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198 lines
4.7 KiB
198 lines
4.7 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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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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#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/platform_device.h> |
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#include <linux/slab.h> |
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#include <linux/of.h> |
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#include "../../pinctrl/core.h" |
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struct i2c_mux_pinctrl { |
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struct pinctrl *pinctrl; |
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struct pinctrl_state *states[]; |
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}; |
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static int i2c_mux_pinctrl_select(struct i2c_mux_core *muxc, u32 chan) |
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{ |
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struct i2c_mux_pinctrl *mux = i2c_mux_priv(muxc); |
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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_mux_core *muxc, u32 chan) |
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{ |
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return i2c_mux_pinctrl_select(muxc, muxc->num_adapters); |
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} |
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static struct i2c_adapter *i2c_mux_pinctrl_root_adapter( |
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struct pinctrl_state *state) |
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{ |
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struct i2c_adapter *root = NULL; |
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struct pinctrl_setting *setting; |
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struct i2c_adapter *pin_root; |
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list_for_each_entry(setting, &state->settings, node) { |
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pin_root = i2c_root_adapter(setting->pctldev->dev); |
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if (!pin_root) |
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return NULL; |
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if (!root) |
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root = pin_root; |
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else if (root != pin_root) |
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return NULL; |
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} |
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return root; |
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} |
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static struct i2c_adapter *i2c_mux_pinctrl_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 int i2c_mux_pinctrl_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 i2c_mux_core *muxc; |
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struct i2c_mux_pinctrl *mux; |
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struct i2c_adapter *parent; |
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struct i2c_adapter *root; |
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int num_names, i, ret; |
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const char *name; |
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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(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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parent = i2c_mux_pinctrl_parent_adapter(dev); |
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if (IS_ERR(parent)) |
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return PTR_ERR(parent); |
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muxc = i2c_mux_alloc(parent, dev, num_names, |
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struct_size(mux, states, num_names), |
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0, i2c_mux_pinctrl_select, NULL); |
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if (!muxc) { |
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ret = -ENOMEM; |
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goto err_put_parent; |
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} |
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mux = i2c_mux_priv(muxc); |
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platform_set_drvdata(pdev, muxc); |
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mux->pinctrl = devm_pinctrl_get(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(dev, "Cannot get pinctrl: %d\n", ret); |
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goto err_put_parent; |
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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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&name); |
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if (ret < 0) { |
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dev_err(dev, "Cannot parse pinctrl-names: %d\n", ret); |
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goto err_put_parent; |
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} |
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mux->states[i] = pinctrl_lookup_state(mux->pinctrl, name); |
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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(dev, "Cannot look up pinctrl state %s: %d\n", |
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name, ret); |
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goto err_put_parent; |
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} |
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if (strcmp(name, "idle")) |
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continue; |
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if (i != num_names - 1) { |
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dev_err(dev, "idle state must be last\n"); |
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ret = -EINVAL; |
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goto err_put_parent; |
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} |
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muxc->deselect = i2c_mux_pinctrl_deselect; |
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} |
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root = i2c_root_adapter(&muxc->parent->dev); |
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muxc->mux_locked = true; |
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for (i = 0; i < num_names; i++) { |
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if (root != i2c_mux_pinctrl_root_adapter(mux->states[i])) { |
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muxc->mux_locked = false; |
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break; |
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} |
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} |
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if (muxc->mux_locked) |
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dev_info(dev, "mux-locked i2c mux\n"); |
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/* Do not add any adapter for the idle state (if it's there at all). */ |
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for (i = 0; i < num_names - !!muxc->deselect; i++) { |
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ret = i2c_mux_add_adapter(muxc, 0, i, 0); |
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if (ret) |
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goto err_del_adapter; |
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} |
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return 0; |
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err_del_adapter: |
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i2c_mux_del_adapters(muxc); |
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err_put_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_pinctrl_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 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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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 <[email protected]>"); |
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MODULE_LICENSE("GPL v2"); |
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MODULE_ALIAS("platform:i2c-mux-pinctrl");
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