Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751693AbaLWTjM (ORCPT ); Tue, 23 Dec 2014 14:39:12 -0500 Received: from mga01.intel.com ([192.55.52.88]:9488 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750725AbaLWTjK (ORCPT ); Tue, 23 Dec 2014 14:39:10 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.07,633,1413270000"; d="scan'208";a="642068522" Date: Tue, 23 Dec 2014 11:40:23 -0800 From: David Cohen To: Peter Chen Cc: myungjoo.ham@samsung.com, cw00.choi@samsung.com, linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org, baolu.lu@linux.intel.com Subject: Re: [RFC/PATCH] extcon: otg_gpio: add driver for USB OTG port controlled by GPIO(s) Message-ID: <20141223194022.GA13792@psi-dev26.jf.intel.com> References: <1419288217-19262-1-git-send-email-david.a.cohen@linux.intel.com> <20141223012517.GC11551@shlinux2> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20141223012517.GC11551@shlinux2> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Peter, Thanks for the review. On Tue, Dec 23, 2014 at 09:25:18AM +0800, Peter Chen wrote: > On Mon, Dec 22, 2014 at 02:43:37PM -0800, David Cohen wrote: > > Some platforms have an USB OTG port fully (or partially) controlled by > > GPIOs: > > > > (1) USB ID is connected directly to GPIO > > > > Optionally: > > (2) VBUS is enabled by a GPIO (when ID is grounded) > > (3) Platform has 2 USB controllers connected to same port: one for > > device and one for host role. D+/- are switched between phys > > by GPIO. > > Would you explain how it works? Choosing controller runtime? Both controllers are (indirectly) connected to the same micro B port. The D+/- goes from the port to a switch operated by a GPIO. From the switch, D+/- may go to Host controller's phy or Device controller's phy. Depends on the GPIO level. > > > > > As per initial version, this driver has the duty to control whether > > USB-Host cable is plugged in or not: > > You mean Micro-AB cable, right? In my case I'd say micro B. But USB-Host would be any cable or combination of cables where USB ID is grounded. > > > - If yes, OTG port is configured for host role > > - If no, by standard, the OTG port is configured for device role > > > > Signed-off-by: David Cohen > > --- > > > > Hi, > > > > Some Intel Bay Trail boards have an unusual way to handle the USB OTG port: > > - The USB ID pin is connected directly to GPIO on SoC > > - When in host role, VBUS is provided by enabling a GPIO > > - Device and host roles are supported by 2 independent controllers with D+/- > > pins from port switched between different phys according a GPIO level. > > > > The ACPI table describes this USB port as a (virtual) device with all the > > necessary GPIOs. This driver implements support to this virtual device as an > > extcon class driver. All drivers that depend on the USB OTG port state (USB phy, > > PMIC, charge detection) will listen to extcon events. > > > > Comments are welcome. > > > > Br, David > > --- > > > > drivers/extcon/Kconfig | 8 ++ > > drivers/extcon/Makefile | 1 + > > drivers/extcon/extcon-otg_gpio.c | 200 +++++++++++++++++++++++++++++++++++++++ > > 3 files changed, 209 insertions(+) > > create mode 100644 drivers/extcon/extcon-otg_gpio.c > > > > diff --git a/drivers/extcon/Kconfig b/drivers/extcon/Kconfig > > index 6a1f7de6fa54..e8010cda4642 100644 > > --- a/drivers/extcon/Kconfig > > +++ b/drivers/extcon/Kconfig > > @@ -93,4 +93,12 @@ config EXTCON_SM5502 > > Silicon Mitus SM5502. The SM5502 is a USB port accessory > > detector and switch. > > > > +config EXTCON_OTG_GPIO > > + tristate "VIRTUAL USB OTG PORT support" > > + depends on GPIOLIB > > + help > > + Say Y here to enable support for virtual USB OTG port device > > + controlled by GPIOs. This driver can be used when at least USB ID pin > > + is connected directly to GPIO. > > + > > endif # MULTISTATE_SWITCH > > diff --git a/drivers/extcon/Makefile b/drivers/extcon/Makefile > > index 0370b42e5a27..9e81088c6584 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_OTG_GPIO) += extcon-otg_gpio.o > > diff --git a/drivers/extcon/extcon-otg_gpio.c b/drivers/extcon/extcon-otg_gpio.c > > new file mode 100644 > > index 000000000000..c5ee765a5f4f > > --- /dev/null > > +++ b/drivers/extcon/extcon-otg_gpio.c > > @@ -0,0 +1,200 @@ > > +/* > > + * Virtual USB OTG Port driver controlled by gpios > > + * > > + * Copyright (c) 2014, Intel Corporation. > > + * Author: David Cohen > > + * > > + * 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 > > +#include > > +#include > > +#include > > +#include > > + > > +#define DRV_NAME "usb_otg_port" > > + > > +struct vuport { > > + struct device *dev; > > + struct gpio_desc *gpio_vbus_en; > > + struct gpio_desc *gpio_usb_id; > > + struct gpio_desc *gpio_usb_mux; > > + > > + struct extcon_dev edev; > > +}; > > + > > +static const char *const vuport_extcon_cable[] = { > > + [0] = "USB-Host", > > + NULL, > > +}; > > + > > +/* > > + * If