linux/drivers/iio/common/hid-sensors/hid-sensor-attributes.c
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   1/*
   2 * HID Sensors Driver
   3 * Copyright (c) 2012, Intel Corporation.
   4 *
   5 * This program is free software; you can redistribute it and/or modify it
   6 * under the terms and conditions of the GNU General Public License,
   7 * version 2, as published by the Free Software Foundation.
   8 *
   9 * This program is distributed in the hope it will be useful, but WITHOUT
  10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  12 * more details.
  13 *
  14 * You should have received a copy of the GNU General Public License along with
  15 * this program; if not, write to the Free Software Foundation, Inc.,
  16 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
  17 *
  18 */
  19#include <linux/device.h>
  20#include <linux/platform_device.h>
  21#include <linux/module.h>
  22#include <linux/interrupt.h>
  23#include <linux/irq.h>
  24#include <linux/slab.h>
  25#include <linux/hid-sensor-hub.h>
  26#include <linux/iio/iio.h>
  27#include <linux/iio/sysfs.h>
  28
  29static int pow_10(unsigned power)
  30{
  31        int i;
  32        int ret = 1;
  33        for (i = 0; i < power; ++i)
  34                ret = ret * 10;
  35
  36        return ret;
  37}
  38
  39static void simple_div(int dividend, int divisor, int *whole,
  40                                int *micro_frac)
  41{
  42        int rem;
  43        int exp = 0;
  44
  45        *micro_frac = 0;
  46        if (divisor == 0) {
  47                *whole = 0;
  48                return;
  49        }
  50        *whole = dividend/divisor;
  51        rem = dividend % divisor;
  52        if (rem) {
  53                while (rem <= divisor) {
  54                        rem *= 10;
  55                        exp++;
  56                }
  57                *micro_frac = (rem / divisor) * pow_10(6-exp);
  58        }
  59}
  60
  61static void split_micro_fraction(unsigned int no, int exp, int *val1, int *val2)
  62{
  63        *val1 = no/pow_10(exp);
  64        *val2 = no%pow_10(exp) * pow_10(6-exp);
  65}
  66
  67/*
  68VTF format uses exponent and variable size format.
  69For example if the size is 2 bytes
  700x0067 with VTF16E14 format -> +1.03
  71To convert just change to 0x67 to decimal and use two decimal as E14 stands
  72for 10^-2.
  73Negative numbers are 2's complement
  74*/
  75static void convert_from_vtf_format(u32 value, int size, int exp,
  76                                        int *val1, int *val2)
  77{
  78        int sign = 1;
  79
  80        if (value & BIT(size*8 - 1)) {
  81                value =  ((1LL << (size * 8)) - value);
  82                sign = -1;
  83        }
  84        exp = hid_sensor_convert_exponent(exp);
  85        if (exp >= 0) {
  86                *val1 = sign * value * pow_10(exp);
  87                *val2 = 0;
  88        } else {
  89                split_micro_fraction(value, -exp, val1, val2);
  90                if (*val1)
  91                        *val1 = sign * (*val1);
  92                else
  93                        *val2 = sign * (*val2);
  94        }
  95}
  96
  97static u32 convert_to_vtf_format(int size, int exp, int val1, int val2)
  98{
  99        u32 value;
 100        int sign = 1;
 101
 102        if (val1 < 0 || val2 < 0)
 103                sign = -1;
 104        exp = hid_sensor_convert_exponent(exp);
 105        if (exp < 0) {
 106                value = abs(val1) * pow_10(-exp);
 107                value += abs(val2) / pow_10(6+exp);
 108        } else
 109                value = abs(val1) / pow_10(exp);
 110        if (sign < 0)
 111                value =  ((1LL << (size * 8)) - value);
 112
 113        return value;
 114}
 115
 116int hid_sensor_read_samp_freq_value(struct hid_sensor_common *st,
 117                                int *val1, int *val2)
 118{
 119        s32 value;
 120        int ret;
 121
 122        ret = sensor_hub_get_feature(st->hsdev,
 123                st->poll.report_id,
 124                st->poll.index, &value);
 125        if (ret < 0 || value < 0) {
 126                *val1 = *val2 = 0;
 127                return -EINVAL;
 128        } else {
 129                if (st->poll.units == HID_USAGE_SENSOR_UNITS_MILLISECOND)
 130                        simple_div(1000, value, val1, val2);
 131                else if (st->poll.units == HID_USAGE_SENSOR_UNITS_SECOND)
 132                        simple_div(1, value, val1, val2);
 133                else {
 134                        *val1 = *val2 = 0;
