[RFC] cpcap: allow modifying voltages and currents

[Pavel Machek]

Hi!

This allows user to disable the green LED, so that it can be used for
other notifications. It also allows him to set lower voltage limits,
and adjust current: lower current and voltage limits will result in
longer battery lifetime.

Currently I'm using

POWER_SUPPLY_PROP_CHARGE_CONTROL_LIMIT,
POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT,
POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE,

attributes to control it. Do we have something suitable for LED
control? Are the current/voltage limits ok to use?

Best regards,
								Pavel


diff --git a/drivers/power/supply/cpcap-battery.c b/drivers/power/supply/cpcap-battery.c
index 98ba078..839e365 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@xxxxxxxxxxx>
  *
- * 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 e4905be..7de07ae 100644
--- a/drivers/power/supply/cpcap-charger.c
+++ b/drivers/power/supply/cpcap-charger.c
@@ -93,6 +93,17 @@
 #define CPCAP_REG_CRM_VCHRG_4V42	CPCAP_REG_CRM_VCHRG(0xe)
 #define CPCAP_REG_CRM_VCHRG_4V44	CPCAP_REG_CRM_VCHRG(0xf)
 
+static int voltage_to_register(int microvolt)
+{
+	switch (microvolt/1000) {
+	case 3800: return CPCAP_REG_CRM_VCHRG_3V80;
+	case 4100: return CPCAP_REG_CRM_VCHRG_4V10;
+	case 4200: return CPCAP_REG_CRM_VCHRG_4V20;
+	case 4350: return CPCAP_REG_CRM_VCHRG_4V35;
+	default: return -EINVAL;
+	}
+}
+
 /*
  * CPCAP_REG_CRM charge currents. These seem to match MC13783UG.pdf
  * values in "Table 8-3. Charge Path Regulator Current Limit
@@ -116,6 +127,18 @@
 #define CPCAP_REG_CRM_ICHRG_1A596	CPCAP_REG_CRM_ICHRG(0xe)
 #define CPCAP_REG_CRM_ICHRG_NO_LIMIT	CPCAP_REG_CRM_ICHRG(0xf)
 
+static int current_to_register(int microamp)
+{
+	switch (microamp/1000) {
+	case 0:    return CPCAP_REG_CRM_ICHRG_0A000;
+	case 70:   return CPCAP_REG_CRM_ICHRG_0A070;
+	case 177:  return CPCAP_REG_CRM_ICHRG_0A177;
+	case 532:  return CPCAP_REG_CRM_ICHRG_0A532;
+	case 1596: return CPCAP_REG_CRM_ICHRG_1A596;
+	default: return -EINVAL;
+	}
+}
+
 enum {
 	CPCAP_CHARGER_IIO_BATTDET,
 	CPCAP_CHARGER_IIO_VOLTAGE,
@@ -142,6 +165,10 @@ struct cpcap_charger_ddata {
 	atomic_t active;
 
 	int status;
+
+	int led_enabled;
+	int limit_current;
+	int limit_voltage;
 };
 
 struct cpcap_interrupt_desc {
@@ -163,11 +190,17 @@ struct cpcap_charger_ints_state {
 	bool battdetb;
 };
 
+#define POWER_SUPPLY_PROP_INDICATION POWER_SUPPLY_PROP_CHARGE_CONTROL_LIMIT
+
 static enum power_supply_property cpcap_charger_props[] = {
 	POWER_SUPPLY_PROP_STATUS,
 	POWER_SUPPLY_PROP_ONLINE,
 	POWER_SUPPLY_PROP_VOLTAGE_NOW,
 	POWER_SUPPLY_PROP_CURRENT_NOW,
+
+        POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT,
+	POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE,
+	POWER_SUPPLY_PROP_INDICATION,
 };
 
