On 25/09/15 14:56, Ludovic Tancerel wrote:
> Measurement specialties drivers common part.
> These functions are used by further drivers in the patchset: TSYS01, TSYS02D, HTU21, MS5637, MS8607
>
> Signed-off-by: Ludovic Tancerel <ludovic.tancerel@xxxxxxxxxxxxxxxxx>
A few more bits and bobs inline.
> ---
> drivers/iio/common/Kconfig | 1 +
> drivers/iio/common/Makefile | 1 +
> drivers/iio/common/ms_sensors/Kconfig | 6 +
> drivers/iio/common/ms_sensors/Makefile | 5 +
> drivers/iio/common/ms_sensors/ms_sensors_i2c.c | 645 +++++++++++++++++++++++++
> drivers/iio/common/ms_sensors/ms_sensors_i2c.h | 53 ++
> 6 files changed, 711 insertions(+)
> create mode 100644 drivers/iio/common/ms_sensors/Kconfig
> create mode 100644 drivers/iio/common/ms_sensors/Makefile
> create mode 100644 drivers/iio/common/ms_sensors/ms_sensors_i2c.c
> create mode 100644 drivers/iio/common/ms_sensors/ms_sensors_i2c.h
>
> diff --git a/drivers/iio/common/Kconfig b/drivers/iio/common/Kconfig
> index 790f106..26a6026 100644
> --- a/drivers/iio/common/Kconfig
> +++ b/drivers/iio/common/Kconfig
> @@ -3,5 +3,6 @@
> #
>
> source "drivers/iio/common/hid-sensors/Kconfig"
> +source "drivers/iio/common/ms_sensors/Kconfig"
> source "drivers/iio/common/ssp_sensors/Kconfig"
> source "drivers/iio/common/st_sensors/Kconfig"
> diff --git a/drivers/iio/common/Makefile b/drivers/iio/common/Makefile
> index b1e4d9c..585da6a 100644
> --- a/drivers/iio/common/Makefile
> +++ b/drivers/iio/common/Makefile
> @@ -8,5 +8,6 @@
>
> # When adding new entries keep the list in alphabetical order
> obj-y += hid-sensors/
> +obj-y += ms_sensors/
> obj-y += ssp_sensors/
> obj-y += st_sensors/
> diff --git a/drivers/iio/common/ms_sensors/Kconfig b/drivers/iio/common/ms_sensors/Kconfig
> new file mode 100644
> index 0000000..b28a92b
> --- /dev/null
> +++ b/drivers/iio/common/ms_sensors/Kconfig
> @@ -0,0 +1,6 @@
> +#
> +# Measurements Specialties sensors common library
> +#
> +
> +config IIO_MS_SENSORS_I2C
> + tristate
> diff --git a/drivers/iio/common/ms_sensors/Makefile b/drivers/iio/common/ms_sensors/Makefile
> new file mode 100644
> index 0000000..7846428
> --- /dev/null
> +++ b/drivers/iio/common/ms_sensors/Makefile
> @@ -0,0 +1,5 @@
> +#
> +# Makefile for the Measurement Specialties sensor common modules.
> +#
> +
> +obj-$(CONFIG_IIO_MS_SENSORS_I2C) += ms_sensors_i2c.o
> diff --git a/drivers/iio/common/ms_sensors/ms_sensors_i2c.c b/drivers/iio/common/ms_sensors/ms_sensors_i2c.c
> new file mode 100644
> index 0000000..4b1bc31
> --- /dev/null
> +++ b/drivers/iio/common/ms_sensors/ms_sensors_i2c.c
> @@ -0,0 +1,645 @@
> +/*
> + * Measurements Specialties driver common i2c functions
> + *
> + * Copyright (c) 2015 Measurement-Specialties
> + *
> + * Licensed under the GPL-2.
Drop this blank line.
