// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * TWL4030/TPS65950 BCI (Battery Charger Interface) driver
 *
 * Copyright (C) 2010 Gražvydas Ignotas <notasas@gmail.com>
 *
 * based on twl4030_bci_battery.c by TI
 * Copyright (C) 2008 Texas Instruments, Inc.
 */

#include <linux/init.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/interrupt.h>
#include <linux/mfd/twl.h>
#include <linux/power_supply.h>
#include <linux/notifier.h>
#include <linux/usb/otg.h>
#include <linux/iio/consumer.h>

#define TWL4030_BCIMDEN         0x00
#define TWL4030_BCIMDKEY        0x01
#define TWL4030_BCIMSTATEC      0x02
#define TWL4030_BCIICHG         0x08
#define TWL4030_BCIVAC          0x0a
#define TWL4030_BCIVBUS         0x0c
#define TWL4030_BCIMFSTS3       0x0F
#define TWL4030_BCIMFSTS4       0x10
#define TWL4030_BCICTL1         0x23
#define TWL4030_BB_CFG          0x12
#define TWL4030_BCIIREF1        0x27
#define TWL4030_BCIIREF2        0x28
#define TWL4030_BCIMFKEY        0x11
#define TWL4030_BCIMFEN3        0x14
#define TWL4030_BCIMFTH8        0x1d
#define TWL4030_BCIMFTH9        0x1e
#define TWL4030_BCIWDKEY        0x21

#define TWL4030_BCIMFSTS1       0x01

#define TWL4030_BCIAUTOWEN      BIT(5)
#define TWL4030_CONFIG_DONE     BIT(4)
#define TWL4030_CVENAC          BIT(2)
#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

#define TWL4030_BATSTSPCHG      BIT(2)
#define TWL4030_BATSTSMCHG      BIT(6)

/* 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

/*
 * If AC (Accessory Charger) voltage exceeds 4.5V (MADC 11)
 * then AC is available.
 */
static inline int ac_available(struct iio_channel *channel_vac)
{
        int val, err;

        if (!channel_vac)
                return 0;

        err = iio_read_channel_processed(channel_vac, &val);
        if (err < 0)
                return 0;
        return val > 4500;
}

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;
        int                     usb_enabled;

        /*
         * ichg_* and *_cur values in uA. If any are 'large', we set
         * CGAIN to '1' which doubles the range for half the
         * precision.
         */
        unsigned int            ichg_eoc, ichg_lo, ichg_hi;
        unsigned int            usb_cur, ac_cur;
        struct iio_channel      *channel_vac;
        bool                    ac_is_active;
        int                     usb_mode, ac_mode; /* charging mode requested */
#define CHARGE_OFF      0
#define CHARGE_AUTO     1
#define CHARGE_LINEAR   2

        /* When setting the USB current we slowly increase the
         * requested current until target is reached or the voltage
         * drops below 4.75V.  In the latter case we step back one
         * step.
         */
        unsigned int            usb_cur_target;
        struct delayed_work     current_worker;
#define USB_CUR_STEP    20000   /* 20mA at a time */
#define USB_MIN_VOLT    4750000 /* 4.75V */
#define USB_CUR_DELAY   msecs_to_jiffies(100)
#define USB_MAX_CURRENT 1700000 /* TWL4030 caps at 1.7A */

        unsigned long           event;
};

/* strings for 'usb_mode' values */
static const char *modes[] = { "off", "auto", "continuous" };

/*
 * 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(TWL_MODULE_MAIN_CHARGE, val, reg);
}

static int twl4030_clear_set_boot_bci(u8 clear, u8 set)
{
        return twl4030_clear_set(TWL_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;
}

/*
 * 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 * 1000
 * CGAIN == 1: (val * 1.6618 - 0.85 * 1000) * 2
 */
/*
 * convert twl register value for currents into uA
 */
static int regval2ua(int regval, bool cgain)
{
        if (cgain)
                return (regval * 16618 - 8500 * 1000) / 5;
        else
                return (regval * 16618 - 8500 * 1000) / 10;
}

