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

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2011, 2012 Cavium, Inc.
   4  */
   5
   6 #include <linux/device.h>
   7 #include <linux/gpio/consumer.h>
   8 #include <linux/mdio-mux.h>
   9 #include <linux/module.h>
  10 #include <linux/of_mdio.h>
  11 #include <linux/phy.h>
  12 #include <linux/platform_device.h>
  13
  14 #define DRV_VERSION "1.1"
  15 #define DRV_DESCRIPTION "GPIO controlled MDIO bus multiplexer driver"
  16
  17 struct mdio_mux_gpio_state {
  18         struct gpio_descs *gpios;
  19         void *mux_handle;
  20 };
  21
  22 static int mdio_mux_gpio_switch_fn(int current_child, int desired_child,
  23                                    void *data)
  24 {
  25         struct mdio_mux_gpio_state *s = data;
  26         DECLARE_BITMAP(values, BITS_PER_TYPE(desired_child));
  27
  28         if (current_child == desired_child)
  29                 return 0;
  30
  31         values[0] = desired_child;
  32
  33         gpiod_set_array_value_cansleep(s->gpios->ndescs, s->gpios->desc,
  34                                        s->gpios->info, values);
  35
  36         return 0;
  37 }
  38
  39 static int mdio_mux_gpio_probe(struct platform_device *pdev)
  40 {
  41         struct mdio_mux_gpio_state *s;
  42         struct gpio_descs *gpios;
  43         int r;
  44
  45         gpios = devm_gpiod_get_array(&pdev->dev, NULL, GPIOD_OUT_LOW);
  46         if (IS_ERR(gpios))
  47                 return PTR_ERR(gpios);
  48
  49         s = devm_kzalloc(&pdev->dev, sizeof(*s), GFP_KERNEL);
  50         if (!s)
  51                 return -ENOMEM;
  52
  53         s->gpios = gpios;
  54
  55         r = mdio_mux_init(&pdev->dev, pdev->dev.of_node,
  56                           mdio_mux_gpio_switch_fn, &s->mux_handle, s, NULL);
  57
  58         if (r != 0)
  59                 return r;
  60
  61         pdev->dev.platform_data = s;
  62         return 0;
  63 }
  64
  65 static void mdio_mux_gpio_remove(struct platform_device *pdev)
  66 {
  67         struct mdio_mux_gpio_state *s = dev_get_platdata(&pdev->dev);
  68         mdio_mux_uninit(s->mux_handle);
  69 }
  70
  71 static const struct of_device_id mdio_mux_gpio_match[] = {
  72         {
  73                 .compatible = "mdio-mux-gpio",
  74         },
  75         {
  76                 /* Legacy compatible property. */
  77                 .compatible = "cavium,mdio-mux-sn74cbtlv3253",
  78         },
  79         {},
  80 };
  81 MODULE_DEVICE_TABLE(of, mdio_mux_gpio_match);
  82
  83 static struct platform_driver mdio_mux_gpio_driver = {
  84         .driver = {
  85                 .name           = "mdio-mux-gpio",
  86                 .of_match_table = mdio_mux_gpio_match,
  87         },
  88         .probe          = mdio_mux_gpio_probe,
  89         .remove         = mdio_mux_gpio_remove,
  90 };
  91
  92 module_platform_driver(mdio_mux_gpio_driver);
  93
  94 MODULE_DESCRIPTION(DRV_DESCRIPTION);
  95 MODULE_VERSION(DRV_VERSION);
  96 MODULE_AUTHOR("David Daney");
  97 MODULE_LICENSE("GPL v2");