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 <fdtdec.h>
  13 #include <i2c.h>
  14 #include <asm/test.h>
  15 #include <dm/lists.h>
  16 #include <dm/device-internal.h>
  17
  18 DECLARE_GLOBAL_DATA_PTR;
  19
  20 struct sandbox_i2c_priv {
  21         bool test_mode;
  22 };
  23
  24 static int get_emul(struct udevice *dev, struct udevice **devp,
  25                     struct dm_i2c_ops **opsp)
  26 {
  27         struct dm_i2c_chip *plat;
  28         struct udevice *child;
  29         int ret;
  30
  31         *devp = NULL;
  32         *opsp = NULL;
  33         plat = dev_get_parent_platdata(dev);
  34         if (!plat->emul) {
  35                 ret = dm_scan_fdt_dev(dev);
  36                 if (ret)
  37                         return ret;
  38
  39                 for (device_find_first_child(dev, &child); child;
  40                      device_find_next_child(&child)) {
  41                         if (device_get_uclass_id(child) != UCLASS_I2C_EMUL)
  42                                 continue;
  43
  44                         ret = device_probe(child);
  45                         if (ret)
  46                                 return ret;
  47
  48                         break;
  49                 }
  50
  51                 if (child)
  52                         plat->emul = child;
  53                 else
  54                         return -ENODEV;
  55         }
  56         *devp = plat->emul;
  57         *opsp = i2c_get_ops(plat->emul);
  58
  59         return 0;
  60 }
  61
  62 void sandbox_i2c_set_test_mode(struct udevice *bus, bool test_mode)
  63 {
  64         struct sandbox_i2c_priv *priv = dev_get_priv(bus);
  65
  66         priv->test_mode = test_mode;
  67 }
  68
  69 static int sandbox_i2c_xfer(struct udevice *bus, struct i2c_msg *msg,
  70                             int nmsgs)
  71 {
  72         struct dm_i2c_bus *i2c = dev_get_uclass_priv(bus);
  73         struct sandbox_i2c_priv *priv = dev_get_priv(bus);
  74         struct dm_i2c_ops *ops;
  75         struct udevice *emul, *dev;
  76         bool is_read;
  77         int ret;
  78
  79         /* Special test code to return success but with no emulation */
  80         if (priv->test_mode && msg->addr == SANDBOX_I2C_TEST_ADDR)
  81                 return 0;
  82
  83         ret = i2c_get_chip(bus, msg->addr, 1, &dev);
  84         if (ret)
  85                 return ret;
  86
  87         ret = get_emul(dev, &emul, &ops);
  88         if (ret)
  89                 return ret;
  90
  91         if (priv->test_mode) {
  92                 /*
  93                 * For testing, don't allow writing above 100KHz for writes and
  94                 * 400KHz for reads.
  95                 */
  96                 is_read = nmsgs > 1;
  97                 if (i2c->speed_hz > (is_read ? 400000 : 100000)) {
  98                         debug("%s: Max speed exceeded\n", __func__);
  99                         return -EINVAL;
 100                 }
 101         }
 102
 103         return ops->xfer(emul, msg, nmsgs);
 104 }
 105
 106 static const struct dm_i2c_ops sandbox_i2c_ops = {
 107         .xfer           = sandbox_i2c_xfer,
 108 };
 109
 110 static const struct udevice_id sandbox_i2c_ids[] = {
 111         { .compatible = "sandbox,i2c" },
 112         { }
 113 };
 114
 115 U_BOOT_DRIVER(i2c_sandbox) = {
 116         .name   = "i2c_sandbox",
 117         .id     = UCLASS_I2C,
 118         .of_match = sandbox_i2c_ids,
 119         .ops    = &sandbox_i2c_ops,
 120         .priv_auto_alloc_size = sizeof(struct sandbox_i2c_priv),
 121 };