> + *
> + */
> +
> +#include <linux/module.h>
> +#include <linux/iio/iio.h>
> +#include <linux/device.h>
> +#include <linux/delay.h>
> +
> +#include "ms_sensors_i2c.h"
> +
> +/* Conversion times in us */
> +static const u16 ms_sensors_ht_t_conversion_time[] = { 50000, 25000,
> + 13000, 7000 };
> +static const u16 ms_sensors_ht_h_conversion_time[] = { 16000, 3000,
> + 5000, 8000 };
> +static const u16 ms_sensors_tp_conversion_time[] = { 500, 1100, 2100,
> + 4100, 8220, 16440 };
> +
> +#define MS_SENSORS_SERIAL_READ_MSB 0xFA0F
> +#define MS_SENSORS_SERIAL_READ_LSB 0xFCC9
> +#define MS_SENSORS_CONFIG_REG_WRITE 0xE6
> +#define MS_SENSORS_CONFIG_REG_READ 0xE7
> +#define MS_SENSORS_HT_T_CONVERSION_START 0xF3
> +#define MS_SENSORS_HT_H_CONVERSION_START 0xF5
> +
> +#define MS_SENSORS_TP_PROM_READ 0xA0
> +#define MS_SENSORS_TP_T_CONVERSION_START 0x50
> +#define MS_SENSORS_TP_P_CONVERSION_START 0x40
> +#define MS_SENSORS_TP_ADC_READ 0x00
> +
> +#define MS_SENSORS_NO_READ_CMD 0xFF
> +
> +/**
> + * ms_sensors_i2c_reset() - i2c reset function
> + * @cli: pointer to i2c client
> + * @cmd: reset cmd. Depends on device in use
> + * @delay: usleep minimal delay after reset command is issued
> + *
> + * Generic I2C reset function for Measurement Specialties devices.
> + *
> + * Return: 0 on success, negative errno otherwise.
> + */
> +int ms_sensors_i2c_reset(void *cli, u8 cmd, unsigned int delay)
> +{
> + int ret;
> + struct i2c_client *client = cli;
> +
> + ret = i2c_smbus_write_byte(client, cmd);
> + if (ret) {
> + dev_err(&client->dev, "Failed to reset device\n");
> + return ret;
> + }
> + usleep_range(delay, delay + 1000);
> +
> + return 0;
> +}
> +EXPORT_SYMBOL(ms_sensors_i2c_reset);
> +
> +/**
> + * ms_sensors_i2c_read_prom_word() - i2c prom word read function
> + * @cli: pointer to i2c client
> + * @cmd: PROM read cmd. Depends on device and prom id
> + * @word: pointer to word destination value
> + *
> + * Generic i2c prom word read function for Measurement Specialties devices.
> + *
> + * Return: 0 on success, negative errno otherwise.
> + */
> +int ms_sensors_i2c_read_prom_word(void *cli, int cmd, u16 *word)
> +{
> + int ret;
> + struct i2c_client *client = (struct i2c_client *)cli;
Why pass an void * given the function name says this will always be an i2c_client?
Once that's removed this wrapper does very little and I'd be tempted to
drop it in favour of direct calls to the smbus read.
> +
> + ret = i2c_smbus_read_word_swapped(client, cmd);
> + if (ret < 0) {
> + dev_err(&client->dev, "Failed to read prom word\n");
> + return ret;
> + }
> + *word = ret;
> +
> + return 0;
> +}
> +EXPORT_SYMBOL(ms_sensors_i2c_read_prom_word);
> +
> +/**
> + * ms_sensors_i2c_convert_and_read() - i2c ADC conversion & read function
> + * @cli: pointer to i2c client
> + * @conv: ADC conversion command. Depends on device in use
> + * @rd: ADC read command. Depends on device in use
> + * @delay: usleep minimal delay after conversion command is issued
> + * @adc: pointer to ADC destination value
> + *
> + * Generic i2c ADC conversion & read function for Measurement Specialties
> + * devices.
> + * The function will issue conversion command, sleep appopriate delay, and
> + * issue command to read ADC.
> + *
> + * Return: 0 on success, negative errno otherwise.
