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incubator-nuttx/drivers/sensors/as5048a.c

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/****************************************************************************
* drivers/sensors/as5048a.c
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <assert.h>
#include <errno.h>
#include <debug.h>
#include <stdlib.h>
#include <nuttx/kmalloc.h>
#include <nuttx/fs/fs.h>
#include <nuttx/spi/spi.h>
#include <nuttx/sensors/as5048a.h>
#if defined(CONFIG_SENSORS_AS5048A)
/****************************************************************************
* Private Types
****************************************************************************/
struct as5048a_dev_s
{
struct qe_lowerhalf_s lower; /* AS5048A quadrature encoder lower half */
FAR struct spi_dev_s *spi; /* SPI interface */
/* Since multiple AS5048A can be connected to the same SPI bus we need
* to use multiple spi device ids which are employed by NuttX to select/
* deselect the desired AS5048A chip via their chip select inputs.
*/
int spi_devid;
};
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
static int as5048a_writeu16(FAR struct as5048a_dev_s *priv,
uint16_t regaddr, uint16_t regval);
static int as5048a_exchange(FAR struct as5048a_dev_s *priv,
uint16_t regaddr, FAR uint16_t *regval);
static uint16_t calc_even_parity(uint16_t value);
static int as5048a_readzero(FAR struct as5048a_dev_s *priv,
FAR uint16_t *zero);
static int as5048a_writezero(FAR struct as5048a_dev_s *priv, uint16_t zero);
static int as5048a_readagc(FAR struct as5048a_dev_s *priv,
FAR uint16_t *agc);
static int as5048a_readdiag(FAR struct as5048a_dev_s *priv,
FAR uint16_t *diag);
static int as5048a_readmag(FAR struct as5048a_dev_s *priv,
FAR uint16_t *mag);
static int as5048a_readang(FAR struct as5048a_dev_s *priv,
FAR uint16_t *ang);
/* Character Driver Methods */
static int as5048a_setup(FAR struct qe_lowerhalf_s *lower);
static int as5048a_shutdown(FAR struct qe_lowerhalf_s *lower);
static int as5048a_position(FAR struct qe_lowerhalf_s *lower,
FAR int32_t *pos);
static int as5048a_reset(FAR struct qe_lowerhalf_s *lower);
static int as5048a_ioctl(FAR struct qe_lowerhalf_s *lower, int cmd,
unsigned long arg);
/****************************************************************************
* Private Data
****************************************************************************/
static const struct qe_ops_s g_qeops =
{
as5048a_setup, /* setup */
as5048a_shutdown, /* shutdown */
as5048a_position, /* position */
NULL, /* setposmax */
as5048a_reset, /* reset */
NULL, /* setindex */
as5048a_ioctl /* ioctl */
};
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: as5048a_configspi
*
* Description:
*
****************************************************************************/
static inline void as5048a_configspi(FAR struct spi_dev_s *spi)
{
/* Configure SPI for the AS5048A */
SPI_SETMODE(spi, AS5048A_SPI_MODE);
SPI_SETBITS(spi, 16);
SPI_HWFEATURES(spi, 0);
SPI_SETFREQUENCY(spi, AS5048A_SPI_MAXFREQUENCY);
}
/****************************************************************************
* Name: as5048a_writeu16
*
* Description:
* Write to two 8-bit registers
*
****************************************************************************/
static int as5048a_writeu16(FAR struct as5048a_dev_s *priv,
uint16_t regaddr, uint16_t regval)
{
uint16_t datout;
/* If SPI bus is shared then lock and configure it */
SPI_LOCK(priv->spi, true);
as5048a_configspi(priv->spi);
/* Select the AS5048A */
SPI_SELECT(priv->spi, priv->spi_devid, true);
/* Send register address and set the value */
datout = AS5048A_CMD_WRITE | regaddr;
datout |= calc_even_parity(datout) << 15;
SPI_SEND(priv->spi, datout);
datout = 0x3fff & regval;
datout |= calc_even_parity(datout) << 15;
SPI_SEND(priv->spi, datout);
/* Send NOP command */
SPI_SEND(priv->spi, 0x0000);
/* Deselect the AS5048A */
SPI_SELECT(priv->spi, priv->spi_devid, false);
/* Unlock bus */
SPI_LOCK(priv->spi, false);
return OK;
}
/****************************************************************************
* Name: as5048a_exchange
*
* Description:
* Read from 16-bit registers
*
****************************************************************************/
static int as5048a_exchange(FAR struct as5048a_dev_s *priv,
uint16_t regaddr, FAR uint16_t *regval)
{
uint16_t ret;
uint16_t dat;
uint16_t temp;
/* If SPI bus is shared then lock and configure it */
SPI_LOCK(priv->spi, true);
as5048a_configspi(priv->spi);
/* Select the AS5048A */
SPI_SELECT(priv->spi, priv->spi_devid, true);
/* Send READ command. Received data is thrown away
