD_I2C_SCAN 0x03 /* Returns list of detected devices */30#define CMD_I2C_RELEASE_SDA 0x0431#define CMD_I2C_RELEASE_SCL 0x0532#define CMD_I2C_DROP_SDA 0x0633#define CMD_I2C_DROP_SCL 0x0734#define CMD_I2C_READ_SDA 0x0835#define CMD_I2C_READ_SCL 0x0936#define CMD_GET_FW_VERSION 0x0a37#define CMD_GET_SERIAL 0x0b38#define CMD_I2C_START 0x0c39#define CMD_I2C_STOP 0x0d40#define CMD_I2C_REPEATED_START 0x0e41#define CMD_I2C_PUT_BYTE 0x0f42#define CMD_I2C_GET_BYTE 0x1043#define CMD_I2C_PUT_ACK 0x1144#define CMD_I2C_GET_ACK 0x1245#define CMD_I2C_PUT_BYTE_ACK 0x1346#define CMD_I2C_GET_BYTE_ACK 0x1447#define CMD_I2C_SET_SPEED 0x1b48#define CMD_I2C_GET_SPEED 0x1c49#define CMD_I2C_SET_CLK_SYNC 0x2450#define CMD_I2C_GET_CLK_SYNC 0x2551#define CMD_I2C_SET_CLK_SYNC_TO 0x2652#define CMD_I2C_GET_CLK_SYNC_TO 0x2753 54#define RESP_OK 0x0055#define RESP_FAILED 0x0156#define RESP_BAD_MEMADDR 0x0457#define RESP_DATA_ERR 0x0558#define RESP_NOT_IMPLEMENTED 0x0659#define RESP_NACK 0x0760#define RESP_TIMEOUT 0x0961 62#define U2C_I2C_SPEED_FAST 0 /* 400 kHz */63#define U2C_I2C_SPEED_STD 1 /* 100 kHz */64#define U2C_I2C_SPEED_2KHZ 242 /* 2 kHz, minimum speed */65#define U2C_I2C_SPEED(f) ((DIV_ROUND_UP(1000000, (f)) - 10) / 2 + 1)66 67#define U2C_I2C_FREQ(s) (1000000 / (2 * (s - 1) + 10))68 69#define DIOLAN_USB_TIMEOUT 100 /* in ms */70#define DIOLAN_SYNC_TIMEOUT 20 /* in ms */71 72#define DIOLAN_OUTBUF_LEN 12873#define DIOLAN_FLUSH_LEN (DIOLAN_OUTBUF_LEN - 4)74#define DIOLAN_INBUF_LEN 256 /* Maximum supported receive length */75 76/* Structure to hold all of our device specific stuff */77struct i2c_diolan_u2c {78 u8 obuffer[DIOLAN_OUTBUF_LEN]; /* output buffer */79 u8 ibuffer[DIOLAN_INBUF_LEN]; /* input buffer */80 int ep_in, ep_out; /* Endpoints */81 struct usb_device *usb_dev; /* the usb device for this device */82 struct usb_interface *interface;/* the interface for this device */83 struct i2c_adapter adapter; /* i2c related things */84 int olen; /* Output buffer length */85 int ocount; /* Number of enqueued messages */86};87 88static uint frequency = I2C_MAX_STANDARD_MODE_FREQ; /* I2C clock frequency in Hz */89 90module_param(frequency, uint, S_IRUGO | S_IWUSR);91MODULE_PARM_DESC(frequency, "I2C clock frequency in hertz");92 93/* usb layer */94 95/* Send command to device, and get response. */96static int diolan_usb_transfer(struct i2c_diolan_u2c *dev)97{98 int ret = 0;99 int actual;100 int i;101 102 if (!dev->olen || !dev->ocount)103 return -EINVAL;104 105 ret = usb_bulk_msg(dev->usb_dev,106 usb_sndbulkpipe(dev->usb_dev, dev->ep_out),107 dev->obuffer, dev->olen, &actual,108 DIOLAN_USB_TIMEOUT);109 if (!ret) {110 for (i = 0; i < dev->ocount; i++) {111 int tmpret;112 113 tmpret = usb_bulk_msg(dev->usb_dev,114 usb_rcvbulkpipe(dev->usb_dev,115 dev->ep_in),116 dev->ibuffer,117 sizeof(dev->ibuffer), &actual,118 DIOLAN_USB_TIMEOUT);119 /*120 * Stop command processing if a previous command121 * returned an error.122 * Note that we still need to retrieve all messages.123 */124 if (ret < 0)125 continue;126 ret = tmpret;127 if (ret == 0 && actual > 0) {128 switch (dev->ibuffer[actual - 1]) {129 case RESP_NACK:130 /*131 * Return ENXIO if NACK was received as132 * response to the address phase,133 * EIO