> + */
> +int ms_sensors_i2c_convert_and_read(void *cli, u8 conv, u8 rd,
> + unsigned int delay, u32 *adc)
> +{
> + int ret;
> + u32 buf = 0;
> + struct i2c_client *client = (struct i2c_client *)cli;
> +
> + /* Trigger conversion */
> + ret = i2c_smbus_write_byte(client, conv);
> + if (ret)
> + goto err;
> + usleep_range(delay, delay + 1000);
> +
> + /* Retrieve ADC value */
> + if (rd != MS_SENSORS_NO_READ_CMD)
> + ret = i2c_smbus_read_i2c_block_data(client, rd, 3, (u8 *)&buf);
> + else
> + ret = i2c_master_recv(client, (u8 *)&buf, 3);
> + if (ret < 0)
> + goto err;
> +
> + dev_dbg(&client->dev, "ADC raw value : %x\n", be32_to_cpu(buf) >> 8);
> + *adc = be32_to_cpu(buf) >> 8;
> +
> + return 0;
> +err:
> + dev_err(&client->dev, "Unable to make sensor adc conversion\n");
> + return ret;
> +}
> +EXPORT_SYMBOL(ms_sensors_i2c_convert_and_read);
> +
> +/**
> + * ms_sensors_crc_valid() - CRC check function
> + * @value: input and CRC compare value
> + *
> + * Cyclic Redundancy Check function used in TSYS02D, HTU21, MS8607.
> + * This function performs a x^8 + x^5 + x^4 + 1 polynomial CRC.
> + * The argument contains CRC value in LSB byte while the bytes 1 and 2
> + * are used for CRC computation.
> + *
> + * Return: 1 if CRC is valid, 0 otherwise.
Can this be done with the standard kernel crc32 functions? (not dug into
it enough to be sure!)
> + */
> +static bool ms_sensors_crc_valid(u32 value)
> +{
> + u32 polynom = 0x988000; /* x^8 + x^5 + x^4 + 1 */
> + u32 msb = 0x800000;
> + u32 mask = 0xFF8000;
> + u32 result = value & 0xFFFF00;
> + u8 crc = value & 0xFF;
> +
> + while (msb != 0x80) {
> + if (result & msb)
> + result = ((result ^ polynom) & mask)
> + | (result & ~mask);
> + msb >>= 1;
> + mask >>= 1;
> + polynom >>= 1;
> + }
> +
> + return result == crc;
> +}
> +
> +/**
> + * ms_sensors_i2c_read_serial() - i2c serial number read function
> + * @cli: pointer to i2c client
> + * @sn: pointer to 64-bits destination value
> + *
> + * Generic i2c serial number read function for Measurement Specialties devices.
> + * This function is used for TSYS02d, HTU21, MS8607 chipset.
> + * Refer to datasheet:
> + * http://www.meas-spec.com/downloads/HTU2X_Serial_Number_Reading.pdf
THat's a first. A whole datasheet on how the heck the serial number works!
Got to wonder how anyone ever came up with that. I'm going to conclude
you got it right and not read any more ;)
> + *
> + * Return: 0 on success, negative errno otherwise.
> + */
> +int ms_sensors_i2c_read_serial(struct i2c_client *client, u64 *sn)
> +{
> + u8 i;
> + u64 rcv_buf = 0;
> + u16 send_buf;
> + int ret;
> +
> + struct i2c_msg msg[2] = {
> + {
> + .addr = client->addr,
> + .flags = client->flags,
> + .len = 2,
> + .buf = (__u8 *)&send_buf,
> + },
> + {
> + .addr = client->addr,
> + .flags = client->flags | I2C_M_RD,
> + .buf = (__u8 *)&rcv_buf,
> + },
> + };
> +
> + /* Read MSB part of serial number */
> + send_buf = cpu_to_be16(MS_SENSORS_SERIAL_READ_MSB);
> + msg[1].len = 8;
> + ret = i2c_transfer(client->adapter, msg, 2);
> + if (ret < 0) {
> + dev_err(&client->dev, "Unable to read device serial number");
> + return ret;
> + }
> +
> + rcv_buf = be64_to_cpu(rcv_buf);
> + dev_dbg(&client->dev, "Serial MSB raw : %llx\n", rcv_buf);
> +
> + for (i = 0; i < 64; i += 16) {
> + if (!ms_sensors_crc_valid((rcv_buf >> i) & 0xFFFF))
> + return -ENODEV;
> + }
> +
Umm. I'm really unclear what you are doing here. You read into
a 64 bit buffer, then do a hand endian swap and shift? Should be possible
to at least use standard functions to swap the byte order.
