687b81d083
I2C of helpers used to live in of_i2c.c but experience (from SPI) shows that it is much cleaner to have this in the core. This also removes a circular dependency between the helpers and the core, and so we can finally register child nodes in the core instead of doing this manually in each driver. So, fix the drivers and documentation, too. Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
279 lines
7 KiB
C
279 lines
7 KiB
C
/*
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* I2C multiplexer using pinctrl API
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*
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* Copyright (c) 2012, NVIDIA CORPORATION. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <linux/i2c.h>
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#include <linux/i2c-mux.h>
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/pinctrl/consumer.h>
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#include <linux/i2c-mux-pinctrl.h>
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#include <linux/platform_device.h>
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#include <linux/slab.h>
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struct i2c_mux_pinctrl {
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struct device *dev;
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struct i2c_mux_pinctrl_platform_data *pdata;
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struct pinctrl *pinctrl;
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struct pinctrl_state **states;
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struct pinctrl_state *state_idle;
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struct i2c_adapter *parent;
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struct i2c_adapter **busses;
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};
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static int i2c_mux_pinctrl_select(struct i2c_adapter *adap, void *data,
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u32 chan)
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{
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struct i2c_mux_pinctrl *mux = data;
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return pinctrl_select_state(mux->pinctrl, mux->states[chan]);
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}
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static int i2c_mux_pinctrl_deselect(struct i2c_adapter *adap, void *data,
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u32 chan)
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{
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struct i2c_mux_pinctrl *mux = data;
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return pinctrl_select_state(mux->pinctrl, mux->state_idle);
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}
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#ifdef CONFIG_OF
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static int i2c_mux_pinctrl_parse_dt(struct i2c_mux_pinctrl *mux,
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struct platform_device *pdev)
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{
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struct device_node *np = pdev->dev.of_node;
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int num_names, i, ret;
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struct device_node *adapter_np;
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struct i2c_adapter *adapter;
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if (!np)
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return 0;
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mux->pdata = devm_kzalloc(&pdev->dev, sizeof(*mux->pdata), GFP_KERNEL);
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if (!mux->pdata) {
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dev_err(mux->dev,
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"Cannot allocate i2c_mux_pinctrl_platform_data\n");
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return -ENOMEM;
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}
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num_names = of_property_count_strings(np, "pinctrl-names");
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if (num_names < 0) {
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dev_err(mux->dev, "Cannot parse pinctrl-names: %d\n",
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num_names);
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return num_names;
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}
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mux->pdata->pinctrl_states = devm_kzalloc(&pdev->dev,
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sizeof(*mux->pdata->pinctrl_states) * num_names,
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GFP_KERNEL);
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if (!mux->pdata->pinctrl_states) {
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dev_err(mux->dev, "Cannot allocate pinctrl_states\n");
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return -ENOMEM;
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}
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for (i = 0; i < num_names; i++) {
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ret = of_property_read_string_index(np, "pinctrl-names", i,
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&mux->pdata->pinctrl_states[mux->pdata->bus_count]);
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if (ret < 0) {
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dev_err(mux->dev, "Cannot parse pinctrl-names: %d\n",
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ret);
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return ret;
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}
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if (!strcmp(mux->pdata->pinctrl_states[mux->pdata->bus_count],
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"idle")) {
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if (i != num_names - 1) {
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dev_err(mux->dev, "idle state must be last\n");
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return -EINVAL;
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}
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mux->pdata->pinctrl_state_idle = "idle";
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} else {
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mux->pdata->bus_count++;
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}
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}
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adapter_np = of_parse_phandle(np, "i2c-parent", 0);
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if (!adapter_np) {
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dev_err(mux->dev, "Cannot parse i2c-parent\n");
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return -ENODEV;
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}
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adapter = of_find_i2c_adapter_by_node(adapter_np);
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if (!adapter) {
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dev_err(mux->dev, "Cannot find parent bus\n");
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return -ENODEV;
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}
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mux->pdata->parent_bus_num = i2c_adapter_id(adapter);
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put_device(&adapter->dev);
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return 0;
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}
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#else
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static inline int i2c_mux_pinctrl_parse_dt(struct i2c_mux_pinctrl *mux,
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struct platform_device *pdev)
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{
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return 0;
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}
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#endif
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static int i2c_mux_pinctrl_probe(struct platform_device *pdev)
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{
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struct i2c_mux_pinctrl *mux;
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int (*deselect)(struct i2c_adapter *, void *, u32);
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int i, ret;
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mux = devm_kzalloc(&pdev->dev, sizeof(*mux), GFP_KERNEL);
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if (!mux) {
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dev_err(&pdev->dev, "Cannot allocate i2c_mux_pinctrl\n");
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ret = -ENOMEM;
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goto err;
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}
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platform_set_drvdata(pdev, mux);
