drivers/i2c/lpc32xx_i2c.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * LPC32xx I2C interface driver
   4  *
   5  * (C) Copyright 2014-2015  DENX Software Engineering GmbH
   6  * Written-by: Albert ARIBAUD - 3ADEV <albert.aribaud@3adev.fr>
   7  */
   8
   9 #include <common.h>
  10 #include <asm/io.h>
  11 #include <i2c.h>
  12 #include <linux/errno.h>
  13 #include <asm/arch/clk.h>
  14 #include <asm/arch/i2c.h>
  15 #include <dm.h>
  16 #include <mapmem.h>
  17
  18 /*
  19  * Provide default speed and slave if target did not
  20  */
  21
  22 #if !defined(CONFIG_SYS_I2C_LPC32XX_SPEED)
  23 #define CONFIG_SYS_I2C_LPC32XX_SPEED 350000
  24 #endif
  25
  26 #if !defined(CONFIG_SYS_I2C_LPC32XX_SLAVE)
  27 #define CONFIG_SYS_I2C_LPC32XX_SLAVE 0
  28 #endif
  29
  30 /* TX register fields */
  31 #define LPC32XX_I2C_TX_START            0x00000100
  32 #define LPC32XX_I2C_TX_STOP             0x00000200
  33
  34 /* Control register values */
  35 #define LPC32XX_I2C_SOFT_RESET          0x00000100
  36
  37 /* Status register values */
  38 #define LPC32XX_I2C_STAT_TFF            0x00000400
  39 #define LPC32XX_I2C_STAT_RFE            0x00000200
  40 #define LPC32XX_I2C_STAT_DRMI           0x00000008
  41 #define LPC32XX_I2C_STAT_NAI            0x00000004
  42 #define LPC32XX_I2C_STAT_TDI            0x00000001
  43
  44 #ifndef CONFIG_DM_I2C
  45 static struct lpc32xx_i2c_base *lpc32xx_i2c[] = {
  46         (struct lpc32xx_i2c_base *)I2C1_BASE,
  47         (struct lpc32xx_i2c_base *)I2C2_BASE,
  48         (struct lpc32xx_i2c_base *)(USB_BASE + 0x300)
  49 };
  50 #endif
  51
  52 /* Set I2C bus speed */
  53 static unsigned int __i2c_set_bus_speed(struct lpc32xx_i2c_base *base,
  54                                         unsigned int speed, unsigned int chip)
  55 {
  56         int half_period;
  57
  58         if (speed == 0)
  59                 return -EINVAL;
  60
  61         /* OTG I2C clock source and CLK registers are different */
  62         if (chip == 2) {
  63                 half_period = (get_periph_clk_rate() / speed) / 2;
  64                 if (half_period > 0xFF)
  65                         return -EINVAL;
  66         } else {
  67                 half_period = (get_hclk_clk_rate() / speed) / 2;
  68                 if (half_period > 0x3FF)
  69                         return -EINVAL;
  70         }
  71
  72         writel(half_period, &base->clk_hi);
  73         writel(half_period, &base->clk_lo);
  74         return 0;
  75 }
  76
  77 /* I2C init called by cmd_i2c when doing 'i2c reset'. */
  78 static void __i2c_init(struct lpc32xx_i2c_base *base,
  79                        int requested_speed, int slaveadd, unsigned int chip)
  80 {
  81         /* soft reset (auto-clears) */
  82         writel(LPC32XX_I2C_SOFT_RESET, &base->ctrl);
  83         /* set HI and LO periods for half of the default speed */
  84         __i2c_set_bus_speed(base, requested_speed, chip);
  85 }
  86
  87 /* I2C probe called by cmd_i2c when doing 'i2c probe'. */
  88 static int __i2c_probe_chip(struct lpc32xx_i2c_base *base, u8 dev)
  89 {
  90         int stat;
  91
  92         /* Soft-reset the controller */
  93         writel(LPC32XX_I2C_SOFT_RESET, &base->ctrl);
  94         while (readl(&base->ctrl) & LPC32XX_I2C_SOFT_RESET)
  95                 ;
  96         /* Addre slave for write with start before and stop after */
  97         writel((dev<<1) | LPC32XX_I2C_TX_START | LPC32XX_I2C_TX_STOP,
  98                &base->tx);
  99         /* wait for end of transation */
 100         while (!((stat = readl(&base->stat)) & LPC32XX_I2C_STAT_TDI))
 101                 ;
 102         /* was there no acknowledge? */
 103         return (stat & LPC32XX_I2C_STAT_NAI) ? -1 : 0;
 104 }
 105
 106 /*
 107  * I2C read called by cmd_i2c when doing 'i2c read' and by cmd_eeprom.c
 108  * Begin write, send address byte(s), begin read, receive data bytes, end.
