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nuttx/arch/arm/src/kl/kl_spi.c

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/****************************************************************************
* arch/arm/src/kl/kl_spi.c
*
* 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.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <stdint.h>
#include <semaphore.h>
#include <errno.h>
#include <assert.h>
#include <debug.h>
#include <nuttx/spi/spi.h>
#include <arch/irq.h>
#include <arch/board/board.h>
#include "up_arch.h"
#include "kl_spi.h"
#include "kl_gpio.h"
#include "chip/kl_memorymap.h"
#include "chip/kl_sim.h"
#include "chip/kl_spi.h"
#include "chip/kl_pinmux.h"
#if defined(CONFIG_KL_SPI0) || defined(CONFIG_KL_SPI1)
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* Debug ********************************************************************/
/* The following enable debug output from this file:
*
* CONFIG_DEBUG - Define to enable general debug features
* CONFIG_DEBUG_SPI - Define to enable basic SSP debug (needs CONFIG_DEBUG)
* CONFIG_DEBUG_VERBOSE - Define to enable verbose SSP debug
*/
#ifdef CONFIG_DEBUG_SPI
# define spidbg lldbg
# ifdef CONFIG_DEBUG_VERBOSE
# define spivdbg lldbg
# else
# define spivdbg(x...)
# endif
#else
# define spidbg(x...)
# define spivdbg(x...)
#endif
/****************************************************************************
* Private Types
****************************************************************************/
struct kl_spidev_s
{
struct spi_dev_s spidev; /* Externally visible part of the SPI interface */
uint32_t spibase; /* Base address of SPI registers */
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
************************************************************************************/
/* Helpers */
static inline uint8_t spi_getreg(FAR struct kl_spidev_s *priv, uint8_t offset);
static inline void spi_putreg(FAR struct kl_spidev_s *priv, uint8_t offset,
uint8_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 wd);
static void spi_exchange(FAR struct spi_dev_s *dev, FAR const void *txbuffer,
FAR void *rxbuffer, size_t nwords);
#ifndef CONFIG_SPI_EXCHANGE
static void spi_sndblock(FAR struct spi_dev_s *dev, FAR const void *txbuffer,
size_t nwords);
static void spi_recvblock(FAR struct spi_dev_s *dev, FAR void *rxbuffer,
size_t nwords);
#endif
/************************************************************************************
* Private Data
************************************************************************************/
#ifdef CONFIG_KL_SPI0
static const struct spi_ops_s g_spi0ops =
{
.lock = spi_lock,
.select = kl_spi0select,
.setfrequency = spi_setfrequency,
.setmode = spi_setmode,
.setbits = spi_setbits,
#ifdef CONFIG_SPI_HWFEATURES
.hwfeatures = 0, /* Not supported */
#endif
.status = kl_spi0status,
#ifdef CONFIG_SPI_CMDDATA
.cmddata = kl_spi0cmddata,
#endif
.send = spi_send,
#ifdef CONFIG_SPI_EXCHANGE
.exchange = spi_exchange,
#else
.sndblock = spi_sndblock,
.recvblock = spi_recvblock,
#endif
.registercallback = 0, /* Not supported */
};
static struct kl_spidev_s g_spi0dev =
{
.spidev = { &g_spi0ops },
.spibase = KL_SPI0_BASE,
};
#endif
#ifdef CONFIG_KL_SPI1
static const struct spi_ops_s g_spi1ops =
{
.lock = spi_lock,
.select = kl_spi1select,
.setfrequency = spi_setfrequency,
.setmode = spi_setmode,
.setbits = spi_setbits,
.status = kl_spi1status,
#ifdef CONFIG_SPI_CMDDATA
.cmddata = kl_spi1cmddata,
#endif
.send = spi_send,
#ifdef CONFIG_SPI_EXCHANGE
.exchange = spi_exchange,
#else
.sndblock = spi_sndblock,
.recvblock = spi_recvblock,
#endif
.registercallback = 0,
};
static struct kl_spidev_s g_spi1dev =
{
