drivers/extcon/extcon-max3355.c

   1 /*
   2  * Maxim Integrated MAX3355 USB OTG chip extcon driver
   3  *
   4  * Copyright (C)  2014-2015 Cogent Embedded, Inc.
   5  * Author: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
   6  *
   7  * This software is licensed under the terms of the GNU General Public
   8  * License version 2, as published by the Free Software Foundation, and
   9  * may be copied, distributed, and modified under those terms.
  10  */
  11
  12 #include <linux/extcon-provider.h>
  13 #include <linux/gpio.h>
  14 #include <linux/gpio/consumer.h>
  15 #include <linux/interrupt.h>
  16 #include <linux/module.h>
  17 #include <linux/platform_device.h>
  18
  19 struct max3355_data {
  20         struct extcon_dev *edev;
  21         struct gpio_desc *id_gpiod;
  22         struct gpio_desc *shdn_gpiod;
  23 };
  24
  25 static const unsigned int max3355_cable[] = {
  26         EXTCON_USB,
  27         EXTCON_USB_HOST,
  28         EXTCON_NONE,
  29 };
  30
  31 static irqreturn_t max3355_id_irq(int irq, void *dev_id)
  32 {
  33         struct max3355_data *data = dev_id;
  34         int id = gpiod_get_value_cansleep(data->id_gpiod);
  35
  36         if (id) {
  37                 /*
  38                  * ID = 1 means USB HOST cable detached.
  39                  * As we don't have event for USB peripheral cable attached,
  40                  * we simulate USB peripheral attach here.
  41                  */
  42                 extcon_set_state_sync(data->edev, EXTCON_USB_HOST, false);
  43                 extcon_set_state_sync(data->edev, EXTCON_USB, true);
  44         } else {
  45                 /*
  46                  * ID = 0 means USB HOST cable attached.
  47                  * As we don't have event for USB peripheral cable detached,
  48                  * we simulate USB peripheral detach here.
  49                  */
  50                 extcon_set_state_sync(data->edev, EXTCON_USB, false);
  51                 extcon_set_state_sync(data->edev, EXTCON_USB_HOST, true);
  52         }
  53
  54         return IRQ_HANDLED;
  55 }
  56
  57 static int max3355_probe(struct platform_device *pdev)
  58 {
  59         struct max3355_data *data;
  60         struct gpio_desc *gpiod;
  61         int irq, err;
  62
  63         data = devm_kzalloc(&pdev->dev, sizeof(struct max3355_data),
  64                             GFP_KERNEL);
  65         if (!data)
  66                 return -ENOMEM;
  67
  68         gpiod = devm_gpiod_get(&pdev->dev, "id", GPIOD_IN);
  69         if (IS_ERR(gpiod)) {
  70                 dev_err(&pdev->dev, "failed to get ID_OUT GPIO\n");
  71                 return PTR_ERR(gpiod);
  72         }
  73         data->id_gpiod = gpiod;
  74
  75         gpiod = devm_gpiod_get(&pdev->dev, "maxim,shdn", GPIOD_OUT_HIGH);
  76         if (IS_ERR(gpiod)) {
  77                 dev_err(&pdev->dev, "failed to get SHDN# GPIO\n");
  78                 return PTR_ERR(gpiod);
  79         }
  80         data->shdn_gpiod = gpiod;
  81
  82         data->edev = devm_extcon_dev_allocate(&pdev->dev, max3355_cable);
  83         if (IS_ERR(data->edev)) {
  84                 dev_err(&pdev->dev, "failed to allocate extcon device\n");
  85                 return PTR_ERR(data->edev);
  86         }
  87
  88         err = devm_extcon_dev_register(&pdev->dev, data->edev);
  89         if (err < 0) {
  90                 dev_err(&pdev->dev, "failed to register extcon device\n");
  91                 return err;
  92         }
  93
  94         irq = gpiod_to_irq(data->id_gpiod);
  95         if (irq < 0) {
  96                 dev_err(&pdev->dev, "failed to translate ID_OUT GPIO to IRQ\n");
  97                 return irq;
  98         }
  99
 100         err = devm_request_threaded_irq(&pdev->dev, irq, NULL, max3355_id_irq,
 101                                         IRQF_ONESHOT | IRQF_NO_SUSPEND |
 102                                         IRQF_TRIGGER_RISING |
 103                                         IRQF_TRIGGER_FALLING,
 104                                         pdev->name, data);
 105         if (err < 0) {
 106                 dev_err(&pdev->dev, "failed to request ID_OUT IRQ\n");
 107                 return err;
 108         }
 109
 110         platform_set_drvdata(pdev, data);
 111
 112         /* Perform initial detection */
 113         max3355_id_irq(irq, data);
 114
 115         return 0;
 116 }
 117
 118 static int max3355_remove(struct platform_device *pdev)
 119 {
 120         struct max3355_data *data = platform_get_drvdata(pdev);
 121
 122         gpiod_set_value_cansleep(data->shdn_gpiod, 0);
 123
 124         return 0;
 125 }
 126
 127 static const struct of_device_id max3355_match_table[] = {
 128         { .compatible = "maxim,max3355", },
 129         { }
 130 };
 131 MODULE_DEVICE_TABLE(of, max3355_match_table);
 132
 133 static struct platform_driver max3355_driver = {
 134         .probe          = max3355_probe,
 135         .remove         = max3355_remove,
 136         .driver         = {
 137                 .name   = "extcon-max3355",
 138                 .of_match_table = max3355_match_table,
 139         },
 140 };
 141
 142 module_platform_driver(max3355_driver);
 143
 144 MODULE_AUTHOR("Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>");
 145 MODULE_DESCRIPTION("Maxim MAX3355 extcon driver");
 146 MODULE_LICENSE("GPL v2");