208 строки
4.8 KiB
C
208 строки
4.8 KiB
C
/*
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* Simple memory-mapped device MDIO MUX driver
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*
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* Author: Timur Tabi <timur@freescale.com>
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*
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* Copyright 2012 Freescale Semiconductor, Inc.
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*
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* This file is licensed under the terms of the GNU General Public License
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* version 2. This program is licensed "as is" without any warranty of any
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* kind, whether express or implied.
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*/
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#include <linux/platform_device.h>
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#include <linux/device.h>
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#include <linux/of_address.h>
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#include <linux/of_mdio.h>
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#include <linux/module.h>
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#include <linux/phy.h>
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#include <linux/mdio-mux.h>
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struct mdio_mux_mmioreg_state {
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void *mux_handle;
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phys_addr_t phys;
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unsigned int iosize;
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unsigned int mask;
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};
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/*
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* MDIO multiplexing switch function
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*
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* This function is called by the mdio-mux layer when it thinks the mdio bus
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* multiplexer needs to switch.
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*
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* 'current_child' is the current value of the mux register (masked via
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* s->mask).
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*
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* 'desired_child' is the value of the 'reg' property of the target child MDIO
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* node.
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*
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* The first time this function is called, current_child == -1.
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*
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* If current_child == desired_child, then the mux is already set to the
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* correct bus.
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*/
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static int mdio_mux_mmioreg_switch_fn(int current_child, int desired_child,
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void *data)
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{
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struct mdio_mux_mmioreg_state *s = data;
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if (current_child ^ desired_child) {
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void __iomem *p = ioremap(s->phys, s->iosize);
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if (!p)
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return -ENOMEM;
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switch (s->iosize) {
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case sizeof(uint8_t): {
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uint8_t x, y;
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x = ioread8(p);
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y = (x & ~s->mask) | desired_child;
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if (x != y) {
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iowrite8((x & ~s->mask) | desired_child, p);
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pr_debug("%s: %02x -> %02x\n", __func__, x, y);
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}
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break;
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}
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case sizeof(uint16_t): {
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uint16_t x, y;
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x = ioread16(p);
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y = (x & ~s->mask) | desired_child;
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if (x != y) {
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iowrite16((x & ~s->mask) | desired_child, p);
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pr_debug("%s: %04x -> %04x\n", __func__, x, y);
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}
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break;
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}
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case sizeof(uint32_t): {
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uint32_t x, y;
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x = ioread32(p);
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y = (x & ~s->mask) | desired_child;
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if (x != y) {
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iowrite32((x & ~s->mask) | desired_child, p);
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pr_debug("%s: %08x -> %08x\n", __func__, x, y);
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}
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break;
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}
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}
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iounmap(p);
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}
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return 0;
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}
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static int mdio_mux_mmioreg_probe(struct platform_device *pdev)
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{
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struct device_node *np2, *np = pdev->dev.of_node;
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struct mdio_mux_mmioreg_state *s;
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struct resource res;
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const __be32 *iprop;
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int len, ret;
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dev_dbg(&pdev->dev, "probing node %pOF\n", np);
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s = devm_kzalloc(&pdev->dev, sizeof(*s), GFP_KERNEL);
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if (!s)
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return -ENOMEM;
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ret = of_address_to_resource(np, 0, &res);
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if (ret) {
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dev_err(&pdev->dev, "could not obtain memory map for node %pOF\n",
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np);
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return ret;
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}
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s->phys = res.start;
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s->iosize = resource_size(&res);
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if (s->iosize != sizeof(uint8_t) &&
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s->iosize != sizeof(uint16_t) &&
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s->iosize != sizeof(uint32_t)) {
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dev_err(&pdev->dev, "only 8/16/32-bit registers are supported\n");
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return -EINVAL;
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}
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iprop = of_get_property(np, "mux-mask", &len);
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if (!iprop || len != sizeof(uint32_t)) {
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dev_err(&pdev->dev, "missing or invalid mux-mask property\n");
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return -ENODEV;
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}
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if (be32_to_cpup(iprop) >= BIT(s->iosize * 8)) {
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dev_err(&pdev->dev, "only 8/16/32-bit registers are supported\n");
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return -EINVAL;
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}
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s->mask = be32_to_cpup(iprop);
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/*
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* Verify that the 'reg' property of each child MDIO bus does not
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* set any bits outside of the 'mask'.
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*/
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for_each_available_child_of_node(np, np2) {
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iprop = of_get_property(np2, "reg", &len);
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if (!iprop || len != sizeof(uint32_t)) {
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dev_err(&pdev->dev, "mdio-mux child node %pOF is "
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"missing a 'reg' property\n", np2);
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of_node_put(np2);
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return -ENODEV;
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}
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if (be32_to_cpup(iprop) & ~s->mask) {
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dev_err(&pdev->dev, "mdio-mux child node %pOF has "
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"a 'reg' value with unmasked bits\n",
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np2);
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of_node_put(np2);
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return -ENODEV;
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}
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}
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ret = mdio_mux_init(&pdev->dev, pdev->dev.of_node,
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mdio_mux_mmioreg_switch_fn,
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&s->mux_handle, s, NULL);
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if (ret) {
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if (ret != -EPROBE_DEFER)
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dev_err(&pdev->dev,
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"failed to register mdio-mux bus %pOF\n", np);
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return ret;
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}
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pdev->dev.platform_data = s;
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return 0;
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}
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static int mdio_mux_mmioreg_remove(struct platform_device *pdev)
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{
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struct mdio_mux_mmioreg_state *s = dev_get_platdata(&pdev->dev);
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mdio_mux_uninit(s->mux_handle);
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return 0;
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}
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static const struct of_device_id mdio_mux_mmioreg_match[] = {
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{
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.compatible = "mdio-mux-mmioreg",
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},
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{},
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};
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MODULE_DEVICE_TABLE(of, mdio_mux_mmioreg_match);
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static struct platform_driver mdio_mux_mmioreg_driver = {
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.driver = {
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.name = "mdio-mux-mmioreg",
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.of_match_table = mdio_mux_mmioreg_match,
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},
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.probe = mdio_mux_mmioreg_probe,
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.remove = mdio_mux_mmioreg_remove,
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};
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module_platform_driver(mdio_mux_mmioreg_driver);
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MODULE_AUTHOR("Timur Tabi <timur@freescale.com>");
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MODULE_DESCRIPTION("Memory-mapped device MDIO MUX driver");
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MODULE_LICENSE("GPL v2");
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