LXR 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/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");
 142