/*
 * convert uA currents into twl register value
 */
static int ua2regval(int ua, bool cgain)
{
        int ret;
        if (cgain)
                ua /= 2;
        ret = (ua * 10 + 8500 * 1000) / 16618;
        /* rounding problems */
        if (ret < 512)
                ret = 512;
        return ret;
}

static int twl4030_charger_update_current(struct twl4030_bci *bci)
{
        int status;
        int cur;
        unsigned reg, cur_reg;
        u8 bcictl1, oldreg, fullreg;
        bool cgain = false;
        u8 boot_bci;

        /*
         * If AC (Accessory Charger) voltage exceeds 4.5V (MADC 11)
         * and AC is enabled, set current for 'ac'
         */
        if (ac_available(bci->channel_vac)) {
                cur = bci->ac_cur;
                bci->ac_is_active = true;
        } else {
                cur = bci->usb_cur;
                bci->ac_is_active = false;
                if (cur > bci->usb_cur_target) {
                        cur = bci->usb_cur_target;
                        bci->usb_cur = cur;
                }
                if (cur < bci->usb_cur_target)
                        schedule_delayed_work(&bci->current_worker, USB_CUR_DELAY);
        }

        /* First, check thresholds and see if cgain is needed */
        if (bci->ichg_eoc >= 200000)
                cgain = true;
        if (bci->ichg_lo >= 400000)
                cgain = true;
        if (bci->ichg_hi >= 820000)
                cgain = true;
        if (cur > 852000)
                cgain = true;

        status = twl4030_bci_read(TWL4030_BCICTL1, &bcictl1);
        if (status < 0)
                return status;
        if (twl_i2c_read_u8(TWL_MODULE_PM_MASTER, &boot_bci,
                            TWL4030_PM_MASTER_BOOT_BCI) < 0)
                boot_bci = 0;
        boot_bci &= 7;

        if ((!!cgain) != !!(bcictl1 & TWL4030_CGAIN))
                /* Need to turn for charging while we change the
                 * CGAIN bit.  Leave it off while everything is
                 * updated.
                 */
                twl4030_clear_set_boot_bci(boot_bci, 0);

        /*
         * For ichg_eoc, the hardware only supports reg values matching
         * 100XXXX000, and requires the XXXX be stored in the high nibble
         * of TWL4030_BCIMFTH8.
         */
        reg = ua2regval(bci->ichg_eoc, cgain);
        if (reg > 0x278)
                reg = 0x278;
        if (reg < 0x200)
                reg = 0x200;
        reg = (reg >> 3) & 0xf;
        fullreg = reg << 4;

        /*
         * For ichg_lo, reg value must match 10XXXX0000.
         * XXXX is stored in low nibble of TWL4030_BCIMFTH8.
         */
        reg = ua2regval(bci->ichg_lo, cgain);
        if (reg > 0x2F0)
                reg = 0x2F0;
        if (reg < 0x200)
                reg = 0x200;
        reg = (reg >> 4) & 0xf;
        fullreg |= reg;

        /* ichg_eoc and ichg_lo live in same register */
        status = twl4030_bci_read(TWL4030_BCIMFTH8, &oldreg);
        if (status < 0)
                return status;
        if (oldreg != fullreg) {
                status = twl_i2c_write_u8(TWL_MODULE_MAIN_CHARGE, 0xF4,
                                          TWL4030_BCIMFKEY);
                if (status < 0)
                        return status;
                twl_i2c_write_u8(TWL_MODULE_MAIN_CHARGE,
                                 fullreg, TWL4030_BCIMFTH8);
        }

