ADS7843E driver is code complete
git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@4018 42af7a65-404d-4744-a932-0658087f49c3
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@ -120,13 +120,21 @@ struct sam3u_spidev_s
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#ifndef CONFIG_SPI_OWNBUS
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static int spi_lock(FAR struct spi_dev_s *dev, bool lock);
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#endif
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static void spi_select(FAR struct spi_dev_s *dev, enum spi_dev_e devid, bool selected);
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static uint32_t spi_setfrequency(FAR struct spi_dev_s *dev, uint32_t frequency);
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static void spi_setmode(FAR struct spi_dev_s *dev, enum spi_mode_e mode);
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static void spi_select(FAR struct spi_dev_s *dev, enum spi_dev_e devid,
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bool selected);
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static uint32_t spi_setfrequency(FAR struct spi_dev_s *dev,
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uint32_t frequency);
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static void spi_setmode(FAR struct spi_dev_s *dev,
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enum spi_mode_e mode);
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static void spi_setbits(FAR struct spi_dev_s *dev, int nbits);
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static uint16_t spi_send(FAR struct spi_dev_s *dev, uint16_t ch);
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#ifdef CONFIG_SPI_EXCHANGE
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static void spi_exchange(FAR struct spi_dev_s *dev,
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FAR const void *txbuffer, FAR void *rxbuffer, size_t nwords);
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#else
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static void spi_sndblock(FAR struct spi_dev_s *dev, FAR const void *buffer, size_t nwords);
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static void spi_recvblock(FAR struct spi_dev_s *dev, FAR void *buffer, size_t nwords);
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#endif
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/****************************************************************************
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* Private Data
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@ -148,8 +156,12 @@ static const struct spi_ops_s g_spiops =
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.cmddata = sam3u_spicmddata,
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#endif
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.send = spi_send,
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#ifdef CONFIG_SPI_EXCHANGE
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.exchange = spi_exchange,
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#else
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.sndblock = spi_sndblock,
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.recvblock = spi_recvblock,
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#endif
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.registercallback = 0, /* Not implemented */
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};
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@ -300,7 +312,9 @@ static uint32_t spi_setfrequency(FAR struct spi_dev_s *dev, uint32_t frequency)
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{
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FAR struct sam3u_spidev_s *priv = (FAR struct sam3u_spidev_s *)dev;
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uint32_t actual;
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uint32_t divisor;
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uint32_t scbr;
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uint32_t dlybs;
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uint32_t dlybct;
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uint32_t regval;
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uint32_t regaddr;
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@ -317,33 +331,65 @@ static uint32_t spi_setfrequency(FAR struct spi_dev_s *dev, uint32_t frequency)
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}
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#endif
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/* Configure SPI to a frequency as close as possible to the requested frequency. */
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/* Configure SPI to a frequency as close as possible to the requested frequency.
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*
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* SPCK frequency = MCK / SCBR, or SCBR = MCK / frequency
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*/
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/* frequency = SPI_CLOCK / divisor, or divisor = SPI_CLOCK / frequency */
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scbr = SAM3U_MCK_FREQUENCY / frequency;
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divisor = SAM3U_MCK_FREQUENCY / frequency;
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if (divisor < 8)
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if (scbr < 8)
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{
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divisor = 8;
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scbr = 8;
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}
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else if (divisor > 254)
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else if (scbr > 254)
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{
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divisor = 254;
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scbr = 254;
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}
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divisor = (divisor + 1) & ~1;
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scbr = (scbr + 1) & ~1;
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/* Save the new divisor value */
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/* Save the new scbr value */
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regaddr = g_csraddr[priv->cs];
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regval = getreg32(regaddr);
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regval &= ~SPI_CSR_SCBR_MASK;
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putreg32(divisor << SPI_CSR_SCBR_SHIFT, regaddr);
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regval &= ~(SPI_CSR_SCBR_MASK|SPI_CSR_DLYBS_MASK|SPI_CSR_DLYBCT_MASK);
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regval |= scbr << SPI_CSR_SCBR_SHIFT;
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/* Calculate the new actual */
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/* DLYBS: Delay Before SPCK. This field defines the delay from NPCS valid to the
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* first valid SPCK transition. When DLYBS equals zero, the NPCS valid to SPCK
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* transition is 1/2 the SPCK clock period. Otherwise, the following equations
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* determine the delay:
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*
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* Delay Before SPCK = DLYBS / MCK
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*
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* For a 2uS delay
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*
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* DLYBS = MCK * 0.000002 = MCK / 500000
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*/
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actual = SAM3U_MCK_FREQUENCY / divisor;
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dlybs = SAM3U_MCK_FREQUENCY / 500000;
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regval |= dlybs << SPI_CSR_DLYBS_SHIFT;
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/* DLYBCT: Delay Between Consecutive Transfers. This field defines the delay
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* between two consecutive transfers with the same peripheral without removing
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* the chip select. The delay is always inserted after each transfer and
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* before removing the chip select if needed.
