Version:  2.0.40 2.2.26 2.4.37 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17

Linux/drivers/net/phy/mdio-mux-gpio.c

  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 
 22 struct mdio_mux_gpio_state {
 23         int gpio[MDIO_MUX_GPIO_MAX_BITS];
 24         unsigned int num_gpios;
 25         void *mux_handle;
 26 };
 27 
 28 static 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 
 51 static 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         }
 98 err:
 99         while (n) {
100                 n--;
101                 gpio_free(s->gpio[n]);
102         }
103         return r;
104 }
105 
106 static 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 
113 static 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 };
123 MODULE_DEVICE_TABLE(of, mdio_mux_gpio_match);
124 
125 static 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 
135 module_platform_driver(mdio_mux_gpio_driver);
136 
137 MODULE_DESCRIPTION(DRV_DESCRIPTION);
138 MODULE_VERSION(DRV_VERSION);
139 MODULE_AUTHOR("David Daney");
140 MODULE_LICENSE("GPL");
141 

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