forked from Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
122 lines
3.1 KiB
122 lines
3.1 KiB
// SPDX-License-Identifier: GPL-2.0+ |
|
/* MDIO bus multiplexer using kernel multiplexer subsystem |
|
* |
|
* Copyright 2019 NXP |
|
*/ |
|
|
|
#include <linux/platform_device.h> |
|
#include <linux/mdio-mux.h> |
|
#include <linux/module.h> |
|
#include <linux/mux/consumer.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)) { |
|
ret = PTR_ERR(s->muxc); |
|
if (ret != -EPROBE_DEFER) |
|
dev_err(&pdev->dev, "Failed to get mux: %d\n", ret); |
|
return ret; |
|
} |
|
|
|
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 <[email protected]>"); |
|
MODULE_LICENSE("GPL");
|
|
|