extcon: int3496: Add Intel INT3496 ACPI device extcon driver (2f556bdb) · Commits · e / devices / android_kernel_xiaomi_nabu

Documentation/extcon/intel-int3496.txt

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			Intel INT3496 ACPI device extcon driver documentation
			-----------------------------------------------------

			The Intel INT3496 ACPI device extcon driver is a driver for ACPI
			devices with an acpi-id of INT3496, such as found for example on
			Intel Baytrail and Cherrytrail tablets.

			This ACPI device describes how the OS can read the id-pin of the devices'
			USB-otg port, as well as how it optionally can enable Vbus output on the
			otg port and how it can optionally control the muxing of the data pins
			between an USB host and an USB peripheral controller.

			The ACPI devices exposes this functionality by returning an array with up
			to 3 gpio descriptors from its ACPI _CRS (Current Resource Settings) call:

			Index 0: The input gpio for the id-pin, this is always present and valid
			Index 1: The output gpio for enabling Vbus output from the device to the otg
			port, write 1 to enable the Vbus output (this gpio descriptor may
			be absent or invalid)
			Index 2: The output gpio for muxing of the data pins between the USB host and
			the USB peripheral controller, write 1 to mux to the peripheral
			controller

drivers/extcon/Kconfig

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	@@ -42,6 +42,16 @@ config EXTCON_GPIO
	Say Y here to enable GPIO based extcon support. Note that GPIO		Say Y here to enable GPIO based extcon support. Note that GPIO
	extcon supports single state per extcon instance.		extcon supports single state per extcon instance.

			config EXTCON_INTEL_INT3496
			tristate "Intel INT3496 ACPI device extcon driver"
			depends on GPIOLIB && ACPI
			help
			Say Y here to enable extcon support for USB OTG ports controlled by
			an Intel INT3496 ACPI device.

			This ACPI device is typically found on Intel Baytrail or Cherrytrail
			based tablets, or other Baytrail / Cherrytrail devices.

	config EXTCON_MAX14577		config EXTCON_MAX14577
	tristate "Maxim MAX14577/77836 EXTCON Support"		tristate "Maxim MAX14577/77836 EXTCON Support"
	depends on MFD_MAX14577		depends on MFD_MAX14577

drivers/extcon/Makefile

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	@@ -8,6 +8,7 @@ obj-$(CONFIG_EXTCON_ADC_JACK) += extcon-adc-jack.o
	obj-$(CONFIG_EXTCON_ARIZONA) += extcon-arizona.o		obj-$(CONFIG_EXTCON_ARIZONA) += extcon-arizona.o
	obj-$(CONFIG_EXTCON_AXP288) += extcon-axp288.o		obj-$(CONFIG_EXTCON_AXP288) += extcon-axp288.o
	obj-$(CONFIG_EXTCON_GPIO) += extcon-gpio.o		obj-$(CONFIG_EXTCON_GPIO) += extcon-gpio.o
			obj-$(CONFIG_EXTCON_INTEL_INT3496) += extcon-intel-int3496.o
	obj-$(CONFIG_EXTCON_MAX14577) += extcon-max14577.o		obj-$(CONFIG_EXTCON_MAX14577) += extcon-max14577.o
	obj-$(CONFIG_EXTCON_MAX3355) += extcon-max3355.o		obj-$(CONFIG_EXTCON_MAX3355) += extcon-max3355.o
	obj-$(CONFIG_EXTCON_MAX77693) += extcon-max77693.o		obj-$(CONFIG_EXTCON_MAX77693) += extcon-max77693.o

drivers/extcon/extcon-intel-int3496.c

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			/*
			* Intel INT3496 ACPI device extcon driver
			*
			* Copyright (c) 2016 Hans de Goede <hdegoede@redhat.com>
			*
			* Based on android x86 kernel code which is:
			*
			* Copyright (c) 2014, Intel Corporation.
			* Author: David Cohen <david.a.cohen@linux.intel.com>
			*
			* This program is free software; you can redistribute it and/or modify
			* it under the terms of the GNU General Public License version 2 as
			* published by the Free Software Foundation.
			*
			* This program is distributed in the hope that it will be useful,
			* but WITHOUT ANY WARRANTY; without even the implied warranty of
			* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
			* GNU General Public License for more details.
			*/

			#include <linux/acpi.h>
			#include <linux/extcon.h>
			#include <linux/gpio.h>
			#include <linux/interrupt.h>
			#include <linux/module.h>
			#include <linux/platform_device.h>

