SPI: Add SPI driver support for Marvell Armada100

This patch provides support for SPI emulated over SSP for Marvell
Armada100 SOC.

Signed-off-by: Ajay Bhargav <ajay.bhargav@einfochips.com>

1 files changed, 228 insertions, 0 deletions

diff --git a/drivers/spi/armada100_spi.c b/drivers/spi/armada100_spi.c
new file mode 100644
index 0000000..7384c9c
--- /dev/null
+++ b/drivers/spi/armada100_spi.c
@@ -0,0 +1,228 @@
+/*
+ * (C) Copyright 2011
+ * eInfochips Ltd. <www.einfochips.com>
+ * Written-by: Ajay Bhargav <ajay.bhargav@einfochips.com>
+ *
+ * (C) Copyright 2009
+ * Marvell Semiconductor <www.marvell.com>
+ * Based on SSP driver
+ * Written-by: Lei Wen <leiwen@marvell.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., 51 Franklin Street, Fifth Floor, Boston,
+ * MA 02110-1301 USA
+ */
+
+
+#include <common.h>
+#include <malloc.h>
+#include <spi.h>
+
+#include <asm/io.h>
+#include <asm/arch/spi.h>
+#include <asm/gpio.h>
+
+#define to_armd_spi_slave(s)	container_of(s, struct armd_spi_slave, slave)
+
+struct armd_spi_slave {
+	struct spi_slave slave;
+	struct ssp_reg *spi_reg;
+	u32 cr0, cr1;
+	u32 int_cr1;
+	u32 clear_sr;
+	const void *tx;
+	void *rx;
+	int gpio_cs_inverted;
+};
+
+static int spi_armd_write(struct armd_spi_slave *pss)
+{
+	int wait_timeout = SSP_FLUSH_NUM;
+	while (--wait_timeout && !(readl(&pss->spi_reg->sssr) & SSSR_TNF))
+		;
+	if (!wait_timeout) {
+		debug("%s: timeout error\n", __func__);
+		return -1;
+	}
+
+	if (pss->tx != NULL) {
+		writel(*(u8 *)pss->tx, &pss->spi_reg->ssdr);
+		++pss->tx;
+	} else {
+		writel(0, &pss->spi_reg->ssdr);
+	}
+	return 0;
+}
+
+static int spi_armd_read(struct armd_spi_slave *pss)
+{
+	int wait_timeout = SSP_FLUSH_NUM;
+	while (--wait_timeout && !(readl(&pss->spi_reg->sssr) & SSSR_RNE))
+		;
+	if (!wait_timeout) {
+		debug("%s: timeout error\n", __func__);
+		return -1;
+	}
+
+	if (pss->rx != NULL) {
+		*(u8 *)pss->rx = readl(&pss->spi_reg->ssdr);
+		++pss->rx;
+	} else {
+		readl(&pss->spi_reg->ssdr);
+	}
+	return 0;
+}
+
+static int spi_armd_flush(struct armd_spi_slave *pss)
+{
+	unsigned long limit = SSP_FLUSH_NUM;
+
+	do {
+		while (readl(&pss->spi_reg->sssr) & SSSR_RNE)
+			readl(&pss->spi_reg->ssdr);
+	} while ((readl(&pss->spi_reg->sssr) & SSSR_BSY) && limit--);
+
+	writel(SSSR_ROR, &pss->spi_reg->sssr);
+
+	return limit;
+}
+
+void spi_cs_activate(struct spi_slave *slave)
+{
+	struct armd_spi_slave *pss = to_armd_spi_slave(slave);
+
+	gpio_set_value(slave->cs, pss->gpio_cs_inverted);
+}
+
+void spi_cs_deactivate(struct spi_slave *slave)
+{
