[PATCH v3 0/3] Introduce USB charger support in USB phy

[PATCH v3 0/3] Introduce USB charger support in USB phy

[Baolin Wang]

Currently the Linux kernel does not provide any standard integration of this
feature that integrates the USB subsystem with the system power regulation
provided by PMICs meaning that either vendors must add this in their kernels
or USB gadget devices based on Linux (such as mobile phones) may not behave
as they should. Thus provide a standard USB charger support in USB phy core
for doing this in kernel.

Now introduce one user with wm831x_power to support and test the usb charger.
In future we will also cnvert below power drivers:
drivers/power/supply/axp288_charger.c
drivers/power/supply/bq24190_charger.c
drivers/power/supply/charger-manager.c
drivers/power/supply/qcom_smbb.c

Changes since v1:
 - Fix building errors.
Changes since v2:
 - Add DT binding documentation for wm831x_power driver.
 - Change 'usb-phy' as one optional property for wm831x_power driver.

Baolin Wang (3):
  include: uapi: usb: Introduce USB charger type and state definition
  usb: phy: Add USB charger support
  power: wm831x_power: Support USB charger current limit management

 Documentation/devicetree/bindings/mfd/wm831x.txt |    1 +
 drivers/power/supply/wm831x_power.c              |   58 +++++
 drivers/usb/phy/phy.c                            |  272 ++++++++++++++++++++++
 include/linux/usb/phy.h                          |   49 ++++
 include/uapi/linux/usb/charger.h                 |   31 +++
 5 files changed, 411 insertions(+)
 create mode 100644 include/uapi/linux/usb/charger.h

-- 
1.7.9.5

[PATCH v3 1/3] include: uapi: usb: Introduce USB charger type and state definition

[Baolin Wang]

Introducing USB charger type and state definition can help
to support USB charging which will be added in USB phy core.

Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
---
 include/uapi/linux/usb/charger.h |   31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)
 create mode 100644 include/uapi/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..5f72af3
--- /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_ABSENT,
+};
+
+#endif /* _UAPI__LINUX_USB_CHARGER_H */
-- 
1.7.9.5

[PATCH v3 2/3] usb: phy: Add USB charger support

[Baolin Wang]

This patch introduces the usb charger support based on usb phy that
makes an enhancement to a power driver. The basic conception of the
usb charger is that, when one usb charger is added or removed by
reporting from the extcon device state change, the usb charger will
report to power user to set the current limitation.

Power user can register a notifiee on the usb phy by issuing
usb_register_notifier() to get notified by charger status changes
or charger current changes.

we can notify what current to be drawn to power user according to
different charger type, and now we have 2 methods to get charger type.
One is get charger type from extcon subsystem, which also means the
charger state changes. Another is we can get the charger type from
USB controller detecting or PMIC detecting, and the charger state
changes should be told by issuing usb_phy_set_charger_state().

Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
---
 drivers/usb/phy/phy.c   |  272 +++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/usb/phy.h |   49 +++++++++
 2 files changed, 321 insertions(+)

diff --git a/drivers/usb/phy/phy.c b/drivers/usb/phy/phy.c
index 032f5af..2dc48bb 100644
--- a/drivers/usb/phy/phy.c
+++ b/drivers/usb/phy/phy.c
@@ -18,6 +18,18 @@
 
 #include <linux/usb/phy.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 LIST_HEAD(phy_list);
 static LIST_HEAD(phy_bind_list);
 static DEFINE_SPINLOCK(phy_lock);
@@ -77,6 +89,221 @@ static struct usb_phy *__of_usb_find_phy(struct device_node *node)
 	return ERR_PTR(-EPROBE_DEFER);
 }
 