> + *sn = (((rcv_buf >> 32) & 0xFF000000) |
> + ((rcv_buf >> 24) & 0x00FF0000) |
> + ((rcv_buf >> 16) & 0x0000FF00) |
> + ((rcv_buf >> 8) & 0x000000FF)) << 16;
> +
> + /* Read LSB part of serial number */
> + send_buf = cpu_to_be16(MS_SENSORS_SERIAL_READ_LSB);
> + msg[1].len = 6;
> + rcv_buf = 0;
> + ret = i2c_transfer(client->adapter, msg, 2);
> + if (ret < 0) {
> + dev_err(&client->dev, "Unable to read device serial number");
> + return ret;
> + }
> +
> + rcv_buf = be64_to_cpu(rcv_buf) >> 16;
> + dev_dbg(&client->dev, "Serial MSB raw : %llx\n", rcv_buf);
> +
> + for (i = 0; i < 48; i += 24) {
> + if (!ms_sensors_crc_valid((rcv_buf >> i) & 0xFFFFFF))
> + return -ENODEV;
> + }
> +
> + *sn |= (rcv_buf & 0xFFFF00) << 40 | (rcv_buf >> 32);
> +
> + return 0;
> +}
> +EXPORT_SYMBOL(ms_sensors_i2c_read_serial);
> +
> +static int ms_sensors_i2c_read_config_reg(struct i2c_client *client,
> + u8 *config_reg)
> +{
> + int ret;
> +
> + ret = i2c_smbus_write_byte(client, MS_SENSORS_CONFIG_REG_READ);
> + if (ret) {
> + dev_err(&client->dev, "Unable to read config register");
> + return ret;
> + }
> +
> + ret = i2c_master_recv(client, config_reg, 1);
> + if (ret < 0) {
> + dev_err(&client->dev, "Unable to read config register");
> + return ret;
> + }
> + dev_dbg(&client->dev, "Config register :%x\n", *config_reg);
> +
> + return 0;
> +}
> +
> +/**
> + * ms_sensors_i2c_write_resolution() - set resolution i2c function
> + * @dev_data: pointer to temperature/humidity device data
> + * @i: resolution index to set
> + *
> + * This function will program the appropriate resolution based on the index
> + * provided when user space will set samp_freq channel.
> + * This function is used for TSYS02D, HTU21 and MS8607 chipsets.
> + *
> + * Return: 0 on success, negative errno otherwise.
> + */
> +ssize_t ms_sensors_i2c_write_resolution(struct ms_ht_dev *dev_data,
> + u8 i)
> +{
> + u8 config_reg;
> + int ret;
> +
> + ret = ms_sensors_i2c_read_config_reg(dev_data->client, &config_reg);
> + if (ret)
> + return ret;
> +
> + config_reg &= 0x7E;
> + config_reg |= ((i & 1) << 7) + ((i & 2) >> 1);
> +
> + return i2c_smbus_write_byte_data(dev_data->client,
> + MS_SENSORS_CONFIG_REG_WRITE,
> + config_reg);
> +}
> +EXPORT_SYMBOL(ms_sensors_i2c_write_resolution);
> +
> +/**
> + * ms_sensors_i2c_show_battery_low() - show device battery low indicator
> + * @dev_data: pointer to temperature/humidity device data
> + * @buf: pointer to char buffer to write result
> + *
> + * This function will read battery indicator value in the device and
> + * return 1 if the device voltage is below 2.25V.
