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walnux/arch/mips/src/pic32mx/pic32mx-spi.c
Gregory Nutt 3a74a438d9 Rename CONFIG_DEBUG_VERBOSE to CONFIG_DEBUG_INFO
2016-06-11 11:50:18 -06:00

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/****************************************************************************
* arch/mips/src/pic32mx/pic32mx-spi.c
*
* Copyright (C) 2012, 2015-2016 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sys/types.h>
#include <stdint.h>
#include <stdbool.h>
#include <semaphore.h>
#include <errno.h>
#include <debug.h>
#include <arch/board/board.h>
#include <nuttx/irq.h>
#include <nuttx/arch.h>
#include <nuttx/spi/spi.h>
#include "up_internal.h"
#include "up_arch.h"
#include "chip.h"
#include "pic32mx.h"
#include "pic32mx-spi.h"
#if defined(CONFIG_PIC32MX_SPI1) || defined(CONFIG_PIC32MX_SPI2) || \
defined(CONFIG_PIC32MX_SPI3) || defined(CONFIG_PIC32MX_SPI4)
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* Configuration */
#ifdef CONFIG_SPI_EXCHANGE
/* See arch/mips/src/pic32mz/pic32mz-spi.c for an implementation */
# error CONFIG_SPI_EXCHANGE not supported by this driver
#endif
/* Debug */
#ifdef CONFIG_DEBUG_SPI
# define spidbg lldbg
# ifdef CONFIG_DEBUG_INFO
# define spivdbg lldbg
# else
# define spivdbg(x...)
# endif
#else
# define spidbg(x...)
# define spivdbg(x...)
#endif
/****************************************************************************
* Private Types
****************************************************************************/
/* This structure describes the state of the SSP driver */
struct pic32mx_dev_s
{
struct spi_dev_s spidev; /* Externally visible part of the SPI interface */
uint32_t base; /* SPI register base address */
#ifdef CONFIG_PIC32MX_SPI_INTERRUPTS
uint8_t vector; /* Interrupt vector number(for attaching) */
uint8_t eirq; /* SPI fault interrupt number */
uint8_t rxirq; /* SPI receive done interrupt number */
uint8_t txirq; /* SPI transfer done interrupt number */
#endif
sem_t exclsem; /* Held while chip is selected for mutual exclusion */
uint32_t frequency; /* Requested clock frequency */
uint32_t actual; /* Actual clock frequency */
uint8_t nbits; /* Width of word in bits (8 to 16) */
uint8_t mode; /* Mode 0,1,2,3 */
};
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
/* Low-level register access */
static uint32_t spi_getreg(FAR struct pic32mx_dev_s *priv,
unsigned int offset);
static void spi_putreg(FAR struct pic32mx_dev_s *priv,
unsigned int offset, uint32_t value);
/* SPI methods */
static int spi_lock(FAR struct spi_dev_s *dev, bool lock);
static uint32_t spi_setfrequency(FAR struct spi_dev_s *dev, uint32_t frequency);
static void spi_setmode(FAR struct spi_dev_s *dev, enum spi_mode_e mode);
static void spi_setbits(FAR struct spi_dev_s *dev, int nbits);
static uint16_t spi_send(FAR struct spi_dev_s *dev, uint16_t ch);
static void spi_sndblock(FAR struct spi_dev_s *dev, FAR const void *buffer, size_t nwords);
static void spi_recvblock(FAR struct spi_dev_s *dev, FAR void *buffer, size_t nwords);
/****************************************************************************
* Private Data
****************************************************************************/
#ifdef CONFIG_PIC32MX_SPI1
static const struct spi_ops_s g_spi1ops =
{
.lock = spi_lock,
.select = pic32mx_spi1select,
.setfrequency = spi_setfrequency,
.setmode = spi_setmode,
.setbits = spi_setbits,
