spi: add new driver for OpenCores tiny_spi

This patch adds support for OpenCores tiny_spi.

http://opencores.org/project,tiny_spi

Signed-off-by: Thomas Chou <thomas@wytron.com.tw>

1 files changed, 248 insertions, 0 deletions

diff --git a/drivers/spi/oc_tiny_spi.c b/drivers/spi/oc_tiny_spi.c
new file mode 100644
index 0000000..fc01fb8
--- /dev/null
+++ b/drivers/spi/oc_tiny_spi.c
@@ -0,0 +1,248 @@
+/*
+ * Opencore tiny_spi driver
+ *
+ * http://opencores.org/project,tiny_spi
+ *
+ * based on bfin_spi.c
+ * Copyright (c) 2005-2008 Analog Devices Inc.
+ * Copyright (C) 2010 Thomas Chou <thomas@wytron.com.tw>
+ *
+ * Licensed under the GPL-2 or later.
+ */
+
+#include <common.h>
+#include <asm/io.h>
+#include <malloc.h>
+#include <spi.h>
+#include <asm/gpio.h>
+
+#define TINY_SPI_STATUS_TXE 0x1
+#define TINY_SPI_STATUS_TXR 0x2
+
+struct tiny_spi_regs {
+	unsigned rxdata;	/* Rx data reg */
+	unsigned txdata;	/* Tx data reg */
+	unsigned status;	/* Status reg */
+	unsigned control;	/* Control reg */
+	unsigned baud;		/* Baud reg */
+};
+
+struct tiny_spi_host {
+	uint base;
+	uint freq;
+	uint baudwidth;
+};
+static const struct tiny_spi_host tiny_spi_host_list[] =
+	CONFIG_SYS_TINY_SPI_LIST;
+
+struct tiny_spi_slave {
+	struct spi_slave slave;
+	const struct tiny_spi_host *host;
+	uint mode;
+	uint baud;
+	uint flg;
+};
+#define to_tiny_spi_slave(s) container_of(s, struct tiny_spi_slave, slave)
+
+int spi_cs_is_valid(unsigned int bus, unsigned int cs)
+{
+	return bus < ARRAY_SIZE(tiny_spi_host_list) && gpio_is_valid(cs);
+}
+
+void spi_cs_activate(struct spi_slave *slave)
+{
+	struct tiny_spi_slave *tiny_spi = to_tiny_spi_slave(slave);
+	unsigned int cs = slave->cs;
+
+	gpio_set_value(cs, tiny_spi->flg);
+	debug("%s: SPI_CS_GPIO:%x\n", __func__, gpio_get_value(cs));
+}
+
+void spi_cs_deactivate(struct spi_slave *slave)
+{
+	struct tiny_spi_slave *tiny_spi = to_tiny_spi_slave(slave);
+	unsigned int cs = slave->cs;
+
+	gpio_set_value(cs, !tiny_spi->flg);
+	debug("%s: SPI_CS_GPIO:%x\n", __func__, gpio_get_value(cs));
+}
+
+void spi_set_speed(struct spi_slave *slave, uint hz)
+{
+	struct tiny_spi_slave *tiny_spi = to_tiny_spi_slave(slave);
+	const struct tiny_spi_host *host = tiny_spi->host;
+
+	tiny_spi->baud = min(DIV_ROUND_UP(host->freq, hz * 2),
+			     (1 << host->baudwidth)) - 1;
+	debug("%s: speed %u actual %u\n", __func__, hz,
+	      host->freq / ((tiny_spi->baud + 1) * 2));
+}
+
+void spi_init(void)
+{
+}
+
+struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
+				  unsigned int hz, unsigned int mode)
+{
+	struct tiny_spi_slave *tiny_spi;
+
+	if (!spi_cs_is_valid(bus, cs) || gpio_request(cs, "tiny_spi"))
+		return NULL;
+
+	tiny_spi = malloc(sizeof(*tiny_spi));
+	if (!tiny_spi)
+		return NULL;
+	memset(tiny_spi, 0, sizeof(*tiny_spi));
+
+	tiny_spi->slave.bus = bus;
+	tiny_spi->slave.cs = cs;
+	tiny_spi->host = &tiny_spi_host_list[bus];
+	tiny_spi->mode = mode & (SPI_CPOL | SPI_CPHA);
+	tiny_spi->flg = mode & SPI_CS_HIGH ? 1 : 0;
+	spi_set_speed(&tiny_spi->slave, hz);
+
+	debug("%s: bus:%i cs:%i base:%lx\n", __func__,
+		bus, cs, tiny_spi->host->base);
+	return &tiny_spi->slave;
+}
+
+void spi_free_slave(struct spi_slave *slave)
+{
+	struct tiny_spi_slave *tiny_spi = to_tiny_spi_slave(slave);
+
+	gpio_free(slave->cs);
