diff --git a/arch/nios2/include/asm/spi.h b/arch/nios2/include/asm/spi.h new file mode 100644 index 0000000..4e576b9 --- /dev/null +++ b/arch/nios2/include/asm/spi.h @@ -0,0 +1,21 @@ +#ifndef __ALTERA_SPI_H_ +#define __ALTERA_SPI_H_ + +#include + +struct spi_altera_master { + int num_chipselect; + int spi_mode; + int databits; + int speed; +}; + +struct altera_spi { + struct spi_master master; + int databits; + int speed; + int mode; + void __iomem *regs; +}; + +#endif /*__ALTERA_SPI_H_*/ diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig index 9ab03f6..c72493c 100644 --- a/drivers/spi/Kconfig +++ b/drivers/spi/Kconfig @@ -19,4 +19,9 @@ depends on ARCH_IMX51 || ARCH_IMX53 default y +config DRIVER_SPI_ALTERA + bool "Altera SPI Master driver" + depends on NIOS2 + depends on SPI + endmenu diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile index b2b2f67..90e141d 100644 --- a/drivers/spi/Makefile +++ b/drivers/spi/Makefile @@ -1,2 +1,3 @@ obj-$(CONFIG_SPI) += spi.o obj-$(CONFIG_DRIVER_SPI_IMX) += imx_spi.o +obj-$(CONFIG_DRIVER_SPI_ALTERA) += altera_spi.o diff --git a/drivers/spi/altera_spi.c b/drivers/spi/altera_spi.c new file mode 100644 index 0000000..2c02d7a --- /dev/null +++ b/drivers/spi/altera_spi.c @@ -0,0 +1,227 @@ +/* + * (C) Copyright 2011 - Franck JULLIEN + * + * 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 +#include +#include +#include +#include +#include +#include + +static int altera_spi_setup(struct spi_device *spi) +{ + struct spi_master *master = spi->master; + struct device_d spi_dev = spi->dev; + struct altera_spi *altera_spi = container_of(master, struct altera_spi, master); + + if (spi->bits_per_word != altera_spi->databits) { + dev_err(master->dev, " master doesn't support %d bits per word requested by %s\n", + spi->bits_per_word, spi_dev.name); + return -1; + } + + if ((spi->mode & (SPI_CPHA | SPI_CPOL)) != altera_spi->mode) { + dev_err(master->dev, " master doesn't support SPI_MODE%d requested by %s\n", + spi->mode & (SPI_CPHA | SPI_CPOL), spi_dev.name); + return -1; + } + + if (spi->max_speed_hz < altera_spi->speed) { + dev_err(master->dev, " frequency is too high for %s\n", spi_dev.name); + return -1; + } + + dev_dbg(master->dev, " mode 0x%08x, bits_per_word: %d, speed: %d\n", + spi->mode, spi->bits_per_word, altera_spi->speed); + + return 0; +} + + +static unsigned int altera_spi_xchg_single(struct altera_spi *altera_spi, unsigned int data) +{ + struct nios_spi *nios_spi = altera_spi->regs; + + while (!(readl(&nios_spi->status) & NIOS_SPI_TRDY)); + writel(data, &nios_spi->txdata); + + while (!(readl(&nios_spi->status) & NIOS_SPI_RRDY)); + + return readl(&nios_spi->rxdata); +} + +/* + * When using SPI_CS_HIGH devices, only one device is allowed to be + * connected to the Altera SPI master. This limitation is due to the + * emulation of an active high CS by writing 0 to the slaveselect register + * (this produce a '1' to all CS pins). + */ + +static void altera_spi_cs_active(struct spi_device *spi) +{ + struct altera_spi *altera_spi = container_of(spi->master, struct altera_spi, master); + struct nios_spi *nios_spi = altera_spi->regs; + uint32_t tmp; + + if (spi->mode & SPI_CS_HIGH) { + tmp = readw(&nios_spi->control); + writew(tmp & ~NIOS_SPI_SSO, &nios_spi->control); + writel(0, &nios_spi->slaveselect); + } else { + writel(1 << spi->chip_select, &nios_spi->slaveselect); + tmp = readl(&nios_spi->control); + writel(tmp | NIOS_SPI_SSO, &nios_spi->control); + } +} + +static void altera_spi_cs_inactive(struct spi_device *spi) +{ + struct altera_spi *altera_spi = container_of(spi->master, struct altera_spi, master); + struct nios_spi *nios_spi = altera_spi->regs; + uint32_t tmp; + + if (spi->mode & SPI_CS_HIGH) { + writel(1 << spi->chip_select, &nios_spi->slaveselect); + tmp = readl(&nios_spi->control); + writel(tmp | NIOS_SPI_SSO, &nios_spi->control); + } else { + tmp = readw(&nios_spi->control); + writew(tmp & ~NIOS_SPI_SSO, &nios_spi->control); + } +} + +static unsigned altera_spi_do_xfer(struct spi_device *spi, struct spi_transfer *t) +{ + struct altera_spi *altera_spi = container_of(spi->master, struct altera_spi, master); + int word_len = spi->bits_per_word; + unsigned retval = 0; + u32 txval; + u32 rxval; + + word_len = spi->bits_per_word; + + if (word_len <= 8) { + const u8 *txbuf = t->tx_buf; + u8 *rxbuf = t->rx_buf; + int i = 0; + + while (i < t->len) { + txval = txbuf ? txbuf[i] : 0; + rxval = altera_spi_xchg_single(altera_spi, txval); + if (rxbuf) + rxbuf[i] = rxval; + i++; + retval++; + } + } else if (word_len <= 16) { + const u16 *txbuf = t->tx_buf; + u16 *rxbuf = t->rx_buf; + int i = 0; + + while (i < t->len >> 1) { + txval = txbuf ? txbuf[i] : 0; + rxval = altera_spi_xchg_single(altera_spi, txval); + if (rxbuf) + rxbuf[i] = rxval; + i++; + retval += 2; + } + } else if (word_len <= 32) { + const u32 *txbuf = t->tx_buf; + u32 *rxbuf = t->rx_buf; + int i = 0; + + while (i < t->len >> 2) { + txval = txbuf ? txbuf[i] : 0; + rxval = altera_spi_xchg_single(altera_spi, txval); + if (rxbuf) + rxbuf[i] = rxval; + i++; + retval += 4; + } + } + + return retval; +} + +static int altera_spi_transfer(struct spi_device *spi, struct spi_message *mesg) +{ + struct altera_spi *altera_spi = container_of(spi->master, struct altera_spi, master); + struct nios_spi *nios_spi = altera_spi->regs; + struct spi_transfer *t; + + altera_spi_cs_active(spi); + + mesg->actual_length = 0; + + list_for_each_entry(t, &mesg->transfers, transfer_list) { + mesg->actual_length += altera_spi_do_xfer(spi, t); + } + + /* Wait the end of any pending transfer */ + while ((readl(&nios_spi->status) & NIOS_SPI_TMT) == 0); + + altera_spi_cs_inactive(spi); + + return 0; +} + +static int altera_spi_probe(struct device_d *dev) +{ + struct spi_master *master; + struct altera_spi *altera_spi; + struct spi_altera_master *pdata = dev->platform_data; + struct nios_spi *nios_spi; + + altera_spi = xzalloc(sizeof(*altera_spi)); + + master = &altera_spi->master; + master->dev = dev; + + master->setup = altera_spi_setup; + master->transfer = altera_spi_transfer; + master->num_chipselect = pdata->num_chipselect; + + altera_spi->regs = dev_request_mem_region(dev, 0); + altera_spi->databits = pdata->databits; + altera_spi->speed = pdata->speed; + altera_spi->mode = pdata->spi_mode; + + nios_spi = altera_spi->regs; + writel(0, &nios_spi->slaveselect); + writel(0, &nios_spi->control); + + spi_register_master(master); + + return 0; +} + +static struct driver_d altera_spi_driver = { + .name = "altera_spi", + .probe = altera_spi_probe, +}; + +static int altera_spi_driver_init(void) +{ + return register_driver(&altera_spi_driver); +} + +device_initcall(altera_spi_driver_init);