> + * This function is used for TSYS02D, HTU21 and MS8607 chipsets.
> + *
> + * Return: length of sprintf on success, negative errno otherwise.
> + */
> +ssize_t ms_sensors_i2c_show_battery_low(struct ms_ht_dev *dev_data,
> + char *buf)
> +{
> + int ret;
> + u8 config_reg;
> +
> + mutex_lock(&dev_data->lock);
> + ret = ms_sensors_i2c_read_config_reg(dev_data->client, &config_reg);
> + mutex_unlock(&dev_data->lock);
> + if (ret)
> + return ret;
> +
> + return sprintf(buf, "%d\n", (config_reg & 0x40) >> 6);
> +}
> +EXPORT_SYMBOL(ms_sensors_i2c_show_battery_low);
> +
> +/**
> + * ms_sensors_i2c_show_heater() - show device heater
> + * @dev_data: pointer to temperature/humidity device data
> + * @buf: pointer to char buffer to write result
> + *
> + * This function will read heater enable value in the device and
> + * return 1 if the heater is enabled.
> + * This function is used for HTU21 and MS8607 chipsets.
> + *
> + * Return: length of sprintf on success, negative errno otherwise.
> + */
> +ssize_t ms_sensors_i2c_show_heater(struct ms_ht_dev *dev_data,
> + char *buf)
> +{
> + u8 config_reg;
> + int ret;
> +
> + mutex_lock(&dev_data->lock);
> + ret = ms_sensors_i2c_read_config_reg(dev_data->client, &config_reg);
> + mutex_unlock(&dev_data->lock);
> + if (ret)
> + return ret;
> +
> + return sprintf(buf, "%d\n", (config_reg & 0x4) >> 2);
> +}
> +EXPORT_SYMBOL(ms_sensors_i2c_show_heater);
> +
> +/**
> + * ms_sensors_i2c_write_heater() - write device heater
> + * @dev_data: pointer to temperature/humidity device data
> + * @buf: pointer to char buffer from user space
> + * @len: length of buf
> + *
> + * This function will write 1 or 0 value in the device
> + * to enable or disable heater.
> + * This function is used for HTU21 and MS8607 chipsets.
> + *
> + * Return: length of buffer, negative errno otherwise.
> + */
> +ssize_t ms_sensors_i2c_write_heater(struct ms_ht_dev *dev_data,
> + const char *buf, size_t len)
> +{
> + u8 val, config_reg;
> + int ret;
> +
> + ret = kstrtou8(buf, 10, &val);
> + if (ret)
> + return ret;
> +
> + if (val > 1)
> + return -EINVAL;
> +
> + mutex_lock(&dev_data->lock);
> + ret = ms_sensors_i2c_read_config_reg(dev_data->client, &config_reg);
> + if (ret) {
> + mutex_unlock(&dev_data->lock);
> + return ret;
> + }
> +
> + config_reg &= 0xFB;
> + config_reg |= val << 2;
> +
> + ret = i2c_smbus_write_byte_data(dev_data->client,
> + MS_SENSORS_CONFIG_REG_WRITE,
> + config_reg);
> + mutex_unlock(&dev_data->lock);
> + if (ret) {
> + dev_err(&dev_data->client->dev, "Unable to write config register\n");
> + return ret;
> + }
> +
> + return len;
> +}
> +EXPORT_SYMBOL(ms_sensors_i2c_write_heater);
> +
> +/**
> + * ms_sensors_i2c_ht_read_temperature() - i2c read temperature
> + * @dev_data: pointer to temperature/humidity device data
> + * @temperature:pointer to temperature destination value
> + *
> + * This function will get temperature ADC value from the device,
> + * check the CRC and compute the temperature value.
> + * This function is used for TSYS02D, HTU21 and MS8607 chipsets.
> + *
> + * Return: 0 on success, negative errno otherwise.
