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Message-ID: <20200615140557.GA22781@duo.ucw.cz>
Date: Mon, 15 Jun 2020 16:05:57 +0200
From: Pavel Machek <pavel@....cz>
To: kernel list <linux-kernel@...r.kernel.org>,
linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
linux-omap@...r.kernel.org, tony@...mide.com, sre@...nel.org,
nekit1000@...il.com, mpartap@....net, merlijn@...zup.org,
martin_rysavy@...trum.cz, linux-pm@...r.kernel.org
Subject: [RFC] Limiting charge current on Droid 4 (and N900)
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@....cz>
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@...mide.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)
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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