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*
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* Delay Between Consecutive Transfers = (32 x DLYBCT) / MCK
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*
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* For a 5uS delay:
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*
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* DLYBCT = MCK * 0.000005 / 32 = MCK / 200000 / 32
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*/
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dlybct = SAM3U_MCK_FREQUENCY / 200000 / 32;
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regval |= dlybct << SPI_CSR_DLYBCT_SHIFT;
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putreg32(regval, regaddr);
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/* Calculate the new actual frequency */
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actual = SAM3U_MCK_FREQUENCY / scbr;
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/* Save the frequency setting */
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@ -487,6 +533,11 @@ static void spi_setbits(FAR struct spi_dev_s *dev, int nbits)
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static uint16_t spi_send(FAR struct spi_dev_s *dev, uint16_t wd)
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{
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#ifdef CONFIG_SPI_VARSELECT
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FAR struct sam3u_spidev_s *priv = (FAR struct sam3u_spidev_s *)dev;
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uint32_t tdr = (uint32_t)priv->cs << SPI_TDR_PCS_SHIFT;
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#endif
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/* Wait for any previous data written to the TDR to be transferred to the
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* serializer.
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*/
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@ -495,7 +546,11 @@ static uint16_t spi_send(FAR struct spi_dev_s *dev, uint16_t wd)
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/* Write the data to transmitted to the Transmit Data Register (TDR) */
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#ifdef CONFIG_SPI_VARSELECT
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putreg32((uint32_t)wd | tdr | SPI_TDR_LASTXFER, SAM3U_SPI_TDR);
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#else
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putreg32((uint32_t)wd, SAM3U_SPI_TDR);
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#endif
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/* Wait for the read data to be available in the RDR */
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@ -506,7 +561,91 @@ static uint16_t spi_send(FAR struct spi_dev_s *dev, uint16_t wd)
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return (uint16_t)getreg32(SAM3U_SPI_RDR);
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}
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/*************************************************************************
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/****************************************************************************
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* Name: spi_exchange
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*
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* Description:
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* Exahange a block of data from SPI. Required.
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*
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* Input Parameters:
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* dev - Device-specific state data
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* txbuffer - A pointer to the buffer of data to be sent
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* rxbuffer - A pointer to the buffer in which to recieve data
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* nwords - the length of data that to be exchanged in units of words.
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* The wordsize is determined by the number of bits-per-word
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* selected for the SPI interface. If nbits <= 8, the data is
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* packed into uint8_t's; if nbits >8, the data is packed into
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* uint16_t's
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*
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* Returned Value:
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* None
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*
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****************************************************************************/
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#ifdef CONFIG_SPI_EXCHANGE
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static void spi_exchange(FAR struct spi_dev_s *dev,
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FAR const void *txbuffer, FAR void *rxbuffer,
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size_t nwords)
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{
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#ifdef CONFIG_SPI_VARSELECT
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FAR struct sam3u_spidev_s *priv = (FAR struct sam3u_spidev_s *)dev;
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uint32_t tdr = (uint32_t)priv->cs << SPI_TDR_PCS_SHIFT;
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#endif
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FAR uint8_t *rxptr = (FAR uint8_t*)rxbuffer;
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FAR uint8_t *txptr = (FAR uint8_t*)txbuffer;
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uint8_t data;
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spidbg("nwords: %d\n", nwords);
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/* Loop, sending each word in the user-provied data buffer */
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for ( ; nwords > 0; nwords--)
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{
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/* Wait for any previous data written to the TDR to be transferred
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* to the serializer.
