diff options
Diffstat (limited to 'drivers/net/phy/mdio-mux-mmioreg.c')
| -rw-r--r-- | drivers/net/phy/mdio-mux-mmioreg.c | 171 |
1 files changed, 171 insertions, 0 deletions
diff --git a/drivers/net/phy/mdio-mux-mmioreg.c b/drivers/net/phy/mdio-mux-mmioreg.c new file mode 100644 index 000000000000..9061ba622ac4 --- /dev/null +++ b/drivers/net/phy/mdio-mux-mmioreg.c @@ -0,0 +1,171 @@ +/* + * Simple memory-mapped device MDIO MUX driver + * + * Author: Timur Tabi <timur@freescale.com> + * + * Copyright 2012 Freescale Semiconductor, Inc. + * + * This file is licensed under the terms of the GNU General Public License + * version 2. This program is licensed "as is" without any warranty of any + * kind, whether express or implied. + */ + +#include <linux/platform_device.h> +#include <linux/device.h> +#include <linux/of_address.h> +#include <linux/of_mdio.h> +#include <linux/module.h> +#include <linux/init.h> +#include <linux/phy.h> +#include <linux/mdio-mux.h> + +struct mdio_mux_mmioreg_state { + void *mux_handle; + phys_addr_t phys; + uint8_t mask; +}; + +/* + * MDIO multiplexing switch function + * + * This function is called by the mdio-mux layer when it thinks the mdio bus + * multiplexer needs to switch. + * + * 'current_child' is the current value of the mux register (masked via + * s->mask). + * + * 'desired_child' is the value of the 'reg' property of the target child MDIO + * node. + * + * 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_mmioreg_switch_fn(int current_child, int desired_child, + void *data) +{ + struct mdio_mux_mmioreg_state *s = data; + + if (current_child ^ desired_child) { + void *p = ioremap(s->phys, 1); + uint8_t x, y; + + if (!p) + return -ENOMEM; + + x = ioread8(p); + y = (x & ~s->mask) | desired_child; + if (x != y) { + iowrite8((x & ~s->mask) | desired_child, p); + pr_debug("%s: %02x -> %02x\n", __func__, x, y); + } + + iounmap(p); + } + + return 0; +} + +static int __devinit mdio_mux_mmioreg_probe(struct platform_device *pdev) +{ + struct device_node *np2, *np = pdev->dev.of_node; + struct mdio_mux_mmioreg_state *s; + struct resource res; + const __be32 *iprop; + int len, ret; + + dev_dbg(&pdev->dev, "probing node %s\n", np->full_name); + + s = devm_kzalloc(&pdev->dev, sizeof(*s), GFP_KERNEL); + if (!s) + return -ENOMEM; + + ret = of_address_to_resource(np, 0, &res); + if (ret) { + dev_err(&pdev->dev, "could not obtain memory map for node %s\n", + np->full_name); + return ret; + } + s->phys = res.start; + + if (resource_size(&res) != sizeof(uint8_t)) { + dev_err(&pdev->dev, "only 8-bit registers are supported\n"); + return -EINVAL; + } + + iprop = of_get_property(np, "mux-mask", &len); + if (!iprop || len != sizeof(uint32_t)) { + dev_err(&pdev->dev, "missing or invalid mux-mask property\n"); + return -ENODEV; + } + if (be32_to_cpup(iprop) > 255) { + dev_err(&pdev->dev, "only 8-bit registers are supported\n"); + return -EINVAL; + } + s->mask = be32_to_cpup(iprop); + + /* + * Verify that the 'reg' property of each child MDIO bus does not + * set any bits outside of the 'mask'. + */ + for_each_available_child_of_node(np, np2) { + iprop = of_get_property(np2, "reg", &len); + if (!iprop || len != sizeof(uint32_t)) { + dev_err(&pdev->dev, "mdio-mux child node %s is " + "missing a 'reg' property\n", np2->full_name); + return -ENODEV; + } + if (be32_to_cpup(iprop) & ~s->mask) { + dev_err(&pdev->dev, "mdio-mux child node %s has " + "a 'reg' value with unmasked bits\n", + np2->full_name); + return -ENODEV; + } + } + + ret = mdio_mux_init(&pdev->dev, mdio_mux_mmioreg_switch_fn, + &s->mux_handle, s); + if (ret) { + dev_err(&pdev->dev, "failed to register mdio-mux bus %s\n", + np->full_name); + return ret; + } + + pdev->dev.platform_data = s; + + return 0; +} + +static int __devexit mdio_mux_mmioreg_remove(struct platform_device *pdev) +{ + struct mdio_mux_mmioreg_state *s = dev_get_platdata(&pdev->dev); + + mdio_mux_uninit(s->mux_handle); + + return 0; +} + +static struct of_device_id mdio_mux_mmioreg_match[] = { + { + .compatible = "mdio-mux-mmioreg", + }, + {}, +}; +MODULE_DEVICE_TABLE(of, mdio_mux_mmioreg_match); + +static struct platform_driver mdio_mux_mmioreg_driver = { + .driver = { + .name = "mdio-mux-mmioreg", + .owner = THIS_MODULE, + .of_match_table = mdio_mux_mmioreg_match, + }, + .probe = mdio_mux_mmioreg_probe, + .remove = __devexit_p(mdio_mux_mmioreg_remove), +}; + +module_platform_driver(mdio_mux_mmioreg_driver); + +MODULE_AUTHOR("Timur Tabi <timur@freescale.com>"); +MODULE_DESCRIPTION("Memory-mapped device MDIO MUX driver"); +MODULE_LICENSE("GPL v2"); |