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/*
* ChipCity CC32RS512 SPI controller driver
*
* Copyright (C) 2012 Harald Welte <laforge@gnumonks.org>
*
* 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 or
* (at your option) version 3 of the License.
*
* 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, see <http://www.gnu.org/licenses/>.
*/
#include <errno.h>
#include "cc32_sysc.h"
#include "cc32_spi.h"
#include "cc32_gpio.h"
#include "board.h"
#define CC32_SPI_BASE 0x0f9800
enum cc32_spi_reg {
SPICON2 = 0x08,
SPIDAT = 0x0C,
SPISTS = 0x10,
SPIMSK = 0x14,
SPIDMALEN = 0x20,
SPIDMACON = 0x28,
SPIDMASTS = 0x2C,
SPIDMAMSK = 0x30,
SPITBUF = 0x40,
SPIRBUF = 0x44,
SPIDMARPT = 0x48,
};
#define SPI_REG(x) (volatile uint32_t *)((uint8_t *)CC32_SPI_BASE + x)
#define SPICON2_RUNEN (1 << 7)
#define SPISTS_BOVER (1 << 0)
#define SPISTS_MODF (1 << 1)
#define SPIMSK_MBOVER (1 << 0)
#define SPIDMACON_FULL_DUPLEX (0 << 1)
#define SPIDMACON_TX_ONLY (1 << 1)
#define SPIDMACON_RX_ONLY (2 << 1)
#define SPIDMACON_START (1 << 0)
#define SPIDMASTS_OVER (1 << 0)
#define SPIDMASTS_BOVER (1 << 1)
#define SPIDMAMSK_MOVER (1 << 0)
#define SPIDMAMSK_MBOVER (1 << 1)
int cc32_spi_init(uint8_t cpol, uint8_t cpha, uint8_t divide_2n)
{
uint32_t val;
cc32_sysc_clk_enable(CLK_SPI);
/* configure GPIOs as output */
cc32_gpio_output(24, 1);
cc32_gpio_output(25, 1);
cc32_gpio_output(26, 1);
/* configure P3 as SPI function */
cc32_gpio_alt(CC32_GPIO_P3, CC32_GPIO_FUNC2);
/* configure GPIO11 as output (SPI_nCS) */
cc32_gpio_output(BOARD_GPIO_SPI_NCS, 1);
/* set to 1 (disable) */
cc32_gpio_set(BOARD_GPIO_SPI_NCS, 1);
if (divide_2n < 2 || divide_2n > 256)
return -EINVAL;
val = ((cpol & 1) << 0) | ((cpha & 1) << 1) | ((divide_2n-1) << 2) | SPICON2_RUNEN;
/* this is an undocumented value, but without it seems the SPI
* is not working! */
*SPI_REG(SPICON2) = val | 0x60;
return 0;
}
int cc32_spi_xcv_byte(uint8_t tx)
{
*SPI_REG(SPIDAT) = tx;
while (!(*SPI_REG(SPISTS) & SPISTS_BOVER)) { }
return *SPI_REG(SPIDAT);
}
void cc32_spi_ncs(uint8_t high)
{
cc32_gpio_set(BOARD_GPIO_SPI_NCS, high);
}
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