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278 lines
7.0 KiB
278 lines
7.0 KiB
/* |
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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/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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#include <linux/of.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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of_node_put(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 -EPROBE_DEFER; |
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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 = -EPROBE_DEFER; |
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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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.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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