/*
 * ADIS16220 Programmable Digital Vibration Sensor driver
 *
 * Copyright 2010 Analog Devices Inc.
 *
 * Licensed under the GPL-2 or later.
 */

#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/gpio.h>
#include <linux/delay.h>
#include <linux/mutex.h>
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/spi/spi.h>
#include <linux/slab.h>
#include <linux/sysfs.h>
#include <linux/list.h>

#include "../iio.h"
#include "../sysfs.h"
#include "accel.h"
#include "../adc/adc.h"

#include "adis16220.h"

#define DRIVER_NAME             "adis16220"

/**
 * adis16220_spi_write_reg_8() - write single byte to a register
 * @dev: device associated with child of actual device (iio_dev or iio_trig)
 * @reg_address: the address of the register to be written
 * @val: the value to write
 **/
static int adis16220_spi_write_reg_8(struct device *dev,
                u8 reg_address,
                u8 val)
{
        int ret;
        struct iio_dev *indio_dev = dev_get_drvdata(dev);
        struct adis16220_state *st = iio_dev_get_devdata(indio_dev);

        mutex_lock(&st->buf_lock);
        st->tx[0] = ADIS16220_WRITE_REG(reg_address);
        st->tx[1] = val;

        ret = spi_write(st->us, st->tx, 2);
        mutex_unlock(&st->buf_lock);

        return ret;
}

/**
 * adis16220_spi_write_reg_16() - write 2 bytes to a pair of registers
 * @dev: device associated with child of actual device (iio_dev or iio_trig)
 * @reg_address: the address of the lower of the two registers. Second register
 *               is assumed to have address one greater.
 * @val: value to be written
 **/
static int adis16220_spi_write_reg_16(struct device *dev,
                u8 lower_reg_address,
                u16 value)
{
        int ret;
        struct spi_message msg;
        struct iio_dev *indio_dev = dev_get_drvdata(dev);
        struct adis16220_state *st = iio_dev_get_devdata(indio_dev);
        struct spi_transfer xfers[] = {
                {
                        .tx_buf = st->tx,
                        .bits_per_word = 8,
                        .len = 2,
                        .cs_change = 1,
                        .delay_usecs = 35,
                }, {
                        .tx_buf = st->tx + 2,
                        .bits_per_word = 8,
                        .len = 2,
                        .cs_change = 1,
                        .delay_usecs = 35,
                },
        };

        mutex_lock(&st->buf_lock);
        st->tx[0] = ADIS16220_WRITE_REG(lower_reg_address);
        st->tx[1] = value & 0xFF;
        st->tx[2] = ADIS16220_WRITE_REG(lower_reg_address + 1);
        st->tx[3] = (value >> 8) & 0xFF;

        spi_message_init(&msg);
        spi_message_add_tail(&xfers[0], &msg);
        spi_message_add_tail(&xfers[1], &msg);
        ret = spi_sync(st->us, &msg);
        mutex_unlock(&st->buf_lock);

        return ret;
}

/**
 * adis16220_spi_read_reg_16() - read 2 bytes from a 16-bit register
 * @dev: device associated with child of actual device (iio_dev or iio_trig)
 * @reg_address: the address of the lower of the two registers. Second register
 *               is assumed to have address one greater.
 * @val: somewhere to pass back the value read
 **/
static int adis16220_spi_read_reg_16(struct device *dev,
                u8 lower_reg_address,
                u16 *val)
{
        struct spi_message msg;
        struct iio_dev *indio_dev = dev_get_drvdata(dev);
        struct adis16220_state *st = iio_dev_get_devdata(indio_dev);
        int ret;
        struct spi_transfer xfers[] = {
                {
                        .tx_buf = st->tx,
                        .bits_per_word = 8,
                        .len = 2,
                        .cs_change = 1,
                        .delay_usecs = 35,
                }, {
                        .rx_buf = st->rx,
                        .bits_per_word = 8,
                        .len = 2,
                        .cs_change = 1,
                        .delay_usecs = 35,
                },
        };

        mutex_lock(&st->buf_lock);
        st->tx[0] = ADIS16220_READ_REG(lower_reg_address);
        st->tx[1] = 0;

        spi_message_init(&msg);
        spi_message_add_tail(&xfers[0], &msg);
        spi_message_add_tail(&xfers[1], &msg);
        ret = spi_sync(st->us, &msg);
        if (ret) {
                dev_err(&st->us->dev,
                        "problem when reading 16 bit register 0x%02X",
                        lower_reg_address);
                goto error_ret;
        }
        *val = (st->rx[0] << 8) | st->rx[1];

