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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 | // SPDX-License-Identifier: GPL-2.0+ /* MDIO bus multiplexer using kernel multiplexer subsystem * * Copyright 2019 NXP */ #include <linux/mdio-mux.h> #include <linux/module.h> #include <linux/mux/consumer.h> #include <linux/platform_device.h> struct mdio_mux_multiplexer_state { struct mux_control *muxc; bool do_deselect; void *mux_handle; }; /** * mdio_mux_multiplexer_switch_fn - This function is called by the mdio-mux * layer when it thinks the mdio bus * multiplexer needs to switch. * @current_child: current value of the mux register. * @desired_child: value of the 'reg' property of the target child MDIO node. * @data: Private data used by this switch_fn passed to mdio_mux_init function * via mdio_mux_init(.., .., .., .., data, ..). * * The first time this function is called, current_child == -1. * If current_child == desired_child, then the mux is already set to the * correct bus. */ static int mdio_mux_multiplexer_switch_fn(int current_child, int desired_child, void *data) { struct platform_device *pdev; struct mdio_mux_multiplexer_state *s; int ret = 0; pdev = (struct platform_device *)data; s = platform_get_drvdata(pdev); if (!(current_child ^ desired_child)) return 0; if (s->do_deselect) ret = mux_control_deselect(s->muxc); if (ret) { dev_err(&pdev->dev, "mux_control_deselect failed in %s: %d\n", __func__, ret); return ret; } ret = mux_control_select(s->muxc, desired_child); if (!ret) { dev_dbg(&pdev->dev, "%s %d -> %d\n", __func__, current_child, desired_child); s->do_deselect = true; } else { s->do_deselect = false; } return ret; } static int mdio_mux_multiplexer_probe(struct platform_device *pdev) { struct device *dev = &pdev->dev; struct mdio_mux_multiplexer_state *s; int ret = 0; s = devm_kzalloc(&pdev->dev, sizeof(*s), GFP_KERNEL); if (!s) return -ENOMEM; s->muxc = devm_mux_control_get(dev, NULL); if (IS_ERR(s->muxc)) return dev_err_probe(&pdev->dev, PTR_ERR(s->muxc), "Failed to get mux\n"); platform_set_drvdata(pdev, s); ret = mdio_mux_init(&pdev->dev, pdev->dev.of_node, mdio_mux_multiplexer_switch_fn, &s->mux_handle, pdev, NULL); return ret; } static int mdio_mux_multiplexer_remove(struct platform_device *pdev) { struct mdio_mux_multiplexer_state *s = platform_get_drvdata(pdev); mdio_mux_uninit(s->mux_handle); if (s->do_deselect) mux_control_deselect(s->muxc); return 0; } static const struct of_device_id mdio_mux_multiplexer_match[] = { { .compatible = "mdio-mux-multiplexer", }, {}, }; MODULE_DEVICE_TABLE(of, mdio_mux_multiplexer_match); static struct platform_driver mdio_mux_multiplexer_driver = { .driver = { .name = "mdio-mux-multiplexer", .of_match_table = mdio_mux_multiplexer_match, }, .probe = mdio_mux_multiplexer_probe, .remove = mdio_mux_multiplexer_remove, }; module_platform_driver(mdio_mux_multiplexer_driver); MODULE_DESCRIPTION("MDIO bus multiplexer using kernel multiplexer subsystem"); MODULE_AUTHOR("Pankaj Bansal <pankaj.bansal@nxp.com>"); MODULE_LICENSE("GPL"); |