kernel/drivers/i2c/muxes/i2c-mux-pinctrl.c

   1 /*
   2  * I2C multiplexer using pinctrl API
   3  *
   4  * Copyright (c) 2012, NVIDIA CORPORATION.  All rights reserved.
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms and conditions of the GNU General Public License,
   8  * version 2, as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  13  * more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17  */
  18
  19 #include <linux/i2c.h>
  20 #include <linux/i2c-mux.h>
  21 #include <linux/module.h>
  22 #include <linux/pinctrl/consumer.h>
  23 #include <linux/i2c-mux-pinctrl.h>
  24 #include <linux/platform_device.h>
  25 #include <linux/slab.h>
  26 #include <linux/of.h>
  27
  28 struct i2c_mux_pinctrl {
  29         struct device *dev;
  30         struct i2c_mux_pinctrl_platform_data *pdata;
  31         struct pinctrl *pinctrl;
  32         struct pinctrl_state **states;
  33         struct pinctrl_state *state_idle;
  34         struct i2c_adapter *parent;
  35         struct i2c_adapter **busses;
  36 };
  37
  38 static int i2c_mux_pinctrl_select(struct i2c_adapter *adap, void *data,
  39                                   u32 chan)
  40 {
  41         struct i2c_mux_pinctrl *mux = data;
  42
  43         return pinctrl_select_state(mux->pinctrl, mux->states[chan]);
  44 }
  45
  46 static int i2c_mux_pinctrl_deselect(struct i2c_adapter *adap, void *data,
  47                                     u32 chan)
  48 {
  49         struct i2c_mux_pinctrl *mux = data;
  50
  51         return pinctrl_select_state(mux->pinctrl, mux->state_idle);
  52 }
  53
  54 #ifdef CONFIG_OF
  55 static int i2c_mux_pinctrl_parse_dt(struct i2c_mux_pinctrl *mux,
  56                                 struct platform_device *pdev)
  57 {
  58         struct device_node *np = pdev->dev.of_node;
  59         int num_names, i, ret;
  60         struct device_node *adapter_np;
  61         struct i2c_adapter *adapter;
  62
  63         if (!np)
  64                 return 0;
  65
  66         mux->pdata = devm_kzalloc(&pdev->dev, sizeof(*mux->pdata), GFP_KERNEL);
  67         if (!mux->pdata) {
  68                 dev_err(mux->dev,
  69                         "Cannot allocate i2c_mux_pinctrl_platform_data\n");
  70                 return -ENOMEM;
  71         }
  72
  73         num_names = of_property_count_strings(np, "pinctrl-names");
  74         if (num_names < 0) {
  75                 dev_err(mux->dev, "Cannot parse pinctrl-names: %d\n",
  76                         num_names);
  77                 return num_names;
  78         }
  79
  80         mux->pdata->pinctrl_states = devm_kzalloc(&pdev->dev,
  81                 sizeof(*mux->pdata->pinctrl_states) * num_names,
  82                 GFP_KERNEL);
  83         if (!mux->pdata->pinctrl_states) {
  84                 dev_err(mux->dev, "Cannot allocate pinctrl_states\n");
  85                 return -ENOMEM;
  86         }
  87
  88         for (i = 0; i < num_names; i++) {
  89                 ret = of_property_read_string_index(np, "pinctrl-names", i,
  90                         &mux->pdata->pinctrl_states[mux->pdata->bus_count]);
  91                 if (ret < 0) {
  92                         dev_err(mux->dev, "Cannot parse pinctrl-names: %d\n",
  93                                 ret);
  94                         return ret;
  95                 }
  96                 if (!strcmp(mux->pdata->pinctrl_states[mux->pdata->bus_count],
  97                             "idle")) {
  98                         if (i != num_names - 1) {
  99                                 dev_err(mux->dev, "idle state must be last\n");
 100                                 return -EINVAL;
 101                         }
 102                         mux->pdata->pinctrl_state_idle = "idle";
 103                 } else {
 104                         mux->pdata->bus_count++;
 105                 }
 106         }
 107
 108         adapter_np = of_parse_phandle(np, "i2c-parent", 0);
 109         if (!adapter_np) {
 110                 dev_err(mux->dev, "Cannot parse i2c-parent\n");
 111                 return -ENODEV;
 112         }
 113         adapter = of_find_i2c_adapter_by_node(adapter_np);
 114         if (!adapter) {
 115                 dev_err(mux->dev, "Cannot find parent bus\n");
 116                 return -EPROBE_DEFER;
 117         }
 118         mux->pdata->parent_bus_num = i2c_adapter_id(adapter);
 119         put_device(&adapter->dev);
 120
 121         return 0;
 122 }
 123 #else
 124 static inline int i2c_mux_pinctrl_parse_dt(struct i2c_mux_pinctrl *mux,
 125                                            struct platform_device *pdev)
 126 {
 127         return 0;
 128 }
 129 #endif
 130
 131 static int i2c_mux_pinctrl_probe(struct platform_device *pdev)
 132 {
 133         struct i2c_mux_pinctrl *mux;
 134         int (*deselect)(struct i2c_adapter *, void *, u32);
 135         int i, ret;
 136
 137         mux = devm_kzalloc(&pdev->dev, sizeof(*mux), GFP_KERNEL);
 138         if (!mux) {
 139                 dev_err(&pdev->dev, "Cannot allocate i2c_mux_pinctrl\n");
 140                 ret = -ENOMEM;
 141                 goto err;
 142         }
 143         platform_set_drvdata(pdev, mux);
 144
 145         mux->dev = &pdev->dev;
 146
 147         mux->pdata = dev_get_platdata(&pdev->dev);
