Re: [PATCH v2] extcon: add Maxim MAX3355 driver

[Rob Herring]

On Sat, Dec 12, 2015 at 02:22:06AM +0300, Sergei Shtylyov wrote:
> Maxim  Integrated MAX3355E chip integrates a  charge pump and comparators to
> enable a system with an integrated USB OTG dual-role transceiver to function
> as  an USB  OTG dual-role device.  In addition  to sensing/controlling Vbus,
> the chip also passes thru the ID signal  from the USB  OTG connector.
> On some Renesas boards,  this signal is  just fed into the SoC thru a GPIO
> pin --  there's no real  OTG controller, only host and gadget USB controllers
> sharing the same USB bus; however, we'd  like to allow host or gadget drivers
> to be loaded depending on the cable type,  hence the need for the MAX3355
> extcon driver. The Vbus status signals are also  wired to GPIOs (however, we
> aren't currently interested in them),  the OFFVBUS# signal is controlled  by
> the host controllers, there's  also the SHDN# signal wired to a GPIO, it
> should be driven high for the  normal operation.

As multiple people have said, fix the spacing here.

> 
> Signed-off-by: Sergei Shtylyov <sergei.shtylyov@xxxxxxxxxxxxxxxxxx>
> 
> ---
> The patch is against the 'extcon-next' branch of the 'extcon.git' repo.
> 
> Changes in version 2:
> - added the USB gadget cable support;
> - added the remove() driver method which drives SHDN# GPIO low to save power;
> - dropped vendor prefix from the ID GPIO property name;
> - changed the GPIO property name suffix to "-gpios";
> - switched to usign extcon_set_cable_state_() API;
> - switched to using the gpiod/sleeping 'gpiolib' APIs;
> - addded error messages to max3355_probe();
> - added IRQF_NO_SUSPEND flasg to the devm_request_threaded_irq() call;
> - renamed 'ret' variable to 'err' in max3355_probe();
> - expanded the Kconfig entry help text;
> - added vendor name to the patch summary, the bindings document, the Kconfig
>   entry, the driver heading comment, the module description, and the change log;
> - fixed up and reformatted the change log.
> 
>  Documentation/devicetree/bindings/extcon/extcon-max3355.txt |   21 +
>  drivers/extcon/Kconfig                                      |    8 
>  drivers/extcon/Makefile                                     |    1 
>  drivers/extcon/extcon-max3355.c                             |  153 ++++++++++++
>  4 files changed, 183 insertions(+)
> 
> Index: extcon/Documentation/devicetree/bindings/extcon/extcon-max3355.txt
> ===================================================================
> --- /dev/null
> +++ extcon/Documentation/devicetree/bindings/extcon/extcon-max3355.txt
> @@ -0,0 +1,21 @@
> +Maxim Integrated MAX3355 USB OTG chip
> +-------------------------------------
> +
> +MAX3355 integrates a charge pump and comparators to enable a system with an
> +integrated USB OTG dual-role transceiver to function as a USB OTG dual-role
> +device.
> +
> +Required properties:
> +- compatible: should be "maxim,max3355";
> +- maxim,shdn-gpios: should contain a phandle and GPIO specifier for the GPIO pin
> +  connected to the MAX3355's SHDN# pin;
> +- id-gpios: should contain a phandle and GPIO specifier for the GPIO pin
> +  connected to the MAX3355's ID_OUT pin.
> +
> +Example (Koelsch board):
> +
> +	usb-otg {
> +		compatible = "maxim,max3355";
> +		maxim,shdn-gpios = <&gpio2 4 GPIO_ACTIVE_LOW>;
> +		id-gpios = <&gpio5 31 GPIO_ACTIVE_HIGH>;
> +	};
> Index: extcon/drivers/extcon/Kconfig
> ===================================================================
> --- extcon.orig/drivers/extcon/Kconfig
> +++ extcon/drivers/extcon/Kconfig
> @@ -52,6 +52,14 @@ config EXTCON_MAX14577
>  	  Maxim MAX14577/77836. The MAX14577/77836 MUIC is a USB port accessory
>  	  detector and switch.
>  
> +config EXTCON_MAX3355
> +	tristate "Maxim MAX3355 USB OTG EXTCON Support"
> +	help
> +	  If you say yes here you get support for the USB OTG role detection by
> +	  MAX3355. The MAX3355 chip integrates a charge pump and comparators to
> +	  enable a system with an integrated USB OTG dual-role transceiver to
> +	  function as an USB OTG dual-role device.
> +
>  config EXTCON_MAX77693
>  	tristate "Maxim MAX77693 EXTCON Support"
>  	depends on MFD_MAX77693 && INPUT
> Index: extcon/drivers/extcon/Makefile
> ===================================================================
> --- extcon.orig/drivers/extcon/Makefile
> +++ extcon/drivers/extcon/Makefile
> @@ -8,6 +8,7 @@ obj-$(CONFIG_EXTCON_ARIZONA)	+= extcon-a
>  obj-$(CONFIG_EXTCON_AXP288)	+= extcon-axp288.o
>  obj-$(CONFIG_EXTCON_GPIO)	+= extcon-gpio.o
>  obj-$(CONFIG_EXTCON_MAX14577)	+= extcon-max14577.o
> +obj-$(CONFIG_EXTCON_MAX3355)	+= extcon-max3355.o
