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

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Copyright (c) 2015 Google, Inc
   4  * Written by Simon Glass <sjg@chromium.org>
   5  */
   6
   7 #include <common.h>
   8 #include <dm.h>
   9 #include <errno.h>
  10 #include <i2c.h>
  11 #include <malloc.h>
  12 #include <dm/lists.h>
  13 #include <dm/root.h>
  14
  15 /**
  16  * struct i2c_mux: Information the uclass stores about an I2C mux
  17  *
  18  * @selected:   Currently selected mux, or -1 for none
  19  * @i2c_bus: I2C bus to use for communcation
  20  */
  21 struct i2c_mux {
  22         int selected;
  23         struct udevice *i2c_bus;
  24 };
  25
  26 /**
  27  * struct i2c_mux_bus: Information about each bus the mux controls
  28  *
  29  * @channel: Channel number used to select this bus
  30  */
  31 struct i2c_mux_bus {
  32         uint channel;
  33 };
  34
  35 /* Find out the mux channel number */
  36 static int i2c_mux_child_post_bind(struct udevice *dev)
  37 {
  38         struct i2c_mux_bus *plat = dev_get_parent_platdata(dev);
  39         int channel;
  40
  41         channel = dev_read_u32_default(dev, "reg", -1);
  42         if (channel < 0)
  43                 return -EINVAL;
  44         plat->channel = channel;
  45
  46         return 0;
  47 }
  48
  49 /* Find the I2C buses selected by this mux */
  50 static int i2c_mux_post_bind(struct udevice *mux)
  51 {
  52         ofnode node;
  53         int ret;
  54
  55         debug("%s: %s\n", __func__, mux->name);
  56         /*
  57          * There is no compatible string in the sub-nodes, so we must manually
  58          * bind these
  59          */
  60         dev_for_each_subnode(node, mux) {
  61                 struct udevice *dev;
  62                 const char *name;
  63                 const char *arrow = "->";
  64                 char *full_name;
  65                 int parent_name_len, arrow_len, mux_name_len, name_len;
  66
  67                 name = ofnode_get_name(node);
  68
  69                 /* Calculate lenghts of strings */
  70                 parent_name_len = strlen(mux->parent->name);
  71                 arrow_len = strlen(arrow);
  72                 mux_name_len = strlen(mux->name);
  73                 name_len = strlen(name);
  74
  75                 full_name = calloc(1, parent_name_len + arrow_len +
  76                                    mux_name_len + arrow_len + name_len + 1);
  77                 if (!full_name)
  78                         return -ENOMEM;
  79
  80                 /* Compose bus name */
  81                 strcat(full_name, mux->parent->name);
  82                 strcat(full_name, arrow);
  83                 strcat(full_name, mux->name);
  84                 strcat(full_name, arrow);
  85                 strcat(full_name, name);
  86
  87                 ret = device_bind_driver_to_node(mux, "i2c_mux_bus_drv",
  88                                                  full_name, node, &dev);
  89                 debug("   - bind ret=%d, %s, req_seq %d\n", ret,
  90                       dev ? dev->name : NULL, dev->req_seq);
  91                 if (ret)
  92                         return ret;
  93         }
  94
  95         return 0;
  96 }
  97
  98 /* Set up the mux ready for use */
  99 static int i2c_mux_post_probe(struct udevice *mux)
 100 {
 101         struct i2c_mux *priv = dev_get_uclass_priv(mux);
 102         int ret;
 103
 104         debug("%s: %s\n", __func__, mux->name);
 105         priv->selected = -1;
 106
 107         /* if parent is of i2c uclass already, we'll take that, otherwise
 108          * look if we find an i2c-parent phandle
 109          */
 110         if (UCLASS_I2C == device_get_uclass_id(mux->parent)) {
 111                 priv->i2c_bus = dev_get_parent(mux);
 112                 debug("%s: bus=%p/%s\n", __func__, priv->i2c_bus,
 113                       priv->i2c_bus->name);