otherwise134 */135 ret = i == 1 ? -ENXIO : -EIO;136 break;137 case RESP_TIMEOUT:138 ret = -ETIMEDOUT;139 break;140 case RESP_OK:141 /* strip off return code */142 ret = actual - 1;143 break;144 default:145 ret = -EIO;146 break;147 }148 }149 }150 }151 dev->olen = 0;152 dev->ocount = 0;153 return ret;154}155 156static int diolan_write_cmd(struct i2c_diolan_u2c *dev, bool flush)157{158 if (flush || dev->olen >= DIOLAN_FLUSH_LEN)159 return diolan_usb_transfer(dev);160 return 0;161}162 163/* Send command (no data) */164static int diolan_usb_cmd(struct i2c_diolan_u2c *dev, u8 command, bool flush)165{166 dev->obuffer[dev->olen++] = command;167 dev->ocount++;168 return diolan_write_cmd(dev, flush);169}170 171/* Send command with one byte of data */172static int diolan_usb_cmd_data(struct i2c_diolan_u2c *dev, u8 command, u8 data,173 bool flush)174{175 dev->obuffer[dev->olen++] = command;176 dev->obuffer[dev->olen++] = data;177 dev->ocount++;178 return diolan_write_cmd(dev, flush);179}180 181/* Send command with two bytes of data */182static int diolan_usb_cmd_data2(struct i2c_diolan_u2c *dev, u8 command, u8 d1,183 u8 d2, bool flush)184{185 dev->obuffer[dev->olen++] = command;186 dev->obuffer[dev->olen++] = d1;187 dev->obuffer[dev->olen++] = d2;188 dev->ocount++;189 return diolan_write_cmd(dev, flush);190}191 192/*193 * Flush input queue.194 * If we don't do this at startup and the controller has queued up195 * messages which were not retrieved, it will stop responding196 * at some point.197 */198static void diolan_flush_input(struct i2c_diolan_u2c *dev)199{200 int i;201 202 for (i = 0; i < 10; i++) {203 int actual = 0;204 int ret;205 206 ret = usb_bulk_msg(dev->usb_dev,207 usb_rcvbulkpipe(dev->usb_dev, dev->ep_in),208 dev->ibuffer, sizeof(dev->ibuffer), &actual,209 DIOLAN_USB_TIMEOUT);210 if (ret < 0 || actual == 0)211 break;212 }213 if (i == 10)214 dev_err(&dev->interface->dev, "Failed to flush input buffer\n");215}216 217static int diolan_i2c_start(struct i2c_diolan_u2c *dev)218{219 return diolan_usb_cmd(dev, CMD_I2C_START, false);220}221 222static int diolan_i2c_repeated_start(struct i2c_diolan_u2c *dev)223{224 return diolan_usb_cmd(dev, CMD_I2C_REPEATED_START, false);225}226 227static int diolan_i2c_stop(struct i2c_diolan_u2c *dev)228{229 return diolan_usb_cmd(dev, CMD_I2C_STOP, true);230}231 232static int diolan_i2c_get_byte_ack(struct i2c_diolan_u2c *dev, bool ack,233 u8 *byte)234{235 int ret;236 237 ret = diolan_usb_cmd_data(dev, CMD_I2C_GET_BYTE_ACK, ack, true);238 if (ret > 0)239 *byte = dev->ibuffer[0];240 else if (ret == 0)241 ret = -EIO;242 243 return ret;244}245 246static int diolan_i2c_put_byte_ack(struct i2c_diolan_u2c *dev, u8 byte)247{248 return diolan_usb_cmd_data(dev, CMD_I2C_PUT_BYTE_ACK, byte, false);249}250 251static int diolan_set_speed(struct i2c_diolan_u2c *dev, u8 speed)252{253 return diolan_usb_cmd_data(dev, CMD_I2C_SET_SPEED, speed, true);254}255 256/* Enable or disable clock synchronization (stretching) */257static int diolan_set_clock_synch(struct i2c_diolan_u2c *dev, bool enable)258{259 return diolan_usb_cmd_data(dev, CMD_I2C_SET_CLK_SYNC, enable, true);260}261 262/* Set clock synchronization timeout in ms */263static int diolan_set_clock_synch_timeout(struct i2c_diolan_u2c *dev, int ms)264{265 int to_val = ms * 10;266 267 return diolan_usb_cmd_data2(dev, CMD_I2C_SET_CLK_SYNC_TO,268 to_val & 0xff, (to_val >> 8) & 0xff, true);269}270 271static void diolan_fw_version(struct i2c_diolan_u2c *dev)272{273 int ret;274 275 ret = diolan_usb_cmd(dev, CMD_GET_FW_VERSION, true);276 if (ret >= 2)277 dev_info(&dev->interface->dev,278 "Diolan U2C firmware version %u.