        /* ichg_hi threshold must be 1XXXX01100 (I think) */
        reg = ua2regval(bci->ichg_hi, cgain);
        if (reg > 0x3E0)
                reg = 0x3E0;
        if (reg < 0x200)
                reg = 0x200;
        fullreg = (reg >> 5) & 0xF;
        fullreg <<= 4;
        status = twl4030_bci_read(TWL4030_BCIMFTH9, &oldreg);
        if (status < 0)
                return status;
        if ((oldreg & 0xF0) != fullreg) {
                fullreg |= (oldreg & 0x0F);
                status = twl_i2c_write_u8(TWL_MODULE_MAIN_CHARGE, 0xE7,
                                          TWL4030_BCIMFKEY);
                if (status < 0)
                        return status;
                twl_i2c_write_u8(TWL_MODULE_MAIN_CHARGE,
                                 fullreg, TWL4030_BCIMFTH9);
        }

        /*
         * And finally, set the current.  This is stored in
         * two registers.
         */
        reg = ua2regval(cur, cgain);
        /* we have only 10 bits */
        if (reg > 0x3ff)
                reg = 0x3ff;
        status = twl4030_bci_read(TWL4030_BCIIREF1, &oldreg);
        if (status < 0)
                return status;
        cur_reg = oldreg;
        status = twl4030_bci_read(TWL4030_BCIIREF2, &oldreg);
        if (status < 0)
                return status;
        cur_reg |= oldreg << 8;
        if (reg != cur_reg) {
                /* disable write protection for one write access for
                 * BCIIREF */
                status = twl_i2c_write_u8(TWL_MODULE_MAIN_CHARGE, 0xE7,
                                          TWL4030_BCIMFKEY);
                if (status < 0)
                        return status;
                status = twl_i2c_write_u8(TWL_MODULE_MAIN_CHARGE,
                                          (reg & 0x100) ? 3 : 2,
                                          TWL4030_BCIIREF2);
                if (status < 0)
                        return status;
                /* disable write protection for one write access for
                 * BCIIREF */
                status = twl_i2c_write_u8(TWL_MODULE_MAIN_CHARGE, 0xE7,
                                          TWL4030_BCIMFKEY);
                if (status < 0)
                        return status;
                status = twl_i2c_write_u8(TWL_MODULE_MAIN_CHARGE,
                                          reg & 0xff,
                                          TWL4030_BCIIREF1);
        }
        if ((!!cgain) != !!(bcictl1 & TWL4030_CGAIN)) {
                /* Flip CGAIN and re-enable charging */
                bcictl1 ^= TWL4030_CGAIN;
                twl_i2c_write_u8(TWL_MODULE_MAIN_CHARGE,
                                 bcictl1, TWL4030_BCICTL1);
                twl4030_clear_set_boot_bci(0, boot_bci);
        }
        return 0;
}

static int twl4030_charger_get_current(void);

static void twl4030_current_worker(struct work_struct *data)
{
        int v, curr;
        int res;
        struct twl4030_bci *bci = container_of(data, struct twl4030_bci,
                                               current_worker.work);

        res = twl4030bci_read_adc_val(TWL4030_BCIVBUS);
        if (res < 0)
                v = 0;
        else
                /* BCIVBUS uses ADCIN8, 7/1023 V/step */
                v = res * 6843;
        curr = twl4030_charger_get_current();

        dev_dbg(bci->dev, "v=%d cur=%d limit=%d target=%d\n", v, curr,
                bci->usb_cur, bci->usb_cur_target);

        if (v < USB_MIN_VOLT) {
                /* Back up and stop adjusting. */
                if (bci->usb_cur >= USB_CUR_STEP)
                        bci->usb_cur -= USB_CUR_STEP;
                bci->usb_cur_target = bci->usb_cur;
        } else if (bci->usb_cur >= bci->usb_cur_target ||
                   bci->usb_cur + USB_CUR_STEP > USB_MAX_CURRENT) {
                /* Reached target and voltage is OK - stop */
                return;
        } else {
                bci->usb_cur += USB_CUR_STEP;
                schedule_delayed_work(&bci->current_worker, USB_CUR_DELAY);
        }
        twl4030_charger_update_current(bci);
}

