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Subject[PATCH v2] extcon: int3496: Add Intel INT3496 ACPI device extcon driver
Date
From: David Cohen <david.a.cohen@intel.com>

Add an extcon driver for USB OTG ports controlled by an Intel INT3496
ACPI device (e.g. Baytrail, Cherrytrail devices).

Signed-off-by: David Cohen <david.a.cohen@intel.com>
[hdgoede@redhat.com: Port to current kernel, cleanup, submit upstream]
[hdgoede@redhat.com: Add Documentation/extcon/intel-int3496.txt]
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
Changes in v2:
-Rename to extcon-intel-int3496
-Add documentation: Documentation/extcon/intel-int3496.txt
-Fold usb_otg_set_port() into usb_otg_do_usb_id()
-Unify / cleanup error messages
---
Documentation/extcon/intel-int3496.txt | 22 ++++
drivers/extcon/Kconfig | 10 ++
drivers/extcon/Makefile | 1 +
drivers/extcon/extcon-intel-int3496.c | 179 +++++++++++++++++++++++++++++++++
4 files changed, 212 insertions(+)
create mode 100644 Documentation/extcon/intel-int3496.txt
create mode 100644 drivers/extcon/extcon-intel-int3496.c

diff --git a/Documentation/extcon/intel-int3496.txt b/Documentation/extcon/intel-int3496.txt
new file mode 100644
index 0000000..af0b366
--- /dev/null
+++ b/Documentation/extcon/intel-int3496.txt
@@ -0,0 +1,22 @@
+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
diff --git a/drivers/extcon/Kconfig b/drivers/extcon/Kconfig
index 04788d9..1ed3860 100644
--- a/drivers/extcon/Kconfig
+++ b/drivers/extcon/Kconfig
@@ -35,6 +35,16 @@ config EXTCON_AXP288
Say Y here to enable support for USB peripheral detection
and USB MUX switching by X-Power AXP288 PMIC.

+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_GPIO
tristate "GPIO extcon support"
depends on GPIOLIB || COMPILE_TEST
diff --git a/drivers/extcon/Makefile b/drivers/extcon/Makefile
index 31a0a99..237ac3f 100644
--- a/drivers/extcon/Makefile
+++ b/drivers/extcon/Makefile
@@ -8,6 +8,7 @@ obj-$(CONFIG_EXTCON_ADC_JACK) += extcon-adc-jack.o
obj-$(CONFIG_EXTCON_ARIZONA) += extcon-arizona.o
obj-$(CONFIG_EXTCON_AXP288) += extcon-axp288.o
obj-$(CONFIG_EXTCON_GPIO) += extcon-gpio.o
+obj-$(CONFIG_EXTCON_INTEL_INT3496) += extcon-intel-int3496.o
obj-$(CONFIG_EXTCON_MAX14577) += extcon-max14577.o
obj-$(CONFIG_EXTCON_MAX3355) += extcon-max3355.o
obj-$(CONFIG_EXTCON_MAX77693) += extcon-max77693.o
diff --git a/drivers/extcon/extcon-intel-int3496.c b/drivers/extcon/extcon-intel-int3496.c
new file mode 100644
index 0000000..a3131b0
--- /dev/null
+++ b/drivers/extcon/extcon-intel-int3496.c
@@ -0,0 +1,179 @@
+/*
+ * 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");
--
2.9.3
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