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    SubjectRe: [PATCH v3 1/7] extcon: usb-gpio: Introduce gpio usb extcon driver
    Hi Roger,

    On 01/30/2015 11:03 PM, Roger Quadros wrote:
    > On 30/01/15 02:11, Chanwoo Choi wrote:
    >> Hi Roger,
    >>
    >> On 01/28/2015 09:15 PM, Roger Quadros wrote:
    >>> This driver observes the USB ID pin connected over a GPIO and
    >>> updates the USB cable extcon states accordingly.
    >>>
    >>> The existing GPIO extcon driver is not suitable for this purpose
    >>> as it needs to be taught to understand USB cable states and it
    >>> can't handle more than one cable per instance.
    >>>
    >>> For the USB case we need to handle 2 cable states.
    >>> 1) USB (attach/detach)
    >>> 2) USB-Host (attach/detach)
    >>>
    >>> This driver can be easily updated in the future to handle VBUS
    >>> events in case it happens to be available on GPIO for any platform.
    >>>
    >>> Signed-off-by: Roger Quadros <rogerq@ti.com>
    >>> ---
    >>> v3:
    >>> - removed IRQF_NO_SUSPEND flag. Added IRQF_TRIGGER_RISING and
    >>> IRQF_TRIGGER_FALLING
    >>> - Added disable_irq() to suspend() and enable_irq() to resume()
    >>>
    >>> .../devicetree/bindings/extcon/extcon-usb-gpio.txt | 18 ++
    >>> drivers/extcon/Kconfig | 7 +
    >>> drivers/extcon/Makefile | 1 +
    >>> drivers/extcon/extcon-usb-gpio.c | 233 +++++++++++++++++++++
    >>> 4 files changed, 259 insertions(+)
    >>> create mode 100644 Documentation/devicetree/bindings/extcon/extcon-usb-gpio.txt
    >>> create mode 100644 drivers/extcon/extcon-usb-gpio.c
    >>>
    >>> diff --git a/Documentation/devicetree/bindings/extcon/extcon-usb-gpio.txt b/Documentation/devicetree/bindings/extcon/extcon-usb-gpio.txt
    >>> new file mode 100644
    >>> index 0000000..85fe6b0
    >>> --- /dev/null
    >>> +++ b/Documentation/devicetree/bindings/extcon/extcon-usb-gpio.txt
    >>> @@ -0,0 +1,18 @@
    >>> +USB GPIO Extcon device
    >>> +
    >>> +This is a virtual device used to generate USB cable states from the USB ID pin
    >>> +connected to a GPIO pin.
    >>> +
    >>> +Required properties:
    >>> +- compatible: Should be "linux,extcon-usb-gpio"
    >>> +- id-gpio: gpio for USB ID pin. See gpio binding.
    >>> +
    >>> +Example:
    >>> + extcon_usb1 {
    >>> + compatible = "linux,extcon-usb-gpio";
    >>> + id-gpio = <&gpio6 1 GPIO_ACTIVE_HIGH>;
    >>> + }
    >>> +
    >>> + &omap_dwc3_1 {
    >>> + extcon = <&extcon_usb1>;
    >>> + };
    >>> diff --git a/drivers/extcon/Kconfig b/drivers/extcon/Kconfig
    >>> index 6a1f7de..fd11536 100644
    >>> --- a/drivers/extcon/Kconfig
    >>> +++ b/drivers/extcon/Kconfig
    >>> @@ -93,4 +93,11 @@ config EXTCON_SM5502
    >>> Silicon Mitus SM5502. The SM5502 is a USB port accessory
    >>> detector and switch.
    >>>
    >>> +config EXTCON_USB_GPIO
    >>> + tristate "USB GPIO extcon support"
    >>> + select GPIOLIB
    >>> + help
    >>> + Say Y here to enable GPIO based USB cable detection extcon support.
    >>> + Used typically if GPIO is used for USB ID pin detection.
    >>> +
    >>> endif # MULTISTATE_SWITCH
    >>> diff --git a/drivers/extcon/Makefile b/drivers/extcon/Makefile
    >>> index 0370b42..6a08a98 100644
    >>> --- a/drivers/extcon/Makefile
    >>> +++ b/drivers/extcon/Makefile
    >>> @@ -12,3 +12,4 @@ obj-$(CONFIG_EXTCON_MAX8997) += extcon-max8997.o
    >>> obj-$(CONFIG_EXTCON_PALMAS) += extcon-palmas.o
    >>> obj-$(CONFIG_EXTCON_RT8973A) += extcon-rt8973a.o
    >>> obj-$(CONFIG_EXTCON_SM5502) += extcon-sm5502.o
    >>> +obj-$(CONFIG_EXTCON_USB_GPIO) += extcon-usb-gpio.o
    >>> diff --git a/drivers/extcon/extcon-usb-gpio.c b/drivers/extcon/extcon-usb-gpio.c
    >>> new file mode 100644
    >>> index 0000000..99a58b2
    >>> --- /dev/null
    >>> +++ b/drivers/extcon/extcon-usb-gpio.c
    >>> @@ -0,0 +1,233 @@
    >>> +/**
    >>> + * drivers/extcon/extcon-usb-gpio.c - USB GPIO extcon driver
    >>> + *
    >>> + * Copyright (C) 2015 Texas Instruments Incorporated - http://www.ti.com
    >>> + * Author: Roger Quadros <rogerq@ti.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/extcon.h>
    >>> +#include <linux/init.h>
    >>> +#include <linux/interrupt.h>
    >>> +#include <linux/irq.h>
    >>> +#include <linux/kernel.h>
    >>> +#include <linux/module.h>
    >>> +#include <linux/of_gpio.h>
    >>> +#include <linux/platform_device.h>
    >>> +#include <linux/slab.h>
    >>> +#include <linux/workqueue.h>
    >>> +
    >>> +#define USB_GPIO_DEBOUNCE_MS 20 /* ms */
    >>> +
    >>> +struct usb_extcon_info {
    >>> + struct device *dev;
    >>> + struct extcon_dev *edev;
    >>> +
    >>> + struct gpio_desc *id_gpiod;
    >>> + int id_irq;
    >>> + bool id_irqwake; /* ID wakeup enabled flag */
    >>> +
    >>> + unsigned long debounce_jiffies;
    >>> + struct delayed_work wq_detcable;
    >>> +};
    >>> +
    >>> +/* List of detectable cables */
    >>> +enum {
    >>> + EXTCON_CABLE_USB = 0,
    >>> + EXTCON_CABLE_USB_HOST,
    >>> +
    >>> + EXTCON_CABLE_END,
    >>> +};
    >>> +
    >>> +static const char *usb_extcon_cable[] = {
    >>> + [EXTCON_CABLE_USB] = "USB",
    >>> + [EXTCON_CABLE_USB_HOST] = "USB-Host",
    >>
    >> I'll use the defined name for extcon cable name as soon because
    >> it has potential isseu about the conflict of extcon cable name between subsystems.
    >> So, I recommend to use a captical letter as "USB-HOST" instead of "USB-Host".
    >> If other extcon driver don't use the captical letter, I'll fix it.
    >
    > Did you see patch 2 in this series?
    > In that I had fixed all instances to use "USB-Host" based on
    > http://lxr.free-electrons.com/source/drivers/extcon/extcon-class.c#L45
    >
    > What do you suggest?
    > Skip patch 2 and convert all "USB-Host" to "USB-HOST"?

    I replied my opinion about this on following patch[1].
    [1] Re: [PATCH v2 2/7] usb: extcon: Fix USB-Host cable name

    Thanks,
    Chanwoo Choi



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