+	free(tiny_spi);
+}
+
+int spi_claim_bus(struct spi_slave *slave)
+{
+	struct tiny_spi_slave *tiny_spi = to_tiny_spi_slave(slave);
+	struct tiny_spi_regs *regs = (void *)tiny_spi->host->base;
+
+	debug("%s: bus:%i cs:%i\n", __func__, slave->bus, slave->cs);
+	gpio_direction_output(slave->cs, !tiny_spi->flg);
+	writel(tiny_spi->mode, &regs->control);
+	writel(tiny_spi->baud, &regs->baud);
+	return 0;
+}
+
+void spi_release_bus(struct spi_slave *slave)
+{
+	debug("%s: bus:%i cs:%i\n", __func__, slave->bus, slave->cs);
+}
+
+#ifndef CONFIG_TINY_SPI_IDLE_VAL
+# define CONFIG_TINY_SPI_IDLE_VAL 0xff
+#endif
+
+int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *dout,
+	     void *din, unsigned long flags)
+{
+	struct tiny_spi_slave *tiny_spi = to_tiny_spi_slave(slave);
+	struct tiny_spi_regs *regs = (void *)tiny_spi->host->base;
+	const u8 *txp = dout;
+	u8 *rxp = din;
+	uint bytes = bitlen / 8;
+	uint i;
+
+	debug("%s: bus:%i cs:%i bitlen:%i bytes:%i flags:%lx\n", __func__,
+		slave->bus, slave->cs, bitlen, bytes, flags);
+	if (bitlen == 0)
+		goto done;
+
+	/* assume to do 8 bits transfers */
+	if (bitlen % 8) {
+		flags |= SPI_XFER_END;
+		goto done;
+	}
+
+	if (flags & SPI_XFER_BEGIN)
+		spi_cs_activate(slave);
+
+	/* we need to tighten the transfer loop */
+	if (txp && rxp) {
+		writeb(*txp++, &regs->txdata);
+		if (bytes > 1) {
+			writeb(*txp++, &regs->txdata);
+			for (i = 2; i < bytes; i++) {
+				u8 rx, tx = *txp++;
+				while (!(readb(&regs->status) &
+					 TINY_SPI_STATUS_TXR))
+					;
+				rx = readb(&regs->txdata);
+				writeb(tx, &regs->txdata);
+				*rxp++ = rx;
+			}
+			while (!(readb(&regs->status) &
+				 TINY_SPI_STATUS_TXR))
+				;
+			*rxp++ = readb(&regs->txdata);
+		}
+		while (!(readb(&regs->status) &
+			 TINY_SPI_STATUS_TXE))
+			;
+		*rxp++ = readb(&regs->rxdata);
+	} else if (rxp) {
+		writeb(CONFIG_TINY_SPI_IDLE_VAL, &regs->txdata);
+		if (bytes > 1) {
+			writeb(CONFIG_TINY_SPI_IDLE_VAL,
+			       &regs->txdata);
+			for (i = 2; i < bytes; i++) {
+				u8 rx;
+				while (!(readb(&regs->status) &
+					 TINY_SPI_STATUS_TXR))
+					;
+				rx = readb(&regs->txdata);
+				writeb(CONFIG_TINY_SPI_IDLE_VAL,
+				       &regs->txdata);
+				*rxp++ = rx;
+			}
+			while (!(readb(&regs->status) &
+				 TINY_SPI_STATUS_TXR))
+				;
+			*rxp++ = readb(&regs->txdata);
+		}
+		while (!(readb(&regs->status) &
+			 TINY_SPI_STATUS_TXE))
+			;
+		*rxp++ = readb(&regs->rxdata);
+	} else if (txp) {
+		writeb(*txp++, &regs->txdata);
+		if (bytes > 1) {
+			writeb(*txp++, &regs->txdata);
+			for (i = 2; i < bytes; i++) {
+				u8 tx = *txp++;
+				while (!(readb(&regs->status) &
+					 TINY_SPI_STATUS_TXR))
+					;
+				writeb(tx, &regs->txdata);
+			}
+		}
+		while (!(readb(&regs->status) &
+			 TINY_SPI_STATUS_TXE))
+			;
+	} else {
+		writeb(CONFIG_TINY_SPI_IDLE_VAL, &regs->txdata);
+		if (bytes > 1) {
+			writeb(CONFIG_TINY_SPI_IDLE_VAL,
+			       &regs->txdata);
+			for (i = 2; i < bytes; i++) {
+				while (!(readb(&regs->status) &
+					 TINY_SPI_STATUS_TXR))
+					;
+				writeb(CONFIG_TINY_SPI_IDLE_VAL,
+				       &regs->txdata);
+			}
+		}
+		while (!(readb(&regs->status) &
+			 TINY_SPI_STATUS_TXE))
+			;
+	}
+
+ done:
+	if (flags & SPI_XFER_END)
+		spi_cs_deactivate(slave);
+
+	return 0;
+}