280 lines
7.1 KiB
C
280 lines
7.1 KiB
C
/*
|
|
* 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/init.h>
|
|
#include <linux/module.h>
|
|
#include <linux/of_i2c.h>
|
|
#include <linux/pinctrl/consumer.h>
|
|
#include <linux/i2c-mux-pinctrl.h>
|
|
#include <linux/platform_device.h>
|
|
#include <linux/slab.h>
|
|
|
|
struct i2c_mux_pinctrl {
|
|
struct device *dev;
|
|
struct i2c_mux_pinctrl_platform_data *pdata;
|
|
struct pinctrl *pinctrl;
|
|
struct pinctrl_state **states;
|
|
struct pinctrl_state *state_idle;
|
|
struct i2c_adapter *parent;
|
|
struct i2c_adapter **busses;
|
|
};
|
|
|
|
static int i2c_mux_pinctrl_select(struct i2c_adapter *adap, void *data,
|
|
u32 chan)
|
|
{
|
|
struct i2c_mux_pinctrl *mux = data;
|
|
|
|
return pinctrl_select_state(mux->pinctrl, mux->states[chan]);
|
|
}
|
|
|
|
static int i2c_mux_pinctrl_deselect(struct i2c_adapter *adap, void *data,
|
|
u32 chan)
|
|
{
|
|
struct i2c_mux_pinctrl *mux = data;
|
|
|
|
return pinctrl_select_state(mux->pinctrl, mux->state_idle);
|
|
}
|
|
|
|
#ifdef CONFIG_OF
|
|
static int i2c_mux_pinctrl_parse_dt(struct i2c_mux_pinctrl *mux,
|
|
struct platform_device *pdev)
|
|
{
|
|
struct device_node *np = pdev->dev.of_node;
|
|
int num_names, i, ret;
|
|
struct device_node *adapter_np;
|
|
struct i2c_adapter *adapter;
|
|
|
|
if (!np)
|
|
return 0;
|
|
|
|
mux->pdata = devm_kzalloc(&pdev->dev, sizeof(*mux->pdata), GFP_KERNEL);
|
|
if (!mux->pdata) {
|
|
dev_err(mux->dev,
|
|
"Cannot allocate i2c_mux_pinctrl_platform_data\n");
|
|
return -ENOMEM;
|
|
}
|
|
|
|
num_names = of_property_count_strings(np, "pinctrl-names");
|
|
if (num_names < 0) {
|
|
dev_err(mux->dev, "Cannot parse pinctrl-names: %d\n",
|
|
num_names);
|
|
return num_names;
|
|
}
|
|
|
|
mux->pdata->pinctrl_states = devm_kzalloc(&pdev->dev,
|
|
sizeof(*mux->pdata->pinctrl_states) * num_names,
|
|
GFP_KERNEL);
|
|
if (!mux->pdata->pinctrl_states) {
|
|
dev_err(mux->dev, "Cannot allocate pinctrl_states\n");
|
|
return -ENOMEM;
|
|
}
|
|
|
|
for (i = 0; i < num_names; i++) {
|
|
ret = of_property_read_string_index(np, "pinctrl-names", i,
|
|
&mux->pdata->pinctrl_states[mux->pdata->bus_count]);
|
|
if (ret < 0) {
|
|
dev_err(mux->dev, "Cannot parse pinctrl-names: %d\n",
|
|
ret);
|
|
return ret;
|
|
}
|
|
if (!strcmp(mux->pdata->pinctrl_states[mux->pdata->bus_count],
|
|
"idle")) {
|
|
if (i != num_names - 1) {
|
|
dev_err(mux->dev, "idle state must be last\n");
|
|
return -EINVAL;
|
|
}
|
|
mux->pdata->pinctrl_state_idle = "idle";
|
|
} else {
|
|
mux->pdata->bus_count++;
|
|
}
|
|
}
|
|
|
|
adapter_np = of_parse_phandle(np, "i2c-parent", 0);
|
|
if (!adapter_np) {
|
|
dev_err(mux->dev, "Cannot parse i2c-parent\n");
|
|
return -ENODEV;
|
|
}
|
|
adapter = of_find_i2c_adapter_by_node(adapter_np);
|
|
if (!adapter) {
|
|
dev_err(mux->dev, "Cannot find parent bus\n");
|
|
return -ENODEV;
|
|
}
|
|
mux->pdata->parent_bus_num = i2c_adapter_id(adapter);
|
|
put_device(&adapter->dev);
|
|
|
|
return 0;
|
|
}
|
|
#else
|
|
static inline int i2c_mux_pinctrl_parse_dt(struct i2c_mux_pinctrl *mux,
|
|
struct platform_device *pdev)
|
|
{
|
|
return 0;
|
|
}
|
|
#endif
|
|
|
|
static int __devinit i2c_mux_pinctrl_probe(struct platform_device *pdev)
|
|
{
|
|
struct i2c_mux_pinctrl *mux;
|
|
int (*deselect)(struct i2c_adapter *, void *, u32);
|
|
int i, ret;
|
|
|
|
mux = devm_kzalloc(&pdev->dev, sizeof(*mux), GFP_KERNEL);
|
|
if (!mux) {
|
|
dev_err(&pdev->dev, "Cannot allocate i2c_mux_pinctrl\n");
|
|
