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");