 static bool cpcap_charger_battery_found(struct cpcap_charger_ddata *ddata)
@@ -229,6 +262,7 @@ static int cpcap_charger_get_property(struct power_supply *psy,
 		val->intval = ddata->status;
 		break;
 	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
+		/* FIXME? Display voltage even when not charging? */
 		if (ddata->status == POWER_SUPPLY_STATUS_CHARGING)
 			val->intval = cpcap_charger_get_charge_voltage(ddata) *
 				1000;
@@ -245,6 +279,50 @@ static int cpcap_charger_get_property(struct power_supply *psy,
 	case POWER_SUPPLY_PROP_ONLINE:
 		val->intval = ddata->status == POWER_SUPPLY_STATUS_CHARGING;
 		break;
+		
+	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT:
+		// -> charger -- current limit
+		val->intval = ddata->limit_current;
+		break;
+	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE:
+		val->intval = ddata->limit_voltage;
+		break;
+	case POWER_SUPPLY_PROP_INDICATION:
+		val->intval = ddata->led_enabled;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int cpcap_charger_set_property(struct power_supply *psy,
+				      enum power_supply_property psp,
+				      const union power_supply_propval *val)
+{
+	struct cpcap_charger_ddata *ddata = dev_get_drvdata(psy->dev.parent);
+
+	switch (psp) {
+	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT:
+		printk("charge current: %d\n", val->intval);
+		if (current_to_register(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:
+		printk("charge voltage: %d\n", val->intval);
+		if (voltage_to_register(val->intval) < 0)
+			return -EINVAL;
+		ddata->limit_voltage = val->intval;
+		schedule_delayed_work(&ddata->detect_work, 0);
+		break;
+	case POWER_SUPPLY_PROP_INDICATION:
+		printk("hack indication: %d\n", val->intval);
+		ddata->led_enabled = !!val->intval;
+		schedule_delayed_work(&ddata->detect_work, 0);
+		break;
 	default:
 		return -EINVAL;
 	}
@@ -296,7 +374,7 @@ static int cpcap_charger_set_state(struct cpcap_charger_ddata *ddata,
 	}
 
 	error = regmap_update_bits(ddata->reg, CPCAP_REG_CRM, 0x3fff,
-				   CPCAP_REG_CRM_CHRG_LED_EN |
+				   ddata->led_enabled * CPCAP_REG_CRM_CHRG_LED_EN |
 				   trickle_current |
 				   CPCAP_REG_CRM_FET_OVRD |
 				   CPCAP_REG_CRM_FET_CTRL |
@@ -440,16 +518,38 @@ static void cpcap_usb_detect(struct work_struct *work)
 		return;
 
 	if (cpcap_charger_vbus_valid(ddata) && s.chrgcurr1) {
-		int max_current;
+		int m_voltage, m_current;
+		int reg_current, reg_voltage;
 
 		if (cpcap_charger_battery_found(ddata))
-			max_current = CPCAP_REG_CRM_ICHRG_1A596;
+			m_current = 1596000;
 		else
-			max_current = CPCAP_REG_CRM_ICHRG_0A532;
+			m_current = 532000;
+
+		if (m_current > ddata->limit_current)
+			m_current = ddata->limit_current;
+		
+		m_voltage = 4350000;
+		if (m_voltage > ddata->limit_voltage)
+			m_voltage = ddata->limit_voltage;
+
+		printk("Charging, %d uV, %d uA\n", m_voltage, m_current);
+		
+		reg_voltage = voltage_to_register(m_voltage);
+		if (reg_voltage < 0) {
+			dev_err(ddata->dev, "%s impossible voltage\n", __func__);
+			return;
+		}
+			
+		reg_current = current_to_register(m_current);
+		if (reg_current < 0) {
+			dev_err(ddata->dev, "%s impossible current\n", __func__);
+			return;
+		}
 
 		error = cpcap_charger_set_state(ddata,
-						CPCAP_REG_CRM_VCHRG_4V35,
-						max_current, 0);
+						reg_voltage,
+						reg_current, 0);
 		if (error)
 			goto out_err;
 	} else {
@@ -579,12 +679,27 @@ static int cpcap_charger_init_iio(struct cpcap_charger_ddata *ddata)
 	return error;
 }
 
+static int cpcap_charger_property_is_writeable(struct power_supply *psy,
+						 enum power_supply_property psp)
+{
+	switch (psp) {
+	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT:
+	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE:
+	case POWER_SUPPLY_PROP_INDICATION:
+		return 1;
+	default:
+		return 0;
+	}
+}
+
 static const struct power_supply_desc cpcap_charger_usb_desc = {
 	.name		= "usb",
 	.type		= POWER_SUPPLY_TYPE_USB,
 	.properties	= cpcap_charger_props,
 	.num_properties	= ARRAY_SIZE(cpcap_charger_props),
 	.get_property	= cpcap_charger_get_property,
+	.set_property	= cpcap_charger_set_property,
+	.property_is_writeable = cpcap_charger_property_is_writeable,
 };
 
 #ifdef CONFIG_OF
@@ -619,6 +734,10 @@ static int cpcap_charger_probe(struct platform_device *pdev)
 	if (!ddata->reg)
 		return -ENODEV;
 
+	ddata->limit_current = 1596000;
+	ddata->limit_voltage = 4350000;
+	ddata->led_enabled = 1;
+
 	INIT_LIST_HEAD(&ddata->irq_list);
 	INIT_DELAYED_WORK(&ddata->detect_work, cpcap_usb_detect);
 	INIT_DELAYED_WORK(&ddata->vbus_work, cpcap_charger_vbus_work);

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

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