drivers/media/pci/netup_unidvb/netup_unidvb_i2c.c

   1 /*
   2  * netup_unidvb_i2c.c
   3  *
   4  * Internal I2C bus driver for NetUP Universal Dual DVB-CI
   5  *
   6  * Copyright (C) 2014 NetUP Inc.
   7  * Copyright (C) 2014 Sergey Kozlov <serjk@netup.ru>
   8  * Copyright (C) 2014 Abylay Ospan <aospan@netup.ru>
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License as published by
  12  * the Free Software Foundation; either version 2 of the License, or
  13  * (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  */
  20
  21 #include <linux/module.h>
  22 #include <linux/moduleparam.h>
  23 #include <linux/init.h>
  24 #include <linux/delay.h>
  25 #include "netup_unidvb.h"
  26
  27 #define NETUP_I2C_BUS0_ADDR             0x4800
  28 #define NETUP_I2C_BUS1_ADDR             0x4840
  29 #define NETUP_I2C_TIMEOUT               1000
  30
  31 /* twi_ctrl0_stat reg bits */
  32 #define TWI_IRQEN_COMPL 0x1
  33 #define TWI_IRQEN_ANACK 0x2
  34 #define TWI_IRQEN_DNACK 0x4
  35 #define TWI_IRQ_COMPL   (TWI_IRQEN_COMPL << 8)
  36 #define TWI_IRQ_ANACK   (TWI_IRQEN_ANACK << 8)
  37 #define TWI_IRQ_DNACK   (TWI_IRQEN_DNACK << 8)
  38 #define TWI_IRQ_TX      0x800
  39 #define TWI_IRQ_RX      0x1000
  40 #define TWI_IRQEN       (TWI_IRQEN_COMPL | TWI_IRQEN_ANACK | TWI_IRQEN_DNACK)
  41 /* twi_addr_ctrl1 reg bits*/
  42 #define TWI_TRANSFER    0x100
  43 #define TWI_NOSTOP      0x200
  44 #define TWI_SOFT_RESET  0x2000
  45 /* twi_clkdiv reg value */
  46 #define TWI_CLKDIV      156
  47 /* fifo_stat_ctrl reg bits */
  48 #define FIFO_IRQEN      0x8000
  49 #define FIFO_RESET      0x4000
  50 /* FIFO size */
  51 #define FIFO_SIZE       16
  52
  53 struct netup_i2c_fifo_regs {
  54         union {
  55                 __u8    data8;
  56                 __le16  data16;
  57                 __le32  data32;
  58         };
  59         __u8            padding[4];
  60         __le16          stat_ctrl;
  61 } __packed __aligned(1);
  62
  63 struct netup_i2c_regs {
  64         __le16                          clkdiv;
  65         __le16                          twi_ctrl0_stat;
  66         __le16                          twi_addr_ctrl1;
  67         __le16                          length;
  68         __u8                            padding1[8];
  69         struct netup_i2c_fifo_regs      tx_fifo;
  70         __u8                            padding2[6];
  71         struct netup_i2c_fifo_regs      rx_fifo;
  72 } __packed __aligned(1);
  73
  74 irqreturn_t netup_i2c_interrupt(struct netup_i2c *i2c)
  75 {
  76         u16 reg, tmp;
  77         unsigned long flags;
  78         irqreturn_t iret = IRQ_HANDLED;
  79
  80         spin_lock_irqsave(&i2c->lock, flags);
  81         reg = readw(&i2c->regs->twi_ctrl0_stat);
  82         writew(reg & ~TWI_IRQEN, &i2c->regs->twi_ctrl0_stat);
  83         dev_dbg(i2c->adap.dev.parent,
  84                 "%s(): twi_ctrl0_state 0x%x\n", __func__, reg);
  85         if ((reg & TWI_IRQEN_COMPL) != 0 && (reg & TWI_IRQ_COMPL)) {
  86                 dev_dbg(i2c->adap.dev.parent,
  87                         "%s(): TWI_IRQEN_COMPL\n", __func__);
  88                 i2c->state = STATE_DONE;
  89                 goto irq_ok;
  90         }
  91         if ((reg & TWI_IRQEN_ANACK) != 0 && (reg & TWI_IRQ_ANACK)) {
  92                 dev_dbg(i2c->adap.dev.parent,
  93                         "%s(): TWI_IRQEN_ANACK\n", __func__);
  94                 i2c->state = STATE_ERROR;
  95                 goto irq_ok;
  96         }
  97         if ((reg & TWI_IRQEN_DNACK) != 0 && (reg & TWI_IRQ_DNACK)) {
  98                 dev_dbg(i2c->adap.dev.parent,
  99                         "%s(): TWI_IRQEN_DNACK\n", __func__);
 100                 i2c->state = STATE_ERROR;
 101                 goto irq_ok;
 102         }
 103         if ((reg & TWI_IRQ_RX) != 0) {
 104                 tmp = readw(&i2c->regs->rx_fifo.stat_ctrl);
 105                 writew(tmp & ~FIFO_IRQEN, &i2c->regs->rx_fifo.stat_ctrl);
 106                 i2c->state = STATE_WANT_READ;
