/*
 * MPU3050 gyroscope driver
 *
 * Copyright (C) 2016 Linaro Ltd.
 * Author: Linus Walleij <linus.walleij@linaro.org>
 *
 * Based on the input subsystem driver, Copyright (C) 2011 Wistron Co.Ltd
 * Joseph Lai <joseph_lai@wistron.com> and trimmed down by
 * Alan Cox <alan@linux.intel.com> in turn based on bma023.c.
 * Device behaviour based on a misc driver posted by Nathan Royer in 2011.
 *
 * TODO: add support for setting up the low pass 3dB frequency.
 */

#include <linux/bitops.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/iio/buffer.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/trigger.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/iio/triggered_buffer.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/pm_runtime.h>
#include <linux/random.h>
#include <linux/slab.h>

#include "mpu3050.h"

#define MPU3050_CHIP_ID         0x69

/*
 * Register map: anything suffixed *_H is a big-endian high byte and always
 * followed by the corresponding low byte (*_L) even though these are not
 * explicitly included in the register definitions.
 */
#define MPU3050_CHIP_ID_REG     0x00
#define MPU3050_PRODUCT_ID_REG  0x01
#define MPU3050_XG_OFFS_TC      0x05
#define MPU3050_YG_OFFS_TC      0x08
#define MPU3050_ZG_OFFS_TC      0x0B
#define MPU3050_X_OFFS_USR_H    0x0C
#define MPU3050_Y_OFFS_USR_H    0x0E
#define MPU3050_Z_OFFS_USR_H    0x10
#define MPU3050_FIFO_EN         0x12
#define MPU3050_AUX_VDDIO       0x13
#define MPU3050_SLV_ADDR        0x14
#define MPU3050_SMPLRT_DIV      0x15
#define MPU3050_DLPF_FS_SYNC    0x16
#define MPU3050_INT_CFG         0x17
#define MPU3050_AUX_ADDR        0x18
#define MPU3050_INT_STATUS      0x1A
#define MPU3050_TEMP_H          0x1B
#define MPU3050_XOUT_H          0x1D
#define MPU3050_YOUT_H          0x1F
#define MPU3050_ZOUT_H          0x21
#define MPU3050_DMP_CFG1        0x35
#define MPU3050_DMP_CFG2        0x36
#define MPU3050_BANK_SEL        0x37
#define MPU3050_MEM_START_ADDR  0x38
#define MPU3050_MEM_R_W         0x39
#define MPU3050_FIFO_COUNT_H    0x3A
#define MPU3050_FIFO_R          0x3C
#define MPU3050_USR_CTRL        0x3D
#define MPU3050_PWR_MGM         0x3E

/* MPU memory bank read options */
#define MPU3050_MEM_PRFTCH      BIT(5)
#define MPU3050_MEM_USER_BANK   BIT(4)
/* Bits 8-11 select memory bank */
#define MPU3050_MEM_RAM_BANK_0  0
#define MPU3050_MEM_RAM_BANK_1  1
#define MPU3050_MEM_RAM_BANK_2  2
#define MPU3050_MEM_RAM_BANK_3  3
#define MPU3050_MEM_OTP_BANK_0  4

#define MPU3050_AXIS_REGS(axis) (MPU3050_XOUT_H + (axis * 2))

/* Register bits */

/* FIFO Enable */
#define MPU3050_FIFO_EN_FOOTER          BIT(0)
#define MPU3050_FIFO_EN_AUX_ZOUT        BIT(1)
#define MPU3050_FIFO_EN_AUX_YOUT        BIT(2)
#define MPU3050_FIFO_EN_AUX_XOUT        BIT(3)
#define MPU3050_FIFO_EN_GYRO_ZOUT       BIT(4)
#define MPU3050_FIFO_EN_GYRO_YOUT       BIT(5)
#define MPU3050_FIFO_EN_GYRO_XOUT       BIT(6)
#define MPU3050_FIFO_EN_TEMP_OUT        BIT(7)

/*
 * Digital Low Pass filter (DLPF)
 * Full Scale (FS)
 * and Synchronization
 */
#define MPU3050_EXT_SYNC_NONE           0x00
#define MPU3050_EXT_SYNC_TEMP           0x20
#define MPU3050_EXT_SYNC_GYROX          0x40
#define MPU3050_EXT_SYNC_GYROY          0x60
#define MPU3050_EXT_SYNC_GYROZ          0x80
#define MPU3050_EXT_SYNC_ACCELX 0xA0
#define MPU3050_EXT_SYNC_ACCELY 0xC0
#define MPU3050_EXT_SYNC_ACCELZ 0xE0
#define MPU3050_EXT_SYNC_MASK           0xE0
#define MPU3050_EXT_SYNC_SHIFT          5

#define MPU3050_FS_250DPS               0x00
#define MPU3050_FS_500DPS               0x08
#define MPU3050_FS_1000DPS              0x10
#define MPU3050_FS_2000DPS              0x18
#define MPU3050_FS_MASK                 0x18
#define MPU3050_FS_SHIFT                3

#define MPU3050_DLPF_CFG_256HZ_NOLPF2   0x00
#define MPU3050_DLPF_CFG_188HZ          0x01
#define MPU3050_DLPF_CFG_98HZ           0x02
#define MPU3050_DLPF_CFG_42HZ           0x03
#define MPU3050_DLPF_CFG_20HZ           0x04
#define MPU3050_DLPF_CFG_10HZ           0x05
#define MPU3050_DLPF_CFG_5HZ            0x06
#define MPU3050_DLPF_CFG_2100HZ_NOLPF   0x07
#define MPU3050_DLPF_CFG_MASK           0x07
#define MPU3050_DLPF_CFG_SHIFT          0

