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/*
* General Purpose I2C multiplexer
*
* Copyright (C) 2017 Axentia Technologies AB
*
* Author: Peter Rosin <peda@axentia.se>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/i2c.h>
#include <linux/i2c-mux.h>
#include <linux/module.h>
#include <linux/mux/consumer.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
struct mux {
struct mux_control *control;
bool do_not_deselect;
};
static int i2c_mux_select(struct i2c_mux_core *muxc, u32 chan)
{
struct mux *mux = i2c_mux_priv(muxc);
int ret;
ret = mux_control_select(mux->control, chan);
mux->do_not_deselect = ret < 0;
return ret;
}
static int i2c_mux_deselect(struct i2c_mux_core *muxc, u32 chan)
{
struct mux *mux = i2c_mux_priv(muxc);
if (mux->do_not_deselect)
return 0;
return mux_control_deselect(mux->control);
}
static struct i2c_adapter *mux_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 const struct of_device_id i2c_mux_of_match[] = {
{ .compatible = "i2c-mux", },
{},
};
MODULE_DEVICE_TABLE(of, i2c_mux_of_match);
static int i2c_mux_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct device_node *np = dev->of_node;
struct device_node *child;
struct i2c_mux_core *muxc;
struct mux *mux;
struct i2c_adapter *parent;
int children;
int ret;
if (!np)
return -ENODEV;
mux = devm_kzalloc(dev, sizeof(*mux), GFP_KERNEL);
if (!mux)
return -ENOMEM;
mux->control = devm_mux_control_get(dev, NULL);
if (IS_ERR(mux->control)) {
if (PTR_ERR(mux->control) != -EPROBE_DEFER)
dev_err(dev, "failed to get control-mux\n");
return PTR_ERR(mux->control);
}
parent = mux_parent_adapter(dev);
if (IS_ERR(parent)) {
if (PTR_ERR(parent) != -EPROBE_DEFER)
dev_err(dev, "failed to get i2c-parent adapter\n");
return PTR_ERR(parent);
}
children = of_get_child_count(np);
muxc = i2c_mux_alloc(parent, dev, children, 0, 0,
i2c_mux_select, i2c_mux_deselect);
if (!muxc) {
ret = -ENOMEM;
goto err_parent;
}
muxc->priv = mux;
platform_set_drvdata(pdev, muxc);
muxc->mux_locked = of_property_read_bool(np, "mux-locked");
for_each_child_of_node(np, child) {
u32 chan;
ret = of_property_read_u32(child, "reg", &chan);
if (ret < 0) {
dev_err(dev, "no reg property for node '%s'\n",
child->name);
goto err_children;
}
if (chan >= mux_control_states(mux->control)) {
dev_err(dev, "invalid reg %u\n", chan);
ret = -EINVAL;
goto err_children;
}
ret = i2c_mux_add_adapter(muxc, 0, chan, 0);
if (ret)
goto err_children;
}
dev_info(dev, "%d-port mux on %s adapter\n", children, parent->name);
return 0;
err_children:
of_node_put(child);
i2c_mux_del_adapters(muxc);
err_parent:
i2c_put_adapter(parent);
return ret;
}
static int i2c_mux_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 struct platform_driver i2c_mux_driver = {
.probe = i2c_mux_probe,
.remove = i2c_mux_remove,
.driver = {
.name = "i2c-mux-gpmux",
.of_match_table = i2c_mux_of_match,
},
};
module_platform_driver(i2c_mux_driver);
MODULE_DESCRIPTION("General Purpose I2C multiplexer driver");
MODULE_AUTHOR("Peter Rosin <peda@axentia.se>");
MODULE_LICENSE("GPL v2");
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