[PATCH v4] power_supply: Add driver for TWL4030/TPS65950 BCI charger

[Grazvydas Ignotas]

TWL4030/TPS65950 is a multi-function device with integrated charger,
which allows charging from AC or USB. This driver enables the
charger and provides several monitoring functions.

Tested on OMAP3 Pandora board.

Signed-off-by: Grazvydas Ignotas <notasas@xxxxxxxxx>
---
changes since v3 [1]:
- register power supply before enabling interrupts
- use platform_driver_probe
- get rid of ifdefs

[1] http://marc.info/?l=linux-kernel&m=128552976908093&w=2

 drivers/power/Kconfig           |    6 +
 drivers/power/Makefile          |    1 +
 drivers/power/twl4030_charger.c |  565 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 572 insertions(+), 0 deletions(-)
 create mode 100644 drivers/power/twl4030_charger.c

diff --git a/drivers/power/Kconfig b/drivers/power/Kconfig
index 4d9a637..11eec62 100644
--- a/drivers/power/Kconfig
+++ b/drivers/power/Kconfig
@@ -180,4 +180,10 @@ config CHARGER_ISP1704
 	  Say Y to enable support for USB Charger Detection with
 	  ISP1707/ISP1704 USB transceivers.
 
+config CHARGER_TWL4030
+	tristate "OMAP TWL4030 BCI charger driver"
+	depends on TWL4030_CORE
+	help
+	  Say Y here to enable support for TWL4030 Battery Charge Interface.
+
 endif # POWER_SUPPLY
diff --git a/drivers/power/Makefile b/drivers/power/Makefile
index 2799a84..695e54f 100644
--- a/drivers/power/Makefile
+++ b/drivers/power/Makefile
@@ -39,3 +39,4 @@ obj-$(CONFIG_CHARGER_PCF50633)	+= pcf50633-charger.o
 obj-$(CONFIG_BATTERY_JZ4740)	+= jz4740-battery.o
 obj-$(CONFIG_BATTERY_INTEL_MID)	+= intel_mid_battery.o
 obj-$(CONFIG_CHARGER_ISP1704)	+= isp1704_charger.o
+obj-$(CONFIG_CHARGER_TWL4030)	+= twl4030_charger.o
diff --git a/drivers/power/twl4030_charger.c b/drivers/power/twl4030_charger.c
new file mode 100644
index 0000000..ff1f423
--- /dev/null
+++ b/drivers/power/twl4030_charger.c
@@ -0,0 +1,565 @@
+/*
+ * TWL4030/TPS65950 BCI (Battery Charger Interface) driver
+ *
+ * Copyright (C) 2010 Gražvydas Ignotas <notasas@xxxxxxxxx>
+ *
+ * based on twl4030_bci_battery.c by TI
+ * Copyright (C) 2008 Texas Instruments, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/platform_device.h>
+#include <linux/interrupt.h>
+#include <linux/i2c/twl.h>
+#include <linux/power_supply.h>
+#include <linux/notifier.h>
+#include <linux/usb/otg.h>
+
+#define TWL4030_BCIMSTATEC	0x02
+#define TWL4030_BCIICHG		0x08
+#define TWL4030_BCIVAC		0x0a
+#define TWL4030_BCIVBUS		0x0c
+#define TWL4030_BCIMFSTS4	0x10
+#define TWL4030_BCICTL1		0x23
+
+#define TWL4030_BCIAUTOWEN	BIT(5)
+#define TWL4030_CONFIG_DONE	BIT(4)
+#define TWL4030_BCIAUTOUSB	BIT(1)
+#define TWL4030_BCIAUTOAC	BIT(0)
+#define TWL4030_CGAIN		BIT(5)
+#define TWL4030_USBFASTMCHG	BIT(2)
+#define TWL4030_STS_VBUS	BIT(7)
+#define TWL4030_STS_USB_ID	BIT(2)
+
+/* BCI interrupts */