 148         if (!mux->pdata) {
 149                 ret = i2c_mux_pinctrl_parse_dt(mux, pdev);
 150                 if (ret < 0)
 151                         goto err;
 152         }
 153         if (!mux->pdata) {
 154                 dev_err(&pdev->dev, "Missing platform data\n");
 155                 ret = -ENODEV;
 156                 goto err;
 157         }
 158
 159         mux->states = devm_kzalloc(&pdev->dev,
 160                                    sizeof(*mux->states) * mux->pdata->bus_count,
 161                                    GFP_KERNEL);
 162         if (!mux->states) {
 163                 dev_err(&pdev->dev, "Cannot allocate states\n");
 164                 ret = -ENOMEM;
 165                 goto err;
 166         }
 167
 168         mux->busses = devm_kzalloc(&pdev->dev,
 169                                    sizeof(*mux->busses) * mux->pdata->bus_count,
 170                                    GFP_KERNEL);
 171         if (!mux->busses) {
 172                 dev_err(&pdev->dev, "Cannot allocate busses\n");
 173                 ret = -ENOMEM;
 174                 goto err;
 175         }
 176
 177         mux->pinctrl = devm_pinctrl_get(&pdev->dev);
 178         if (IS_ERR(mux->pinctrl)) {
 179                 ret = PTR_ERR(mux->pinctrl);
 180                 dev_err(&pdev->dev, "Cannot get pinctrl: %d\n", ret);
 181                 goto err;
 182         }
 183         for (i = 0; i < mux->pdata->bus_count; i++) {
 184                 mux->states[i] = pinctrl_lookup_state(mux->pinctrl,
 185                                                 mux->pdata->pinctrl_states[i]);
 186                         if (IS_ERR(mux->states[i])) {
 187                                 ret = PTR_ERR(mux->states[i]);
 188                                 dev_err(&pdev->dev,
 189                                         "Cannot look up pinctrl state %s: %d\n",
 190                                         mux->pdata->pinctrl_states[i], ret);
 191                                 goto err;
 192                         }
 193         }
 194         if (mux->pdata->pinctrl_state_idle) {
 195                 mux->state_idle = pinctrl_lookup_state(mux->pinctrl,
 196                                                 mux->pdata->pinctrl_state_idle);
 197                 if (IS_ERR(mux->state_idle)) {
 198                         ret = PTR_ERR(mux->state_idle);
 199                         dev_err(&pdev->dev,
 200                                 "Cannot look up pinctrl state %s: %d\n",
 201                                 mux->pdata->pinctrl_state_idle, ret);
 202                         goto err;
 203                 }
 204
 205                 deselect = i2c_mux_pinctrl_deselect;
 206         } else {
 207                 deselect = NULL;
 208         }
 209
 210         mux->parent = i2c_get_adapter(mux->pdata->parent_bus_num);
 211         if (!mux->parent) {
 212                 dev_err(&pdev->dev, "Parent adapter (%d) not found\n",
 213                         mux->pdata->parent_bus_num);
 214                 ret = -EPROBE_DEFER;
 215                 goto err;
 216         }
 217
 218         for (i = 0; i < mux->pdata->bus_count; i++) {
 219                 u32 bus = mux->pdata->base_bus_num ?
 220                                 (mux->pdata->base_bus_num + i) : 0;
 221
 222                 mux->busses[i] = i2c_add_mux_adapter(mux->parent, &pdev->dev,
 223                                                      mux, bus, i, 0,
 224                                                      i2c_mux_pinctrl_select,
 225                                                      deselect);
 226                 if (!mux->busses[i]) {
 227                         ret = -ENODEV;
 228                         dev_err(&pdev->dev, "Failed to add adapter %d\n", i);
 229                         goto err_del_adapter;
 230                 }
 231         }
 232
 233         return 0;
 234
 235 err_del_adapter:
 236         for (; i > 0; i--)
 237                 i2c_del_mux_adapter(mux->busses[i - 1]);
 238         i2c_put_adapter(mux->parent);
 239 err:
 240         return ret;
 241 }
 242
 243 static int i2c_mux_pinctrl_remove(struct platform_device *pdev)
 244 {
 245         struct i2c_mux_pinctrl *mux = platform_get_drvdata(pdev);
 246         int i;
 247
 248         for (i = 0; i < mux->pdata->bus_count; i++)
 249                 i2c_del_mux_adapter(mux->busses[i]);
 250
 251         i2c_put_adapter(mux->parent);
 252
 253         return 0;
 254 }
 255
 256 #ifdef CONFIG_OF
 257 static const struct of_device_id i2c_mux_pinctrl_of_match[] = {
 258         { .compatible = "i2c-mux-pinctrl", },
 259         {},
 260 };
 261 MODULE_DEVICE_TABLE(of, i2c_mux_pinctrl_of_match);
 262 #endif
 263
 264 static struct platform_driver i2c_mux_pinctrl_driver = {
 265         .driver = {
 266                 .name   = "i2c-mux-pinctrl",
 267                 .of_match_table = of_match_ptr(i2c_mux_pinctrl_of_match),
 268         },
 269         .probe  = i2c_mux_pinctrl_probe,
 270         .remove = i2c_mux_pinctrl_remove,
 271 };
 272 module_platform_driver(i2c_mux_pinctrl_driver);
 273
 274 MODULE_DESCRIPTION("pinctrl-based I2C multiplexer driver");
 275 MODULE_AUTHOR("Stephen Warren <swarren@nvidia.com>");
 276 MODULE_LICENSE("GPL v2");
 277 MODULE_ALIAS("platform:i2c-mux-pinctrl");