drivers/i2c/rk_i2c.c

   1 /*
   2  * (C) Copyright 2015 Google, Inc
   3  *
   4  * (C) Copyright 2008-2014 Rockchip Electronics
   5  * Peter, Software Engineering, <superpeter.cai@gmail.com>.
   6  *
   7  * SPDX-License-Identifier:     GPL-2.0+
   8  */
   9
  10 #include <common.h>
  11 #include <clk.h>
  12 #include <dm.h>
  13 #include <errno.h>
  14 #include <i2c.h>
  15 #include <asm/io.h>
  16 #include <asm/arch/clock.h>
  17 #include <asm/arch/i2c.h>
  18 #include <asm/arch/periph.h>
  19 #include <dm/pinctrl.h>
  20 #include <linux/sizes.h>
  21
  22 DECLARE_GLOBAL_DATA_PTR;
  23
  24 /* i2c timerout */
  25 #define I2C_TIMEOUT_MS          100
  26 #define I2C_RETRY_COUNT         3
  27
  28 /* rk i2c fifo max transfer bytes */
  29 #define RK_I2C_FIFO_SIZE        32
  30
  31 struct rk_i2c {
  32         struct udevice *clk;
  33         struct i2c_regs *regs;
  34         unsigned int speed;
  35         int clk_id;
  36 };
  37
  38 static inline void rk_i2c_get_div(int div, int *divh, int *divl)
  39 {
  40         *divl = div / 2;
  41         if (div % 2 == 0)
  42                 *divh = div / 2;
  43         else
  44                 *divh = DIV_ROUND_UP(div, 2);
  45 }
  46
  47 /*
  48  * SCL Divisor = 8 * (CLKDIVL+1 + CLKDIVH+1)
  49  * SCL = PCLK / SCLK Divisor
  50  * i2c_rate = PCLK
  51  */
  52 static void rk_i2c_set_clk(struct rk_i2c *i2c, uint32_t scl_rate)
  53 {
  54         uint32_t i2c_rate;
  55         int div, divl, divh;
  56
  57         /* First get i2c rate from pclk */
  58         i2c_rate = clk_get_periph_rate(i2c->clk, i2c->clk_id);
  59
  60         div = DIV_ROUND_UP(i2c_rate, scl_rate * 8) - 2;
  61         divh = 0;
  62         divl = 0;
  63         if (div >= 0)
  64                 rk_i2c_get_div(div, &divh, &divl);
  65         writel(I2C_CLKDIV_VAL(divl, divh), &i2c->regs->clkdiv);
  66
  67         debug("rk_i2c_set_clk: i2c rate = %d, scl rate = %d\n", i2c_rate,
  68               scl_rate);
  69         debug("set i2c clk div = %d, divh = %d, divl = %d\n", div, divh, divl);
  70         debug("set clk(I2C_CLKDIV: 0x%08x)\n", readl(&i2c->regs->clkdiv));
  71 }
  72
  73 static void rk_i2c_show_regs(struct i2c_regs *regs)
  74 {
  75 #ifdef DEBUG
  76         uint i;
  77
  78         debug("i2c_con: 0x%08x\n", readl(&regs->con));
  79         debug("i2c_clkdiv: 0x%08x\n", readl(&regs->clkdiv));
  80         debug("i2c_mrxaddr: 0x%08x\n", readl(&regs->mrxaddr));
  81         debug("i2c_mrxraddR: 0x%08x\n", readl(&regs->mrxraddr));
  82         debug("i2c_mtxcnt: 0x%08x\n", readl(&regs->mtxcnt));
  83         debug("i2c_mrxcnt: 0x%08x\n", readl(&regs->mrxcnt));
  84         debug("i2c_ien: 0x%08x\n", readl(&regs->ien));
  85         debug("i2c_ipd: 0x%08x\n", readl(&regs->ipd));
  86         debug("i2c_fcnt: 0x%08x\n", readl(&regs->fcnt));
  87         for (i = 0; i < 8; i++)
  88                 debug("i2c_txdata%d: 0x%08x\n", i, readl(&regs->txdata[i]));
  89         for (i = 0; i < 8; i++)
  90                 debug("i2c_rxdata%d: 0x%08x\n", i, readl(&regs->rxdata[i]));
  91 #endif
  92 }
  93
  94 static int rk_i2c_send_start_bit(struct rk_i2c *i2c)
  95 {
  96         struct i2c_regs *regs = i2c->regs;
  97         ulong start;
  98
  99         debug("I2c Send Start bit.\n");
 100         writel(I2C_IPD_ALL_CLEAN, &regs->ipd);
 101
 102         writel(I2C_CON_EN | I2C_CON_START, &regs->con);
 103         writel(I2C_STARTIEN, &regs->ien);
 104
 105         start = get_timer(0);
 106         while (1) {
 107                 if (readl(&regs->ipd) & I2C_STARTIPD) {
 108                         writel(I2C_STARTIPD, &regs->ipd);
 109                         break;