+#define TWL4030_WOVF		BIT(0) /* Watchdog overflow */
+#define TWL4030_TMOVF		BIT(1) /* Timer overflow */
+#define TWL4030_ICHGHIGH	BIT(2) /* Battery charge current high */
+#define TWL4030_ICHGLOW		BIT(3) /* Battery cc. low / FSM state change */
+#define TWL4030_ICHGEOC		BIT(4) /* Battery current end-of-charge */
+#define TWL4030_TBATOR2		BIT(5) /* Battery temperature out of range 2 */
+#define TWL4030_TBATOR1		BIT(6) /* Battery temperature out of range 1 */
+#define TWL4030_BATSTS		BIT(7) /* Battery status */
+
+#define TWL4030_VBATLVL		BIT(0) /* VBAT level */
+#define TWL4030_VBATOV		BIT(1) /* VBAT overvoltage */
+#define TWL4030_VBUSOV		BIT(2) /* VBUS overvoltage */
+#define TWL4030_ACCHGOV		BIT(3) /* Ac charger overvoltage */
+
+#define TWL4030_MSTATEC_USB		BIT(4)
+#define TWL4030_MSTATEC_AC		BIT(5)
+#define TWL4030_MSTATEC_MASK		0x0f
+#define TWL4030_MSTATEC_QUICK1		0x02
+#define TWL4030_MSTATEC_QUICK7		0x07
+#define TWL4030_MSTATEC_COMPLETE1	0x0b
+#define TWL4030_MSTATEC_COMPLETE4	0x0e
+
+static bool allow_usb;
+module_param(allow_usb, bool, 1);
+MODULE_PARM_DESC(allow_usb, "Allow USB charge drawing default current");
+
+struct twl4030_bci {
+	struct device		*dev;
+	struct power_supply	ac;
+	struct power_supply	usb;
+	struct otg_transceiver	*transceiver;
+	struct notifier_block	otg_nb;
+	int			irq_chg;
+	int			irq_bci;
+};
+
+/*
+ * clear and set bits on an given register on a given module
+ */
+static int twl4030_clear_set(u8 mod_no, u8 clear, u8 set, u8 reg)
+{
+	u8 val = 0;
+	int ret;
+
+	ret = twl_i2c_read_u8(mod_no, &val, reg);
+	if (ret)
+		return ret;
+
+	val &= ~clear;
+	val |= set;
+
+	return twl_i2c_write_u8(mod_no, val, reg);
+}
+
+static int twl4030_bci_read(u8 reg, u8 *val)
+{
+	return twl_i2c_read_u8(TWL4030_MODULE_MAIN_CHARGE, val, reg);
+}
+
+static int twl4030_clear_set_boot_bci(u8 clear, u8 set)
+{
+	return twl4030_clear_set(TWL4030_MODULE_PM_MASTER, 0,
+			TWL4030_CONFIG_DONE | TWL4030_BCIAUTOWEN | set,
+			TWL4030_PM_MASTER_BOOT_BCI);
+}
+
+static int twl4030bci_read_adc_val(u8 reg)
+{
+	int ret, temp;
+	u8 val;
+
+	/* read MSB */
+	ret = twl4030_bci_read(reg + 1, &val);
+	if (ret)
+		return ret;
+
+	temp = (int)(val & 0x03) << 8;
+
+	/* read LSB */
+	ret = twl4030_bci_read(reg, &val);
+	if (ret)
+		return ret;
+
+	return temp | val;
+}
+
+/*
+ * Check if VBUS power is present
+ */
+static int twl4030_bci_have_vbus(struct twl4030_bci *bci)
+{
+	int ret;
+	u8 hwsts;
+
+	ret = twl_i2c_read_u8(TWL4030_MODULE_PM_MASTER, &hwsts,
+			      TWL4030_PM_MASTER_STS_HW_CONDITIONS);
+	if (ret < 0)
+		return 0;
+
+	dev_dbg(bci->dev, "check_vbus: HW_CONDITIONS %02x\n", hwsts);
+
+	/* in case we also have STS_USB_ID, VBUS is driven by TWL itself */
+	if ((hwsts & TWL4030_STS_VBUS) && !(hwsts & TWL4030_STS_USB_ID))
+		return 1;
+
+	return 0;
+}
+
+/*
+ * Enable/Disable USB Charge funtionality.