>  obj-$(CONFIG_EXTCON_MAX77693)	+= extcon-max77693.o
>  obj-$(CONFIG_EXTCON_MAX77843)	+= extcon-max77843.o
>  obj-$(CONFIG_EXTCON_MAX8997)	+= extcon-max8997.o
> Index: extcon/drivers/extcon/extcon-max3355.c
> ===================================================================
> --- /dev/null
> +++ extcon/drivers/extcon/extcon-max3355.c
> @@ -0,0 +1,153 @@
> +/*
> + * Maxim Integrated MAX3355 USB OTG chip extcon driver
> + *
> + * Copyright (C) 2014 Cogent Embedded, Inc.
> + * Author: Sergei Shtylyov <sergei.shtylyov@xxxxxxxxxxxxxxxxxx>
> + *
> + * This software is licensed under the terms of the GNU General Public
> + * License version 2, as published by the Free Software Foundation, and
> + * may be copied, distributed, and modified under those terms.
> + */
> +
> +#include <linux/extcon.h>
> +#include <linux/gpio.h>
> +#include <linux/init.h>
> +#include <linux/interrupt.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>
> +
> +struct max3355_data {
> +	struct extcon_dev *edev;
> +	struct gpio_desc *id_gpiod;
> +	struct gpio_desc *shdn_gpiod;
> +};
> +
> +static const unsigned int max3355_cable[] = {
> +	EXTCON_USB,
> +	EXTCON_USB_HOST,
> +	EXTCON_NONE,
> +};
> +
> +static irqreturn_t max3355_id_irq(int irq, void *dev_id)
> +{
> +	struct max3355_data *data = dev_id;
> +	int id = gpiod_get_value_cansleep(data->id_gpiod);
> +
> +	if (id) {
> +		/*
> +		 * ID = 1 means USB HOST cable detached.
> +		 * As we don't have event for USB peripheral cable attached,
> +		 * we simulate USB peripheral attach here.
> +		 */
> +		extcon_set_cable_state_(data->edev, EXTCON_USB_HOST, false);
> +		extcon_set_cable_state_(data->edev, EXTCON_USB, true);
> +	} else {
> +		/*
> +		 * ID = 0 means USB HOST cable attached.
> +		 * As we don't have event for USB peripheral cable detached,
> +		 * we simulate USB peripheral detach here.
> +		 */
> +		extcon_set_cable_state_(data->edev, EXTCON_USB, false);
> +		extcon_set_cable_state_(data->edev, EXTCON_USB_HOST, true);
> +	}
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static int max3355_probe(struct platform_device *pdev)
> +{
> +	struct device_node *np = pdev->dev.of_node;
> +	struct max3355_data *data;
> +	struct gpio_desc *gpiod;
> +	int irq, err;
> +
> +	data = devm_kzalloc(&pdev->dev, sizeof(struct max3355_data),
> +			    GFP_KERNEL);
> +	if (!data)
> +		return -ENOMEM;
> +
> +	data->edev = devm_extcon_dev_allocate(&pdev->dev, max3355_cable);
> +	if (IS_ERR(data->edev)) {
> +		dev_err(&pdev->dev, "failed to allocate extcon device\n");
> +		return PTR_ERR(data->edev);
> +	}
> +	data->edev->name = kstrdup(np->name, GFP_KERNEL);
> +
> +	gpiod = devm_gpiod_get(&pdev->dev, "id", GPIOD_IN);
> +	if (IS_ERR(gpiod)) {
> +		dev_err(&pdev->dev, "failed to get ID_OUT GPIO\n");
> +		return PTR_ERR(gpiod);
> +	}
> +	data->id_gpiod = gpiod;
> +
> +	gpiod = devm_gpiod_get(&pdev->dev, "maxim,shdn", GPIOD_OUT_HIGH);
> +	if (IS_ERR(gpiod)) {
> +		dev_err(&pdev->dev, "failed to get SHDN# GPIO\n");
> +		return PTR_ERR(gpiod);
> +	}
> +	data->shdn_gpiod = gpiod;
> +
> +	err = devm_extcon_dev_register(&pdev->dev, data->edev);
> +	if (err < 0) {
> +		dev_err(&pdev->dev, "failed to register extcon device\n");
> +		return err;
> +	}
> +
> +	irq = gpiod_to_irq(data->id_gpiod);
> +	if (irq < 0) {
> +		dev_err(&pdev->dev, "failed to translate ID_OUT GPIO to IRQ\n");
> +		return irq;
> +	}
> +
> +	err = devm_request_threaded_irq(&pdev->dev, irq, NULL, max3355_id_irq,
> +					IRQF_ONESHOT | IRQF_NO_SUSPEND |
> +					IRQF_TRIGGER_RISING |
> +					IRQF_TRIGGER_FALLING,
> +					pdev->name, data);
> +	if (err < 0) {
> +		dev_err(&pdev->dev, "failed to request ID_OUT IRQ\n");
> +		return err;
> +	}
> +
> +	platform_set_drvdata(pdev, data);
> +
> +	/* Perform initial detection */
> +	max3355_id_irq(irq, data);
> +
> +	return 0;
> +}
> +
> +static int max3355_remove(struct platform_device *pdev)
> +{
> +	struct max3355_data *data = platform_get_drvdata(pdev);
> +
> +	gpiod_set_value_cansleep(data->shdn_gpiod, 0);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id max3355_match_table[] = {
> +	{ .compatible = "maxim,max3355", },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(of, max3355_match_table);
> +
> +static struct platform_driver max3355_driver = {
> +	.probe		= max3355_probe,
> +	.remove		= max3355_remove,
> +	.driver		= {
> +		.name	= "extcon-max3355",
> +		.of_match_table = max3355_match_table,
> +		.owner	= THIS_MODULE,
> +	},
> +};
> +
> +module_platform_driver(max3355_driver);
> +
> +MODULE_AUTHOR("Sergei Shtylyov <sergei.shtylyov@xxxxxxxxxxxxxxxxxx>");
> +MODULE_DESCRIPTION("Maxim MAX3355 extcon driver");
> +MODULE_LICENSE("GPL v2");
> 
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