+static void usb_phy_set_default_current(struct usb_phy *usb_phy)
+{
+	usb_phy->chg_cur.sdp_min = DEFAULT_SDP_CUR_MIN;
+	usb_phy->chg_cur.sdp_max = DEFAULT_SDP_CUR_MAX;
+	usb_phy->chg_cur.dcp_min = DEFAULT_DCP_CUR_MIN;
+	usb_phy->chg_cur.dcp_max = DEFAULT_DCP_CUR_MAX;
+	usb_phy->chg_cur.cdp_min = DEFAULT_CDP_CUR_MIN;
+	usb_phy->chg_cur.cdp_max = DEFAULT_CDP_CUR_MAX;
+	usb_phy->chg_cur.aca_min = DEFAULT_ACA_CUR_MIN;
+	usb_phy->chg_cur.aca_max = DEFAULT_ACA_CUR_MAX;
+}
+
+/**
+ * usb_phy_notify_charger_work - notify the USB charger state
+ * @work - the charger work to notify the USB charger state
+ *
+ * This work can be issued when USB charger state has been changed or
+ * USB charger current has been changed, then we can notify the current
+ * what can be drawn to power user and the charger state to userspace.
+ *
+ * If we get the charger type from extcon subsystem, we can notify the
+ * charger state to power user automatically by usb_phy_get_charger_type()
+ * issuing from extcon subsystem.
+ *
+ * If we get the charger type from ->charger_detect() instead of extcon
+ * subsystem, the usb phy driver should issue usb_phy_set_charger_state()
+ * to set charger state when the charger state has been changed.
+ */
+static void usb_phy_notify_charger_work(struct work_struct *work)
+{
+	struct usb_phy *usb_phy = container_of(work, struct usb_phy, chg_work);
+	char uchger_state[50] = { 0 };
+	char *envp[] = { uchger_state, NULL };
+	unsigned int min, max;
+
+	switch (usb_phy->chg_state) {
+	case USB_CHARGER_PRESENT:
+		usb_phy_get_charger_current(usb_phy, &min, &max);
+
+		atomic_notifier_call_chain(&usb_phy->notifier, max, usb_phy);
+		snprintf(uchger_state, ARRAY_SIZE(uchger_state),
+			 "USB_CHARGER_STATE=%s", "USB_CHARGER_PRESENT");
+		break;
+	case USB_CHARGER_ABSENT:
+		usb_phy_set_default_current(usb_phy);
+
+		atomic_notifier_call_chain(&usb_phy->notifier, 0, usb_phy);
+		snprintf(uchger_state, ARRAY_SIZE(uchger_state),
+			 "USB_CHARGER_STATE=%s", "USB_CHARGER_ABSENT");
+		break;
+	default:
+		dev_warn(usb_phy->dev, "Unknown USB charger state: %d\n",
+			 usb_phy->chg_state);
+		return;
+	}
+
+	kobject_uevent_env(&usb_phy->dev->kobj, KOBJ_CHANGE, envp);
+}
+
+static void __usb_phy_get_charger_type(struct usb_phy *usb_phy)
+{
+	if (extcon_get_state(usb_phy->edev, EXTCON_CHG_USB_SDP) > 0) {
+		usb_phy->chg_type = SDP_TYPE;
+		usb_phy->chg_state = USB_CHARGER_PRESENT;
+	} else if (extcon_get_state(usb_phy->edev, EXTCON_CHG_USB_CDP) > 0) {
+		usb_phy->chg_type = CDP_TYPE;
+		usb_phy->chg_state = USB_CHARGER_PRESENT;
+	} else if (extcon_get_state(usb_phy->edev, EXTCON_CHG_USB_DCP) > 0) {
+		usb_phy->chg_type = DCP_TYPE;
+		usb_phy->chg_state = USB_CHARGER_PRESENT;
+	} else if (extcon_get_state(usb_phy->edev, EXTCON_CHG_USB_ACA) > 0) {
+		usb_phy->chg_type = ACA_TYPE;
+		usb_phy->chg_state = USB_CHARGER_PRESENT;
+	} else {
+		usb_phy->chg_type = UNKNOWN_TYPE;
+		usb_phy->chg_state = USB_CHARGER_ABSENT;
+	}
+
+	schedule_work(&usb_phy->chg_work);
+}
+
+/**
+ * usb_phy_get_charger_type - get charger type from extcon subsystem
+ * @nb -the notifier block to determine charger type
+ * @state - the cable state
+ * @data - private data
+ *
+ * Determin the charger type from extcon subsystem which also means the
+ * charger state has been chaned, then we should notify this event.
+ */
+static int usb_phy_get_charger_type(struct notifier_block *nb,
+				    unsigned long state, void *data)
+{
+	struct usb_phy *usb_phy = container_of(nb, struct usb_phy, type_nb);
+
+	__usb_phy_get_charger_type(usb_phy);
+	return NOTIFY_OK;
+}
+
+/**
+ * usb_phy_set_charger_current - set the USB charger current
+ * @usb_phy - the USB phy to be used
+ * @mA - the current need to be set
+ *
+ * Usually we only change the charger default current when USB finished the
+ * enumeration as one SDP charger. As one SDP charger, usb_phy_set_power()
+ * will issue this function to change charger current when after setting USB
+ * configuration, or suspend/resume USB. For other type charger, we should
+ * use the default charger current and we do not suggest to issue this function
+ * to change the charger current.
+ *
+ * When USB charger current has been changed, we need to notify the power users.
+ */
+void usb_phy_set_charger_current(struct usb_phy *usb_phy, unsigned int mA)
+{
+	switch (usb_phy->chg_type) {
+	case SDP_TYPE:
+		if (usb_phy->chg_cur.sdp_max == mA)
+			return;
+
+		usb_phy->chg_cur.sdp_max = (mA > DEFAULT_SDP_CUR_MAX_SS) ?
+			DEFAULT_SDP_CUR_MAX_SS : mA;
+		break;
+	case DCP_TYPE:
+		if (usb_phy->chg_cur.dcp_max == mA)
+			return;
+
+		usb_phy->chg_cur.dcp_max = (mA > DEFAULT_DCP_CUR_MAX) ?
+			DEFAULT_DCP_CUR_MAX : mA;
+		break;
+	case CDP_TYPE:
+		if (usb_phy->chg_cur.cdp_max == mA)
+			return;
+
+		usb_phy->chg_cur.cdp_max = (mA > DEFAULT_CDP_CUR_MAX) ?
+			DEFAULT_CDP_CUR_MAX : mA;
+		break;
+	case ACA_TYPE:
+		if (usb_phy->chg_cur.aca_max == mA)
+			return;
+
+		usb_phy->chg_cur.aca_max = (mA > DEFAULT_ACA_CUR_MAX) ?
+			DEFAULT_ACA_CUR_MAX : mA;
+		break;
+	default:
+		return;
+	}
+
+	schedule_work(&usb_phy->chg_work);
+}
+EXPORT_SYMBOL_GPL(usb_phy_set_charger_current);
+
+/**
+ * usb_phy_get_charger_current - get the USB charger current
+ * @usb_phy - the USB phy to be used
+ * @min - the minimum current
+ * @max - the maximum current
+ *
+ * Usually we will notify the maximum current to power user, but for some
+ * special case, power user also need the minimum current value. Then the
+ * power user can issue this function to get the suitable current.
+ */
+void usb_phy_get_charger_current(struct usb_phy *usb_phy,
+				 unsigned int *min, unsigned int *max)
+{
+	switch (usb_phy->chg_type) {
+	case SDP_TYPE:
+		*min = usb_phy->chg_cur.sdp_min;
+		*max = usb_phy->chg_cur.sdp_max;
+		break;
+	case DCP_TYPE:
+		*min = usb_phy->chg_cur.dcp_min;
+		*max = usb_phy->chg_cur.dcp_max;
+		break;
+	case CDP_TYPE:
+		*min = usb_phy->chg_cur.cdp_min;
+		*max = usb_phy->chg_cur.cdp_max;
+		break;
+	case ACA_TYPE:
+		*min = usb_phy->chg_cur.aca_min;
+		*max = usb_phy->chg_cur.aca_max;
+		break;
+	default:
+		*min = 0;
+		*max = 0;
+		break;
+	}
+}
+EXPORT_SYMBOL_GPL(usb_phy_get_charger_current);
+
+/**
+ * usb_phy_set_charger_state - set the USB charger state
+ * @usb_phy - the USB phy to be used
+ * @state - the new state need to be set for charger
+ *
+ * The usb phy driver can issue this function when the usb phy driver
+ * detected the charger state has been changed, in this case the charger
+ * type should be get from ->charger_detect().
+ */
+void usb_phy_set_charger_state(struct usb_phy *usb_phy,
+			       enum usb_charger_state state)
+{
+	if (usb_phy->chg_state == state || !usb_phy->charger_detect)
+		return;
+
+	usb_phy->chg_state = state;
+	if (usb_phy->chg_state == USB_CHARGER_PRESENT)
+		usb_phy->chg_type = usb_phy->charger_detect(usb_phy);
+	else
+		usb_phy->chg_type = UNKNOWN_TYPE;
+
+	schedule_work(&usb_phy->chg_work);
+}
+EXPORT_SYMBOL_GPL(usb_phy_set_charger_state);
+
 static void devm_usb_phy_release(struct device *dev, void *res)
 {
 	struct usb_phy *phy = *(struct usb_phy **)res;
@@ -124,6 +351,44 @@ static int usb_add_extcon(struct usb_phy *x)
 					"register VBUS notifier failed\n");
 				return ret;
 			}
+		} else {
+			x->type_nb.notifier_call = usb_phy_get_charger_type;
+
+			ret = devm_extcon_register_notifier(x->dev, x->edev,
+							    EXTCON_CHG_USB_SDP,
+							    &x->type_nb);
+			if (ret) {
+				dev_err(x->dev,
+					"register extcon USB SDP failed.\n");
+				return ret;
+			}
+
+			ret = devm_extcon_register_notifier(x->dev, x->edev,
+							    EXTCON_CHG_USB_CDP,
+							    &x->type_nb);
+			if (ret) {
+				dev_err(x->dev,
+					"register extcon USB CDP failed.\n");
+				return ret;
+			}
+
+			ret = devm_extcon_register_notifier(x->dev, x->edev,
+							    EXTCON_CHG_USB_DCP,
+							    &x->type_nb);
+			if (ret) {
+				dev_err(x->dev,
+					"register extcon USB DCP failed.\n");
+				return ret;
+			}
+
+			ret = devm_extcon_register_notifier(x->dev, x->edev,
+							    EXTCON_CHG_USB_ACA,
+							    &x->type_nb);
+			if (ret) {
+				dev_err(x->dev,
+					"register extcon USB ACA failed.\n");
+				return ret;
+			}
 		}
 
 		if (x->id_nb.notifier_call) {
@@ -145,6 +410,13 @@ static int usb_add_extcon(struct usb_phy *x)
 		}
 	}
 
