Re: [RESEND PATCH] usb: common: usb-conn-gpio: Register optional charger
From: Paul Cercueil
Date: Mon Jul 27 2020 - 11:03:15 EST
Le lun. 27 juil. 2020 à 13:42, Chunfeng Yun
<chunfeng.yun@xxxxxxxxxxxx> a écrit :
On Sun, 2020-07-26 at 12:27 +0200, Paul Cercueil wrote:
Le dim. 26 juil. 2020 à 13:14, Andy Shevchenko
<andy.shevchenko@xxxxxxxxx> a écrit :
> On Mon, Jun 22, 2020 at 1:51 AM Paul Cercueil
<paul@xxxxxxxxxxxxxxx>
> 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@xxxxxxxxxxxxxxx>
>> ---
>> 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.
If you read carefully, info->last_role is not modified here :)
-Paul
>> + 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