			#define INT3496_GPIO_USB_ID 0
			#define INT3496_GPIO_VBUS_EN 1
			#define INT3496_GPIO_USB_MUX 2
			#define DEBOUNCE_TIME msecs_to_jiffies(50)

			struct int3496_data {
			struct device *dev;
			struct extcon_dev *edev;
			struct delayed_work work;
			struct gpio_desc *gpio_usb_id;
			struct gpio_desc *gpio_vbus_en;
			struct gpio_desc *gpio_usb_mux;
			int usb_id_irq;
			};

			static const unsigned int int3496_cable[] = {
			EXTCON_USB_HOST,
			EXTCON_NONE,
			};

			static void int3496_do_usb_id(struct work_struct *work)
			{
			struct int3496_data *data =
			container_of(work, struct int3496_data, work.work);
			int id = gpiod_get_value_cansleep(data->gpio_usb_id);

			/* id == 1: PERIPHERAL, id == 0: HOST */
			dev_dbg(data->dev, "Connected %s cable\n", id ? "PERIPHERAL" : "HOST");

			/*
			* Peripheral: set USB mux to peripheral and disable VBUS
			* Host: set USB mux to host and enable VBUS
			*/
			if (!IS_ERR(data->gpio_usb_mux))
			gpiod_direction_output(data->gpio_usb_mux, id);

			if (!IS_ERR(data->gpio_vbus_en))
			gpiod_direction_output(data->gpio_vbus_en, !id);

			extcon_set_state_sync(data->edev, EXTCON_USB_HOST, !id);
			}

			static irqreturn_t int3496_thread_isr(int irq, void *priv)
			{
			struct int3496_data *data = priv;

			/* Let the pin settle before processing it */
			mod_delayed_work(system_wq, &data->work, DEBOUNCE_TIME);

			return IRQ_HANDLED;
			}

			static int int3496_probe(struct platform_device *pdev)
			{
			struct device *dev = &pdev->dev;
			struct int3496_data *data;
			int ret;

			data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
			if (!data)
			return -ENOMEM;

			data->dev = dev;
			INIT_DELAYED_WORK(&data->work, int3496_do_usb_id);

			data->gpio_usb_id = devm_gpiod_get_index(dev, "id",
			INT3496_GPIO_USB_ID,
			GPIOD_IN);
			if (IS_ERR(data->gpio_usb_id)) {
			ret = PTR_ERR(data->gpio_usb_id);
			dev_err(dev, "can't request USB ID GPIO: %d\n", ret);
			return ret;
			}

			data->usb_id_irq = gpiod_to_irq(data->gpio_usb_id);
			if (data->usb_id_irq <= 0) {
			dev_err(dev, "can't get USB ID IRQ: %d\n", data->usb_id_irq);
			return -EINVAL;
			}

			data->gpio_vbus_en = devm_gpiod_get_index(dev, "vbus en",
			INT3496_GPIO_VBUS_EN,
			GPIOD_ASIS);
			if (IS_ERR(data->gpio_vbus_en))
			dev_info(dev, "can't request VBUS EN GPIO\n");

			data->gpio_usb_mux = devm_gpiod_get_index(dev, "usb mux",
			INT3496_GPIO_USB_MUX,
			GPIOD_ASIS);
			if (IS_ERR(data->gpio_usb_mux))
			dev_info(dev, "can't request USB MUX GPIO\n");

			/* register extcon device */
			data->edev = devm_extcon_dev_allocate(dev, int3496_cable);
			if (IS_ERR(data->edev))
			return -ENOMEM;

			ret = devm_extcon_dev_register(dev, data->edev);
			if (ret < 0) {
			dev_err(dev, "can't register extcon device: %d\n", ret);
			return ret;
			}

			ret = devm_request_threaded_irq(dev, data->usb_id_irq,
			NULL, int3496_thread_isr,
			IRQF_SHARED \| IRQF_ONESHOT \|
			IRQF_TRIGGER_RISING \|
			IRQF_TRIGGER_FALLING,
			dev_name(dev), data);
			if (ret < 0) {
			dev_err(dev, "can't request IRQ for USB ID GPIO: %d\n", ret);
			return ret;
			}

			/* queue initial processing of id-pin */
			queue_delayed_work(system_wq, &data->work, 0);

			platform_set_drvdata(pdev, data);

			return 0;
			}

			static int int3496_remove(struct platform_device *pdev)
			{
			struct int3496_data *data = platform_get_drvdata(pdev);

			devm_free_irq(&pdev->dev, data->usb_id_irq, data);
			cancel_delayed_work_sync(&data->work);

			return 0;
			}

			static struct acpi_device_id int3496_acpi_match[] = {
			{ "INT3496" },
			{ }
			};
			MODULE_DEVICE_TABLE(acpi, int3496_acpi_match);

			static struct platform_driver int3496_driver = {
			.driver = {
			.name = "intel-int3496",
			.acpi_match_table = int3496_acpi_match,
			},
			.probe = int3496_probe,
			.remove = int3496_remove,
			};

			module_platform_driver(int3496_driver);

			MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
			MODULE_DESCRIPTION("Intel INT3496 ACPI device extcon driver");
			MODULE_LICENSE("GPL");