+	usb_phy_set_default_current(x);
+	INIT_WORK(&x->chg_work, usb_phy_notify_charger_work);
+	x->chg_type = UNKNOWN_TYPE;
+	x->chg_state = USB_CHARGER_DEFAULT;
+	if (x->type_nb.notifier_call)
+		__usb_phy_get_charger_type(x);
+
 	return 0;
 }
 
diff --git a/include/linux/usb/phy.h b/include/linux/usb/phy.h
index 2992451..de881b1 100644
--- a/include/linux/usb/phy.h
+++ b/include/linux/usb/phy.h
@@ -12,6 +12,7 @@
 #include <linux/extcon.h>
 #include <linux/notifier.h>
 #include <linux/usb.h>
+#include <uapi/linux/usb/charger.h>
 
 enum usb_phy_interface {
 	USBPHY_INTERFACE_MODE_UNKNOWN,
@@ -72,6 +73,17 @@ struct usb_phy_io_ops {
 	int (*write)(struct usb_phy *x, u32 val, u32 reg);
 };
 
+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_phy {
 	struct device		*dev;
 	const char		*label;
@@ -91,6 +103,13 @@ struct usb_phy {
 	struct extcon_dev	*id_edev;
 	struct notifier_block	vbus_nb;
 	struct notifier_block	id_nb;
+	struct notifier_block	type_nb;
+
+	/* Support USB charger */
+	enum usb_charger_type	chg_type;
+	enum usb_charger_state	chg_state;
+	struct usb_charger_current	chg_cur;
+	struct work_struct		chg_work;
 
 	/* for notification of usb_phy_events */
 	struct atomic_notifier_head	notifier;
@@ -129,6 +148,12 @@ struct usb_phy {
 			enum usb_device_speed speed);
 	int	(*notify_disconnect)(struct usb_phy *x,
 			enum usb_device_speed speed);
+
+	/*
+	 * Charger detection method can be implemented if you need to
+	 * manually detect the charger type.
+	 */
+	enum usb_charger_type (*charger_detect)(struct usb_phy *x);
 };
 
 /**
@@ -219,6 +244,12 @@ extern struct usb_phy *devm_usb_get_phy_by_node(struct device *dev,
 extern int usb_bind_phy(const char *dev_name, u8 index,
 				const char *phy_dev_name);
 extern void usb_phy_set_event(struct usb_phy *x, unsigned long event);
+extern void usb_phy_set_charger_current(struct usb_phy *usb_phy,
+					unsigned int mA);
+extern void usb_phy_get_charger_current(struct usb_phy *usb_phy,
+					unsigned int *min, unsigned int *max);
+extern void usb_phy_set_charger_state(struct usb_phy *usb_phy,
+				      enum usb_charger_state state);
 #else
 static inline struct usb_phy *usb_get_phy(enum usb_phy_type type)
 {
@@ -270,11 +301,29 @@ static inline int usb_bind_phy(const char *dev_name, u8 index,
 static inline void usb_phy_set_event(struct usb_phy *x, unsigned long event)
 {
 }
+
+static inline void usb_phy_set_charger_current(struct usb_phy *usb_phy,
+					       unsigned int mA)
+{
+}
+
+static inline void usb_phy_get_charger_current(struct usb_phy *usb_phy,
+					       unsigned int *min,
+					       unsigned int *max)
+{
+}
+
+static inline void usb_phy_set_charger_state(struct usb_phy *usb_phy,
+					     enum usb_charger_state state)
+{
+}
 #endif
 
 static inline int
 usb_phy_set_power(struct usb_phy *x, unsigned mA)
 {
+	usb_phy_set_charger_current(x, mA);
+
 	if (x && x->set_power)
 		return x->set_power(x, mA);
 	return 0;
-- 
1.7.9.5

Re: [PATCH v3 2/3] usb: phy: Add USB charger support

[Manu Gautam]

Hi,


On 7/25/2017 1:30 PM, Baolin Wang wrote:
> This patch introduces the usb charger support based on usb phy that
> makes an enhancement to a power driver. The basic conception of the
> usb charger is that, when one usb charger is added or removed by
> reporting from the extcon device state change, the usb charger will
> report to power user to set the current limitation.
>
> Power user can register a notifiee on the usb phy by issuing
> usb_register_notifier() to get notified by charger status changes
> or charger current changes.

Why can't we use power_supply framework for this?
Power user can register usb power_supply and USB PHY driver
can update charging current using - power_supply_set_property().



> we can notify what current to be drawn to power user according to
> different charger type, and now we have 2 methods to get charger type.
> One is get charger type from extcon subsystem, which also means the
> charger state changes. Another is we can get the charger type from
> USB controller detecting or PMIC detecting, and the charger state
> changes should be told by issuing usb_phy_set_charger_state().
>
> Signed-off-by: Baolin Wang <baolin.wang-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
> ---
>  drivers/usb/phy/phy.c   |  272 +++++++++++++++++++++++++++++++++++++++++++++++
>  include/linux/usb/phy.h |   49 +++++++++

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Re: [PATCH v3 2/3] usb: phy: Add USB charger support

[Baolin Wang]

Hi Manu,

On 25 July 2017 at 19:19, Manu Gautam <mgautam@codeaurora.org> wrote:
> Hi,
>
>
> On 7/25/2017 1:30 PM, Baolin Wang wrote:
>> This patch introduces the usb charger support based on usb phy that
>> makes an enhancement to a power driver. The basic conception of the
>> usb charger is that, when one usb charger is added or removed by
>> reporting from the extcon device state change, the usb charger will
>> report to power user to set the current limitation.
>>
>> Power user can register a notifiee on the usb phy by issuing
>> usb_register_notifier() to get notified by charger status changes
>> or charger current changes.
>
> Why can't we use power_supply framework for this?
> Power user can register usb power_supply and USB PHY driver
> can update charging current using - power_supply_set_property().

