1*ac8498f0SPeter Rosin /* 2*ac8498f0SPeter Rosin * General Purpose I2C multiplexer 3*ac8498f0SPeter Rosin * 4*ac8498f0SPeter Rosin * Copyright (C) 2017 Axentia Technologies AB 5*ac8498f0SPeter Rosin * 6*ac8498f0SPeter Rosin * Author: Peter Rosin <peda@axentia.se> 7*ac8498f0SPeter Rosin * 8*ac8498f0SPeter Rosin * This program is free software; you can redistribute it and/or modify 9*ac8498f0SPeter Rosin * it under the terms of the GNU General Public License version 2 as 10*ac8498f0SPeter Rosin * published by the Free Software Foundation. 11*ac8498f0SPeter Rosin */ 12*ac8498f0SPeter Rosin 13*ac8498f0SPeter Rosin #include <linux/i2c.h> 14*ac8498f0SPeter Rosin #include <linux/i2c-mux.h> 15*ac8498f0SPeter Rosin #include <linux/module.h> 16*ac8498f0SPeter Rosin #include <linux/mux/consumer.h> 17*ac8498f0SPeter Rosin #include <linux/of_device.h> 18*ac8498f0SPeter Rosin #include <linux/platform_device.h> 19*ac8498f0SPeter Rosin 20*ac8498f0SPeter Rosin struct mux { 21*ac8498f0SPeter Rosin struct mux_control *control; 22*ac8498f0SPeter Rosin 23*ac8498f0SPeter Rosin bool do_not_deselect; 24*ac8498f0SPeter Rosin }; 25*ac8498f0SPeter Rosin 26*ac8498f0SPeter Rosin static int i2c_mux_select(struct i2c_mux_core *muxc, u32 chan) 27*ac8498f0SPeter Rosin { 28*ac8498f0SPeter Rosin struct mux *mux = i2c_mux_priv(muxc); 29*ac8498f0SPeter Rosin int ret; 30*ac8498f0SPeter Rosin 31*ac8498f0SPeter Rosin ret = mux_control_select(mux->control, chan); 32*ac8498f0SPeter Rosin mux->do_not_deselect = ret < 0; 33*ac8498f0SPeter Rosin 34*ac8498f0SPeter Rosin return ret; 35*ac8498f0SPeter Rosin } 36*ac8498f0SPeter Rosin 37*ac8498f0SPeter Rosin static int i2c_mux_deselect(struct i2c_mux_core *muxc, u32 chan) 38*ac8498f0SPeter Rosin { 39*ac8498f0SPeter Rosin struct mux *mux = i2c_mux_priv(muxc); 40*ac8498f0SPeter Rosin 41*ac8498f0SPeter Rosin if (mux->do_not_deselect) 42*ac8498f0SPeter Rosin return 0; 43*ac8498f0SPeter Rosin 44*ac8498f0SPeter Rosin return mux_control_deselect(mux->control); 45*ac8498f0SPeter Rosin } 46*ac8498f0SPeter Rosin 47*ac8498f0SPeter Rosin static struct i2c_adapter *mux_parent_adapter(struct device *dev) 48*ac8498f0SPeter Rosin { 49*ac8498f0SPeter Rosin struct device_node *np = dev->of_node; 50*ac8498f0SPeter Rosin struct device_node *parent_np; 51*ac8498f0SPeter Rosin struct i2c_adapter *parent; 52*ac8498f0SPeter Rosin 53*ac8498f0SPeter Rosin parent_np = of_parse_phandle(np, "i2c-parent", 0); 54*ac8498f0SPeter Rosin if (!parent_np) { 55*ac8498f0SPeter Rosin dev_err(dev, "Cannot parse i2c-parent\n"); 56*ac8498f0SPeter Rosin return ERR_PTR(-ENODEV); 57*ac8498f0SPeter Rosin } 