OMAP3: SPI driver

CC: Ruslan N. Araslanov <byaaka@yandex.ru>
Signed-off-by: Ruslan Araslanov <ruslan.araslanov@vitecmm.com>
Signed-off-by: Sandeep Paulraj <s-paulraj@ti.com>

1 files changed, 352 insertions, 0 deletions

diff --git a/drivers/spi/omap3_spi.c b/drivers/spi/omap3_spi.c
new file mode 100644
index 0000000..af12c0e
--- /dev/null
+++ b/drivers/spi/omap3_spi.c
@@ -0,0 +1,352 @@
+/*
+ * Copyright (C) 2010 Dirk Behme <dirk.behme@googlemail.com>
+ *
+ * Driver for McSPI controller on OMAP3. Based on davinci_spi.c
+ * Copyright (C) 2009 Texas Instruments Incorporated - http://www.ti.com/
+ *
+ * Copyright (C) 2007 Atmel Corporation
+ *
+ * Parts taken from linux/drivers/spi/omap2_mcspi.c
+ * Copyright (C) 2005, 2006 Nokia Corporation
+ *
+ * Modified by Ruslan Araslanov <ruslan.araslanov@vitecmm.com>
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * 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 <common.h>
+#include <spi.h>
+#include <malloc.h>
+#include <asm/io.h>
+#include "omap3_spi.h"
+
+#define WORD_LEN	8
+#define SPI_WAIT_TIMEOUT 3000000;
+
+static void spi_reset(struct omap3_spi_slave *ds)
+{
+	unsigned int tmp;
+
+	writel(OMAP3_MCSPI_SYSCONFIG_SOFTRESET, &ds->regs->sysconfig);
+	do {
+		tmp = readl(&ds->regs->sysstatus);
+	} while (!(tmp & OMAP3_MCSPI_SYSSTATUS_RESETDONE));
+
+	writel(OMAP3_MCSPI_SYSCONFIG_AUTOIDLE |
+				 OMAP3_MCSPI_SYSCONFIG_ENAWAKEUP |
+				 OMAP3_MCSPI_SYSCONFIG_SMARTIDLE,
+				 &ds->regs->sysconfig);
+
+	writel(OMAP3_MCSPI_WAKEUPENABLE_WKEN, &ds->regs->wakeupenable);
+}
+
+void spi_init()
+{
+	/* do nothing */
+}
+
+struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
+				  unsigned int max_hz, unsigned int mode)
+{
+	struct omap3_spi_slave	*ds;
+
+	ds = malloc(sizeof(struct omap3_spi_slave));
+	if (!ds) {
+		printf("SPI error: malloc of SPI structure failed\n");
+		return NULL;
+	}
+
+	/*
+	 * OMAP3 McSPI (MultiChannel SPI) has 4 busses (modules)
+	 * with different number of chip selects (CS, channels):
+	 * McSPI1 has 4 CS (bus 0, cs 0 - 3)
+	 * McSPI2 has 2 CS (bus 1, cs 0 - 1)
+	 * McSPI3 has 2 CS (bus 2, cs 0 - 1)
+	 * McSPI4 has 1 CS (bus 3, cs 0)
+	 */
+
+	switch (bus) {
+	case 0:
+		ds->regs = (struct mcspi *)OMAP3_MCSPI1_BASE;
+		break;
+	case 1:
+		ds->regs = (struct mcspi *)OMAP3_MCSPI2_BASE;
+		break;
+	case 2:
+		ds->regs = (struct mcspi *)OMAP3_MCSPI3_BASE;
+		break;
+	case 3:
+		ds->regs = (struct mcspi *)OMAP3_MCSPI4_BASE;
+		break;
+	default:
+		printf("SPI error: unsupported bus %i. \
+			Supported busses 0 - 3\n", bus);
+		return NULL;
+	}
+	ds->slave.bus = bus;
+
+	if (((bus == 0) && (cs > 3)) ||
+			((bus == 1) && (cs > 1)) ||
+			((bus == 2) && (cs > 1)) ||
+			((bus == 3) && (cs > 0))) {
+		printf("SPI error: unsupported chip select %i \
+			on bus %i\n", cs, bus);
+		return NULL;
+	}
+	ds->slave.cs = cs;
+
+	if (max_hz > OMAP3_MCSPI_MAX_FREQ) {
+		printf("SPI error: unsupported frequency %i Hz. \
+			Max frequency is 48 Mhz\n", max_hz);
+		return NULL;
+	}
+	ds->freq = max_hz;
+
