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/*
* Copyright (c) 2016-2016 Chris Johns <chrisj@rtems.org>
* All rights reserved.
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.rtems.org/license/LICENSE.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <unistd.h>
#include <dev/i2c/i2c.h>
#include <dev/i2c/ti-ads-16bit-adc.h>
/*
* Registers.
*/
#define ADS_CONVERSION (0)
#define ADS_CONFIG (1)
#define ADS_LO_THRESH (2)
#define ADS_HI_THRESH (3)
/*
* Configuration register.
*/
#define CFG_OS_NOT_CONVERTING (1 << 15) /* read */
#define CFG_OS_START_SSHOT (1 << 15) /* write */
#define CFG_MUX_BASE (12)
#define CFG_MUX_MASK (7)
#define CFG_PGA_BASE (9)
#define CFG_PGA_MASK (7)
#define CFG_MODE_BASE (8)
#define CFG_MODE_MASK (1)
#define CFG_DATA_RATE_BASE (5)
#define CFG_DATA_RATE_MASK (7)
#define CFG_COMP_BASE (0)
#define CFG_COMP_MASK (0x1f)
#define CFG_COMP_MODE_ACTIVE_LOW (0 << 4)
#define CFG_COMP_MODE_ACTIVE_HIGH (1 << 4)
#define CFG_MODE_CONT (0 << CFG_MODE_BASE)
#define CFG_MODE_SSHOT (1 << CFG_MODE_BASE)
typedef struct {
i2c_dev base;
ti_ads_adc device;
uint32_t poll_wait_period;
int reg;
uint16_t config_shadow;
} ti_ads;
static int
ti_ads_reg_write(ti_ads* dev, int reg, uint16_t value)
{
uint8_t out[3];
i2c_msg msgs[1] = {
{
.addr = dev->base.address,
.flags = 0,
.len = (uint16_t) sizeof(out),
.buf = &out[0]
}
};
out[0] = (uint8_t) reg;
out[1] = (uint8_t) (value >> 8);
out[2] = (uint8_t) value;
return i2c_bus_transfer(dev->base.bus, &msgs[0], RTEMS_ARRAY_SIZE(msgs));
}
static int
ti_ads_reg_read(ti_ads* dev, int reg, uint16_t* value)
{
uint8_t in[2] = { 0, 0 };
uint8_t out[1] = { (uint8_t) reg };
i2c_msg msgs[2] = {
{
.addr = dev->base.address,
.flags = 0,
.len = (uint16_t) sizeof(out),
.buf = &out[0]
}, {
.addr = dev->base.address,
.flags = I2C_M_RD,
.len = (uint16_t) sizeof(in),
.buf = &in[0]
}
};
int err;
err = i2c_bus_transfer(dev->base.bus, &msgs[0], RTEMS_ARRAY_SIZE(msgs));
*value = (((uint16_t) in[0]) << 8) | in[1];
return err;
}
static int
ti_ads_set_config(ti_ads* dev, uint16_t value, int base, uint16_t mask)
{
int err;
dev->config_shadow &= ~(mask << base);
dev->config_shadow |= (value & mask) << base;
err = ti_ads_reg_write(dev, ADS_CONFIG, dev->config_shadow);
return err;
}
static int
ti_ads_sample(ti_ads* dev, uint16_t* value)
{
int err;
if ((dev->config_shadow & CFG_MODE_SSHOT) == CFG_MODE_SSHOT) {
i2c_bus_obtain(dev->base.bus);
err = ti_ads_reg_write(dev,
ADS_CONFIG,
dev->config_shadow | CFG_OS_START_SSHOT);
if (err == 0) {
uint16_t config = 0;
while (err == 0 && (config & CFG_OS_NOT_CONVERTING) == 0) {
err = ti_ads_reg_read(dev, ADS_CONFIG, &config);