.spidev = { &g_spi1ops },
.spibase = KL_SPI1_BASE,
};
#endif
/****************************************************************************
* Private Functions
****************************************************************************/
/************************************************************************************
* Name: spi_getreg
*
* Description:
* Get the contents of the SPI register at offset
*
* Input Parameters:
* priv - private SPI device structure
* offset - offset to the register of interest
*
* Returned Value:
* The contents of the 16-bit register
*
************************************************************************************/
static inline uint8_t spi_getreg(FAR struct kl_spidev_s *priv, uint8_t offset)
{
return getreg8(priv->spibase + offset);
}
/************************************************************************************
* Name: spi_putreg
*
* Description:
* Write a 16-bit value to the SPI register at offset
*
* Input Parameters:
* priv - private SPI device structure
* offset - offset to the register of interest
* value - the 16-bit value to be written
*
* Returned Value:
* The contents of the 16-bit register
*
************************************************************************************/
static inline void spi_putreg(FAR struct kl_spidev_s *priv, uint8_t offset,
uint8_t value)
{
putreg8(value, priv->spibase + offset);
}
/************************************************************************************
* 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 kl_spidev_s *priv = (FAR struct kl_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;
}
/************************************************************************************
* 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 kl_spidev_s *priv = (FAR struct kl_spidev_s *)dev;
uint32_t divisor;
uint32_t actual;
unsigned int spr;
unsigned int sppr;
/* Check if the requested frequence is the same as the frequency selection */
if (priv->frequency == frequency)
{
/* We are already at this frequency. Return the actual. */
return priv->actual;
}
/* The clock source for the SPI baud rate generator is the bus clock. We
* need to pick a prescaler value 1, 2, 3, 4, 5, 6, 7, or 8 and then a
* divisor in the range {2, 4, 8, 16, 32, 64, 128, 256, or 512).
*
*
* BaudRateDivisor = (SPPR + 1) <20> 2^(SPR + 1)
* BaudRate = BusClock / BaudRateDivisor
*
* The strategy is to pick the smallest divisor that yields an in-range
* solution. I am not sure if this *always* results in an optimal solution.
* But consider, for example, with a 24Mhz bus clock and a target of 400KHz
*
* target divisor is 24,000,000 / 400,000 = 60
* spr = 1 -> sppr = 60 / (1 << 1) = 30 -> out of range
* spr = 2 -> sppr = 60 / (1 << 2) = 15 -> out of range
* spr = 3 -> sppr = 60 / (1 << 3) = 7 -> actual = 24000000 / 7 * 8 = 428571
* spr = 4 -> sppr = 60 / (1 << 4) = 3 -> actual = 24000000 / 3 * 16 = 500000
* spr = 5 -> sppr = 60 / (1 << 5) = 1 -> actual = 24000000 / 1 * 32 = 750000
*/
divisor = BOARD_BUSCLK_FREQ / frequency;
for (spr = 1; spr < 10; spr++)
{
sppr = divisor / (1 << spr);
if (sppr < 9)
{
break;
}
}
/* Handle failures to find a solution by forcing spr to the maximum value */
DEBUGASSERT(spr < 10);
if (spr > 9)
{
spr = 9;
sppr = divisor / 512;
}
/* Write the new dividers to the BR register */
spi_putreg(priv, KL_SPI_BR_OFFSET, SPI_BR_SPR_DIV(spr) | SPI_BR_SPPR(sppr));
/* Calculate the actual divisor and frequency */
divisor = sppr * (1 << spr);
actual = BOARD_BUSCLK_FREQ / divisor;
/* Save the frequency setting */
priv->frequency = frequency;
priv->actual = actual;
spidbg("Frequency %d->%d\n", frequency, actual);
return actual;
}
