arm: ep9315: Return back Cirrus Logic EDB9315A board support

This patch returns back support for old ep93xx processors family

Signed-off-by: Sergey Kostanbaev <sergey.kostanbaev@gmail.com>
Cc: albert.u.boot@aribaud.net

1 files changed, 274 insertions, 0 deletions

diff --git a/drivers/spi/ep93xx_spi.c b/drivers/spi/ep93xx_spi.c
new file mode 100644
index 0000000..235557e
--- /dev/null
+++ b/drivers/spi/ep93xx_spi.c
@@ -0,0 +1,274 @@
+/*
+ * SPI Driver for EP93xx
+ *
+ * Copyright (C) 2013 Sergey Kostanabev <sergey.kostanbaev <at> fairwaves.ru>
+ *
+ * Inspired form linux kernel driver and atmel uboot driver
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <spi.h>
+#include <malloc.h>
+
+#include <asm/io.h>
+
+#include <asm/arch/ep93xx.h>
+
+
+#define BIT(x)			(1<<(x))
+#define SSPBASE			SPI_BASE
+
+#define SSPCR0			0x0000
+#define SSPCR0_MODE_SHIFT	6
+#define SSPCR0_SCR_SHIFT	8
+#define SSPCR0_SPH		BIT(7)
+#define SSPCR0_SPO		BIT(6)
+#define SSPCR0_FRF_SPI		0
+#define SSPCR0_DSS_8BIT		7
+
+#define SSPCR1			0x0004
+#define SSPCR1_RIE		BIT(0)
+#define SSPCR1_TIE		BIT(1)
+#define SSPCR1_RORIE		BIT(2)
+#define SSPCR1_LBM		BIT(3)
+#define SSPCR1_SSE		BIT(4)
+#define SSPCR1_MS		BIT(5)
+#define SSPCR1_SOD		BIT(6)
+
+#define SSPDR			0x0008
+
+#define SSPSR			0x000c
+#define SSPSR_TFE		BIT(0)
+#define SSPSR_TNF		BIT(1)
+#define SSPSR_RNE		BIT(2)
+#define SSPSR_RFF		BIT(3)
+#define SSPSR_BSY		BIT(4)
+#define SSPCPSR			0x0010
+
+#define SSPIIR			0x0014
+#define SSPIIR_RIS		BIT(0)
+#define SSPIIR_TIS		BIT(1)
+#define SSPIIR_RORIS		BIT(2)
+#define SSPICR			SSPIIR
+
+#define SSPCLOCK		14745600
+#define SSP_MAX_RATE		(SSPCLOCK / 2)
+#define SSP_MIN_RATE		(SSPCLOCK / (254 * 256))
+
+/* timeout in milliseconds */
+#define SPI_TIMEOUT		5
+/* maximum depth of RX/TX FIFO */
+#define SPI_FIFO_SIZE		8
+
+struct ep93xx_spi_slave {
+	struct spi_slave slave;
+
+	unsigned sspcr0;
+	unsigned sspcpsr;
+};
+
+static inline struct ep93xx_spi_slave *to_ep93xx_spi(struct spi_slave *slave)
+{
+	return container_of(slave, struct ep93xx_spi_slave, slave);
+}
+
+void spi_init()
+{
+}
+
+static inline void ep93xx_spi_write_u8(u16 reg, u8 value)
+{
+	writel(value, (unsigned int *)(SSPBASE + reg));
+}
+
+static inline u8 ep93xx_spi_read_u8(u16 reg)
+{
+	return readl((unsigned int *)(SSPBASE + reg));
+}
+
+static inline void ep93xx_spi_write_u16(u16 reg, u16 value)
+{
+	writel(value, (unsigned int *)(SSPBASE + reg));
+}
+
+static inline u16 ep93xx_spi_read_u16(u16 reg)
+{
+	return (u16)readl((unsigned int *)(SSPBASE + reg));
+}
+
+static int ep93xx_spi_init_hw(unsigned int rate, unsigned int mode,
+				struct ep93xx_spi_slave *slave)
+{
+	unsigned cpsr, scr;
+
+	if (rate > SSP_MAX_RATE)
+		rate = SSP_MAX_RATE;
+
+	if (rate < SSP_MIN_RATE)
+		return -1;
+
+	/* Calculate divisors so that we can get speed according the
+	 * following formula:
+	 *	rate = spi_clock_rate / (cpsr * (1 + scr))
+	 *
+	 * cpsr must be even number and starts from 2, scr can be any number
+	 * between 0 and 255.
+	 */
+	for (cpsr = 2; cpsr <= 254; cpsr += 2) {
+		for (scr = 0; scr <= 255; scr++) {
+			if ((SSPCLOCK / (cpsr * (scr + 1))) <= rate) {