/* Interrupt config */
#define MPU3050_INT_RAW_RDY_EN          BIT(0)
#define MPU3050_INT_DMP_DONE_EN         BIT(1)
#define MPU3050_INT_MPU_RDY_EN          BIT(2)
#define MPU3050_INT_ANYRD_2CLEAR        BIT(4)
#define MPU3050_INT_LATCH_EN            BIT(5)
#define MPU3050_INT_OPEN                BIT(6)
#define MPU3050_INT_ACTL                BIT(7)
/* Interrupt status */
#define MPU3050_INT_STATUS_RAW_RDY      BIT(0)
#define MPU3050_INT_STATUS_DMP_DONE     BIT(1)
#define MPU3050_INT_STATUS_MPU_RDY      BIT(2)
#define MPU3050_INT_STATUS_FIFO_OVFLW   BIT(7)
/* USR_CTRL */
#define MPU3050_USR_CTRL_FIFO_EN        BIT(6)
#define MPU3050_USR_CTRL_AUX_IF_EN      BIT(5)
#define MPU3050_USR_CTRL_AUX_IF_RST     BIT(3)
#define MPU3050_USR_CTRL_FIFO_RST       BIT(1)
#define MPU3050_USR_CTRL_GYRO_RST       BIT(0)
/* PWR_MGM */
#define MPU3050_PWR_MGM_PLL_X           0x01
#define MPU3050_PWR_MGM_PLL_Y           0x02
#define MPU3050_PWR_MGM_PLL_Z           0x03
#define MPU3050_PWR_MGM_CLKSEL_MASK     0x07
#define MPU3050_PWR_MGM_STBY_ZG         BIT(3)
#define MPU3050_PWR_MGM_STBY_YG         BIT(4)
#define MPU3050_PWR_MGM_STBY_XG         BIT(5)
#define MPU3050_PWR_MGM_SLEEP           BIT(6)
#define MPU3050_PWR_MGM_RESET           BIT(7)
#define MPU3050_PWR_MGM_MASK            0xff

/*
 * Fullscale precision is (for finest precision) +/- 250 deg/s, so the full
 * scale is actually 500 deg/s. All 16 bits are then used to cover this scale,
 * in two's complement.
 */
static unsigned int mpu3050_fs_precision[] = {
        IIO_DEGREE_TO_RAD(250),
        IIO_DEGREE_TO_RAD(500),
        IIO_DEGREE_TO_RAD(1000),
        IIO_DEGREE_TO_RAD(2000)
};

/*
 * Regulator names
 */
static const char mpu3050_reg_vdd[] = "vdd";
static const char mpu3050_reg_vlogic[] = "vlogic";

static unsigned int mpu3050_get_freq(struct mpu3050 *mpu3050)
{
        unsigned int freq;

        if (mpu3050->lpf == MPU3050_DLPF_CFG_256HZ_NOLPF2)
                freq = 8000;
        else
                freq = 1000;
        freq /= (mpu3050->divisor + 1);

        return freq;
}

static int mpu3050_start_sampling(struct mpu3050 *mpu3050)
{
        __be16 raw_val[3];
        int ret;
        int i;

        /* Reset */
        ret = regmap_update_bits(mpu3050->map, MPU3050_PWR_MGM,
                                 MPU3050_PWR_MGM_RESET, MPU3050_PWR_MGM_RESET);
        if (ret)
                return ret;

        /* Turn on the Z-axis PLL */
        ret = regmap_update_bits(mpu3050->map, MPU3050_PWR_MGM,
                                 MPU3050_PWR_MGM_CLKSEL_MASK,
                                 MPU3050_PWR_MGM_PLL_Z);
        if (ret)
                return ret;

        /* Write calibration offset registers */
        for (i = 0; i < 3; i++)
                raw_val[i] = cpu_to_be16(mpu3050->calibration[i]);

        ret = regmap_bulk_write(mpu3050->map, MPU3050_X_OFFS_USR_H, raw_val,
                                sizeof(raw_val));
        if (ret)
                return ret;

        /* Set low pass filter (sample rate), sync and full scale */
        ret = regmap_write(mpu3050->map, MPU3050_DLPF_FS_SYNC,
                           MPU3050_EXT_SYNC_NONE << MPU3050_EXT_SYNC_SHIFT |
                           mpu3050->fullscale << MPU3050_FS_SHIFT |
                           mpu3050->lpf << MPU3050_DLPF_CFG_SHIFT);
        if (ret)
                return ret;

        /* Set up sampling frequency */
        ret = regmap_write(mpu3050->map, MPU3050_SMPLRT_DIV, mpu3050->divisor);
        if (ret)
                return ret;

        /*
         * Max 50 ms start-up time after setting DLPF_FS_SYNC
         * according to the data sheet, then wait for the next sample
         * at this frequency T = 1000/f ms.
         */
        msleep(50 + 1000 / mpu3050_get_freq(mpu3050));

        return 0;
}

static int mpu3050_set_8khz_samplerate(struct mpu3050 *mpu3050)
{
        int ret;
        u8 divisor;
        enum mpu3050_lpf lpf;

        lpf = mpu3050->lpf;
        divisor = mpu3050->divisor;

        mpu3050->lpf = LPF_256_HZ_NOLPF; /* 8 kHz base frequency */
        mpu3050->divisor = 0; /* Divide by 1 */
        ret = mpu3050_start_sampling(mpu3050);

        mpu3050->lpf = lpf;
        mpu3050->divisor = divisor;

        return ret;
}

static int mpu3050_read_raw(struct iio_dev *indio_dev,
                            struct iio_chan_spec const *chan,
                            int *val, int *val2,
                            long mask)
{
        struct mpu3050 *mpu3050 = iio_priv(indio_dev);
        int ret;
        __be16 raw_val;

