1 // SPDX-License-Identifier: GPL-2.0
3 * Simple memory-mapped device MDIO MUX driver
5 * Author: Timur Tabi <timur@freescale.com>
7 * Copyright 2012 Freescale Semiconductor, Inc.
10 #include <linux/device.h>
11 #include <linux/mdio-mux.h>
12 #include <linux/module.h>
13 #include <linux/of_address.h>
14 #include <linux/of_mdio.h>
15 #include <linux/phy.h>
16 #include <linux/platform_device.h>
18 struct mdio_mux_mmioreg_state {
26 * MDIO multiplexing switch function
28 * This function is called by the mdio-mux layer when it thinks the mdio bus
29 * multiplexer needs to switch.
31 * 'current_child' is the current value of the mux register (masked via
34 * 'desired_child' is the value of the 'reg' property of the target child MDIO
37 * The first time this function is called, current_child == -1.
39 * If current_child == desired_child, then the mux is already set to the
42 static int mdio_mux_mmioreg_switch_fn(int current_child, int desired_child,
45 struct mdio_mux_mmioreg_state *s = data;
47 if (current_child ^ desired_child) {
48 void __iomem *p = ioremap(s->phys, s->iosize);
53 case sizeof(uint8_t): {
57 y = (x & ~s->mask) | desired_child;
59 iowrite8((x & ~s->mask) | desired_child, p);
60 pr_debug("%s: %02x -> %02x\n", __func__, x, y);
65 case sizeof(uint16_t): {
69 y = (x & ~s->mask) | desired_child;
71 iowrite16((x & ~s->mask) | desired_child, p);
72 pr_debug("%s: %04x -> %04x\n", __func__, x, y);
77 case sizeof(uint32_t): {
81 y = (x & ~s->mask) | desired_child;
83 iowrite32((x & ~s->mask) | desired_child, p);
84 pr_debug("%s: %08x -> %08x\n", __func__, x, y);
97 static int mdio_mux_mmioreg_probe(struct platform_device *pdev)
99 struct device_node *np2, *np = pdev->dev.of_node;
100 struct mdio_mux_mmioreg_state *s;
105 dev_dbg(&pdev->dev, "probing node %pOF\n", np);
107 s = devm_kzalloc(&pdev->dev, sizeof(*s), GFP_KERNEL);
111 ret = of_address_to_resource(np, 0, &res);
113 dev_err(&pdev->dev, "could not obtain memory map for node %pOF\n",
119 s->iosize = resource_size(&res);
120 if (s->iosize != sizeof(uint8_t) &&
121 s->iosize != sizeof(uint16_t) &&
122 s->iosize != sizeof(uint32_t)) {
123 dev_err(&pdev->dev, "only 8/16/32-bit registers are supported\n");
127 iprop = of_get_property(np, "mux-mask", &len);
128 if (!iprop || len != sizeof(uint32_t)) {
129 dev_err(&pdev->dev, "missing or invalid mux-mask property\n");
132 if (be32_to_cpup(iprop) >= BIT(s->iosize * 8)) {
133 dev_err(&pdev->dev, "only 8/16/32-bit registers are supported\n");
136 s->mask = be32_to_cpup(iprop);
139 * Verify that the 'reg' property of each child MDIO bus does not
140 * set any bits outside of the 'mask'.
142 for_each_available_child_of_node(np, np2) {
143 iprop = of_get_property(np2, "reg", &len);
144 if (!iprop || len != sizeof(uint32_t)) {
145 dev_err(&pdev->dev, "mdio-mux child node %pOF is "
146 "missing a 'reg' property\n", np2);
150 if (be32_to_cpup(iprop) & ~s->mask) {
151 dev_err(&pdev->dev, "mdio-mux child node %pOF has "
152 "a 'reg' value with unmasked bits\n",
159 ret = mdio_mux_init(&pdev->dev, pdev->dev.of_node,
160 mdio_mux_mmioreg_switch_fn,
161 &s->mux_handle, s, NULL);
163 return dev_err_probe(&pdev->dev, ret,
164 "failed to register mdio-mux bus %pOF\n", np);
166 pdev->dev.platform_data = s;
171 static int mdio_mux_mmioreg_remove(struct platform_device *pdev)
173 struct mdio_mux_mmioreg_state *s = dev_get_platdata(&pdev->dev);
175 mdio_mux_uninit(s->mux_handle);
180 static const struct of_device_id mdio_mux_mmioreg_match[] = {
182 .compatible = "mdio-mux-mmioreg",
186 MODULE_DEVICE_TABLE(of, mdio_mux_mmioreg_match);
188 static struct platform_driver mdio_mux_mmioreg_driver = {
190 .name = "mdio-mux-mmioreg",
191 .of_match_table = mdio_mux_mmioreg_match,
193 .probe = mdio_mux_mmioreg_probe,
194 .remove = mdio_mux_mmioreg_remove,
197 module_platform_driver(mdio_mux_mmioreg_driver);
199 MODULE_AUTHOR("Timur Tabi <timur@freescale.com>");
200 MODULE_DESCRIPTION("Memory-mapped device MDIO MUX driver");
201 MODULE_LICENSE("GPL v2");