Thomas Gleixner | d2912cb | 2019-06-04 10:11:33 +0200 | [diff] [blame^] | 1 | // SPDX-License-Identifier: GPL-2.0-only |
Peter Rosin | ac8498f | 2017-05-14 21:51:12 +0200 | [diff] [blame] | 2 | /* |
| 3 | * General Purpose I2C multiplexer |
| 4 | * |
| 5 | * Copyright (C) 2017 Axentia Technologies AB |
| 6 | * |
| 7 | * Author: Peter Rosin <peda@axentia.se> |
Peter Rosin | ac8498f | 2017-05-14 21:51:12 +0200 | [diff] [blame] | 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) { |
Rob Herring | 49d54ab | 2018-09-28 17:49:47 -0500 | [diff] [blame] | 120 | dev_err(dev, "no reg property for node '%pOFn'\n", |
| 121 | child); |
Peter Rosin | ac8498f | 2017-05-14 21:51:12 +0200 | [diff] [blame] | 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"); |