error_ret:
        mutex_unlock(&st->buf_lock);
        return ret;
}

static ssize_t adis16220_spi_read_signed(struct device *dev,
                struct device_attribute *attr,
                char *buf,
                unsigned bits)
{
        int ret;
        s16 val = 0;
        unsigned shift = 16 - bits;
        struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);

        ret = adis16220_spi_read_reg_16(dev, this_attr->address, (u16 *)&val);
        if (ret)
                return ret;

        val = ((s16)(val << shift) >> shift);
        return sprintf(buf, "%d\n", val);
}

static ssize_t adis16220_read_12bit_unsigned(struct device *dev,
                struct device_attribute *attr,
                char *buf)
{
        int ret;
        u16 val = 0;
        struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);

        ret = adis16220_spi_read_reg_16(dev, this_attr->address, &val);
        if (ret)
                return ret;

        return sprintf(buf, "%u\n", val & 0x0FFF);
}

static ssize_t adis16220_read_16bit(struct device *dev,
                struct device_attribute *attr,
                char *buf)
{
        struct iio_dev *indio_dev = dev_get_drvdata(dev);
        ssize_t ret;

        /* Take the iio_dev status lock */
        mutex_lock(&indio_dev->mlock);
        ret =  adis16220_spi_read_signed(dev, attr, buf, 16);
        mutex_unlock(&indio_dev->mlock);

        return ret;
}

static ssize_t adis16220_write_16bit(struct device *dev,
                struct device_attribute *attr,
                const char *buf,
                size_t len)
{
        struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
        int ret;
        long val;

        ret = strict_strtol(buf, 10, &val);
        if (ret)
                goto error_ret;
        ret = adis16220_spi_write_reg_16(dev, this_attr->address, val);

error_ret:
        return ret ? ret : len;
}

static int adis16220_capture(struct device *dev)
{
        int ret;
        ret = adis16220_spi_write_reg_16(dev,
                        ADIS16220_GLOB_CMD,
                        0xBF08); /* initiates a manual data capture */
        if (ret)
                dev_err(dev, "problem beginning capture");

        msleep(10); /* delay for capture to finish */

        return ret;
}

static int adis16220_reset(struct device *dev)
{
        int ret;
        ret = adis16220_spi_write_reg_8(dev,
                        ADIS16220_GLOB_CMD,
                        ADIS16220_GLOB_CMD_SW_RESET);
        if (ret)
                dev_err(dev, "problem resetting device");

        return ret;
}

static ssize_t adis16220_write_reset(struct device *dev,
                struct device_attribute *attr,
                const char *buf, size_t len)
{
        if (len < 1)
                return -1;
        switch (buf[0]) {
        case '1':
        case 'y':
        case 'Y':
                return adis16220_reset(dev) == 0 ? len : -EIO;
        }
        return -1;
}

static ssize_t adis16220_write_capture(struct device *dev,
                struct device_attribute *attr,
                const char *buf, size_t len)
{
        if (len < 1)
                return -1;
        switch (buf[0]) {
        case '1':
        case 'y':
        case 'Y':
                return adis16220_capture(dev) == 0 ? len : -EIO;
        }
        return -1;
}

static int adis16220_check_status(struct device *dev)
{
        u16 status;
        int ret;

        ret = adis16220_spi_read_reg_16(dev, ADIS16220_DIAG_STAT, &status);

        if (ret < 0) {
                dev_err(dev, "Reading status failed\n");
                goto error_ret;
        }
        ret = status & 0x7F;

        if (status & ADIS16220_DIAG_STAT_VIOLATION)
                dev_err(dev, "Capture period violation/interruption\n");
        if (status & ADIS16220_DIAG_STAT_SPI_FAIL)
                dev_err(dev, "SPI failure\n");
        if (status & ADIS16220_DIAG_STAT_FLASH_UPT)
                dev_err(dev, "Flash update failed\n");
        if (status & ADIS16220_DIAG_STAT_POWER_HIGH)
                dev_err(dev, "Power supply above 3.625V\n");
        if (status & ADIS16220_DIAG_STAT_POWER_LOW)
                dev_err(dev, "Power supply below 3.15V\n");

error_ret:
        return ret;
}

static int adis16220_self_test(struct device *dev)
{
        int ret;
        ret = adis16220_spi_write_reg_16(dev,
                        ADIS16220_MSC_CTRL,
                        ADIS16220_MSC_CTRL_SELF_TEST_EN);
        if (ret) {
                dev_err(dev, "problem starting self test");
                goto err_ret;
        }

        adis16220_check_status(dev);

err_ret:
        return ret;
}

static int adis16220_initial_setup(struct adis16220_state *st)
{
        int ret;
        struct device *dev = &st->indio_dev->dev;

