summaryrefslogtreecommitdiffstats
path: root/drivers/net/phy/mdio-mux-gpio.c
blob: 320eb15315c85bc16e8372704f1656e7a91c6404 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (C) 2011, 2012 Cavium, Inc.
 */

#include <linux/platform_device.h>
#include <linux/device.h>
#include <linux/of_mdio.h>
#include <linux/module.h>
#include <linux/phy.h>
#include <linux/mdio-mux.h>
#include <linux/of_gpio.h>

#define DRV_VERSION "1.1"
#define DRV_DESCRIPTION "GPIO controlled MDIO bus multiplexer driver"

#define MDIO_MUX_GPIO_MAX_BITS 8

struct mdio_mux_gpio_state {
	struct gpio_desc *gpio[MDIO_MUX_GPIO_MAX_BITS];
	unsigned int num_gpios;
	void *mux_handle;
};

static int mdio_mux_gpio_switch_fn(int current_child, int desired_child,
				   void *data)
{
	int values[MDIO_MUX_GPIO_MAX_BITS];
	unsigned int n;
	struct mdio_mux_gpio_state *s = data;

	if (current_child == desired_child)
		return 0;

	for (n = 0; n < s->num_gpios; n++) {
		values[n] = (desired_child >> n) & 1;
	}
	gpiod_set_array_cansleep(s->num_gpios, s->gpio, values);

	return 0;
}

static int mdio_mux_gpio_probe(struct platform_device *pdev)
{
	struct mdio_mux_gpio_state *s;
	int num_gpios;
	unsigned int n;
	int r;

	if (!pdev->dev.of_node)
		return -ENODEV;

	num_gpios = of_gpio_count(pdev->dev.of_node);
	if (num_gpios <= 0 || num_gpios > MDIO_MUX_GPIO_MAX_BITS)
		return -ENODEV;

	s = devm_kzalloc(&pdev->dev, sizeof(*s), GFP_KERNEL);
	if (!s)
		return -ENOMEM;

	s->num_gpios = num_gpios;

	for (n = 0; n < num_gpios; ) {
		struct gpio_desc *gpio = gpiod_get_index(&pdev->dev, NULL, n,
							 GPIOD_OUT_LOW);
		if (IS_ERR(gpio)) {
			r = PTR_ERR(gpio);
			goto err;
		}
		s->gpio[n] = gpio;
		n++;
	}

	r = mdio_mux_init(&pdev->dev,
			  mdio_mux_gpio_switch_fn, &s->mux_handle, s);

	if (r == 0) {
		pdev->dev.platform_data = s;
		return 0;
	}
err:
	while (n) {
		n--;
		gpiod_put(s->gpio[n]);
	}
	return r;
}

static int mdio_mux_gpio_remove(struct platform_device *pdev)
{
	unsigned int n;
	struct mdio_mux_gpio_state *s = dev_get_platdata(&pdev->dev);
	mdio_mux_uninit(s->mux_handle);
	for (n = 0; n < s->num_gpios; n++)
		gpiod_put(s->gpio[n]);
	return 0;
}

static struct of_device_id mdio_mux_gpio_match[] = {
	{
		.compatible = "mdio-mux-gpio",
	},
	{
		/* Legacy compatible property. */
		.compatible = "cavium,mdio-mux-sn74cbtlv3253",
	},
	{},
};
MODULE_DEVICE_TABLE(of, mdio_mux_gpio_match);

static struct platform_driver mdio_mux_gpio_driver = {
	.driver = {
		.name		= "mdio-mux-gpio",
		.of_match_table = mdio_mux_gpio_match,
	},
	.probe		= mdio_mux_gpio_probe,
	.remove		= mdio_mux_gpio_remove,
};

module_platform_driver(mdio_mux_gpio_driver);

MODULE_DESCRIPTION(DRV_DESCRIPTION);
MODULE_VERSION(DRV_VERSION);
MODULE_AUTHOR("David Daney");
MODULE_LICENSE("GPL");