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.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
 19struct max3355_data {
 20	struct extcon_dev *edev;
 21	struct gpio_desc *id_gpiod;
 22	struct gpio_desc *shdn_gpiod;
 23};
 24
 25static const unsigned int max3355_cable[] = {
 26	EXTCON_USB,
 27	EXTCON_USB_HOST,
 28	EXTCON_NONE,
 29};
 30
 31static 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_cable_state_(data->edev, EXTCON_USB_HOST, false);
 43		extcon_set_cable_state_(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_cable_state_(data->edev, EXTCON_USB, false);
 51		extcon_set_cable_state_(data->edev, EXTCON_USB_HOST, true);
 52	}
 53
 54	return IRQ_HANDLED;
 55}
 56
 57static 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
118static 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
127static const struct of_device_id max3355_match_table[] = {
128	{ .compatible = "maxim,max3355", },
129	{ }
130};
131MODULE_DEVICE_TABLE(of, max3355_match_table);
132
133static 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
142module_platform_driver(max3355_driver);
143
144MODULE_AUTHOR("Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>");
145MODULE_DESCRIPTION("Maxim MAX3355 extcon driver");
146MODULE_LICENSE("GPL v2");