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