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416912a1 DD |
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 | ||
23 | struct mdio_mux_gpio_state { | |
24 | int gpio[MDIO_MUX_GPIO_MAX_BITS]; | |
25 | unsigned int num_gpios; | |
26 | void *mux_handle; | |
27 | }; | |
28 | ||
29 | static 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 | ||
633d1594 | 52 | static int mdio_mux_gpio_probe(struct platform_device *pdev) |
416912a1 DD |
53 | { |
54 | enum of_gpio_flags f; | |
55 | struct mdio_mux_gpio_state *s; | |
e80beb27 | 56 | int num_gpios; |
416912a1 DD |
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); | |
e80beb27 | 64 | if (num_gpios <= 0 || num_gpios > MDIO_MUX_GPIO_MAX_BITS) |
416912a1 DD |
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 | } | |
99 | err: | |
100 | while (n) { | |
101 | n--; | |
102 | gpio_free(s->gpio[n]); | |
103 | } | |
416912a1 DD |
104 | return r; |
105 | } | |
106 | ||
633d1594 | 107 | static int mdio_mux_gpio_remove(struct platform_device *pdev) |
416912a1 DD |
108 | { |
109 | struct mdio_mux_gpio_state *s = pdev->dev.platform_data; | |
110 | mdio_mux_uninit(s->mux_handle); | |
111 | return 0; | |
112 | } | |
113 | ||
114 | static 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 | }; | |
124 | MODULE_DEVICE_TABLE(of, mdio_mux_gpio_match); | |
125 | ||
126 | static 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, | |
633d1594 | 133 | .remove = mdio_mux_gpio_remove, |
416912a1 DD |
134 | }; |
135 | ||
136 | module_platform_driver(mdio_mux_gpio_driver); | |
137 | ||
138 | MODULE_DESCRIPTION(DRV_DESCRIPTION); | |
139 | MODULE_VERSION(DRV_VERSION); | |
140 | MODULE_AUTHOR("David Daney"); | |
141 | MODULE_LICENSE("GPL"); |