        switch (mask) {
        case IIO_CHAN_INFO_OFFSET:
                switch (chan->type) {
                case IIO_TEMP:
                        /* The temperature scaling is (x+23000)/280 Celsius */
                        *val = 23000;
                        return IIO_VAL_INT;
                default:
                        return -EINVAL;
                }
        case IIO_CHAN_INFO_CALIBBIAS:
                switch (chan->type) {
                case IIO_ANGL_VEL:
                        *val = mpu3050->calibration[chan->scan_index-1];
                        return IIO_VAL_INT;
                default:
                        return -EINVAL;
                }
        case IIO_CHAN_INFO_SAMP_FREQ:
                *val = mpu3050_get_freq(mpu3050);
                return IIO_VAL_INT;
        case IIO_CHAN_INFO_SCALE:
                switch (chan->type) {
                case IIO_TEMP:
                        /* Millidegrees, see about temperature scaling above */
                        *val = 1000;
                        *val2 = 280;
                        return IIO_VAL_FRACTIONAL;
                case IIO_ANGL_VEL:
                        /*
                         * Convert to the corresponding full scale in
                         * radians. All 16 bits are used with sign to
                         * span the available scale: to account for the one
                         * missing value if we multiply by 1/S16_MAX, instead
                         * multiply with 2/U16_MAX.
                         */
                        *val = mpu3050_fs_precision[mpu3050->fullscale] * 2;
                        *val2 = U16_MAX;
                        return IIO_VAL_FRACTIONAL;
                default:
                        return -EINVAL;
                }
        case IIO_CHAN_INFO_RAW:
                /* Resume device */
                pm_runtime_get_sync(mpu3050->dev);
                mutex_lock(&mpu3050->lock);

                ret = mpu3050_set_8khz_samplerate(mpu3050);
                if (ret)
                        goto out_read_raw_unlock;

                switch (chan->type) {
                case IIO_TEMP:
                        ret = regmap_bulk_read(mpu3050->map, MPU3050_TEMP_H,
                                               &raw_val, sizeof(raw_val));
                        if (ret) {
                                dev_err(mpu3050->dev,
                                        "error reading temperature\n");
                                goto out_read_raw_unlock;
                        }

                        *val = be16_to_cpu(raw_val);
                        ret = IIO_VAL_INT;

                        goto out_read_raw_unlock;
                case IIO_ANGL_VEL:
                        ret = regmap_bulk_read(mpu3050->map,
                                       MPU3050_AXIS_REGS(chan->scan_index-1),
                                       &raw_val,
                                       sizeof(raw_val));
                        if (ret) {
                                dev_err(mpu3050->dev,
                                        "error reading axis data\n");
                                goto out_read_raw_unlock;
                        }

                        *val = be16_to_cpu(raw_val);
                        ret = IIO_VAL_INT;

                        goto out_read_raw_unlock;
                default:
                        ret = -EINVAL;
                        goto out_read_raw_unlock;
                }
        default:
                break;
        }

        return -EINVAL;

out_read_raw_unlock:
        mutex_unlock(&mpu3050->lock);
        pm_runtime_mark_last_busy(mpu3050->dev);
        pm_runtime_put_autosuspend(mpu3050->dev);

        return ret;
}

static int mpu3050_write_raw(struct iio_dev *indio_dev,
                             const struct iio_chan_spec *chan,
                             int val, int val2, long mask)
{
        struct mpu3050 *mpu3050 = iio_priv(indio_dev);
        /*
         * Couldn't figure out a way to precalculate these at compile time.
         */
        unsigned int fs250 =
                DIV_ROUND_CLOSEST(mpu3050_fs_precision[0] * 1000000 * 2,
                                  U16_MAX);
        unsigned int fs500 =
                DIV_ROUND_CLOSEST(mpu3050_fs_precision[1] * 1000000 * 2,
                                  U16_MAX);
        unsigned int fs1000 =
                DIV_ROUND_CLOSEST(mpu3050_fs_precision[2] * 1000000 * 2,
                                  U16_MAX);
        unsigned int fs2000 =
                DIV_ROUND_CLOSEST(mpu3050_fs_precision[3] * 1000000 * 2,
                                  U16_MAX);

        switch (mask) {
        case IIO_CHAN_INFO_CALIBBIAS:
                if (chan->type != IIO_ANGL_VEL)
                        return -EINVAL;
                mpu3050->calibration[chan->scan_index-1] = val;
                return 0;
        case IIO_CHAN_INFO_SAMP_FREQ:
                /*
                 * The max samplerate is 8000 Hz, the minimum
                 * 1000 / 256 ~= 4 Hz
                 */
                if (val < 4 || val > 8000)
                        return -EINVAL;

                /*
                 * Above 1000 Hz we must turn off the digital low pass filter
                 * so we get a base frequency of 8kHz to the divider
                 */
                if (val > 1000) {
                        mpu3050->lpf = LPF_256_HZ_NOLPF;
                        mpu3050->divisor = DIV_ROUND_CLOSEST(8000, val) - 1;
                        return 0;
                }

                mpu3050->lpf = LPF_188_HZ;
                mpu3050->divisor = DIV_ROUND_CLOSEST(1000, val) - 1;
                return 0;
        case IIO_CHAN_INFO_SCALE:
                if (chan->type != IIO_ANGL_VEL)
                        return -EINVAL;
                /*
                 * We support +/-250, +/-500, +/-1000 and +/2000 deg/s
                 * which means we need to round to the closest radians
                 * which will be roughly +/-4.3, +/-8.7, +/-17.5, +/-35
                 * rad/s. The scale is then for the 16 bits used to cover
                 * it 2/(2^16) of that.
                 */

                /* Just too large, set the max range */
                if (val != 0) {
                        mpu3050->fullscale = FS_2000_DPS;
                        return 0;
                }

