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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 "1.1"
 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");
129 

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