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author | patacongo <patacongo@42af7a65-404d-4744-a932-0658087f49c3> | 2012-07-04 23:19:59 +0000 |
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committer | patacongo <patacongo@42af7a65-404d-4744-a932-0658087f49c3> | 2012-07-04 23:19:59 +0000 |
commit | d2a5c3d4f5b9899dc5de05c49ede4e616fae9a64 (patch) | |
tree | 0069f942928564b5216301ec2623b1f102d46fb5 /nuttx/arch/arm/src/lpc43xx/lpc43_spi.c | |
parent | 08088bc230efd32182b46b42b42e2b5e7d83a265 (diff) | |
download | px4-nuttx-d2a5c3d4f5b9899dc5de05c49ede4e616fae9a64.tar.gz px4-nuttx-d2a5c3d4f5b9899dc5de05c49ede4e616fae9a64.tar.bz2 px4-nuttx-d2a5c3d4f5b9899dc5de05c49ede4e616fae9a64.zip |
STM32 PM update
git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@4908 42af7a65-404d-4744-a932-0658087f49c3
Diffstat (limited to 'nuttx/arch/arm/src/lpc43xx/lpc43_spi.c')
-rw-r--r-- | nuttx/arch/arm/src/lpc43xx/lpc43_spi.c | 604 |
1 files changed, 604 insertions, 0 deletions
diff --git a/nuttx/arch/arm/src/lpc43xx/lpc43_spi.c b/nuttx/arch/arm/src/lpc43xx/lpc43_spi.c new file mode 100644 index 000000000..52910a4a1 --- /dev/null +++ b/nuttx/arch/arm/src/lpc43xx/lpc43_spi.c @@ -0,0 +1,604 @@ +/**************************************************************************** + * arch/arm/src/lpc43xx/lpc43_spi.c + * + * Copyright (C) 2012 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/arch.h> +#include <nuttx/spi.h> + +#include "up_internal.h" +#include "up_arch.h" + +#include "chip.h" +#include "lpc43_syscon.h" +#include "lpc43_pinconn.h" +#include "lpc43_spi.h" + +#ifdef CONFIG_LPC43_SPI + +/**************************************************************************** + * Definitions + ****************************************************************************/ + +/* Enables debug output from this file (needs CONFIG_DEBUG too) */ + +#ifdef CONFIG_DEBUG_SPI +# define spidbg lldbg +# ifdef CONFIG_DEBUG_VERBOSE +# define spivdbg lldbg +# else +# define spivdbg(x...) +# endif +#else +# undef CONFIG_DEBUG_VERBOSE +# define spidbg(x...) +# define spivdbg(x...) +#endif + +/* SPI Clocking. + * + * The CPU clock by 1, 2, 4, or 8 to get the SPI peripheral clock (SPI_CLOCK). + * SPI_CLOCK may be further divided by 8-254 to get the SPI clock. If we + * want a usable range of 4KHz to 25MHz for the SPI, then: + * + * 1. SPICLK must be greater than (8*25MHz) = 200MHz (so we can't reach 25MHz), + * and + * 2. SPICLK must be less than (254*40Khz) = 101.6MHz. + * + * If we assume that CCLK less than or equal to 100MHz, we can just + * use the CCLK undivided to get the SPI_CLOCK. + */ + +#define SPI_PCLKSET_DIV SYSCON_PCLKSEL_CCLK +#define SPI_CLOCK LPC43_CCLK + +/**************************************************************************** + * Private Types + ****************************************************************************/ + +/* This structure descibes the state of the SSP driver */ + +struct lpc43_spidev_s +{ + struct spi_dev_s spidev; /* Externally visible part of the SPI interface */ +#ifndef CONFIG_SPI_OWNBUS + 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 */ +#endif +}; + +/**************************************************************************** + * Private Function Prototypes + ****************************************************************************/ + +/* SPI methods */ + +#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_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 + ****************************************************************************/ + +static const struct spi_ops_s g_spiops = +{ +#ifndef CONFIG_SPI_OWNBUS + .lock = spi_lock, +#endif + .select = lpc43_spiselect, + .setfrequency = spi_setfrequency, + .setmode = spi_setmode, + .setbits = spi_setbits, + .status = lpc43_spistatus, +#ifdef CONFIG_SPI_CMDDATA + .cmddata = lpc43_spicmddata, +#endif + .send = spi_send, + .sndblock = spi_sndblock, + .recvblock = spi_recvblock, +#ifdef CONFIG_SPI_CALLBACK + .registercallback = lpc43_spiregister, /* Provided externally */ +#else + .registercallback = 0, /* Not implemented */ +#endif +}; + +static struct lpc43_spidev_s g_spidev = +{ + .spidev = { &g_spiops }, +}; + +/**************************************************************************** + * Public Data + ****************************************************************************/ + +/**************************************************************************** + * Private Functions + ****************************************************************************/ + +/**************************************************************************** + * 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 + * + ****************************************************************************/ + +#ifndef CONFIG_SPI_OWNBUS +static int spi_lock(FAR struct spi_dev_s *dev, bool lock) +{ + FAR struct lpc43_spidev_s *priv = (FAR struct lpc43_spidev_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; +} +#endif + +/**************************************************************************** + * 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 lpc43_spidev_s *priv = (FAR struct lpc43_spidev_s *)dev; + uint32_t divisor; + uint32_t actual; + + /* Check if the requested frequence is the same as the frequency selection */ + + DEBUGASSERT(priv && frequency <= SPI_CLOCK / 2); +#ifndef CONFIG_SPI_OWNBUS + if (priv->frequency == frequency) + { + /* We are already at this frequency. Return the actual. */ + + return priv->actual; + } +#endif + + /* frequency = SPI_CLOCK / divisor, or divisor = SPI_CLOCK / frequency */ + + divisor = SPI_CLOCK / frequency; + + /* The SPI CCR register must contain an even number greater than or equal to 8. */ + + if (divisor < 8) + { + divisor = 8; + } + else if (divisor > 254) + { + divisor = 254; + } + + divisor = (divisor + 1) & ~1; + + /* Save the new divisor value */ + + putreg32(divisor, LPC43_SPI_CCR); + + /* Calculate the new actual */ + + actual = SPI_CLOCK / divisor; + + /* Save the frequency setting */ + +#ifndef CONFIG_SPI_OWNBUS + priv->frequency = frequency; + priv->actual = actual; +#endif + + spidbg("Frequency %d->%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 lpc43_spidev_s *priv = (FAR struct lpc43_spidev_s *)dev; + uint32_t regval; + + /* Has the mode changed? */ + +#ifndef CONFIG_SPI_OWNBUS + if (mode != priv->mode) + { +#endif + /* Yes... Set CR appropriately */ + + regval = getreg32(LPC43_SPI_CR); + regval &= ~(SPI_CR_CPOL|SPI_CR_CPHA); + + switch (mode) + { + case SPIDEV_MODE0: /* CPOL=0; CPHA=0 */ + break; + + case SPIDEV_MODE1: /* CPOL=0; CPHA=1 */ + regval |= SPI_CR_CPHA; + break; + + case SPIDEV_MODE2: /* CPOL=1; CPHA=0 */ + regval |= SPI_CR_CPOL; + break; + + case SPIDEV_MODE3: /* CPOL=1; CPHA=1 */ + regval |= (SPI_CR_CPOL|SPI_CR_CPHA); + break; + + default: + DEBUGASSERT(FALSE); + return; + } + + putreg32(regval, LPC43_SPI_CR); + + /* Save the mode so that subsequent re-configuratins will be faster */ + +#ifndef CONFIG_SPI_OWNBUS + priv->mode = mode; + } +#endif +} + +/**************************************************************************** + * 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 lpc43_spidev_s *priv = (FAR struct lpc43_spidev_s *)dev; + uint32_t regval; + + /* Has the number of bits changed? */ + + DEBUGASSERT(priv && nbits > 7 && nbits < 17); +#ifndef CONFIG_SPI_OWNBUS + if (nbits != priv->nbits) + { +#endif + /* Yes... Set CR appropriately */ + + regval = getreg32(LPC43_SPI_CR); + regval &= ~SPI_CR_BITS_MASK; + regval |= (nbits << SPI_CR_BITS_SHIFT) & SPI_CR_BITS_MASK; + regval |= SPI_CR_BITENABLE; + regval = getreg32(LPC43_SPI_CR); + + /* Save the selection so the subsequence re-configurations will be faster */ + +#ifndef CONFIG_SPI_OWNBUS + priv->nbits = nbits; + } +#endif +} + +/**************************************************************************** + * 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) +{ + /* Write the data to transmitted to the SPI Data Register */ + + putreg32((uint32_t)wd, LPC43_SPI_DR); + + /* Wait for the SPIF