%u\n",279 (unsigned int)dev->ibuffer[0],280 (unsigned int)dev->ibuffer[1]);281}282 283static void diolan_get_serial(struct i2c_diolan_u2c *dev)284{285 int ret;286 u32 serial;287 288 ret = diolan_usb_cmd(dev, CMD_GET_SERIAL, true);289 if (ret >= 4) {290 serial = le32_to_cpu(*(u32 *)dev->ibuffer);291 dev_info(&dev->interface->dev,292 "Diolan U2C serial number %u\n", serial);293 }294}295 296static int diolan_init(struct i2c_diolan_u2c *dev)297{298 int speed, ret;299 300 if (frequency >= 2 * I2C_MAX_STANDARD_MODE_FREQ) {301 speed = U2C_I2C_SPEED_FAST;302 frequency = I2C_MAX_FAST_MODE_FREQ;303 } else if (frequency >= I2C_MAX_STANDARD_MODE_FREQ || frequency == 0) {304 speed = U2C_I2C_SPEED_STD;305 frequency = I2C_MAX_STANDARD_MODE_FREQ;306 } else {307 speed = U2C_I2C_SPEED(frequency);308 if (speed > U2C_I2C_SPEED_2KHZ)309 speed = U2C_I2C_SPEED_2KHZ;310 frequency = U2C_I2C_FREQ(speed);311 }312 313 dev_info(&dev->interface->dev,314 "Diolan U2C at USB bus %03d address %03d speed %d Hz\n",315 dev->usb_dev->bus->busnum, dev->usb_dev->devnum, frequency);316 317 diolan_flush_input(dev);318 diolan_fw_version(dev);319 diolan_get_serial(dev);320 321 /* Set I2C speed */322 ret = diolan_set_speed(dev, speed);323 if (ret < 0)324 return ret;325 326 /* Configure I2C clock synchronization */327 ret = diolan_set_clock_synch(dev, speed != U2C_I2C_SPEED_FAST);328 if (ret < 0)329 return ret;330 331 if (speed != U2C_I2C_SPEED_FAST)332 ret = diolan_set_clock_synch_timeout(dev, DIOLAN_SYNC_TIMEOUT);333 334 return ret;335}336 337/* i2c layer */338 339static int diolan_usb_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs,340 int num)341{342 struct i2c_diolan_u2c *dev = i2c_get_adapdata(adapter);343 struct i2c_msg *pmsg;344 int i, j;345 int ret, sret;346 347 ret = diolan_i2c_start(dev);348 if (ret < 0)349 return ret;350 351 for (i = 0; i < num; i++) {352 pmsg = &msgs[i];353 if (i) {354 ret = diolan_i2c_repeated_start(dev);355 if (ret < 0)356 goto abort;357 }358 ret = diolan_i2c_put_byte_ack(dev,359 i2c_8bit_addr_from_msg(pmsg));360 if (ret < 0)361 goto abort;362 if (pmsg->flags & I2C_M_RD) {363 for (j = 0; j < pmsg->len; j++) {364 u8 byte;365 bool ack = j < pmsg->len - 1;366 367 /*368 * Don't send NACK if this is the first byte369 * of a SMBUS_BLOCK message.370 */371 if (j == 0 && (pmsg->flags & I2C_M_RECV_LEN))372 ack = true;373 374 ret = diolan_i2c_get_byte_ack(dev, ack, &byte);375 if (ret < 0)376 goto abort;377 /*378 * Adjust count if first received byte is length379 */380 if (j == 0 && (pmsg->flags & I2C_M_RECV_LEN)) {381 if (byte == 0382 || byte > I2C_SMBUS_BLOCK_MAX) {383 ret = -EPROTO;384 goto abort;385 }386 pmsg->len += byte;387 }388 pmsg->buf[j] = byte;389 }390 } else {391 for (j = 0; j < pmsg->len; j++) {392 ret = diolan_i2c_put_byte_ack(dev,393 pmsg->buf[j]);394 if (ret < 0)395 