git.sur5r.net Git - u-boot/blob - drivers/i2c/i2c-cdns.c

   1 /*
   2  * Copyright (C) 2015 Moritz Fischer <moritz.fischer@ettus.com>
   3  * IP from Cadence (ID T-CS-PE-0007-100, Version R1p10f2)
   4  *
   5  * This file is based on: drivers/i2c/zynq_i2c.c,
   6  * with added driver-model support and code cleanup.
   7  *
   8  * SPDX-License-Identifier:     GPL-2.0+
   9  */
  10
  11 #include <common.h>
  12 #include <linux/types.h>
  13 #include <linux/io.h>
  14 #include <asm/errno.h>
  15 #include <dm/device.h>
  16 #include <dm/root.h>
  17 #include <i2c.h>
  18 #include <fdtdec.h>
  19 #include <mapmem.h>
  20
  21 DECLARE_GLOBAL_DATA_PTR;
  22
  23 /* i2c register set */
  24 struct cdns_i2c_regs {
  25         u32 control;
  26         u32 status;
  27         u32 address;
  28         u32 data;
  29         u32 interrupt_status;
  30         u32 transfer_size;
  31         u32 slave_mon_pause;
  32         u32 time_out;
  33         u32 interrupt_mask;
  34         u32 interrupt_enable;
  35         u32 interrupt_disable;
  36 };
  37
  38 /* Control register fields */
  39 #define CDNS_I2C_CONTROL_RW             0x00000001
  40 #define CDNS_I2C_CONTROL_MS             0x00000002
  41 #define CDNS_I2C_CONTROL_NEA            0x00000004
  42 #define CDNS_I2C_CONTROL_ACKEN          0x00000008
  43 #define CDNS_I2C_CONTROL_HOLD           0x00000010
  44 #define CDNS_I2C_CONTROL_SLVMON         0x00000020
  45 #define CDNS_I2C_CONTROL_CLR_FIFO       0x00000040
  46 #define CDNS_I2C_CONTROL_DIV_B_SHIFT    8
  47 #define CDNS_I2C_CONTROL_DIV_B_MASK     0x00003F00
  48 #define CDNS_I2C_CONTROL_DIV_A_SHIFT    14
  49 #define CDNS_I2C_CONTROL_DIV_A_MASK     0x0000C000
  50
  51 /* Status register values */
  52 #define CDNS_I2C_STATUS_RXDV    0x00000020
  53 #define CDNS_I2C_STATUS_TXDV    0x00000040
  54 #define CDNS_I2C_STATUS_RXOVF   0x00000080
  55 #define CDNS_I2C_STATUS_BA      0x00000100
  56
  57 /* Interrupt register fields */
  58 #define CDNS_I2C_INTERRUPT_COMP         0x00000001
  59 #define CDNS_I2C_INTERRUPT_DATA         0x00000002
  60 #define CDNS_I2C_INTERRUPT_NACK         0x00000004
  61 #define CDNS_I2C_INTERRUPT_TO           0x00000008
  62 #define CDNS_I2C_INTERRUPT_SLVRDY       0x00000010
  63 #define CDNS_I2C_INTERRUPT_RXOVF        0x00000020
  64 #define CDNS_I2C_INTERRUPT_TXOVF        0x00000040
  65 #define CDNS_I2C_INTERRUPT_RXUNF        0x00000080
  66 #define CDNS_I2C_INTERRUPT_ARBLOST      0x00000200
  67
  68 #define CDNS_I2C_FIFO_DEPTH             16
  69 #define CDNS_I2C_TRANSFER_SIZE_MAX      255 /* Controller transfer limit */
  70
  71 #ifdef DEBUG
  72 static void cdns_i2c_debug_status(struct cdns_i2c_regs *cdns_i2c)
  73 {
  74         int int_status;
  75         int status;
  76         int_status = readl(&cdns_i2c->interrupt_status);
  77
  78         status = readl(&cdns_i2c->status);
  79         if (int_status || status) {
  80                 debug("Status: ");
  81                 if (int_status & CDNS_I2C_INTERRUPT_COMP)
  82                         debug("COMP ");
  83                 if (int_status & CDNS_I2C_INTERRUPT_DATA)
  84                         debug("DATA ");
  85                 if (int_status & CDNS_I2C_INTERRUPT_NACK)
  86                         debug("NACK ");
  87                 if (int_status & CDNS_I2C_INTERRUPT_TO)
  88                         debug("TO ");
  89                 if (int_status & CDNS_I2C_INTERRUPT_SLVRDY)
  90                         debug("SLVRDY ");
  91                 if (int_status & CDNS_I2C_INTERRUPT_RXOVF)
  92                         debug("RXOVF ");
  93                 if (int_status & CDNS_I2C_INTERRUPT_TXOVF)
  94                         debug("TXOVF ");
  95                 if (int_status & CDNS_I2C_INTERRUPT_RXUNF)
  96                         debug("RXUNF ");
  97                 if (int_status & CDNS_I2C_INTERRUPT_ARBLOST)
  98                         debug("ARBLOST ");
  99                 if (status & CDNS_I2C_STATUS_RXDV)
 100                         debug("RXDV ");
 101                 if (status & CDNS_I2C_STATUS_TXDV)
 102                         debug("TXDV ");
 103                 if (status & CDNS_I2C_STATUS_RXOVF)
 104                         debug("RXOVF ");