 107                 dev_dbg(i2c->adap.dev.parent,
 108                         "%s(): want read\n", __func__);
 109                 goto irq_ok;
 110         }
 111         if ((reg & TWI_IRQ_TX) != 0) {
 112                 tmp = readw(&i2c->regs->tx_fifo.stat_ctrl);
 113                 writew(tmp & ~FIFO_IRQEN, &i2c->regs->tx_fifo.stat_ctrl);
 114                 i2c->state = STATE_WANT_WRITE;
 115                 dev_dbg(i2c->adap.dev.parent,
 116                         "%s(): want write\n", __func__);
 117                 goto irq_ok;
 118         }
 119         dev_warn(&i2c->adap.dev, "%s(): not mine interrupt\n", __func__);
 120         iret = IRQ_NONE;
 121 irq_ok:
 122         spin_unlock_irqrestore(&i2c->lock, flags);
 123         if (iret == IRQ_HANDLED)
 124                 wake_up(&i2c->wq);
 125         return iret;
 126 }
 127
 128 static void netup_i2c_reset(struct netup_i2c *i2c)
 129 {
 130         dev_dbg(i2c->adap.dev.parent, "%s()\n", __func__);
 131         i2c->state = STATE_DONE;
 132         writew(TWI_SOFT_RESET, &i2c->regs->twi_addr_ctrl1);
 133         writew(TWI_CLKDIV, &i2c->regs->clkdiv);
 134         writew(FIFO_RESET, &i2c->regs->tx_fifo.stat_ctrl);
 135         writew(FIFO_RESET, &i2c->regs->rx_fifo.stat_ctrl);
 136         writew(0x800, &i2c->regs->tx_fifo.stat_ctrl);
 137         writew(0x800, &i2c->regs->rx_fifo.stat_ctrl);
 138 }
 139
 140 static void netup_i2c_fifo_tx(struct netup_i2c *i2c)
 141 {
 142         u8 data;
 143         u32 fifo_space = FIFO_SIZE -
 144                 (readw(&i2c->regs->tx_fifo.stat_ctrl) & 0x3f);
 145         u32 msg_length = i2c->msg->len - i2c->xmit_size;
 146
 147         msg_length = (msg_length < fifo_space ? msg_length : fifo_space);
 148         while (msg_length--) {
 149                 data = i2c->msg->buf[i2c->xmit_size++];
 150                 writeb(data, &i2c->regs->tx_fifo.data8);
 151                 dev_dbg(i2c->adap.dev.parent,
 152                         "%s(): write 0x%02x\n", __func__, data);
 153         }
 154         if (i2c->xmit_size < i2c->msg->len) {
 155                 dev_dbg(i2c->adap.dev.parent,
 156                         "%s(): TX IRQ enabled\n", __func__);
 157                 writew(readw(&i2c->regs->tx_fifo.stat_ctrl) | FIFO_IRQEN,
 158                         &i2c->regs->tx_fifo.stat_ctrl);
 159         }
 160 }
 161
 162 static void netup_i2c_fifo_rx(struct netup_i2c *i2c)
 163 {
 164         u8 data;
 165         u32 fifo_size = readw(&i2c->regs->rx_fifo.stat_ctrl) & 0x3f;
 166
 167         dev_dbg(i2c->adap.dev.parent,
 168                 "%s(): RX fifo size %d\n", __func__, fifo_size);
 169         while (fifo_size--) {
 170                 data = readb(&i2c->regs->rx_fifo.data8);
 171                 if ((i2c->msg->flags & I2C_M_RD) != 0 &&
 172                                         i2c->xmit_size < i2c->msg->len) {
 173                         i2c->msg->buf[i2c->xmit_size++] = data;
 174                         dev_dbg(i2c->adap.dev.parent,
 175                                 "%s(): read 0x%02x\n", __func__, data);
 176                 }
 177         }
 178         if (i2c->xmit_size < i2c->msg->len) {
 179                 dev_dbg(i2c->adap.dev.parent,
 180                         "%s(): RX IRQ enabled\n", __func__);
 181                 writew(readw(&i2c->regs->rx_fifo.stat_ctrl) | FIFO_IRQEN,
 182                         &i2c->regs->rx_fifo.stat_ctrl);
 183         }
 184 }
 185
 186 static void netup_i2c_start_xfer(struct netup_i2c *i2c)
 187 {
 188         u16 rdflag = ((i2c->msg->flags & I2C_M_RD) ? 1 : 0);
 189         u16 reg = readw(&i2c->regs->twi_ctrl0_stat);
 190
 191         writew(TWI_IRQEN | reg, &i2c->regs->twi_ctrl0_stat);
 192         writew(i2c->msg->len, &i2c->regs->length);
 193         writew(TWI_TRANSFER | (i2c->msg->addr << 1) | rdflag,
 194                 &i2c->regs->twi_addr_ctrl1);
 195         dev_dbg(i2c->adap.dev.parent,
 196                 "%s(): length %d twi_addr_ctrl1 0x%x twi_ctrl0_stat 0x%x\n",
