hid-sensor-attributes.c

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/*
 * HID Sensors Driver
 * Copyright (c) 2012, Intel Corporation.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
 *
 */
#include <linux/device.h>
#include <linux/platform_device.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/slab.h>
#include <linux/hid-sensor-hub.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include "hid-sensor-attributes.h"

static int pow_10(unsigned power)
{
    int i;
    int ret = 1;
    for (i = 0; i < power; ++i)
        ret = ret * 10;

    return ret;
}

static void simple_div(int dividend, int divisor, int *whole,
                int *micro_frac)
{
    int rem;
    int exp = 0;

    *micro_frac = 0;
    if (divisor == 0) {
        *whole = 0;
        return;
    }
    *whole = dividend/divisor;
    rem = dividend % divisor;
    if (rem) {
        while (rem <= divisor) {
            rem *= 10;
            exp++;
        }
        *micro_frac = (rem / divisor) * pow_10(6-exp);
    }
}

static void split_micro_fraction(unsigned int no, int exp, int *val1, int *val2)
{
    *val1 = no/pow_10(exp);
    *val2 = no%pow_10(exp) * pow_10(6-exp);
}

/*
VTF format uses exponent and variable size format.
For example if the size is 2 bytes
0x0067 with VTF16E14 format -> +1.03
To convert just change to 0x67 to decimal and use two decimal as E14 stands
for 10^-2.
Negative numbers are 2's complement
*/
static void convert_from_vtf_format(u32 value, int size, int exp,
                    int *val1, int *val2)
{
    int sign = 1;

    if (value & BIT(size*8 - 1)) {
        value =  ((1LL << (size * 8)) - value);
        sign = -1;
    }
    exp = hid_sensor_convert_exponent(exp);
    if (exp >= 0) {
        *val1 = sign * value * pow_10(exp);
        *val2 = 0;
    } else {
        split_micro_fraction(value, -exp, val1, val2);
        if (*val1)
            *val1 = sign * (*val1);
        else
            *val2 = sign * (*val2);
    }
}

static u32 convert_to_vtf_format(int size, int exp, int val1, int val2)
{
    u32 value;
    int sign = 1;

    if (val1 < 0 || val2 < 0)
        sign = -1;
    exp = hid_sensor_convert_exponent(exp);
    if (exp < 0) {
        value = abs(val1) * pow_10(-exp);
        value += abs(val2) / pow_10(6+exp);
    } else
        value = abs(val1) / pow_10(exp);
    if (sign < 0)
        value =  ((1LL << (size * 8)) - value);

    return value;
}

int hid_sensor_read_samp_freq_value(struct hid_sensor_iio_common *st,
                int *val1, int *val2)
{
    s32 value;
    int ret;

    ret = sensor_hub_get_feature(st->hsdev,
        st->poll.report_id,
        st->poll.index, &value);
    if (ret < 0 || value < 0) {
        *val1 = *val2 = 0;
        return -EINVAL;
    } else {
        if (st->poll.units == HID_USAGE_SENSOR_UNITS_MILLISECOND)
            simple_div(1000, value, val1, val2);
        else if (st->poll.units == HID_USAGE_SENSOR_UNITS_SECOND)
            simple_div(1, value, val1, val2);
        else {
            *val1 = *val2 = 0;
            return -EINVAL;
        }
    }

    return IIO_VAL_INT_PLUS_MICRO;
}
EXPORT_SYMBOL(hid_sensor_read_samp_freq_value);

int hid_sensor_write_samp_freq_value(struct hid_sensor_iio_common *st,
                int val1, int val2)
{
    s32 value;
    int ret;

    if (val1 < 0 || val2 < 0)
        ret = -EINVAL;

    value = val1 * pow_10(6) + val2;
    if (value) {
        if (st->poll.units == HID_USAGE_SENSOR_UNITS_MILLISECOND)
            value = pow_10(9)/value;
        else if (st->poll.units == HID_USAGE_SENSOR_UNITS_SECOND)
            value = pow_10(6)/value;
        else
            value = 0;
    }
    ret = sensor_hub_set_feature(st->hsdev,
        st->poll.report_id,
        st->poll.index, value);
    if (ret < 0 || value < 0)
        ret = -EINVAL;

    return ret;
}
EXPORT_SYMBOL(hid_sensor_write_samp_freq_value);

int hid_sensor_read_raw_hyst_value(struct hid_sensor_iio_common *st,
                int *val1, int *val2)
{
    s32 value;
    int ret;

    ret = sensor_hub_get_feature(st->hsdev,
        st->sensitivity.report_id,
        st->sensitivity.index, &value);
    if (ret < 0 || value < 0) {
        *val1 = *val2 = 0;
        return -EINVAL;
    } else {
        convert_from_vtf_format(value, st->sensitivity.size,
                    st->sensitivity.unit_expo,
                    val1, val2);
    }

    return IIO_VAL_INT_PLUS_MICRO;
}
EXPORT_SYMBOL(hid_sensor_read_raw_hyst_value);

int hid_sensor_write_raw_hyst_value(struct hid_sensor_iio_common *st,
                    int val1, int val2)
{
    s32 value;
    int ret;

    value = convert_to_vtf_format(st->sensitivity.size,
                st->sensitivity.unit_expo,
                val1, val2);
    ret = sensor_hub_set_feature(st->hsdev,
        st->sensitivity.report_id,
        st->sensitivity.index, value);
    if (ret < 0 || value < 0)
        ret = -EINVAL;

    return ret;
}
EXPORT_SYMBOL(hid_sensor_write_raw_hyst_value);

int hid_sensor_parse_common_attributes(struct hid_sensor_hub_device *hsdev,
                    u32 usage_id,
                    struct hid_sensor_iio_common *st)
{

    sensor_hub_input_get_attribute_info(hsdev,
                    HID_FEATURE_REPORT, usage_id,
                    HID_USAGE_SENSOR_PROP_REPORT_INTERVAL,
                    &st->poll);

    sensor_hub_input_get_attribute_info(hsdev,
                    HID_FEATURE_REPORT, usage_id,
                    HID_USAGE_SENSOR_PROP_REPORT_STATE,
                    &st->report_state);

    sensor_hub_input_get_attribute_info(hsdev,
                    HID_FEATURE_REPORT, usage_id,
                    HID_USAGE_SENSOR_PROY_POWER_STATE,
                    &st->power_state);

    sensor_hub_input_get_attribute_info(hsdev,
            HID_FEATURE_REPORT, usage_id,
            HID_USAGE_SENSOR_PROP_SENSITIVITY_ABS,
             &st->sensitivity);

    hid_dbg(hsdev->hdev, "common attributes: %x:%x, %x:%x, %x:%x %x:%x\n",
            st->poll.index, st->poll.report_id,
            st->report_state.index, st->report_state.report_id,
            st->power_state.index, st->power_state.report_id,
            st->sensitivity.index, st->sensitivity.report_id);

    return 0;
}
EXPORT_SYMBOL(hid_sensor_parse_common_attributes);

MODULE_AUTHOR("Srinivas Pandruvada <[email protected]>");
MODULE_DESCRIPTION("HID Sensor common attribute processing");
MODULE_LICENSE("GPL");