1 /*
2  * Intel INT3496 ACPI device extcon driver
3  *
4  * Copyright (c) 2016 Hans de Goede <hdegoede@redhat.com>
5  *
6  * Based on android x86 kernel code which is:
7  *
8  * Copyright (c) 2014, Intel Corporation.
9  * Author: David Cohen <david.a.cohen@linux.intel.com>
10  *
11  * This program is free software; you can redistribute it and/or modify
12  * it under the terms of the GNU General Public License version 2 as
13  * published by the Free Software Foundation.
14  *
15  * This program is distributed in the hope that it will be useful,
16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
18  * GNU General Public License for more details.
19  */
20 
21 #include <linux/acpi.h>
22 #include <linux/extcon-provider.h>
23 #include <linux/gpio.h>
24 #include <linux/interrupt.h>
25 #include <linux/module.h>
26 #include <linux/platform_device.h>
27 
28 #define INT3496_GPIO_USB_ID	0
29 #define INT3496_GPIO_VBUS_EN	1
30 #define INT3496_GPIO_USB_MUX	2
31 #define DEBOUNCE_TIME		msecs_to_jiffies(50)
32 
33 struct int3496_data {
34 	struct device *dev;
35 	struct extcon_dev *edev;
36 	struct delayed_work work;
37 	struct gpio_desc *gpio_usb_id;
38 	struct gpio_desc *gpio_vbus_en;
39 	struct gpio_desc *gpio_usb_mux;
40 	int usb_id_irq;
41 };
42 
43 static const unsigned int int3496_cable[] = {
44 	EXTCON_USB_HOST,
45 	EXTCON_NONE,
46 };
47 
48 static const struct acpi_gpio_params id_gpios = { INT3496_GPIO_USB_ID, 0, false };
49 static const struct acpi_gpio_params vbus_gpios = { INT3496_GPIO_VBUS_EN, 0, false };
50 static const struct acpi_gpio_params mux_gpios = { INT3496_GPIO_USB_MUX, 0, false };
51 
52 static const struct acpi_gpio_mapping acpi_int3496_default_gpios[] = {
53 	/*
54 	 * Some platforms have a bug in ACPI GPIO description making IRQ
55 	 * GPIO to be output only. Ask the GPIO core to ignore this limit.
56 	 */
57 	{ "id-gpios", &id_gpios, 1, ACPI_GPIO_QUIRK_NO_IO_RESTRICTION },
58 	{ "vbus-gpios", &vbus_gpios, 1 },
59 	{ "mux-gpios", &mux_gpios, 1 },
60 	{ },
61 };
62 
63 static void int3496_do_usb_id(struct work_struct *work)
64 {
65 	struct int3496_data *data =
66 		container_of(work, struct int3496_data, work.work);
67 	int id = gpiod_get_value_cansleep(data->gpio_usb_id);
68 
69 	/* id == 1: PERIPHERAL, id == 0: HOST */
70 	dev_dbg(data->dev, "Connected %s cable\n", id ? "PERIPHERAL" : "HOST");
71 
72 	/*
73 	 * Peripheral: set USB mux to peripheral and disable VBUS
74 	 * Host: set USB mux to host and enable VBUS
75 	 */
76 	if (!IS_ERR(data->gpio_usb_mux))
77 		gpiod_direction_output(data->gpio_usb_mux, id);
78 
79 	if (!IS_ERR(data->gpio_vbus_en))
80 		gpiod_direction_output(data->gpio_vbus_en, !id);
81 
82 	extcon_set_state_sync(data->edev, EXTCON_USB_HOST, !id);
83 }
84 
85 static irqreturn_t int3496_thread_isr(int irq, void *priv)
86 {
87 	struct int3496_data *data = priv;
88 
89 	/* Let the pin settle before processing it */
90 	mod_delayed_work(system_wq, &data->work, DEBOUNCE_TIME);
91 
92 	return IRQ_HANDLED;
93 }
94 