* this data comes from the previous command (unknown)
*/
dat = AS5048A_CMD_READ | regaddr;
dat |= calc_even_parity(dat) << 15;
/* Send register to read and get the next byte */
SPI_SEND(priv->spi, dat);
/* Send NOP command. Received data is the value of regaddr
* from the previous command
*/
dat = 0x0000; /* NOP command */
temp = SPI_SEND(priv->spi, dat);
if (temp & 0x4000)
{
/* error flag set - need to reset it */
dat = AS5048A_CMD_READ | AS5048A_CLRERR_REG;
dat |= calc_even_parity(dat) << 15;
SPI_SEND(priv->spi, dat);
snerr("ERROR: as5048a error flag set, need to reset it! %02x\n", temp);
ret = -1;
}
else
{
*regval = temp;
ret = 0;
}
/* Deselect the AS5048A */
SPI_SELECT(priv->spi, priv->spi_devid, false);
/* Unlock bus */
SPI_LOCK(priv->spi, false);
sninfo("addr: %02x value: %02x ret: %d\n", regaddr, *regval, ret);
return ret;
}
/****************************************************************************
* Name: calc_even_parity
*
* Description:
* get the even parity of input value
*
****************************************************************************/
static uint16_t calc_even_parity(uint16_t value)
{
uint16_t cnt = 0;
uint8_t i;
for (i = 0; i < 16; i++)
{
if (value & 0x1) cnt++;
value >>= 1;
}
return cnt & 0x1;
}
/****************************************************************************
* Name: as5048a_readzero
*
* Description:
* Read from the zero position registers
*
****************************************************************************/
static int as5048a_readzero(FAR struct as5048a_dev_s *priv,
FAR uint16_t *zero)
{
uint16_t hi;
uint16_t lo;
int ret;
/* Read the high 8 bits of the 13-bit value */
ret = as5048a_exchange(priv, AS5048A_ZEROHI_REG, &hi);
if (ret < 0)
{
snerr("ERROR: as5048a_readu8 failed: %d\n", ret);
return ret;
}
/* Read the low 5 bits of the 13-bit value */
ret = as5048a_exchange(priv, AS5048A_ZEROLO_REG, &lo);
if (ret < 0)
{
snerr("ERROR: as5048a_readu8 failed: %d\n", ret);
return ret;
}
*zero = (uint16_t)hi << 6 | (uint16_t)lo;
sninfo("zero: %04x ret: %d\n", *zero, ret);
return ret;
}
/****************************************************************************
* Name: as5048a_writezero
*
* Description:
* Write to the zero position registers
*
****************************************************************************/
static int as5048a_writezero(FAR struct as5048a_dev_s *priv, uint16_t zero)
{
int ret;
sninfo("zero: %04x\n", zero);
ret = as5048a_writeu16(priv, AS5048A_ZEROHI_REG, (zero >> 6));
if (ret < 0)
{
snerr("ERROR: as5048a_writeu16 failed: %d\n", ret);
}
ret = as5048a_writeu16(priv, AS5048A_ZEROLO_REG, zero);
if (ret < 0)
{
snerr("ERROR: as5048a_writeu16 failed: %d\n", ret);
}
return ret;
}
/****************************************************************************
* Name: as5048a_readagc
*
* Description:
* Read from the automatic gain control register
*
****************************************************************************/
static int as5048a_readagc(FAR struct as5048a_dev_s *priv, FAR uint16_t *agc)
{
int ret;
ret = as5048a_exchange(priv, AS5048A_AGC_REG, agc);
if (ret < 0)
{
snerr("ERROR: as5048a_exchange failed: %d\n", ret);
return ret;
}
sninfo("agc: %02x ret: %d\n", *agc, ret);
return ret;
}
/****************************************************************************
* Name: as5048a_readdiag
*
* Description:
* Read from the diagnostics register
*
****************************************************************************/
static int as5048a_readdiag(FAR struct as5048a_dev_s *priv,
FAR uint16_t *diag)
{
int ret;
ret = as5048a_exchange(priv, AS5048A_DIAG_REG, diag);
if (ret < 0)
{
snerr("ERROR: as5048a_exchange failed: %d\n", ret);
return ret;
}
sninfo("diag: %02x ret: %d\n", *diag, ret);
return ret;
}
/****************************************************************************
* Name: as5048a_readmag
*
* Description:
* Read from the magnitude registers
*
****************************************************************************/
static int as5048a_readmag(FAR struct as5048a_dev_s *priv, FAR uint16_t *mag)
{
int ret;
ret = as5048a_exchange(priv, AS5048A_MAG_REG, mag);
if (ret < 0)
{
snerr("ERROR: as5048a_exchange failed: %d\n", ret);
return ret;
}
sninfo("mag: %04x ret: %d\n", *mag, ret);
return ret;
}
/****************************************************************************
* Name: as5048a_readang
*
* Description:
* Read from the angle registers
*
****************************************************************************/
static int as5048a_readang(FAR struct as5048a_dev_s *priv, FAR uint16_t *ang)
{
int ret;