+	struct armd_spi_slave *pss = to_armd_spi_slave(slave);
+
+	gpio_set_value(slave->cs, !pss->gpio_cs_inverted);
+}
+
+struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
+		unsigned int max_hz, unsigned int mode)
+{
+	struct armd_spi_slave *pss;
+
+	pss = malloc(sizeof(*pss));
+	if (!pss)
+		return NULL;
+
+	pss->slave.bus = bus;
+	pss->slave.cs = cs;
+	pss->spi_reg = (struct ssp_reg *)SSP_REG_BASE(CONFIG_SYS_SSP_PORT);
+
+	pss->cr0 = SSCR0_MOTO | SSCR0_DATASIZE(DEFAULT_WORD_LEN) | SSCR0_SSE;
+
+	pss->cr1 = (SSCR1_RXTRESH(RX_THRESH_DEF) & SSCR1_RFT) |
+		(SSCR1_TXTRESH(TX_THRESH_DEF) & SSCR1_TFT);
+	pss->cr1 &= ~(SSCR1_SPO | SSCR1_SPH);
+	pss->cr1 |= (((mode & SPI_CPHA) != 0) ? SSCR1_SPH : 0)
+		| (((mode & SPI_CPOL) != 0) ? SSCR1_SPO : 0);
+
+	pss->int_cr1 = SSCR1_TIE | SSCR1_RIE | SSCR1_TINTE;
+	pss->clear_sr = SSSR_ROR | SSSR_TINT;
+
+	pss->gpio_cs_inverted = mode & SPI_CS_HIGH;
+	gpio_set_value(cs, !pss->gpio_cs_inverted);
+
+	return &pss->slave;
+}
+
+void spi_free_slave(struct spi_slave *slave)
+{
+	struct armd_spi_slave *pss = to_armd_spi_slave(slave);
+
+	free(pss);
+}
+
+int spi_claim_bus(struct spi_slave *slave)
+{
+	struct armd_spi_slave *pss = to_armd_spi_slave(slave);
+
+	debug("%s: bus:%i cs:%i\n", __func__, slave->bus, slave->cs);
+	if (spi_armd_flush(pss) == 0)
+		return -1;
+
+	return 0;
+}
+
+void spi_release_bus(struct spi_slave *slave)
+{
+}
+
+int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *dout,
+		void *din, unsigned long flags)
+{
+	struct armd_spi_slave *pss = to_armd_spi_slave(slave);
+	uint bytes = bitlen / 8;
+	unsigned long limit;
+	int ret = 0;
+
+	if (bitlen == 0)
+		goto done;
+
+	/* we can only do 8 bit transfers */
+	if (bitlen % 8) {
+		flags |= SPI_XFER_END;
+		goto done;
+	}
+
+	if (dout)
+		pss->tx = dout;
+	else
+		pss->tx = NULL;
+
+	if (din)
+		pss->rx = din;
+	else
+		pss->rx = NULL;
+
+	if (flags & SPI_XFER_BEGIN) {
+		spi_cs_activate(slave);
+		writel(pss->cr1 | pss->int_cr1, &pss->spi_reg->sscr1);
+		writel(TIMEOUT_DEF, &pss->spi_reg->ssto);
+		writel(pss->cr0, &pss->spi_reg->sscr0);
+	}
+
+	while (bytes--) {
+		limit = SSP_FLUSH_NUM;
+		ret = spi_armd_write(pss);
+		if (ret)
+			break;
+
+		while ((readl(&pss->spi_reg->sssr) & SSSR_BSY) && limit--)
+			udelay(1);
+
+		ret = spi_armd_read(pss);
+		if (ret)
+			break;
+	}
+
+ done:
+	if (flags & SPI_XFER_END) {
+		/* Stop SSP */
+		writel(pss->clear_sr, &pss->spi_reg->sssr);
+		clrbits_le32(&pss->spi_reg->sscr1, pss->int_cr1);
+		writel(0, &pss->spi_reg->ssto);
+		spi_cs_deactivate(slave);
+	}
+
+	return ret;
+}