No. We can get the current can be drawn from USB layer not from power
supply framework, moreover some USB controller can detect the charger
type and power supply framework can not. I think you missed lots of
previous discussion, maybe you can check below links to follow what we
have discussed before.
https://lists.gt.net/linux/kernel/2546730
https://patchwork.kernel.org/patch/9601973/


>> we can notify what current to be drawn to power user according to
>> different charger type, and now we have 2 methods to get charger type.
>> One is get charger type from extcon subsystem, which also means the
>> charger state changes. Another is we can get the charger type from
>> USB controller detecting or PMIC detecting, and the charger state
>> changes should be told by issuing usb_phy_set_charger_state().
>>
>> Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
>> ---
>>  drivers/usb/phy/phy.c   |  272 +++++++++++++++++++++++++++++++++++++++++++++++
>>  include/linux/usb/phy.h |   49 +++++++++
>
> --
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> a Linux Foundation Collaborative Project
>



-- 
Baolin.wang
Best Regards

[PATCH v3 3/3] power: wm831x_power: Support USB charger current limit management

[Baolin Wang]

Integrate with the newly added USB charger interface to limit the current
we draw from the USB input based on the input device configuration
identified by the USB stack, allowing us to charge more quickly from high
current inputs without drawing more current than specified from others.

Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
---
 Documentation/devicetree/bindings/mfd/wm831x.txt |    1 +
 drivers/power/supply/wm831x_power.c              |   58 ++++++++++++++++++++++
 2 files changed, 59 insertions(+)

diff --git a/Documentation/devicetree/bindings/mfd/wm831x.txt b/Documentation/devicetree/bindings/mfd/wm831x.txt
index 9f8b743..4e3bc07 100644
--- a/Documentation/devicetree/bindings/mfd/wm831x.txt
+++ b/Documentation/devicetree/bindings/mfd/wm831x.txt
@@ -31,6 +31,7 @@ Required properties:
     ../interrupt-controller/interrupts.txt
 
 Optional sub-nodes:
+  - usb-phy : Contains a phandle to the USB PHY.
   - regulators : Contains sub-nodes for each of the regulators supplied by
     the device. The regulators are bound using their names listed below:
 
diff --git a/drivers/power/supply/wm831x_power.c b/drivers/power/supply/wm831x_power.c
index 7082301..d3948ab 100644
--- a/drivers/power/supply/wm831x_power.c
+++ b/drivers/power/supply/wm831x_power.c
@@ -13,6 +13,7 @@
 #include <linux/platform_device.h>
 #include <linux/power_supply.h>
 #include <linux/slab.h>
+#include <linux/usb/phy.h>
 
 #include <linux/mfd/wm831x/core.h>
 #include <linux/mfd/wm831x/auxadc.h>
@@ -31,6 +32,8 @@ struct wm831x_power {
 	char usb_name[20];
 	char battery_name[20];
 	bool have_battery;
+	struct usb_phy *usb_phy;
+	struct notifier_block usb_notify;
 };
 
 static int wm831x_power_check_online(struct wm831x *wm831x, int supply,
@@ -125,6 +128,43 @@ static int wm831x_usb_get_prop(struct power_supply *psy,
 	POWER_SUPPLY_PROP_VOLTAGE_NOW,
 };
 
+/* In milliamps */
+static const unsigned int wm831x_usb_limits[] = {
+	0,
+	2,
+	100,
+	500,
+	900,
+	1500,
+	1800,
+	550,
+};
+
+static int wm831x_usb_limit_change(struct notifier_block *nb,
+				   unsigned long limit, void *data)
+{
+	struct wm831x_power *wm831x_power = container_of(nb,
+							 struct wm831x_power,
+							 usb_notify);
+	unsigned int i, best;
+
+	/* Find the highest supported limit */
+	best = 0;
+	for (i = 0; i < ARRAY_SIZE(wm831x_usb_limits); i++) {
+		if (limit >= wm831x_usb_limits[i] &&
+		    wm831x_usb_limits[best] < wm831x_usb_limits[i])
+			best = i;
+	}
+
+	dev_dbg(wm831x_power->wm831x->dev,
+		"Limiting USB current to %umA", wm831x_usb_limits[best]);
+
+	wm831x_set_bits(wm831x_power->wm831x, WM831X_POWER_STATE,
+		        WM831X_USB_ILIM_MASK, best);
+
+	return 0;
+}
+
 /*********************************************************************
  *		Battery properties
  *********************************************************************/
@@ -607,6 +647,19 @@ static int wm831x_power_probe(struct platform_device *pdev)
 		}
 	}
 
+	power->usb_phy = devm_usb_get_phy_by_phandle(&pdev->dev,
+						     "usb-phy", 0);
+	if (!IS_ERR(power->usb_phy)) {
+		power->usb_notify.notifier_call = wm831x_usb_limit_change;
+		ret = usb_register_notifier(power->usb_phy,
+					    &power->usb_notify);
+		if (ret) {
+			dev_err(&pdev->dev, "Failed to register notifier: %d\n",
+				ret);
+			goto err_bat_irq;
+		}
+	}
+
 	return ret;
 
 err_bat_irq:
@@ -637,6 +690,11 @@ static int wm831x_power_remove(struct platform_device *pdev)
 	struct wm831x *wm831x = wm831x_power->wm831x;
 	int irq, i;
 
+	if (!IS_ERR(wm831x_power->usb_phy)) {
+		usb_unregister_notifier(wm831x_power->usb_phy,
+					&wm831x_power->usb_notify);
+	}
+
 	for (i = 0; i < ARRAY_SIZE(wm831x_bat_irqs); i++) {
 		irq = wm831x_irq(wm831x, 
 				 platform_get_irq_byname(pdev,
-- 
1.7.9.5

Re: [PATCH v3 3/3] power: wm831x_power: Support USB charger current limit management

[Lee Jones]

On Tue, 25 Jul 2017, Baolin Wang wrote:

> Integrate with the newly added USB charger interface to limit the current
> we draw from the USB input based on the input device configuration
> identified by the USB stack, allowing us to charge more quickly from high
> current inputs without drawing more current than specified from others.
> 
> Signed-off-by: Mark Brown <broonie@kernel.org>
> Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
> ---
>  Documentation/devicetree/bindings/mfd/wm831x.txt |    1 +

Acked-by: Lee Jones <lee.jones@linaro.org>

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

Re: [PATCH v3 3/3] power: wm831x_power: Support USB charger current limit management

[Charles Keepax]

On Tue, Jul 25, 2017 at 04:00:01PM +0800, Baolin Wang wrote:
> Integrate with the newly added USB charger interface to limit the current
> we draw from the USB input based on the input device configuration
> identified by the USB stack, allowing us to charge more quickly from high
> current inputs without drawing more current than specified from others.
> 
> Signed-off-by: Mark Brown <broonie@kernel.org>
> Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
> ---

Acked-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>

Thanks,
Charles

Re: [PATCH v3 3/3] power: wm831x_power: Support USB charger current limit management

[Sebastian Reichel]

[-- Attachment #1: Type: text/plain, Size: 4464 bytes --]