 105                 if (status & CDNS_I2C_STATUS_BA)
 106                         debug("BA ");
 107                 debug("TS%d ", readl(&cdns_i2c->transfer_size));
 108                 debug("\n");
 109         }
 110 }
 111 #endif
 112
 113 struct i2c_cdns_bus {
 114         int id;
 115         struct cdns_i2c_regs __iomem *regs;     /* register base */
 116 };
 117
 118
 119 /** cdns_i2c_probe() - Probe method
 120  * @dev: udevice pointer
 121  *
 122  * DM callback called when device is probed
 123  */
 124 static int cdns_i2c_probe(struct udevice *dev)
 125 {
 126         struct i2c_cdns_bus *bus = dev_get_priv(dev);
 127
 128         bus->regs = (struct cdns_i2c_regs *)dev_get_addr(dev);
 129         if (!bus->regs)
 130                 return -ENOMEM;
 131
 132         /* TODO: Calculate dividers based on CPU_CLK_1X */
 133         /* 111MHz / ( (3 * 17) * 22 ) = ~100KHz */
 134         writel((16 << CDNS_I2C_CONTROL_DIV_B_SHIFT) |
 135                 (2 << CDNS_I2C_CONTROL_DIV_A_SHIFT), &bus->regs->control);
 136
 137         /* Enable master mode, ack, and 7-bit addressing */
 138         setbits_le32(&bus->regs->control, CDNS_I2C_CONTROL_MS |
 139                 CDNS_I2C_CONTROL_ACKEN | CDNS_I2C_CONTROL_NEA);
 140
 141         debug("%s bus %d at %p\n", __func__, dev->seq, bus->regs);
 142
 143         return 0;
 144 }
 145
 146 static int cdns_i2c_remove(struct udevice *dev)
 147 {
 148         struct i2c_cdns_bus *bus = dev_get_priv(dev);
 149
 150         debug("%s bus %d at %p\n", __func__, dev->seq, bus->regs);
 151
 152         unmap_sysmem(bus->regs);
 153
 154         return 0;
 155 }
 156
 157 /* Wait for an interrupt */
 158 static u32 cdns_i2c_wait(struct cdns_i2c_regs *cdns_i2c, u32 mask)
 159 {
 160         int timeout, int_status;
 161
 162         for (timeout = 0; timeout < 100; timeout++) {
 163                 udelay(100);
 164                 int_status = readl(&cdns_i2c->interrupt_status);
 165                 if (int_status & mask)
 166                         break;
 167         }
 168
 169         /* Clear interrupt status flags */
 170         writel(int_status & mask, &cdns_i2c->interrupt_status);
 171
 172         return int_status & mask;
 173 }
 174
 175 static int cdns_i2c_set_bus_speed(struct udevice *dev, unsigned int speed)
 176 {
 177         if (speed != 100000) {
 178                 printf("%s, failed to set clock speed to %u\n", __func__,
 179                        speed);
 180                 return -EINVAL;
 181         }
 182
 183         return 0;
 184 }
 185
 186 /* Probe to see if a chip is present. */
 187 static int cdns_i2c_probe_chip(struct udevice *bus, uint chip_addr,
 188                                 uint chip_flags)
 189 {
 190         struct i2c_cdns_bus *i2c_bus = dev_get_priv(bus);
 191         struct cdns_i2c_regs *regs = i2c_bus->regs;
 192
 193         /* Attempt to read a byte */
 194         setbits_le32(&regs->control, CDNS_I2C_CONTROL_CLR_FIFO |
 195                 CDNS_I2C_CONTROL_RW);
 196         clrbits_le32(&regs->control, CDNS_I2C_CONTROL_HOLD);
 197         writel(0xFF, &regs->interrupt_status);
 198         writel(chip_addr, &regs->address);
 199         writel(1, &regs->transfer_size);
 200
 201         return (cdns_i2c_wait(regs, CDNS_I2C_INTERRUPT_COMP |
 202                 CDNS_I2C_INTERRUPT_NACK) &
 203                 CDNS_I2C_INTERRUPT_COMP) ? 0 : -ETIMEDOUT;
 204 }
 205
 206 static int cdns_i2c_write_data(struct i2c_cdns_bus *i2c_bus, u32 addr, u8 *data,
 207                                u32 len, bool next_is_read)
 208 {
 209         u8 *cur_data = data;
 210
 211         struct cdns_i2c_regs *regs = i2c_bus->regs;
 212
 213         setbits_le32(&regs->control, CDNS_I2C_CONTROL_CLR_FIFO |
 214                 CDNS_I2C_CONTROL_HOLD);
 215
 216         /* if next is a read, we need to clear HOLD, doesn't work */
 217         if (next_is_read)
 218                 clrbits_le32(&regs->control, CDNS_I2C_CONTROL_HOLD);
 219
 220         clrbits_le32(&regs->control, CDNS_I2C_CONTROL_RW);
 221
 222         writel(0xFF, &regs->interrupt_status);
 223         writel(addr, &regs->address);
 224
 225         while (len--) {
 226                 writel(*(cur_data++), &regs->data);
 227                 if (readl(&regs->transfer_size) == CDNS_I2C_FIFO_DEPTH) {
