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 "1.1"
  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         struct gpio_desc *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 values[MDIO_MUX_GPIO_MAX_BITS];
  32         unsigned int n;
  33         struct mdio_mux_gpio_state *s = data;
  34
  35         if (current_child == desired_child)
  36                 return 0;
  37
  38         for (n = 0; n < s->num_gpios; n++) {
  39                 values[n] = (desired_child >> n) & 1;
  40         }
  41         gpiod_set_array_cansleep(s->num_gpios, s->gpio, values);
  42
  43         return 0;
  44 }
  45
  46 static int mdio_mux_gpio_probe(struct platform_device *pdev)
  47 {
  48         struct mdio_mux_gpio_state *s;
  49         int num_gpios;
  50         unsigned int n;
  51         int r;
  52
  53         if (!pdev->dev.of_node)
  54                 return -ENODEV;
  55
  56         num_gpios = of_gpio_count(pdev->dev.of_node);
  57         if (num_gpios <= 0 || num_gpios > MDIO_MUX_GPIO_MAX_BITS)
  58                 return -ENODEV;
  59
  60         s = devm_kzalloc(&pdev->dev, sizeof(*s), GFP_KERNEL);
  61         if (!s)
  62                 return -ENOMEM;
  63
  64         s->num_gpios = num_gpios;
  65
  66         for (n = 0; n < num_gpios; ) {
  67                 struct gpio_desc *gpio = gpiod_get_index(&pdev->dev, NULL, n,
  68                                                          GPIOD_OUT_LOW);
  69                 if (IS_ERR(gpio)) {
  70                         r = PTR_ERR(gpio);
  71                         goto err;
  72                 }
  73                 s->gpio[n] = gpio;
  74                 n++;
  75         }
  76
  77         r = mdio_mux_init(&pdev->dev,
  78                           mdio_mux_gpio_switch_fn, &s->mux_handle, s);
  79
  80         if (r == 0) {
  81                 pdev->dev.platform_data = s;
  82                 return 0;
  83         }
  84 err:
  85         while (n) {
  86                 n--;
  87                 gpiod_put(s->gpio[n]);
  88         }
  89         return r;
  90 }
  91
  92 static int mdio_mux_gpio_remove(struct platform_device *pdev)
  93 {
  94         unsigned int n;
  95         struct mdio_mux_gpio_state *s = dev_get_platdata(&pdev->dev);
  96         mdio_mux_uninit(s->mux_handle);
  97         for (n = 0; n < s->num_gpios; n++)
  98                 gpiod_put(s->gpio[n]);
  99         return 0;
 100 }
 101
 102 static struct of_device_id mdio_mux_gpio_match[] = {
 103         {
 104                 .compatible = "mdio-mux-gpio",
 105         },
 106         {
 107                 /* Legacy compatible property. */
 108                 .compatible = "cavium,mdio-mux-sn74cbtlv3253",
 109         },
 110         {},
 111 };
 112 MODULE_DEVICE_TABLE(of, mdio_mux_gpio_match);
 113
 114 static struct platform_driver mdio_mux_gpio_driver = {
 115         .driver = {
 116                 .name           = "mdio-mux-gpio",
 117                 .of_match_table = mdio_mux_gpio_match,
 118         },
 119         .probe          = mdio_mux_gpio_probe,
 120         .remove         = mdio_mux_gpio_remove,
 121 };
 122
 123 module_platform_driver(mdio_mux_gpio_driver);
 124
 125 MODULE_DESCRIPTION(DRV_DESCRIPTION);
 126 MODULE_VERSION(DRV_VERSION);
 127 MODULE_AUTHOR("David Daney");
 128 MODULE_LICENSE("GPL");