#ifdef CONFIG_SPI_HWFEATURES
.hwfeatures = 0, /* Not supported */
#endif
.status = pic32mx_spi1status,
#ifdef CONFIG_SPI_CMDDATA
.cmddata = pic32mx_spi1cmddata,
#endif
.send = spi_send,
.sndblock = spi_sndblock,
.recvblock = spi_recvblock,
#ifdef CONFIG_SPI_CALLBACK
.registercallback = pic32mx_spi1register, /* Provided externally */
#else
.registercallback = 0, /* Not implemented */
#endif
};
static struct pic32mx_dev_s g_spi1dev =
{
.spidev = { &g_spi1ops },
.base = PIC32MX_SPI1_K1BASE,
#ifdef CONFIG_PIC32MX_SPI_INTERRUPTS
.vector = PIC32MX_IRQ_SPI1,
.eirq = PIC32MX_IRQSRC_SPI1E,
.rxirq = PIC32MX_IRQSRC_SPI1RX,
.txirq = PIC32MX_IRQSRC_SPI1TX,
#endif
};
#endif
#ifdef CONFIG_PIC32MX_SPI2
static const struct spi_ops_s g_spi2ops =
{
.lock = spi_lock,
.select = pic32mx_spi2select,
.setfrequency = spi_setfrequency,
.setmode = spi_setmode,
.setbits = spi_setbits,
.status = pic32mx_spi2status,
#ifdef CONFIG_SPI_CMDDATA
.cmddata = pic32mx_spi2cmddata,
#endif
.send = spi_send,
.sndblock = spi_sndblock,
.recvblock = spi_recvblock,
#ifdef CONFIG_SPI_CALLBACK
.registercallback = pic32mx_spi2register, /* Provided externally */
#else
.registercallback = 0, /* Not implemented */
#endif
};
static struct pic32mx_dev_s g_spi2dev =
{
.spidev = { &g_spi2ops },
.base = PIC32MX_SPI2_K1BASE,
#ifdef CONFIG_PIC32MX_SPI_INTERRUPTS
.vector = PIC32MX_IRQ_SPI2,
.eirq = PIC32MX_IRQSRC_SPI2E,
.rxirq = PIC32MX_IRQSRC_SPI2RX,
.txirq = PIC32MX_IRQSRC_SPI2TX,
#endif
};
#endif
#ifdef CONFIG_PIC32MX_SPI3
static const struct spi_ops_s g_spi3ops =
{
.lock = spi_lock,
.select = pic32mx_spi3select,
.setfrequency = spi_setfrequency,
.setmode = spi_setmode,
.setbits = spi_setbits,
.status = pic32mx_spi3status,
#ifdef CONFIG_SPI_CMDDATA
.cmddata = pic32mx_spi3cmddata,
#endif
.send = spi_send,
.sndblock = spi_sndblock,
.recvblock = spi_recvblock,
#ifdef CONFIG_SPI_CALLBACK
.registercallback = pic32mx_spi3register, /* Provided externally */
#else
.registercallback = 0, /* Not implemented */
#endif
};
static struct pic32mx_dev_s g_spi3dev =
{
.spidev = { &g_spi3ops },
.base = PIC32MX_SPI3_K1BASE,
#ifdef CONFIG_PIC32MX_SPI_INTERRUPTS
.vector = PIC32MX_IRQ_SPI4,
.eirq = PIC32MX_IRQSRC_SPI3E,
.rxirq = PIC32MX_IRQSRC_SPI3RX,
.txirq = PIC32MX_IRQSRC_SPI3TX,
#endif
};
#endif
#ifdef CONFIG_PIC32MX_SPI4
static const struct spi_ops_s g_spi4ops =
{
.lock = spi_lock,
.select = pic32mx_spi4select,
.setfrequency = spi_setfrequency,
.setmode = spi_setmode,
.setbits = spi_setbits,
.status = pic32mx_spi4status,
#ifdef CONFIG_SPI_CMDDATA
.cmddata = pic32mx_spi4cmddata,
#endif
.send = spi_send,
.sndblock = spi_sndblock,
.recvblock = spi_recvblock,
#ifdef CONFIG_SPI_CALLBACK
.registercallback = pic32mx_spi4register, /* Provided externally */
#else
.registercallback = 0, /* Not implemented */
#endif
};
static struct pic32mx_dev_s g_spi4dev =
{
.spidev = { &g_spi4ops },
.base = PIC32MX_SPI4_K1BASE,
#ifdef CONFIG_PIC32MX_SPI_INTERRUPTS
.vector = PIC32MX_IRQ_SPI4,
.eirq = PIC32MX_IRQSRC_SPI4E,
.rxirq = PIC32MX_IRQSRC_SPI4RX,
.txirq = PIC32MX_IRQSRC_SPI4TX,
#endif
};
#endif
/****************************************************************************
* Public Data
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: spi_getreg
*
* Description:
* Return the contents of one, 32-bit SPI register
*
* Input Parameters:
* priv - A pointer to a PIC32MX SPI state structure
* offset - Offset from the SPI base address to the register of interest