 110                 }
 111                 if (get_timer(start) > I2C_TIMEOUT_MS) {
 112                         debug("I2C Send Start Bit Timeout\n");
 113                         rk_i2c_show_regs(regs);
 114                         return -ETIMEDOUT;
 115                 }
 116                 udelay(1);
 117         }
 118
 119         return 0;
 120 }
 121
 122 static int rk_i2c_send_stop_bit(struct rk_i2c *i2c)
 123 {
 124         struct i2c_regs *regs = i2c->regs;
 125         ulong start;
 126
 127         debug("I2c Send Stop bit.\n");
 128         writel(I2C_IPD_ALL_CLEAN, &regs->ipd);
 129
 130         writel(I2C_CON_EN | I2C_CON_STOP, &regs->con);
 131         writel(I2C_CON_STOP, &regs->ien);
 132
 133         start = get_timer(0);
 134         while (1) {
 135                 if (readl(&regs->ipd) & I2C_STOPIPD) {
 136                         writel(I2C_STOPIPD, &regs->ipd);
 137                         break;
 138                 }
 139                 if (get_timer(start) > I2C_TIMEOUT_MS) {
 140                         debug("I2C Send Start Bit Timeout\n");
 141                         rk_i2c_show_regs(regs);
 142                         return -ETIMEDOUT;
 143                 }
 144                 udelay(1);
 145         }
 146
 147         return 0;
 148 }
 149
 150 static inline void rk_i2c_disable(struct rk_i2c *i2c)
 151 {
 152         writel(0, &i2c->regs->con);
 153 }
 154
 155 static int rk_i2c_read(struct rk_i2c *i2c, uchar chip, uint reg, uint r_len,
 156                        uchar *buf, uint b_len)
 157 {
 158         struct i2c_regs *regs = i2c->regs;
 159         uchar *pbuf = buf;
 160         uint bytes_remain_len = b_len;
 161         uint bytes_xferred = 0;
 162         uint words_xferred = 0;
 163         ulong start;
 164         uint con = 0;
 165         uint rxdata;
 166         uint i, j;
 167         int err;
 168
 169         debug("rk_i2c_read: chip = %d, reg = %d, r_len = %d, b_len = %d\n",
 170               chip, reg, r_len, b_len);
 171
 172         err = rk_i2c_send_start_bit(i2c);
 173         if (err)
 174                 return err;
 175
 176         writel(I2C_MRXADDR_SET(1, chip << 1 | 1), &regs->mrxaddr);
 177         if (r_len == 0) {
 178                 writel(0, &regs->mrxraddr);
 179         } else if (r_len < 4) {
 180                 writel(I2C_MRXRADDR_SET(r_len, reg), &regs->mrxraddr);
 181         } else {
 182                 debug("I2C Read: addr len %d not supported\n", r_len);
 183                 return -EIO;
 184         }
 185
 186         while (bytes_remain_len) {
 187                 if (bytes_remain_len > RK_I2C_FIFO_SIZE) {
 188                         con = I2C_CON_EN | I2C_CON_MOD(I2C_MODE_TRX);
 189                         bytes_xferred = 32;
 190                 } else {
 191                         con = I2C_CON_EN | I2C_CON_MOD(I2C_MODE_TRX) |
 192                                 I2C_CON_LASTACK;
 193                         bytes_xferred = bytes_remain_len;
 194                 }
 195                 words_xferred = DIV_ROUND_UP(bytes_xferred, 4);
 196
 197                 writel(con, &regs->con);
 198                 writel(bytes_xferred, &regs->mrxcnt);
 199                 writel(I2C_MBRFIEN | I2C_NAKRCVIEN, &regs->ien);
 200
 201                 start = get_timer(0);
 202                 while (1) {
 203                         if (readl(&regs->ipd) & I2C_NAKRCVIPD) {
 204                                 writel(I2C_NAKRCVIPD, &regs->ipd);
 205                                 err = -EREMOTEIO;
 206                         }
 207                         if (readl(&regs->ipd) & I2C_MBRFIPD) {
 208                                 writel(I2C_MBRFIPD, &regs->ipd);