        /* Do self test */
        ret = adis16220_self_test(dev);
        if (ret) {
                dev_err(dev, "self test failure");
                goto err_ret;
        }

        /* Read status register to check the result */
        ret = adis16220_check_status(dev);
        if (ret) {
                adis16220_reset(dev);
                dev_err(dev, "device not playing ball -> reset");
                msleep(ADIS16220_STARTUP_DELAY);
                ret = adis16220_check_status(dev);
                if (ret) {
                        dev_err(dev, "giving up");
                        goto err_ret;
                }
        }

        printk(KERN_INFO DRIVER_NAME ": at CS%d (irq %d)\n",
                        st->us->chip_select, st->us->irq);

err_ret:
        return ret;
}

static ssize_t adis16220_capture_buffer_read(struct adis16220_state *st,
                                        char *buf,
                                        loff_t off,
                                        size_t count,
                                        int addr)
{
        struct spi_message msg;
        struct spi_transfer xfers[] = {
                {
                        .tx_buf = st->tx,
                        .bits_per_word = 8,
                        .len = 2,
                        .cs_change = 1,
                        .delay_usecs = 25,
                }, {
                        .tx_buf = st->tx,
                        .rx_buf = st->rx,
                        .bits_per_word = 8,
                        .cs_change = 1,
                        .delay_usecs = 25,
                },
        };
        int ret;
        int i;

        if (unlikely(!count))
                return count;

        if ((off >= ADIS16220_CAPTURE_SIZE) || (count & 1) || (off & 1))
                return -EINVAL;

        if (off + count > ADIS16220_CAPTURE_SIZE)
                count = ADIS16220_CAPTURE_SIZE - off;

        /* write the begin position of capture buffer */
        ret = adis16220_spi_write_reg_16(&st->indio_dev->dev,
                                        ADIS16220_CAPT_PNTR,
                                        off > 1);
        if (ret)
                return -EIO;

        /* read count/2 values from capture buffer */
        mutex_lock(&st->buf_lock);

        for (i = 0; i < count; i += 2) {
                st->tx[i] = ADIS16220_READ_REG(addr);
                st->tx[i + 1] = 0;
        }
        xfers[1].len = count;

        spi_message_init(&msg);
        spi_message_add_tail(&xfers[0], &msg);
        spi_message_add_tail(&xfers[1], &msg);
        ret = spi_sync(st->us, &msg);
        if (ret) {

                mutex_unlock(&st->buf_lock);
                return -EIO;
        }

        memcpy(buf, st->rx, count);

        mutex_unlock(&st->buf_lock);
        return count;
}

static ssize_t adis16220_accel_bin_read(struct file *filp, struct kobject *kobj,
                                        struct bin_attribute *attr,
                                        char *buf,
                                        loff_t off,
                                        size_t count)
{
        struct device *dev = container_of(kobj, struct device, kobj);
        struct iio_dev *indio_dev = dev_get_drvdata(dev);
        struct adis16220_state *st = iio_dev_get_devdata(indio_dev);

        return adis16220_capture_buffer_read(st, buf,
                                        off, count,
                                        ADIS16220_CAPT_BUFA);
}

static struct bin_attribute accel_bin = {
        .attr = {
                .name = "accel_bin",
                .mode = S_IRUGO,
        },
        .read = adis16220_accel_bin_read,
        .size = ADIS16220_CAPTURE_SIZE,
};

static ssize_t adis16220_adc1_bin_read(struct file *filp, struct kobject *kobj,
                                struct bin_attribute *attr,
                                char *buf, loff_t off,
                                size_t count)
{
        struct device *dev = container_of(kobj, struct device, kobj);
        struct iio_dev *indio_dev = dev_get_drvdata(dev);
        struct adis16220_state *st = iio_dev_get_devdata(indio_dev);

        return adis16220_capture_buffer_read(st, buf,
                                        off, count,
                                        ADIS16220_CAPT_BUF1);
}

