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Message-id: <56721AFE.9020103@samsung.com>
Date: Thu, 17 Dec 2015 11:16:30 +0900
From: Chanwoo Choi <cw00.choi@...sung.com>
To: Sergei Shtylyov <sergei.shtylyov@...entembedded.com>,
robh+dt@...nel.org, pawel.moll@....com, mark.rutland@....com,
ijc+devicetree@...lion.org.uk, galak@...eaurora.org,
myungjoo.ham@...sung.com, devicetree@...r.kernel.org,
linux-kernel@...r.kernel.org
Cc: linux-sh@...r.kernel.org, linux-usb@...r.kernel.org
Subject: Re: [PATCH v3] extcon: add Maxim MAX3355 driver
Hi Sergei,
On 2015년 12월 17일 03:07, 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.
>
> Signed-off-by: Sergei Shtylyov <sergei.shtylyov@...entembedded.com>
>
> ---
> Changes in version 3:
> - reformatted the change log.
>
> 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: renesas/Documentation/devicetree/bindings/extcon/extcon-max3355.txt
> ===================================================================
> --- /dev/null
> +++ renesas/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: renesas/drivers/extcon/Kconfig
> ===================================================================
> --- renesas.orig/drivers/extcon/Kconfig
> +++ renesas/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: renesas/drivers/extcon/Makefile
> ===================================================================
> --- renesas.orig/drivers/extcon/Makefile
> +++ renesas/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: renesas/drivers/extcon/extcon-max3355.c
> ===================================================================
> --- /dev/null
> +++ renesas/drivers/extcon/extcon-max3355.c
> @@ -0,0 +1,153 @@
> +/*
> + * Maxim Integrated MAX3355 USB OTG chip extcon driver
> + *
> + * Copyright (C) 2014 Cogent Embedded, Inc.
2014 -> 2015
> + * Author: Sergei Shtylyov <sergei.shtylyov@...entembedded.com>
> + *
> + * 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);
You don't need to set the name of extcon device.
Instead, the extcon_dev_register() will set it.
> +
> + 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;
> + }
I recommend that you reorder the init code in probe() as following:
1. Allocate the memory of max3355_data *data.
2. Parse and initialize the gpio (id, shdn)
3. Allocate the memory of extcon_dev and register it.
4. Request the interrupt.
> +
> + 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,
You don't need to add the 'owner'.
> + },
> +};
> +
> +module_platform_driver(max3355_driver);
> +
> +MODULE_AUTHOR("Sergei Shtylyov <sergei.shtylyov@...entembedded.com>");
> +MODULE_DESCRIPTION("Maxim MAX3355 extcon driver");
> +MODULE_LICENSE("GPL v2");
Thanks,
Chanwoo Choi
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