/************************************************************************************
* Name: spi_setmode
*
* Description:
* Set the SPI mode. see enum spi_mode_e for mode definitions
*
* Input Parameters:
* dev - Device-specific state data
* mode - The SPI mode requested
*
* Returned Value:
* Returns the actual frequency selected
*
************************************************************************************/
static void spi_setmode(FAR struct spi_dev_s *dev, enum spi_mode_e mode)
{
FAR struct kl_spidev_s *priv = (FAR struct kl_spidev_s *)dev;
uint8_t regval;
spivdbg("mode=%d\n", mode);
/* Has the mode changed? */
if (mode != priv->mode)
{
/* Yes... Set C1 appropriately */
regval = spi_getreg(priv, KL_SPI_C1_OFFSET);
regval &= ~(SPI_C1_CPOL | SPI_C1_CPHA);
switch (mode)
{
case SPIDEV_MODE0: /* CPOL=0; CPHA=0 */
break;
case SPIDEV_MODE1: /* CPOL=0; CPHA=1 */
regval |= SPI_C1_CPHA;
break;
case SPIDEV_MODE2: /* CPOL=1; CPHA=0 */
regval |= SPI_C1_CPOL;
break;
case SPIDEV_MODE3: /* CPOL=1; CPHA=1 */
regval |= (SPI_C1_CPOL | SPI_C1_CPHA);
break;
default:
DEBUGASSERT(FALSE);
return;
}
spi_putreg(priv, KL_SPI_C1_OFFSET, regval);
/* Save the mode so that subsequent re-configuratins will be faster */
priv->mode = mode;
}
}
/************************************************************************************
* Name: spi_setbits
*
* Description:
* Set the number of bits per word.
*
* Input Parameters:
* dev - Device-specific state data
* nbits - The number of bits requested
*
* Returned Value:
* None
*
************************************************************************************/
static void spi_setbits(FAR struct spi_dev_s *dev, int nbits)
{
/* Only 8-bit mode is supported */
DEBUGASSERT(nbits == 8);
}
/************************************************************************************
* 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 kl_spidev_s *priv = (FAR struct kl_spidev_s *)dev;
/* Make sure that the transmit buffer is empty */
while ((spi_getreg(priv, KL_SPI_S_OFFSET) & SPI_S_SPTEF) == 0);
/* Write the data to transmitted to the SPI Data Register */
spi_putreg(priv, KL_SPI_D_OFFSET, (uint8_t)wd);
/* Wait for the SPRF bit in the SPI Status Register to be set to 1. SPRF is set
* at the completion of an SPI transfer to indicate that received data may be read
* from the SPI data registr
*/
while ((spi_getreg(priv, KL_SPI_S_OFFSET) & SPI_S_SPRF) == 0);
/* Return the data */
return (uint16_t)spi_getreg(priv, KL_SPI_D_OFFSET);
}
/************************************************************************************
* Name: spi_exchange
*
* Description:
* Exchange a block of data on SPI without using DMA
*
* Input Parameters:
* dev - Device-specific state data
* txbuffer - A pointer to the buffer of data to be sent
* rxbuffer - A pointer to a buffer in which to receive data
* nwords - the length of data to be exchaned 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
*
************************************************************************************/
static void spi_exchange(FAR struct spi_dev_s *dev, FAR const void *txbuffer,
FAR void *rxbuffer, size_t nwords)
{
FAR struct kl_spidev_s *priv = (FAR struct kl_spidev_s *)dev;
FAR uint8_t *rxptr = (FAR uint8_t *)rxbuffer;
FAR uint8_t *txptr = (FAR uint8_t *)txbuffer;
uint8_t data;
spivdbg("txbuffer=%p rxbuffer=%p nwords=%d\n", txbuffer, rxbuffer, nwords);
/* Loop, sending each word in the user-provied data buffer. */
for (; nwords > 0; nwords--)
{
/* Get the data to send (0xff if there is no data source) */
if (txptr)
{
data = (uint8_t)*txptr++;
}
else
{
data = 0xff;
}
/* Wait for any previous data written to the TDR to be transferred
* to the serializer.