95 static int int3496_probe(struct platform_device *pdev)
96 {
97 	struct device *dev = &pdev->dev;
98 	struct int3496_data *data;
99 	int ret;
100 
101 	ret = devm_acpi_dev_add_driver_gpios(dev, acpi_int3496_default_gpios);
102 	if (ret) {
103 		dev_err(dev, "can't add GPIO ACPI mapping\n");
104 		return ret;
105 	}
106 
107 	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
108 	if (!data)
109 		return -ENOMEM;
110 
111 	data->dev = dev;
112 	INIT_DELAYED_WORK(&data->work, int3496_do_usb_id);
113 
114 	data->gpio_usb_id = devm_gpiod_get(dev, "id", GPIOD_IN);
115 	if (IS_ERR(data->gpio_usb_id)) {
116 		ret = PTR_ERR(data->gpio_usb_id);
117 		dev_err(dev, "can't request USB ID GPIO: %d\n", ret);
118 		return ret;
119 	}
120 
121 	data->usb_id_irq = gpiod_to_irq(data->gpio_usb_id);
122 	if (data->usb_id_irq < 0) {
123 		dev_err(dev, "can't get USB ID IRQ: %d\n", data->usb_id_irq);
124 		return data->usb_id_irq;
125 	}
126 
127 	data->gpio_vbus_en = devm_gpiod_get(dev, "vbus", GPIOD_ASIS);
128 	if (IS_ERR(data->gpio_vbus_en))
129 		dev_info(dev, "can't request VBUS EN GPIO\n");
130 
131 	data->gpio_usb_mux = devm_gpiod_get(dev, "mux", GPIOD_ASIS);
132 	if (IS_ERR(data->gpio_usb_mux))
133 		dev_info(dev, "can't request USB MUX GPIO\n");
134 
135 	/* register extcon device */
136 	data->edev = devm_extcon_dev_allocate(dev, int3496_cable);
137 	if (IS_ERR(data->edev))
138 		return -ENOMEM;
139 
140 	ret = devm_extcon_dev_register(dev, data->edev);
141 	if (ret < 0) {
142 		dev_err(dev, "can't register extcon device: %d\n", ret);
143 		return ret;
144 	}
145 
146 	ret = devm_request_threaded_irq(dev, data->usb_id_irq,
147 					NULL, int3496_thread_isr,
148 					IRQF_SHARED | IRQF_ONESHOT |
149 					IRQF_TRIGGER_RISING |
150 					IRQF_TRIGGER_FALLING,
151 					dev_name(dev), data);
152 	if (ret < 0) {
153 		dev_err(dev, "can't request IRQ for USB ID GPIO: %d\n", ret);
154 		return ret;
155 	}
156 
157 	/* process id-pin so that we start with the right status */
158 	queue_delayed_work(system_wq, &data->work, 0);
159 	flush_delayed_work(&data->work);
160 
161 	platform_set_drvdata(pdev, data);
162 
163 	return 0;
164 }
165 
166 static int int3496_remove(struct platform_device *pdev)
167 {
168 	struct int3496_data *data = platform_get_drvdata(pdev);
169 
170 	devm_free_irq(&pdev->dev, data->usb_id_irq, data);
171 	cancel_delayed_work_sync(&data->work);
172 
173 	return 0;
174 }
175 
176 static const struct acpi_device_id int3496_acpi_match[] = {
177 	{ "INT3496" },
178 	{ }
179 };
180 MODULE_DEVICE_TABLE(acpi, int3496_acpi_match);
181 
182 static struct platform_driver int3496_driver = {
183 	.driver = {
184 		.name = "intel-int3496",
185 		.acpi_match_table = int3496_acpi_match,
186 	},
187 	.probe = int3496_probe,
188 	.remove = int3496_remove,
189 };
190 
191 module_platform_driver(int3496_driver);
192 
193 MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
194 MODULE_DESCRIPTION("Intel INT3496 ACPI device extcon driver");
195 MODULE_LICENSE("GPL");
196