                /*
                 * Now we're dealing with fractions below zero in millirad/s
                 * do some integer interpolation and match with the closest
                 * fullscale in the table.
                 */
                if (val2 <= fs250 ||
                    val2 < ((fs500 + fs250) / 2))
                        mpu3050->fullscale = FS_250_DPS;
                else if (val2 <= fs500 ||
                         val2 < ((fs1000 + fs500) / 2))
                        mpu3050->fullscale = FS_500_DPS;
                else if (val2 <= fs1000 ||
                         val2 < ((fs2000 + fs1000) / 2))
                        mpu3050->fullscale = FS_1000_DPS;
                else
                        /* Catch-all */
                        mpu3050->fullscale = FS_2000_DPS;
                return 0;
        default:
                break;
        }

        return -EINVAL;
}

static irqreturn_t mpu3050_trigger_handler(int irq, void *p)
{
        const struct iio_poll_func *pf = p;
        struct iio_dev *indio_dev = pf->indio_dev;
        struct mpu3050 *mpu3050 = iio_priv(indio_dev);
        int ret;
        /*
         * Temperature 1*16 bits
         * Three axes 3*16 bits
         * Timestamp 64 bits (4*16 bits)
         * Sum total 8*16 bits
         */
        __be16 hw_values[8];
        s64 timestamp;
        unsigned int datums_from_fifo = 0;

        /*
         * If we're using the hardware trigger, get the precise timestamp from
         * the top half of the threaded IRQ handler. Otherwise get the
         * timestamp here so it will be close in time to the actual values
         * read from the registers.
         */
        if (iio_trigger_using_own(indio_dev))
                timestamp = mpu3050->hw_timestamp;
        else
                timestamp = iio_get_time_ns(indio_dev);

        mutex_lock(&mpu3050->lock);

        /* Using the hardware IRQ trigger? Check the buffer then. */
        if (mpu3050->hw_irq_trigger) {
                __be16 raw_fifocnt;
                u16 fifocnt;
                /* X, Y, Z + temperature */
                unsigned int bytes_per_datum = 8;
                bool fifo_overflow = false;

                ret = regmap_bulk_read(mpu3050->map,
                                       MPU3050_FIFO_COUNT_H,
                                       &raw_fifocnt,
                                       sizeof(raw_fifocnt));
                if (ret)
                        goto out_trigger_unlock;
                fifocnt = be16_to_cpu(raw_fifocnt);

                if (fifocnt == 512) {
                        dev_info(mpu3050->dev,
                                 "FIFO overflow! Emptying and resetting FIFO\n");
                        fifo_overflow = true;
                        /* Reset and enable the FIFO */
                        ret = regmap_update_bits(mpu3050->map,
                                                 MPU3050_USR_CTRL,
                                                 MPU3050_USR_CTRL_FIFO_EN |
                                                 MPU3050_USR_CTRL_FIFO_RST,
                                                 MPU3050_USR_CTRL_FIFO_EN |
                                                 MPU3050_USR_CTRL_FIFO_RST);
                        if (ret) {
                                dev_info(mpu3050->dev, "error resetting FIFO\n");
                                goto out_trigger_unlock;
                        }
                        mpu3050->pending_fifo_footer = false;
                }

                if (fifocnt)
                        dev_dbg(mpu3050->dev,
                                "%d bytes in the FIFO\n",
                                fifocnt);

                while (!fifo_overflow && fifocnt > bytes_per_datum) {
                        unsigned int toread;
                        unsigned int offset;
                        __be16 fifo_values[5];

                        /*
                         * If there is a FIFO footer in the pipe, first clear
                         * that out. This follows the complex algorithm in the
                         * datasheet that states that you may never leave the
                         * FIFO empty after the first reading: you have to
                         * always leave two footer bytes in it. The footer is
                         * in practice just two zero bytes.
                         */
                        if (mpu3050->pending_fifo_footer) {
                                toread = bytes_per_datum + 2;
                                offset = 0;
                        } else {
                                toread = bytes_per_datum;
                                offset = 1;
                                /* Put in some dummy value */
                                fifo_values[0] = 0xAAAA;
                        }

                        ret = regmap_bulk_read(mpu3050->map,
                                               MPU3050_FIFO_R,
                                               &fifo_values[offset],
                                               toread);

                        dev_dbg(mpu3050->dev,
                                "%04x %04x %04x %04x %04x\n",
                                fifo_values[0],
                                fifo_values[1],
                                fifo_values[2],
                                fifo_values[3],
                                fifo_values[4]);

                        /* Index past the footer (fifo_values[0]) and push */
                        iio_push_to_buffers_with_timestamp(indio_dev,
                                                           &fifo_values[1],
                                                           timestamp);

                        fifocnt -= toread;
                        datums_from_fifo++;
                        mpu3050->pending_fifo_footer = true;

                        /*
                         * If we're emptying the FIFO, just make sure to
                         * check if something new appeared.
                         */
                        if (fifocnt < bytes_per_datum) {
                                ret = regmap_bulk_read(mpu3050->map,
                                                       MPU3050_FIFO_COUNT_H,
                                                       &raw_fifocnt,
                                                       sizeof(raw_fifocnt));
                                if (ret)
                                        goto out_trigger_unlock;
                                fifocnt = be16_to_cpu(raw_fifocnt);
                        }

                        if (fifocnt < bytes_per_datum)
                                dev_dbg(mpu3050->dev,
                                        "%d bytes left in the FIFO\n",
                                        fifocnt);

                        /*
                         * At this point, the timestamp that triggered the
                         * hardware interrupt is no longer valid for what
                         * we are reading (the interrupt likely fired for
                         * the value on the top of the FIFO), so set the
                         * timestamp to zero and let userspace deal with it.
                         */
                        timestamp = 0;
                }
        }