> + */
> +int ms_sensors_i2c_ht_read_temperature(struct ms_ht_dev *dev_data,
> + s32 *temperature)
> +{
> + int ret;
> + u32 adc;
> + u16 delay;
> +
> + mutex_lock(&dev_data->lock);
> + delay = ms_sensors_ht_t_conversion_time[dev_data->res_index];
> + ret = ms_sensors_i2c_convert_and_read(dev_data->client,
> + MS_SENSORS_HT_T_CONVERSION_START,
> + MS_SENSORS_NO_READ_CMD,
> + delay, &adc);
> + mutex_unlock(&dev_data->lock);
> + if (ret)
> + return ret;
> +
> + if (!ms_sensors_crc_valid(adc)) {
> + dev_err(&dev_data->client->dev,
> + "Temperature read crc check error\n");
> + return -ENODEV;
> + }
> +
> + /* Temperature algorithm */
> + *temperature = (((s64)(adc >> 8) * 175720) >> 16) - 46850;
> +
> + return 0;
> +}
> +EXPORT_SYMBOL(ms_sensors_i2c_ht_read_temperature);
> +
> +/**
> + * ms_sensors_i2c_ht_read_humidity() - i2c read humidity
> + * @dev_data: pointer to temperature/humidity device data
> + * @humidity: pointer to humidity destination value
> + *
> + * This function will get humidity ADC value from the device,
> + * check the CRC and compute the temperature value.
> + * This function is used for HTU21 and MS8607 chipsets.
> + *
> + * Return: 0 on success, negative errno otherwise.
> + */
> +int ms_sensors_i2c_ht_read_humidity(struct ms_ht_dev *dev_data,
> + u32 *humidity)
> +{
> + int ret;
> + u32 adc;
> + u16 delay;
> +
> + mutex_lock(&dev_data->lock);
> + delay = ms_sensors_ht_h_conversion_time[dev_data->res_index];
> + ret = ms_sensors_i2c_convert_and_read(dev_data->client,
> + MS_SENSORS_HT_H_CONVERSION_START,
> + MS_SENSORS_NO_READ_CMD,
> + delay, &adc);
> + mutex_unlock(&dev_data->lock);
> + if (ret)
> + return ret;
> +
> + if (!ms_sensors_crc_valid(adc)) {
> + dev_err(&dev_data->client->dev,
> + "Humidity read crc check error\n");
> + return -ENODEV;
> + }
> +
> + /* Humidity algorithm */
> + *humidity = (((s32)(adc >> 8) * 12500) >> 16) * 10 - 6000;
> + if (*humidity >= 100000)
> + *humidity = 100000;
> +
> + return 0;
> +}
> +EXPORT_SYMBOL(ms_sensors_i2c_ht_read_humidity);
> +
> +/**
> + * ms_sensors_tp_crc_valid() - CRC check function for
> + * Temperature and pressure devices.
> + * This function is only used when reading PROM coefficients
> + *
> + * @prom: pointer to PROM coefficients array
> + * @len: length of PROM coefficients array
> + *
> + * Return: True if CRC is ok.
> + */
> +static bool ms_sensors_tp_crc_valid(u16 *prom, u8 len)
> +{
> + unsigned int cnt, n_bit;
> + u16 n_rem = 0x0000, crc_read = prom[0], crc = (*prom & 0xF000) >> 12;
> +
> + prom[len - 1] = 0;
> + prom[0] &= 0x0FFF; /* Clear the CRC computation part */
> +
> + for (cnt = 0; cnt < len * 2; cnt++) {
> + if (cnt % 2 == 1)
> + n_rem ^= prom[cnt >> 1] & 0x00FF;
> + else
> + n_rem ^= prom[cnt >> 1] >> 8;
> +
> + for (n_bit = 8; n_bit > 0; n_bit--) {
> + if (n_rem & 0x8000)
> + n_rem = (n_rem << 1) ^ 0x3000;
> + else
> + n_rem <<= 1;
> + }
> + }
> + n_rem >>= 12;
> + prom[0] = crc_read;
> +
> + return n_rem == crc;
> +}
> +
> +/**
> + * ms_sensors_tp_read_prom() - prom coeff read function
> + * @dev_data: pointer to temperature/pressure device data
> + *
> + * This function will read prom coefficients and check CRC.
