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 #include <dm/root.h>
  18
  19 DECLARE_GLOBAL_DATA_PTR;
  20
  21 struct sandbox_i2c_priv {
  22         bool test_mode;
  23 };
  24
  25 static int get_emul(struct udevice *dev, struct udevice **devp,
  26                     struct dm_i2c_ops **opsp)
  27 {
  28         struct dm_i2c_chip *plat;
  29         struct udevice *child;
  30         int ret;
  31
  32         *devp = NULL;
  33         *opsp = NULL;
  34         plat = dev_get_parent_platdata(dev);
  35         if (!plat->emul) {
  36                 ret = dm_scan_fdt_node(dev, gd->fdt_blob, dev->of_offset,
  37                                        false);
  38                 if (ret)
  39                         return ret;
  40
  41                 for (device_find_first_child(dev, &child); child;
  42                      device_find_next_child(&child)) {
  43                         if (device_get_uclass_id(child) != UCLASS_I2C_EMUL)
  44                                 continue;
  45
  46                         ret = device_probe(child);
  47                         if (ret)
  48                                 return ret;
  49
  50                         break;
  51                 }
  52
  53                 if (child)
  54                         plat->emul = child;
  55                 else
  56                         return -ENODEV;
  57         }
  58         *devp = plat->emul;
  59         *opsp = i2c_get_ops(plat->emul);
  60
  61         return 0;
  62 }
  63
  64 void sandbox_i2c_set_test_mode(struct udevice *bus, bool test_mode)
  65 {
  66         struct sandbox_i2c_priv *priv = dev_get_priv(bus);
  67
  68         priv->test_mode = test_mode;
  69 }
  70
  71 static int sandbox_i2c_xfer(struct udevice *bus, struct i2c_msg *msg,
  72                             int nmsgs)
  73 {
  74         struct dm_i2c_bus *i2c = dev_get_uclass_priv(bus);
  75         struct sandbox_i2c_priv *priv = dev_get_priv(bus);
  76         struct dm_i2c_ops *ops;
  77         struct udevice *emul, *dev;
  78         bool is_read;
  79         int ret;
  80
  81         /* Special test code to return success but with no emulation */
  82         if (priv->test_mode && msg->addr == SANDBOX_I2C_TEST_ADDR)
  83                 return 0;
  84
  85         ret = i2c_get_chip(bus, msg->addr, 1, &dev);
  86         if (ret)
  87                 return ret;
  88
  89         ret = get_emul(dev, &emul, &ops);
  90         if (ret)
  91                 return ret;
  92
  93         if (priv->test_mode) {
  94                 /*
  95                 * For testing, don't allow writing above 100KHz for writes and
  96                 * 400KHz for reads.
  97                 */
  98                 is_read = nmsgs > 1;
  99                 if (i2c->speed_hz > (is_read ? 400000 : 100000)) {
 100                         debug("%s: Max speed exceeded\n", __func__);
 101                         return -EINVAL;
 102                 }
 103         }
 104
 105         return ops->xfer(emul, msg, nmsgs);
 106 }
 107
 108 static const struct dm_i2c_ops sandbox_i2c_ops = {
 109         .xfer           = sandbox_i2c_xfer,
 110 };
 111
 112 static const struct udevice_id sandbox_i2c_ids[] = {
 113         { .compatible = "sandbox,i2c" },
 114         { }
 115 };
 116
 117 U_BOOT_DRIVER(i2c_sandbox) = {
 118         .name   = "i2c_sandbox",
 119         .id     = UCLASS_I2C,
 120         .of_match = sandbox_i2c_ids,
 121         .ops    = &sandbox_i2c_ops,
 122         .priv_auto_alloc_size = sizeof(struct sandbox_i2c_priv),
 123 };