        /*
         * If we picked some datums from the FIFO that's enough, else
         * fall through and just read from the current value registers.
         * This happens in two cases:
         *
         * - We are using some other trigger (external, like an HRTimer)
         *   than the sensor's own sample generator. In this case the
         *   sensor is just set to the max sampling frequency and we give
         *   the trigger a copy of the latest value every time we get here.
         *
         * - The hardware trigger is active but unused and we actually use
         *   another trigger which calls here with a frequency higher
         *   than what the device provides data. We will then just read
         *   duplicate values directly from the hardware registers.
         */
        if (datums_from_fifo) {
                dev_dbg(mpu3050->dev,
                        "read %d datums from the FIFO\n",
                        datums_from_fifo);
                goto out_trigger_unlock;
        }

        ret = regmap_bulk_read(mpu3050->map, MPU3050_TEMP_H, &hw_values,
                               sizeof(hw_values));
        if (ret) {
                dev_err(mpu3050->dev,
                        "error reading axis data\n");
                goto out_trigger_unlock;
        }

        iio_push_to_buffers_with_timestamp(indio_dev, hw_values, timestamp);

out_trigger_unlock:
        mutex_unlock(&mpu3050->lock);
        iio_trigger_notify_done(indio_dev->trig);

        return IRQ_HANDLED;
}

static int mpu3050_buffer_preenable(struct iio_dev *indio_dev)
{
        struct mpu3050 *mpu3050 = iio_priv(indio_dev);

        pm_runtime_get_sync(mpu3050->dev);

        /* Unless we have OUR trigger active, run at full speed */
        if (!mpu3050->hw_irq_trigger)
                return mpu3050_set_8khz_samplerate(mpu3050);

        return 0;
}

static int mpu3050_buffer_postdisable(struct iio_dev *indio_dev)
{
        struct mpu3050 *mpu3050 = iio_priv(indio_dev);

        pm_runtime_mark_last_busy(mpu3050->dev);
        pm_runtime_put_autosuspend(mpu3050->dev);

        return 0;
}

static const struct iio_buffer_setup_ops mpu3050_buffer_setup_ops = {
        .preenable = mpu3050_buffer_preenable,
        .postenable = iio_triggered_buffer_postenable,
        .predisable = iio_triggered_buffer_predisable,
        .postdisable = mpu3050_buffer_postdisable,
};

static const struct iio_mount_matrix *
mpu3050_get_mount_matrix(const struct iio_dev *indio_dev,
                         const struct iio_chan_spec *chan)
{
        struct mpu3050 *mpu3050 = iio_priv(indio_dev);

        return &mpu3050->orientation;
}

static const struct iio_chan_spec_ext_info mpu3050_ext_info[] = {
        IIO_MOUNT_MATRIX(IIO_SHARED_BY_TYPE, mpu3050_get_mount_matrix),
        { },
};

#define MPU3050_AXIS_CHANNEL(axis, index)                               \
        {                                                               \
                .type = IIO_ANGL_VEL,                                   \
                .modified = 1,                                          \
                .channel2 = IIO_MOD_##axis,                             \
                .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |          \
                        BIT(IIO_CHAN_INFO_CALIBBIAS),                   \
                .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),   \
                .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),\
                .ext_info = mpu3050_ext_info,                           \
                .scan_index = index,                                    \
                .scan_type = {                                          \
                        .sign = 's',                                    \
                        .realbits = 16,                                 \
                        .storagebits = 16,                              \
                        .endianness = IIO_BE,                           \
                },                                                      \
        }

static const struct iio_chan_spec mpu3050_channels[] = {
        {
                .type = IIO_TEMP,
                .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
                                      BIT(IIO_CHAN_INFO_SCALE) |
                                      BIT(IIO_CHAN_INFO_OFFSET),
                .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
                .scan_index = 0,
                .scan_type = {
                        .sign = 's',
                        .realbits = 16,
                        .storagebits = 16,
                        .endianness = IIO_BE,
                },
        },
        MPU3050_AXIS_CHANNEL(X, 1),
        MPU3050_AXIS_CHANNEL(Y, 2),
        MPU3050_AXIS_CHANNEL(Z, 3),
        IIO_CHAN_SOFT_TIMESTAMP(4),
};

/* Four channels apart from timestamp, scan mask = 0x0f */
static const unsigned long mpu3050_scan_masks[] = { 0xf, 0 };

/*
 * These are just the hardcoded factors resulting from the more elaborate
 * calculations done with fractions in the scale raw get/set functions.
 */
static IIO_CONST_ATTR(anglevel_scale_available,
                      "0.000122070 "
                      "0.000274658 "
                      "0.000518798 "
                      "0.001068115");

static struct attribute *mpu3050_attributes[] = {
        &iio_const_attr_anglevel_scale_available.dev_attr.attr,
        NULL,
};

static const struct attribute_group mpu3050_attribute_group = {
        .attrs = mpu3050_attributes,
};

static const struct iio_info mpu3050_info = {
        .driver_module = THIS_MODULE,
        .read_raw = mpu3050_read_raw,
        .write_raw = mpu3050_write_raw,
        .attrs = &mpu3050_attribute_group,
};

/**
 * mpu3050_read_mem() - read MPU-3050 internal memory
 * @mpu3050: device to read from
 * @bank: target bank
 * @addr: target address
 * @len: number of bytes
 * @buf: the buffer to store the read bytes in
 */
static int mpu3050_read_mem(struct mpu3050 *mpu3050,
                            u8 bank,
                            u8 addr,
                            u8 len,
                            u8 *buf)
{
        int ret;

        ret = regmap_write(mpu3050->map,
                           MPU3050_BANK_SEL,
                           bank);
        if (ret)
                return ret;

        ret = regmap_write(mpu3050->map,
                           MPU3050_MEM_START_ADDR,
                           addr);
        if (ret)
                return ret;

        return regmap_bulk_read(mpu3050->map,
                                MPU3050_MEM_R_W,
                                buf,
                                len);
}

static int mpu3050_hw_init(struct mpu3050 *mpu3050)
{
        int ret;
        u8 otp[8];

        /* Reset */
        ret = regmap_update_bits(mpu3050->map,
                                 MPU3050_PWR_MGM,
                                 MPU3050_PWR_MGM_RESET,
                                 MPU3050_PWR_MGM_RESET);
        if (ret)
                return ret;