*
* Returned Value:
* The current contents of the register
*
****************************************************************************/
#ifdef CONFIG_PIC32MX_SPI_REGDEBUG
static uint32_t spi_getreg(FAR struct pic32mx_dev_s *priv, unsigned int offset)
{
/* Last address, value, and count */
static uint32_t prevaddr = 0;
static uint32_t prevalue = 0;
static uint32_t count = 0;
/* New address and value */
uint32_t addr;
uint32_t value;
/* Read the value from the register */
addr = priv->base + offset;
value = getreg32(addr);
/* Is this the same value that we read from the same register last time?
* Are we polling the register? If so, suppress some of the output.
*/
if (addr == prevaddr && value == prevalue)
{
if (count == 0xffffffff || ++count > 3)
{
if (count == 4)
{
lldbg("...\n");
}
return value;
}
}
/* No this is a new address or value */
else
{
/* Did we print "..." for the previous value? */
if (count > 3)
{
/* Yes.. then show how many times the value repeated */
lldbg("[repeats %d more times]\n", count-3);
}
/* Save the new address, value, and count */
prevaddr = addr;
prevalue = value;
count = 1;
}
/* Show the register value read */
lldbg("%08x->%08x\n", addr, value);
return value;
}
#else
static uint32_t spi_getreg(FAR struct pic32mx_dev_s *priv, unsigned int offset)
{
return getreg32(priv->base + offset);
}
#endif
/****************************************************************************
* Name: spi_putreg
*
* Description:
* Write a value to one, 32-bit SPI register
*
* Input Parameters:
* priv - A pointer to a PIC32MX SPI state structure
* offset - Offset from the SPI base address to the register of interest
* value - The value to write to the SPI register
*
* Returned Value:
* None
*
****************************************************************************/
#ifdef CONFIG_PIC32MX_SPI_REGDEBUG
static void spi_putreg(FAR struct pic32mx_dev_s *priv, unsigned int offset,
uint32_t value)
{
uint32_t addr;
/* Get the address to write to */
addr = priv->base + offset;
/* Show the register value being written */
lldbg("%08x<-%08x\n", addr, value);
/* Then do the write */
putreg32(value, addr);
}
#else
static void spi_putreg(FAR struct pic32mx_dev_s *priv, unsigned int offset,
uint32_t value)
{
putreg32(value, priv->base + offset);
}
#endif
/****************************************************************************
* Name: spi_lock
*
* Description:
* On SPI busses where there are multiple devices, it will be necessary to
* lock SPI to have exclusive access to the busses for a sequence of
* transfers. The bus should be locked before the chip is selected. After
* locking the SPI bus, the caller should then also call the setfrequency,
* setbits, and setmode methods to make sure that the SPI is properly
* configured for the device. If the SPI buss is being shared, then it
* may have been left in an incompatible state.
*
* Input Parameters:
* dev - Device-specific state data
* lock - true: Lock spi bus, false: unlock SPI bus
*
* Returned Value:
* None
*
****************************************************************************/
static int spi_lock(FAR struct spi_dev_s *dev, bool lock)
{
FAR struct pic32mx_dev_s *priv = (FAR struct pic32mx_dev_s *)dev;
if (lock)
{
/* Take the semaphore (perhaps waiting) */
while (sem_wait(&priv->exclsem) != 0)
{
/* The only case that an error should occur here is if the wait was awakened
* by a signal.