+ */
+static int twl4030_charger_enable_usb(struct twl4030_bci *bci, bool enable)
+{
+	int ret;
+
+	if (enable) {
+		/* Check for USB charger conneted */
+		if (!twl4030_bci_have_vbus(bci))
+			return -ENODEV;
+
+		/*
+		 * Until we can find out what current the device can provide,
+		 * require a module param to enable USB charging.
+		 */
+		if (!allow_usb) {
+			dev_warn(bci->dev, "USB charging is disabled.\n");
+			return -EACCES;
+		}
+
+		/* forcing the field BCIAUTOUSB (BOOT_BCI[1]) to 1 */
+		ret = twl4030_clear_set_boot_bci(0, TWL4030_BCIAUTOUSB);
+		if (ret < 0)
+			return ret;
+
+		/* forcing USBFASTMCHG(BCIMFSTS4[2]) to 1 */
+		ret = twl4030_clear_set(TWL4030_MODULE_MAIN_CHARGE, 0,
+			TWL4030_USBFASTMCHG, TWL4030_BCIMFSTS4);
+	} else {
+		ret = twl4030_clear_set_boot_bci(TWL4030_BCIAUTOUSB, 0);
+	}
+
+	return ret;
+}
+
+/*
+ * Enable/Disable AC Charge funtionality.
+ */
+static int twl4030_charger_enable_ac(bool enable)
+{
+	int ret;
+
+	if (enable)
+		ret = twl4030_clear_set_boot_bci(0, TWL4030_BCIAUTOAC);
+	else
+		ret = twl4030_clear_set_boot_bci(TWL4030_BCIAUTOAC, 0);
+
+	return ret;
+}
+
+/*
+ * TWL4030 CHG_PRES (AC charger presence) events
+ */
+static irqreturn_t twl4030_charger_interrupt(int irq, void *arg)
+{
+	struct twl4030_bci *bci = arg;
+
+	dev_dbg(bci->dev, "CHG_PRES irq\n");
+	power_supply_changed(&bci->ac);
+	power_supply_changed(&bci->usb);
+
+	return IRQ_HANDLED;
+}
+
+/*
+ * TWL4030 BCI monitoring events
+ */
+static irqreturn_t twl4030_bci_interrupt(int irq, void *arg)
+{
+	struct twl4030_bci *bci = arg;
+	u8 irqs1, irqs2;
+	int ret;
+
+	ret = twl_i2c_read_u8(TWL4030_MODULE_INTERRUPTS, &irqs1,
+			      TWL4030_INTERRUPTS_BCIISR1A);
+	if (ret < 0)
+		return IRQ_HANDLED;
+
+	ret = twl_i2c_read_u8(TWL4030_MODULE_INTERRUPTS, &irqs2,
+			      TWL4030_INTERRUPTS_BCIISR2A);
+	if (ret < 0)
+		return IRQ_HANDLED;
+
+	dev_dbg(bci->dev, "BCI irq %02x %02x\n", irqs2, irqs1);
+
+	if (irqs1 & (TWL4030_ICHGLOW | TWL4030_ICHGEOC)) {
+		/* charger state change, inform the core */
+		power_supply_changed(&bci->ac);
+		power_supply_changed(&bci->usb);
+	}
+
+	/* various monitoring events, for now we just log them here */
+	if (irqs1 & (TWL4030_TBATOR2 | TWL4030_TBATOR1))
+		dev_warn(bci->dev, "battery temperature out of range\n");
+
+	if (irqs1 & TWL4030_BATSTS)
+		dev_crit(bci->dev, "battery disconnected\n");
+
+	if (irqs2 & TWL4030_VBATOV)
+		dev_crit(bci->dev, "VBAT overvoltage\n");
+
+	if (irqs2 & TWL4030_VBUSOV)
+		dev_crit(bci->dev, "VBUS overvoltage\n");
+
+	if (irqs2 & TWL4030_ACCHGOV)
+		dev_crit(bci->dev, "Ac charger overvoltage\n");
+
+	return IRQ_HANDLED;
+}
+
+static int twl4030_bci_usb_ncb(struct notifier_block *nb, unsigned long val,