        /* Turn on the PLL */
        ret = regmap_update_bits(mpu3050->map,
                                 MPU3050_PWR_MGM,
                                 MPU3050_PWR_MGM_CLKSEL_MASK,
                                 MPU3050_PWR_MGM_PLL_Z);
        if (ret)
                return ret;

        /* Disable IRQs */
        ret = regmap_write(mpu3050->map,
                           MPU3050_INT_CFG,
                           0);
        if (ret)
                return ret;

        /* Read out the 8 bytes of OTP (one-time-programmable) memory */
        ret = mpu3050_read_mem(mpu3050,
                               (MPU3050_MEM_PRFTCH |
                                MPU3050_MEM_USER_BANK |
                                MPU3050_MEM_OTP_BANK_0),
                               0,
                               sizeof(otp),
                               otp);
        if (ret)
                return ret;

        /* This is device-unique data so it goes into the entropy pool */
        add_device_randomness(otp, sizeof(otp));

        dev_info(mpu3050->dev,
                 "die ID: %04X, wafer ID: %02X, A lot ID: %04X, "
                 "W lot ID: %03X, WP ID: %01X, rev ID: %02X\n",
                 /* Die ID, bits 0-12 */
                 (otp[1] << 8 | otp[0]) & 0x1fff,
                 /* Wafer ID, bits 13-17 */
                 ((otp[2] << 8 | otp[1]) & 0x03e0) >> 5,
                 /* A lot ID, bits 18-33 */
                 ((otp[4] << 16 | otp[3] << 8 | otp[2]) & 0x3fffc) >> 2,
                 /* W lot ID, bits 34-45 */
                 ((otp[5] << 8 | otp[4]) & 0x3ffc) >> 2,
                 /* WP ID, bits 47-49 */
                 ((otp[6] << 8 | otp[5]) & 0x0380) >> 7,
                 /* rev ID, bits 50-55 */
                 otp[6] >> 2);

        return 0;
}

static int mpu3050_power_up(struct mpu3050 *mpu3050)
{
        int ret;

        ret = regulator_bulk_enable(ARRAY_SIZE(mpu3050->regs), mpu3050->regs);
        if (ret) {
                dev_err(mpu3050->dev, "cannot enable regulators\n");
                return ret;
        }
        /*
         * 20-100 ms start-up time for register read/write according to
         * the datasheet, be on the safe side and wait 200 ms.
         */
        msleep(200);

        /* Take device out of sleep mode */
        ret = regmap_update_bits(mpu3050->map, MPU3050_PWR_MGM,
                                 MPU3050_PWR_MGM_SLEEP, 0);
        if (ret) {
                dev_err(mpu3050->dev, "error setting power mode\n");
                return ret;
        }
        msleep(10);

        return 0;
}

static int mpu3050_power_down(struct mpu3050 *mpu3050)
{
        int ret;

        /*
         * Put MPU-3050 into sleep mode before cutting regulators.
         * This is important, because we may not be the sole user
         * of the regulator so the power may stay on after this, and
         * then we would be wasting power unless we go to sleep mode
         * first.
         */
        ret = regmap_update_bits(mpu3050->map, MPU3050_PWR_MGM,
                                 MPU3050_PWR_MGM_SLEEP, MPU3050_PWR_MGM_SLEEP);
        if (ret)
                dev_err(mpu3050->dev, "error putting to sleep\n");

        ret = regulator_bulk_disable(ARRAY_SIZE(mpu3050->regs), mpu3050->regs);
        if (ret)
                dev_err(mpu3050->dev, "error disabling regulators\n");

        return 0;
}

static irqreturn_t mpu3050_irq_handler(int irq, void *p)
{
        struct iio_trigger *trig = p;
        struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
        struct mpu3050 *mpu3050 = iio_priv(indio_dev);

        if (!mpu3050->hw_irq_trigger)
                return IRQ_NONE;

        /* Get the time stamp as close in time as possible */
        mpu3050->hw_timestamp = iio_get_time_ns(indio_dev);

        return IRQ_WAKE_THREAD;
}

static irqreturn_t mpu3050_irq_thread(int irq, void *p)
{
        struct iio_trigger *trig = p;
        struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
        struct mpu3050 *mpu3050 = iio_priv(indio_dev);
        unsigned int val;
        int ret;

        /* ACK IRQ and check if it was from us */
        ret = regmap_read(mpu3050->map, MPU3050_INT_STATUS, &val);
        if (ret) {
                dev_err(mpu3050->dev, "error reading IRQ status\n");
                return IRQ_HANDLED;
        }
        if (!(val & MPU3050_INT_STATUS_RAW_RDY))
                return IRQ_NONE;

        iio_trigger_poll_chained(p);

        return IRQ_HANDLED;
}

/**
 * mpu3050_drdy_trigger_set_state() - set data ready interrupt state
 * @trig: trigger instance
 * @enable: true if trigger should be enabled, false to disable
 */
static int mpu3050_drdy_trigger_set_state(struct iio_trigger *trig,
                                          bool enable)
{
        struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
        struct mpu3050 *mpu3050 = iio_priv(indio_dev);
        unsigned int val;
        int ret;

        /* Disabling trigger: disable interrupt and return */
        if (!enable) {
                /* Disable all interrupts */
                ret = regmap_write(mpu3050->map,
                                   MPU3050_INT_CFG,
                                   0);
                if (ret)
                        dev_err(mpu3050->dev, "error disabling IRQ\n");

                /* Clear IRQ flag */
                ret = regmap_read(mpu3050->map, MPU3050_INT_STATUS, &val);
                if (ret)
                        dev_err(mpu3050->dev, "error clearing IRQ status\n");

