Hi Baolin,
Some review comments below.
On 10/10/2016 02:22 PM, Baolin Wang wrote:
> This patch introduces the usb charger driver based on usb gadget that
> makes an enhancement to a power driver. It works well in practice but
> that requires a system with suitable hardware.
>
> The basic conception of the usb charger is that, when one usb charger
> is added or removed by reporting from the usb gadget state change or
> the extcon device state change, the usb charger will report to power
> user to set the current limitation.
>
> The usb charger will register notifiees on the usb gadget or the extcon
> device to get notified the usb charger state. It also supplies the
> notification mechanism to userspace When the usb charger state is changed.
>
> Power user will register a notifiee on the usb charger to get notified
> by status changes from the usb charger. It will report to power user
> to set the current limitation when detecting the usb charger is added
> or removed from extcon device state or usb gadget state.
>
> This patch doesn't yet integrate with the gadget code, so some functions
> which rely on the 'gadget' are not completed, that will be implemented
> in the following patches.
>
> Signed-off-by: Baolin Wang <baolin.w...@linaro.org>
> Reviewed-by: Li Jun <jun...@nxp.com>
> Tested-by: Li Jun <jun...@nxp.com>
> ---
> drivers/usb/gadget/Kconfig | 8 +
> drivers/usb/gadget/udc/Makefile | 1 +
> drivers/usb/gadget/udc/charger.c | 785
> ++++++++++++++++++++++++++++++++++++++
> include/linux/usb/charger.h | 186 +++++++++
> include/uapi/linux/usb/charger.h | 31 ++
> 5 files changed, 1011 insertions(+)
> create mode 100644 drivers/usb/gadget/udc/charger.c
> create mode 100644 include/linux/usb/charger.h
> create mode 100644 include/uapi/linux/usb/charger.h
>
> diff --git a/drivers/usb/gadget/Kconfig b/drivers/usb/gadget/Kconfig
> index 2ea3fc3..7520677 100644
> --- a/drivers/usb/gadget/Kconfig
> +++ b/drivers/usb/gadget/Kconfig
> @@ -134,6 +134,14 @@ config U_SERIAL_CONSOLE
> help
> It supports the serial gadget can be used as a console.
>
> +config USB_CHARGER
> + bool "USB charger support"
> + select EXTCON
> + help
> + The usb charger driver based on the usb gadget that makes an
> + enhancement to a power driver which can set the current limitation
> + when the usb charger is added or removed.
> +
> source "drivers/usb/gadget/udc/Kconfig"
>
> #
> diff --git a/drivers/usb/gadget/udc/Makefile b/drivers/usb/gadget/udc/Makefile
> index 98e74ed..ede2351 100644
> --- a/drivers/usb/gadget/udc/Makefile
> +++ b/drivers/usb/gadget/udc/Makefile
> @@ -2,6 +2,7 @@
> CFLAGS_trace.o := -I$(src)
>
> udc-core-y := core.o trace.o
> +udc-core-$(CONFIG_USB_CHARGER) += charger.o
>
> #
> # USB peripheral controller drivers
> diff --git a/drivers/usb/gadget/udc/charger.c
> b/drivers/usb/gadget/udc/charger.c
> new file mode 100644
> index 0000000..16dc477
> --- /dev/null
> +++ b/drivers/usb/gadget/udc/charger.c
> @@ -0,0 +1,785 @@
> +/*
> + * charger.c -- USB charger driver
> + *
> + * Copyright (C) 2016 Linaro Ltd.
> + *
> + * 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.
> + */
> +
> +#include <linux/device.h>
> +#include <linux/err.h>
> +#include <linux/extcon.h>
> +#include <linux/export.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/slab.h>
> +#include <linux/usb.h>
> +#include <linux/usb/ch9.h>
> +#include <linux/usb/gadget.h>
> +#include <linux/usb/charger.h>
> +
> +/* Default current range by charger type. */
> +#define DEFAULT_SDP_CUR_MIN 2
> +#define DEFAULT_SDP_CUR_MAX 500
> +#define DEFAULT_SDP_CUR_MIN_SS 150
> +#define DEFAULT_SDP_CUR_MAX_SS 900
> +#define DEFAULT_DCP_CUR_MIN 500
> +#define DEFAULT_DCP_CUR_MAX 5000
> +#define DEFAULT_CDP_CUR_MIN 1500
> +#define DEFAULT_CDP_CUR_MAX 5000
> +#define DEFAULT_ACA_CUR_MIN 1500
> +#define DEFAULT_ACA_CUR_MAX 5000
> +
> +static DEFINE_IDA(usb_charger_ida);
> +static LIST_HEAD(charger_list);
> +static DEFINE_MUTEX(charger_lock);
> +
> +static struct usb_charger *dev_to_uchger(struct device *dev)
> +{
> + return NULL;
> +}
> +
> +/*
> + * charger_current_show() - Show the charger current.