 109  */
 110 static int __i2c_read(struct lpc32xx_i2c_base *base, u8 dev, uint addr,
 111                       int alen, u8 *data, int length)
 112 {
 113         int stat, wlen;
 114
 115         /* Soft-reset the controller */
 116         writel(LPC32XX_I2C_SOFT_RESET, &base->ctrl);
 117         while (readl(&base->ctrl) & LPC32XX_I2C_SOFT_RESET)
 118                 ;
 119         /* do we need to write an address at all? */
 120         if (alen) {
 121                 /* Address slave in write mode */
 122                 writel((dev<<1) | LPC32XX_I2C_TX_START, &base->tx);
 123                 /* write address bytes */
 124                 while (alen--) {
 125                         /* compute address byte + stop for the last one */
 126                         int a = (addr >> (8 * alen)) & 0xff;
 127                         if (!alen)
 128                                 a |= LPC32XX_I2C_TX_STOP;
 129                         /* Send address byte */
 130                         writel(a, &base->tx);
 131                 }
 132                 /* wait for end of transation */
 133                 while (!((stat = readl(&base->stat)) & LPC32XX_I2C_STAT_TDI))
 134                         ;
 135                 /* clear end-of-transaction flag */
 136                 writel(1, &base->stat);
 137         }
 138         /* do we have to read data at all? */
 139         if (length) {
 140                 /* Address slave in read mode */
 141                 writel(1 | (dev<<1) | LPC32XX_I2C_TX_START, &base->tx);
 142                 wlen = length;
 143                 /* get data */
 144                 while (length | wlen) {
 145                         /* read status for TFF and RFE */
 146                         stat = readl(&base->stat);
 147                         /* must we, can we write a trigger byte? */
 148                         if ((wlen > 0)
 149                            & (!(stat & LPC32XX_I2C_STAT_TFF))) {
 150                                 wlen--;
 151                                 /* write trigger byte + stop if last */
 152                                 writel(wlen ? 0 :
 153                                 LPC32XX_I2C_TX_STOP, &base->tx);
 154                         }
 155                         /* must we, can we read a data byte? */
 156                         if ((length > 0)
 157                            & (!(stat & LPC32XX_I2C_STAT_RFE))) {
 158                                 length--;
 159                                 /* read byte */
 160                                 *(data++) = readl(&base->rx);
 161                         }
 162                 }
 163                 /* wait for end of transation */
 164                 while (!((stat = readl(&base->stat)) & LPC32XX_I2C_STAT_TDI))
 165                         ;
 166                 /* clear end-of-transaction flag */
 167                 writel(1, &base->stat);
 168         }
 169         /* success */
 170         return 0;
 171 }
 172
 173 /*
 174  * I2C write called by cmd_i2c when doing 'i2c write' and by cmd_eeprom.c
 175  * Begin write, send address byte(s), send data bytes, end.
