tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * This file is subject to the terms and conditions of the GNU General Public
3 * License. See the file "COPYING" in the main directory of this archive
4 * for more details.
5 *
6 * Copyright (C) 2011, 2012 Cavium, Inc.
7 */
8
9#include <linux/platform_device.h>
10#include <linux/device.h>
11#include <linux/of_mdio.h>
12#include <linux/module.h>
13#include <linux/phy.h>
14#include <linux/mdio-mux.h>
15#include <linux/of_gpio.h>
16
17#define DRV_VERSION "1.0"
18#define DRV_DESCRIPTION "GPIO controlled MDIO bus multiplexer driver"
19
20#define MDIO_MUX_GPIO_MAX_BITS 8
21
22struct mdio_mux_gpio_state {
23 int gpio[MDIO_MUX_GPIO_MAX_BITS];
24 unsigned int num_gpios;
25 void *mux_handle;
26};
27
28static int mdio_mux_gpio_switch_fn(int current_child, int desired_child,
29 void *data)
30{
31 int change;
32 unsigned int n;
33 struct mdio_mux_gpio_state *s = data;
34
35 if (current_child == desired_child)
36 return 0;
37
38 change = current_child == -1 ? -1 : current_child ^ desired_child;
39
40 for (n = 0; n < s->num_gpios; n++) {
41 if (change & 1)
42 gpio_set_value_cansleep(s->gpio[n],
43 (desired_child & 1) != 0);
44 change >>= 1;
45 desired_child >>= 1;
46 }
47
48 return 0;
49}
50
51static int mdio_mux_gpio_probe(struct platform_device *pdev)
52{
53 enum of_gpio_flags f;
54 struct mdio_mux_gpio_state *s;
55 int num_gpios;
56 unsigned int n;
57 int r;
58
59 if (!pdev->dev.of_node)
60 return -ENODEV;
61
62 num_gpios = of_gpio_count(pdev->dev.of_node);
63 if (num_gpios <= 0 || num_gpios > MDIO_MUX_GPIO_MAX_BITS)
64 return -ENODEV;
65
66 s = devm_kzalloc(&pdev->dev, sizeof(*s), GFP_KERNEL);
67 if (!s)
68 return -ENOMEM;
69
70 s->num_gpios = num_gpios;
71
72 for (n = 0; n < num_gpios; ) {
73 int gpio = of_get_gpio_flags(pdev->dev.of_node, n, &f);
74 if (gpio < 0) {
75 r = (gpio == -ENODEV) ? -EPROBE_DEFER : gpio;
76 goto err;
77 }
78 s->gpio[n] = gpio;
79
80 n++;
81
82 r = gpio_request(gpio, "mdio_mux_gpio");
83 if (r)
84 goto err;
85
86 r = gpio_direction_output(gpio, 0);
87 if (r)
88 goto err;
89 }
90
91 r = mdio_mux_init(&pdev->dev,
92 mdio_mux_gpio_switch_fn, &s->mux_handle, s);
93
94 if (r == 0) {
95 pdev->dev.platform_data = s;
96 return 0;
97 }
98err:
99 while (n) {
100 n--;
101 gpio_free(s->gpio[n]);
102 }
103 return r;
104}
105
106static int mdio_mux_gpio_remove(struct platform_device *pdev)
107{
108 struct mdio_mux_gpio_state *s = dev_get_platdata(&pdev->dev);
109 mdio_mux_uninit(s->mux_handle);
110 return 0;
111}
112
113static struct of_device_id mdio_mux_gpio_match[] = {
114 {
115 .compatible = "mdio-mux-gpio",
116 },
117 {
118 /* Legacy compatible property. */
119 .compatible = "cavium,mdio-mux-sn74cbtlv3253",
120 },
121 {},
122};
123MODULE_DEVICE_TABLE(of, mdio_mux_gpio_match);
124
125static struct platform_driver mdio_mux_gpio_driver = {
126 .driver = {
127 .name = "mdio-mux-gpio",
128 .owner = THIS_MODULE,
129 .of_match_table = mdio_mux_gpio_match,
130 },
131 .probe = mdio_mux_gpio_probe,
132 .remove = mdio_mux_gpio_remove,
133};
134
135module_platform_driver(mdio_mux_gpio_driver);
136
137MODULE_DESCRIPTION(DRV_DESCRIPTION);
138MODULE_VERSION(DRV_VERSION);
139MODULE_AUTHOR("David Daney");
140MODULE_LICENSE("GPL");