twl4030_charger.c

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/*
 * TWL4030/TPS65950 BCI (Battery Charger Interface) driver
 *
 * Copyright (C) 2010 Gražvydas Ignotas <[email protected]>
 *
 * 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/err.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>
#include <linux/regulator/machine.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_BB_CFG      0x12

#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)
#define TWL4030_BBCHEN      BIT(4)
#define TWL4030_BBSEL_MASK  0x0c
#define TWL4030_BBSEL_2V5   0x00
#define TWL4030_BBSEL_3V0   0x04
#define TWL4030_BBSEL_3V1   0x08
#define TWL4030_BBSEL_3V2   0x0c
#define TWL4030_BBISEL_MASK 0x03
#define TWL4030_BBISEL_25uA 0x00
#define TWL4030_BBISEL_150uA    0x01
#define TWL4030_BBISEL_500uA    0x02
#define TWL4030_BBISEL_1000uA   0x03

/* 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, 0644);
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 usb_phy      *transceiver;
    struct notifier_block   usb_nb;
    struct work_struct  work;
    int         irq_chg;
    int         irq_bci;
    struct regulator    *usb_reg;
    int         usb_enabled;

    unsigned long       event;
};

/*
 * 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, clear,
            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 functionality.
 */
static int twl4030_charger_enable_usb(struct twl4030_bci *bci, bool enable)
{
    int ret;

    if (enable) {
        /* Check for USB charger connected */
        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;
        }

        /* Need to keep regulator on */
        if (!bci->usb_enabled) {
            regulator_enable(bci->usb_reg);
            bci->usb_enabled = 1;
        }

        /* 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);
        if (bci->usb_enabled) {
            regulator_disable(bci->usb_reg);
            bci->usb_enabled = 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;
}

/*
 * Enable/Disable charging of Backup Battery.
 */
static int twl4030_charger_enable_backup(int uvolt, int uamp)
{
    int ret;
    u8 flags;

    if (uvolt < 2500000 ||
        uamp < 25) {
        /* disable charging of backup battery */
        ret = twl4030_clear_set(TWL4030_MODULE_PM_RECEIVER,
                    TWL4030_BBCHEN, 0, TWL4030_BB_CFG);
        return ret;
    }

    flags = TWL4030_BBCHEN;
    if (uvolt >= 3200000)
        flags |= TWL4030_BBSEL_3V2;
    else if (uvolt >= 3100000)
        flags |= TWL4030_BBSEL_3V1;
    else if (uvolt >= 3000000)
        flags |= TWL4030_BBSEL_3V0;
    else
        flags |= TWL4030_BBSEL_2V5;

    if (uamp >= 1000)
        flags |= TWL4030_BBISEL_1000uA;
    else if (uamp >= 500)
        flags |= TWL4030_BBISEL_500uA;
    else if (uamp >= 150)
        flags |= TWL4030_BBISEL_150uA;
    else
        flags |= TWL4030_BBISEL_25uA;

    ret = twl4030_clear_set(TWL4030_MODULE_PM_RECEIVER,
                TWL4030_BBSEL_MASK | TWL4030_BBISEL_MASK,
                flags,
                TWL4030_BB_CFG);

    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 void twl4030_bci_usb_work(struct work_struct *data)
{
    struct twl4030_bci *bci = container_of(data, struct twl4030_bci, work);

    switch (bci->event) {
    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;
    }
}

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, usb_nb);

    dev_dbg(bci->dev, "OTG notify %lu\n", val);

    bci->event = val;
    schedule_work(&bci->work);

    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;
    struct twl4030_bci_platform_data *pdata = pdev->dev.platform_data;
    int ret;
    u32 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;

    bci->usb_reg = regulator_get(bci->dev, "bci3v1");

    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, IRQF_ONESHOT, 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, IRQF_ONESHOT, 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;
    }

    INIT_WORK(&bci->work, twl4030_bci_usb_work);

    bci->transceiver = usb_get_phy(USB_PHY_TYPE_USB2);
    if (!IS_ERR_OR_NULL(bci->transceiver)) {
        bci->usb_nb.notifier_call = twl4030_bci_usb_ncb;
        usb_register_notifier(bci->transceiver, &bci->usb_nb);
    }

    /* Enable interrupts now. */
    reg = ~(u32)(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 = ~(u32)(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);
    twl4030_charger_enable_backup(pdata->bb_uvolt,
                      pdata->bb_uamp);

    return 0;

fail_unmask_interrupts:
    if (!IS_ERR_OR_NULL(bci->transceiver)) {
        usb_unregister_notifier(bci->transceiver, &bci->usb_nb);
        usb_put_phy(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);
    twl4030_charger_enable_backup(0, 0);

    /* 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 (!IS_ERR_OR_NULL(bci->transceiver)) {
        usb_unregister_notifier(bci->transceiver, &bci->usb_nb);
        usb_put_phy(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("Gražvydas Ignotas");
MODULE_DESCRIPTION("TWL4030 Battery Charger Interface driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:twl4030_bci");