drivers/misc/micro_usb_switch.c

   1 /*
   2  *  Copyright (C) 2009 Samsung Electronics
   3  *  Minkyu Kang <mk7.kang@samsung.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  18  *
  19  */
  20
  21 #include <linux/kernel.h>
  22 #include <linux/module.h>
  23 #include <linux/init.h>
  24 #include <linux/slab.h>
  25 #include <linux/platform_device.h>
  26 #include <linux/micro_usb_switch.h>
  27
  28 struct micro_usb_switch {
  29         struct micro_usb_switch_platform_data   *pdata;
  30         int                                     path;
  31 };
  32
  33 static ssize_t micro_usb_switch_show_state(struct device *dev,
  34                 struct device_attribute *attr, char *buf)
  35 {
  36         struct micro_usb_switch *usb_switch=
  37                         platform_get_drvdata(to_platform_device(dev));
  38         struct micro_usb_switch_platform_data *pdata = usb_switch->pdata;
  39         int ret;
  40         int path;
  41
  42         path = pdata->get_usb_switch();
  43
  44         if (path == USB_PATH_AP)
  45                 ret = sprintf(buf, "AP\n");
  46         else if (path == USB_PATH_CP)
  47                 ret = sprintf(buf, "CP\n");
  48         else
  49                 ret = sprintf(buf, "NA\n");
  50
  51         return ret;
  52 }
  53
  54 static ssize_t micro_usb_switch_store_state(struct device *dev,
  55                 struct device_attribute *attr, const char *buf, size_t count)
  56 {
  57         struct micro_usb_switch *usb_switch=
  58                         platform_get_drvdata(to_platform_device(dev));
  59         struct micro_usb_switch_platform_data *pdata = usb_switch->pdata;
  60         int path;
  61
  62         if (!count)
  63                 return -EINVAL;
  64
  65         if (!strncmp(buf, "CP", 2))
  66                 path = USB_PATH_CP;
  67         else if (!strncmp(buf, "AP", 2))
  68                 path = USB_PATH_AP;
  69         else
  70                 return count;
  71
  72         if (path == usb_switch->path)
  73                 return count;
  74
  75         pdata->set_usb_switch(path);
  76
  77         if (pdata->usb_power) {
  78                 pdata->usb_power(path, USB_PATH_CP);
  79                 pdata->usb_power(!path, USB_PATH_AP);
  80         }
  81
  82         usb_switch->path = path;
  83
  84         return count;
  85 }
  86
  87 static struct device_attribute micro_usb_switch_attr = {
  88         .attr = {
  89                 .name = "path",
  90                 .mode = 0644,
  91         },
  92         .show = micro_usb_switch_show_state,
  93         .store = micro_usb_switch_store_state,
  94 };
  95
  96 static int __devinit usb_switch_probe(struct platform_device *pdev)
  97 {
  98         struct micro_usb_switch_platform_data *pdata = pdev->dev.platform_data;
  99         struct micro_usb_switch *usb_switch;
 100         int ret;
 101
 102         usb_switch = kzalloc(sizeof(struct micro_usb_switch), GFP_KERNEL);
 103         if (!usb_switch) {
 104                 dev_err(&pdev->dev, "failed to allocate driver data\n");
 105                 return -ENOMEM;
 106         }
 107
 108         platform_set_drvdata(pdev, usb_switch);
 109         usb_switch->pdata = pdata;
 110         usb_switch->path = pdata->default_path;
 111
 112         ret = device_create_file(&pdev->dev, &micro_usb_switch_attr);
 113         if (ret) {
 114                 dev_err(&pdev->dev, "failed to crreate device file\n");
 115                 return ret;
 116         }
 117
 118         return 0;
 119 }
 120
 121 static int __devexit usb_switch_remove(struct platform_device *pdev)
 122 {
 123         platform_set_drvdata(pdev, NULL);
 124         return 0;
 125 }
 126
 127 static struct platform_driver usb_switch_driver = {
 128         .probe          = usb_switch_probe,
 129         .remove         = __devexit_p(usb_switch_remove),
 130         .driver         = {
 131                 .name   = "usb-switch",
 132                 .owner  = THIS_MODULE,
 133         },
 134 };
 135
 136 static int __init usb_switch_init(void)
 137 {
 138         return platform_driver_register(&usb_switch_driver);
 139 }
 140 module_init(usb_switch_init);
 141
 142 static void __exit usb_switch_exit(void)
 143 {
 144         platform_driver_unregister(&usb_switch_driver);
 145 }
 146 module_exit(usb_switch_exit);
 147
 148 MODULE_AUTHOR("Minkyu Kang <mk7.kang@samsung.com>");
 149 MODULE_DESCRIPTION("Micro USB Switch Driver");
 150 MODULE_LICENSE("GPL");