drivers/i2c/muxes/i2c-mux-uclass.c

   1 /*
   2  * Copyright (c) 2015 Google, Inc
   3  * Written by Simon Glass <sjg@chromium.org>
   4  *
   5  * SPDX-License-Identifier:     GPL-2.0+
   6  */
   7
   8 #include <common.h>
   9 #include <dm.h>
  10 #include <errno.h>
  11 #include <i2c.h>
  12 #include <dm/lists.h>
  13 #include <dm/root.h>
  14
  15 DECLARE_GLOBAL_DATA_PTR;
  16
  17 /**
  18  * struct i2c_mux: Information the uclass stores about an I2C mux
  19  *
  20  * @selected:   Currently selected mux, or -1 for none
  21  * @i2c_bus: I2C bus to use for communcation
  22  */
  23 struct i2c_mux {
  24         int selected;
  25         struct udevice *i2c_bus;
  26 };
  27
  28 /**
  29  * struct i2c_mux_bus: Information about each bus the mux controls
  30  *
  31  * @channel: Channel number used to select this bus
  32  */
  33 struct i2c_mux_bus {
  34         uint channel;
  35 };
  36
  37 /* Find out the mux channel number */
  38 static int i2c_mux_child_post_bind(struct udevice *dev)
  39 {
  40         struct i2c_mux_bus *plat = dev_get_parent_platdata(dev);
  41         int channel;
  42
  43         channel = fdtdec_get_int(gd->fdt_blob, dev->of_offset, "reg", -1);
  44         if (channel < 0)
  45                 return -EINVAL;
  46         plat->channel = channel;
  47
  48         return 0;
  49 }
  50
  51 /* Find the I2C buses selected by this mux */
  52 static int i2c_mux_post_bind(struct udevice *mux)
  53 {
  54         const void *blob = gd->fdt_blob;
  55         int ret;
  56         int offset;
  57
  58         debug("%s: %s\n", __func__, mux->name);
  59         /*
  60          * There is no compatible string in the sub-nodes, so we must manually
  61          * bind these
  62          */
  63         for (offset = fdt_first_subnode(blob, mux->of_offset);
  64              offset > 0;
  65              offset = fdt_next_subnode(blob, offset)) {
  66                 struct udevice *dev;
  67                 const char *name;
  68
  69                 name = fdt_get_name(blob, offset, NULL);
  70                 ret = device_bind_driver_to_node(mux, "i2c_mux_bus_drv", name,
  71                                                  offset, &dev);
  72                 debug("   - bind ret=%d, %s\n", ret, dev ? dev->name : NULL);
  73                 if (ret)
  74                         return ret;
  75         }
  76
  77         return 0;
  78 }
  79
  80 /* Set up the mux ready for use */
  81 static int i2c_mux_post_probe(struct udevice *mux)
  82 {
  83         struct i2c_mux *priv = dev_get_uclass_priv(mux);
  84         int ret;
  85
  86         debug("%s: %s\n", __func__, mux->name);
  87         priv->selected = -1;
  88
  89         ret = uclass_get_device_by_phandle(UCLASS_I2C, mux, "i2c-parent",
  90                                            &priv->i2c_bus);
  91         if (ret)
  92                 return ret;
  93         debug("%s: bus=%p/%s\n", __func__, priv->i2c_bus, priv->i2c_bus->name);
  94
  95         return 0;
  96 }
  97
  98 int i2c_mux_select(struct udevice *dev)
  99 {
 100         struct i2c_mux_bus *plat = dev_get_parent_platdata(dev);
 101         struct udevice *mux = dev->parent;
 102         struct i2c_mux_ops *ops = i2c_mux_get_ops(mux);
 103
 104         if (!ops->select)
 105                 return -ENOSYS;
 106
