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Message-ID: <1595828558.23885.90.camel@mhfsdcap03>
Date: Mon, 27 Jul 2020 13:42:38 +0800
From: Chunfeng Yun <chunfeng.yun@...iatek.com>
To: Paul Cercueil <paul@...pouillou.net>
CC: Andy Shevchenko <andy.shevchenko@...il.com>,
Chanwoo Choi <cw00.choi@...sung.com>,
MyungJoo Ham <myungjoo.ham@...sung.com>,
"Greg Kroah-Hartman" <gregkh@...uxfoundation.org>, <od@...c.me>,
USB <linux-usb@...r.kernel.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [RESEND PATCH] usb: common: usb-conn-gpio: Register optional
charger
On Sun, 2020-07-26 at 12:27 +0200, Paul Cercueil wrote:
>
> Le dim. 26 juil. 2020 à 13:14, Andy Shevchenko
> <andy.shevchenko@...il.com> a écrit :
> > On Mon, Jun 22, 2020 at 1:51 AM Paul Cercueil <paul@...pouillou.net>
> > wrote:
> >>
> >> Register a power supply charger, if the Kconfig option
> >> USB_CONN_GPIO_CHARGER is set, whose online state depends on whether
> >> the USB role is set to device or not.
> >>
> >> This is useful when the USB role is the only way to know if the
> >> device
> >> is charging from USB. The API is the standard power supply charger
> >> API,
> >> you get a /sys/class/power_supply/xxx/online node which tells you
> >> the
> >> state of the charger.
> >>
> >> The sole purpose of this is to give userspace applications a way to
> >> know whether or not the charger is plugged.
> >
> > I'm not sure I understand the purpose of this (third?) way to detect
> > USB charger and notify user space about.
> > Why is extcon not good enough?
>
> We can't have extcon and USB role detection at the same time.
>
> -Paul
>
> >> Signed-off-by: Paul Cercueil <paul@...pouillou.net>
> >> ---
> >> drivers/usb/common/Kconfig | 11 +++++++
> >> drivers/usb/common/usb-conn-gpio.c | 47
> >> ++++++++++++++++++++++++++++++
> >> 2 files changed, 58 insertions(+)
> >>
> >> diff --git a/drivers/usb/common/Kconfig b/drivers/usb/common/Kconfig
> >> index d611477aae41..5405ae96c68f 100644
> >> --- a/drivers/usb/common/Kconfig
> >> +++ b/drivers/usb/common/Kconfig
> >> @@ -49,3 +49,14 @@ config USB_CONN_GPIO
> >>
> >> To compile the driver as a module, choose M here: the
> >> module will
> >> be called usb-conn-gpio.ko
> >> +
> >> +if USB_CONN_GPIO
> >> +
> >> +config USB_CONN_GPIO_CHARGER
> >> + bool "USB charger support"
> >> + select POWER_SUPPLY
> >> + help
> >> + Register a charger with the power supply subsystem. This
> >> will allow
> >> + userspace to know whether or not the device is charging
> >> from USB.
> >> +
> >> +endif
> >> diff --git a/drivers/usb/common/usb-conn-gpio.c
> >> b/drivers/usb/common/usb-conn-gpio.c
> >> index ed204cbb63ea..129d48db280b 100644
> >> --- a/drivers/usb/common/usb-conn-gpio.c
> >> +++ b/drivers/usb/common/usb-conn-gpio.c
> >> @@ -17,6 +17,7 @@
> >> #include <linux/of.h>
> >> #include <linux/pinctrl/consumer.h>
> >> #include <linux/platform_device.h>
> >> +#include <linux/power_supply.h>
> >> #include <linux/regulator/consumer.h>
> >> #include <linux/usb/role.h>
> >>
> >> @@ -38,6 +39,9 @@ struct usb_conn_info {
> >> struct gpio_desc *vbus_gpiod;
> >> int id_irq;
> >> int vbus_irq;
> >> +
> >> + struct power_supply_desc desc;
> >> + struct power_supply *charger;
> >> };
> >>
> >> /**
> >> @@ -98,6 +102,8 @@ static void usb_conn_detect_cable(struct
> >> work_struct *work)
> >> ret = regulator_enable(info->vbus);
> >> if (ret)
> >> dev_err(info->dev, "enable vbus regulator
> >> failed\n");
> >> + } else if (IS_ENABLED(CONFIG_USB_CONN_GPIO_CHARGER)) {
> >> + power_supply_changed(info->charger);
> >> }
> >>
> >> info->last_role = role;
> >> @@ -121,10 +127,35 @@ static irqreturn_t usb_conn_isr(int irq, void
> >> *dev_id)
> >> return IRQ_HANDLED;
> >> }
> >>
> >> +static enum power_supply_property usb_charger_properties[] = {
> >> + POWER_SUPPLY_PROP_ONLINE,
> >> +};
> >> +
> >> +static int usb_charger_get_property(struct power_supply *psy,
> >> + enum power_supply_property psp,
> >> + union power_supply_propval *val)
> >> +{
> >> + struct usb_conn_info *info = power_supply_get_drvdata(psy);
> >> +
> >> + switch (psp) {
> >> + case POWER_SUPPLY_PROP_ONLINE:
> >> + val->intval = info->last_role == USB_ROLE_DEVICE;
What will happen if you not change info->last_role here?
I prefer it's only changed by usb_conn_isr(), if it's changed by other
drivers, for example, through power_supply_get_property(), may skip role
switch.
> >> + break;
> >> + default:
> >> + return -EINVAL;
> >> + }
> >> +
> >> + return 0;
> >> +}
> >> +
> >> static int usb_conn_probe(struct platform_device *pdev)
> >> {
> >> struct device *dev = &pdev->dev;
> >> + struct power_supply_desc *desc;
> >> struct usb_conn_info *info;
> >> + struct power_supply_config cfg = {
> >> + .of_node = dev->of_node,
> >> + };
> >> int ret = 0;
> >>
> >> info = devm_kzalloc(dev, sizeof(*info), GFP_KERNEL);
> >> @@ -203,6 +234,22 @@ static int usb_conn_probe(struct
> >> platform_device *pdev)
> >> }
> >> }
> >>
> >> + if (IS_ENABLED(CONFIG_USB_CONN_GPIO_CHARGER)) {
> >> + desc = &info->desc;
> >> + desc->name = "usb-charger";
> >> + desc->properties = usb_charger_properties;
> >> + desc->num_properties =
> >> ARRAY_SIZE(usb_charger_properties);
> >> + desc->get_property = usb_charger_get_property;
> >> + desc->type = POWER_SUPPLY_TYPE_USB;
> >> + cfg.drv_data = info;
> >> +
> >> + info->charger = devm_power_supply_register(dev,
> >> desc, &cfg);
> >> + if (IS_ERR(info->charger)) {
> >> + dev_err(dev, "Unable to register
> >> charger\n");
> >> + return PTR_ERR(info->charger);
> >> + }
> >> + }
> >> +
> >> platform_set_drvdata(pdev, info);
> >>
> >> /* Perform initial detection */
> >> --
> >> 2.27.0
> >>
> >
> >
> > --
> > With Best Regards,
> > Andy Shevchenko
>
>
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