Hi,

On Tue, Jul 25, 2017 at 04:00:01PM +0800, Baolin Wang wrote:
> Integrate with the newly added USB charger interface to limit the current
> we draw from the USB input based on the input device configuration
> identified by the USB stack, allowing us to charge more quickly from high
> current inputs without drawing more current than specified from others.
> 
> Signed-off-by: Mark Brown <broonie@kernel.org>
> Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
> ---
>  Documentation/devicetree/bindings/mfd/wm831x.txt |    1 +
>  drivers/power/supply/wm831x_power.c              |   58 ++++++++++++++++++++++
>  2 files changed, 59 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/mfd/wm831x.txt b/Documentation/devicetree/bindings/mfd/wm831x.txt
> index 9f8b743..4e3bc07 100644
> --- a/Documentation/devicetree/bindings/mfd/wm831x.txt
> +++ b/Documentation/devicetree/bindings/mfd/wm831x.txt
> @@ -31,6 +31,7 @@ Required properties:
>      ../interrupt-controller/interrupts.txt
>  
>  Optional sub-nodes:
> +  - usb-phy : Contains a phandle to the USB PHY.
>    - regulators : Contains sub-nodes for each of the regulators supplied by
>      the device. The regulators are bound using their names listed below:
>  
> diff --git a/drivers/power/supply/wm831x_power.c b/drivers/power/supply/wm831x_power.c
> index 7082301..d3948ab 100644
> --- a/drivers/power/supply/wm831x_power.c
> +++ b/drivers/power/supply/wm831x_power.c
> @@ -13,6 +13,7 @@
>  #include <linux/platform_device.h>
>  #include <linux/power_supply.h>
>  #include <linux/slab.h>
> +#include <linux/usb/phy.h>
>  
>  #include <linux/mfd/wm831x/core.h>
>  #include <linux/mfd/wm831x/auxadc.h>
> @@ -31,6 +32,8 @@ struct wm831x_power {
>  	char usb_name[20];
>  	char battery_name[20];
>  	bool have_battery;
> +	struct usb_phy *usb_phy;
> +	struct notifier_block usb_notify;
>  };
>  
>  static int wm831x_power_check_online(struct wm831x *wm831x, int supply,
> @@ -125,6 +128,43 @@ static int wm831x_usb_get_prop(struct power_supply *psy,
>  	POWER_SUPPLY_PROP_VOLTAGE_NOW,
>  };
>  
> +/* In milliamps */
> +static const unsigned int wm831x_usb_limits[] = {
> +	0,
> +	2,
> +	100,
> +	500,
> +	900,
> +	1500,
> +	1800,
> +	550,
> +};
> +
> +static int wm831x_usb_limit_change(struct notifier_block *nb,
> +				   unsigned long limit, void *data)
> +{
> +	struct wm831x_power *wm831x_power = container_of(nb,
> +							 struct wm831x_power,
> +							 usb_notify);
> +	unsigned int i, best;
> +
> +	/* Find the highest supported limit */
> +	best = 0;
> +	for (i = 0; i < ARRAY_SIZE(wm831x_usb_limits); i++) {
> +		if (limit >= wm831x_usb_limits[i] &&
> +		    wm831x_usb_limits[best] < wm831x_usb_limits[i])
> +			best = i;
> +	}
> +
> +	dev_dbg(wm831x_power->wm831x->dev,
> +		"Limiting USB current to %umA", wm831x_usb_limits[best]);
> +
> +	wm831x_set_bits(wm831x_power->wm831x, WM831X_POWER_STATE,
> +		        WM831X_USB_ILIM_MASK, best);
> +
> +	return 0;
> +}
> +
>  /*********************************************************************
>   *		Battery properties
>   *********************************************************************/
> @@ -607,6 +647,19 @@ static int wm831x_power_probe(struct platform_device *pdev)
>  		}
>  	}
>  
> +	power->usb_phy = devm_usb_get_phy_by_phandle(&pdev->dev,
> +						     "usb-phy", 0);
> +	if (!IS_ERR(power->usb_phy)) {
> +		power->usb_notify.notifier_call = wm831x_usb_limit_change;
> +		ret = usb_register_notifier(power->usb_phy,
> +					    &power->usb_notify);
> +		if (ret) {
> +			dev_err(&pdev->dev, "Failed to register notifier: %d\n",
> +				ret);
> +			goto err_bat_irq;
> +		}
> +	}

No error handling for power->usb_phy? I think you should bail out
for all errors except for "not defined in DT". Especially I would
expect probe defer handling in case the power supply driver is
loaded before the phy driver.

>  	return ret;
>  
>  err_bat_irq:
> @@ -637,6 +690,11 @@ static int wm831x_power_remove(struct platform_device *pdev)
>  	struct wm831x *wm831x = wm831x_power->wm831x;
>  	int irq, i;
>  
> +	if (!IS_ERR(wm831x_power->usb_phy)) {
> +		usb_unregister_notifier(wm831x_power->usb_phy,
> +					&wm831x_power->usb_notify);
> +	}
> +
>  	for (i = 0; i < ARRAY_SIZE(wm831x_bat_irqs); i++) {
>  		irq = wm831x_irq(wm831x, 
>  				 platform_get_irq_byname(pdev,

-- Sebastian

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]

Re: [PATCH v3 3/3] power: wm831x_power: Support USB charger current limit management

[Baolin Wang]