 107         return ops->select(mux, dev, plat->channel);
 108 }
 109
 110 int i2c_mux_deselect(struct udevice *dev)
 111 {
 112         struct i2c_mux_bus *plat = dev_get_parent_platdata(dev);
 113         struct udevice *mux = dev->parent;
 114         struct i2c_mux_ops *ops = i2c_mux_get_ops(mux);
 115
 116         if (!ops->deselect)
 117                 return -ENOSYS;
 118
 119         return ops->deselect(mux, dev, plat->channel);
 120 }
 121
 122 static int i2c_mux_bus_set_bus_speed(struct udevice *dev, unsigned int speed)
 123 {
 124         struct udevice *mux = dev->parent;
 125         struct i2c_mux *priv = dev_get_uclass_priv(mux);
 126         int ret, ret2;
 127
 128         ret = i2c_mux_select(dev);
 129         if (ret)
 130                 return ret;
 131         ret = dm_i2c_set_bus_speed(priv->i2c_bus, speed);
 132         ret2 = i2c_mux_deselect(dev);
 133
 134         return ret ? ret : ret2;
 135 }
 136
 137 static int i2c_mux_bus_probe(struct udevice *dev, uint chip_addr,
 138                              uint chip_flags)
 139 {
 140         struct udevice *mux = dev->parent;
 141         struct i2c_mux *priv = dev_get_uclass_priv(mux);
 142         struct dm_i2c_ops *ops = i2c_get_ops(priv->i2c_bus);
 143         int ret, ret2;
 144
 145         debug("%s: %s, bus %s\n", __func__, dev->name, priv->i2c_bus->name);
 146         if (!ops->probe_chip)
 147                 return -ENOSYS;
 148         ret = i2c_mux_select(dev);
 149         if (ret)
 150                 return ret;
 151         ret = ops->probe_chip(priv->i2c_bus, chip_addr, chip_flags);
 152         ret2 = i2c_mux_deselect(dev);
 153
 154         return ret ? ret : ret2;
 155 }
 156
 157 static int i2c_mux_bus_xfer(struct udevice *dev, struct i2c_msg *msg,
 158                             int nmsgs)
 159 {
 160         struct udevice *mux = dev->parent;
 161         struct i2c_mux *priv = dev_get_uclass_priv(mux);
 162         struct dm_i2c_ops *ops = i2c_get_ops(priv->i2c_bus);
 163         int ret, ret2;
 164
 165         debug("%s: %s, bus %s\n", __func__, dev->name, priv->i2c_bus->name);
 166         if (!ops->xfer)
 167                 return -ENOSYS;
 168         ret = i2c_mux_select(dev);
 169         if (ret)
 170                 return ret;
 171         ret = ops->xfer(priv->i2c_bus, msg, nmsgs);
 172         ret2 = i2c_mux_deselect(dev);
 173
 174         return ret ? ret : ret2;
 175 }
 176
 177 static const struct dm_i2c_ops i2c_mux_bus_ops = {
 178         .xfer           = i2c_mux_bus_xfer,
 179         .probe_chip     = i2c_mux_bus_probe,
 180         .set_bus_speed  = i2c_mux_bus_set_bus_speed,
 181 };
 182
 183 U_BOOT_DRIVER(i2c_mux_bus) = {
 184         .name           = "i2c_mux_bus_drv",
 185         .id             = UCLASS_I2C,
 186         .per_child_auto_alloc_size = sizeof(struct dm_i2c_chip),
 187         .ops    = &i2c_mux_bus_ops,
 188 };
 189
 190 UCLASS_DRIVER(i2c_mux) = {
 191         .id             = UCLASS_I2C_MUX,
 192         .name           = "i2c_mux",
 193         .post_bind      = i2c_mux_post_bind,
 194         .post_probe     = i2c_mux_post_probe,
 195         .per_device_auto_alloc_size = sizeof(struct i2c_mux),
 196         .per_child_platdata_auto_alloc_size = sizeof(struct i2c_mux_bus),
 197         .child_post_bind = i2c_mux_child_post_bind,
 198 };