 135                        return -EINVAL;
 136                }
 137        }
 138
 139        return IIO_VAL_INT_PLUS_MICRO;
 140}
 141EXPORT_SYMBOL(hid_sensor_read_samp_freq_value);
 142
 143int hid_sensor_write_samp_freq_value(struct hid_sensor_common *st,
 144                                int val1, int val2)
 145{
 146        s32 value;
 147        int ret;
 148
 149        if (val1 < 0 || val2 < 0)
 150                ret = -EINVAL;
 151
 152        value = val1 * pow_10(6) + val2;
 153        if (value) {
 154                if (st->poll.units == HID_USAGE_SENSOR_UNITS_MILLISECOND)
 155                        value = pow_10(9)/value;
 156                else if (st->poll.units == HID_USAGE_SENSOR_UNITS_SECOND)
 157                        value = pow_10(6)/value;
 158                else
 159                        value = 0;
 160        }
 161        ret = sensor_hub_set_feature(st->hsdev,
 162                st->poll.report_id,
 163                st->poll.index, value);
 164        if (ret < 0 || value < 0)
 165                ret = -EINVAL;
 166
 167        return ret;
 168}
 169EXPORT_SYMBOL(hid_sensor_write_samp_freq_value);
 170
 171int hid_sensor_read_raw_hyst_value(struct hid_sensor_common *st,
 172                                int *val1, int *val2)
 173{
 174        s32 value;
 175        int ret;
 176
 177        ret = sensor_hub_get_feature(st->hsdev,
 178                st->sensitivity.report_id,
 179                st->sensitivity.index, &value);
 180        if (ret < 0 || value < 0) {
 181                *val1 = *val2 = 0;
 182                return -EINVAL;
 183        } else {
 184                convert_from_vtf_format(value, st->sensitivity.size,
 185                                        st->sensitivity.unit_expo,
 186                                        val1, val2);
 187        }
 188
 189        return IIO_VAL_INT_PLUS_MICRO;
 190}
 191EXPORT_SYMBOL(hid_sensor_read_raw_hyst_value);
 192
 193int hid_sensor_write_raw_hyst_value(struct hid_sensor_common *st,
 194                                        int val1, int val2)
 195{
 196        s32 value;
 197        int ret;
 198
 199        value = convert_to_vtf_format(st->sensitivity.size,
 200                                st->sensitivity.unit_expo,
 201                                val1, val2);
 202        ret = sensor_hub_set_feature(st->hsdev,
 203                st->sensitivity.report_id,
 204                st->sensitivity.index, value);
 205        if (ret < 0 || value < 0)
 206                ret = -EINVAL;
 207
 208        return ret;
 209}
 210EXPORT_SYMBOL(hid_sensor_write_raw_hyst_value);
 211
 212int hid_sensor_parse_common_attributes(struct hid_sensor_hub_device *hsdev,
 213                                        u32 usage_id,
 214                                        struct hid_sensor_common *st)
 215{
 216
 217        sensor_hub_input_get_attribute_info(hsdev,
 218                                        HID_FEATURE_REPORT, usage_id,
 219                                        HID_USAGE_SENSOR_PROP_REPORT_INTERVAL,
 220                                        &st->poll);
 221
 222        sensor_hub_input_get_attribute_info(hsdev,
 223                                        HID_FEATURE_REPORT, usage_id,
 224                                        HID_USAGE_SENSOR_PROP_REPORT_STATE,
 225                                        &st->report_state);
 226
 227        sensor_hub_input_get_attribute_info(hsdev,
 228                                        HID_FEATURE_REPORT, usage_id,
 229                                        HID_USAGE_SENSOR_PROY_POWER_STATE,
 230                                        &st->power_state);
 231
 232        sensor_hub_input_get_attribute_info(hsdev,
 233                        HID_FEATURE_REPORT, usage_id,
 234                        HID_USAGE_SENSOR_PROP_SENSITIVITY_ABS,
 235                         &st->sensitivity);
 236
 237        hid_dbg(hsdev->hdev, "common attributes: %x:%x, %x:%x, %x:%x %x:%x\n",
 238                        st->poll.index, st->poll.report_id,
 239                        st->report_state.index, st->report_state.report_id,
 240                        st->power_state.index, st->power_state.report_id,
 241                        st->sensitivity.index, st->sensitivity.report_id);
 242
 243        return 0;
 244}
 245EXPORT_SYMBOL(hid_sensor_parse_common_attributes);
 246
 247MODULE_AUTHOR("Srinivas Pandruvada <srinivas.pandruvada@intel.com>");
 248MODULE_DESCRIPTION("HID Sensor common attribute processing");
 249MODULE_LICENSE("GPL");
 250