                /* Disable all things in the FIFO and reset it */
                ret = regmap_write(mpu3050->map, MPU3050_FIFO_EN, 0);
                if (ret)
                        dev_err(mpu3050->dev, "error disabling FIFO\n");

                ret = regmap_write(mpu3050->map, MPU3050_USR_CTRL,
                                   MPU3050_USR_CTRL_FIFO_RST);
                if (ret)
                        dev_err(mpu3050->dev, "error resetting FIFO\n");

                pm_runtime_mark_last_busy(mpu3050->dev);
                pm_runtime_put_autosuspend(mpu3050->dev);
                mpu3050->hw_irq_trigger = false;

                return 0;
        } else {
                /* Else we're enabling the trigger from this point */
                pm_runtime_get_sync(mpu3050->dev);
                mpu3050->hw_irq_trigger = true;

                /* Disable all things in the FIFO */
                ret = regmap_write(mpu3050->map, MPU3050_FIFO_EN, 0);
                if (ret)
                        return ret;

                /* Reset and enable the FIFO */
                ret = regmap_update_bits(mpu3050->map, MPU3050_USR_CTRL,
                                         MPU3050_USR_CTRL_FIFO_EN |
                                         MPU3050_USR_CTRL_FIFO_RST,
                                         MPU3050_USR_CTRL_FIFO_EN |
                                         MPU3050_USR_CTRL_FIFO_RST);
                if (ret)
                        return ret;

                mpu3050->pending_fifo_footer = false;

                /* Turn on the FIFO for temp+X+Y+Z */
                ret = regmap_write(mpu3050->map, MPU3050_FIFO_EN,
                                   MPU3050_FIFO_EN_TEMP_OUT |
                                   MPU3050_FIFO_EN_GYRO_XOUT |
                                   MPU3050_FIFO_EN_GYRO_YOUT |

                                   MPU3050_FIFO_EN_GYRO_ZOUT |
                                   MPU3050_FIFO_EN_FOOTER);
                if (ret)
                        return ret;

                /* Configure the sample engine */
                ret = mpu3050_start_sampling(mpu3050);
                if (ret)
                        return ret;

                /* Clear IRQ flag */
                ret = regmap_read(mpu3050->map, MPU3050_INT_STATUS, &val);
                if (ret)
                        dev_err(mpu3050->dev, "error clearing IRQ status\n");

                /* Give us interrupts whenever there is new data ready */
                val = MPU3050_INT_RAW_RDY_EN;

                if (mpu3050->irq_actl)
                        val |= MPU3050_INT_ACTL;
                if (mpu3050->irq_latch)
                        val |= MPU3050_INT_LATCH_EN;
                if (mpu3050->irq_opendrain)
                        val |= MPU3050_INT_OPEN;

                ret = regmap_write(mpu3050->map, MPU3050_INT_CFG, val);
                if (ret)
                        return ret;
        }

        return 0;
}

static const struct iio_trigger_ops mpu3050_trigger_ops = {
        .owner = THIS_MODULE,
        .set_trigger_state = mpu3050_drdy_trigger_set_state,
};

static int mpu3050_trigger_probe(struct iio_dev *indio_dev, int irq)
{
        struct mpu3050 *mpu3050 = iio_priv(indio_dev);
        unsigned long irq_trig;
        int ret;

        mpu3050->trig = devm_iio_trigger_alloc(&indio_dev->dev,
                                               "%s-dev%d",
                                               indio_dev->name,
                                               indio_dev->id);
        if (!mpu3050->trig)
                return -ENOMEM;

        /* Check if IRQ is open drain */
        if (of_property_read_bool(mpu3050->dev->of_node, "drive-open-drain"))
                mpu3050->irq_opendrain = true;

        irq_trig = irqd_get_trigger_type(irq_get_irq_data(irq));
        /*
         * Configure the interrupt generator hardware to supply whatever
         * the interrupt is configured for, edges low/high level low/high,
         * we can provide it all.
         */
        switch (irq_trig) {
        case IRQF_TRIGGER_RISING:
                dev_info(&indio_dev->dev,
                         "pulse interrupts on the rising edge\n");
                break;
        case IRQF_TRIGGER_FALLING:
                mpu3050->irq_actl = true;
                dev_info(&indio_dev->dev,
                         "pulse interrupts on the falling edge\n");
                break;
        case IRQF_TRIGGER_HIGH:
                mpu3050->irq_latch = true;
                dev_info(&indio_dev->dev,
                         "interrupts active high level\n");
                /*
                 * With level IRQs, we mask the IRQ until it is processed,
                 * but with edge IRQs (pulses) we can queue several interrupts
                 * in the top half.
                 */
                irq_trig |= IRQF_ONESHOT;
                break;
        case IRQF_TRIGGER_LOW:
                mpu3050->irq_latch = true;
                mpu3050->irq_actl = true;
                irq_trig |= IRQF_ONESHOT;
                dev_info(&indio_dev->dev,
                         "interrupts active low level\n");
                break;
        default:
                /* This is the most preferred mode, if possible */
                dev_err(&indio_dev->dev,
                        "unsupported IRQ trigger specified (%lx), enforce "
                        "rising edge\n", irq_trig);
                irq_trig = IRQF_TRIGGER_RISING;
                break;
        }

