blob: 8833888ded37408a694fa8eb275e66409ddb7309 [file] [log] [blame]
// 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 <common.h>
#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),
};