> + */
> +static ssize_t charger_current_show(struct device *dev,
> + struct device_attribute *attr,
> + char *buf)
> +{
> + struct usb_charger *uchger = dev_to_uchger(dev);
> + unsigned int min, max;
> +
> + usb_charger_get_current(uchger, &min, &max);
> + return sprintf(buf, "%u-%u\n", min, max);
> +}
> +static DEVICE_ATTR_RO(charger_current);
> +
> +/*
> + * charger_type_show() - Show the charger type.
> + *
> + * It can be SDP/DCP/CDP/ACA type, else for unknown type.
> + */
> +static ssize_t charger_type_show(struct device *dev,
> + struct device_attribute *attr,
> + char *buf)
> +{
> + struct usb_charger *uchger = dev_to_uchger(dev);
> + int cnt;
> +
> + switch (uchger->type) {
> + case SDP_TYPE:
> + cnt = sprintf(buf, "%s\n", "SDP");
> + break;
> + case DCP_TYPE:
> + cnt = sprintf(buf, "%s\n", "DCP");
> + break;
> + case CDP_TYPE:
> + cnt = sprintf(buf, "%s\n", "CDP");
> + break;
> + case ACA_TYPE:
> + cnt = sprintf(buf, "%s\n", "ACA");
> + break;
> + default:
> + cnt = sprintf(buf, "%s\n", "UNKNOWN");
> + break;
> + }
> +
> + return cnt;
> +}
> +static DEVICE_ATTR_RO(charger_type);
> +
> +/*
> + * charger_state_show() - Show the charger state.
> + *
> + * Charger state can be present or removed.
> + */
> +static ssize_t charger_state_show(struct device *dev,
> + struct device_attribute *attr,
> + char *buf)
> +{
> + struct usb_charger *uchger = dev_to_uchger(dev);
> + int cnt;
> +
> + switch (uchger->state) {
> + case USB_CHARGER_PRESENT:
> + cnt = sprintf(buf, "%s\n", "PRESENT");
> + break;
> + case USB_CHARGER_REMOVE:
> + cnt = sprintf(buf, "%s\n", "REMOVE");
> + break;
> + default:
> + cnt = sprintf(buf, "%s\n", "UNKNOWN");
> + break;
> + }
> +
> + return cnt;
> +}
> +static DEVICE_ATTR_RO(charger_state);
> +
> +static struct attribute *usb_charger_attrs[] = {
> + &dev_attr_charger_current.attr,
> + &dev_attr_charger_type.attr,
> + &dev_attr_charger_state.attr,
> + NULL
> +};
> +
> +static const struct attribute_group usb_charger_group = {
> + .name = "charger",
> + .attrs = usb_charger_attrs,
> +};
> +__ATTRIBUTE_GROUPS(usb_charger);
> +
> +/*
> + * usb_charger_find_by_name() - Get the usb charger instance by name.
> + * @name - usb charger name.
> + */
> +struct usb_charger *usb_charger_find_by_name(const char *name)
> +{
> + struct usb_charger *uchger;
> +
> + if (WARN(!name, "can't work with NULL name"))
> + return ERR_PTR(-EINVAL);
> +
> + mutex_lock(&charger_lock);
> + list_for_each_entry(uchger, &charger_list, list) {
> + if (!strcmp(uchger->name, name))
> + break;
> + }
> + mutex_unlock(&charger_lock);
> +
> + if (WARN(!uchger, "can't find usb charger"))
> + return ERR_PTR(-ENODEV);
> +
> + return uchger;
> +}
> +EXPORT_SYMBOL_GPL(usb_charger_find_by_name);
> +
> +/*
> + * __usb_charger_get_type() - Get the usb charger type by the callback which
> + * is implemented by users.
> + * @uchger - the usb charger instance.
> + *
> + * Note: This function is just used for getting the charger type, not for
> + * detecting charger type which might affect the DP/DM line when gadget is on
> + * enumeration state.
> + */
> +static enum usb_charger_type __usb_charger_get_type(struct usb_charger
> *uchger)
> +{
> + if (uchger->type != UNKNOWN_TYPE)
> + return uchger->type;
> +
> + if (uchger->get_charger_type)
> + uchger->type = uchger->get_charger_type(uchger);
> + else
> + uchger->type = UNKNOWN_TYPE;
> +
> + return uchger->type;
> +}
> +
> +/*
> + * usb_charger_get_type() - get the usb charger type with lock protection.
> + * @uchger - usb charger instance.
> + *
> + * Users can get the charger type by this safe API, rather than using the
> + * usb_charger structure directly.
> + */
> +enum usb_charger_type usb_charger_get_type(struct usb_charger *uchger)
> +{
> + enum usb_charger_type type;
> +
> + mutex_lock(&uchger->lock);
> + type = __usb_charger_get_type(uchger);
> + mutex_unlock(&uchger->lock);
> +
> + return type;
> +}
> +EXPORT_SYMBOL_GPL(usb_charger_get_type);
> +
> +/*
> + * usb_charger_get_state() - Get the charger state with lock protection.
> + * @uchger - the usb charger instance.
> + *
> + * Users should get the charger state by this safe API.
