diff options
Diffstat (limited to 'drivers/spi/sh_spi.c')
| -rw-r--r-- | drivers/spi/sh_spi.c | 261 |
1 files changed, 261 insertions, 0 deletions
diff --git a/drivers/spi/sh_spi.c b/drivers/spi/sh_spi.c new file mode 100644 index 0000000..ba43bec --- /dev/null +++ b/drivers/spi/sh_spi.c @@ -0,0 +1,261 @@ +/* + * SH SPI driver + * + * Copyright (C) 2011 Renesas Solutions Corp. + * + * 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; version 2 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, write to the Free Software + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + * + */ + +#include <common.h> +#include <malloc.h> +#include <spi.h> +#include <asm/io.h> +#include "sh_spi.h" + +static void sh_spi_write(unsigned long data, unsigned long *reg) +{ + writel(data, reg); +} + +static unsigned long sh_spi_read(unsigned long *reg) +{ + return readl(reg); +} + +static void sh_spi_set_bit(unsigned long val, unsigned long *reg) +{ + unsigned long tmp; + + tmp = sh_spi_read(reg); + tmp |= val; + sh_spi_write(tmp, reg); +} + +static void sh_spi_clear_bit(unsigned long val, unsigned long *reg) +{ + unsigned long tmp; + + tmp = sh_spi_read(reg); + tmp &= ~val; + sh_spi_write(tmp, reg); +} + +static void clear_fifo(struct sh_spi *ss) +{ + sh_spi_set_bit(SH_SPI_RSTF, &ss->regs->cr2); + sh_spi_clear_bit(SH_SPI_RSTF, &ss->regs->cr2); +} + +static int recvbuf_wait(struct sh_spi *ss) +{ + while (sh_spi_read(&ss->regs->cr1) & SH_SPI_RBE) { + if (ctrlc()) + return 1; + udelay(10); + } + return 0; +} + +static int write_fifo_empty_wait(struct sh_spi *ss) +{ + while (!(sh_spi_read(&ss->regs->cr1) & SH_SPI_TBE)) { + if (ctrlc()) + return 1; + udelay(10); + } + return 0; +} + +void spi_init(void) +{ +} + +struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs, + unsigned int max_hz, unsigned int mode) +{ + struct sh_spi *ss; + + if (!spi_cs_is_valid(bus, cs)) + return NULL; + + ss = malloc(sizeof(struct spi_slave)); + if (!ss) + return NULL; + + ss->slave.bus = bus; + ss->slave.cs = cs; + ss->regs = (struct sh_spi_regs *)CONFIG_SH_SPI_BASE; + + /* SPI sycle stop */ + sh_spi_write(0xfe, &ss->regs->cr1); + /* CR1 init */ + sh_spi_write(0x00, &ss->regs->cr1); + /* CR3 init */ + sh_spi_write(0x00, &ss->regs->cr3); + + clear_fifo(ss); + + /* 1/8 clock */ + sh_spi_write(sh_spi_read(&ss->regs->cr2) | 0x07, &ss->regs->cr2); + udelay(10); + + return &ss->slave; +} + +void spi_free_slave(struct spi_slave *slave) +{ + struct sh_spi *spi = to_sh_spi(slave); + + free(spi); +} + +int spi_claim_bus(struct spi_slave *slave) +{ + return 0; +} + +void spi_release_bus(struct spi_slave *slave) +{ + struct sh_spi *ss = to_sh_spi(slave); + + sh_spi_write(sh_spi_read(&ss->regs->cr1) & + ~(SH_SPI_SSA | SH_SPI_SSDB | SH_SPI_SSD), &ss->regs->cr1); +} + +static int sh_spi_send(struct sh_spi *ss, const unsigned char *tx_data, + unsigned int len, unsigned long flags) +{ + int i, cur_len, ret = 0; + int remain = (int)len; + unsigned long tmp; + + if (len >= SH_SPI_FIFO_SIZE) + sh_spi_set_bit(SH_SPI_SSA, &ss->regs->cr1); + + while (remain > 0) { + cur_len = (remain < SH_SPI_FIFO_SIZE) ? + remain : SH_SPI_FIFO_SIZE; + for (i = 0; i < cur_len && + !(sh_spi_read(&ss->regs->cr4) & SH_SPI_WPABRT) && + !(sh_spi_read(&ss->regs->cr1) & SH_SPI_TBF); + i++) + sh_spi_write(tx_data[i], &ss->regs->tbr_rbr); + + cur_len = i; + + if (sh_spi_read(&ss->regs->cr4) & SH_SPI_WPABRT) { + /* Abort the transaction */ + flags |= SPI_XFER_END; + sh_spi_set_bit(SH_SPI_WPABRT, &ss->regs->cr4); + ret = 1; + break; + } + + remain -= cur_len; + tx_data += cur_len; + + if (remain > 0) + write_fifo_empty_wait(ss); + } + + if (flags & SPI_XFER_END) { + tmp = sh_spi_read(&ss->regs->cr1); + tmp = tmp & ~(SH_SPI_SSD | SH_SPI_SSDB); + sh_spi_write(tmp, &ss->regs->cr1); + sh_spi_set_bit(SH_SPI_SSA, &ss->regs->cr1); + udelay(100); + write_fifo_empty_wait(ss); + } + + return ret; +} + +static int sh_spi_receive(struct sh_spi *ss, unsigned char *rx_data, + unsigned int len, unsigned long flags) +{ + int i; + unsigned long tmp; + + if (len > SH_SPI_MAX_BYTE) + sh_spi_write(SH_SPI_MAX_BYTE, &ss->regs->cr3); + else + sh_spi_write(len, &ss->regs->cr3); + + tmp = sh_spi_read(&ss->regs->cr1); + tmp = tmp & ~(SH_SPI_SSD | SH_SPI_SSDB); + sh_spi_write(tmp, &ss->regs->cr1); + sh_spi_set_bit(SH_SPI_SSA, &ss->regs->cr1); + + for (i = 0; i < len; i++) { + if (recvbuf_wait(ss)) + return 0; + + rx_data[i] = (unsigned char)sh_spi_read(&ss->regs->tbr_rbr); + } + sh_spi_write(0, &ss->regs->cr3); + + return 0; +} + +int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *dout, + void *din, unsigned long flags) +{ + struct sh_spi *ss = to_sh_spi(slave); + const unsigned char *tx_data = dout; + unsigned char *rx_data = din; + unsigned int len = bitlen / 8; + int ret = 0; + + if (flags & SPI_XFER_BEGIN) + sh_spi_write(sh_spi_read(&ss->regs->cr1) & ~SH_SPI_SSA, + &ss->regs->cr1); + + if (tx_data) + ret = sh_spi_send(ss, tx_data, len, flags); + + if (ret == 0 && rx_data) + ret = sh_spi_receive(ss, rx_data, len, flags); + + if (flags & SPI_XFER_END) { + sh_spi_set_bit(SH_SPI_SSD, &ss->regs->cr1); + udelay(100); + + sh_spi_clear_bit(SH_SPI_SSA | SH_SPI_SSDB | SH_SPI_SSD, + &ss->regs->cr1); + clear_fifo(ss); + } + + return ret; +} + +int spi_cs_is_valid(unsigned int bus, unsigned int cs) +{ + /* This driver supports "bus = 0" and "cs = 0" only. */ + if (!bus && !cs) + return 1; + else + return 0; +} + +void spi_cs_activate(struct spi_slave *slave) +{ + +} + +void spi_cs_deactivate(struct spi_slave *slave) +{ + +} + |