> + * This function is used for MS5637 and MS8607 chipsets.
> + *
> + * Return: 0 on success, negative errno otherwise.
> + */
> +int ms_sensors_tp_read_prom(struct ms_tp_dev *dev_data)
> +{
> + int i, ret;
> +
> + for (i = 0; i < MS_SENSORS_TP_PROM_WORDS_NB; i++) {
> + ret = ms_sensors_i2c_read_prom_word(
> + dev_data->client,
> + MS_SENSORS_TP_PROM_READ + (i << 1),
> + &dev_data->prom[i]);
> +
> + if (ret)
> + return ret;
> + }
> +
> + if (!ms_sensors_tp_crc_valid(dev_data->prom,
> + MS_SENSORS_TP_PROM_WORDS_NB + 1)) {
> + dev_err(&dev_data->client->dev,
> + "Calibration coefficients crc check error\n");
> + return -ENODEV;
> + }
> +
> + return 0;
> +}
> +EXPORT_SYMBOL(ms_sensors_tp_read_prom);
> +
> +/**
> + * ms_sensors_read_temp_and_pressure() - read temp and pressure
> + * @dev_data: pointer to temperature/pressure device data
> + * @temperature:pointer to temperature destination value
> + * @pressure: pointer to pressure destination value
> + *
> + * This function will read ADC and compute pressure and temperature value.
> + * This function is used for MS5637 and MS8607 chipsets.
> + *
> + * Return: 0 on success, negative errno otherwise.
> + */
> +int ms_sensors_read_temp_and_pressure(struct ms_tp_dev *dev_data,
> + int *temperature,
> + unsigned int *pressure)
> +{
> + int ret;
> + u32 t_adc, p_adc;
> + s32 dt, temp;
> + s64 off, sens, t2, off2, sens2;
> + u16 *prom = dev_data->prom, delay;
> + u8 i;
> +
> + mutex_lock(&dev_data->lock);
> + i = dev_data->res_index * 2;
This local variable seens rather unnecessary. Just put it inline in the
calls.
> + delay = ms_sensors_tp_conversion_time[dev_data->res_index];
> +
> + ret = ms_sensors_i2c_convert_and_read(
> + dev_data->client,
> + MS_SENSORS_TP_T_CONVERSION_START + i,
> + MS_SENSORS_TP_ADC_READ,
> + delay, &t_adc);
> + if (ret) {
> + mutex_unlock(&dev_data->lock);
> + return ret;
> + }
> +
> + ret = ms_sensors_i2c_convert_and_read(
> + dev_data->client,
> + MS_SENSORS_TP_P_CONVERSION_START + i,
> + MS_SENSORS_TP_ADC_READ,
> + delay, &p_adc);
> + mutex_unlock(&dev_data->lock);
> + if (ret)
> + return ret;
> +
> + dt = (s32)t_adc - (prom[5] << 8);
> +
> + /* Actual temperature = 2000 + dT * TEMPSENS */
> + temp = 2000 + (((s64)dt * prom[6]) >> 23);
> +
> + /* Second order temperature compensation */
> + if (temp < 2000) {
> + s64 tmp = (s64)temp - 2000;
> +
> + t2 = (3 * ((s64)dt * (s64)dt)) >> 33;
> + off2 = (61 * tmp * tmp) >> 4;
> + sens2 = (29 * tmp * tmp) >> 4;
> +
> + if (temp < -1500) {
> + s64 tmp = (s64)temp + 1500;
> +
> + off2 += 17 * tmp * tmp;
> + sens2 += 9 * tmp * tmp;
> + }
> + } else {
> + t2 = (5 * ((s64)dt * (s64)dt)) >> 38;
> + off2 = 0;
> + sens2 = 0;
> + }
> +
> + /* OFF = OFF_T1 + TCO * dT */
> + off = (((s64)prom[2]) << 17) + ((((s64)prom[4]) * (s64)dt) >> 6);
> + off -= off2;
> +
> + /* Sensitivity at actual temperature = SENS_T1 + TCS * dT */
> + sens = (((s64)prom[1]) << 16) + (((s64)prom[3] * dt) >> 7);