static struct bin_attribute adc1_bin = {
        .attr = {
                .name = "in0_bin",
                .mode = S_IRUGO,
        },
        .read =  adis16220_adc1_bin_read,
        .size = ADIS16220_CAPTURE_SIZE,
};

static ssize_t adis16220_adc2_bin_read(struct file *filp, struct kobject *kobj,
                                struct bin_attribute *attr,
                                char *buf, loff_t off,
                                size_t count)
{
        struct device *dev = container_of(kobj, struct device, kobj);
        struct iio_dev *indio_dev = dev_get_drvdata(dev);
        struct adis16220_state *st = iio_dev_get_devdata(indio_dev);

        return adis16220_capture_buffer_read(st, buf,
                                        off, count,
                                        ADIS16220_CAPT_BUF2);
}


static struct bin_attribute adc2_bin = {
        .attr = {
                .name = "in1_bin",
                .mode = S_IRUGO,
        },
        .read =  adis16220_adc2_bin_read,
        .size = ADIS16220_CAPTURE_SIZE,
};

static IIO_DEV_ATTR_IN_NAMED_RAW(0, supply, adis16220_read_12bit_unsigned,
                ADIS16220_CAPT_SUPPLY);
static IIO_CONST_ATTR_IN_NAMED_SCALE(0, supply, "0.0012207");
static IIO_DEV_ATTR_ACCEL(adis16220_read_16bit, ADIS16220_CAPT_BUFA);
static IIO_DEVICE_ATTR(accel_peak_raw, S_IRUGO, adis16220_read_16bit,
                NULL, ADIS16220_CAPT_PEAKA);
static IIO_DEV_ATTR_ACCEL_OFFSET(S_IWUSR | S_IRUGO,
                adis16220_read_16bit,
                adis16220_write_16bit,
                ADIS16220_ACCL_NULL);
static IIO_CONST_ATTR_ACCEL_SCALE("0.18704223545");
static IIO_DEV_ATTR_TEMP_RAW(adis16220_read_12bit_unsigned);
static IIO_CONST_ATTR_TEMP_OFFSET("25");
static IIO_CONST_ATTR_TEMP_SCALE("-0.47");

static IIO_DEV_ATTR_IN_RAW(1, adis16220_read_16bit, ADIS16220_CAPT_BUF1);
static IIO_DEV_ATTR_IN_RAW(2, adis16220_read_16bit, ADIS16220_CAPT_BUF2);

static IIO_DEVICE_ATTR(reset, S_IWUSR, NULL,
                adis16220_write_reset, 0);

#define IIO_DEV_ATTR_CAPTURE(_store)                            \
        IIO_DEVICE_ATTR(capture, S_IWUSR, NULL, _store, 0)

static IIO_DEV_ATTR_CAPTURE(adis16220_write_capture);

#define IIO_DEV_ATTR_CAPTURE_COUNT(_mode, _show, _store, _addr)         \
        IIO_DEVICE_ATTR(capture_count, _mode, _show, _store, _addr)

static IIO_DEV_ATTR_CAPTURE_COUNT(S_IWUSR | S_IRUGO,
                adis16220_read_16bit,
                adis16220_write_16bit,
                ADIS16220_CAPT_PNTR);

static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("100200");

static IIO_CONST_ATTR_NAME("adis16220");

static struct attribute *adis16220_attributes[] = {
        &iio_dev_attr_in0_supply_raw.dev_attr.attr,
        &iio_const_attr_in0_supply_scale.dev_attr.attr,
        &iio_dev_attr_accel_raw.dev_attr.attr,
        &iio_dev_attr_accel_offset.dev_attr.attr,
        &iio_dev_attr_accel_peak_raw.dev_attr.attr,
        &iio_const_attr_accel_scale.dev_attr.attr,
        &iio_dev_attr_temp_raw.dev_attr.attr,
        &iio_dev_attr_in1_raw.dev_attr.attr,
        &iio_dev_attr_in2_raw.dev_attr.attr,
        &iio_const_attr_temp_offset.dev_attr.attr,
        &iio_const_attr_temp_scale.dev_attr.attr,
        &iio_const_attr_sampling_frequency_available.dev_attr.attr,
        &iio_dev_attr_reset.dev_attr.attr,
        &iio_dev_attr_capture.dev_attr.attr,
        &iio_dev_attr_capture_count.dev_attr.attr,
        &iio_const_attr_name.dev_attr.attr,
        NULL
};

static const struct attribute_group adis16220_attribute_group = {
        .attrs = adis16220_attributes,
};

static int __devinit adis16220_probe(struct spi_device *spi)
{
        int ret, regdone = 0;
        struct adis16220_state *st = kzalloc(sizeof *st, GFP_KERNEL);
        if (!st) {
                ret =  -ENOMEM;
                goto error_ret;
        }
        /* this is only used for removal purposes */
        spi_set_drvdata(spi, st);