Hi,

On 25 July 2017 at 17:59, Sebastian Reichel
<sebastian.reichel-ZGY8ohtN/8pPYcu2f3hruQ@public.gmane.org> wrote:
> Hi,
>
> On Tue, Jul 25, 2017 at 04:00:01PM +0800, Baolin Wang wrote:
>> Integrate with the newly added USB charger interface to limit the current
>> we draw from the USB input based on the input device configuration
>> identified by the USB stack, allowing us to charge more quickly from high
>> current inputs without drawing more current than specified from others.
>>
>> Signed-off-by: Mark Brown <broonie-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
>> Signed-off-by: Baolin Wang <baolin.wang-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
>> ---
>>  Documentation/devicetree/bindings/mfd/wm831x.txt |    1 +
>>  drivers/power/supply/wm831x_power.c              |   58 ++++++++++++++++++++++
>>  2 files changed, 59 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/mfd/wm831x.txt b/Documentation/devicetree/bindings/mfd/wm831x.txt
>> index 9f8b743..4e3bc07 100644
>> --- a/Documentation/devicetree/bindings/mfd/wm831x.txt
>> +++ b/Documentation/devicetree/bindings/mfd/wm831x.txt
>> @@ -31,6 +31,7 @@ Required properties:
>>      ../interrupt-controller/interrupts.txt
>>
>>  Optional sub-nodes:
>> +  - usb-phy : Contains a phandle to the USB PHY.
>>    - regulators : Contains sub-nodes for each of the regulators supplied by
>>      the device. The regulators are bound using their names listed below:
>>
>> diff --git a/drivers/power/supply/wm831x_power.c b/drivers/power/supply/wm831x_power.c
>> index 7082301..d3948ab 100644
>> --- a/drivers/power/supply/wm831x_power.c
>> +++ b/drivers/power/supply/wm831x_power.c
>> @@ -13,6 +13,7 @@
>>  #include <linux/platform_device.h>
>>  #include <linux/power_supply.h>
>>  #include <linux/slab.h>
>> +#include <linux/usb/phy.h>
>>
>>  #include <linux/mfd/wm831x/core.h>
>>  #include <linux/mfd/wm831x/auxadc.h>
>> @@ -31,6 +32,8 @@ struct wm831x_power {
>>       char usb_name[20];
>>       char battery_name[20];
>>       bool have_battery;
>> +     struct usb_phy *usb_phy;
>> +     struct notifier_block usb_notify;
>>  };
>>
>>  static int wm831x_power_check_online(struct wm831x *wm831x, int supply,
>> @@ -125,6 +128,43 @@ static int wm831x_usb_get_prop(struct power_supply *psy,
>>       POWER_SUPPLY_PROP_VOLTAGE_NOW,
>>  };
>>
>> +/* In milliamps */
>> +static const unsigned int wm831x_usb_limits[] = {
>> +     0,
>> +     2,
>> +     100,
>> +     500,
>> +     900,
>> +     1500,
>> +     1800,
>> +     550,
>> +};
>> +
>> +static int wm831x_usb_limit_change(struct notifier_block *nb,
>> +                                unsigned long limit, void *data)
>> +{
>> +     struct wm831x_power *wm831x_power = container_of(nb,
>> +                                                      struct wm831x_power,
>> +                                                      usb_notify);
>> +     unsigned int i, best;
>> +
>> +     /* Find the highest supported limit */
>> +     best = 0;
>> +     for (i = 0; i < ARRAY_SIZE(wm831x_usb_limits); i++) {
>> +             if (limit >= wm831x_usb_limits[i] &&
>> +                 wm831x_usb_limits[best] < wm831x_usb_limits[i])
>> +                     best = i;
>> +     }
>> +
>> +     dev_dbg(wm831x_power->wm831x->dev,
>> +             "Limiting USB current to %umA", wm831x_usb_limits[best]);
>> +
>> +     wm831x_set_bits(wm831x_power->wm831x, WM831X_POWER_STATE,
>> +                     WM831X_USB_ILIM_MASK, best);
>> +
>> +     return 0;
>> +}
>> +
>>  /*********************************************************************
>>   *           Battery properties
>>   *********************************************************************/
>> @@ -607,6 +647,19 @@ static int wm831x_power_probe(struct platform_device *pdev)
>>               }
>>       }
>>
>> +     power->usb_phy = devm_usb_get_phy_by_phandle(&pdev->dev,
>> +                                                  "usb-phy", 0);
>> +     if (!IS_ERR(power->usb_phy)) {
>> +             power->usb_notify.notifier_call = wm831x_usb_limit_change;
>> +             ret = usb_register_notifier(power->usb_phy,
>> +                                         &power->usb_notify);
>> +             if (ret) {
>> +                     dev_err(&pdev->dev, "Failed to register notifier: %d\n",
>> +                             ret);
>> +                     goto err_bat_irq;
>> +             }
>> +     }
>
> No error handling for power->usb_phy? I think you should bail out
> for all errors except for "not defined in DT". Especially I would
> expect probe defer handling in case the power supply driver is
> loaded before the phy driver.

Make sense. So I think I need to change like below:

power->usb_phy = devm_usb_get_phy_by_phandle(&pdev->dev, "usb-phy", 0);
if (!IS_ERR(power->usb_phy)) {
        power->usb_notify.notifier_call = wm831x_usb_limit_change;
        ret = usb_register_notifier(power->usb_phy, &power->usb_notify);
        if (ret) {
                dev_err(&pdev->dev, "Failed to register notifier: %d\n", ret);
                goto err_bat_irq;
        }
} else if (PTR_ERR(power->usb_phy) != -ENODEV &&
PTR_ERR(power->usb_phy) != -EINVAL) {
       ret = PTR_ERR(power->usb_phy);
       dev_err(&pdev->dev, "Failed to find USB phy: %d\n", ret);
       goto err_bat_irq;
}

The return value -EINVAL means the platform device does not have a
device node and -ENODEV  means we did not set the 'usb-phy' phandle,
other errors we should bail out including -PROBE_DEFER. Is it OK for
you?

>
>>       return ret;
>>
>>  err_bat_irq:
>> @@ -637,6 +690,11 @@ static int wm831x_power_remove(struct platform_device *pdev)
>>       struct wm831x *wm831x = wm831x_power->wm831x;
>>       int irq, i;
>>
>> +     if (!IS_ERR(wm831x_power->usb_phy)) {
>> +             usb_unregister_notifier(wm831x_power->usb_phy,
>> +                                     &wm831x_power->usb_notify);
>> +     }
>> +
>>       for (i = 0; i < ARRAY_SIZE(wm831x_bat_irqs); i++) {
>>               irq = wm831x_irq(wm831x,
>>                                platform_get_irq_byname(pdev,
>
> -- Sebastian



-- 
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Re: [PATCH v3 3/3] power: wm831x_power: Support USB charger current limit management

[Sebastian Reichel]

[-- Attachment #1: Type: text/plain, Size: 6676 bytes --]