*/
ASSERT(errno == EINTR);
}
}
else
{
(void)sem_post(&priv->exclsem);
}
return OK;
}
/****************************************************************************
* Name: spi_setfrequency
*
* Description:
* Set the SPI frequency.
*
* Input Parameters:
* dev - Device-specific state data
* frequency - The SPI frequency requested
*
* Returned Value:
* Returns the actual frequency selected
*
****************************************************************************/
static uint32_t spi_setfrequency(FAR struct spi_dev_s *dev, uint32_t frequency)
{
FAR struct pic32mx_dev_s *priv = (FAR struct pic32mx_dev_s *)dev;
uint32_t divisor;
uint32_t actual;
uint32_t regval;
spivdbg("Old frequency: %d actual: %d New frequency: %d\n",
priv->frequency, priv->actual, frequency);
/* Check if the requested frequency is the same as the frequency selection */
if (priv->frequency == frequency)
{
/* We are already at this frequency. Return the actual. */
return priv->actual;
}
/* Calculate the divisor
*
* frequency = BOARD_PBCLOCK / (2 * divisor), or
* divisor = (BOARD_PBCLOCK / 2) / frequency
*/
divisor = (BOARD_PBCLOCK / 2) / frequency;
/* The a BRG register value is that divisor minus one
*
* frequency = BOARD_PBCLOCK /(2 * (BRG + 1)), or
* BRG = (BOARD_PBCLOCK / 2) / frequency - 1
*/
regval = divisor;
if (regval > 0)
{
regval--;
}
/* Save the new BRG value */
spi_putreg(priv, PIC32MX_SPI_BRG_OFFSET, regval);
spivdbg("PBCLOCK: %d frequency: %d divisor: %d BRG: %d\n",
BOARD_PBCLOCK, frequency, divisor, regval);
/* Calculate the new actual frequency.
*
* frequency = BOARD_PBCLOCK / (2 * divisor)
*/
actual = (BOARD_PBCLOCK / 2) / divisor;
/* Save the frequency setting */
priv->frequency = frequency;
priv->actual = actual;
spidbg("New frequency: %d Actual: %d\n", frequency, actual);
return actual;
}
/****************************************************************************
* Name: spi_setmode
*
* Description:
* Set the SPI mode. Optional. See enum spi_mode_e for mode definitions
*
* Input Parameters:
* dev - Device-specific state data
* mode - The SPI mode requested
*
* Returned Value:
* none
*
****************************************************************************/
static void spi_setmode(FAR struct spi_dev_s *dev, enum spi_mode_e mode)
{
FAR struct pic32mx_dev_s *priv = (FAR struct pic32mx_dev_s *)dev;
uint32_t regval;
spivdbg("Old mode: %d New mode: %d\n", priv->mode, mode);
/* Has the mode changed? */
if (mode != priv->mode)
{
/* Yes... Set CON register appropriately.
*
* Standard terminology is as follows:
*
* Mode CPOL CPHA
* 0 0 0
* 1 0 1
* 2 1 0
* 3 1 1
*
* CPOL=0: The inactive value of the clock is zero
* CPOL=1: The inactive value of the clock is one
* CPHA=0: Data is captured on the clock's inactive-to-active edge and
* data is propagated on a active-to-inactive edge.
* CPHA=1: Data is captured on the clock's active-to-inactive edge and
* data is propagated on a active-to-inactive edge.
*
* CON Register mapping:
* CPOL=0 corresponds to CON:CKP=0; CPOL=1 corresponds to CON:CKP=1
* CPHA=0 corresponds to CON:CKE=1; CPHA=1 corresponds to CON:CKE=1
*
* In addition, the CON register supports SMP: SPI Data Input Sample
* Phase bit:
*
* 1 = Input data sampled at end of data output time
* 0 = Input data sampled at middle of data output time
*
* Which is hardcoded to 1.