 228                         if (!cdns_i2c_wait(regs, CDNS_I2C_INTERRUPT_COMP)) {
 229                                 /* Release the bus */
 230                                 clrbits_le32(&regs->control,
 231                                              CDNS_I2C_CONTROL_HOLD);
 232                                 return -ETIMEDOUT;
 233                         }
 234                 }
 235         }
 236
 237         /* All done... release the bus */
 238         clrbits_le32(&regs->control, CDNS_I2C_CONTROL_HOLD);
 239         /* Wait for the address and data to be sent */
 240         if (!cdns_i2c_wait(regs, CDNS_I2C_INTERRUPT_COMP))
 241                 return -ETIMEDOUT;
 242         return 0;
 243 }
 244
 245 static int cdns_i2c_read_data(struct i2c_cdns_bus *i2c_bus, u32 addr, u8 *data,
 246                               u32 len)
 247 {
 248         u32 status;
 249         u32 i = 0;
 250         u8 *cur_data = data;
 251
 252         /* TODO: Fix this */
 253         struct cdns_i2c_regs *regs = i2c_bus->regs;
 254
 255         /* Check the hardware can handle the requested bytes */
 256         if ((len < 0) || (len > CDNS_I2C_TRANSFER_SIZE_MAX))
 257                 return -EINVAL;
 258
 259         setbits_le32(&regs->control, CDNS_I2C_CONTROL_CLR_FIFO |
 260                 CDNS_I2C_CONTROL_RW);
 261
 262         /* Start reading data */
 263         writel(addr, &regs->address);
 264         writel(len, &regs->transfer_size);
 265
 266         /* Wait for data */
 267         do {
 268                 status = cdns_i2c_wait(regs, CDNS_I2C_INTERRUPT_COMP |
 269                         CDNS_I2C_INTERRUPT_DATA);
 270                 if (!status) {
 271                         /* Release the bus */
 272                         clrbits_le32(&regs->control, CDNS_I2C_CONTROL_HOLD);
 273                         return -ETIMEDOUT;
 274                 }
 275                 debug("Read %d bytes\n",
 276                       len - readl(&regs->transfer_size));
 277                 for (; i < len - readl(&regs->transfer_size); i++)
 278                         *(cur_data++) = readl(&regs->data);
 279         } while (readl(&regs->transfer_size) != 0);
 280         /* All done... release the bus */
 281         clrbits_le32(&regs->control, CDNS_I2C_CONTROL_HOLD);
 282
 283 #ifdef DEBUG
 284         cdns_i2c_debug_status(regs);
 285 #endif
 286         return 0;
 287 }
 288
 289 static int cdns_i2c_xfer(struct udevice *dev, struct i2c_msg *msg,
 290                          int nmsgs)
 291 {
 292         struct i2c_cdns_bus *i2c_bus = dev_get_priv(dev);
 293         int ret;
 294
 295         debug("i2c_xfer: %d messages\n", nmsgs);
 296         for (; nmsgs > 0; nmsgs--, msg++) {
 297                 bool next_is_read = nmsgs > 1 && (msg[1].flags & I2C_M_RD);
 298
 299                 debug("i2c_xfer: chip=0x%x, len=0x%x\n", msg->addr, msg->len);
 300                 if (msg->flags & I2C_M_RD) {
 301                         ret = cdns_i2c_read_data(i2c_bus, msg->addr, msg->buf,
 302                                                  msg->len);
 303                 } else {
 304                         ret = cdns_i2c_write_data(i2c_bus, msg->addr, msg->buf,
 305                                                   msg->len, next_is_read);
 306                 }
 307                 if (ret) {
 308                         debug("i2c_write: error sending\n");
 309                         return -EREMOTEIO;
 310                 }
 311         }
 312
 313         return 0;
 314 }
 315
 316 static const struct dm_i2c_ops cdns_i2c_ops = {
 317         .xfer = cdns_i2c_xfer,
 318         .probe_chip = cdns_i2c_probe_chip,
 319         .set_bus_speed = cdns_i2c_set_bus_speed,
 320 };
 321
 322 static const struct udevice_id cdns_i2c_of_match[] = {
 323         { .compatible = "cdns,i2c-r1p10" },
 324         { /* end of table */ }
 325 };
 326
 327 U_BOOT_DRIVER(cdns_i2c) = {
 328         .name = "i2c-cdns",
 329         .id = UCLASS_I2C,
 330         .of_match = cdns_i2c_of_match,
 331         .probe = cdns_i2c_probe,
 332         .remove = cdns_i2c_remove,
 333         .priv_auto_alloc_size = sizeof(struct i2c_cdns_bus),
 334         .ops = &cdns_i2c_ops,
 335 };