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*/
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while ((getreg32(SAM3U_SPI_SR) & SPI_INT_TDRE) == 0);
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/* Get the data to send (0xff if there is no data source) */
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if (rxptr)
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{
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data = *txptr++;
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}
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else
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{
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data = 0xff;
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}
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/* Write the data to transmitted to the Transmit Data Register (TDR) */
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#ifdef CONFIG_SPI_VARSELECT
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if (nwords == 1)
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{
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tdr |= SPI_TDR_LASTXFER;
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}
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putreg32((uint32_t)data | tdr, SAM3U_SPI_TDR);
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#else
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putreg32((uint32_t)data, SAM3U_SPI_TDR);
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#endif
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/* Wait for the read data to be available in the RDR */
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while ((getreg32(SAM3U_SPI_SR) & SPI_INT_RDRF) == 0);
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/* Read the received data from the SPI Data Register */
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data = (uint8_t)getreg32(SAM3U_SPI_RDR);
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if (rxptr)
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{
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*txptr++ = data;
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}
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}
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}
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#endif
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/***************************************************************************
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* Name: spi_sndblock
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*
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* Description:
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@ -525,8 +664,13 @@ static uint16_t spi_send(FAR struct spi_dev_s *dev, uint16_t wd)
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*
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****************************************************************************/
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#ifndef CONFIG_SPI_EXCHANGE
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static void spi_sndblock(FAR struct spi_dev_s *dev, FAR const void *buffer, size_t nwords)
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{
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#ifdef CONFIG_SPI_VARSELECT
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FAR struct sam3u_spidev_s *priv = (FAR struct sam3u_spidev_s *)dev;
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uint32_t tdr = (uint32_t)priv->cs << SPI_TDR_PCS_SHIFT;
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#endif
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FAR uint8_t *ptr = (FAR uint8_t*)buffer;
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uint8_t data;
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@ -545,9 +689,18 @@ static void spi_sndblock(FAR struct spi_dev_s *dev, FAR const void *buffer, size
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/* Write the data to transmitted to the Transmit Data Register (TDR) */
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data = *ptr++;
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#ifdef CONFIG_SPI_VARSELECT
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if (nwords == 1)
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{
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tdr |= SPI_TDR_LASTXFER;
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}
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putreg32((uint32_t)data | tdr, SAM3U_SPI_TDR);
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#else
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putreg32((uint32_t)data, SAM3U_SPI_TDR);
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#endif
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}
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}
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#endif
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/****************************************************************************
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* Name: spi_recvblock
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@ -568,8 +721,13 @@ static void spi_sndblock(FAR struct spi_dev_s *dev, FAR const void *buffer, size
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*
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****************************************************************************/
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#ifndef CONFIG_SPI_EXCHANGE
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static void spi_recvblock(FAR struct spi_dev_s *dev, FAR void *buffer, size_t nwords)
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{
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#ifdef CONFIG_SPI_VARSELECT
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FAR struct sam3u_spidev_s *priv = (FAR struct sam3u_spidev_s *)dev;
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uint32_t tdr = (uint32_t)priv->cs << SPI_TDR_PCS_SHIFT;
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#endif
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FAR uint8_t *ptr = (FAR uint8_t*)buffer;
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spidbg("nwords: %d\n", nwords);
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@ -588,8 +746,15 @@ static void spi_recvblock(FAR struct spi_dev_s *dev, FAR void *buffer, size_t nw
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* to clock the read data.
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*/
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#ifdef CONFIG_SPI_VARSELECT
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if (nwords == 1)
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{
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tdr |= SPI_TDR_LASTXFER;
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}
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putreg32(0xff | tdr, SAM3U_SPI_TDR);
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#else
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putreg32(0xff, SAM3U_SPI_TDR);
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#endif
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/* Wait for the read data to be available in the RDR */
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while ((getreg32(SAM3U_SPI_SR) & SPI_INT_RDRF) == 0);
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@ -599,6 +764,7 @@ static void spi_recvblock(FAR struct spi_dev_s *dev, FAR void *buffer, size_t nw
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*ptr++ = (uint8_t)getreg32(SAM3U_SPI_RDR);
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}
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}
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#endif
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/****************************************************************************
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* Public Functions
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@ -657,8 +823,8 @@ FAR struct spi_dev_s *up_spiinitialize(int port)
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irqrestore(flags);
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/* Configure the SPI mode register */
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#warning "Need to review this -- what other settngs are necessary"
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putreg32(SPI_MR_MSTR, SAM3U_SPI_MR);
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putreg32(SPI_MR_MSTR | SPI_MR_MODFDIS, SAM3U_SPI_MR);
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/* And enable the SPI */
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