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/init.h>
14#include <linux/phy.h>
15#include <linux/mdio-mux.h>
16#include <linux/of_gpio.h>
17
18#define DRV_VERSION "1.0"
19#define DRV_DESCRIPTION "GPIO controlled MDIO bus multiplexer driver"
20
21#define MDIO_MUX_GPIO_MAX_BITS 8
22
23struct mdio_mux_gpio_state {
24 int gpio[MDIO_MUX_GPIO_MAX_BITS];
25 unsigned int num_gpios;
26 void *mux_handle;
27};
28
29static int mdio_mux_gpio_switch_fn(int current_child, int desired_child,
30 void *data)
31{
32 int change;
33 unsigned int n;
34 struct mdio_mux_gpio_state *s = data;
35
36 if (current_child == desired_child)
37 return 0;
38
39 change = current_child == -1 ? -1 : current_child ^ desired_child;
40
41 for (n = 0; n < s->num_gpios; n++) {
42 if (change & 1)
43 gpio_set_value_cansleep(s->gpio[n],
44 (desired_child & 1) != 0);
45 change >>= 1;
46 desired_child >>= 1;
47 }
48
49 return 0;
50}
51
52static int mdio_mux_gpio_probe(struct platform_device *pdev)
53{
54 enum of_gpio_flags f;
55 struct mdio_mux_gpio_state *s;
56 int num_gpios;
57 unsigned int n;
58 int r;
59
60 if (!pdev->dev.of_node)
61 return -ENODEV;
62
63 num_gpios = of_gpio_count(pdev->dev.of_node);
64 if (num_gpios <= 0 || num_gpios > MDIO_MUX_GPIO_MAX_BITS)
65 return -ENODEV;
66
67 s = devm_kzalloc(&pdev->dev, sizeof(*s), GFP_KERNEL);
68 if (!s)
69 return -ENOMEM;
70
71 s->num_gpios = num_gpios;
72
73 for (n = 0; n < num_gpios; ) {
74 int gpio = of_get_gpio_flags(pdev->dev.of_node, n, &f);
75 if (gpio < 0) {
76 r = (gpio == -ENODEV) ? -EPROBE_DEFER : gpio;
77 goto err;
78 }
79 s->gpio[n] = gpio;
80
81 n++;
82
83 r = gpio_request(gpio, "mdio_mux_gpio");
84 if (r)
85 goto err;
86
87 r = gpio_direction_output(gpio, 0);
88 if (r)
89 goto err;
90 }
91
92 r = mdio_mux_init(&pdev->dev,
93 mdio_mux_gpio_switch_fn, &s->mux_handle, s);
94
95 if (r == 0) {
96 pdev->dev.platform_data = s;
97 return 0;
98 }
99err:
100 while (n) {
101 n--;
102 gpio_free(s->gpio[n]);
103 }
104 return r;
105}
106
107static int mdio_mux_gpio_remove(struct platform_device *pdev)
108{
109 struct mdio_mux_gpio_state *s = pdev->dev.platform_data;
110 mdio_mux_uninit(s->mux_handle);
111 return 0;
112}
113
114static struct of_device_id mdio_mux_gpio_match[] = {
115 {
116 .compatible = "mdio-mux-gpio",
117 },
118 {
119 /* Legacy compatible property. */
120 .compatible = "cavium,mdio-mux-sn74cbtlv3253",
121 },
122 {},
123};
124MODULE_DEVICE_TABLE(of, mdio_mux_gpio_match);
125
126static struct platform_driver mdio_mux_gpio_driver = {
127 .driver = {
128 .name = "mdio-mux-gpio",
129 .owner = THIS_MODULE,
130 .of_match_table = mdio_mux_gpio_match,
131 },
132 .probe = mdio_mux_gpio_probe,
133 .remove = mdio_mux_gpio_remove,
134};
135
136module_platform_driver(mdio_mux_gpio_driver);
137
138MODULE_DESCRIPTION(DRV_DESCRIPTION);
139MODULE_VERSION(DRV_VERSION);
140MODULE_AUTHOR("David Daney");
141MODULE_LICENSE("GPL");