if (dev->poll_wait_period && (config & CFG_OS_NOT_CONVERTING) == 0)
usleep(dev->poll_wait_period);
}
err = ti_ads_reg_read(dev, ADS_CONVERSION, value);
}
i2c_bus_release(dev->base.bus);
}
else {
err = ti_ads_reg_read(dev, ADS_CONVERSION, value);
}
return err;
}
static int
ti_ads_ioctl(i2c_dev* iic_dev, ioctl_command_t command, void* arg)
{
ti_ads* dev = (ti_ads*) iic_dev;
uint16_t value;
int err;
switch (command) {
case TI_ADS_ADC_GET_CONVERSION:
value = 0;
err = ti_ads_sample(dev, &value);
if (err == 0)
*((uint16_t*) arg) = value;
break;
case TI_ADS_ADC_SET_MUX:
if (dev->device == TI_ADS1115) {
value = (uint16_t)(uintptr_t) arg;
err = ti_ads_set_config(dev, value, CFG_MUX_BASE, CFG_MUX_MASK);
}
else {
err = -ENOTTY;
}
break;
case TI_ADS_ADC_SET_MODE:
value = (uint16_t)(uintptr_t) arg;
err = ti_ads_set_config(dev, value, CFG_MODE_BASE, CFG_MODE_MASK);
break;
case TI_ADS_ADC_SET_PGA:
if (dev->device == TI_ADS1114 || dev->device == TI_ADS1115) {
value = (uint16_t)(uintptr_t) arg;
err = ti_ads_set_config(dev, value, CFG_PGA_BASE, CFG_PGA_MASK);
}
else {
err = -ENOTTY;
}
break;
case TI_ADS_ADC_SET_COMP:
if (dev->device == TI_ADS1114 || dev->device == TI_ADS1115) {
value = (uint16_t)(uintptr_t) arg;
err = ti_ads_set_config(dev, value, CFG_COMP_BASE, CFG_COMP_MASK);
}
else {
err = -ENOTTY;
}
break;
case TI_ADS_ADC_SET_LO_THRESH:
value = (uint16_t)(uintptr_t) arg;
err = ti_ads_reg_write(dev, ADS_LO_THRESH, value);
break;
case TI_ADS_ADC_SET_HI_THRESH:
value = (uint16_t)(uintptr_t) arg;
err = ti_ads_reg_write(dev, ADS_HI_THRESH, value);
break;
case TI_ADS_ADC_SET_CONV_WAIT:
dev->poll_wait_period = (uint32_t)(uintptr_t) arg;
err = 0;
break;
default:
err = -ENOTTY;
break;
}
return err;
}
int
i2c_dev_register_ti_ads_adc(const char* bus_path,
const char* dev_path,
uint16_t address,
ti_ads_adc device)
{
ti_ads* dev;
dev = (ti_ads*)
i2c_dev_alloc_and_init(sizeof(*dev), bus_path, address);
if (dev == NULL) {
return -1;
}
dev->base.ioctl = ti_ads_ioctl;
dev->device = device;
dev->config_shadow = 0;
switch (device) {
default:
errno = EIO;
return -1;
case TI_ADS1115:
dev->config_shadow |= ((TI_ADS_MUX_ApA0_AnA1 << CFG_MUX_BASE) |
(TI_ADS_PGA_FS_2_048V << CFG_PGA_BASE) |
((TI_ADS_COMP_MODE_HYSTERESIS |
TI_ADS_COMP_POL_ACTIVE_LOW |
TI_ADS_COMP_LAT_NON_LATCHING |
TI_ADS_COMP_QUE_DISABLE_COMP) << CFG_COMP_BASE));
/* FALLTHRU */
case TI_ADS1114:
dev->config_shadow |= TI_ADS_PGA_FS_2_048V << CFG_PGA_BASE;
/* FALLTHRU */
case TI_ADS1113:
dev->config_shadow |= (CFG_MODE_SSHOT |
(TI_ADS_DATARATE_8SPS << CFG_DATA_RATE_BASE));
break;
}
return i2c_dev_register(&dev->base, dev_path);
}
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