58*ac8498f0SPeter Rosin parent = of_find_i2c_adapter_by_node(parent_np); 59*ac8498f0SPeter Rosin of_node_put(parent_np); 60*ac8498f0SPeter Rosin if (!parent) 61*ac8498f0SPeter Rosin return ERR_PTR(-EPROBE_DEFER); 62*ac8498f0SPeter Rosin 63*ac8498f0SPeter Rosin return parent; 64*ac8498f0SPeter Rosin } 65*ac8498f0SPeter Rosin 66*ac8498f0SPeter Rosin static const struct of_device_id i2c_mux_of_match[] = { 67*ac8498f0SPeter Rosin { .compatible = "i2c-mux", }, 68*ac8498f0SPeter Rosin {}, 69*ac8498f0SPeter Rosin }; 70*ac8498f0SPeter Rosin MODULE_DEVICE_TABLE(of, i2c_mux_of_match); 71*ac8498f0SPeter Rosin 72*ac8498f0SPeter Rosin static int i2c_mux_probe(struct platform_device *pdev) 73*ac8498f0SPeter Rosin { 74*ac8498f0SPeter Rosin struct device *dev = &pdev->dev; 75*ac8498f0SPeter Rosin struct device_node *np = dev->of_node; 76*ac8498f0SPeter Rosin struct device_node *child; 77*ac8498f0SPeter Rosin struct i2c_mux_core *muxc; 78*ac8498f0SPeter Rosin struct mux *mux; 79*ac8498f0SPeter Rosin struct i2c_adapter *parent; 80*ac8498f0SPeter Rosin int children; 81*ac8498f0SPeter Rosin int ret; 82*ac8498f0SPeter Rosin 83*ac8498f0SPeter Rosin if (!np) 84*ac8498f0SPeter Rosin return -ENODEV; 85*ac8498f0SPeter Rosin 86*ac8498f0SPeter Rosin mux = devm_kzalloc(dev, sizeof(*mux), GFP_KERNEL); 87*ac8498f0SPeter Rosin if (!mux) 88*ac8498f0SPeter Rosin return -ENOMEM; 89*ac8498f0SPeter Rosin 90*ac8498f0SPeter Rosin mux->control = devm_mux_control_get(dev, NULL); 91*ac8498f0SPeter Rosin if (IS_ERR(mux->control)) { 92*ac8498f0SPeter Rosin if (PTR_ERR(mux->control) != -EPROBE_DEFER) 93*ac8498f0SPeter Rosin dev_err(dev, "failed to get control-mux\n"); 94*ac8498f0SPeter Rosin return PTR_ERR(mux->control); 95*ac8498f0SPeter Rosin } 96*ac8498f0SPeter Rosin 97*ac8498f0SPeter Rosin parent = mux_parent_adapter(dev); 98*ac8498f0SPeter Rosin if (IS_ERR(parent)) { 99*ac8498f0SPeter Rosin if (PTR_ERR(parent) != -EPROBE_DEFER) 100*ac8498f0SPeter Rosin dev_err(dev, "failed to get i2c-parent adapter\n"); 101*ac8498f0SPeter Rosin return PTR_ERR(parent); 102*ac8498f0SPeter Rosin } 103*ac8498f0SPeter Rosin 104*ac8498f0SPeter Rosin children = of_get_child_count(np); 105*ac8498f0SPeter Rosin 106*ac8498f0SPeter Rosin muxc = i2c_mux_alloc(parent, dev, children, 0, 0, 107*ac8498f0SPeter Rosin i2c_mux_select, i2c_mux_deselect); 108*ac8498f0SPeter Rosin if (!muxc) { 109*ac8498f0SPeter Rosin ret = -ENOMEM; 110*ac8498f0SPeter Rosin goto err_parent; 111*ac8498f0SPeter Rosin } 112*ac8498f0SPeter Rosin muxc->priv = mux; 113*ac8498f0SPeter Rosin 114*ac8498f0SPeter Rosin platform_set_drvdata(pdev, muxc); 115*ac8498f0SPeter Rosin 