*/
regval = spi_getreg(priv, PIC32MX_SPI_CON_OFFSET);
regval &= ~(SPI_CON_CKP | SPI_CON_CKE);
switch (mode)
{
case SPIDEV_MODE0: /* CPOL=0; CPHA=0 */
break;
case SPIDEV_MODE1: /* CPOL=0; CPHA=1 */
regval |= SPI_CON_CKE;
break;
case SPIDEV_MODE2: /* CPOL=1; CPHA=0 */
regval |= SPI_CON_CKP;
break;
case SPIDEV_MODE3: /* CPOL=1; CPHA=1 */
regval |= (SPI_CON_CKP | SPI_CON_CKE);
break;
default:
DEBUGASSERT(FALSE);
return;
}
spi_putreg(priv, PIC32MX_SPI_CON_OFFSET, regval);
spivdbg("CON: %08x\n", regval);
/* Save the mode so that subsequent re-configuratins will be faster */
priv->mode = mode;
}
}
/****************************************************************************
* Name: spi_setbits
*
* Description:
* Set the number if bits per word.
*
* Input Parameters:
* dev - Device-specific state data
* nbits - The number of bits requests
*
* Returned Value:
* none
*
****************************************************************************/
static void spi_setbits(FAR struct spi_dev_s *dev, int nbits)
{
FAR struct pic32mx_dev_s *priv = (FAR struct pic32mx_dev_s *)dev;
uint32_t setting;
uint32_t regval;
spivdbg("Old nbits: %d New nbits: %d\n", priv->nbits, nbits);
/* Has the number of bits changed? */
DEBUGASSERT(priv && nbits > 7 && nbits < 17);
if (nbits != priv->nbits)
{
/* Yes... Set the CON register appropriately */
if (nbits == 8)
{
setting = SPI_CON_MODE_8BIT;
}
else if (nbits == 16)
{
setting = SPI_CON_MODE_8BIT;
}
else if (nbits == 32)
{
setting = SPI_CON_MODE_8BIT;
}
else
{
spidbg("Unsupported nbits: %d\n", nbits);
return;
}
regval = spi_getreg(priv, PIC32MX_SPI_CON_OFFSET);
regval &= ~SPI_CON_MODE_MASK;
regval |= setting;
regval = spi_getreg(priv, PIC32MX_SPI_CON_OFFSET);
spivdbg("CON: %08x\n", regval);
/* Save the selection so the subsequence re-configurations will be faster */
priv->nbits = nbits;
}
}
/****************************************************************************
* Name: spi_send
*
* Description:
* Exchange one word on SPI
*
* Input Parameters:
* dev - Device-specific state data
* wd - The word to send. the size of the data is determined by the
* number of bits selected for the SPI interface.
*
* Returned Value:
* response
*
****************************************************************************/
static uint16_t spi_send(FAR struct spi_dev_s *dev, uint16_t wd)
{
FAR struct pic32mx_dev_s *priv = (FAR struct pic32mx_dev_s *)dev;
spivdbg("wd: %04x\n", wd);
/* Write the data to transmitted to the SPI Data Register */
spi_putreg(priv, PIC32MX_SPI_BUF_OFFSET, (uint32_t)wd);
#ifdef CONFIG_PIC32MX_SPI_ENHBUF
/* Wait for the SPIRBE bit in the SPI Status Register to be set to 0. In
* enhanced buffer mode, the SPIRBE bit will be cleared in when the
* receive buffer is not empty.
*/
while ((spi_getreg(priv, PIC32MX_SPI_STAT_OFFSET) & SPI_STAT_SPIRBE) != 0);
#else
/* Wait for the SPIRBF bit in the SPI Status Register to be set to 1. In
* normal mode, the SPIRBF bit will be set when receive data is available.
*/
while ((spi_getreg(priv, PIC32MX_SPI_STAT_OFFSET) & SPI_STAT_SPIRBF) == 0);
#endif
/* Return the SPI data */
return (uint16_t)spi_getreg(priv, PIC32MX_SPI_BUF_OFFSET);
}
/****************************************************************************
* Name: spi_sndblock
*
* Description:
* Send a block of data on SPI
*
* Input Parameters:
* dev - Device-specific state data
* buffer - A pointer to the buffer of data to be sent
* nwords - the length of data to send from the buffer in number of words.
