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ADS7843E driver is code complete

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git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@4018 42af7a65-404d-4744-a932-0658087f49c3
This commit is contained in:
patacongo 2011-10-04 17:08:59 +00:00
parent 875626b914
commit 3d40cd375f
1 changed files with 188 additions and 22 deletions
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210
arch/arm/src/sam3u/sam3u_spi.c
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@ -120,13 +120,21 @@ struct sam3u_spidev_s
#ifndef CONFIG_SPI_OWNBUS
static int spi_lock(FAR struct spi_dev_s *dev, bool lock);
#endif
static void spi_select(FAR struct spi_dev_s *dev, enum spi_dev_e devid, bool selected);
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_select(FAR struct spi_dev_s *dev, enum spi_dev_e devid,
bool selected);
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);
#ifdef CONFIG_SPI_EXCHANGE
static void spi_exchange(FAR struct spi_dev_s *dev,
FAR const void *txbuffer, FAR void *rxbuffer, size_t nwords);
#else
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);
#endif
/****************************************************************************
* Private Data
@ -148,8 +156,12 @@ static const struct spi_ops_s g_spiops =
.cmddata = sam3u_spicmddata,
#endif
.send = spi_send,
#ifdef CONFIG_SPI_EXCHANGE
.exchange = spi_exchange,
#else
.sndblock = spi_sndblock,
.recvblock = spi_recvblock,
#endif
.registercallback = 0, /* Not implemented */
};
@ -300,7 +312,9 @@ static uint32_t spi_setfrequency(FAR struct spi_dev_s *dev, uint32_t frequency)
{
FAR struct sam3u_spidev_s *priv = (FAR struct sam3u_spidev_s *)dev;
uint32_t actual;
uint32_t divisor;
uint32_t scbr;
uint32_t dlybs;
uint32_t dlybct;
uint32_t regval;
uint32_t regaddr;
@ -317,33 +331,65 @@ static uint32_t spi_setfrequency(FAR struct spi_dev_s *dev, uint32_t frequency)
}
#endif
/* Configure SPI to a frequency as close as possible to the requested frequency. */
/* Configure SPI to a frequency as close as possible to the requested frequency.
*
* SPCK frequency = MCK / SCBR, or SCBR = MCK / frequency
*/
/* frequency = SPI_CLOCK / divisor, or divisor = SPI_CLOCK / frequency */
scbr = SAM3U_MCK_FREQUENCY / frequency;
divisor = SAM3U_MCK_FREQUENCY / frequency;
if (divisor < 8)
if (scbr < 8)
{
divisor = 8;
scbr = 8;
}
else if (divisor > 254)
else if (scbr > 254)
{
divisor = 254;
scbr = 254;
}
divisor = (divisor + 1) & ~1;
scbr = (scbr + 1) & ~1;
/* Save the new divisor value */
/* Save the new scbr value */
regaddr = g_csraddr[priv->cs];
regval = getreg32(regaddr);
regval &= ~SPI_CSR_SCBR_MASK;
putreg32(divisor << SPI_CSR_SCBR_SHIFT, regaddr);
regval &= ~(SPI_CSR_SCBR_MASK|SPI_CSR_DLYBS_MASK|SPI_CSR_DLYBCT_MASK);
regval |= scbr << SPI_CSR_SCBR_SHIFT;
/* Calculate the new actual */
/* DLYBS: Delay Before SPCK. This field defines the delay from NPCS valid to the
* first valid SPCK transition. When DLYBS equals zero, the NPCS valid to SPCK
* transition is 1/2 the SPCK clock period. Otherwise, the following equations
* determine the delay:
*
* Delay Before SPCK = DLYBS / MCK
*
* For a 2uS delay
*
* DLYBS = MCK * 0.000002 = MCK / 500000
*/
actual = SAM3U_MCK_FREQUENCY / divisor;
dlybs = SAM3U_MCK_FREQUENCY / 500000;
regval |= dlybs << SPI_CSR_DLYBS_SHIFT;
/* DLYBCT: Delay Between Consecutive Transfers. This field defines the delay
* between two consecutive transfers with the same peripheral without removing
* the chip select. The delay is always inserted after each transfer and
* before removing the chip select if needed.
*
* Delay Between Consecutive Transfers = (32 x DLYBCT) / MCK
*
* For a 5uS delay:
*
* DLYBCT = MCK * 0.000005 / 32 = MCK / 200000 / 32
*/
dlybct = SAM3U_MCK_FREQUENCY / 200000 / 32;
regval |= dlybct << SPI_CSR_DLYBCT_SHIFT;
putreg32(regval, regaddr);
/* Calculate the new actual frequency */
actual = SAM3U_MCK_FREQUENCY / scbr;
/* Save the frequency setting */
@ -487,6 +533,11 @@ 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 wd)
{
#ifdef CONFIG_SPI_VARSELECT
FAR struct sam3u_spidev_s *priv = (FAR struct sam3u_spidev_s *)dev;
uint32_t tdr = (uint32_t)priv->cs << SPI_TDR_PCS_SHIFT;
#endif
/* Wait for any previous data written to the TDR to be transferred to the
* serializer.
*/
@ -495,7 +546,11 @@ static uint16_t spi_send(FAR struct spi_dev_s *dev, uint16_t wd)
/* Write the data to transmitted to the Transmit Data Register (TDR) */
#ifdef CONFIG_SPI_VARSELECT
putreg32((uint32_t)wd | tdr | SPI_TDR_LASTXFER, SAM3U_SPI_TDR);
#else
putreg32((uint32_t)wd, SAM3U_SPI_TDR);
#endif
/* Wait for the read data to be available in the RDR */
@ -506,7 +561,91 @@ static uint16_t spi_send(FAR struct spi_dev_s *dev, uint16_t wd)
return (uint16_t)getreg32(SAM3U_SPI_RDR);
}
/*************************************************************************
/****************************************************************************
* Name: spi_exchange
*
* Description:
* Exahange a block of data from SPI. Required.