Hi,

On Wed, Jul 26, 2017 at 11:05:25AM +0800, Baolin Wang wrote:
> On 25 July 2017 at 17:59, Sebastian Reichel
> <sebastian.reichel@collabora.co.uk> wrote:
> > On Tue, Jul 25, 2017 at 04:00:01PM +0800, Baolin Wang wrote:
> >> Integrate with the newly added USB charger interface to limit the current
> >> we draw from the USB input based on the input device configuration
> >> identified by the USB stack, allowing us to charge more quickly from high
> >> current inputs without drawing more current than specified from others.
> >>
> >> Signed-off-by: Mark Brown <broonie@kernel.org>
> >> Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
> >> ---
> >>  Documentation/devicetree/bindings/mfd/wm831x.txt |    1 +
> >>  drivers/power/supply/wm831x_power.c              |   58 ++++++++++++++++++++++
> >>  2 files changed, 59 insertions(+)
> >>
> >> diff --git a/Documentation/devicetree/bindings/mfd/wm831x.txt b/Documentation/devicetree/bindings/mfd/wm831x.txt
> >> index 9f8b743..4e3bc07 100644
> >> --- a/Documentation/devicetree/bindings/mfd/wm831x.txt
> >> +++ b/Documentation/devicetree/bindings/mfd/wm831x.txt
> >> @@ -31,6 +31,7 @@ Required properties:
> >>      ../interrupt-controller/interrupts.txt
> >>
> >>  Optional sub-nodes:
> >> +  - usb-phy : Contains a phandle to the USB PHY.
> >>    - regulators : Contains sub-nodes for each of the regulators supplied by
> >>      the device. The regulators are bound using their names listed below:
> >>
> >> diff --git a/drivers/power/supply/wm831x_power.c b/drivers/power/supply/wm831x_power.c
> >> index 7082301..d3948ab 100644
> >> --- a/drivers/power/supply/wm831x_power.c
> >> +++ b/drivers/power/supply/wm831x_power.c
> >> @@ -13,6 +13,7 @@
> >>  #include <linux/platform_device.h>
> >>  #include <linux/power_supply.h>
> >>  #include <linux/slab.h>
> >> +#include <linux/usb/phy.h>
> >>
> >>  #include <linux/mfd/wm831x/core.h>
> >>  #include <linux/mfd/wm831x/auxadc.h>
> >> @@ -31,6 +32,8 @@ struct wm831x_power {
> >>       char usb_name[20];
> >>       char battery_name[20];
> >>       bool have_battery;
> >> +     struct usb_phy *usb_phy;
> >> +     struct notifier_block usb_notify;
> >>  };
> >>
> >>  static int wm831x_power_check_online(struct wm831x *wm831x, int supply,
> >> @@ -125,6 +128,43 @@ static int wm831x_usb_get_prop(struct power_supply *psy,
> >>       POWER_SUPPLY_PROP_VOLTAGE_NOW,
> >>  };
> >>
> >> +/* In milliamps */
> >> +static const unsigned int wm831x_usb_limits[] = {
> >> +     0,
> >> +     2,
> >> +     100,
> >> +     500,
> >> +     900,
> >> +     1500,
> >> +     1800,
> >> +     550,
> >> +};
> >> +
> >> +static int wm831x_usb_limit_change(struct notifier_block *nb,
> >> +                                unsigned long limit, void *data)
> >> +{
> >> +     struct wm831x_power *wm831x_power = container_of(nb,
> >> +                                                      struct wm831x_power,
> >> +                                                      usb_notify);
> >> +     unsigned int i, best;
> >> +
> >> +     /* Find the highest supported limit */
> >> +     best = 0;
> >> +     for (i = 0; i < ARRAY_SIZE(wm831x_usb_limits); i++) {
> >> +             if (limit >= wm831x_usb_limits[i] &&
> >> +                 wm831x_usb_limits[best] < wm831x_usb_limits[i])
> >> +                     best = i;
> >> +     }
> >> +
> >> +     dev_dbg(wm831x_power->wm831x->dev,
> >> +             "Limiting USB current to %umA", wm831x_usb_limits[best]);
> >> +
> >> +     wm831x_set_bits(wm831x_power->wm831x, WM831X_POWER_STATE,
> >> +                     WM831X_USB_ILIM_MASK, best);
> >> +
> >> +     return 0;
> >> +}
> >> +
> >>  /*********************************************************************
> >>   *           Battery properties
> >>   *********************************************************************/
> >> @@ -607,6 +647,19 @@ static int wm831x_power_probe(struct platform_device *pdev)
> >>               }
> >>       }
> >>
> >> +     power->usb_phy = devm_usb_get_phy_by_phandle(&pdev->dev,
> >> +                                                  "usb-phy", 0);
> >> +     if (!IS_ERR(power->usb_phy)) {
> >> +             power->usb_notify.notifier_call = wm831x_usb_limit_change;
> >> +             ret = usb_register_notifier(power->usb_phy,
> >> +                                         &power->usb_notify);
> >> +             if (ret) {
> >> +                     dev_err(&pdev->dev, "Failed to register notifier: %d\n",
> >> +                             ret);
> >> +                     goto err_bat_irq;
> >> +             }
> >> +     }
> >
> > No error handling for power->usb_phy? I think you should bail out
> > for all errors except for "not defined in DT". Especially I would
> > expect probe defer handling in case the power supply driver is
> > loaded before the phy driver.
> 
> Make sense. So I think I need to change like below:
> 
> power->usb_phy = devm_usb_get_phy_by_phandle(&pdev->dev, "usb-phy", 0);
> if (!IS_ERR(power->usb_phy)) {
>         power->usb_notify.notifier_call = wm831x_usb_limit_change;
>         ret = usb_register_notifier(power->usb_phy, &power->usb_notify);
>         if (ret) {
>                 dev_err(&pdev->dev, "Failed to register notifier: %d\n", ret);
>                 goto err_bat_irq;
>         }
> } else if (PTR_ERR(power->usb_phy) != -ENODEV &&
> PTR_ERR(power->usb_phy) != -EINVAL) {
>        ret = PTR_ERR(power->usb_phy);
>        dev_err(&pdev->dev, "Failed to find USB phy: %d\n", ret);
>        goto err_bat_irq;
> }
> 
> The return value -EINVAL means the platform device does not have a
> device node and -ENODEV  means we did not set the 'usb-phy' phandle,
> other errors we should bail out including -PROBE_DEFER. Is it OK for
> you?

Yes, but I think the following is better, which avoids
spamming the log with probe defer messages. 

power->usb_phy = devm_usb_get_phy_by_phandle(&pdev->dev, "usb-phy", 0);
ret = PTR_ERR_OR_ZERO(power->usb_phy);

switch (ret) {
case 0:
    power->usb_notify.notifier_call = wm831x_usb_limit_change;
    ret = usb_register_notifier(power->usb_phy, &power->usb_notify);
    if (ret) {
        dev_err(&pdev->dev, "Failed to register notifier: %d\n", ret);
        goto err_bat_irq;
    }
    break;
case -EINVAL:
case -ENODEV:
    /* ignore missing usb-phy, it's optional */
    power->usb_phy = NULL;
    break;
default:
    dev_err(&pdev->dev, "Failed to find USB phy: %d\n", ret);
    /* fall-through */
case -EPROBE_DEFER:
    goto err_bat_irq;
    break;
}

-- Sebastian

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Re: [PATCH v3 3/3] power: wm831x_power: Support USB charger current limit management

[Baolin Wang]