 114                 return 0;
 115         }
 116
 117         ret = uclass_get_device_by_phandle(UCLASS_I2C, mux, "i2c-parent",
 118                                            &priv->i2c_bus);
 119         if (ret)
 120                 return ret;
 121         debug("%s: bus=%p/%s\n", __func__, priv->i2c_bus, priv->i2c_bus->name);
 122
 123         return 0;
 124 }
 125
 126 int i2c_mux_select(struct udevice *dev)
 127 {
 128         struct i2c_mux_bus *plat = dev_get_parent_platdata(dev);
 129         struct udevice *mux = dev->parent;
 130         struct i2c_mux_ops *ops = i2c_mux_get_ops(mux);
 131
 132         if (!ops->select)
 133                 return -ENOSYS;
 134
 135         return ops->select(mux, dev, plat->channel);
 136 }
 137
 138 int i2c_mux_deselect(struct udevice *dev)
 139 {
 140         struct i2c_mux_bus *plat = dev_get_parent_platdata(dev);
 141         struct udevice *mux = dev->parent;
 142         struct i2c_mux_ops *ops = i2c_mux_get_ops(mux);
 143
 144         if (!ops->deselect)
 145                 return -ENOSYS;
 146
 147         return ops->deselect(mux, dev, plat->channel);
 148 }
 149
 150 static int i2c_mux_bus_set_bus_speed(struct udevice *dev, unsigned int speed)
 151 {
 152         struct udevice *mux = dev->parent;
 153         struct i2c_mux *priv = dev_get_uclass_priv(mux);
 154         int ret, ret2;
 155
 156         ret = i2c_mux_select(dev);
 157         if (ret)
 158                 return ret;
 159         ret = dm_i2c_set_bus_speed(priv->i2c_bus, speed);
 160         ret2 = i2c_mux_deselect(dev);
 161
 162         return ret ? ret : ret2;
 163 }
 164
 165 static int i2c_mux_bus_probe(struct udevice *dev, uint chip_addr,
 166                              uint chip_flags)
 167 {
 168         struct udevice *mux = dev->parent;
 169         struct i2c_mux *priv = dev_get_uclass_priv(mux);
 170         struct dm_i2c_ops *ops = i2c_get_ops(priv->i2c_bus);
 171         int ret, ret2;
 172
 173         debug("%s: %s, bus %s\n", __func__, dev->name, priv->i2c_bus->name);
 174         if (!ops->probe_chip)
 175                 return -ENOSYS;
 176         ret = i2c_mux_select(dev);
 177         if (ret)
 178                 return ret;
 179         ret = ops->probe_chip(priv->i2c_bus, chip_addr, chip_flags);
 180         ret2 = i2c_mux_deselect(dev);
 181
 182         return ret ? ret : ret2;
 183 }
 184
 185 static int i2c_mux_bus_xfer(struct udevice *dev, struct i2c_msg *msg,
 186                             int nmsgs)
 187 {
 188         struct udevice *mux = dev->parent;
 189         struct i2c_mux *priv = dev_get_uclass_priv(mux);
 190         struct dm_i2c_ops *ops = i2c_get_ops(priv->i2c_bus);
 191         int ret, ret2;
 192
 193         debug("%s: %s, bus %s\n", __func__, dev->name, priv->i2c_bus->name);
 194         if (!ops->xfer)
 195                 return -ENOSYS;
 196         ret = i2c_mux_select(dev);
 197         if (ret)
 198                 return ret;
 199         ret = ops->xfer(priv->i2c_bus, msg, nmsgs);
 200         ret2 = i2c_mux_deselect(dev);
 201
 202         return ret ? ret : ret2;
 203 }
 204
 205 static const struct dm_i2c_ops i2c_mux_bus_ops = {
 206         .xfer           = i2c_mux_bus_xfer,
 207         .probe_chip     = i2c_mux_bus_probe,
 208         .set_bus_speed  = i2c_mux_bus_set_bus_speed,
 209 };
 210
 211 U_BOOT_DRIVER(i2c_mux_bus) = {
 212         .name           = "i2c_mux_bus_drv",
 213         .id             = UCLASS_I2C,
 214         .ops    = &i2c_mux_bus_ops,
 215 };
 216
 217 UCLASS_DRIVER(i2c_mux) = {
 218         .id             = UCLASS_I2C_MUX,
 219         .name           = "i2c_mux",
 220         .post_bind      = i2c_mux_post_bind,
 221         .post_probe     = i2c_mux_post_probe,
 222         .per_device_auto_alloc_size = sizeof(struct i2c_mux),
 223         .per_child_platdata_auto_alloc_size = sizeof(struct i2c_mux_bus),
 224         .child_post_bind = i2c_mux_child_post_bind,
 225 };