drivers/i2c/sandbox_i2c.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Simulate an I2C port
   4  *
   5  * Copyright (c) 2014 Google, Inc
   6  */
   7
   8 #include <common.h>
   9 #include <dm.h>
  10 #include <errno.h>
  11 #include <i2c.h>
  12 #include <log.h>
  13 #include <asm/test.h>
  14 #include <dm/lists.h>
  15 #include <dm/device-internal.h>
  16
  17 struct sandbox_i2c_priv {
  18         bool test_mode;
  19 };
  20
  21 static int get_emul(struct udevice *dev, struct udevice **devp,
  22                     struct dm_i2c_ops **opsp)
  23 {
  24         struct dm_i2c_chip *plat;
  25         int ret;
  26
  27         *devp = NULL;
  28         *opsp = NULL;
  29         plat = dev_get_parent_platdata(dev);
  30         if (!plat->emul) {
  31                 ret = i2c_emul_find(dev, &plat->emul);
  32                 if (ret)
  33                         return ret;
  34         }
  35         *devp = plat->emul;
  36         *opsp = i2c_get_ops(plat->emul);
  37
  38         return 0;
  39 }
  40
  41 void sandbox_i2c_set_test_mode(struct udevice *bus, bool test_mode)
  42 {
  43         struct sandbox_i2c_priv *priv = dev_get_priv(bus);
  44
  45         priv->test_mode = test_mode;
  46 }
  47
  48 static int sandbox_i2c_xfer(struct udevice *bus, struct i2c_msg *msg,
  49                             int nmsgs)
  50 {
  51         struct dm_i2c_bus *i2c = dev_get_uclass_priv(bus);
  52         struct sandbox_i2c_priv *priv = dev_get_priv(bus);
  53         struct dm_i2c_ops *ops;
  54         struct udevice *emul, *dev;
  55         bool is_read;
  56         int ret;
  57
  58         /* Special test code to return success but with no emulation */
  59         if (priv->test_mode && msg->addr == SANDBOX_I2C_TEST_ADDR)
  60                 return 0;
  61
  62         ret = i2c_get_chip(bus, msg->addr, 1, &dev);
  63         if (ret)
  64                 return ret;
  65
  66         ret = get_emul(dev, &emul, &ops);
  67         if (ret)
  68                 return ret;
  69
  70         if (priv->test_mode) {
  71                 /*
  72                 * For testing, don't allow writing above 100KHz for writes and
  73                 * 400KHz for reads.
  74                 */
  75                 is_read = nmsgs > 1;
  76                 if (i2c->speed_hz > (is_read ? I2C_SPEED_FAST_RATE :
  77                                 I2C_SPEED_STANDARD_RATE)) {
  78                         debug("%s: Max speed exceeded\n", __func__);
  79                         return -EINVAL;
  80                 }
  81         }
  82
  83         return ops->xfer(emul, msg, nmsgs);
  84 }
  85
  86 static const struct dm_i2c_ops sandbox_i2c_ops = {
  87         .xfer           = sandbox_i2c_xfer,
  88 };
  89
  90 static const struct udevice_id sandbox_i2c_ids[] = {
  91         { .compatible = "sandbox,i2c" },
  92         { }
  93 };
  94
  95 U_BOOT_DRIVER(i2c_sandbox) = {
  96         .name   = "i2c_sandbox",
  97         .id     = UCLASS_I2C,
  98         .of_match = sandbox_i2c_ids,
  99         .ops    = &sandbox_i2c_ops,
 100         .priv_auto_alloc_size = sizeof(struct sandbox_i2c_priv),
 101 };