> + */
> +enum usb_charger_state usb_charger_get_state(struct usb_charger *uchger)
> +{
> + enum usb_charger_state state;
> +
> + mutex_lock(&uchger->lock);
> + state = uchger->state;
> + mutex_unlock(&uchger->lock);
> +
> + return state;
> +}
> +EXPORT_SYMBOL_GPL(usb_charger_get_state);
> +
> +/*
> + * usb_charger_detect_type() - detect the charger type manually.
> + * @uchger - usb charger instance.
> + *
> + * Note: You should ensure you need to detect the charger type manually on
> your
> + * platform.
> + * You should call it at the right gadget state to avoid affecting gadget
> + * enumeration.
> + */
> +int usb_charger_detect_type(struct usb_charger *uchger)
> +{
> + enum usb_charger_type type;
> +
> + if (!uchger->charger_detect)
> + return -EINVAL;
> +
> + type = uchger->charger_detect(uchger);
> +
> + mutex_lock(&uchger->lock);
> + uchger->type = type;
> + mutex_unlock(&uchger->lock);
> +
> + return 0;
> +}
Are there any duplicated code in this function and __usb_charger_get_type()?
> +EXPORT_SYMBOL_GPL(usb_charger_detect_type);
> +
> +/*
> + * usb_charger_notify_work() - Notify users the current has changed by work.
> + * @work - the work instance.
> + *
> + * Note: When users receive the charger present event, they should check the
> + * charger current by usb_charger_get_current() API.
> + */
> +static void usb_charger_notify_work(struct work_struct *work)
> +{
> + struct usb_charger *uchger = work_to_charger(work);
> +
> + mutex_lock(&uchger->lock);
> + if (uchger->state == USB_CHARGER_PRESENT) {
> + raw_notifier_call_chain(&uchger->uchger_nh,
> + USB_CHARGER_PRESENT,
> + uchger);
> + }
> + mutex_unlock(&uchger->lock);
> +}
> +
> +/*
> + * __usb_charger_set_cur_limit_by_type() - Set the current limitation
> + * by charger type.
> + * @uchger - the usb charger instance.
> + * @type - the usb charger type.
> + * @cur_limit - the current limitation.
> + */
> +static int __usb_charger_set_cur_limit_by_type(struct usb_charger *uchger,
> + enum usb_charger_type type,
> + unsigned int cur_limit)
> +{
> + switch (type) {
> + case SDP_TYPE:
> + uchger->cur.sdp_max = (cur_limit > DEFAULT_SDP_CUR_MAX) ?
> + DEFAULT_SDP_CUR_MAX : cur_limit;
> + uchger->sdp_default_cur_change = 1;
> + break;
> + case DCP_TYPE:
> + uchger->cur.dcp_max = (cur_limit > DEFAULT_DCP_CUR_MAX) ?
> + DEFAULT_DCP_CUR_MAX : cur_limit;
> + break;
> + case CDP_TYPE:
> + uchger->cur.cdp_max = (cur_limit > DEFAULT_CDP_CUR_MAX) ?
> + DEFAULT_CDP_CUR_MAX : cur_limit;
> + break;
> + case ACA_TYPE:
> + uchger->cur.aca_max = (cur_limit > DEFAULT_ACA_CUR_MAX) ?
> + DEFAULT_ACA_CUR_MAX : cur_limit;
> + break;
> + default:
> + return -EINVAL;
> + }
> +
> + return 0;
> +}
> +
> +/*
> + * usb_charger_set_cur_limit_by_gadget() - Set the current limitation from
> + * gadget layer.
> + * @gadget - the usb gadget device.
> + * @cur_limit - the current limitation.
> + *
> + * Note: This function is used in atomic contexts without mutex lock.
> + */
> +int usb_charger_set_cur_limit_by_gadget(struct usb_gadget *gadget,
> + unsigned int cur_limit)
> +{
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(usb_charger_set_cur_limit_by_gadget);
> +
> +/*
> + * usb_charger_set_cur_limit_by_type() - Set the current limitation
> + * by charger type with lock protection.
> + * @uchger - the usb charger instance.
> + * @type - the usb charger type.
> + * @cur_limit - the current limitation.
> + *
> + * Users should set the current limitation by this lock protection API.
> + */
> +int usb_charger_set_cur_limit_by_type(struct usb_charger *uchger,
> + enum usb_charger_type type,
> + unsigned int cur_limit)
> +{
> + int ret;
> +
> + if (!uchger)
> + return -EINVAL;
> +
> + mutex_lock(&uchger->lock);
> + ret = __usb_charger_set_cur_limit_by_type(uchger, type, cur_limit);
> + mutex_unlock(&uchger->lock);
> +
> + schedule_work(&uchger->work);
> + return ret;
> +}
> +EXPORT_SYMBOL_GPL(usb_charger_set_cur_limit_by_type);
> +
> +/*
> + * usb_charger_set_current() - Set the usb charger current.
> + * @uchger - the usb charger instance.
> + * @values - the current setting values.
