// SPDX-License-Identifier: GPL-2.0

/*

 * Multiplexer subsystem

 *

 * Based on the linux multiplexer framework

 *

 * Copyright (C) 2017 Axentia Technologies AB

 * Author: Peter Rosin <peda@axentia.se>

 *

 * Copyright (C) 2017-2018 Texas Instruments Incorporated - https://www.ti.com/

 * Jean-Jacques Hiblot <jjhiblot@ti.com>

 */

#define LOG_CATEGORY UCLASS_MUX

#include <dm.h>

#include <mux-internal.h>

#include <dm/device-internal.h>

#include <dm/device_compat.h>

#include <dm/devres.h>

#include <dt-bindings/mux/mux.h>

#include <linux/bug.h>

/*

 * The idle-as-is "state" is not an actual state that may be selected, it

 * only implies that the state should not be changed. So, use that state

 * as indication that the cached state of the multiplexer is unknown.

 */

#define MUX_CACHE_UNKNOWN MUX_IDLE_AS_IS

/**

 * mux_control_ops() - Get the mux_control ops.

 * @dev: The client device.

 *

 * Return: A pointer to the 'mux_control_ops' of the device.

 */

static inline const struct mux_control_ops *mux_dev_ops(struct udevice *dev)

{

  return (const struct mux_control_ops *)dev->driver->ops;

}

/**

 * mux_control_set() - Set the state of the given mux controller.

 * @mux: A multiplexer control

 * @state: The new requested state.

 *

 * Return: 0 if OK, or a negative error code.

 */

static int mux_control_set(struct mux_control *mux, int state)

{

  int ret = mux_dev_ops(mux->dev)->set(mux, state);

  mux->cached_state = ret < 0 ? MUX_CACHE_UNKNOWN : state;

  return ret;

}

unsigned int mux_control_states(struct mux_control *mux)

{

  return mux->states;

}

/**

 * __mux_control_select() - Select the given multiplexer state.

 * @mux: The mux-control to request a change of state from.

 * @state: The new requested state.

 *

 * Try to set the mux to the requested state. If not, try to revert if

 * appropriate.

 */

static int __mux_control_select(struct mux_control *mux, int state)

{

  int ret;

  if (WARN_ON(state < 0 || state >= mux->states))

    return -EINVAL;

  if (mux->cached_state == state)

    return 0;

  ret = mux_control_set(mux, state);

  if (ret >= 0)

    return 0;

  /* The mux update failed, try to revert if appropriate... */

  if (mux->idle_state != MUX_IDLE_AS_IS)

    mux_control_set(mux, mux->idle_state);

  return ret;

}

int mux_control_select(struct mux_control *mux, unsigned int state)

{

  int ret;

  if (mux->in_use)

    return -EBUSY;

  ret = __mux_control_select(mux, state);

  if (ret < 0)

    return ret;

  mux->in_use = true;

  return 0;

}

int mux_control_deselect(struct mux_control *mux)

{

  int ret = 0;

  if (mux->idle_state != MUX_IDLE_AS_IS &&

      mux->idle_state != mux->cached_state)

    ret = mux_control_set(mux, mux->idle_state);

  mux->in_use = false;

  return ret;

}

static int mux_of_xlate_default(struct mux_chip *mux_chip,

        struct ofnode_phandle_args *args,

        struct mux_control **muxp)

{

  struct mux_control *mux;

  int id;

  log_debug("%s(muxp=%p)\n", __func__, muxp);

  if (args->args_count > 1) {

    debug("Invalid args_count: %d\n", args->args_count);

    return -EINVAL;

  }

  if (args->args_count)

    id = args->args[0];

  else

    id = 0;

  if (id >= mux_chip->controllers) {

    pr_err("bad mux controller %u specified in %s\n",

      id, ofnode_get_name(args->node));

    return -ERANGE;

  }

  mux = &mux_chip->mux[id];

  mux->id = id;

  *muxp = mux;

  return 0;

}

/**

 * mux_get_by_indexed_prop() - Get a mux control by integer index

 * @dev: The client device.

 * @prop_name: Name of the device tree property.

 * @index: The index of the mux to get

 * @mux: A pointer to the 'mux_control' struct to initialize.

 *

 * Return: 0 of OK, -errno otherwise.

