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author | Gregory Nutt <gnutt@nuttx.org> | 2013-07-01 16:50:16 -0600 |
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committer | Gregory Nutt <gnutt@nuttx.org> | 2013-07-01 16:50:16 -0600 |
commit | aeebc7eb724e902efd4bbb6dc34fc57e2a66c9d4 (patch) | |
tree | c3ec8297022067b2071f1fd3fd404a50959eceac /nuttx/drivers/spi | |
parent | 47335ab4bab269c35774964642b823d0367f79ed (diff) | |
download | px4-nuttx-aeebc7eb724e902efd4bbb6dc34fc57e2a66c9d4.tar.gz px4-nuttx-aeebc7eb724e902efd4bbb6dc34fc57e2a66c9d4.tar.bz2 px4-nuttx-aeebc7eb724e902efd4bbb6dc34fc57e2a66c9d4.zip |
Add a general bit-bang SPI lower-half driver and implement the bit-bang driver for the Arduino ITEAD TFT shield
Diffstat (limited to 'nuttx/drivers/spi')
-rw-r--r-- | nuttx/drivers/spi/Make.defs | 52 | ||||
-rwxr-xr-x | nuttx/drivers/spi/spi_bitbang.c | 88 |
2 files changed, 119 insertions, 21 deletions
diff --git a/nuttx/drivers/spi/Make.defs b/nuttx/drivers/spi/Make.defs new file mode 100644 index 000000000..9581a2736 --- /dev/null +++ b/nuttx/drivers/spi/Make.defs @@ -0,0 +1,52 @@ +############################################################################ +# drivers/spi/Make.defs +# +# Copyright (C) 2013 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. +# +############################################################################ + +# Don't build anything if there is no SPI support + +ifeq ($(CONFIG_SPI),y) + +# Include the selected SPI drivers + +ifeq ($(CONFIG_SPI_BITBANG),y) + CSRCS += spi_bitbang.c +endif + +# Include SPI device driver build support + +DEPPATH += --dep-path spi +VPATH += :spi +CFLAGS += ${shell $(INCDIR) $(INCDIROPT) "$(CC)" $(TOPDIR)$(DELIM)drivers$(DELIM)spi} +endif + diff --git a/nuttx/drivers/spi/spi_bitbang.c b/nuttx/drivers/spi/spi_bitbang.c index 27022c375..813292b77 100755 --- a/nuttx/drivers/spi/spi_bitbang.c +++ b/nuttx/drivers/spi/spi_bitbang.c @@ -42,6 +42,7 @@ #include <semaphore.h> #include <assert.h> #include <errno.h> +#include <debug.h> #include <nuttx/spi/spi.h> #include <nuttx/spi/spi_bitbang.h> @@ -123,17 +124,17 @@ static uint16_t spi_send(FAR struct spi_dev_s *dev, uint16_t ch); static void spi_exchange(FAR struct spi_dev_s *dev, FAR const void *txbuffer, FAR void *rxbuffer, size_t nwords); -static uint8_t spi_status(FAR struct spi_dev_s *dev, enum spi_dev_e devid); -#ifdef CONFIG_SPI_CMDDATA -static int spi_cmddata(FAR struct spi_dev_s *dev, enum spi_dev_e devid, - bool cmd); -#endif #ifndef CONFIG_SPI_EXCHANGE 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 +static uint8_t spi_status(FAR struct spi_dev_s *dev, enum spi_dev_e devid); +#ifdef CONFIG_SPI_CMDDATA +static int spi_cmddata(FAR struct spi_dev_s *dev, enum spi_dev_e devid, + bool cmd); +#endif /**************************************************************************** * Private Data @@ -259,22 +260,12 @@ static void spi_select(FAR struct spi_dev_s *dev, enum spi_dev_e devid, static uint32_t spi_setfrequency(FAR struct spi_dev_s *dev, uint32_t frequency) { FAR struct spi_bitbang_s *priv = (FAR struct spi_bitbang_s *)dev; + uint32_t actual; - /* SPI frequency cannot be precisely controlled with a bit-bang interface. - * Freqency corresponds to delay in toggle the SPI clock line: Set high, - * wait, set low, wait, set high, wait, etc. - * - * Here we calcalute the half period of the frequency in nanoseconds (i.e., - * the amount of time that the clock should remain in the high or low state). - * - * frequency = psec / 1 sec - psec = full period in seconds - * psec = 1 sec / frequency - * hpsec = 1 sec / (2 * frequency) - hpsec = half period in seconds - * hpnsec = 1000000000 / (2 * frequency) - hpnsec = half period in nanoseconds - */ - - priv->hpnsec = (1000000000ul + frequency) / (frequency << 2); - return frequency; + DEBUGASSERT(priv && priv->low->setfrequency); + actual = priv->low->setfrequency(priv, frequency); + spivdbg("frequency=%d holdtime=%d actual=%d\n", + frequency, priv->holdtime, actual); } /**************************************************************************** @@ -297,6 +288,7 @@ static void spi_setmode(FAR struct spi_dev_s *dev, enum spi_mode_e mode) FAR struct spi_bitbang_s *priv = (FAR struct spi_bitbang_s *)dev; DEBUGASSERT(priv && priv->low->setmode); priv->low->setmode(priv, mode); + spivdbg("mode=%d exchange=%p\n", mode, priv->exchange); } /**************************************************************************** @@ -327,6 +319,7 @@ static void spi_setbits(FAR struct spi_dev_s *dev, int nbits) DEBUGASSERT(nbits == 8); #endif } + /**************************************************************************** * Name: spi_send * @@ -382,6 +375,7 @@ static void spi_exchange(FAR struct spi_dev_s *dev, uint16_t dataout; uint16_t datain; + spivdbg("txbuffer=%p rxbuffer=%p nwords=%d\n", txbuffer, rxbuffer, nwords); DEBUGASSERT(priv && priv->low && priv->low->exchange); /* If there is no data source, send 0xff */ @@ -497,6 +491,56 @@ static void spi_recvblock(FAR struct spi_dev_s *dev, FAR void *buffer, size_t nw #endif /**************************************************************************** + * Name: spi_status + * + * Description: + * Get status bits associated with the device associated with 'devid' + * + * Input Parameters: + * dev - Device-specific state data + * devid - Identifies the device of interest + * + * Returned Value: + * Bit encoded status byte + * + ****************************************************************************/ + +static uint8_t spi_status(FAR struct spi_dev_s *dev, enum spi_dev_e devid) +{ + FAR struct spi_bitbang_s *priv = (FAR struct spi_bitbang_s *)dev; + DEBUGASSERT(priv && priv->low && priv->low->status); + + return priv->low->status(priv, devid); +} + +/**************************************************************************** + * Name: spi_cmddata + * + * Description: + * Control the SPI CMD/DATA like for the device associated with 'devid' + * + * Input Parameters: + * dev - Device-specific state data + * devid - Identifies the device of interest + * cmd - True:CMD False:DATA + * + * Returned Value: + * OK on success; a negated errno value on failure + * + ****************************************************************************/ + +#ifdef CONFIG_SPI_CMDDATA +static int spi_cmddata(FAR struct spi_dev_s *dev, enum spi_dev_e devid, + bool cmd) +{ + FAR struct spi_bitbang_s *priv = (FAR struct spi_bitbang_s *)dev; + DEBUGASSERTcmddata(priv && priv->low && priv->low->status); + + return priv->low->cmddata(priv, devid, cmd); +} +#endif + +/**************************************************************************** * Public Functions ****************************************************************************/ @@ -531,10 +575,12 @@ FAR struct spi_dev_s *spi_create_bitbang(FAR const struct spi_bitbang_ops_s *low priv->nbits = 8; #endif + sem_init(&priv->exclsem, 0, 1); + /* Select an initial state of mode 0, 8-bits, and 400KHz */ low->setmode(priv, SPIDEV_MODE0); - spi_setfrequency(&priv->dev, 400000); + low->setfrequency(priv, 400000); /* And return the initialized driver structure */ |