> + sens -= sens2;
> +
> + /* Temperature compensated pressure = D1 * SENS - OFF */
> + *temperature = (temp - t2) * 10;
> + *pressure = (u32)(((((s64)p_adc * sens) >> 21) - off) >> 15);
> +
> + return 0;
> +}
> +EXPORT_SYMBOL(ms_sensors_read_temp_and_pressure);
> +
> +MODULE_DESCRIPTION("Measurement-Specialties common i2c driver");
> +MODULE_AUTHOR("William Markezana <william.markezana@xxxxxxxxxxxxx>");
> +MODULE_AUTHOR("Ludovic Tancerel <ludovic.tancerel@xxxxxxxxxxxxxxxxx>");
> +MODULE_LICENSE("GPL v2");
> +
> diff --git a/drivers/iio/common/ms_sensors/ms_sensors_i2c.h b/drivers/iio/common/ms_sensors/ms_sensors_i2c.h
> new file mode 100644
> index 0000000..918b8af
> --- /dev/null
> +++ b/drivers/iio/common/ms_sensors/ms_sensors_i2c.h
> @@ -0,0 +1,53 @@
> +/*
> + * Measurements Specialties common sensor driver
> + *
> + * Copyright (c) 2015 Measurement-Specialties
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + */
> +
> +#ifndef _MS_SENSORS_I2C_H
> +#define _MS_SENSORS_I2C_H
> +
> +#include <linux/i2c.h>
> +#include <linux/mutex.h>
> +
> +#define MS_SENSORS_TP_PROM_WORDS_NB 7
> +
> +struct ms_ht_dev {
> + struct i2c_client *client;
> + struct mutex lock; /* mutex protecting data structure */
> + u8 res_index;
> +};
> +
kernel doc comments preferred.
> +struct ms_tp_dev {
> + struct i2c_client *client;
> + struct mutex lock; /* mutex protecting data structure */
> + /* Added element for CRC computation */
> + u16 prom[MS_SENSORS_TP_PROM_WORDS_NB + 1];
> + u8 res_index;
> +};
> +
> +int ms_sensors_i2c_reset(void *cli, u8 cmd, unsigned int delay);
> +int ms_sensors_i2c_read_prom_word(void *cli, int cmd, u16 *word);
> +int ms_sensors_i2c_convert_and_read(void *cli, u8 conv, u8 rd,
> + unsigned int delay, u32 *adc);
> +int ms_sensors_i2c_read_serial(struct i2c_client *client, u64 *sn);
> +ssize_t ms_sensors_i2c_show_serial(struct ms_ht_dev *dev_data, char *buf);
> +ssize_t ms_sensors_i2c_write_resolution(struct ms_ht_dev *dev_data, u8 i);
> +ssize_t ms_sensors_i2c_show_battery_low(struct ms_ht_dev *dev_data, char *buf);
> +ssize_t ms_sensors_i2c_show_heater(struct ms_ht_dev *dev_data, char *buf);
> +ssize_t ms_sensors_i2c_write_heater(struct ms_ht_dev *dev_data,
> + const char *buf, size_t len);
> +int ms_sensors_i2c_ht_read_temperature(struct ms_ht_dev *dev_data,
> + s32 *temperature);
> +int ms_sensors_i2c_ht_read_humidity(struct ms_ht_dev *dev_data,
> + u32 *humidity);
> +int ms_sensors_tp_read_prom(struct ms_tp_dev *dev_data);
> +int ms_sensors_read_temp_and_pressure(struct ms_tp_dev *dev_data,
> + int *temperature,
> + unsigned int *pressure);
The presence or absense of _i2c in the function naming does feel rather
random. All of these functions ultimately make i2c calls so perhaps you
can explain your reasoning behind having it in some and not others.
> +
> +#endif /* _MS_SENSORS_I2C_H */
>
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