        /* An open drain line can be shared with several devices */
        if (mpu3050->irq_opendrain)
                irq_trig |= IRQF_SHARED;

        ret = request_threaded_irq(irq,
                                   mpu3050_irq_handler,
                                   mpu3050_irq_thread,
                                   irq_trig,
                                   mpu3050->trig->name,
                                   mpu3050->trig);
        if (ret) {
                dev_err(mpu3050->dev,
                        "can't get IRQ %d, error %d\n", irq, ret);
                return ret;
        }

        mpu3050->irq = irq;
        mpu3050->trig->dev.parent = mpu3050->dev;
        mpu3050->trig->ops = &mpu3050_trigger_ops;
        iio_trigger_set_drvdata(mpu3050->trig, indio_dev);

        ret = iio_trigger_register(mpu3050->trig);
        if (ret)
                return ret;

        indio_dev->trig = iio_trigger_get(mpu3050->trig);

        return 0;
}

int mpu3050_common_probe(struct device *dev,
                         struct regmap *map,
                         int irq,
                         const char *name)
{
        struct iio_dev *indio_dev;
        struct mpu3050 *mpu3050;
        unsigned int val;
        int ret;

        indio_dev = devm_iio_device_alloc(dev, sizeof(*mpu3050));
        if (!indio_dev)
                return -ENOMEM;
        mpu3050 = iio_priv(indio_dev);

        mpu3050->dev = dev;
        mpu3050->map = map;
        mutex_init(&mpu3050->lock);
        /* Default fullscale: 2000 degrees per second */
        mpu3050->fullscale = FS_2000_DPS;
        /* 1 kHz, divide by 100, default frequency = 10 Hz */
        mpu3050->lpf = MPU3050_DLPF_CFG_188HZ;
        mpu3050->divisor = 99;

        /* Read the mounting matrix, if present */
        ret = of_iio_read_mount_matrix(dev, "mount-matrix",
                                       &mpu3050->orientation);
        if (ret)
                return ret;

        /* Fetch and turn on regulators */
        mpu3050->regs[0].supply = mpu3050_reg_vdd;
        mpu3050->regs[1].supply = mpu3050_reg_vlogic;
        ret = devm_regulator_bulk_get(dev, ARRAY_SIZE(mpu3050->regs),
                                      mpu3050->regs);
        if (ret) {
                dev_err(dev, "Cannot get regulators\n");
                return ret;
        }

        ret = mpu3050_power_up(mpu3050);
        if (ret)
                return ret;

        ret = regmap_read(map, MPU3050_CHIP_ID_REG, &val);
        if (ret) {
                dev_err(dev, "could not read device ID\n");
                ret = -ENODEV;

                goto err_power_down;
        }

        if (val != MPU3050_CHIP_ID) {
                dev_err(dev, "unsupported chip id %02x\n", (u8)val);
                ret = -ENODEV;
                goto err_power_down;
        }

        ret = regmap_read(map, MPU3050_PRODUCT_ID_REG, &val);
        if (ret) {
                dev_err(dev, "could not read device ID\n");
                ret = -ENODEV;

                goto err_power_down;
        }
        dev_info(dev, "found MPU-3050 part no: %d, version: %d\n",
                 ((val >> 4) & 0xf), (val & 0xf));

        ret = mpu3050_hw_init(mpu3050);
        if (ret)
                goto err_power_down;

        indio_dev->dev.parent = dev;
        indio_dev->channels = mpu3050_channels;
        indio_dev->num_channels = ARRAY_SIZE(mpu3050_channels);
        indio_dev->info = &mpu3050_info;
        indio_dev->available_scan_masks = mpu3050_scan_masks;
        indio_dev->modes = INDIO_DIRECT_MODE;
        indio_dev->name = name;

        ret = iio_triggered_buffer_setup(indio_dev, iio_pollfunc_store_time,
                                         mpu3050_trigger_handler,
                                         &mpu3050_buffer_setup_ops);
        if (ret) {
                dev_err(dev, "triggered buffer setup failed\n");
                goto err_power_down;
        }

        ret = iio_device_register(indio_dev);
        if (ret) {
                dev_err(dev, "device register failed\n");
                goto err_cleanup_buffer;
        }

        dev_set_drvdata(dev, indio_dev);

        /* Check if we have an assigned IRQ to use as trigger */
        if (irq) {
                ret = mpu3050_trigger_probe(indio_dev, irq);
                if (ret)
                        dev_err(dev, "failed to register trigger\n");
        }

        /* Enable runtime PM */
        pm_runtime_get_noresume(dev);
        pm_runtime_set_active(dev);
        pm_runtime_enable(dev);
        /*
         * Set autosuspend to two orders of magnitude larger than the
         * start-up time. 100ms start-up time means 10000ms autosuspend,
         * i.e. 10 seconds.
         */
        pm_runtime_set_autosuspend_delay(dev, 10000);
        pm_runtime_use_autosuspend(dev);
        pm_runtime_put(dev);

        return 0;

err_cleanup_buffer:
        iio_triggered_buffer_cleanup(indio_dev);
err_power_down:
        mpu3050_power_down(mpu3050);

        return ret;
}
EXPORT_SYMBOL(mpu3050_common_probe);

int mpu3050_common_remove(struct device *dev)
{
        struct iio_dev *indio_dev = dev_get_drvdata(dev);
        struct mpu3050 *mpu3050 = iio_priv(indio_dev);

        pm_runtime_get_sync(dev);
        pm_runtime_put_noidle(dev);
        pm_runtime_disable(dev);
        iio_triggered_buffer_cleanup(indio_dev);
        if (mpu3050->irq)
                free_irq(mpu3050->irq, mpu3050);
        iio_device_unregister(indio_dev);
        mpu3050_power_down(mpu3050);

        return 0;
}
EXPORT_SYMBOL(mpu3050_common_remove);

#ifdef CONFIG_PM
static int mpu3050_runtime_suspend(struct device *dev)
{
        return mpu3050_power_down(iio_priv(dev_get_drvdata(dev)));
}

static int mpu3050_runtime_resume(struct device *dev)
{
        return mpu3050_power_up(iio_priv(dev_get_drvdata(dev)));
}
#endif /* CONFIG_PM */

const struct dev_pm_ops mpu3050_dev_pm_ops = {
        SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
                                pm_runtime_force_resume)
        SET_RUNTIME_PM_OPS(mpu3050_runtime_suspend,
                           mpu3050_runtime_resume, NULL)
};
EXPORT_SYMBOL(mpu3050_dev_pm_ops);

MODULE_AUTHOR("Linus Walleij");
MODULE_DESCRIPTION("MPU3050 gyroscope driver");
MODULE_LICENSE("GPL");