 197                 __func__, readw(&i2c->regs->length),
 198                 readw(&i2c->regs->twi_addr_ctrl1),
 199                 readw(&i2c->regs->twi_ctrl0_stat));
 200         i2c->state = STATE_WAIT;
 201         i2c->xmit_size = 0;
 202         if (!rdflag)
 203                 netup_i2c_fifo_tx(i2c);
 204         else
 205                 writew(FIFO_IRQEN | readw(&i2c->regs->rx_fifo.stat_ctrl),
 206                         &i2c->regs->rx_fifo.stat_ctrl);
 207 }
 208
 209 static int netup_i2c_xfer(struct i2c_adapter *adap,
 210                           struct i2c_msg *msgs, int num)
 211 {
 212         unsigned long flags;
 213         int i, trans_done, res = num;
 214         struct netup_i2c *i2c = i2c_get_adapdata(adap);
 215         u16 reg;
 216
 217         if (num <= 0) {
 218                 dev_dbg(i2c->adap.dev.parent,
 219                         "%s(): num == %d\n", __func__, num);
 220                 return -EINVAL;
 221         }
 222         spin_lock_irqsave(&i2c->lock, flags);
 223         if (i2c->state != STATE_DONE) {
 224                 dev_dbg(i2c->adap.dev.parent,
 225                         "%s(): i2c->state == %d, resetting I2C\n",
 226                         __func__, i2c->state);
 227                 netup_i2c_reset(i2c);
 228         }
 229         dev_dbg(i2c->adap.dev.parent, "%s() num %d\n", __func__, num);
 230         for (i = 0; i < num; i++) {
 231                 i2c->msg = &msgs[i];
 232                 netup_i2c_start_xfer(i2c);
 233                 trans_done = 0;
 234                 while (!trans_done) {
 235                         spin_unlock_irqrestore(&i2c->lock, flags);
 236                         if (wait_event_timeout(i2c->wq,
 237                                         i2c->state != STATE_WAIT,
 238                                         msecs_to_jiffies(NETUP_I2C_TIMEOUT))) {
 239                                 spin_lock_irqsave(&i2c->lock, flags);
 240                                 switch (i2c->state) {
 241                                 case STATE_WANT_READ:
 242                                         netup_i2c_fifo_rx(i2c);
 243                                         break;
 244                                 case STATE_WANT_WRITE:
 245                                         netup_i2c_fifo_tx(i2c);
 246                                         break;
 247                                 case STATE_DONE:
 248                                         if ((i2c->msg->flags & I2C_M_RD) != 0 &&
 249                                                 i2c->xmit_size != i2c->msg->len)
 250                                                 netup_i2c_fifo_rx(i2c);
 251                                         dev_dbg(i2c->adap.dev.parent,
 252                                                 "%s(): msg %d OK\n",
 253                                                 __func__, i);
 254                                         trans_done = 1;
 255                                         break;
 256                                 case STATE_ERROR:
 257                                         res = -EIO;
 258                                         dev_dbg(i2c->adap.dev.parent,
 259                                                 "%s(): error state\n",
 260                                                 __func__);
 261                                         goto done;
 262                                 default:
 263                                         dev_dbg(i2c->adap.dev.parent,
 264                                                 "%s(): invalid state %d\n",
 265                                                 __func__, i2c->state);
 266                                         res = -EINVAL;
 267                                         goto done;
 268                                 }
 269                                 if (!trans_done) {
 270                                         i2c->state = STATE_WAIT;
 271                                         reg = readw(