bit in the SPI Status Register to be set to 1. The + * SPIF bit will be set after the last sampling clock edge of the SPI + * data transfer. + */ + + while ((getreg32(LPC43_SPI_SR) & SPI_SR_SPIF) == 0); + + /* Read the SPI Status Register again to clear the status bit */ + + (void)getreg32(LPC43_SPI_SR); + return (uint16_t)getreg32(LPC43_SPI_DR); +} + +/************************************************************************* + * 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 uint8_t *ptr = (FAR uint8_t*)buffer; + uint8_t data; + + spidbg("nwords: %d\n", nwords); + while (nwords) + { + /* Write the data to transmitted to the SPI Data Register */ + + data = *ptr++; + putreg32((uint32_t)data, LPC43_SPI_DR); + + /* Wait for the SPIF bit in the SPI Status Register to be set to 1. The + * SPIF bit will be set after the last sampling clock edge of the SPI + * data transfer. + */ + + while ((getreg32(LPC43_SPI_SR) & SPI_SR_SPIF) == 0); + + /* Read the SPI Status Register again to clear the status bit */ + + (void)getreg32(LPC43_SPI_SR); + 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 uint8_t *ptr = (FAR uint8_t*)buffer; + + spidbg("nwords: %d\n", nwords); + while (nwords) + { + /* Write some dummy data to the SPI Data Register in order to clock the + * read data. + */ + + putreg32(0xff, LPC43_SPI_DR); + + /* Wait for the SPIF bit in the SPI Status Register to be set to 1. The + * SPIF bit will be set after the last sampling clock edge of the SPI + * data transfer. + */ + + while ((getreg32(LPC43_SPI_SR) & SPI_SR_SPIF) == 0); + + /* Read the SPI Status Register again to clear the status bit */ + + (void)getreg32(LPC43_SPI_SR); + + /* Read the received data from the SPI Data Register */ + + *ptr++ = (uint8_t)getreg32(LPC43_SPI_DR); + nwords--; + } +} + +/**************************************************************************** + * Public Functions + ****************************************************************************/ + +/**************************************************************************** + * Name: lpc43_spiinitialize + * + * Description: + * Initialize the SPI port + * + * Input Parameter: + * port Port number (must be zero) + * + * Returned Value: + * Valid SPI device structure reference on succcess; a NULL on failure + * + ****************************************************************************/ + +FAR struct spi_dev_s *lpc43_spiinitialize(int port) +{ + FAR struct lpc43_spidev_s *priv = &g_spidev; + irqstate_t flags; + uint32_t regval; + + /* Configure multiplexed pins as connected on the board. Chip select + * pins must be configured by board-specific logic. All SPI pins and + * one SPI1 pin (SCK) have multiple, alternative pin selection. + * Definitions in the board.h file must be provided to resolve the + * board-specific pin configuration like: + * + * #define GPIO_SPI_SCK GPIO_SPI_SCK_1 + */ + + flags = irqsave(); + lpc43_configgpio(GPIO_SPI_SCK); + lpc43_configgpio(GPIO_SPI_MISO); + lpc43_configgpio(GPIO_SPI_MOSI); + + /* Configure clocking */ + + regval = getreg32(LPC43_SYSCON_PCLKSEL0); + regval &= ~SYSCON_PCLKSEL0_SPI_MASK; + regval |= (SPI_PCLKSET_DIV << SYSCON_PCLKSEL0_SPI_SHIFT); + putreg32(regval, LPC43_SYSCON_PCLKSEL0); + + /* Enable peripheral clocking to SPI and SPI1 */ + + regval = getreg32(LPC43_SYSCON_PCONP); + regval |= SYSCON_PCONP_PCSPI; + putreg32(regval, LPC43_SYSCON_PCONP); + irqrestore(flags); + + /* Configure 8-bit SPI mode and master mode */ + + putreg32(SPI_CR_BITS_8BITS|SPI_CR_BITENABLE|SPI_CR_MSTR, LPC43_SPI_CR); + + /* Set the initial SPI configuration */ + +#ifndef CONFIG_SPI_OWNBUS + priv->frequency = 0; + priv->nbits = 8; + priv->mode = SPIDEV_MODE0; +#endif + + /* Select a default frequency of approx. 400KHz */ + + spi_setfrequency((FAR struct spi_dev_s *)priv, 400000); + + /* Initialize the SPI semaphore that enforces mutually exclusive access */ + +#ifndef CONFIG_SPI_OWNBUS + sem_init(&priv->exclsem, 0, 1); +#endif + return &priv->spidev; +} + +#endif /* CONFIG_LPC43_SPI */ + |