> + */
> +int usb_charger_set_current(struct usb_charger *uchger,
> + struct usb_charger_current *values)
> +{
> + if (!uchger || !values)
> + return -EINVAL;
> +
> + mutex_lock(&uchger->lock);
> + uchger->cur.sdp_min = values->sdp_min;
> + uchger->cur.sdp_max = (values->sdp_max > DEFAULT_SDP_CUR_MAX) ?
> + DEFAULT_SDP_CUR_MAX : values->sdp_max;
> + uchger->cur.dcp_min = values->dcp_min;
> + uchger->cur.dcp_max = (values->dcp_max > DEFAULT_DCP_CUR_MAX) ?
> + DEFAULT_DCP_CUR_MAX : values->dcp_max;
> + uchger->cur.cdp_min = values->cdp_min;
> + uchger->cur.cdp_max = (values->cdp_max > DEFAULT_CDP_CUR_MAX) ?
> + DEFAULT_CDP_CUR_MAX : values->cdp_max;
> + uchger->cur.aca_min = values->aca_min;
> + uchger->cur.aca_max = (values->aca_max > DEFAULT_ACA_CUR_MAX) ?
> + DEFAULT_ACA_CUR_MAX : values->aca_max;
> + uchger->sdp_default_cur_change = 2;
> + mutex_unlock(&uchger->lock);
> +
> + schedule_work(&uchger->work);
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(usb_charger_set_current);
> +
> +/*
> + * usb_charger_get_current() - Get the charger current with lock protection.
> + * @uchger - the usb charger instance.
> + * @min - return the minimum current.
> + * @max - return the maximum current.
> + *
> + * Users should get the charger current by this safe API.
> + */
> +int usb_charger_get_current(struct usb_charger *uchger,
> + unsigned int *min,
> + unsigned int *max)
> +{
> + enum usb_charger_type type;
> +
> + if (!uchger)
> + return -EINVAL;
> +
> + mutex_lock(&uchger->lock);
> + type = __usb_charger_get_type(uchger);
> +
> + switch (type) {
> + case SDP_TYPE:
> + /*
> + * For super speed gadget, the default charger maximum current
> + * should be 900 mA and the default minimum current should be
> + * 150mA.
> + */
> + if (uchger->sdp_default_cur_change != 2 && uchger->gadget &&
> + uchger->gadget->speed >= USB_SPEED_SUPER) {
> + if (!uchger->sdp_default_cur_change)
> + uchger->cur.sdp_max = DEFAULT_SDP_CUR_MAX_SS;
> + uchger->cur.sdp_min = DEFAULT_SDP_CUR_MIN_SS;
> + uchger->sdp_default_cur_change = 2;
> + }
> +
> + *min = uchger->cur.sdp_min;
> + *max = uchger->cur.sdp_max;
> + break;
> + case DCP_TYPE:
> + *min = uchger->cur.dcp_min;
> + *max = uchger->cur.dcp_max;
> + break;
> + case CDP_TYPE:
> + *min = uchger->cur.cdp_min;
> + *max = uchger->cur.cdp_max;
> + break;
> + case ACA_TYPE:
> + *min = uchger->cur.aca_min;
> + *max = uchger->cur.aca_max;
> + break;
> + default:
> + *min = 0;
> + *max = 0;
> + break;
> + }
> + mutex_unlock(&uchger->lock);
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(usb_charger_get_current);
> +
> +/*
> + * usb_charger_register_notify() - Register a notifiee to get notified by
> + * any attach status changes from the usb charger detection.
> + * @uchger - the usb charger instance which is monitored.
> + * @nb - a notifier block to be registered.
> + */
> +int usb_charger_register_notify(struct usb_charger *uchger,
> + struct notifier_block *nb)
> +{
> + int ret;
> +
> + if (!uchger || !nb) {
> + pr_err("Charger or nb can not be NULL.\n");
> + return -EINVAL;
> + }
> +
> + mutex_lock(&uchger->lock);
> + ret = raw_notifier_chain_register(&uchger->uchger_nh, nb);
> + mutex_unlock(&uchger->lock);
> +
> + return ret;
> +}
> +EXPORT_SYMBOL_GPL(usb_charger_register_notify);
> +
> +/*
> + * usb_charger_unregister_notify() - Unregister a notifiee from the usb
> charger.
> + * @uchger - the usb charger instance which is monitored.
> + * @nb - a notifier block to be unregistered.
> + */
> +int usb_charger_unregister_notify(struct usb_charger *uchger,
> + struct notifier_block *nb)
> +{
> + int ret;
> +
> + if (!uchger || !nb) {
> + pr_err("Charger or nb can not be NULL.\n");
> + return -EINVAL;
> + }
> +
> + mutex_lock(&uchger->lock);
> + ret = raw_notifier_chain_unregister(&uchger->uchger_nh, nb);
> + mutex_unlock(&uchger->lock);
> +
> + return ret;
> +}
> +EXPORT_SYMBOL_GPL(usb_charger_unregister_notify);
> +
> +/*
> + * usb_charger_notify_state() - It will notify other device registered
> + * on usb charger when the usb charger state is changed.
> + * @uchger - the usb charger instance.
> + * @state - the state of the usb charger.