 */

static int mux_get_by_indexed_prop(struct udevice *dev, const char *prop_name,

           int index, struct mux_control **mux)

{

  int ret;

  struct ofnode_phandle_args args;

  struct udevice *dev_mux;

  const struct mux_control_ops *ops;

  struct mux_chip *mux_chip;

  log_debug("%s(dev=%p, index=%d, mux=%p)\n", __func__, dev, index, mux);

  ret = dev_read_phandle_with_args(dev, prop_name, "#mux-control-cells",

           0, index, &args);

  if (ret) {

    debug("%s: fdtdec_parse_phandle_with_args failed: err=%d\n",

          __func__, ret);

    return ret;

  }

  ret = uclass_get_device_by_ofnode(UCLASS_MUX, args.node, &dev_mux);

  if (ret) {

    debug("%s: uclass_get_device_by_ofnode failed: err=%d\n",

          __func__, ret);

    return ret;

  }

  mux_chip = dev_get_uclass_priv(dev_mux);

  ops = mux_dev_ops(dev_mux);

  if (ops->of_xlate)

    ret = ops->of_xlate(mux_chip, &args, mux);

  else

    ret = mux_of_xlate_default(mux_chip, &args, mux);

  if (ret) {

    debug("of_xlate() failed: %d\n", ret);

    return ret;

  }

  (*mux)->dev = dev_mux;

  return 0;

}

int mux_get_by_index(struct udevice *dev, int index, struct mux_control **mux)

{

  return mux_get_by_indexed_prop(dev, "mux-controls", index, mux);

}

int mux_control_get(struct udevice *dev, const char *name,

        struct mux_control **mux)

{

  int index;

  debug("%s(dev=%p, name=%s, mux=%p)\n", __func__, dev, name, mux);

  index = dev_read_stringlist_search(dev, "mux-control-names", name);

  if (index < 0) {

    debug("fdt_stringlist_search() failed: %d\n", index);

    return index;

  }

  return mux_get_by_index(dev, index, mux);

}

void mux_control_put(struct mux_control *mux)

{

  mux_control_deselect(mux);

}

/**

 * devm_mux_control_release() - Release the given managed mux.

 * @dev: The client device.

 * @res: Pointer to the mux to be released.

 *

 * This function is called by devres to release the mux. It reverses the

 * effects of mux_control_get().

 */

static void devm_mux_control_release(struct udevice *dev, void *res)

{

  mux_control_put(*(struct mux_control **)res);

}

struct mux_control *devm_mux_control_get(struct udevice *dev, const char *id)

{

  int rc;

  struct mux_control **mux;

  mux = devres_alloc(devm_mux_control_release,

         sizeof(struct mux_control *), __GFP_ZERO);

  if (unlikely(!mux))

    return ERR_PTR(-ENOMEM);

  rc = mux_control_get(dev, id, mux);

  if (rc)

    return ERR_PTR(rc);

  devres_add(dev, mux);

  return *mux;

}

int mux_alloc_controllers(struct udevice *dev, unsigned int controllers)

{

  int i;

  struct mux_chip *mux_chip = dev_get_uclass_priv(dev);

  mux_chip->mux = devm_kmalloc(dev,

             sizeof(struct mux_control) * controllers,

             __GFP_ZERO);

  if (!mux_chip->mux)

    return -ENOMEM;

  mux_chip->controllers = controllers;

  for (i = 0; i < mux_chip->controllers; ++i) {

    struct mux_control *mux = &mux_chip->mux[i];

    mux->dev = dev;

    mux->cached_state = MUX_CACHE_UNKNOWN;

    mux->idle_state = MUX_IDLE_AS_IS;

    mux->in_use = false;

    mux->id = i;

  }

  return 0;

}

static int mux_uclass_post_probe(struct udevice *dev)

{

  int i, ret;

  struct mux_chip *mux_chip = dev_get_uclass_priv(dev);

  /* Set all mux controllers to their idle state. */

  for (i = 0; i < mux_chip->controllers; ++i) {

    struct mux_control *mux = &mux_chip->mux[i];

    if (mux->idle_state == mux->cached_state)

      continue;

    ret = mux_control_set(mux, mux->idle_state);

    if (ret < 0) {

      dev_err(dev, "unable to set idle state\n");

      return ret;

    }

  }

  return 0;

}

int dm_mux_init(void)

{

  struct uclass *uc;

  struct udevice *dev;

  int ret;

  ret = uclass_get(UCLASS_MUX, &uc);

  if (ret < 0) {

    log_debug("unable to get MUX uclass\n");

    return ret;

  }

  uclass_foreach_dev(dev, uc) {

    if (dev_read_bool(dev, "u-boot,mux-autoprobe") ||

        dev_read_bool(dev, "idle-states")) {

      ret = device_probe(dev);

      if (ret)

        log_debug("unable to probe device %s\n",

            dev->name);

    }

  }

  return 0;

}

UCLASS_DRIVER(mux) = {

  .id   = UCLASS_MUX,

  .name   = "mux",

  .post_probe = mux_uclass_post_probe,

  .per_device_auto  = sizeof(struct mux_chip),

};