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mux->dev = &pdev->dev;
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mux->pdata = dev_get_platdata(&pdev->dev);
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if (!mux->pdata) {
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ret = i2c_mux_pinctrl_parse_dt(mux, pdev);
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if (ret < 0)
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goto err;
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}
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if (!mux->pdata) {
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dev_err(&pdev->dev, "Missing platform data\n");
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ret = -ENODEV;
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goto err;
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}
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mux->states = devm_kzalloc(&pdev->dev,
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sizeof(*mux->states) * mux->pdata->bus_count,
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GFP_KERNEL);
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if (!mux->states) {
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dev_err(&pdev->dev, "Cannot allocate states\n");
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ret = -ENOMEM;
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goto err;
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}
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mux->busses = devm_kzalloc(&pdev->dev,
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sizeof(*mux->busses) * mux->pdata->bus_count,
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GFP_KERNEL);
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if (!mux->busses) {
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dev_err(&pdev->dev, "Cannot allocate busses\n");
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ret = -ENOMEM;
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goto err;
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}
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mux->pinctrl = devm_pinctrl_get(&pdev->dev);
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if (IS_ERR(mux->pinctrl)) {
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ret = PTR_ERR(mux->pinctrl);
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dev_err(&pdev->dev, "Cannot get pinctrl: %d\n", ret);
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goto err;
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}
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for (i = 0; i < mux->pdata->bus_count; i++) {
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mux->states[i] = pinctrl_lookup_state(mux->pinctrl,
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mux->pdata->pinctrl_states[i]);
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if (IS_ERR(mux->states[i])) {
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ret = PTR_ERR(mux->states[i]);
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dev_err(&pdev->dev,
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"Cannot look up pinctrl state %s: %d\n",
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mux->pdata->pinctrl_states[i], ret);
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goto err;
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}
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}
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if (mux->pdata->pinctrl_state_idle) {
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mux->state_idle = pinctrl_lookup_state(mux->pinctrl,
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mux->pdata->pinctrl_state_idle);
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if (IS_ERR(mux->state_idle)) {
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ret = PTR_ERR(mux->state_idle);
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dev_err(&pdev->dev,
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"Cannot look up pinctrl state %s: %d\n",
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mux->pdata->pinctrl_state_idle, ret);
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goto err;
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}
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deselect = i2c_mux_pinctrl_deselect;
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} else {
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deselect = NULL;
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}
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mux->parent = i2c_get_adapter(mux->pdata->parent_bus_num);
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if (!mux->parent) {
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dev_err(&pdev->dev, "Parent adapter (%d) not found\n",
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mux->pdata->parent_bus_num);
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ret = -ENODEV;
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goto err;
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}
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for (i = 0; i < mux->pdata->bus_count; i++) {
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u32 bus = mux->pdata->base_bus_num ?
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(mux->pdata->base_bus_num + i) : 0;
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mux->busses[i] = i2c_add_mux_adapter(mux->parent, &pdev->dev,
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mux, bus, i, 0,
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i2c_mux_pinctrl_select,
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deselect);
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if (!mux->busses[i]) {
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ret = -ENODEV;
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dev_err(&pdev->dev, "Failed to add adapter %d\n", i);
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goto err_del_adapter;
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}
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}
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return 0;
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err_del_adapter:
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for (; i > 0; i--)
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i2c_del_mux_adapter(mux->busses[i - 1]);
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i2c_put_adapter(mux->parent);
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err:
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return ret;
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}
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static int i2c_mux_pinctrl_remove(struct platform_device *pdev)
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{
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struct i2c_mux_pinctrl *mux = platform_get_drvdata(pdev);
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int i;
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for (i = 0; i < mux->pdata->bus_count; i++)
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i2c_del_mux_adapter(mux->busses[i]);
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i2c_put_adapter(mux->parent);
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return 0;
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}
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#ifdef CONFIG_OF
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static const struct of_device_id i2c_mux_pinctrl_of_match[] = {
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{ .compatible = "i2c-mux-pinctrl", },
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{},
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};
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MODULE_DEVICE_TABLE(of, i2c_mux_pinctrl_of_match);
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#endif
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static struct platform_driver i2c_mux_pinctrl_driver = {
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.driver = {
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.name = "i2c-mux-pinctrl",
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.owner = THIS_MODULE,
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.of_match_table = of_match_ptr(i2c_mux_pinctrl_of_match),
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},
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.probe = i2c_mux_pinctrl_probe,
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.remove = i2c_mux_pinctrl_remove,
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};
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module_platform_driver(i2c_mux_pinctrl_driver);
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MODULE_DESCRIPTION("pinctrl-based I2C multiplexer driver");
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MODULE_AUTHOR("Stephen Warren <swarren@nvidia.com>");
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MODULE_LICENSE("GPL v2");
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MODULE_ALIAS("platform:i2c-mux-pinctrl");
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