> + *
> + * Note: When notify the charger present state to power driver, the power
> driver
> + * should get the current by usb_charger_get_current() API to set current.
> + */
> +static void usb_charger_notify_state(struct usb_charger *uchger,
> + enum usb_charger_state state)
> +{
> + char uchger_state[50] = { 0 };
> + char *envp[] = { uchger_state, NULL };
> +
> + mutex_lock(&uchger->lock);
> + if (uchger->state == state) {
> + mutex_unlock(&uchger->lock);
> + return;
> + }
> +
> + uchger->state = state;
> +
> + switch (state) {
> + case USB_CHARGER_PRESENT:
> + __usb_charger_get_type(uchger);
> + raw_notifier_call_chain(&uchger->uchger_nh,
> + USB_CHARGER_PRESENT,
> + uchger);
> + snprintf(uchger_state, ARRAY_SIZE(uchger_state),
> + "USB_CHARGER_STATE=%s", "USB_CHARGER_PRESENT");
> + break;
> + case USB_CHARGER_REMOVE:
> + uchger->type = UNKNOWN_TYPE;
> + raw_notifier_call_chain(&uchger->uchger_nh,
> + USB_CHARGER_REMOVE,
> + uchger);
> + snprintf(uchger_state, ARRAY_SIZE(uchger_state),
> + "USB_CHARGER_STATE=%s", "USB_CHARGER_REMOVE");
> + break;
> + default:
> + pr_warn("Unknown USB charger state: %d\n", state);
> + mutex_unlock(&uchger->lock);
> + return;
> + }
> +
> + kobject_uevent_env(&uchger->gadget->dev.kobj, KOBJ_CHANGE, envp);
> + mutex_unlock(&uchger->lock);
> +}
> +
> +/*
> + * usb_charger_type_by_extcon() - The notifier call function which is
> registered
> + * on the extcon device.
> + * @nb - the notifier block that notified by extcon device.
> + * @state - the extcon device state.
> + * @data - here specify a extcon device.
> + *
> + * return the notify flag.
> + */
> +static int usb_charger_type_by_extcon(struct notifier_block *nb,
> + unsigned long state, void *data)
> +{
> + struct usb_charger_nb *extcon_nb =
> + container_of(nb, struct usb_charger_nb, nb);
> + struct usb_charger *uchger = extcon_nb->uchger;
> + enum usb_charger_state uchger_state;
> + enum usb_charger_type type;
> +
> + if (WARN(!uchger, "charger can not be NULL"))
> + return NOTIFY_BAD;
> +
> + /* Determine charger type */
> + if (extcon_get_cable_state_(uchger->extcon_dev,
> + EXTCON_CHG_USB_SDP) > 0) {
> + type = SDP_TYPE;
> + uchger_state = USB_CHARGER_PRESENT;
> + } else if (extcon_get_cable_state_(uchger->extcon_dev,
> + EXTCON_CHG_USB_CDP) > 0) {
> + type = CDP_TYPE;
> + uchger_state = USB_CHARGER_PRESENT;
> + } else if (extcon_get_cable_state_(uchger->extcon_dev,
> + EXTCON_CHG_USB_DCP) > 0) {
> + type = DCP_TYPE;
> + uchger_state = USB_CHARGER_PRESENT;
> + } else if (extcon_get_cable_state_(uchger->extcon_dev,
> + EXTCON_CHG_USB_ACA) > 0) {
> + type = ACA_TYPE;
> + uchger_state = USB_CHARGER_PRESENT;
> + } else {
> + type = UNKNOWN_TYPE;
> + uchger_state = USB_CHARGER_REMOVE;
> + }
> +
> + mutex_lock(&uchger->lock);
> + uchger->type = type;
> + mutex_unlock(&uchger->lock);
> +
> + usb_charger_notify_state(uchger, uchger_state);
> +
> + return NOTIFY_OK;
> +}
> +
> +/*
> + * usb_charger_plug_by_extcon() - The notifier call function which is
> registered
> + * on the extcon device.
> + * @nb - the notifier block that notified by extcon device.
> + * @state - the extcon device state.
> + * @data - here specify a extcon device.
> + *
> + * return the notify flag.
> + */
> +static int usb_charger_plug_by_extcon(struct notifier_block *nb,
> + unsigned long state, void *data)
> +{
> + struct usb_charger_nb *extcon_nb =
> + container_of(nb, struct usb_charger_nb, nb);
> + struct usb_charger *uchger = extcon_nb->uchger;
> + enum usb_charger_state uchger_state;
> +
> + if (WARN(!uchger, "charger can not be NULL"))
> + return NOTIFY_BAD;
> +
> + /*
> + * Report event to power users to setting the current limitation
> + * for this usb charger when one usb charger is added or removed
> + * with detecting by extcon device.
> + */
> + if (state)
> + uchger_state = USB_CHARGER_PRESENT;
> + else
> + uchger_state = USB_CHARGER_REMOVE;
> +
> + usb_charger_notify_state(uchger, uchger_state);
> +
> + return NOTIFY_OK;
> +}
> +
> +/*
> + * usb_charger_plug_by_gadget() - Set the usb charger current limitation
> + * according to the usb gadget device state.