goto abort;396 }397 }398 }399 ret = num;400abort:401 sret = diolan_i2c_stop(dev);402 if (sret < 0 && ret >= 0)403 ret = sret;404 return ret;405}406 407/*408 * Return list of supported functionality.409 */410static u32 diolan_usb_func(struct i2c_adapter *a)411{412 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |413 I2C_FUNC_SMBUS_READ_BLOCK_DATA | I2C_FUNC_SMBUS_BLOCK_PROC_CALL;414}415 416static const struct i2c_algorithm diolan_usb_algorithm = {417 .xfer = diolan_usb_xfer,418 .functionality = diolan_usb_func,419};420 421/* device layer */422 423static const struct usb_device_id diolan_u2c_table[] = {424 { USB_DEVICE(USB_VENDOR_ID_DIOLAN, USB_DEVICE_ID_DIOLAN_U2C) },425 { }426};427 428MODULE_DEVICE_TABLE(usb, diolan_u2c_table);429 430static void diolan_u2c_free(struct i2c_diolan_u2c *dev)431{432 usb_put_dev(dev->usb_dev);433 kfree(dev);434}435 436static int diolan_u2c_probe(struct usb_interface *interface,437 const struct usb_device_id *id)438{439 struct usb_host_interface *hostif = interface->cur_altsetting;440 struct i2c_diolan_u2c *dev;441 int ret;442 443 if (hostif->desc.bInterfaceNumber != 0444 || hostif->desc.bNumEndpoints < 2)445 return -ENODEV;446 447 /* allocate memory for our device state and initialize it */448 dev = kzalloc(sizeof(*dev), GFP_KERNEL);449 if (dev == NULL) {450 ret = -ENOMEM;451 goto error;452 }453 dev->ep_out = hostif->endpoint[0].desc.bEndpointAddress;454 dev->ep_in = hostif->endpoint[1].desc.bEndpointAddress;455 456 dev->usb_dev = usb_get_dev(interface_to_usbdev(interface));457 dev->interface = interface;458 459 /* save our data pointer in this interface device */460 usb_set_intfdata(interface, dev);461 462 /* setup i2c adapter description */463 dev->adapter.owner = THIS_MODULE;464 dev->adapter.class = I2C_CLASS_HWMON;465 dev->adapter.algo = &diolan_usb_algorithm;466 i2c_set_adapdata(&dev->adapter, dev);467 snprintf(dev->adapter.name, sizeof(dev->adapter.name),468 DRIVER_NAME " at bus %03d device %03d",469 dev->usb_dev->bus->busnum, dev->usb_dev->devnum);470 471 dev->adapter.dev.parent = &dev->interface->dev;472 473 /* initialize diolan i2c interface */474 ret = diolan_init(dev);475 if (ret < 0) {476 dev_err(&interface->dev, "failed to initialize adapter\n");477 goto error_free;478 }479 480 /* and finally attach to i2c layer */481 ret = i2c_add_adapter(&dev->adapter);482 if (ret < 0)483 goto error_free;484 485 dev_dbg(&interface->dev, "connected " DRIVER_NAME "\n");486 487 return 0;488 489error_free:490 usb_set_intfdata(interface, NULL);491 diolan_u2c_free(dev);492error:493 return ret;494}495 496static void diolan_u2c_disconnect(struct usb_interface *interface)497{498 struct i2c_diolan_u2c *dev = usb_get_intfdata(interface);499 500 i2c_del_adapter(&dev->adapter);501 usb_set_intfdata(interface, NULL);502 diolan_u2c_free(dev);503 504 dev_dbg(&interface->dev, "disconnected\n");505}506 507static struct usb_driver diolan_u2c_driver = {508 .name = DRIVER_NAME,509 .probe = diolan_u2c_probe,510 .disconnect = diolan_u2c_disconnect,511 .id_table = diolan_u2c_table,512};513 514module_usb_driver(diolan_u2c_driver);515 516MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");517MODULE_DESCRIPTION(DRIVER_NAME " driver");518MODULE_LICENSE("GPL");519