ret = as5048a_exchange(priv, AS5048A_ANGLE_REG, ang);
if (ret < 0)
{
snerr("ERROR: as5048a_exchange failed: %d\n", ret);
return ret;
}
sninfo("ang: %04x ret: %d\n", *ang, ret);
return ret;
}
/****************************************************************************
* Name: as5048a_setup
*
* Description:
* This method is called when the driver is opened
*
****************************************************************************/
static int as5048a_setup(FAR struct qe_lowerhalf_s *lower)
{
return OK;
}
/****************************************************************************
* Name: as5048a_shutdown
*
* Description:
* This method is called when the driver is closed
*
****************************************************************************/
static int as5048a_shutdown(FAR struct qe_lowerhalf_s *lower)
{
return OK;
}
/****************************************************************************
* Name: as5048a_position
*
* Description:
* Return the current position measurement
*
****************************************************************************/
static int as5048a_position(FAR struct qe_lowerhalf_s *lower,
FAR int32_t *pos)
{
FAR struct as5048a_dev_s *priv = (FAR struct as5048a_dev_s *)lower;
uint16_t ang;
int ret;
ret = as5048a_readang(priv, &ang);
if (ret < 0)
{
snerr("ERROR: as5048a_readang failed: %d\n", ret);
return ret;
}
*pos = (int32_t)ang;
return ret;
}
/****************************************************************************
* Name: as5048a_reset
*
* Description:
* Reset the position measurement to zero
*
****************************************************************************/
static int as5048a_reset(FAR struct qe_lowerhalf_s *lower)
{
FAR struct as5048a_dev_s *priv = (FAR struct as5048a_dev_s *)lower;
uint16_t ang;
int ret;
ret = as5048a_writezero(priv, 0);
if (ret < 0)
{
snerr("ERROR: as5048a_writezero failed: %d\n", ret);
return ret;
}
ret = as5048a_readang(priv, &ang);
if (ret < 0)
{
snerr("ERROR: as5048a_readang failed: %d\n", ret);
return ret;
}
ret = as5048a_writezero(priv, ang);
if (ret < 0)
{
snerr("ERROR: as5048a_writezero failed: %d\n", ret);
}
return ret;
}
/****************************************************************************
* Name: as5048a_ioctl
****************************************************************************/
static int as5048a_ioctl(FAR struct qe_lowerhalf_s *lower, int cmd,
unsigned long arg)
{
FAR struct as5048a_dev_s *priv = (FAR struct as5048a_dev_s *)lower;
int ret = OK;
switch (cmd)
{
/* Read from the zero position registers. Arg: int* pointer. */
case QEIOC_AS5048A_ZEROPOSITION:
{
FAR int *ptr = (FAR int *)((uintptr_t)arg);
uint16_t zero;
DEBUGASSERT(ptr != NULL);
ret = as5048a_readzero(priv, &zero);
if (ret == OK)
{
*ptr = (int)zero;
}
sninfo("zero: %04x ret: %d\n", *ptr, ret);
}
break;
/* Read from the automatic gain control register */
case QEIOC_AS5048A_AUTOGAINCTL:
{
FAR uint16_t *ptr = (FAR uint16_t *)((uintptr_t)arg);
DEBUGASSERT(ptr != NULL);
ret = as5048a_readagc(priv, ptr);
sninfo("agc: %02x ret: %d\n", *ptr, ret);
}
break;
/* Read from the diagnostics register. Arg: uint8_t* pointer. */
case QEIOC_AS5048A_DIAGNOSTICS:
{
FAR uint16_t *ptr = (FAR uint16_t *)((uintptr_t)arg);
DEBUGASSERT(ptr != NULL);
ret = as5048a_readdiag(priv, ptr);
sninfo("diag: %02x ret: %d\n", *ptr, ret);
}
break;
/* Read from the magnitude registers. Arg: int* pointer. */
case QEIOC_AS5048A_MAGNITUDE:
{
FAR int *ptr = (FAR int *)((uintptr_t)arg);
uint16_t mag;
DEBUGASSERT(ptr != NULL);
ret = as5048a_readmag(priv, &mag);
if (ret == OK)
{
*ptr = (int)mag;
}
sninfo("mag: %04x ret: %d\n", *ptr, ret);
}
break;
default:
snerr("ERROR: Unrecognized cmd: %d arg: %ld\n", cmd, arg);
ret = -ENOTTY;
break;
}
return ret;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: as5048a_initialize
*
* Description:
* Initialize the AS5048A device.
*
* Input Parameters:
* spi - An SPI driver instance.
*
* Returned Value:
* A new lower half encoder interface for the AS5048A on success;
* NULL on failure.
*
****************************************************************************/
FAR struct qe_lowerhalf_s *as5048a_initialize(FAR struct spi_dev_s *spi,
int spi_devid)
{
FAR struct as5048a_dev_s *priv;
DEBUGASSERT(spi != NULL);
/* Initialize the device's structure */
priv = (FAR struct as5048a_dev_s *)kmm_malloc(sizeof(*priv));
if (priv == NULL)
{
snerr("ERROR: Failed to allocate instance\n");
return NULL;
}
priv->lower.ops = &g_qeops;
priv->spi = spi;
priv->spi_devid = spi_devid;
return &priv->lower;
}
#endif /* CONFIG_SENSORS_AS5048A */
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