+				/* Set CHPA and CPOL, SPI format and 8bit */
+				unsigned sspcr0 = (scr << SSPCR0_SCR_SHIFT) |
+					SSPCR0_FRF_SPI | SSPCR0_DSS_8BIT;
+				if (mode & SPI_CPHA)
+					sspcr0 |= SSPCR0_SPH;
+				if (mode & SPI_CPOL)
+					sspcr0 |= SSPCR0_SPO;
+
+				slave->sspcr0 = sspcr0;
+				slave->sspcpsr = cpsr;
+				return 0;
+			}
+		}
+	}
+
+	return -1;
+}
+
+void spi_set_speed(struct spi_slave *slave, unsigned int hz)
+{
+	struct ep93xx_spi_slave *as = to_ep93xx_spi(slave);
+
+	unsigned int mode = 0;
+	if (as->sspcr0 & SSPCR0_SPH)
+		mode |= SPI_CPHA;
+	if (as->sspcr0 & SSPCR0_SPO)
+		mode |= SPI_CPOL;
+
+	ep93xx_spi_init_hw(hz, mode, as);
+}
+
+struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
+			unsigned int max_hz, unsigned int mode)
+{
+	struct ep93xx_spi_slave	*as;
+
+	if (!spi_cs_is_valid(bus, cs))
+		return NULL;
+
+	as = spi_alloc_slave(struct ep93xx_spi_slave, bus, cs);
+	if (!as)
+		return NULL;
+
+	if (ep93xx_spi_init_hw(max_hz, mode, as)) {
+		free(as);
+		return NULL;
+	}
+
+	return &as->slave;
+}
+
+void spi_free_slave(struct spi_slave *slave)
+{
+	struct ep93xx_spi_slave *as = to_ep93xx_spi(slave);
+
+	free(as);
+}
+
+int spi_claim_bus(struct spi_slave *slave)
+{
+	struct ep93xx_spi_slave *as = to_ep93xx_spi(slave);
+
+	/* Enable the SPI hardware */
+	ep93xx_spi_write_u8(SSPCR1, SSPCR1_SSE);
+
+
+	ep93xx_spi_write_u8(SSPCPSR, as->sspcpsr);
+	ep93xx_spi_write_u16(SSPCR0, as->sspcr0);
+
+	debug("Select CS:%d SSPCPSR=%02x SSPCR0=%04x\n",
+	      slave->cs, as->sspcpsr, as->sspcr0);
+	return 0;
+}
+
+void spi_release_bus(struct spi_slave *slave)
+{
+	/* Disable the SPI hardware */
+	ep93xx_spi_write_u8(SSPCR1, 0);
+}
+
+int spi_xfer(struct spi_slave *slave, unsigned int bitlen,
+		const void *dout, void *din, unsigned long flags)
+{
+	unsigned int	len_tx;
+	unsigned int	len_rx;
+	unsigned int	len;
+	u32		status;
+	const u8	*txp = dout;
+	u8		*rxp = din;
+	u8		value;
+
+	debug("spi_xfer: slave %u:%u dout %p din %p bitlen %u\n",
+	      slave->bus, slave->cs, (uint *)dout, (uint *)din, bitlen);
+
+
+	if (bitlen == 0)
+		/* Finish any previously submitted transfers */
+		goto out;
+
+	if (bitlen % 8) {
+		/* Errors always terminate an ongoing transfer */
+		flags |= SPI_XFER_END;
+		goto out;
+	}
+
+	len = bitlen / 8;
+
+
+	if (flags & SPI_XFER_BEGIN) {
+		/* Empty RX FIFO */
+		while ((ep93xx_spi_read_u8(SSPSR) & SSPSR_RNE))
+			ep93xx_spi_read_u8(SSPDR);
+
+		spi_cs_activate(slave);
+	}
+
+	for (len_tx = 0, len_rx = 0; len_rx < len; ) {
+		status = ep93xx_spi_read_u8(SSPSR);
+
+		if ((len_tx < len) && (status & SSPSR_TNF)) {
+			if (txp)
+				value = *txp++;
+			else
+				value = 0xff;
+
+			ep93xx_spi_write_u8(SSPDR, value);
+			len_tx++;
+		}
+
+		if (status & SSPSR_RNE) {
+			value = ep93xx_spi_read_u8(SSPDR);
+
+			if (rxp)
+				*rxp++ = value;
+			len_rx++;
+		}
+	}
+
+out:
+	if (flags & SPI_XFER_END) {
+		/*
+		 * Wait until the transfer is completely done before
+		 * we deactivate CS.
+		 */
+		do {
+			status = ep93xx_spi_read_u8(SSPSR);
+		} while (status & SSPSR_BSY);
+
+		spi_cs_deactivate(slave);
+	}
+
+	return 0;
+}