drivers/i2c/sandbox_i2c.c

   1 /*
   2  * Simulate an I2C port
   3  *
   4  * Copyright (c) 2014 Google, Inc
   5  *
   6  * SPDX-License-Identifier:     GPL-2.0+
   7  */
   8
   9 #include <common.h>
  10 #include <dm.h>
  11 #include <errno.h>
  12 #include <i2c.h>
  13 #include <asm/test.h>
  14 #include <dm/lists.h>
  15 #include <dm/device-internal.h>
  16
  17 DECLARE_GLOBAL_DATA_PTR;
  18
  19 struct sandbox_i2c_priv {
  20         bool test_mode;
  21 };
  22
  23 static int get_emul(struct udevice *dev, struct udevice **devp,
  24                     struct dm_i2c_ops **opsp)
  25 {
  26         struct dm_i2c_chip *plat;
  27         struct udevice *child;
  28         int ret;
  29
  30         *devp = NULL;
  31         *opsp = NULL;
  32         plat = dev_get_parent_platdata(dev);
  33         if (!plat->emul) {
  34                 ret = dm_scan_fdt_dev(dev);
  35                 if (ret)
  36                         return ret;
  37
  38                 for (device_find_first_child(dev, &child); child;
  39                      device_find_next_child(&child)) {
  40                         if (device_get_uclass_id(child) != UCLASS_I2C_EMUL)
  41                                 continue;
  42
  43                         ret = device_probe(child);
  44                         if (ret)
  45                                 return ret;
  46
  47                         break;
  48                 }
  49
  50                 if (child)
  51                         plat->emul = child;
  52                 else
  53                         return -ENODEV;
  54         }
  55         *devp = plat->emul;
  56         *opsp = i2c_get_ops(plat->emul);
  57
  58         return 0;
  59 }
  60
  61 void sandbox_i2c_set_test_mode(struct udevice *bus, bool test_mode)
  62 {
  63         struct sandbox_i2c_priv *priv = dev_get_priv(bus);
  64
  65         priv->test_mode = test_mode;
  66 }
  67
  68 static int sandbox_i2c_xfer(struct udevice *bus, struct i2c_msg *msg,
  69                             int nmsgs)
  70 {
  71         struct dm_i2c_bus *i2c = dev_get_uclass_priv(bus);
  72         struct sandbox_i2c_priv *priv = dev_get_priv(bus);
  73         struct dm_i2c_ops *ops;
  74         struct udevice *emul, *dev;
  75         bool is_read;
  76         int ret;
  77
  78         /* Special test code to return success but with no emulation */
  79         if (priv->test_mode && msg->addr == SANDBOX_I2C_TEST_ADDR)
  80                 return 0;
  81
  82         ret = i2c_get_chip(bus, msg->addr, 1, &dev);
  83         if (ret)
  84                 return ret;
  85
  86         ret = get_emul(dev, &emul, &ops);
  87         if (ret)
  88                 return ret;
  89
  90         if (priv->test_mode) {
  91                 /*
  92                 * For testing, don't allow writing above 100KHz for writes and
  93                 * 400KHz for reads.
  94                 */
  95                 is_read = nmsgs > 1;
  96                 if (i2c->speed_hz > (is_read ? 400000 : 100000)) {
  97                         debug("%s: Max speed exceeded\n", __func__);
  98                         return -EINVAL;
  99                 }
 100         }
 101
 102         return ops->xfer(emul, msg, nmsgs);
 103 }
 104
 105 static const struct dm_i2c_ops sandbox_i2c_ops = {
 106         .xfer           = sandbox_i2c_xfer,
 107 };
 108
 109 static const struct udevice_id sandbox_i2c_ids[] = {
 110         { .compatible = "sandbox,i2c" },
 111         { }
 112 };
 113
 114 U_BOOT_DRIVER(i2c_sandbox) = {
 115         .name   = "i2c_sandbox",
 116         .id     = UCLASS_I2C,
 117         .of_match = sandbox_i2c_ids,
 118         .ops    = &sandbox_i2c_ops,
 119         .priv_auto_alloc_size = sizeof(struct sandbox_i2c_priv),
 120 };