/*
 * Enable/Disable USB Charge functionality.
 */
static int twl4030_charger_enable_usb(struct twl4030_bci *bci, bool enable)
{
        int ret;
        u32 reg;

        if (bci->usb_mode == CHARGE_OFF)
                enable = false;
        if (enable && !IS_ERR_OR_NULL(bci->transceiver)) {

                twl4030_charger_update_current(bci);

                /* Need to keep phy powered */
                if (!bci->usb_enabled) {
                        pm_runtime_get_sync(bci->transceiver->dev);
                        bci->usb_enabled = 1;
                }

                if (bci->usb_mode == CHARGE_AUTO) {
                        /* 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(bci->dev,
                                        "failed to unmask interrupts: %d\n",
                                        ret);
                                return ret;
                        }
                        /* forcing the field BCIAUTOUSB (BOOT_BCI[1]) to 1 */
                        ret = twl4030_clear_set_boot_bci(0, TWL4030_BCIAUTOUSB);
                }

                /* forcing USBFASTMCHG(BCIMFSTS4[2]) to 1 */
                ret = twl4030_clear_set(TWL_MODULE_MAIN_CHARGE, 0,
                        TWL4030_USBFASTMCHG, TWL4030_BCIMFSTS4);
                if (bci->usb_mode == CHARGE_LINEAR) {
                        /* Enable interrupts now. */
                        reg = ~(u32)(TWL4030_ICHGLOW | TWL4030_TBATOR2 |
                                        TWL4030_TBATOR1 | TWL4030_BATSTS);
                        ret = twl_i2c_write_u8(TWL4030_MODULE_INTERRUPTS, reg,
                                       TWL4030_INTERRUPTS_BCIIMR1A);
                        if (ret < 0) {
                                dev_err(bci->dev,
                                        "failed to unmask interrupts: %d\n",
                                        ret);
                                return ret;
                        }
                        twl4030_clear_set_boot_bci(TWL4030_BCIAUTOAC|TWL4030_CVENAC, 0);
                        /* Watch dog key: WOVF acknowledge */
                        ret = twl_i2c_write_u8(TWL_MODULE_MAIN_CHARGE, 0x33,
                                               TWL4030_BCIWDKEY);
                        /* 0x24 + EKEY6: off mode */
                        ret = twl_i2c_write_u8(TWL_MODULE_MAIN_CHARGE, 0x2a,
                                               TWL4030_BCIMDKEY);
                        /* EKEY2: Linear charge: USB path */
                        ret = twl_i2c_write_u8(TWL_MODULE_MAIN_CHARGE, 0x26,
                                               TWL4030_BCIMDKEY);
                        /* WDKEY5: stop watchdog count */
                        ret = twl_i2c_write_u8(TWL_MODULE_MAIN_CHARGE, 0xf3,
                                               TWL4030_BCIWDKEY);
                        /* enable MFEN3 access */
                        ret = twl_i2c_write_u8(TWL_MODULE_MAIN_CHARGE, 0x9c,
                                               TWL4030_BCIMFKEY);
                         /* ICHGEOCEN - end-of-charge monitor (current < 80mA)
                          *                      (charging continues)
                          * ICHGLOWEN - current level monitor (charge continues)
                          * don't monitor over-current or heat save
                          */
                        ret = twl_i2c_write_u8(TWL_MODULE_MAIN_CHARGE, 0xf0,
                                               TWL4030_BCIMFEN3);
                }
        } else {
                ret = twl4030_clear_set_boot_bci(TWL4030_BCIAUTOUSB, 0);
                ret |= twl_i2c_write_u8(TWL_MODULE_MAIN_CHARGE, 0x2a,
                                        TWL4030_BCIMDKEY);
                if (bci->usb_enabled) {
                        pm_runtime_put_autosuspend(bci->transceiver->dev);
                        bci->usb_enabled = 0;
                }
                bci->usb_cur = 0;
        }

        return ret;
}

/*
 * Enable/Disable AC Charge funtionality.
 */
static int twl4030_charger_enable_ac(struct twl4030_bci *bci, bool enable)
{
        int ret;

        if (bci->ac_mode == CHARGE_OFF)
                enable = false;