*
* Input Parameters:
* dev - Device-specific state data
* txbuffer - A pointer to the buffer of data to be sent
* rxbuffer - A pointer to the buffer in which to recieve data
* nwords - the length of data that to be exchanged in units 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
*
****************************************************************************/
#ifdef CONFIG_SPI_EXCHANGE
static void spi_exchange(FAR struct spi_dev_s *dev,
FAR const void *txbuffer, FAR void *rxbuffer,
size_t nwords)
{
#ifdef CONFIG_SPI_VARSELECT
FAR struct sam3u_spidev_s *priv = (FAR struct sam3u_spidev_s *)dev;
uint32_t tdr = (uint32_t)priv->cs << SPI_TDR_PCS_SHIFT;
#endif
FAR uint8_t *rxptr = (FAR uint8_t*)rxbuffer;
FAR uint8_t *txptr = (FAR uint8_t*)txbuffer;
uint8_t data;
spidbg("nwords: %d\n", nwords);
/* Loop, sending each word in the user-provied data buffer */
for ( ; nwords > 0; nwords--)
{
/* Wait for any previous data written to the TDR to be transferred
* to the serializer.
*/
while ((getreg32(SAM3U_SPI_SR) & SPI_INT_TDRE) == 0);
/* Get the data to send (0xff if there is no data source) */
if (rxptr)
{
data = *txptr++;
}
else
{
data = 0xff;
}
/* Write the data to transmitted to the Transmit Data Register (TDR) */
#ifdef CONFIG_SPI_VARSELECT
if (nwords == 1)
{
tdr |= SPI_TDR_LASTXFER;
}
putreg32((uint32_t)data | tdr, SAM3U_SPI_TDR);
#else
putreg32((uint32_t)data, SAM3U_SPI_TDR);
#endif
/* Wait for the read data to be available in the RDR */
while ((getreg32(SAM3U_SPI_SR) & SPI_INT_RDRF) == 0);
/* Read the received data from the SPI Data Register */
data = (uint8_t)getreg32(SAM3U_SPI_RDR);
if (rxptr)
{
*txptr++ = data;
}
}
}
#endif
/***************************************************************************
* Name: spi_sndblock
*
* Description:
@ -525,8 +664,13 @@ static uint16_t spi_send(FAR struct spi_dev_s *dev, uint16_t wd)
*
****************************************************************************/
#ifndef CONFIG_SPI_EXCHANGE
static void spi_sndblock(FAR struct spi_dev_s *dev, FAR const void *buffer, size_t nwords)
{
#ifdef CONFIG_SPI_VARSELECT
FAR struct sam3u_spidev_s *priv = (FAR struct sam3u_spidev_s *)dev;
uint32_t tdr = (uint32_t)priv->cs << SPI_TDR_PCS_SHIFT;
#endif
FAR uint8_t *ptr = (FAR uint8_t*)buffer;
uint8_t data;
@ -545,9 +689,18 @@ static void spi_sndblock(FAR struct spi_dev_s *dev, FAR const void *buffer, size
/* Write the data to transmitted to the Transmit Data Register (TDR) */
data = *ptr++;
#ifdef CONFIG_SPI_VARSELECT
if (nwords == 1)
{
tdr |= SPI_TDR_LASTXFER;
}
putreg32((uint32_t)data | tdr, SAM3U_SPI_TDR);
#else
putreg32((uint32_t)data, SAM3U_SPI_TDR);
#endif
}
}
#endif
/****************************************************************************
* Name: spi_recvblock
@ -568,8 +721,13 @@ static void spi_sndblock(FAR struct spi_dev_s *dev, FAR const void *buffer, size
*
****************************************************************************/
#ifndef CONFIG_SPI_EXCHANGE
static void spi_recvblock(FAR struct spi_dev_s *dev, FAR void *buffer, size_t nwords)
{
#ifdef CONFIG_SPI_VARSELECT
FAR struct sam3u_spidev_s *priv = (FAR struct sam3u_spidev_s *)dev;
uint32_t tdr = (uint32_t)priv->cs << SPI_TDR_PCS_SHIFT;
#endif
FAR uint8_t *ptr = (FAR uint8_t*)buffer;
spidbg("nwords: %d\n", nwords);
@ -588,8 +746,15 @@ static void spi_recvblock(FAR struct spi_dev_s *dev, FAR void *buffer, size_t nw
* to clock the read data.
*/
#ifdef CONFIG_SPI_VARSELECT
if (nwords == 1)
{
tdr |= SPI_TDR_LASTXFER;
}
putreg32(0xff | tdr, SAM3U_SPI_TDR);
#else
putreg32(0xff, SAM3U_SPI_TDR);
#endif
/* Wait for the read data to be available in the RDR */
while ((getreg32(SAM3U_SPI_SR) & SPI_INT_RDRF) == 0);
@ -599,6 +764,7 @@ static void spi_recvblock(FAR struct spi_dev_s *dev, FAR void *buffer, size_t nw
*ptr++ = (uint8_t)getreg32(SAM3U_SPI_RDR);
}
}
#endif
/****************************************************************************
* Public Functions
@ -657,8 +823,8 @@ FAR struct spi_dev_s *up_spiinitialize(int port)
irqrestore(flags);
/* Configure the SPI mode register */
#warning "Need to review this -- what other settngs are necessary"
putreg32(SPI_MR_MSTR, SAM3U_SPI_MR);
putreg32(SPI_MR_MSTR | SPI_MR_MODFDIS, SAM3U_SPI_MR);
/* And enable the SPI */