+	if (mode > SPI_MODE_3) {
+		printf("SPI error: unsupported SPI mode %i\n", mode);
+		return NULL;
+	}
+	ds->mode = mode;
+
+	return &ds->slave;
+}
+
+void spi_free_slave(struct spi_slave *slave)
+{
+	struct omap3_spi_slave *ds = to_omap3_spi(slave);
+
+	free(ds);
+}
+
+int spi_claim_bus(struct spi_slave *slave)
+{
+	struct omap3_spi_slave *ds = to_omap3_spi(slave);
+	unsigned int conf, div = 0;
+
+	/* McSPI global module configuration */
+
+	/*
+	 * setup when switching from (reset default) slave mode
+	 * to single-channel master mode
+	 */
+	spi_reset(ds);
+	conf = readl(&ds->regs->modulctrl);
+	conf &= ~(OMAP3_MCSPI_MODULCTRL_STEST | OMAP3_MCSPI_MODULCTRL_MS);
+	conf |= OMAP3_MCSPI_MODULCTRL_SINGLE;
+	writel(conf, &ds->regs->modulctrl);
+
+	/* McSPI individual channel configuration */
+
+	/* Calculate clock divisor. Valid range: 0x0 - 0xC ( /1 - /4096 ) */
+	if (ds->freq) {
+		while (div <= 0xC && (OMAP3_MCSPI_MAX_FREQ / (1 << div))
+					 > ds->freq)
+			div++;
+	} else
+		div = 0xC;
+
+	conf = readl(&ds->regs->channel[ds->slave.cs].chconf);
+
+	/* standard 4-wire master mode:	SCK, MOSI/out, MISO/in, nCS
+	 * REVISIT: this controller could support SPI_3WIRE mode.
+	 */
+	conf &= ~(OMAP3_MCSPI_CHCONF_IS|OMAP3_MCSPI_CHCONF_DPE1);
+	conf |= OMAP3_MCSPI_CHCONF_DPE0;
+
+	/* wordlength */
+	conf &= ~OMAP3_MCSPI_CHCONF_WL_MASK;
+	conf |= (WORD_LEN - 1) << 7;
+
+	/* set chipselect polarity; manage with FORCE */
+	if (!(ds->mode & SPI_CS_HIGH))
+		conf |= OMAP3_MCSPI_CHCONF_EPOL; /* active-low; normal */
+	else
+		conf &= ~OMAP3_MCSPI_CHCONF_EPOL;
+
+	/* set clock divisor */
+	conf &= ~OMAP3_MCSPI_CHCONF_CLKD_MASK;
+	conf |= div << 2;
+
+	/* set SPI mode 0..3 */
+	if (ds->mode & SPI_CPOL)
+		conf |= OMAP3_MCSPI_CHCONF_POL;
+	else
+		conf &= ~OMAP3_MCSPI_CHCONF_POL;
+	if (ds->mode & SPI_CPHA)
+		conf |= OMAP3_MCSPI_CHCONF_PHA;
+	else
+		conf &= ~OMAP3_MCSPI_CHCONF_PHA;
+
+	/* Transmit & receive mode */
+	conf &= ~OMAP3_MCSPI_CHCONF_TRM_MASK;
+
+	writel(conf, &ds->regs->channel[ds->slave.cs].chconf);
+
+	return 0;
+}
+
+void spi_release_bus(struct spi_slave *slave)
+{
+	struct omap3_spi_slave *ds = to_omap3_spi(slave);
+
+	/* Reset the SPI hardware */
+	spi_reset(ds);
+}
+
+int omap3_spi_write(struct spi_slave *slave, unsigned int len, const u8 *txp,
+		    unsigned long flags)
+{
+	struct omap3_spi_slave *ds = to_omap3_spi(slave);
+	int i;
+	int timeout = SPI_WAIT_TIMEOUT;
+	int chconf = readl(&ds->regs->channel[ds->slave.cs].chconf);
+
+	if (flags & SPI_XFER_BEGIN)
+		writel(OMAP3_MCSPI_CHCTRL_EN,
+		       &ds->regs->channel[ds->slave.cs].chctrl);
+
+	chconf &= ~OMAP3_MCSPI_CHCONF_TRM_MASK;
+	chconf |= OMAP3_MCSPI_CHCONF_TRM_TX_ONLY;
+	chconf |= OMAP3_MCSPI_CHCONF_FORCE;
+	writel(chconf, &ds->regs->channel[ds->slave.cs].chconf);
+
+	for (i = 0; i < len; i++) {
+		/* wait till TX register is empty (TXS == 1) */
+		while (!(readl(&ds->regs->channel[ds->slave.cs].chstat) &
+			 OMAP3_MCSPI_CHSTAT_TXS)) {
+			if (--timeout <= 0) {
+				printf("SPI TXS timed out, status=0x%08x\n",