ret = -ENOMEM;
|
|
goto err;
|
|
}
|
|
platform_set_drvdata(pdev, mux);
|
|
|
|
mux->dev = &pdev->dev;
|
|
|
|
mux->pdata = pdev->dev.platform_data;
|
|
if (!mux->pdata) {
|
|
ret = i2c_mux_pinctrl_parse_dt(mux, pdev);
|
|
if (ret < 0)
|
|
goto err;
|
|
}
|
|
if (!mux->pdata) {
|
|
dev_err(&pdev->dev, "Missing platform data\n");
|
|
ret = -ENODEV;
|
|
goto err;
|
|
}
|
|
|
|
mux->states = devm_kzalloc(&pdev->dev,
|
|
sizeof(*mux->states) * mux->pdata->bus_count,
|
|
GFP_KERNEL);
|
|
if (!mux->states) {
|
|
dev_err(&pdev->dev, "Cannot allocate states\n");
|
|
ret = -ENOMEM;
|
|
goto err;
|
|
}
|
|
|
|
mux->busses = devm_kzalloc(&pdev->dev,
|
|
sizeof(mux->busses) * mux->pdata->bus_count,
|
|
GFP_KERNEL);
|
|
if (!mux->states) {
|
|
dev_err(&pdev->dev, "Cannot allocate busses\n");
|
|
ret = -ENOMEM;
|
|
goto err;
|
|
}
|
|
|
|
mux->pinctrl = devm_pinctrl_get(&pdev->dev);
|
|
if (IS_ERR(mux->pinctrl)) {
|
|
ret = PTR_ERR(mux->pinctrl);
|
|
dev_err(&pdev->dev, "Cannot get pinctrl: %d\n", ret);
|
|
goto err;
|
|
}
|
|
for (i = 0; i < mux->pdata->bus_count; i++) {
|
|
mux->states[i] = pinctrl_lookup_state(mux->pinctrl,
|
|
mux->pdata->pinctrl_states[i]);
|
|
if (IS_ERR(mux->states[i])) {
|
|
ret = PTR_ERR(mux->states[i]);
|
|
dev_err(&pdev->dev,
|
|
"Cannot look up pinctrl state %s: %d\n",
|
|
mux->pdata->pinctrl_states[i], ret);
|
|
goto err;
|
|
}
|
|
}
|
|
if (mux->pdata->pinctrl_state_idle) {
|
|
mux->state_idle = pinctrl_lookup_state(mux->pinctrl,
|
|
mux->pdata->pinctrl_state_idle);
|
|
if (IS_ERR(mux->state_idle)) {
|
|
ret = PTR_ERR(mux->state_idle);
|
|
dev_err(&pdev->dev,
|
|
"Cannot look up pinctrl state %s: %d\n",
|
|
mux->pdata->pinctrl_state_idle, ret);
|
|
goto err;
|
|
}
|
|
|
|
deselect = i2c_mux_pinctrl_deselect;
|
|
} else {
|
|
deselect = NULL;
|
|
}
|
|
|
|
mux->parent = i2c_get_adapter(mux->pdata->parent_bus_num);
|
|
if (!mux->parent) {
|
|
dev_err(&pdev->dev, "Parent adapter (%d) not found\n",
|
|
mux->pdata->parent_bus_num);
|
|
ret = -ENODEV;
|
|
goto err;
|
|
}
|
|
|
|
for (i = 0; i < mux->pdata->bus_count; i++) {
|
|
u32 bus = mux->pdata->base_bus_num ?
|
|
(mux->pdata->base_bus_num + i) : 0;
|
|
|
|
mux->busses[i] = i2c_add_mux_adapter(mux->parent, &pdev->dev,
|
|
mux, bus, i,
|
|
i2c_mux_pinctrl_select,
|
|
deselect);
|
|
if (!mux->busses[i]) {
|
|
ret = -ENODEV;
|
|
dev_err(&pdev->dev, "Failed to add adapter %d\n", i);
|
|
goto err_del_adapter;
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
|
|
err_del_adapter:
|
|
for (; i > 0; i--)
|
|
i2c_del_mux_adapter(mux->busses[i - 1]);
|
|
i2c_put_adapter(mux->parent);
|
|
err:
|
|
return ret;
|
|
}
|
|
|
|
static int __devexit i2c_mux_pinctrl_remove(struct platform_device *pdev)
|
|
{
|
|
struct i2c_mux_pinctrl *mux = platform_get_drvdata(pdev);
|
|
int i;
|
|
|
|
for (i = 0; i < mux->pdata->bus_count; i++)
|
|
i2c_del_mux_adapter(mux->busses[i]);
|
|
|
|
i2c_put_adapter(mux->parent);
|
|
|
|
return 0;
|
|
}
|
|
|
|
#ifdef CONFIG_OF
|
|
static const struct of_device_id i2c_mux_pinctrl_of_match[] __devinitconst = {
|
|
{ .compatible = "i2c-mux-pinctrl", },
|
|
{},
|
|
};
|
|
MODULE_DEVICE_TABLE(of, i2c_mux_pinctrl_of_match);
|
|
#endif
|
|
|
|
static struct platform_driver i2c_mux_pinctrl_driver = {
|
|
.driver = {
|
|
.name = "i2c-mux-pinctrl",
|
|
.owner = THIS_MODULE,
|
|
.of_match_table = of_match_ptr(i2c_mux_pinctrl_of_match),
|
|
},
|
|
.probe = i2c_mux_pinctrl_probe,
|
|
.remove = __devexit_p(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");
|