> + * @gadget - the usb gadget device.
> + * @state - the usb gadget state.
> + */
> +int usb_charger_plug_by_gadget(struct usb_gadget *gadget,
> + unsigned long state)
> +{
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(usb_charger_plug_by_gadget);
> +
> +/*
> + * usb_charger_register() - Register a new usb charger.
> + * @uchger - the new usb charger instance.
> + */
Where is usb_charger_unregister()?
> +static int usb_charger_register(struct usb_charger *uchger)
> +{
> + int ret;
> +
> + ret = ida_simple_get(&usb_charger_ida, 0, 0, GFP_KERNEL);
> + if (ret < 0) {
> + pr_err("Failed to register usb charger: %d\n", ret);
> + return ret;
> + }
> +
> + uchger->id = ret;
> + scnprintf(uchger->name, CHARGER_NAME_MAX, "usb-charger.%d", uchger->id);
> +
> + ret = sysfs_create_groups(&uchger->gadget->dev.kobj,
> + usb_charger_groups);
> + if (ret) {
> + pr_err("Failed to create usb charger attributes: %d\n", ret);
> + goto fail;
> + }
> +
> + mutex_lock(&charger_lock);
> + list_add_tail(&uchger->list, &charger_list);
> + mutex_unlock(&charger_lock);
> +
> + return 0;
> +
> +fail:
> + ida_simple_remove(&usb_charger_ida, uchger->id);
> + uchger->id = -1;
> + return ret;
You only have one point to goto here. Why not just move this code block
to above goto place?
> +}
> +
> +int usb_charger_init(struct usb_gadget *ugadget)
> +{
> + struct usb_charger *uchger;
> + struct extcon_dev *edev;
> + int ret;
> +
> + uchger = kzalloc(sizeof(struct usb_charger), GFP_KERNEL);
Memory leak. I didn't find kfree() in usb_charger_exit().
> + if (!uchger)
> + return -ENOMEM;
> +
> + uchger->type = UNKNOWN_TYPE;
> + uchger->state = USB_CHARGER_DEFAULT;
> + uchger->id = -1;
> + uchger->sdp_default_cur_change = 0;
> +
> + uchger->cur.sdp_min = DEFAULT_SDP_CUR_MIN;
> + uchger->cur.sdp_max = DEFAULT_SDP_CUR_MAX;
> + uchger->cur.dcp_min = DEFAULT_DCP_CUR_MIN;
> + uchger->cur.dcp_max = DEFAULT_DCP_CUR_MAX;
> + uchger->cur.cdp_min = DEFAULT_CDP_CUR_MIN;
> + uchger->cur.cdp_max = DEFAULT_CDP_CUR_MAX;
> + uchger->cur.aca_min = DEFAULT_ACA_CUR_MIN;
> + uchger->cur.aca_max = DEFAULT_ACA_CUR_MAX;
> +
> + mutex_init(&uchger->lock);
> + RAW_INIT_NOTIFIER_HEAD(&uchger->uchger_nh);
> + INIT_WORK(&uchger->work, usb_charger_notify_work);
> +
> + /* Register a notifier on a extcon device if it is exsited */
> + edev = extcon_get_edev_by_phandle(ugadget->dev.parent, 0);
> + if (!IS_ERR_OR_NULL(edev)) {
> + uchger->extcon_dev = edev;
> + uchger->extcon_nb.nb.notifier_call = usb_charger_plug_by_extcon;
> + uchger->extcon_nb.uchger = uchger;
> + ret = extcon_register_notifier(edev, EXTCON_USB,
> + &uchger->extcon_nb.nb);
> + if (ret) {
> + pr_err("Failed to register extcon USB notifier.\n");
> + goto fail_extcon;
> + }
> +
> + uchger->extcon_type_nb.nb.notifier_call =
> + usb_charger_type_by_extcon;
> + uchger->extcon_type_nb.uchger = uchger;
> +
> + ret = extcon_register_notifier(edev, EXTCON_CHG_USB_SDP,
> + &uchger->extcon_type_nb.nb);
> + if (ret) {
> + pr_err("Failed to register extcon USB SDP notifier.\n");
> + goto fail_extcon_sdp;
> + }
> +
> + ret = extcon_register_notifier(edev, EXTCON_CHG_USB_CDP,
> + &uchger->extcon_type_nb.nb);
> + if (ret) {
> + pr_err("Failed to register extcon USB CDP notifier.\n");
> + goto fail_extcon_cdp;
> + }
> +
> + ret = extcon_register_notifier(edev, EXTCON_CHG_USB_DCP,
> + &uchger->extcon_type_nb.nb);
> + if (ret) {
> + pr_err("Failed to register extcon USB DCP notifier.\n");
> + goto fail_extcon_dcp;
> + }
> +
> + ret = extcon_register_notifier(edev, EXTCON_CHG_USB_ACA,
> + &uchger->extcon_type_nb.nb);
> + if (ret) {
> + pr_err("Failed to register extcon USB ACA notifier.\n");
> + goto fail_extcon_aca;
> + }
> + }
> +