+				       readl(&ds->regs->channel[ds->slave.cs].chstat));
+				return -1;
+			}
+		}
+		/* Write the data */
+		writel(txp[i], &ds->regs->channel[ds->slave.cs].tx);
+	}
+
+	if (flags & SPI_XFER_END) {
+		/* wait to finish of transfer */
+		while (!(readl(&ds->regs->channel[ds->slave.cs].chstat) &
+			 OMAP3_MCSPI_CHSTAT_EOT));
+
+		chconf &= ~OMAP3_MCSPI_CHCONF_FORCE;
+		writel(chconf, &ds->regs->channel[ds->slave.cs].chconf);
+
+		writel(0, &ds->regs->channel[ds->slave.cs].chctrl);
+	}
+	return 0;
+}
+
+int omap3_spi_read(struct spi_slave *slave, unsigned int len, u8 *rxp,
+		   unsigned long flags)
+{
+	struct omap3_spi_slave *ds = to_omap3_spi(slave);
+	int i;
+	int timeout = SPI_WAIT_TIMEOUT;
+	int chconf = readl(&ds->regs->channel[ds->slave.cs].chconf);
+
+	if (flags & SPI_XFER_BEGIN)
+		writel(OMAP3_MCSPI_CHCTRL_EN,
+		       &ds->regs->channel[ds->slave.cs].chctrl);
+
+	chconf &= ~OMAP3_MCSPI_CHCONF_TRM_MASK;
+	chconf |= OMAP3_MCSPI_CHCONF_TRM_RX_ONLY;
+	chconf |= OMAP3_MCSPI_CHCONF_FORCE;
+	writel(chconf, &ds->regs->channel[ds->slave.cs].chconf);
+
+	writel(0, &ds->regs->channel[ds->slave.cs].tx);
+
+	for (i = 0; i < len; i++) {
+		/* Wait till RX register contains data (RXS == 1) */
+		while (!(readl(&ds->regs->channel[ds->slave.cs].chstat) &
+			 OMAP3_MCSPI_CHSTAT_RXS)) {
+			if (--timeout <= 0) {
+				printf("SPI RXS timed out, status=0x%08x\n",
+				       readl(&ds->regs->channel[ds->slave.cs].chstat));
+				return -1;
+			}
+		}
+		/* Read the data */
+		rxp[i] = readl(&ds->regs->channel[ds->slave.cs].rx);
+	}
+
+	if (flags & SPI_XFER_END) {
+		chconf &= ~OMAP3_MCSPI_CHCONF_FORCE;
+		writel(chconf, &ds->regs->channel[ds->slave.cs].chconf);
+
+		writel(0, &ds->regs->channel[ds->slave.cs].chctrl);
+	}
+
+	return 0;
+}
+
+int spi_xfer(struct spi_slave *slave, unsigned int bitlen,
+	     const void *dout, void *din, unsigned long flags)
+{
+	struct omap3_spi_slave *ds = to_omap3_spi(slave);
+	unsigned int	len;
+	const u8	*txp = dout;
+	u8		*rxp = din;
+	int ret = -1;
+
+	if (bitlen % 8)
+		return -1;
+
+	len = bitlen / 8;
+
+	if (bitlen == 0) {	 /* only change CS */
+		int chconf = readl(&ds->regs->channel[ds->slave.cs].chconf);
+
+		if (flags & SPI_XFER_BEGIN) {
+			writel(OMAP3_MCSPI_CHCTRL_EN,
+			       &ds->regs->channel[ds->slave.cs].chctrl);
+			chconf |= OMAP3_MCSPI_CHCONF_FORCE;
+			writel(chconf,
+			       &ds->regs->channel[ds->slave.cs].chconf);
+		}
+		if (flags & SPI_XFER_END) {
+			chconf &= ~OMAP3_MCSPI_CHCONF_FORCE;
+			writel(chconf,
+			       &ds->regs->channel[ds->slave.cs].chconf);
+			writel(0, &ds->regs->channel[ds->slave.cs].chctrl);
+		}
+		ret = 0;
+	} else {
+		if (dout != NULL)
+			ret = omap3_spi_write(slave, len, txp, flags);
+
+		if (din != NULL)
+			ret = omap3_spi_read(slave, len, rxp, flags);
+	}
+	return ret;
+}
+
+int spi_cs_is_valid(unsigned int bus, unsigned int cs)
+{
+	return 1;
+}
+
+void spi_cs_activate(struct spi_slave *slave)
+{
+}
+
+void spi_cs_deactivate(struct spi_slave *slave)
+{
+}