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/*
* Copyright © 2013 Keith Packard <keithp@keithp.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
*/
#include <ao.h>
static uint8_t ao_spi_mutex[LPC_NUM_SPI];
static struct lpc_ssp * const ao_lpc_ssp[LPC_NUM_SPI] = { &lpc_ssp0, &lpc_ssp1 };
#define spi_loop(len, put, get) do { \
while (len--) { \
/* send a byte */ \
lpc_ssp->dr = put; \
/* wait for the received byte to appear */ \
while ((lpc_ssp->sr & (1 << LPC_SSP_SR_RNE)) == 0) \
; \
/* receive a byte */ \
get lpc_ssp->dr; \
} \
/* Wait for the SSP to go idle (it already should be) */ \
while (lpc_ssp->sr & (1 << LPC_SSP_SR_BSY)); \
} while (0)
void
ao_spi_send(const void *block, uint16_t len, uint8_t id)
{
struct lpc_ssp *lpc_ssp = ao_lpc_ssp[id];
const uint8_t *o = block;
spi_loop(len, *o++, (void));
}
void
ao_spi_send_fixed(uint8_t value, uint16_t len, uint8_t id)
{
struct lpc_ssp *lpc_ssp = ao_lpc_ssp[id];
spi_loop(len, value, (void));
}
void
ao_spi_recv(void *block, uint16_t len, uint8_t id)
{
struct lpc_ssp *lpc_ssp = ao_lpc_ssp[id];
uint8_t *i = block;
spi_loop(len, 0xff, *i++ =);
}
void
ao_spi_duplex(const void *out, void *in, uint16_t len, uint8_t id)
{
struct lpc_ssp *lpc_ssp = ao_lpc_ssp[id];
const uint8_t *o = out;
uint8_t *i = in;
spi_loop(len, *o++, *i++ =);
}
void
ao_spi_get(uint8_t id, uint32_t speed)
{
struct lpc_ssp *lpc_ssp = ao_lpc_ssp[id];
ao_mutex_get(&ao_spi_mutex[id]);
/* Set the clock prescale */
lpc_ssp->cpsr = speed;
}
void
ao_spi_put(uint8_t id)
{
ao_mutex_put(&ao_spi_mutex[id]);
}
static void
ao_spi_channel_init(uint8_t id)
{
struct lpc_ssp *lpc_ssp = ao_lpc_ssp[id];
uint8_t d;
/* Clear interrupt registers */
lpc_ssp->imsc = 0;
lpc_ssp->ris = 0;
lpc_ssp->mis = 0;
lpc_ssp->cr0 = ((LPC_SSP_CR0_DSS_8 << LPC_SSP_CR0_DSS) |
(LPC_SSP_CR0_FRF_SPI << LPC_SSP_CR0_FRF) |
(0 << LPC_SSP_CR0_CPOL) |
(0 << LPC_SSP_CR0_CPHA) |
(0 << LPC_SSP_CR0_SCR));
/* Enable the device */
lpc_ssp->cr1 = ((0 << LPC_SSP_CR1_LBM) |
(1 << LPC_SSP_CR1_SSE) |
(LPC_SSP_CR1_MS_MASTER << LPC_SSP_CR1_MS) |
(0 << LPC_SSP_CR1_SOD));
/* Drain the receive fifo */
for (d = 0; d < LPC_SSP_FIFOSIZE; d++)
(void) lpc_ssp->dr;
}
void
ao_spi_init(void)
{
#if HAS_SPI_0
/* Configure pins */
#if SPI_SCK0_P0_6
lpc_ioconf.pio0_6 = ao_lpc_alternate(LPC_IOCONF_FUNC_PIO0_6_SCK0);
#define HAS_SCK0
#endif
#if SPI_SCK0_P0_10
lpc_ioconf.pio0_10 = ao_lpc_alternate(LPC_IOCONF_FUNC_PIO0_10_SCK0);
#define HAS_SCK0
#endif
#if SPI_SCK0_P1_29
lpc_ioconf.pio1_29 = ao_lpc_alternate(LPC_IOCONF_FUNC_PIO1_29_SCK0);
#define HAS_SCK0
#endif
#ifndef HAS_SCK0
#error "No pin specified for SCK0"
#endif
lpc_ioconf.pio0_8 = ao_lpc_alternate(LPC_IOCONF_FUNC_MISO0);
lpc_ioconf.pio0_9 = ao_lpc_alternate(LPC_IOCONF_FUNC_MOSI0);
/* Enable the device */
lpc_scb.sysahbclkctrl |= (1 << LPC_SCB_SYSAHBCLKCTRL_SSP0);
/* Turn on the clock */
lpc_scb.ssp0clkdiv = 1;
/* Reset the device */
lpc_scb.presetctrl &= ~(1 << LPC_SCB_PRESETCTRL_SSP0_RST_N);
lpc_scb.presetctrl |= (1 << LPC_SCB_PRESETCTRL_SSP0_RST_N);
ao_spi_channel_init(0);
#endif
#if HAS_SPI_1
#if SPI_SCK1_P1_15
lpc_ioconf.pio1_15 = ao_lpc_alternate(LPC_IOCONF_FUNC_PIO1_15_SCK1);
#define HAS_SCK1
#endif
#if SPI_SCK1_P1_20
lpc_ioconf.pio1_20 = ao_lpc_alternate(LPC_IOCONF_FUNC_PIO1_20_SCK1);
#define HAS_SCK1
#endif
#ifndef HAS_SCK1
#error "No pin specified for SCK1"
#endif
#if SPI_MISO1_P0_22
lpc_ioconf.pio0_22 = ao_lpc_alternate(LPC_IOCONF_FUNC_PIO0_22_MISO1);
#define HAS_MISO1
#endif
#if SPI_MISO1_P1_21
lpc_ioconf.pio1_21 = ao_lpc_alternate(LPC_IOCONF_FUNC_PIO1_21_MISO1);
#define HAS_MISO1
#endif
#ifndef HAS_MISO1
#error "No pin specified for MISO1"
#endif
#if SPI_MOSI1_P0_21
lpc_ioconf.pio0_21 = ao_lpc_alternate(LPC_IOCONF_FUNC_PIO0_21_MOSI1);
#define HAS_MOSI1
#endif
#if SPI_MOSI1_P1_22
lpc_ioconf.pio1_22 = ao_lpc_alternate(LPC_IOCONF_FUNC_PIO1_22_MOSI1);
#define HAS_MOSI1
#endif
#ifndef HAS_MOSI1
#error "No pin specified for MOSI1"
#endif
/* Enable the device */
lpc_scb.sysahbclkctrl |= (1 << LPC_SCB_SYSAHBCLKCTRL_SSP1);
/* Turn on the clock */
lpc_scb.ssp1clkdiv = 1;
/* Reset the device */
lpc_scb.presetctrl &= ~(1 << LPC_SCB_PRESETCTRL_SSP1_RST_N);
lpc_scb.presetctrl |= (1 << LPC_SCB_PRESETCTRL_SSP1_RST_N);
ao_spi_channel_init(1);
#endif /* HAS_SPI_1 */
}
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