> + uchger->gadget = ugadget;
> + uchger->old_gadget_state = USB_STATE_NOTATTACHED;
> +
> + /* Register a new usb charger */
> + ret = usb_charger_register(uchger);
> + if (ret)
> + goto fail_register;
> +
> + return 0;
> +
> +fail_register:
> + extcon_unregister_notifier(uchger->extcon_dev,
> + EXTCON_CHG_USB_ACA,
> + &uchger->extcon_type_nb.nb);
> +fail_extcon_aca:
> + extcon_unregister_notifier(uchger->extcon_dev,
> + EXTCON_CHG_USB_DCP,
> + &uchger->extcon_type_nb.nb);
> +fail_extcon_dcp:
> + extcon_unregister_notifier(uchger->extcon_dev,
> + EXTCON_CHG_USB_CDP,
> + &uchger->extcon_type_nb.nb);
> +fail_extcon_cdp:
> + extcon_unregister_notifier(uchger->extcon_dev,
> + EXTCON_CHG_USB_SDP,
> + &uchger->extcon_type_nb.nb);
> +fail_extcon_sdp:
> + extcon_unregister_notifier(uchger->extcon_dev,
> + EXTCON_USB,
> + &uchger->extcon_nb.nb);
> +fail_extcon:
> + kfree(uchger);
> +
> + return ret;
> +}
> +
> +int usb_charger_exit(struct usb_gadget *ugadget)
> +{
> + return 0;
> +}
> +
> +MODULE_AUTHOR("Baolin Wang <baolin.w...@linaro.org>");
> +MODULE_DESCRIPTION("USB charger driver");
> +MODULE_LICENSE("GPL v2");
> diff --git a/include/linux/usb/charger.h b/include/linux/usb/charger.h
> new file mode 100644
> index 0000000..7819eac
> --- /dev/null
> +++ b/include/linux/usb/charger.h
> @@ -0,0 +1,186 @@
> +#ifndef __LINUX_USB_CHARGER_H__
> +#define __LINUX_USB_CHARGER_H__
> +
> +#include <uapi/linux/usb/ch9.h>
> +#include <uapi/linux/usb/charger.h>
> +
> +#define CHARGER_NAME_MAX 30
> +#define work_to_charger(w) (container_of((w), struct usb_charger, work))
> +
> +/* Current range by charger type */
> +struct usb_charger_current {
> + unsigned int sdp_min;
> + unsigned int sdp_max;
> + unsigned int dcp_min;
> + unsigned int dcp_max;
> + unsigned int cdp_min;
> + unsigned int cdp_max;
> + unsigned int aca_min;
> + unsigned int aca_max;
> +};
> +
> +struct usb_charger_nb {
> + struct notifier_block nb;
> + struct usb_charger *uchger;
> +};
> +
> +/**
> + * struct usb_charger - describe one usb charger
> + * @name: Charger name.
> + * @list: For linking usb charger instances into one global list.
> + * @uchger_nh: Notifier head for users to register.
> + * @lock: Protect the notifier head and charger.
> + * @id: The charger id.
> + * @type: The charger type, it can be SDP_TYPE, DCP_TYPE, CDP_TYPE or
> + * ACA_TYPE.
> + * @state: Indicate the charger state.
> + * @cur: Describe the current range by charger type.
> + * @work: Workqueue to be used for reporting users current has changed.
> + * @extcon_dev: For supporting extcon usb gpio device to detect usb cable
> + * event (plugin or not).
> + * @extcon_nb: Report the events to charger from extcon device.
> + * @extcon_type_nb: Report the charger type from extcon device.
> + * @gadget: One usb charger is always tied to one usb gadget.
> + * @old_gadget_state: Record the previous state of one usb gadget to check if
> + * the gadget state is changed. If gadget state is changed, then notify the
> + * event to charger.
> + * @sdp_default_cur_change: Check if it is needed to change the SDP charger
> + * default maximum current.
> + * @get_charger_type: User can get charger type by implementing this
> callback.
> + * @charger_detect: Charger detection method can be implemented if you need
> to
> + * manually detect the charger type.
> + *
> + * Users can set 'get_charger_type' and 'charger_detect' callbacks directly
> + * according to their own requirements. Beyond that, users can not touch
> + * anything else directly in this structure.
> + */
> +struct usb_charger {
> + char name[CHARGER_NAME_MAX];
> + struct list_head list;
> + struct raw_notifier_head uchger_nh;
> + struct mutex lock;
Needs comments for lock.