 209                                 break;
 210                         }
 211                         if (get_timer(start) > I2C_TIMEOUT_MS) {
 212                                 debug("I2C Read Data Timeout\n");
 213                                 err =  -ETIMEDOUT;
 214                                 rk_i2c_show_regs(regs);
 215                                 goto i2c_exit;
 216                         }
 217                         udelay(1);
 218                 }
 219
 220                 for (i = 0; i < words_xferred; i++) {
 221                         rxdata = readl(&regs->rxdata[i]);
 222                         debug("I2c Read RXDATA[%d] = 0x%x\n", i, rxdata);
 223                         for (j = 0; j < 4; j++) {
 224                                 if ((i * 4 + j) == bytes_xferred)
 225                                         break;
 226                                 *pbuf++ = (rxdata >> (j * 8)) & 0xff;
 227                         }
 228                 }
 229
 230                 bytes_remain_len -= bytes_xferred;
 231                 debug("I2C Read bytes_remain_len %d\n", bytes_remain_len);
 232         }
 233
 234 i2c_exit:
 235         rk_i2c_send_stop_bit(i2c);
 236         rk_i2c_disable(i2c);
 237
 238         return err;
 239 }
 240
 241 static int rk_i2c_write(struct rk_i2c *i2c, uchar chip, uint reg, uint r_len,
 242                         uchar *buf, uint b_len)
 243 {
 244         struct i2c_regs *regs = i2c->regs;
 245         int err;
 246         uchar *pbuf = buf;
 247         uint bytes_remain_len = b_len + r_len + 1;
 248         uint bytes_xferred = 0;
 249         uint words_xferred = 0;
 250         ulong start;
 251         uint txdata;
 252         uint i, j;
 253
 254         debug("rk_i2c_write: chip = %d, reg = %d, r_len = %d, b_len = %d\n",
 255               chip, reg, r_len, b_len);
 256         err = rk_i2c_send_start_bit(i2c);
 257         if (err)
 258                 return err;
 259
 260         while (bytes_remain_len) {
 261                 if (bytes_remain_len > RK_I2C_FIFO_SIZE)
 262                         bytes_xferred = 32;
 263                 else
 264                         bytes_xferred = bytes_remain_len;
 265                 words_xferred = DIV_ROUND_UP(bytes_xferred, 4);
 266
 267                 for (i = 0; i < words_xferred; i++) {
 268                         txdata = 0;
 269                         for (j = 0; j < 4; j++) {
 270                                 if ((i * 4 + j) == bytes_xferred)
 271                                         break;
 272
 273                                 if (i == 0 && j == 0) {
 274                                         txdata |= (chip << 1);
 275                                 } else if (i == 0 && j <= r_len) {
 276                                         txdata |= (reg &
 277                                                 (0xff << ((j - 1) * 8))) << 8;
 278                                 } else {
 279                                         txdata |= (*pbuf++)<<(j * 8);
 280                                 }
 281                                 writel(txdata, &regs->txdata[i]);
 282                         }
 283                         debug("I2c Write TXDATA[%d] = 0x%x\n", i, txdata);
 284                 }
 285
 286                 writel(I2C_CON_EN | I2C_CON_MOD(I2C_MODE_TX), &regs->con);
 287                 writel(bytes_xferred, &regs->mtxcnt);
 288                 writel(I2C_MBTFIEN | I2C_NAKRCVIEN, &regs->ien);
 289
 290                 start = get_timer(0);
 291                 while (1) {
 292                         if (readl(&regs->ipd) & I2C_NAKRCVIPD) {