+			       void *priv)
+{
+	struct twl4030_bci *bci = container_of(nb, struct twl4030_bci, otg_nb);
+
+	dev_dbg(bci->dev, "OTG notify %lu\n", val);
+
+	switch (val) {
+	case USB_EVENT_VBUS:
+	case USB_EVENT_CHARGER:
+		twl4030_charger_enable_usb(bci, true);
+		break;
+	case USB_EVENT_NONE:
+		twl4030_charger_enable_usb(bci, false);
+		break;
+	}
+
+	return NOTIFY_OK;
+}
+
+/*
+ * TI provided formulas:
+ * CGAIN == 0: ICHG = (BCIICHG * 1.7) / (2^10 - 1) - 0.85
+ * CGAIN == 1: ICHG = (BCIICHG * 3.4) / (2^10 - 1) - 1.7
+ * Here we use integer approximation of:
+ * CGAIN == 0: val * 1.6618 - 0.85
+ * CGAIN == 1: (val * 1.6618 - 0.85) * 2
+ */
+static int twl4030_charger_get_current(void)
+{
+	int curr;
+	int ret;
+	u8 bcictl1;
+
+	curr = twl4030bci_read_adc_val(TWL4030_BCIICHG);
+	if (curr < 0)
+		return curr;
+
+	ret = twl4030_bci_read(TWL4030_BCICTL1, &bcictl1);
+	if (ret)
+		return ret;
+
+	ret = (curr * 16618 - 850 * 10000) / 10;
+	if (bcictl1 & TWL4030_CGAIN)
+		ret *= 2;
+
+	return ret;
+}
+
+/*
+ * Returns the main charge FSM state
+ * Or < 0 on failure.
+ */
+static int twl4030bci_state(struct twl4030_bci *bci)
+{
+	int ret;
+	u8 state;
+
+	ret = twl4030_bci_read(TWL4030_BCIMSTATEC, &state);
+	if (ret) {
+		pr_err("twl4030_bci: error reading BCIMSTATEC\n");
+		return ret;
+	}
+
+	dev_dbg(bci->dev, "state: %02x\n", state);
+
+	return state;
+}
+
+static int twl4030_bci_state_to_status(int state)
+{
+	state &= TWL4030_MSTATEC_MASK;
+	if (TWL4030_MSTATEC_QUICK1 <= state && state <= TWL4030_MSTATEC_QUICK7)
+		return POWER_SUPPLY_STATUS_CHARGING;
+	else if (TWL4030_MSTATEC_COMPLETE1 <= state &&
+					state <= TWL4030_MSTATEC_COMPLETE4)
+		return POWER_SUPPLY_STATUS_FULL;
+	else
+		return POWER_SUPPLY_STATUS_NOT_CHARGING;
+}
+
+static int twl4030_bci_get_property(struct power_supply *psy,
+				    enum power_supply_property psp,
+				    union power_supply_propval *val)
+{
+	struct twl4030_bci *bci = dev_get_drvdata(psy->dev->parent);
+	int is_charging;
+	int state;
+	int ret;
+
+	state = twl4030bci_state(bci);
+	if (state < 0)
+		return state;
+
+	if (psy->type == POWER_SUPPLY_TYPE_USB)
+		is_charging = state & TWL4030_MSTATEC_USB;
+	else
+		is_charging = state & TWL4030_MSTATEC_AC;
+
+	switch (psp) {
+	case POWER_SUPPLY_PROP_STATUS:
+		if (is_charging)
+			val->intval = twl4030_bci_state_to_status(state);
+		else
+			val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
+		break;
+	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
+		/* charging must be active for meaningful result */
+		if (!is_charging)
+			return -ENODATA;
+		if (psy->type == POWER_SUPPLY_TYPE_USB) {
+			ret = twl4030bci_read_adc_val(TWL4030_BCIVBUS);
