diff mbox series

[RFC] Limiting charge current on Droid 4 (and N900)

Message ID 20200615140557.GA22781@duo.ucw.cz
State New
Headers show
Series [RFC] Limiting charge current on Droid 4 (and N900) | expand

Commit Message

Pavel Machek June 15, 2020, 2:05 p.m. UTC 
Hi!

Droid 4 has same problem as N900: it is often neccessary to manually
tweak current draw from USB, for example when using thin charging cable.

N900 creates unique attribute by hand, but I believe
POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT looks suitable. (Should N900 be
converted?)

Comments? Would the patch be acceptable after fixing whitespace?

Best regards,
									Pavel

Signed-off-by: Pavel Machek <pavel@ucw.cz>

Comments

Pavel Machek Aug. 20, 2020, 6:58 a.m. UTC | #1 
Hi!

> > > Droid 4 has same problem as N900: it is often neccessary to manually

> > > tweak current draw from USB, for example when using thin charging cable.

> > > 

> > > N900 creates unique attribute by hand, but I believe

> > > POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT looks suitable. (Should N900 be

> > > converted?)

> > > 

> > > Comments? Would the patch be acceptable after fixing whitespace?

> > 

> > Looks OK to me. Until we have better charger vs host vs usb3 charging hub

> > detection in place this seems like a good thing to do.

> 

> FYI, I'm cleaning up the pending charger and battery patches to send out

> for review. So that includes my earlier RFC battery status patches, and

> Spinal's additions, and this patch. It will likely be several days before

> I have the series ready for posting though.


Thanks for heads-up.

I had issue when I could not charge _empty_ droid4 battery from
powerbank. Green light was blinking and current was going up and down
but never stabilized. I thought I had dmesg from that but can't find
it now :-(.

Plus, I left D4 on charger overnight, and found battery empty in the
morning. It apparently charged in the evening but then discharged.

Best regards,
									Pavel

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
diff mbox series

Patch

diff --git a/drivers/power/supply/cpcap-battery.c b/drivers/power/supply/cpcap-battery.c
index b16848cfb58c..39a00716372f 100644
--- a/drivers/power/supply/cpcap-battery.c
+++ b/drivers/power/supply/cpcap-battery.c
@@ -3,7 +3,7 @@ 
  *
  * Copyright (C) 2017 Tony Lindgren <tony@atomide.com>
  *
- * Some parts of the code based on earlie Motorola mapphone Linux kernel
+ * Some parts of the code based on earlier Motorola mapphone Linux kernel
  * drivers:
  *
  * Copyright (C) 2009-2010 Motorola, Inc.
diff --git a/drivers/power/supply/cpcap-charger.c b/drivers/power/supply/cpcap-charger.c
index cf1e05b511d9..292d7a31c663 100644
--- a/drivers/power/supply/cpcap-charger.c
+++ b/drivers/power/supply/cpcap-charger.c
@@ -89,6 +89,8 @@ 
  * CPCAP_REG_CRM charge currents. These seem to match MC13783UG.pdf
  * values in "Table 8-3. Charge Path Regulator Current Limit
  * Characteristics" for the nominal values.
+ *
+ * Except 70mA and 1.596A and unlimited, these are simply 88.7mA / step.
  */
 #define CPCAP_REG_CRM_ICHRG(val)	(((val) & 0xf) << 0)
 #define CPCAP_REG_CRM_ICHRG_0A000	CPCAP_REG_CRM_ICHRG(0x0)
@@ -147,6 +149,8 @@  struct cpcap_charger_ddata {
 	int status;
 	int state;
 	int voltage;
+	int limit_current;
+
 	int last_current;
 	int last_current_retries;
 };
@@ -175,6 +179,7 @@  static enum power_supply_property cpcap_charger_props[] = {
 	POWER_SUPPLY_PROP_STATUS,
 	POWER_SUPPLY_PROP_ONLINE,
 	POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE,
+	POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT,
 	POWER_SUPPLY_PROP_VOLTAGE_NOW,
 	POWER_SUPPLY_PROP_CURRENT_NOW,
 };
@@ -238,6 +243,9 @@  static int cpcap_charger_get_property(struct power_supply *psy,
 	case POWER_SUPPLY_PROP_STATUS:
 		val->intval = ddata->status;
 		break;
+  	case POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT:
+		val->intval = ddata->limit_current;
+		break;
 	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE:
 		val->intval = ddata->voltage;
 		break;
@@ -308,6 +316,25 @@  cpcap_charger_get_bat_const_charge_voltage(struct cpcap_charger_ddata *ddata)
 	return voltage;
 }
 
