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/*
* I2C multiplexer using pinctrl API
*
* Copyright (c) 2012, NVIDIA CORPORATION. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#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;
struct pinctrl_state *state_idle;
};
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)
{
struct i2c_mux_pinctrl *mux = i2c_mux_priv(muxc);
return pinctrl_select_state(mux->pinctrl, mux->state_idle);
}
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_find_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,
sizeof(*mux) + num_names * sizeof(*mux->states),
0, i2c_mux_pinctrl_select, NULL);
if (!muxc) {
ret = -ENOMEM;
goto err_put_parent;
}
mux = i2c_mux_priv(muxc);
mux->states = (struct pinctrl_state **)(mux + 1);
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;
}
mux->state_idle = mux->states[i];
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 - !!mux->state_idle; i++) {
ret = i2c_mux_add_adapter(muxc, 0, i, 0);
if (ret)
goto err_del_adapter;
}
return 0;
err_del_adapter:
i2c_mux_del_adapters(muxc);
err_put_parent:
i2c_put_adapter(muxc->parent);
return ret;
}
static int 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);
return 0;
}
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 = of_match_ptr(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 <swarren@nvidia.com>");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:i2c-mux-pinctrl");
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