 272                                                 &i2c->regs->twi_ctrl0_stat);
 273                                         writew(TWI_IRQEN | reg,
 274                                                 &i2c->regs->twi_ctrl0_stat);
 275                                 }
 276                                 spin_unlock_irqrestore(&i2c->lock, flags);
 277                         } else {
 278                                 spin_lock_irqsave(&i2c->lock, flags);
 279                                 dev_dbg(i2c->adap.dev.parent,
 280                                         "%s(): wait timeout\n", __func__);
 281                                 res = -ETIMEDOUT;
 282                                 goto done;
 283                         }
 284                         spin_lock_irqsave(&i2c->lock, flags);
 285                 }
 286         }
 287 done:
 288         spin_unlock_irqrestore(&i2c->lock, flags);
 289         dev_dbg(i2c->adap.dev.parent, "%s(): result %d\n", __func__, res);
 290         return res;
 291 }
 292
 293 static u32 netup_i2c_func(struct i2c_adapter *adap)
 294 {
 295         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
 296 }
 297
 298 static const struct i2c_algorithm netup_i2c_algorithm = {
 299         .master_xfer    = netup_i2c_xfer,
 300         .functionality  = netup_i2c_func,
 301 };
 302
 303 static const struct i2c_adapter netup_i2c_adapter = {
 304         .owner          = THIS_MODULE,
 305         .name           = NETUP_UNIDVB_NAME,
 306         .class          = I2C_CLASS_HWMON | I2C_CLASS_SPD,
 307         .algo           = &netup_i2c_algorithm,
 308 };
 309
 310 static int netup_i2c_init(struct netup_unidvb_dev *ndev, int bus_num)
 311 {
 312         int ret;
 313         struct netup_i2c *i2c;
 314
 315         if (bus_num < 0 || bus_num > 1) {
 316                 dev_err(&ndev->pci_dev->dev,
 317                         "%s(): invalid bus_num %d\n", __func__, bus_num);
 318                 return -EINVAL;
 319         }
 320         i2c = &ndev->i2c[bus_num];
 321         spin_lock_init(&i2c->lock);
 322         init_waitqueue_head(&i2c->wq);
 323         i2c->regs = (struct netup_i2c_regs __iomem *)(ndev->bmmio0 +
 324                 (bus_num == 0 ? NETUP_I2C_BUS0_ADDR : NETUP_I2C_BUS1_ADDR));
 325         netup_i2c_reset(i2c);
 326         i2c->adap = netup_i2c_adapter;
 327         i2c->adap.dev.parent = &ndev->pci_dev->dev;
 328         i2c_set_adapdata(&i2c->adap, i2c);
 329         ret = i2c_add_adapter(&i2c->adap);
 330         if (ret)
 331                 return ret;
 332         dev_info(&ndev->pci_dev->dev,
 333                 "%s(): registered I2C bus %d at 0x%x\n",
 334                 __func__,
 335                 bus_num, (bus_num == 0 ?
 336                         NETUP_I2C_BUS0_ADDR :
 337                         NETUP_I2C_BUS1_ADDR));
 338         return 0;
 339 }
 340
 341 static void netup_i2c_remove(struct netup_unidvb_dev *ndev, int bus_num)
 342 {
 343         struct netup_i2c *i2c;
 344
 345         if (bus_num < 0 || bus_num > 1) {
 346                 dev_err(&ndev->pci_dev->dev,
 347                         "%s(): invalid bus number %d\n", __func__, bus_num);
 348                 return;
 349         }
 350         i2c = &ndev->i2c[bus_num];
 351         netup_i2c_reset(i2c);
 352         /* remove adapter */
 353         i2c_del_adapter(&i2c->adap);
 354         dev_info(&ndev->pci_dev->dev,
 355                 "netup_i2c_remove: unregistered I2C bus %d\n", bus_num);
 356 }
 357
 358 int netup_i2c_register(struct netup_unidvb_dev *ndev)
 359 {
 360         int ret;
 361
 362         ret = netup_i2c_init(ndev, 0);
 363         if (ret)
 364                 return ret;
 365         ret = netup_i2c_init(ndev, 1);
 366         if (ret) {
 367                 netup_i2c_remove(ndev, 0);
 368                 return ret;
 369         }
 370         return 0;
 371 }
 372
 373 void netup_i2c_unregister(struct netup_unidvb_dev *ndev)
 374 {
 375         netup_i2c_remove(ndev, 0);
 376         netup_i2c_remove(ndev, 1);
 377 }
 378