Hi,

On 26 July 2017 at 20:08, Sebastian Reichel
<sebastian.reichel@collabora.co.uk> wrote:
> Hi,
>
> On Wed, Jul 26, 2017 at 11:05:25AM +0800, Baolin Wang wrote:
>> On 25 July 2017 at 17:59, Sebastian Reichel
>> <sebastian.reichel@collabora.co.uk> wrote:
>> > On Tue, Jul 25, 2017 at 04:00:01PM +0800, Baolin Wang wrote:
>> >> Integrate with the newly added USB charger interface to limit the current
>> >> we draw from the USB input based on the input device configuration
>> >> identified by the USB stack, allowing us to charge more quickly from high
>> >> current inputs without drawing more current than specified from others.
>> >>
>> >> Signed-off-by: Mark Brown <broonie@kernel.org>
>> >> Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
>> >> ---
>> >>  Documentation/devicetree/bindings/mfd/wm831x.txt |    1 +
>> >>  drivers/power/supply/wm831x_power.c              |   58 ++++++++++++++++++++++
>> >>  2 files changed, 59 insertions(+)
>> >>
>> >> diff --git a/Documentation/devicetree/bindings/mfd/wm831x.txt b/Documentation/devicetree/bindings/mfd/wm831x.txt
>> >> index 9f8b743..4e3bc07 100644
>> >> --- a/Documentation/devicetree/bindings/mfd/wm831x.txt
>> >> +++ b/Documentation/devicetree/bindings/mfd/wm831x.txt
>> >> @@ -31,6 +31,7 @@ Required properties:
>> >>      ../interrupt-controller/interrupts.txt
>> >>
>> >>  Optional sub-nodes:
>> >> +  - usb-phy : Contains a phandle to the USB PHY.
>> >>    - regulators : Contains sub-nodes for each of the regulators supplied by
>> >>      the device. The regulators are bound using their names listed below:
>> >>
>> >> diff --git a/drivers/power/supply/wm831x_power.c b/drivers/power/supply/wm831x_power.c
>> >> index 7082301..d3948ab 100644
>> >> --- a/drivers/power/supply/wm831x_power.c
>> >> +++ b/drivers/power/supply/wm831x_power.c
>> >> @@ -13,6 +13,7 @@
>> >>  #include <linux/platform_device.h>
>> >>  #include <linux/power_supply.h>
>> >>  #include <linux/slab.h>
>> >> +#include <linux/usb/phy.h>
>> >>
>> >>  #include <linux/mfd/wm831x/core.h>
>> >>  #include <linux/mfd/wm831x/auxadc.h>
>> >> @@ -31,6 +32,8 @@ struct wm831x_power {
>> >>       char usb_name[20];
>> >>       char battery_name[20];
>> >>       bool have_battery;
>> >> +     struct usb_phy *usb_phy;
>> >> +     struct notifier_block usb_notify;
>> >>  };
>> >>
>> >>  static int wm831x_power_check_online(struct wm831x *wm831x, int supply,
>> >> @@ -125,6 +128,43 @@ static int wm831x_usb_get_prop(struct power_supply *psy,
>> >>       POWER_SUPPLY_PROP_VOLTAGE_NOW,
>> >>  };
>> >>
>> >> +/* In milliamps */
>> >> +static const unsigned int wm831x_usb_limits[] = {
>> >> +     0,
>> >> +     2,
>> >> +     100,
>> >> +     500,
>> >> +     900,
>> >> +     1500,
>> >> +     1800,
>> >> +     550,
>> >> +};
>> >> +
>> >> +static int wm831x_usb_limit_change(struct notifier_block *nb,
>> >> +                                unsigned long limit, void *data)
>> >> +{
>> >> +     struct wm831x_power *wm831x_power = container_of(nb,
>> >> +                                                      struct wm831x_power,
>> >> +                                                      usb_notify);
>> >> +     unsigned int i, best;
>> >> +
>> >> +     /* Find the highest supported limit */
>> >> +     best = 0;
>> >> +     for (i = 0; i < ARRAY_SIZE(wm831x_usb_limits); i++) {
>> >> +             if (limit >= wm831x_usb_limits[i] &&
>> >> +                 wm831x_usb_limits[best] < wm831x_usb_limits[i])
>> >> +                     best = i;
>> >> +     }
>> >> +
>> >> +     dev_dbg(wm831x_power->wm831x->dev,
>> >> +             "Limiting USB current to %umA", wm831x_usb_limits[best]);
>> >> +
>> >> +     wm831x_set_bits(wm831x_power->wm831x, WM831X_POWER_STATE,
>> >> +                     WM831X_USB_ILIM_MASK, best);
>> >> +
>> >> +     return 0;
>> >> +}
>> >> +
>> >>  /*********************************************************************
>> >>   *           Battery properties
>> >>   *********************************************************************/
>> >> @@ -607,6 +647,19 @@ static int wm831x_power_probe(struct platform_device *pdev)
>> >>               }
>> >>       }
>> >>
>> >> +     power->usb_phy = devm_usb_get_phy_by_phandle(&pdev->dev,
>> >> +                                                  "usb-phy", 0);
>> >> +     if (!IS_ERR(power->usb_phy)) {
>> >> +             power->usb_notify.notifier_call = wm831x_usb_limit_change;
>> >> +             ret = usb_register_notifier(power->usb_phy,
>> >> +                                         &power->usb_notify);
>> >> +             if (ret) {
>> >> +                     dev_err(&pdev->dev, "Failed to register notifier: %d\n",
>> >> +                             ret);
>> >> +                     goto err_bat_irq;
>> >> +             }
>> >> +     }
>> >
>> > No error handling for power->usb_phy? I think you should bail out
>> > for all errors except for "not defined in DT". Especially I would
>> > expect probe defer handling in case the power supply driver is
>> > loaded before the phy driver.
>>
>> Make sense. So I think I need to change like below:
>>
>> power->usb_phy = devm_usb_get_phy_by_phandle(&pdev->dev, "usb-phy", 0);
>> if (!IS_ERR(power->usb_phy)) {
>>         power->usb_notify.notifier_call = wm831x_usb_limit_change;
>>         ret = usb_register_notifier(power->usb_phy, &power->usb_notify);
>>         if (ret) {
>>                 dev_err(&pdev->dev, "Failed to register notifier: %d\n", ret);
>>                 goto err_bat_irq;
>>         }
>> } else if (PTR_ERR(power->usb_phy) != -ENODEV &&
>> PTR_ERR(power->usb_phy) != -EINVAL) {
>>        ret = PTR_ERR(power->usb_phy);
>>        dev_err(&pdev->dev, "Failed to find USB phy: %d\n", ret);
>>        goto err_bat_irq;
>> }
>>
>> The return value -EINVAL means the platform device does not have a
>> device node and -ENODEV  means we did not set the 'usb-phy' phandle,
>> other errors we should bail out including -PROBE_DEFER. Is it OK for
>> you?
>
> Yes, but I think the following is better, which avoids
> spamming the log with probe defer messages.
>
> power->usb_phy = devm_usb_get_phy_by_phandle(&pdev->dev, "usb-phy", 0);
> ret = PTR_ERR_OR_ZERO(power->usb_phy);
>
> switch (ret) {
> case 0:
>     power->usb_notify.notifier_call = wm831x_usb_limit_change;
>     ret = usb_register_notifier(power->usb_phy, &power->usb_notify);
>     if (ret) {
>         dev_err(&pdev->dev, "Failed to register notifier: %d\n", ret);
>         goto err_bat_irq;
>     }
>     break;
> case -EINVAL:
> case -ENODEV:
>     /* ignore missing usb-phy, it's optional */
>     power->usb_phy = NULL;
>     break;
> default:
>     dev_err(&pdev->dev, "Failed to find USB phy: %d\n", ret);
>     /* fall-through */
> case -EPROBE_DEFER:
>     goto err_bat_irq;
>     break;
> }

OK. Thanks.

-- 
Baolin.wang
Best Regards