        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(TWL_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(TWL_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");
        /* reset current on each 'plug' event */
        bci->ac_cur = 500000;
        twl4030_charger_update_current(bci);
        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);
        }
        twl4030_charger_update_current(bci);

        /* 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);

        /* reset current on each 'plug' event */
        if (allow_usb)
                bci->usb_cur_target = 500000;
        else
                bci->usb_cur_target = 100000;

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

        return NOTIFY_OK;
}

/*
 * sysfs charger enabled store
 */
static ssize_t
twl4030_bci_mode_store(struct device *dev, struct device_attribute *attr,
                          const char *buf, size_t n)
{
        struct twl4030_bci *bci = dev_get_drvdata(dev->parent);
        int mode;
        int status;

        mode = sysfs_match_string(modes, buf);
        if (mode < 0)
                return mode;

        if (dev == &bci->ac->dev) {
                if (mode == 2)
                        return -EINVAL;
                twl4030_charger_enable_ac(bci, false);
                bci->ac_mode = mode;
                status = twl4030_charger_enable_ac(bci, true);
        } else {
                twl4030_charger_enable_usb(bci, false);
                bci->usb_mode = mode;
                status = twl4030_charger_enable_usb(bci, true);
        }
        return (status == 0) ? n : status;
}

/*
 * sysfs charger enabled show
 */
static ssize_t
twl4030_bci_mode_show(struct device *dev,
                             struct device_attribute *attr, char *buf)
{
        struct twl4030_bci *bci = dev_get_drvdata(dev->parent);
        int len = 0;
        int i;
        int mode = bci->usb_mode;

        if (dev == &bci->ac->dev)
                mode = bci->ac_mode;

        for (i = 0; i < ARRAY_SIZE(modes); i++)
                if (mode == i)
                        len += sysfs_emit_at(buf, len, "[%s] ", modes[i]);
                else
                        len += sysfs_emit_at(buf, len, "%s ", modes[i]);
        buf[len-1] = '\n';
        return len;
}
static DEVICE_ATTR(mode, 0644, twl4030_bci_mode_show,
                   twl4030_bci_mode_store);

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;

        return regval2ua(curr, bcictl1 & TWL4030_CGAIN);
}

/*
 * 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) {
                dev_err(bci->dev, "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->desc->type == POWER_SUPPLY_TYPE_USB)
                is_charging = state & TWL4030_MSTATEC_USB;
        else
                is_charging = state & TWL4030_MSTATEC_AC;
        if (!is_charging) {
                u8 s;
                ret = twl4030_bci_read(TWL4030_BCIMDEN, &s);
                if (ret < 0)
                        return ret;
                if (psy->desc->type == POWER_SUPPLY_TYPE_USB)
                        is_charging = s & 1;
                else
                        is_charging = s & 2;
                if (is_charging)
                        /* A little white lie */
                        state = TWL4030_MSTATEC_QUICK1;
        }

        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->desc->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;
        case POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT:
                val->intval = -1;
                if (psy->desc->type != POWER_SUPPLY_TYPE_USB) {
                        if (!bci->ac_is_active)
                                val->intval = bci->ac_cur;
                } else {
                        if (bci->ac_is_active)
                                val->intval = bci->usb_cur_target;
                }
                if (val->intval < 0) {
                        u8 bcictl1;

                        val->intval = twl4030bci_read_adc_val(TWL4030_BCIIREF1);
                        if (val->intval < 0)
                                return val->intval;
                        ret = twl4030_bci_read(TWL4030_BCICTL1, &bcictl1);
                        if (ret < 0)
                                return ret;
                        val->intval = regval2ua(val->intval, bcictl1 &
                                                        TWL4030_CGAIN);
                }
                break;
        default:
                return -EINVAL;
        }

        return 0;
}

static int twl4030_bci_set_property(struct power_supply *psy,
                                    enum power_supply_property psp,
                                    const union power_supply_propval *val)
{
        struct twl4030_bci *bci = dev_get_drvdata(psy->dev.parent);