+			if (ret < 0)
+				return ret;
+			/* BCIVBUS uses ADCIN8, 7/1023 V/step */
+			val->intval = ret * 6843;
+		} else {
+			ret = twl4030bci_read_adc_val(TWL4030_BCIVAC);
+			if (ret < 0)
+				return ret;
+			/* BCIVAC uses ADCIN11, 10/1023 V/step */
+			val->intval = ret * 9775;
+		}
+		break;
+	case POWER_SUPPLY_PROP_CURRENT_NOW:
+		if (!is_charging)
+			return -ENODATA;
+		/* current measurement is shared between AC and USB */
+		ret = twl4030_charger_get_current();
+		if (ret < 0)
+			return ret;
+		val->intval = ret;
+		break;
+	case POWER_SUPPLY_PROP_ONLINE:
+		val->intval = is_charging &&
+			twl4030_bci_state_to_status(state) !=
+				POWER_SUPPLY_STATUS_NOT_CHARGING;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static enum power_supply_property twl4030_charger_props[] = {
+	POWER_SUPPLY_PROP_STATUS,
+	POWER_SUPPLY_PROP_ONLINE,
+	POWER_SUPPLY_PROP_VOLTAGE_NOW,
+	POWER_SUPPLY_PROP_CURRENT_NOW,
+};
+
+static int __init twl4030_bci_probe(struct platform_device *pdev)
+{
+	struct twl4030_bci *bci;
+	int ret;
+	int reg;
+
+	bci = kzalloc(sizeof(*bci), GFP_KERNEL);
+	if (bci == NULL)
+		return -ENOMEM;
+
+	bci->dev = &pdev->dev;
+	bci->irq_chg = platform_get_irq(pdev, 0);
+	bci->irq_bci = platform_get_irq(pdev, 1);
+
+	platform_set_drvdata(pdev, bci);
+
+	bci->ac.name = "twl4030_ac";
+	bci->ac.type = POWER_SUPPLY_TYPE_MAINS;
+	bci->ac.properties = twl4030_charger_props;
+	bci->ac.num_properties = ARRAY_SIZE(twl4030_charger_props);
+	bci->ac.get_property = twl4030_bci_get_property;
+
+	ret = power_supply_register(&pdev->dev, &bci->ac);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to register ac: %d\n", ret);
+		goto fail_register_ac;
+	}
+
+	bci->usb.name = "twl4030_usb";
+	bci->usb.type = POWER_SUPPLY_TYPE_USB;
+	bci->usb.properties = twl4030_charger_props;
+	bci->usb.num_properties = ARRAY_SIZE(twl4030_charger_props);
+	bci->usb.get_property = twl4030_bci_get_property;
+
+	ret = power_supply_register(&pdev->dev, &bci->usb);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to register usb: %d\n", ret);
+		goto fail_register_usb;
+	}
+
+	ret = request_threaded_irq(bci->irq_chg, NULL,
+			twl4030_charger_interrupt, 0, pdev->name, bci);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "could not request irq %d, status %d\n",
+			bci->irq_chg, ret);
+		goto fail_chg_irq;
+	}
+
+	ret = request_threaded_irq(bci->irq_bci, NULL,
+			twl4030_bci_interrupt, 0, pdev->name, bci);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "could not request irq %d, status %d\n",
+			bci->irq_bci, ret);
+		goto fail_bci_irq;
+	}
+
+	bci->transceiver = otg_get_transceiver();
+	if (bci->transceiver != NULL) {
