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 <nota...@gmail.com>
---
This is v3 of BCI charger driver I first sent nearly a year ago [1].
I've updated it to use the new OTG notifiers for VBUS notifications,
however it still is not able to determine charge current to use.
For that reason there is now a temporary module param to enable USB
charging, until I can figure out how to get that info from the gadget
stack (hopefully Felipe can help me here).
Besides that it now uses threaded interrupts and makes use of charge
state change interrupt to notify power supply core.

For this driver to work, twl-core needs to be patched to register
correct platform device, and twl4030-irq needs to set COR bit
correctly (will send those patches to mfd).

[1] http://marc.info/?l=linux-omap&m=125933316000333&w=2

 drivers/power/Kconfig           |    6 +
 drivers/power/Makefile          |    1 +
 drivers/power/twl4030_charger.c |  575 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 582 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..75ed029
--- /dev/null
+++ b/drivers/power/twl4030_charger.c
@@ -0,0 +1,575 @@
+/*
+ * TWL4030/TPS65950 BCI (Battery Charger Interface) driver
+ *
+ * Copyright (C) 2010 Gražvydas Ignotas <nota...@gmail.com>
+ *
+ * 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 __devinit 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);
+
+       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;
+       }
+
+       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;
+       }
+
+#ifdef CONFIG_USB_OTG_UTILS
+       bci->transceiver = otg_get_transceiver();
+#endif
+       if (bci->transceiver != NULL) {
+               bci->otg_nb.notifier_call = twl4030_bci_usb_ncb;
+               blocking_notifier_chain_register(&bci->transceiver->notifier,
+                       &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:
+#ifdef CONFIG_USB_OTG_UTILS
+       if (bci->transceiver != NULL) {
+               blocking_notifier_chain_unregister(&bci->transceiver->notifier,
+                       &bci->otg_nb);
+               otg_put_transceiver(bci->transceiver);
+       }
+#endif
+       power_supply_unregister(&bci->usb);
+fail_register_usb:
+       power_supply_unregister(&bci->ac);
+fail_register_ac:
+       platform_set_drvdata(pdev, NULL);
+       free_irq(bci->irq_bci, bci);
+fail_bci_irq:
+       free_irq(bci->irq_chg, bci);
+fail_chg_irq:
+       kfree(bci);
+
+       return ret;
+}
+
+static int __devexit 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);
+
+#ifdef CONFIG_USB_OTG_UTILS
+       if (bci->transceiver != NULL) {
+               blocking_notifier_chain_unregister(&bci->transceiver->notifier,
+                       &bci->otg_nb);
+               otg_put_transceiver(bci->transceiver);
+       }
+#endif
+       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 = {
+       .probe          = twl4030_bci_probe,
+       .remove         = __devexit_p(twl4030_bci_remove),
+       .driver         = {
+               .name   = "twl4030_bci",
+               .owner  = THIS_MODULE,
+       },
+};
+
+static int __init twl4030_bci_init(void)
+{
+       return platform_driver_register(&twl4030_bci_driver);
+}
+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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