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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * I2C multiplexer using pinctrl API4 *5 * Copyright (c) 2012, NVIDIA CORPORATION. All rights reserved.6 */7 8#include <linux/i2c.h>9#include <linux/i2c-mux.h>10#include <linux/module.h>11#include <linux/pinctrl/consumer.h>12#include <linux/platform_device.h>13#include <linux/slab.h>14#include <linux/of.h>15#include "../../pinctrl/core.h"16 17struct i2c_mux_pinctrl {18 struct pinctrl *pinctrl;19 struct pinctrl_state *states[];20};21 22static int i2c_mux_pinctrl_select(struct i2c_mux_core *muxc, u32 chan)23{24 struct i2c_mux_pinctrl *mux = i2c_mux_priv(muxc);25 26 return pinctrl_select_state(mux->pinctrl, mux->states[chan]);27}28 29static int i2c_mux_pinctrl_deselect(struct i2c_mux_core *muxc, u32 chan)30{31 return i2c_mux_pinctrl_select(muxc, muxc->num_adapters);32}33 34static struct i2c_adapter *i2c_mux_pinctrl_root_adapter(35 struct pinctrl_state *state)36{37 struct i2c_adapter *root = NULL;38 struct pinctrl_setting *setting;39 struct i2c_adapter *pin_root;40 41 list_for_each_entry(setting, &state->settings, node) {42 pin_root = i2c_root_adapter(setting->pctldev->dev);43 if (!pin_root)44 return NULL;45 if (!root)46 root = pin_root;47 else if (root != pin_root)48 return NULL;49 }50 51 return root;52}53 54static struct i2c_adapter *i2c_mux_pinctrl_parent_adapter(struct device *dev)55{56 struct device_node *np = dev->of_node;57 struct device_node *parent_np;58 struct i2c_adapter *parent;59 60 parent_np = of_parse_phandle(np, "i2c-parent", 0);61 if (!parent_np) {62 dev_err(dev, "Cannot parse i2c-parent\n");63 return ERR_PTR(-ENODEV);64 }65 parent = of_get_i2c_adapter_by_node(parent_np);66 of_node_put(parent_np);67 if (!parent)68 return ERR_PTR(-EPROBE_DEFER);69 70 return parent;71}72 73static int i2c_mux_pinctrl_probe(struct platform_device *pdev)74{75 struct device *dev = &pdev->dev;76 struct device_node *np = dev->of_node;77 struct i2c_mux_core *muxc;78 struct i2c_mux_pinctrl *mux;79 struct i2c_adapter *parent;80 struct i2c_adapter *root;81 int num_names, i, ret;82 const char *name;83 84 num_names = of_property_count_strings(np, "pinctrl-names");85 if (num_names < 0) {86 dev_err(dev, "Cannot parse pinctrl-names: %d\n",87 num_names);88 return num_names;89 }90 91 parent = i2c_mux_pinctrl_parent_adapter(dev);92 if (IS_ERR(parent))93 return PTR_ERR(parent);94 95 muxc = i2c_mux_alloc(parent, dev, num_names,96 struct_size(mux, states, num_names),97 0, i2c_mux_pinctrl_select, NULL);98 if (!muxc) {99 ret = -ENOMEM;100 goto err_put_parent;101 }102 mux = i2c_mux_priv(muxc);103 104 platform_set_drvdata(pdev, muxc);105 106 mux->pinctrl = devm_pinctrl_get(dev);107 if (IS_ERR(mux->pinctrl)) {108 ret = PTR_ERR(mux->pinctrl);109 dev_err(dev, "Cannot get pinctrl: %d\n", ret);110 goto err_put_parent;111 }112 113 for (i = 0; i < num_names; i++) {114 ret = of_property_read_string_index(np, "pinctrl-names", i,115 &name);116 if (ret < 0) {117 dev_err(dev, "Cannot parse pinctrl-names: %d\n", ret);118 goto err_put_parent;119 }120 121 mux->states[i] = pinctrl_lookup_state(mux->pinctrl, name);122 if (IS_ERR(mux->states[i])) {123 ret = PTR_ERR(mux->states[i]);124 dev_err(dev, "Cannot look up pinctrl state %s: %d\n",125 name, ret);126 goto err_put_parent;127 }128 129 if (strcmp(name, "idle"))130 continue;131 132 if (i != num_names - 1) {133 dev_err(dev, "idle state must be last\n");134 ret = -EINVAL;135 goto err_put_parent;136 }137 muxc->deselect = i2c_mux_pinctrl_deselect;138 }139 140 root = i2c_root_adapter(&muxc->parent->dev);141 142 muxc->mux_locked = true;143 for (i = 0; i < num_names; i++) {144 if (root != i2c_mux_pinctrl_root_adapter(mux->states[i])) {145 muxc->mux_locked = false;146 break;147 }148 }149 if (muxc->mux_locked)150 dev_info(dev, "mux-locked i2c mux\n");151 152 /* Do not add any adapter for the idle state (if it's there at all). */153 for (i = 0; i < num_names - !!muxc->deselect; i++) {154 ret = i2c_mux_add_adapter(muxc, 0, i);155 if (ret)156 goto err_del_adapter;157 }158 159 return 0;160 161err_del_adapter:162 i2c_mux_del_adapters(muxc);163err_put_parent:164 i2c_put_adapter(parent);165 166 return ret;167}168 169static void i2c_mux_pinctrl_remove(struct platform_device *pdev)170{171 struct i2c_mux_core *muxc = platform_get_drvdata(pdev);172 173 i2c_mux_del_adapters(muxc);174 i2c_put_adapter(muxc->parent);175}176 177static const struct of_device_id i2c_mux_pinctrl_of_match[] = {178 { .compatible = "i2c-mux-pinctrl", },179 {},180};181MODULE_DEVICE_TABLE(of, i2c_mux_pinctrl_of_match);182 183static struct platform_driver i2c_mux_pinctrl_driver = {184 .driver = {185 .name = "i2c-mux-pinctrl",186 .of_match_table = i2c_mux_pinctrl_of_match,187 },188 .probe = i2c_mux_pinctrl_probe,189 .remove_new = i2c_mux_pinctrl_remove,190};191module_platform_driver(i2c_mux_pinctrl_driver);192 193MODULE_DESCRIPTION("pinctrl-based I2C multiplexer driver");194MODULE_AUTHOR("Stephen Warren <swarren@nvidia.com>");195MODULE_LICENSE("GPL v2");196MODULE_ALIAS("platform:i2c-mux-pinctrl");197