+		bci->otg_nb.notifier_call = twl4030_bci_usb_ncb;
+		otg_register_notifier(bci->transceiver, &bci->otg_nb);
+	}
+
+	/* Enable interrupts now. */
+	reg = ~(TWL4030_ICHGLOW | TWL4030_ICHGEOC | TWL4030_TBATOR2 |
+		TWL4030_TBATOR1 | TWL4030_BATSTS);
+	ret = twl_i2c_write_u8(TWL4030_MODULE_INTERRUPTS, reg,
+			       TWL4030_INTERRUPTS_BCIIMR1A);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "failed to unmask interrupts: %d\n", ret);
+		goto fail_unmask_interrupts;
+	}
+
+	reg = ~(TWL4030_VBATOV | TWL4030_VBUSOV | TWL4030_ACCHGOV);
+	ret = twl_i2c_write_u8(TWL4030_MODULE_INTERRUPTS, reg,
+			       TWL4030_INTERRUPTS_BCIIMR2A);
+	if (ret < 0)
+		dev_warn(&pdev->dev, "failed to unmask interrupts: %d\n", ret);
+
+	twl4030_charger_enable_ac(true);
+	twl4030_charger_enable_usb(bci, true);
+
+	return 0;
+
+fail_unmask_interrupts:
+	if (bci->transceiver != NULL) {
+		otg_unregister_notifier(bci->transceiver, &bci->otg_nb);
+		otg_put_transceiver(bci->transceiver);
+	}
+	free_irq(bci->irq_bci, bci);
+fail_bci_irq:
+	free_irq(bci->irq_chg, bci);
+fail_chg_irq:
+	power_supply_unregister(&bci->usb);
+fail_register_usb:
+	power_supply_unregister(&bci->ac);
+fail_register_ac:
+	platform_set_drvdata(pdev, NULL);
+	kfree(bci);
+
+	return ret;
+}
+
+static int __exit twl4030_bci_remove(struct platform_device *pdev)
+{
+	struct twl4030_bci *bci = platform_get_drvdata(pdev);
+
+	twl4030_charger_enable_ac(false);
+	twl4030_charger_enable_usb(bci, false);
+
+	/* mask interrupts */
+	twl_i2c_write_u8(TWL4030_MODULE_INTERRUPTS, 0xff,
+			 TWL4030_INTERRUPTS_BCIIMR1A);
+	twl_i2c_write_u8(TWL4030_MODULE_INTERRUPTS, 0xff,
+			 TWL4030_INTERRUPTS_BCIIMR2A);
+
+	if (bci->transceiver != NULL) {
+		otg_unregister_notifier(bci->transceiver, &bci->otg_nb);
+		otg_put_transceiver(bci->transceiver);
+	}
+	free_irq(bci->irq_bci, bci);
+	free_irq(bci->irq_chg, bci);
+	power_supply_unregister(&bci->usb);
+	power_supply_unregister(&bci->ac);
+	platform_set_drvdata(pdev, NULL);
+	kfree(bci);
+
+	return 0;
+}
+
+static struct platform_driver twl4030_bci_driver = {
+	.driver	= {
+		.name	= "twl4030_bci",
+		.owner	= THIS_MODULE,
+	},
+	.remove	= __exit_p(twl4030_bci_remove),
+};
+
+static int __init twl4030_bci_init(void)
+{
+	return platform_driver_probe(&twl4030_bci_driver, twl4030_bci_probe);
+}
+module_init(twl4030_bci_init);
+
+static void __exit twl4030_bci_exit(void)
+{
+	platform_driver_unregister(&twl4030_bci_driver);
+}
+module_exit(twl4030_bci_exit);
+
+MODULE_AUTHOR("Gražydas Ignotas");
+MODULE_DESCRIPTION("TWL4030 Battery Charger Interface driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:twl4030_bci");
-- 
1.6.3.3

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