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204 lines
4.7 KiB
204 lines
4.7 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* Simple memory-mapped device MDIO MUX driver |
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* |
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* Author: Timur Tabi <[email protected]> |
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* |
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* Copyright 2012 Freescale Semiconductor, Inc. |
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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 <[email protected]>"); |
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MODULE_DESCRIPTION("Memory-mapped device MDIO MUX driver"); |
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MODULE_LICENSE("GPL v2");
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