116*ac8498f0SPeter Rosin muxc->mux_locked = of_property_read_bool(np, "mux-locked"); 117*ac8498f0SPeter Rosin 118*ac8498f0SPeter Rosin for_each_child_of_node(np, child) { 119*ac8498f0SPeter Rosin u32 chan; 120*ac8498f0SPeter Rosin 121*ac8498f0SPeter Rosin ret = of_property_read_u32(child, "reg", &chan); 122*ac8498f0SPeter Rosin if (ret < 0) { 123*ac8498f0SPeter Rosin dev_err(dev, "no reg property for node '%s'\n", 124*ac8498f0SPeter Rosin child->name); 125*ac8498f0SPeter Rosin goto err_children; 126*ac8498f0SPeter Rosin } 127*ac8498f0SPeter Rosin 128*ac8498f0SPeter Rosin if (chan >= mux_control_states(mux->control)) { 129*ac8498f0SPeter Rosin dev_err(dev, "invalid reg %u\n", chan); 130*ac8498f0SPeter Rosin ret = -EINVAL; 131*ac8498f0SPeter Rosin goto err_children; 132*ac8498f0SPeter Rosin } 133*ac8498f0SPeter Rosin 134*ac8498f0SPeter Rosin ret = i2c_mux_add_adapter(muxc, 0, chan, 0); 135*ac8498f0SPeter Rosin if (ret) 136*ac8498f0SPeter Rosin goto err_children; 137*ac8498f0SPeter Rosin } 138*ac8498f0SPeter Rosin 139*ac8498f0SPeter Rosin dev_info(dev, "%d-port mux on %s adapter\n", children, parent->name); 140*ac8498f0SPeter Rosin 141*ac8498f0SPeter Rosin return 0; 142*ac8498f0SPeter Rosin 143*ac8498f0SPeter Rosin err_children: 144*ac8498f0SPeter Rosin i2c_mux_del_adapters(muxc); 145*ac8498f0SPeter Rosin err_parent: 146*ac8498f0SPeter Rosin i2c_put_adapter(parent); 147*ac8498f0SPeter Rosin 148*ac8498f0SPeter Rosin return ret; 149*ac8498f0SPeter Rosin } 150*ac8498f0SPeter Rosin 151*ac8498f0SPeter Rosin static int i2c_mux_remove(struct platform_device *pdev) 152*ac8498f0SPeter Rosin { 153*ac8498f0SPeter Rosin struct i2c_mux_core *muxc = platform_get_drvdata(pdev); 154*ac8498f0SPeter Rosin 155*ac8498f0SPeter Rosin i2c_mux_del_adapters(muxc); 156*ac8498f0SPeter Rosin i2c_put_adapter(muxc->parent); 157*ac8498f0SPeter Rosin 158*ac8498f0SPeter Rosin return 0; 159*ac8498f0SPeter Rosin } 160*ac8498f0SPeter Rosin 161*ac8498f0SPeter Rosin static struct platform_driver i2c_mux_driver = { 162*ac8498f0SPeter Rosin .probe = i2c_mux_probe, 163*ac8498f0SPeter Rosin .remove = i2c_mux_remove, 164*ac8498f0SPeter Rosin .driver = { 165*ac8498f0SPeter Rosin .name = "i2c-mux-gpmux", 166*ac8498f0SPeter Rosin .of_match_table = i2c_mux_of_match, 167*ac8498f0SPeter Rosin }, 168*ac8498f0SPeter Rosin }; 169*ac8498f0SPeter Rosin module_platform_driver(i2c_mux_driver); 170*ac8498f0SPeter Rosin 171*ac8498f0SPeter Rosin MODULE_DESCRIPTION("General Purpose I2C multiplexer driver"); 172*ac8498f0SPeter Rosin MODULE_AUTHOR("Peter Rosin <peda@axentia.se>"); 173*ac8498f0SPeter Rosin MODULE_LICENSE("GPL v2"); 174