* The wordsize is determined by the number of bits-per-word
* selected for the SPI interface. If nbits <= 8, the data is
* packed into uint8_t's; if nbits >8, the data is packed into uint16_t's
*
* Returned Value:
* None
*
****************************************************************************/
static void spi_sndblock(FAR struct spi_dev_s *dev, FAR const void *buffer, size_t nwords)
{
FAR struct pic32mx_dev_s *priv = (FAR struct pic32mx_dev_s *)dev;
FAR uint8_t *ptr = (FAR uint8_t *)buffer;
uint32_t regval;
uint8_t data;
spivdbg("nwords: %d\n", nwords);
while (nwords)
{
/* Write the data to transmitted to the SPI Data Register */
data = *ptr++;
spi_putreg(priv, PIC32MX_SPI_BUF_OFFSET, (uint32_t)data);
#ifdef CONFIG_PIC32MX_SPI_ENHBUF
/* Wait for the SPIRBE bit in the SPI Status Register to be set to 0. In
* enhanced buffer mode, the SPIRBE bit will be cleared in when the
* receive buffer is not empty.
*/
while ((spi_getreg(priv, PIC32MX_SPI_STAT_OFFSET) & SPI_STAT_SPIRBE) != 0);
#else
/* Wait for the SPIRBF bit in the SPI Status Register to be set to 1. In
* normal mode, the SPIRBF bit will be set when receive data is available.
*/
while ((spi_getreg(priv, PIC32MX_SPI_STAT_OFFSET) & SPI_STAT_SPIRBF) == 0);
#endif
/* Read from the buffer register to clear the status bit */
regval = spi_getreg(priv, PIC32MX_SPI_BUF_OFFSET);
UNUSED(regval);
nwords--;
}
}
/****************************************************************************
* Name: spi_recvblock
*
* Description:
* Revice a block of data from SPI
*
* Input Parameters:
* dev - Device-specific state data
* buffer - A pointer to the buffer in which to recieve data
* nwords - the length of data that can be received in the buffer in number
* of words. The wordsize is determined by the number of bits-per-word
* selected for the SPI interface. If nbits <= 8, the data is
* packed into uint8_t's; if nbits >8, the data is packed into uint16_t's
*
* Returned Value:
* None
*
****************************************************************************/
static void spi_recvblock(FAR struct spi_dev_s *dev, FAR void *buffer, size_t nwords)
{
FAR struct pic32mx_dev_s *priv = (FAR struct pic32mx_dev_s *)dev;
FAR uint8_t *ptr = (FAR uint8_t *)buffer;
spivdbg("nwords: %d\n", nwords);
while (nwords)
{
/* Write some dummy data to the SPI Data Register in order to clock the
* read data.
*/
spi_putreg(priv, PIC32MX_SPI_BUF_OFFSET, 0xff);
#ifdef CONFIG_PIC32MX_SPI_ENHBUF
/* Wait for the SPIRBE bit in the SPI Status Register to be set to 0. In
* enhanced buffer mode, the SPIRBE bit will be cleared in when the
* receive buffer is not empty.
*/
while ((spi_getreg(priv, PIC32MX_SPI_STAT_OFFSET) & SPI_STAT_SPIRBE) != 0);
#else
/* Wait for the SPIRBF bit in the SPI Status Register to be set to 1. In
* normal mode, the SPIRBF bit will be set when receive data is available.