> + int id;
> + enum usb_charger_type type;
> + enum usb_charger_state state;
> + struct usb_charger_current cur;
> + struct work_struct work;
> +
> + struct extcon_dev *extcon_dev;
> + struct usb_charger_nb extcon_nb;
> + struct usb_charger_nb extcon_type_nb;
> +
> + struct usb_gadget *gadget;
> + enum usb_device_state old_gadget_state;
> + unsigned int sdp_default_cur_change;
> +
> + enum usb_charger_type (*get_charger_type)(struct usb_charger *);
> + enum usb_charger_type (*charger_detect)(struct usb_charger *);
> +};
> +
> +#ifdef CONFIG_USB_CHARGER
> +extern struct usb_charger *usb_charger_find_by_name(const char *name);
> +
> +extern int usb_charger_register_notify(struct usb_charger *uchger,
> + struct notifier_block *nb);
> +extern int usb_charger_unregister_notify(struct usb_charger *uchger,
> + struct notifier_block *nb);
> +
> +extern int usb_charger_set_current(struct usb_charger *uchger,
> + struct usb_charger_current *values);
> +extern int usb_charger_get_current(struct usb_charger *uchger,
> + unsigned int *min, unsigned int *max);
> +
> +extern int usb_charger_set_cur_limit_by_type(struct usb_charger *uchger,
> + enum usb_charger_type type,
> + unsigned int cur_limit);
> +extern int usb_charger_set_cur_limit_by_gadget(struct usb_gadget *gadget,
> + unsigned int cur_limit);
> +
> +extern int usb_charger_plug_by_gadget(struct usb_gadget *gadget,
> + unsigned long state);
> +extern enum usb_charger_type usb_charger_get_type(struct usb_charger
> *uchger);
> +extern int usb_charger_detect_type(struct usb_charger *uchger);
> +extern enum usb_charger_state usb_charger_get_state(struct usb_charger
> *uchger);
> +
> +extern int usb_charger_init(struct usb_gadget *ugadget);
> +extern int usb_charger_exit(struct usb_gadget *ugadget);
You don't need to put "extern" here.
Please use "scripts/checkpatch.pl --strict" to check this.
> +#else
> +static inline struct usb_charger *usb_charger_find_by_name(const char *name)
> +{
> + return ERR_PTR(-ENODEV);
> +}
> +
> +static inline int usb_charger_register_notify(struct usb_charger *uchger,
> + struct notifier_block *nb)
> +{
> + return 0;
> +}
> +
> +static inline int usb_charger_unregister_notify(struct usb_charger *uchger,
> + struct notifier_block *nb)
> +{
> + return 0;
> +}
> +
> +static inline int usb_charger_set_current(struct usb_charger *uchger,
> + struct usb_charger_current *values)
> +{
> + return 0;
> +}
> +
> +static inline int usb_charger_get_current(struct usb_charger *uchger,
> + unsigned int *min, unsigned int *max)
> +{
> + return 0;
> +}
> +
> +static inline int
> +usb_charger_set_cur_limit_by_type(struct usb_charger *uchger,
> + enum usb_charger_type type,
> + unsigned int cur_limit)
> +{
> + return 0;
> +}
> +
> +static inline int
> +usb_charger_set_cur_limit_by_gadget(struct usb_gadget *gadget,
> + unsigned int cur_limit)
> +{
> + return 0;
> +}
> +
> +static inline enum usb_charger_type
> +usb_charger_get_type(struct usb_charger *uchger)
> +{
> + return UNKNOWN_TYPE;
> +}
> +
> +static inline enum usb_charger_state
> +usb_charger_get_state(struct usb_charger *uchger)
> +{
> + return USB_CHARGER_REMOVE;
> +}
> +
> +static inline int usb_charger_detect_type(struct usb_charger *uchger)
> +{
> + return 0;
> +}
> +
> +static inline int usb_charger_plug_by_gadget(struct usb_gadget *gadget,
> + unsigned long state)
> +{
> + return 0;
> +}
> +
> +static inline int usb_charger_init(struct usb_gadget *ugadget)
> +{
> + return 0;
> +}
> +
> +static inline int usb_charger_exit(struct usb_gadget *ugadget)
> +{
> + return 0;
> +}
> +#endif
> +
> +#endif /* __LINUX_USB_CHARGER_H__ */
> diff --git a/include/uapi/linux/usb/charger.h
> b/include/uapi/linux/usb/charger.h
> new file mode 100644
> index 0000000..3c56ec4
> --- /dev/null
> +++ b/include/uapi/linux/usb/charger.h
> @@ -0,0 +1,31 @@
> +/*
> + * This file defines the USB charger type and state that are needed for
> + * USB device APIs.
> + */
> +
> +#ifndef _UAPI__LINUX_USB_CHARGER_H
> +#define _UAPI__LINUX_USB_CHARGER_H
> +
> +/*
> + * USB charger type:
> + * SDP (Standard Downstream Port)
> + * DCP (Dedicated Charging Port)
> + * CDP (Charging Downstream Port)
> + * ACA (Accessory Charger Adapters)
> + */
> +enum usb_charger_type {
> + UNKNOWN_TYPE,
> + SDP_TYPE,
> + DCP_TYPE,
> + CDP_TYPE,
> + ACA_TYPE,
> +};
> +
> +/* USB charger state */
> +enum usb_charger_state {
> + USB_CHARGER_DEFAULT,
> + USB_CHARGER_PRESENT,
> + USB_CHARGER_REMOVE,
> +};
> +
> +#endif /* _UAPI__LINUX_USB_CHARGER_H */
Best regards,
Lu Baolu
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