 176  */
 177 static int __i2c_write(struct lpc32xx_i2c_base *base, u8 dev, uint addr,
 178                        int alen, u8 *data, int length)
 179 {
 180         int stat;
 181
 182         /* Soft-reset the controller */
 183         writel(LPC32XX_I2C_SOFT_RESET, &base->ctrl);
 184         while (readl(&base->ctrl) & LPC32XX_I2C_SOFT_RESET)
 185                 ;
 186         /* do we need to write anything at all? */
 187         if (alen | length)
 188                 /* Address slave in write mode */
 189                 writel((dev<<1) | LPC32XX_I2C_TX_START, &base->tx);
 190         else
 191                 return 0;
 192         /* write address bytes */
 193         while (alen) {
 194                 /* wait for transmit fifo not full */
 195                 stat = readl(&base->stat);
 196                 if (!(stat & LPC32XX_I2C_STAT_TFF)) {
 197                         alen--;
 198                         int a = (addr >> (8 * alen)) & 0xff;
 199                         if (!(alen | length))
 200                                 a |= LPC32XX_I2C_TX_STOP;
 201                         /* Send address byte */
 202                         writel(a, &base->tx);
 203                 }
 204         }
 205         while (length) {
 206                 /* wait for transmit fifo not full */
 207                 stat = readl(&base->stat);
 208                 if (!(stat & LPC32XX_I2C_STAT_TFF)) {
 209                         /* compute data byte, add stop if length==0 */
 210                         length--;
 211                         int d = *(data++);
 212                         if (!length)
 213                                 d |= LPC32XX_I2C_TX_STOP;
 214                         /* Send data byte */
 215                         writel(d, &base->tx);
 216                 }
 217         }
 218         /* wait for end of transation */
 219         while (!((stat = readl(&base->stat)) & LPC32XX_I2C_STAT_TDI))
 220                 ;
 221         /* clear end-of-transaction flag */
 222         writel(1, &base->stat);
 223         return 0;
 224 }
 225
 226 #ifndef CONFIG_DM_I2C
 227 static void lpc32xx_i2c_init(struct i2c_adapter *adap,
 228                              int requested_speed, int slaveadd)
 229 {
 230         __i2c_init(lpc32xx_i2c[adap->hwadapnr], requested_speed, slaveadd,
 231                    adap->hwadapnr);
 232 }
 233
 234 static int lpc32xx_i2c_probe_chip(struct i2c_adapter *adap, u8 dev)
 235 {
 236         return __i2c_probe_chip(lpc32xx_i2c[adap->hwadapnr], dev);
 237 }
 238
 239 static int lpc32xx_i2c_read(struct i2c_adapter *adap, u8 dev, uint addr,
 240                             int alen, u8 *data, int length)
 241 {
 242         return __i2c_read(lpc32xx_i2c[adap->hwadapnr], dev, addr,
 243                          alen, data, length);
 244 }
 245
 246 static int lpc32xx_i2c_write(struct i2c_adapter *adap, u8 dev, uint addr,
 247                              int alen, u8 *data, int length)
 248 {
 249         return __i2c_write(lpc32xx_i2c[adap->hwadapnr], dev, addr,
 250                           alen, data, length);
 251 }
 252
 253 static unsigned int lpc32xx_i2c_set_bus_speed(struct i2c_adapter *adap,
 254                                               unsigned int speed)
 255 {
 256         return __i2c_set_bus_speed(lpc32xx_i2c[adap->hwadapnr], speed,
 257                                   adap->hwadapnr);
 258 }
 259
 260 U_BOOT_I2C_ADAP_COMPLETE(lpc32xx_0, lpc32xx_i2c_init, lpc32xx_i2c_probe_chip,
 261                          lpc32xx_i2c_read, lpc32xx_i2c_write,
 262                          lpc32xx_i2c_set_bus_speed,
 263                          CONFIG_SYS_I2C_LPC32XX_SPEED,