        switch (psp) {
        case POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT:
                if (psy->desc->type == POWER_SUPPLY_TYPE_USB)
                        bci->usb_cur_target = val->intval;
                else
                        bci->ac_cur = val->intval;
                twl4030_charger_update_current(bci);
                break;
        default:
                return -EINVAL;
        }

        return 0;
}

static int twl4030_bci_property_is_writeable(struct power_supply *psy,
                                      enum power_supply_property psp)
{
        switch (psp) {
        case POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT:
                return true;
        default:
                return false;
        }
}

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,
        POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT,
};

#ifdef CONFIG_OF
static const struct twl4030_bci_platform_data *
twl4030_bci_parse_dt(struct device *dev)
{
        struct device_node *np = dev->of_node;
        struct twl4030_bci_platform_data *pdata;
        u32 num;

        if (!np)
                return NULL;
        pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
        if (!pdata)
                return pdata;

        if (of_property_read_u32(np, "ti,bb-uvolt", &num) == 0)
                pdata->bb_uvolt = num;
        if (of_property_read_u32(np, "ti,bb-uamp", &num) == 0)
                pdata->bb_uamp = num;
        return pdata;
}
#else
static inline const struct twl4030_bci_platform_data *
twl4030_bci_parse_dt(struct device *dev)
{
        return NULL;
}
#endif

static const struct power_supply_desc twl4030_bci_ac_desc = {
        .name           = "twl4030_ac",
        .type           = POWER_SUPPLY_TYPE_MAINS,
        .properties     = twl4030_charger_props,
        .num_properties = ARRAY_SIZE(twl4030_charger_props),
        .get_property   = twl4030_bci_get_property,
        .set_property   = twl4030_bci_set_property,
        .property_is_writeable  = twl4030_bci_property_is_writeable,
};

static const struct power_supply_desc twl4030_bci_usb_desc = {
        .name           = "twl4030_usb",
        .type           = POWER_SUPPLY_TYPE_USB,
        .properties     = twl4030_charger_props,
        .num_properties = ARRAY_SIZE(twl4030_charger_props),
        .get_property   = twl4030_bci_get_property,
        .set_property   = twl4030_bci_set_property,
        .property_is_writeable  = twl4030_bci_property_is_writeable,
};

static int twl4030_bci_probe(struct platform_device *pdev)
{
        struct twl4030_bci *bci;
        const struct twl4030_bci_platform_data *pdata = pdev->dev.platform_data;
        int ret;
        u32 reg;

        bci = devm_kzalloc(&pdev->dev, sizeof(*bci), GFP_KERNEL);
        if (bci == NULL)
                return -ENOMEM;

        if (!pdata)
                pdata = twl4030_bci_parse_dt(&pdev->dev);

        bci->ichg_eoc = 80100; /* Stop charging when current drops to here */
        bci->ichg_lo = 241000; /* Low threshold */
        bci->ichg_hi = 500000; /* High threshold */
        bci->ac_cur = 500000; /* 500mA */
        if (allow_usb)
                bci->usb_cur_target = 500000;  /* 500mA */
        else
                bci->usb_cur_target = 100000;  /* 100mA */
        bci->usb_mode = CHARGE_AUTO;
        bci->ac_mode = CHARGE_AUTO;

        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);

        INIT_WORK(&bci->work, twl4030_bci_usb_work);
        INIT_DELAYED_WORK(&bci->current_worker, twl4030_current_worker);

        bci->channel_vac = devm_iio_channel_get(&pdev->dev, "vac");
        if (IS_ERR(bci->channel_vac)) {
                ret = PTR_ERR(bci->channel_vac);
                if (ret == -EPROBE_DEFER)
                        return ret;     /* iio not ready */
                dev_warn(&pdev->dev, "could not request vac iio channel (%d)",
                        ret);
                bci->channel_vac = NULL;
        }

        if (bci->dev->of_node) {
                struct device_node *phynode;