        /* Allocate the comms buffers */
        st->rx = kzalloc(sizeof(*st->rx)*ADIS16220_MAX_RX, GFP_KERNEL);
        if (st->rx == NULL) {
                ret = -ENOMEM;
                goto error_free_st;
        }
        st->tx = kzalloc(sizeof(*st->tx)*ADIS16220_MAX_TX, GFP_KERNEL);
        if (st->tx == NULL) {
                ret = -ENOMEM;
                goto error_free_rx;
        }
        st->us = spi;
        mutex_init(&st->buf_lock);
        /* setup the industrialio driver allocated elements */
        st->indio_dev = iio_allocate_device();
        if (st->indio_dev == NULL) {
                ret = -ENOMEM;
                goto error_free_tx;
        }

        st->indio_dev->dev.parent = &spi->dev;
        st->indio_dev->attrs = &adis16220_attribute_group;
        st->indio_dev->dev_data = (void *)(st);
        st->indio_dev->driver_module = THIS_MODULE;
        st->indio_dev->modes = INDIO_DIRECT_MODE;

        ret = iio_device_register(st->indio_dev);
        if (ret)
                goto error_free_dev;
        regdone = 1;

        ret = sysfs_create_bin_file(&st->indio_dev->dev.kobj, &accel_bin);
        if (ret)
                goto error_free_dev;

        ret = sysfs_create_bin_file(&st->indio_dev->dev.kobj, &adc1_bin);
        if (ret)
                goto error_rm_accel_bin;

        ret = sysfs_create_bin_file(&st->indio_dev->dev.kobj, &adc2_bin);
        if (ret)
                goto error_rm_adc1_bin;

        /* Get the device into a sane initial state */
        ret = adis16220_initial_setup(st);
        if (ret)
                goto error_rm_adc2_bin;
        return 0;

error_rm_adc2_bin:
        sysfs_remove_bin_file(&st->indio_dev->dev.kobj, &adc2_bin);
error_rm_adc1_bin:
        sysfs_remove_bin_file(&st->indio_dev->dev.kobj, &adc1_bin);
error_rm_accel_bin:
        sysfs_remove_bin_file(&st->indio_dev->dev.kobj, &accel_bin);
error_free_dev:
        if (regdone)
                iio_device_unregister(st->indio_dev);
        else
                iio_free_device(st->indio_dev);
error_free_tx:
        kfree(st->tx);
error_free_rx:
        kfree(st->rx);
error_free_st:
        kfree(st);
error_ret:
        return ret;
}

static int adis16220_remove(struct spi_device *spi)
{
        struct adis16220_state *st = spi_get_drvdata(spi);
        struct iio_dev *indio_dev = st->indio_dev;

        flush_scheduled_work();

        sysfs_remove_bin_file(&st->indio_dev->dev.kobj, &adc2_bin);
        sysfs_remove_bin_file(&st->indio_dev->dev.kobj, &adc1_bin);
        sysfs_remove_bin_file(&st->indio_dev->dev.kobj, &accel_bin);
        iio_device_unregister(indio_dev);
        kfree(st->tx);
        kfree(st->rx);
        kfree(st);

        return 0;
}

static struct spi_driver adis16220_driver = {
        .driver = {
                .name = "adis16220",
                .owner = THIS_MODULE,
        },
        .probe = adis16220_probe,
        .remove = __devexit_p(adis16220_remove),
};

static __init int adis16220_init(void)
{
        return spi_register_driver(&adis16220_driver);
}
module_init(adis16220_init);

static __exit void adis16220_exit(void)
{
        spi_unregister_driver(&adis16220_driver);
}
module_exit(adis16220_exit);

MODULE_AUTHOR("Barry Song <21cnbao@gmail.com>");
MODULE_DESCRIPTION("Analog Devices ADIS16220 Digital Vibration Sensor");
MODULE_LICENSE("GPL v2");