 264                          CONFIG_SYS_I2C_LPC32XX_SLAVE,
 265                          0)
 266
 267 U_BOOT_I2C_ADAP_COMPLETE(lpc32xx_1, lpc32xx_i2c_init, lpc32xx_i2c_probe_chip,
 268                          lpc32xx_i2c_read, lpc32xx_i2c_write,
 269                          lpc32xx_i2c_set_bus_speed,
 270                          CONFIG_SYS_I2C_LPC32XX_SPEED,
 271                          CONFIG_SYS_I2C_LPC32XX_SLAVE,
 272                          1)
 273
 274 U_BOOT_I2C_ADAP_COMPLETE(lpc32xx_2, lpc32xx_i2c_init, NULL,
 275                          lpc32xx_i2c_read, lpc32xx_i2c_write,
 276                          lpc32xx_i2c_set_bus_speed,
 277                          100000,
 278                          0,
 279                          2)
 280 #else /* CONFIG_DM_I2C */
 281 static int lpc32xx_i2c_probe(struct udevice *bus)
 282 {
 283         struct lpc32xx_i2c_dev *dev = dev_get_platdata(bus);
 284         bus->seq = dev->index;
 285
 286         __i2c_init(dev->base, dev->speed, 0, dev->index);
 287         return 0;
 288 }
 289
 290 static int lpc32xx_i2c_probe_chip(struct udevice *bus, u32 chip_addr,
 291                                   u32 chip_flags)
 292 {
 293         struct lpc32xx_i2c_dev *dev = dev_get_platdata(bus);
 294         return __i2c_probe_chip(dev->base, chip_addr);
 295 }
 296
 297 static int lpc32xx_i2c_xfer(struct udevice *bus, struct i2c_msg *msg,
 298                 int nmsgs)
 299 {
 300         struct lpc32xx_i2c_dev *dev = dev_get_platdata(bus);
 301         struct i2c_msg *dmsg, *omsg, dummy;
 302         uint i = 0, address = 0;
 303
 304         memset(&dummy, 0, sizeof(struct i2c_msg));
 305
 306         /* We expect either two messages (one with an offset and one with the
 307          * actual data) or one message (just data)
 308          */
 309         if (nmsgs > 2 || nmsgs == 0) {
 310                 debug("%s: Only one or two messages are supported.", __func__);
 311                 return -1;
 312         }
 313
 314         omsg = nmsgs == 1 ? &dummy : msg;
 315         dmsg = nmsgs == 1 ? msg : msg + 1;
 316
 317         /* the address is expected to be a uint, not a array. */
 318         address = omsg->buf[0];
 319         for (i = 1; i < omsg->len; i++)
 320                 address = (address << 8) + omsg->buf[i];
 321
 322         if (dmsg->flags & I2C_M_RD)
 323                 return __i2c_read(dev->base, dmsg->addr, address,
 324                                   omsg->len, dmsg->buf, dmsg->len);
 325         else
 326                 return __i2c_write(dev->base, dmsg->addr, address,
 327                                    omsg->len, dmsg->buf, dmsg->len);
 328 }
 329
 330 static int lpc32xx_i2c_set_bus_speed(struct udevice *bus, unsigned int speed)
 331 {
 332         struct lpc32xx_i2c_dev *dev = dev_get_platdata(bus);
 333         return __i2c_set_bus_speed(dev->base, speed, dev->index);
 334 }
 335
 336 static int lpc32xx_i2c_reset(struct udevice *bus)
 337 {
 338         struct lpc32xx_i2c_dev *dev = dev_get_platdata(bus);
 339
 340         __i2c_init(dev->base, dev->speed, 0, dev->index);
 341         return 0;
 342 }
 343
 344 static const struct dm_i2c_ops lpc32xx_i2c_ops = {
 345         .xfer          = lpc32xx_i2c_xfer,
 346         .probe_chip    = lpc32xx_i2c_probe_chip,
 347         .deblock       = lpc32xx_i2c_reset,
 348         .set_bus_speed = lpc32xx_i2c_set_bus_speed,
 349 };
 350
 351 U_BOOT_DRIVER(i2c_lpc32xx) = {
 352         .id                   = UCLASS_I2C,
 353         .name                 = "i2c_lpc32xx",
 354         .probe                = lpc32xx_i2c_probe,
 355         .ops                  = &lpc32xx_i2c_ops,
 356 };
 357 #endif /* CONFIG_DM_I2C */