                phynode = of_get_compatible_child(bci->dev->of_node->parent,
                                                  "ti,twl4030-usb");
                if (phynode) {
                        bci->usb_nb.notifier_call = twl4030_bci_usb_ncb;
                        bci->transceiver = devm_usb_get_phy_by_node(
                                bci->dev, phynode, &bci->usb_nb);
                        of_node_put(phynode);
                        if (IS_ERR(bci->transceiver)) {
                                ret = PTR_ERR(bci->transceiver);
                                if (ret == -EPROBE_DEFER)
                                        return ret;     /* phy not ready */
                                dev_warn(&pdev->dev, "could not request transceiver (%d)",
                                        ret);
                                bci->transceiver = NULL;
                        }
                }
        }

        bci->ac = devm_power_supply_register(&pdev->dev, &twl4030_bci_ac_desc,
                                             NULL);
        if (IS_ERR(bci->ac)) {
                ret = PTR_ERR(bci->ac);
                dev_err(&pdev->dev, "failed to register ac: %d\n", ret);
                return ret;
        }

        bci->usb = devm_power_supply_register(&pdev->dev, &twl4030_bci_usb_desc,
                                              NULL);
        if (IS_ERR(bci->usb)) {
                ret = PTR_ERR(bci->usb);
                dev_err(&pdev->dev, "failed to register usb: %d\n", ret);
                return ret;
        }

        ret = devm_request_threaded_irq(&pdev->dev, 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);
                return ret;
        }

        ret = devm_request_threaded_irq(&pdev->dev, 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);
                return ret;
        }

        /* 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);
                return ret;
        }

        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_update_current(bci);
        if (device_create_file(&bci->usb->dev, &dev_attr_mode))
                dev_warn(&pdev->dev, "could not create sysfs file\n");
        if (device_create_file(&bci->ac->dev, &dev_attr_mode))
                dev_warn(&pdev->dev, "could not create sysfs file\n");

        twl4030_charger_enable_ac(bci, true);
        if (!IS_ERR_OR_NULL(bci->transceiver))
                twl4030_bci_usb_ncb(&bci->usb_nb,
                                    bci->transceiver->last_event,
                                    NULL);
        else
                twl4030_charger_enable_usb(bci, false);
        if (pdata)
                twl4030_charger_enable_backup(pdata->bb_uvolt,
                                              pdata->bb_uamp);
        else
                twl4030_charger_enable_backup(0, 0);

        return 0;
}

static void twl4030_bci_remove(struct platform_device *pdev)
{
        struct twl4030_bci *bci = platform_get_drvdata(pdev);

        twl4030_charger_enable_ac(bci, false);
        twl4030_charger_enable_usb(bci, false);
        twl4030_charger_enable_backup(0, 0);

        device_remove_file(&bci->usb->dev, &dev_attr_mode);
        device_remove_file(&bci->ac->dev, &dev_attr_mode);
        /* mask interrupts */
        twl_i2c_write_u8(TWL4030_MODULE_INTERRUPTS, 0xff,
                         TWL4030_INTERRUPTS_BCIIMR1A);
        twl_i2c_write_u8(TWL4030_MODULE_INTERRUPTS, 0xff,
                         TWL4030_INTERRUPTS_BCIIMR2A);
}

static const struct of_device_id twl_bci_of_match[] __maybe_unused = {
        {.compatible = "ti,twl4030-bci", },
        { }
};
MODULE_DEVICE_TABLE(of, twl_bci_of_match);

static struct platform_driver twl4030_bci_driver = {
        .probe = twl4030_bci_probe,
        .remove = twl4030_bci_remove,
        .driver = {
                .name   = "twl4030_bci",
                .of_match_table = of_match_ptr(twl_bci_of_match),
        },
};
module_platform_driver(twl4030_bci_driver);

MODULE_AUTHOR("Gražvydas Ignotas");
MODULE_DESCRIPTION("TWL4030 Battery Charger Interface driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:twl4030_bci");