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166 lines
3.5 KiB
166 lines
3.5 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* General Purpose I2C multiplexer |
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* |
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* Copyright (C) 2017 Axentia Technologies AB |
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* |
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* Author: Peter Rosin <[email protected]> |
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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/mux/consumer.h> |
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#include <linux/of_device.h> |
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#include <linux/platform_device.h> |
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struct mux { |
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struct mux_control *control; |
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bool do_not_deselect; |
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}; |
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static int i2c_mux_select(struct i2c_mux_core *muxc, u32 chan) |
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{ |
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struct mux *mux = i2c_mux_priv(muxc); |
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int ret; |
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ret = mux_control_select(mux->control, chan); |
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mux->do_not_deselect = ret < 0; |
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return ret; |
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} |
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static int i2c_mux_deselect(struct i2c_mux_core *muxc, u32 chan) |
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{ |
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struct mux *mux = i2c_mux_priv(muxc); |
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if (mux->do_not_deselect) |
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return 0; |
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return mux_control_deselect(mux->control); |
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} |
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static struct i2c_adapter *mux_parent_adapter(struct device *dev) |
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{ |
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struct device_node *np = dev->of_node; |
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struct device_node *parent_np; |
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struct i2c_adapter *parent; |
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parent_np = of_parse_phandle(np, "i2c-parent", 0); |
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if (!parent_np) { |
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dev_err(dev, "Cannot parse i2c-parent\n"); |
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return ERR_PTR(-ENODEV); |
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} |
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parent = of_find_i2c_adapter_by_node(parent_np); |
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of_node_put(parent_np); |
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if (!parent) |
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return ERR_PTR(-EPROBE_DEFER); |
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return parent; |
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} |
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static const struct of_device_id i2c_mux_of_match[] = { |
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{ .compatible = "i2c-mux", }, |
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{}, |
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}; |
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MODULE_DEVICE_TABLE(of, i2c_mux_of_match); |
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static int i2c_mux_probe(struct platform_device *pdev) |
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{ |
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struct device *dev = &pdev->dev; |
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struct device_node *np = dev->of_node; |
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struct device_node *child; |
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struct i2c_mux_core *muxc; |
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struct mux *mux; |
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struct i2c_adapter *parent; |
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int children; |
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int ret; |
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if (!np) |
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return -ENODEV; |
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mux = devm_kzalloc(dev, sizeof(*mux), GFP_KERNEL); |
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if (!mux) |
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return -ENOMEM; |
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mux->control = devm_mux_control_get(dev, NULL); |
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if (IS_ERR(mux->control)) |
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return dev_err_probe(dev, PTR_ERR(mux->control), |
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"failed to get control-mux\n"); |
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parent = mux_parent_adapter(dev); |
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if (IS_ERR(parent)) |
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return dev_err_probe(dev, PTR_ERR(parent), |
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"failed to get i2c-parent adapter\n"); |
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children = of_get_child_count(np); |
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muxc = i2c_mux_alloc(parent, dev, children, 0, 0, |
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i2c_mux_select, i2c_mux_deselect); |
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if (!muxc) { |
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ret = -ENOMEM; |
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goto err_parent; |
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} |
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muxc->priv = mux; |
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platform_set_drvdata(pdev, muxc); |
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muxc->mux_locked = of_property_read_bool(np, "mux-locked"); |
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for_each_child_of_node(np, child) { |
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u32 chan; |
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ret = of_property_read_u32(child, "reg", &chan); |
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if (ret < 0) { |
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dev_err(dev, "no reg property for node '%pOFn'\n", |
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child); |
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goto err_children; |
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} |
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if (chan >= mux_control_states(mux->control)) { |
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dev_err(dev, "invalid reg %u\n", chan); |
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ret = -EINVAL; |
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goto err_children; |
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} |
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ret = i2c_mux_add_adapter(muxc, 0, chan, 0); |
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if (ret) |
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goto err_children; |
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} |
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dev_info(dev, "%d-port mux on %s adapter\n", children, parent->name); |
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return 0; |
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err_children: |
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i2c_mux_del_adapters(muxc); |
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err_parent: |
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i2c_put_adapter(parent); |
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return ret; |
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} |
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static int i2c_mux_remove(struct platform_device *pdev) |
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{ |
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struct i2c_mux_core *muxc = platform_get_drvdata(pdev); |
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i2c_mux_del_adapters(muxc); |
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i2c_put_adapter(muxc->parent); |
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return 0; |
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} |
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static struct platform_driver i2c_mux_driver = { |
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.probe = i2c_mux_probe, |
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.remove = i2c_mux_remove, |
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.driver = { |
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.name = "i2c-mux-gpmux", |
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.of_match_table = i2c_mux_of_match, |
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}, |
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}; |
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module_platform_driver(i2c_mux_driver); |
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MODULE_DESCRIPTION("General Purpose I2C multiplexer driver"); |
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MODULE_AUTHOR("Peter Rosin <[email protected]>"); |
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MODULE_LICENSE("GPL v2");
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