*/
while ((spi_getreg(priv, KL_SPI_S_OFFSET) & SPI_S_SPTEF) == 0);
/* Write the data to transmitted to the Transmit Data Register (TDR) */
spi_putreg(priv, KL_SPI_D_OFFSET, data);
/* Wait for the read data to be available in the data regiter */
while ((spi_getreg(priv, KL_SPI_S_OFFSET) & SPI_S_SPRF) == 0);
/* Read the received data from the SPI Data Register..
* TODO: The following only works if nbits <= 8.
*/
data = spi_getreg(priv, KL_SPI_D_OFFSET);
if (rxptr)
{
*rxptr++ = (uint8_t)data;
}
}
}
/****************************************************************************
* Name: spi_sndblock
*
* Description:
* Send a block of data on SPI
*
* Input Parameters:
* dev - Device-specific state data
* txbuffer - 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
*
************************************************************************************/
#ifndef CONFIG_SPI_EXCHANGE
static void spi_sndblock(FAR struct spi_dev_s *dev, FAR const void *txbuffer,
size_t nwords)
{
spivdbg("txbuffer=%p nwords=%d\n", txbuffer, nwords);
return spi_exchange(dev, txbuffer, NULL, nwords);
}
#endif
/************************************************************************************
* Name: spi_recvblock
*
* Description:
* Receive a block of data from SPI
*
* Input Parameters:
* dev - Device-specific state data
* rxbuffer - 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
*
************************************************************************************/
#ifndef CONFIG_SPI_EXCHANGE
static void spi_recvblock(FAR struct spi_dev_s *dev, FAR void *rxbuffer, size_t nwords)
{
spivdbg("rxbuffer=%p nwords=%d\n", rxbuffer, nwords);
return spi_exchange(dev, NULL, rxbuffer, nwords);
}
#endif
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: up_spiinitialize
*
* 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 *up_spiinitialize(int port)
{
FAR struct kl_spidev_s *priv;
uint32_t regval;
/* Configure multiplexed pins as connected on the board. Chip select pins
* must be configured by board-specific logic. Most SPI pins multiple,
* alternative pin selection. Definitions in the board.h file must be\
* provided to resolve the board-specific pin configuration like:
*
* #define PIN_SPI0_SCK PIN_SPI0_SCK_1
*/
#ifdef CONFIG_KL_SPI0
if (port == 0)
{
priv = &g_spi0dev;
/* Configure pins for SPI0 */
kl_configgpio(PIN_SPI0_SCK);
kl_configgpio(PIN_SPI0_MISO);
kl_configgpio(PIN_SPI0_MOSI);
/* Enable clocking */
regval = getreg32(KL_SIM_SCGC4);
regval |= SIM_SCGC4_SPI0;
putreg32(regval, KL_SIM_SCGC4);
}
else
#endif
#ifdef CONFIG_KL_SPI1
if (port == 1)
{
priv = &g_spi1dev;
/* Configure pins for SPI1 */
kl_configgpio(PIN_SPI1_SCK);
kl_configgpio(PIN_SPI1_MISO);
kl_configgpio(PIN_SPI1_MOSI);
/* Enable clocking */
regval = getreg32(KL_SIM_SCGC4);
regval |= SIM_SCGC4_SPI1;
putreg32(regval, KL_SIM_SCGC4);
}
else
#endif
{
spidbg("ERROR: Port %d not configured\n", port);
return NULL;
}
/* Configure master mode, select mode 0, MSB first. Disable interrupts. */
spi_putreg(priv, KL_SPI_C1_OFFSET, SPI_C1_SPE | SPI_C1_MSTR);
/* Disable interrupts, DMA, bidirectional mode, stop-in-wait mode, enable
* master mode fault detection
*/
spi_putreg(priv, KL_SPI_C2_OFFSET, 0);
/* Set the initial SPI configuration */
priv->frequency = 0;
priv->mode = SPIDEV_MODE0;
/* 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 */
sem_init(&priv->exclsem, 0, 1);
return &priv->spidev;
}
#endif /* CONFIG_KL_SPI0 || CONFIG_KL_SPI1 */
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