+static int cpcap_charger_current_to_regval(int microamp)
+{
+	int miliamp = microamp/1000;
+	int res;
+	if (miliamp < 0)
+		return -EINVAL;
+	if (miliamp < 70)
+		return CPCAP_REG_CRM_ICHRG(0x0);
+	if (miliamp < 177)
+		return CPCAP_REG_CRM_ICHRG(0x1);
+	if (miliamp > 1596)
+		return CPCAP_REG_CRM_ICHRG(0xe);
+
+	res = microamp / 88666;
+	if (res > 0xd)
+		res = 0xd;
+	return CPCAP_REG_CRM_ICHRG(res);
+}
+
 static int cpcap_charger_set_property(struct power_supply *psy,
 				      enum power_supply_property psp,
 				      const union power_supply_propval *val)
@@ -316,6 +343,12 @@  static int cpcap_charger_set_property(struct power_supply *psy,
 	int voltage, batvolt;
 
 	switch (psp) {
+  	case POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT:
+		if (cpcap_charger_current_to_regval(val->intval) < 0)
+			return -EINVAL;
+		ddata->limit_current = val->intval;
+		schedule_delayed_work(&ddata->detect_work, 0);
+		break;
 	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE:
 		voltage = cpcap_charger_match_voltage(val->intval);
 		batvolt = cpcap_charger_get_bat_const_charge_voltage(ddata);
@@ -335,6 +368,7 @@  static int cpcap_charger_property_is_writeable(struct power_supply *psy,
 					       enum power_supply_property psp)
 {
 	switch (psp) {
+	case POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT:
 	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE:
 		return 1;
 	default:
@@ -657,23 +691,21 @@  static void cpcap_usb_detect(struct work_struct *work)
 
 	if (!ddata->feeding_vbus && cpcap_charger_vbus_valid(ddata) &&
 	    s.chrgcurr1) {
-		int max_current;
-		int vchrg;
+		int max_current = 532000;
+		int vchrg, ichrg;
 
 		if (cpcap_charger_battery_found(ddata))
-			max_current = CPCAP_REG_CRM_ICHRG_1A596;
-		else
-			max_current = CPCAP_REG_CRM_ICHRG_0A532;
+			max_current = 1596000;
 
 		switch (ddata->state) {
 		case CPCAP_CHARGER_DETECTING:
 			ddata->last_current_retries = 0;
 			break;
 		case CPCAP_CHARGER_DISCONNECTED:
-			if (ddata->last_current > CPCAP_REG_CRM_ICHRG_0A532) {
+			if (ddata->last_current > 532000) {
 				/* Attempt current 3 times before lowering */
 				if (ddata->last_current_retries++ >= 3) {
-					ddata->last_current--;
+					ddata->last_current -= 100000;
 					ddata->last_current_retries = 0;
 					/* Wait a bit for voltage to ramp up */
 					usleep_range(40000, 50000);
@@ -688,11 +720,16 @@  static void cpcap_usb_detect(struct work_struct *work)
 			break;
 		}
 
+		if (max_current > ddata->limit_current)
+			max_current = ddata->limit_current;
+
 		ddata->last_current = max_current;
+
+		ichrg = cpcap_charger_current_to_regval(max_current);
 		vchrg = cpcap_charger_voltage_to_regval(ddata->voltage);
 		error = cpcap_charger_set_state(ddata,
 						CPCAP_REG_CRM_VCHRG(vchrg),
-						max_current, 0);
+						ichrg, 0);
 		if (error)
 			goto out_err;
 		cpcap_charger_update_state(ddata, CPCAP_CHARGER_CHARGING);
@@ -864,6 +901,7 @@  static int cpcap_charger_probe(struct platform_device *pdev)
 
 	ddata->dev = &pdev->dev;
 	ddata->voltage = 4200000;
+	ddata->limit_current = 532000;
 
 	ddata->reg = dev_get_regmap(ddata->dev->parent, NULL);
 	if (!ddata->reg)