1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * General Purpose I2C multiplexer 4 * 5 * Copyright (C) 2017 Axentia Technologies AB 6 * 7 * Author: Peter Rosin <peda@axentia.se> 8 */ 9 10 #include <linux/i2c.h> 11 #include <linux/i2c-mux.h> 12 #include <linux/module.h> 13 #include <linux/mux/consumer.h> 14 #include <linux/of_device.h> 15 #include <linux/platform_device.h> 16 17 struct mux { 18 struct mux_control *control; 19 20 bool do_not_deselect; 21 }; 22 23 static int i2c_mux_select(struct i2c_mux_core *muxc, u32 chan) 24 { 25 struct mux *mux = i2c_mux_priv(muxc); 26 int ret; 27 28 ret = mux_control_select(mux->control, chan); 29 mux->do_not_deselect = ret < 0; 30 31 return ret; 32 } 33 34 static int i2c_mux_deselect(struct i2c_mux_core *muxc, u32 chan) 35 { 36 struct mux *mux = i2c_mux_priv(muxc); 37 38 if (mux->do_not_deselect) 39 return 0; 40 41 return mux_control_deselect(mux->control); 42 } 43 44 static struct i2c_adapter *mux_parent_adapter(struct device *dev) 45 { 46 struct device_node *np = dev->of_node; 47 struct device_node *parent_np; 48 struct i2c_adapter *parent; 49 50 parent_np = of_parse_phandle(np, "i2c-parent", 0); 51 if (!parent_np) { 52 dev_err(dev, "Cannot parse i2c-parent\n"); 53 return ERR_PTR(-ENODEV); 54 } 55 parent = of_find_i2c_adapter_by_node(parent_np); 56 of_node_put(parent_np); 57 if (!parent) 58 return ERR_PTR(-EPROBE_DEFER); 59 60 return parent; 61 } 62 63 static const struct of_device_id i2c_mux_of_match[] = { 64 { .compatible = "i2c-mux", }, 65 {}, 66 }; 67 MODULE_DEVICE_TABLE(of, i2c_mux_of_match); 68 69 static int i2c_mux_probe(struct platform_device *pdev) 70 { 71 struct device *dev = &pdev->dev; 72 struct device_node *np = dev->of_node; 73 struct device_node *child; 74 struct i2c_mux_core *muxc; 75 struct mux *mux; 76 struct i2c_adapter *parent; 77 int children; 78 int ret; 79 80 if (!np) 81 return -ENODEV; 82 83 mux = devm_kzalloc(dev, sizeof(*mux), GFP_KERNEL); 84 if (!mux) 85 return -ENOMEM; 86 87 mux->control = devm_mux_control_get(dev, NULL); 88 if (IS_ERR(mux->control)) { 89 if (PTR_ERR(mux->control) != -EPROBE_DEFER) 90 dev_err(dev, "failed to get control-mux\n"); 91 return PTR_ERR(mux->control); 92 } 93 94 parent = mux_parent_adapter(dev); 95 if (IS_ERR(parent)) { 96 if (PTR_ERR(parent) != -EPROBE_DEFER) 97 dev_err(dev, "failed to get i2c-parent adapter\n"); 98 return PTR_ERR(parent); 99 } 100 101 children = of_get_child_count(np); 102 103 muxc = i2c_mux_alloc(parent, dev, children, 0, 0, 104 i2c_mux_select, i2c_mux_deselect); 105 if (!muxc) { 106 ret = -ENOMEM; 107 goto err_parent; 108 } 109 muxc->priv = mux; 110 111 platform_set_drvdata(pdev, muxc); 112 113 muxc->mux_locked = of_property_read_bool(np, "mux-locked"); 114 115 for_each_child_of_node(np, child) { 116 u32 chan; 117 118 ret = of_property_read_u32(child, "reg", &chan); 119 if (ret < 0) { 120 dev_err(dev, "no reg property for node '%pOFn'\n", 121 child); 122 goto err_children; 123 } 124 125 if (chan >= mux_control_states(mux->control)) { 126 dev_err(dev, "invalid reg %u\n", chan); 127 ret = -EINVAL; 128 goto err_children; 129 } 130 131 ret = i2c_mux_add_adapter(muxc, 0, chan, 0); 132 if (ret) 133 goto err_children; 134 } 135 136 dev_info(dev, "%d-port mux on %s adapter\n", children, parent->name); 137 138 return 0; 139 140 err_children: 141 i2c_mux_del_adapters(muxc); 142 err_parent: 143 i2c_put_adapter(parent); 144 145 return ret; 146 } 147 148 static int i2c_mux_remove(struct platform_device *pdev) 149 { 150 struct i2c_mux_core *muxc = platform_get_drvdata(pdev); 151 152 i2c_mux_del_adapters(muxc); 153 i2c_put_adapter(muxc->parent); 154 155 return 0; 156 } 157 158 static struct platform_driver i2c_mux_driver = { 159 .probe = i2c_mux_probe, 160 .remove = i2c_mux_remove, 161 .driver = { 162 .name = "i2c-mux-gpmux", 163 .of_match_table = i2c_mux_of_match, 164 }, 165 }; 166 module_platform_driver(i2c_mux_driver); 167 168 MODULE_DESCRIPTION("General Purpose I2C multiplexer driver"); 169 MODULE_AUTHOR("Peter Rosin <peda@axentia.se>"); 170 MODULE_LICENSE("GPL v2"); 171