Quelle  i2c-mux-pinctrl.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0-only
/*
 * I2C multiplexer using pinctrl API
 *
 * Copyright (c) 2012, NVIDIA CORPORATION.  All rights reserved.
 */

#include <linux/i2c.h>
#include <linux/i2c-mux.h>
#include <linux/module.h>
#include <linux/pinctrl/consumer.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/of.h>
#include "../../pinctrl/core.h"

struct i2c_mux_pinctrl {
 struct pinctrl *pinctrl;
 struct pinctrl_state *states[];
};

static int i2c_mux_pinctrl_select(struct i2c_mux_core *muxc, u32 chan)
{
 struct i2c_mux_pinctrl *mux = i2c_mux_priv(muxc);

 return pinctrl_select_state(mux->pinctrl, mux->states[chan]);
}

static int i2c_mux_pinctrl_deselect(struct i2c_mux_core *muxc, u32 chan)
{
 return i2c_mux_pinctrl_select(muxc, muxc->num_adapters);
}

static struct i2c_adapter *i2c_mux_pinctrl_root_adapter(
 struct pinctrl_state *state)
{
 struct i2c_adapter *root = NULL;
 struct pinctrl_setting *setting;
 struct i2c_adapter *pin_root;

 list_for_each_entry(setting, &state->settings, node) {
  pin_root = i2c_root_adapter(setting->pctldev->dev);
  if (!pin_root)
   return NULL;
  if (!root)
   root = pin_root;
  else if (root != pin_root)
   return NULL;
 }

 return root;
}

static struct i2c_adapter *i2c_mux_pinctrl_parent_adapter(struct device *dev)
{
 struct device_node *np = dev->of_node;
 struct device_node *parent_np;
 struct i2c_adapter *parent;

 parent_np = of_parse_phandle(np, "i2c-parent", 0);
 if (!parent_np) {
  dev_err(dev, "Cannot parse i2c-parent\n");
  return ERR_PTR(-ENODEV);
 }
 parent = of_get_i2c_adapter_by_node(parent_np);
 of_node_put(parent_np);
 if (!parent)
  return ERR_PTR(-EPROBE_DEFER);

 return parent;
}

static int i2c_mux_pinctrl_probe(struct platform_device *pdev)
{
 struct device *dev = &pdev->dev;
 struct device_node *np = dev->of_node;
 struct i2c_mux_core *muxc;
 struct i2c_mux_pinctrl *mux;
 struct i2c_adapter *parent;
 struct i2c_adapter *root;
 int num_names, i, ret;
 const char *name;

 num_names = of_property_count_strings(np, "pinctrl-names");
 if (num_names < 0) {
  dev_err(dev, "Cannot parse pinctrl-names: %d\n",
   num_names);
  return num_names;
 }

 parent = i2c_mux_pinctrl_parent_adapter(dev);
 if (IS_ERR(parent))
  return PTR_ERR(parent);

 muxc = i2c_mux_alloc(parent, dev, num_names,
        struct_size(mux, states, num_names),
        0, i2c_mux_pinctrl_select, NULL);
 if (!muxc) {
  ret = -ENOMEM;
  goto err_put_parent;
 }
 mux = i2c_mux_priv(muxc);

 platform_set_drvdata(pdev, muxc);

 mux->pinctrl = devm_pinctrl_get(dev);
 if (IS_ERR(mux->pinctrl)) {
  ret = PTR_ERR(mux->pinctrl);
  dev_err(dev, "Cannot get pinctrl: %d\n", ret);
  goto err_put_parent;
 }

 for (i = 0; i < num_names; i++) {
  ret = of_property_read_string_index(np, "pinctrl-names", i,
          &name);
  if (ret < 0) {
   dev_err(dev, "Cannot parse pinctrl-names: %d\n", ret);
   goto err_put_parent;
  }

  mux->states[i] = pinctrl_lookup_state(mux->pinctrl, name);
  if (IS_ERR(mux->states[i])) {
   ret = PTR_ERR(mux->states[i]);
   dev_err(dev, "Cannot look up pinctrl state %s: %d\n",
    name, ret);
   goto err_put_parent;
  }

  if (strcmp(name, "idle"))
   continue;

  if (i != num_names - 1) {
   dev_err(dev, "idle state must be last\n");
   ret = -EINVAL;
   goto err_put_parent;
  }
  muxc->deselect = i2c_mux_pinctrl_deselect;
 }

 root = i2c_root_adapter(&muxc->parent->dev);

 muxc->mux_locked = true;
 for (i = 0; i < num_names; i++) {
  if (root != i2c_mux_pinctrl_root_adapter(mux->states[i])) {
   muxc->mux_locked = false;
   break;
  }
 }
 if (muxc->mux_locked)
  dev_info(dev, "mux-locked i2c mux\n");

 /* Do not add any adapter for the idle state (if it's there at all). */
 for (i = 0; i < num_names - !!muxc->deselect; i++) {
  ret = i2c_mux_add_adapter(muxc, 0, i);
  if (ret)
   goto err_del_adapter;
 }

 return 0;

err_del_adapter:
 i2c_mux_del_adapters(muxc);
err_put_parent:
 i2c_put_adapter(parent);

 return ret;
}

static void i2c_mux_pinctrl_remove(struct platform_device *pdev)
{
 struct i2c_mux_core *muxc = platform_get_drvdata(pdev);

 i2c_mux_del_adapters(muxc);
 i2c_put_adapter(muxc->parent);
}

static const struct of_device_id i2c_mux_pinctrl_of_match[] = {
 { .compatible = "i2c-mux-pinctrl", },
 {},
};
MODULE_DEVICE_TABLE(of, i2c_mux_pinctrl_of_match);

static struct platform_driver i2c_mux_pinctrl_driver = {
 .driver = {
  .name = "i2c-mux-pinctrl",
  .of_match_table = i2c_mux_pinctrl_of_match,
 },
 .probe = i2c_mux_pinctrl_probe,
 .remove = i2c_mux_pinctrl_remove,
};
module_platform_driver(i2c_mux_pinctrl_driver);

MODULE_DESCRIPTION("pinctrl-based I2C multiplexer driver");
MODULE_AUTHOR("Stephen Warren ");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:i2c-mux-pinctrl");