*/
while ((spi_getreg(priv, PIC32MX_SPI_STAT_OFFSET) & SPI_STAT_SPIRBF) == 0);
#endif
/* Read the received data from the SPI Data Register */
*ptr++ = (uint8_t)spi_getreg(priv, PIC32MX_SPI_BUF_OFFSET);
nwords--;
}
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: pic32mx_spibus_initialize
*
* Description:
* Initialize the selected SPI port
*
* Input Parameter:
* Port number (for hardware that has mutiple SPI interfaces)
*
* Returned Value:
* Valid SPI device structure reference on succcess; a NULL on failure
*
****************************************************************************/
FAR struct spi_dev_s *pic32mx_spibus_initialize(int port)
{
FAR struct pic32mx_dev_s *priv;
irqstate_t flags;
uint32_t regval;
spivdbg("port: %d\n", port);
/* Select the SPI state structure for this port */
#ifdef CONFIG_PIC32MX_SPI1
if (port == 1)
{
priv = &g_spi1dev;
}
else
#endif
#ifdef CONFIG_PIC32MX_SPI2
if (port == 2)
{
priv = &g_spi2dev;
}
else
#endif
#ifdef CONFIG_PIC32MX_SPI3
if (port == 3)
{
priv = &g_spi3dev;
}
else
#endif
#ifdef CONFIG_PIC32MX_SPI4
if (port == 4)
{
priv = &g_spi4dev;
}
else
#endif
{
spidbg("Unsuppport port: %d\n", port);
return NULL;
}
/* Disable SPI interrupts */
flags = enter_critical_section();
#ifdef CONFIG_PIC32MX_SPI_INTERRUPTS
up_disable_irq(priv->eirq);
up_disable_irq(priv->txirq);
up_disable_irq(priv->rxirq);
#endif
/* Stop and reset the SPI module by clearing the ON bit in the CON register. */
spi_putreg(priv, PIC32MX_SPI_CON_OFFSET, 0);
/* Clear the receive buffer by reading from the BUF register */
regval = spi_getreg(priv, PIC32MX_SPI_BUF_OFFSET);
#ifdef CONFIG_PIC32MX_SPI_INTERRUPTS
/* Attach the interrupt vector. We do this early to make sure that the
* resource is available.
*/
ret = irq_attach(priv->vector, spi_interrupt);
if (ret < 0)
{
spidbg("Failed to attach vector: %d port: %d\n", priv->vector, port);
goto errout;
}
#endif
/* Select a default frequency of approx. 400KHz */
spi_setfrequency((FAR struct spi_dev_s *)priv, 400000);
/* Clear the SPIROV overflow bit (SPIxSTAT:6). */
spi_putreg(priv, PIC32MX_SPI_STATCLR_OFFSET, SPI_STAT_SPIROV);
/* Initial settings 8 bit + master mode + mode 0. NOTE that MSSEN
* not set: The slave select pin must be driven manually via the
* board-specific pic32mx_spiNselect() interface.
*/
regval = (SPI_CON_MSTEN | SPI_CON_SMP | SPI_CON_MODE_8BIT | SPI_CON_ON);
/* Set the ENHBUF bit if using Enhanced Buffer mode. */
#ifdef CONFIG_PIC32MX_SPI_ENHBUF
regval |= (SPI_CON_ENHBUF | SPI_CON_RTXISEL_HALF | SPI_CON_STXISEL_HALF);
#endif
spi_putreg(priv, PIC32MX_SPI_CON_OFFSET, regval);
spivdbg("CON: %08x\n", regval);
/* Set the initial SPI configuration */
priv->nbits = 8;
priv->mode = SPIDEV_MODE0;
/* Initialize the SPI semaphore that enforces mutually exclusive access */
sem_init(&priv->exclsem, 0, 1);
#ifdef CONFIG_PIC32MX_SPI_INTERRUPTS
/* Enable interrupts at the SPI controller */
up_enable_irq(priv->eirq);
up_enable_irq(priv->txirq);
up_enable_irq(priv->rxirq);
#ifdef CONFIG_ARCH_IRQPRIO
/* Set the SPI interrupt priority */
ret = up_prioritize_irq(priv->vector, CONFIG_PIC32MX_SPI_PRIORITY)
if (ret < 0)
{
spidbg("up_prioritize_irq failed: %d\n", ret);
goto errout;
}
#endif
#endif
/* Enable interrupts at the interrupt controller */
leave_critical_section(flags);
return &priv->spidev;
#ifdef CONFIG_PIC32MX_SPI_INTERRUPTS
errout:
leave_critical_section(flags);
return NULL;
#endif
}
#endif /* CONFIG_PIC32MX_SPI */
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