 293                                 writel(I2C_NAKRCVIPD, &regs->ipd);
 294                                 err = -EREMOTEIO;
 295                         }
 296                         if (readl(&regs->ipd) & I2C_MBTFIPD) {
 297                                 writel(I2C_MBTFIPD, &regs->ipd);
 298                                 break;
 299                         }
 300                         if (get_timer(start) > I2C_TIMEOUT_MS) {
 301                                 debug("I2C Write Data Timeout\n");
 302                                 err =  -ETIMEDOUT;
 303                                 rk_i2c_show_regs(regs);
 304                                 goto i2c_exit;
 305                         }
 306                         udelay(1);
 307                 }
 308
 309                 bytes_remain_len -= bytes_xferred;
 310                 debug("I2C Write bytes_remain_len %d\n", bytes_remain_len);
 311         }
 312
 313 i2c_exit:
 314         rk_i2c_send_stop_bit(i2c);
 315         rk_i2c_disable(i2c);
 316
 317         return err;
 318 }
 319
 320 static int rockchip_i2c_xfer(struct udevice *bus, struct i2c_msg *msg,
 321                              int nmsgs)
 322 {
 323         struct rk_i2c *i2c = dev_get_priv(bus);
 324         int ret;
 325
 326         debug("i2c_xfer: %d messages\n", nmsgs);
 327         for (; nmsgs > 0; nmsgs--, msg++) {
 328                 debug("i2c_xfer: chip=0x%x, len=0x%x\n", msg->addr, msg->len);
 329                 if (msg->flags & I2C_M_RD) {
 330                         ret = rk_i2c_read(i2c, msg->addr, 0, 0, msg->buf,
 331                                           msg->len);
 332                 } else {
 333                         ret = rk_i2c_write(i2c, msg->addr, 0, 0, msg->buf,
 334                                            msg->len);
 335                 }
 336                 if (ret) {
 337                         debug("i2c_write: error sending\n");
 338                         return -EREMOTEIO;
 339                 }
 340         }
 341
 342         return 0;
 343 }
 344
 345 int rockchip_i2c_set_bus_speed(struct udevice *bus, unsigned int speed)
 346 {
 347         struct rk_i2c *i2c = dev_get_priv(bus);
 348
 349         rk_i2c_set_clk(i2c, speed);
 350
 351         return 0;
 352 }
 353
 354 static int rockchip_i2c_ofdata_to_platdata(struct udevice *bus)
 355 {
 356         struct rk_i2c *priv = dev_get_priv(bus);
 357         int ret;
 358
 359         ret = clk_get_by_index(bus, 0, &priv->clk);
 360         if (ret < 0) {
 361                 debug("%s: Could not get clock for %s: %d\n", __func__,
 362                       bus->name, ret);
 363                 return ret;
 364         }
 365         priv->clk_id = ret;
 366
 367         return 0;
 368 }
 369
 370 static int rockchip_i2c_probe(struct udevice *bus)
 371 {
 372         struct rk_i2c *priv = dev_get_priv(bus);
 373
 374         priv->regs = (void *)dev_get_addr(bus);
 375
 376         return 0;
 377 }
 378
 379 static const struct dm_i2c_ops rockchip_i2c_ops = {
 380         .xfer           = rockchip_i2c_xfer,
 381         .set_bus_speed  = rockchip_i2c_set_bus_speed,
 382 };
 383
 384 static const struct udevice_id rockchip_i2c_ids[] = {
 385         { .compatible = "rockchip,rk3288-i2c" },
 386         { }
 387 };
 388
 389 U_BOOT_DRIVER(i2c_rockchip) = {
 390         .name   = "i2c_rockchip",
 391         .id     = UCLASS_I2C,
 392         .of_match = rockchip_i2c_ids,
 393         .ofdata_to_platdata = rockchip_i2c_ofdata_to_platdata,
 394         .probe  = rockchip_i2c_probe,
 395         .priv_auto_alloc_size = sizeof(struct rk_i2c),
 396         .ops    = &rockchip_i2c_ops,
 397 };