id == 1, USB port should be set to peripheral > > + * if id == 0, USB port should be set to host > > + * > > + * Peripheral: set USB mux to peripheral and disable VBUS > > + * Host: set USB mux to host and enable VBUS > > + */ > > +static void vuport_set_port(struct vuport *vup, int id) > > +{ > > + int mux_val = id; > > + int vbus_val = !id; > > + > > + if (!IS_ERR(vup->gpio_usb_mux)) > > + gpiod_direction_output(vup->gpio_usb_mux, mux_val); > > + > > + if (!IS_ERR(vup->gpio_vbus_en)) > > + gpiod_direction_output(vup->gpio_vbus_en, vbus_val); > > +} > > + > > +static void vuport_do_usb_id(struct vuport *vup) > > +{ > > + int id = gpiod_get_value(vup->gpio_usb_id); > > + > > + dev_info(vup->dev, "USB PORT ID: %s\n", id ? "PERIPHERAL" : "HOST"); > > dev_dbg Agreed. > > > + > > + /* > > + * id == 1: PERIPHERAL > > + * id == 0: HOST > > + */ > > + vuport_set_port(vup, id); > > + > > + /* > > + * id == 0: HOST connected > > + * id == 1: Host disconnected > > + */ > > + extcon_set_cable_state(&vup->edev, "USB-Host", !id); > > +} > > + > > +static irqreturn_t vuport_thread_isr(int irq, void *priv) > > +{ > > + struct vuport *vup = priv; > > + > > + vuport_do_usb_id(vup); > > + return IRQ_HANDLED; > > +} > > + > > +static irqreturn_t vuport_isr(int irq, void *priv) > > +{ > > + return IRQ_WAKE_THREAD; > > +} > > + > > +#define VUPORT_GPIO_USB_ID 0 > > +#define VUPORT_GPIO_VBUS_EN 1 > > +#define VUPORT_GPIO_USB_MUX 2 > > +static int vuport_probe(struct platform_device *pdev) > > +{ > > + struct device *dev = &pdev->dev; > > + struct vuport *vup; > > + int ret; > > + > > + vup = devm_kzalloc(dev, sizeof(*vup), GFP_KERNEL); > > + if (!vup) { > > + dev_err(dev, "cannot allocate private data\n"); > > + return -ENOMEM; > > + } > > + vup->dev = dev; > > + > > + vup->gpio_usb_id = devm_gpiod_get_index(dev, "id", VUPORT_GPIO_USB_ID); > > + if (IS_ERR(vup->gpio_usb_id)) { > > + dev_err(dev, "cannot request USB ID GPIO: ret = %ld\n", > > + PTR_ERR(vup->gpio_usb_id)); > > + return PTR_ERR(vup->gpio_usb_id); > > + } > > + > > + ret = gpiod_direction_input(vup->gpio_usb_id); > > + if (ret < 0) { > > + dev_err(dev, "cannot set input direction to USB ID GPIO: ret = %d\n", > > + ret); > > + return ret; > > + } > > + > > + vup->gpio_vbus_en = devm_gpiod_get_index(dev, "vbus en", > > + VUPORT_GPIO_VBUS_EN); > > + if (IS_ERR(vup->gpio_vbus_en)) > > + dev_info(dev, "cannot request VBUS EN GPIO, skipping it.\n"); > > + > > + vup->gpio_usb_mux = devm_gpiod_get_index(dev, "usb mux", > > + VUPORT_GPIO_USB_MUX); > > + if (IS_ERR(vup->gpio_usb_mux)) > > + dev_info(dev, "cannot request USB USB MUX, skipping it.\n"); > > Using dev_err That's not really an error, although the IS_ERR() suggests otherwise. The driver works well if a board doesn't need this mux (I'll add a comment to state that clear). IMHO either keep dev_info or use dev_dgb instead? Br, David > > > + > > + /* register extcon device */ > > + vup->edev.dev.parent = dev; > > + vup->edev.supported_cable = vuport_extcon_cable; > > + ret = extcon_dev_register(&vup->edev); > > + if (ret < 0) { > > + dev_err(dev, "failed to register extcon device: ret = %d\n", > > + ret); > > + return ret; > > + } > > + > > + ret = devm_request_threaded_irq(dev, gpiod_to_irq(vup->gpio_usb_id), > > + vuport_isr, vuport_thread_isr, > > + IRQF_SHARED | IRQF_TRIGGER_RISING | > > + IRQF_TRIGGER_FALLING, > > + dev_name(dev), vup); > > + if (ret < 0) { > > + dev_err(dev, "cannot request IRQ for USB ID GPIO: ret = %d\n", > > + ret); > > + goto irq_err; > > + } > > + vuport_do_usb_id(vup); > > + > > + platform_set_drvdata(pdev, vup); > > + > > + dev_info(dev, "driver successfully probed\n"); > > + > > + return 0; > > + > > +irq_err: > > + extcon_dev_unregister(&vup->edev); > > + > > + return ret; > > +} > > + > > +static int vuport_remove(struct platform_device *pdev) > > +{ > > + struct vuport *vup = platform_get_drvdata(pdev); > > + > > + extcon_dev_unregister(&vup->edev); > > + return 0; > > +} > > + > > +static struct acpi_device_id vuport_acpi_match[] = { > > + { "INT3496" }, > > + { } > > +}; > > +MODULE_DEVICE_TABLE(acpi, vuport_acpi_match); > > + > > +static struct platform_driver vuport_driver = { > > + .driver = { > > + .name = DRV_NAME, > > + .acpi_match_table = ACPI_PTR(vuport_acpi_match), > > + }, > > + .probe = vuport_probe, > > + .remove = vuport_remove, > > +}; > > + > > +static int __init vuport_init(void) > > +{ > > + return platform_driver_register(&vuport_driver); > > +} > > +subsys_initcall(vuport_init); > > + > > +static void __exit vuport_exit(void) > > +{ > > + platform_driver_unregister(&vuport_driver); > > +} > > +module_exit(vuport_exit); > > + > > +MODULE_LICENSE("GPL"); > > +MODULE_AUTHOR("David Cohen "); > > -- > > 2.1.1 > > > > -- > > Best Regards, > Peter Chen -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/