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

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * General Purpose I2C multiplexer
   4  *
   5  * Copyright (C) 2017 Axentia Technologies AB
   6  *
   7  * Author: Peter Rosin <peda@axentia.se>
   8  */
   9
  10 #include <linux/i2c.h>
  11 #include <linux/i2c-mux.h>
  12 #include <linux/module.h>
  13 #include <linux/mux/consumer.h>
  14 #include <linux/of.h>
  15 #include <linux/platform_device.h>
  16
  17 struct mux {
  18         struct mux_control *control;
  19
  20         bool do_not_deselect;
  21 };
  22
  23 static int i2c_mux_select(struct i2c_mux_core *muxc, u32 chan)
  24 {
  25         struct mux *mux = i2c_mux_priv(muxc);
  26         int ret;
  27
  28         ret = mux_control_select(mux->control, chan);
  29         mux->do_not_deselect = ret < 0;
  30
  31         return ret;
  32 }
  33
  34 static int i2c_mux_deselect(struct i2c_mux_core *muxc, u32 chan)
  35 {
  36         struct mux *mux = i2c_mux_priv(muxc);
  37
  38         if (mux->do_not_deselect)
  39                 return 0;
  40
  41         return mux_control_deselect(mux->control);
  42 }
  43
  44 static struct i2c_adapter *mux_parent_adapter(struct device *dev)
  45 {
  46         struct device_node *np = dev->of_node;
  47         struct device_node *parent_np;
  48         struct i2c_adapter *parent;
  49
  50         parent_np = of_parse_phandle(np, "i2c-parent", 0);
  51         if (!parent_np) {
  52                 dev_err(dev, "Cannot parse i2c-parent\n");
  53                 return ERR_PTR(-ENODEV);
  54         }
  55         parent = of_get_i2c_adapter_by_node(parent_np);
  56         of_node_put(parent_np);
  57         if (!parent)
  58                 return ERR_PTR(-EPROBE_DEFER);
  59
  60         return parent;
  61 }
  62
  63 static const struct of_device_id i2c_mux_of_match[] = {
  64         { .compatible = "i2c-mux", },
  65         {},
  66 };
  67 MODULE_DEVICE_TABLE(of, i2c_mux_of_match);
  68
  69 static int i2c_mux_probe(struct platform_device *pdev)
  70 {
  71         struct device *dev = &pdev->dev;
  72         struct device_node *np = dev->of_node;
  73         struct device_node *child;
  74         struct i2c_mux_core *muxc;
  75         struct mux *mux;
  76         struct i2c_adapter *parent;
  77         int children;
  78         int ret;
  79
  80         if (!np)
  81                 return -ENODEV;
  82
  83         mux = devm_kzalloc(dev, sizeof(*mux), GFP_KERNEL);
  84         if (!mux)
  85                 return -ENOMEM;
  86
  87         mux->control = devm_mux_control_get(dev, NULL);
  88         if (IS_ERR(mux->control))
  89                 return dev_err_probe(dev, PTR_ERR(mux->control),
  90                                      "failed to get control-mux\n");
  91
  92         parent = mux_parent_adapter(dev);
  93         if (IS_ERR(parent))
  94                 return dev_err_probe(dev, PTR_ERR(parent),
  95                                      "failed to get i2c-parent adapter\n");
  96
  97         children = of_get_child_count(np);
  98
  99         muxc = i2c_mux_alloc(parent, dev, children, 0, 0,
 100                              i2c_mux_select, i2c_mux_deselect);
 101         if (!muxc) {
 102                 ret = -ENOMEM;
 103                 goto err_parent;
 104         }
 105         muxc->priv = mux;
 106
 107         platform_set_drvdata(pdev, muxc);
 108
 109         muxc->mux_locked = of_property_read_bool(np, "mux-locked");
 110
 111         for_each_child_of_node(np, child) {
 112                 u32 chan;
 113
 114                 ret = of_property_read_u32(child, "reg", &chan);
 115                 if (ret < 0) {
 116                         dev_err(dev, "no reg property for node '%pOFn'\n",
 117                                 child);
 118                         goto err_children;
 119                 }
 120
 121                 if (chan >= mux_control_states(mux->control)) {
 122                         dev_err(dev, "invalid reg %u\n", chan);
 123                         ret = -EINVAL;
 124                         goto err_children;
 125                 }
 126
 127                 ret = i2c_mux_add_adapter(muxc, 0, chan);
 128                 if (ret)
 129                         goto err_children;
 130         }
 131
 132         dev_info(dev, "%d-port mux on %s adapter\n", children, parent->name);
 133
 134         return 0;
 135
 136 err_children:
 137         of_node_put(child);
 138         i2c_mux_del_adapters(muxc);
 139 err_parent:
 140         i2c_put_adapter(parent);
 141
 142         return ret;
 143 }
 144
 145 static void i2c_mux_remove(struct platform_device *pdev)
 146 {
 147         struct i2c_mux_core *muxc = platform_get_drvdata(pdev);
 148
 149         i2c_mux_del_adapters(muxc);
 150         i2c_put_adapter(muxc->parent);
 151 }
 152
 153 static struct platform_driver i2c_mux_driver = {
 154         .probe  = i2c_mux_probe,
 155         .remove = i2c_mux_remove,
 156         .driver = {
 157                 .name   = "i2c-mux-gpmux",
 158                 .of_match_table = i2c_mux_of_match,
 159         },
 160 };
 161 module_platform_driver(i2c_mux_driver);
 162
 163 MODULE_DESCRIPTION("General Purpose I2C multiplexer driver");
 164 MODULE_AUTHOR("Peter Rosin <peda@axentia.se>");
 165 MODULE_LICENSE("GPL v2");