New i.MX31 SPI driver

This is an SPI driver for i.MX and MXC based SoCs from Freescale. So far
only implemented and tested on i.MX31, can with a modified register layout
and definitions be used for i.MX27, I think, MXC CPUs have similar SPI
controllers too.

Signed-off-by: Guennadi Liakhovetski <lg@denx.de>

README

@@ -1414,6 +1414,11 @@ The following options need to be configured:
 		Currently supported on some MPC8xxx processors.  For an
 		example, see include/configs/mpc8349emds.h.
 
+		CONFIG_MXC_SPI
+
+		Enables the driver for the SPI controllers on i.MX and MXC
+		SoCs. Currently only i.MX31 is supported.
+
 - FPGA Support: CONFIG_FPGA
 
 		Enables FPGA subsystem.

drivers/spi/Makefile

@@ -26,6 +26,7 @@ include $(TOPDIR)/config.mk
 LIB	:= $(obj)libspi.a
 
 COBJS-y += mpc8xxx_spi.o
+COBJS-$(CONFIG_MXC_SPI) += mxc_spi.o
 
 COBJS	:= $(COBJS-y)
 SRCS	:= $(COBJS:.o=.c)

drivers/spi/mxc_spi.c

@@ -0,0 +1,166 @@
+/*
+ * Copyright (C) 2008, Guennadi Liakhovetski <lg@denx.de>
+ *
+ * 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 <asm/io.h>
+
+#ifdef CONFIG_MX27
+/* i.MX27 has a completely wrong register layout and register definitions in the
+ * datasheet, the correct one is in the Freescale's Linux driver */
+
+#error "i.MX27 CSPI not supported due to drastic differences in register definisions" \
+"See linux mxc_spi driver from Freescale for details."
+
+#else
+
+#define MXC_CSPIRXDATA		0x00
+#define MXC_CSPITXDATA		0x04
+#define MXC_CSPICTRL		0x08
+#define MXC_CSPIINT		0x0C
+#define MXC_CSPIDMA		0x10
+#define MXC_CSPISTAT		0x14
+#define MXC_CSPIPERIOD		0x18
+#define MXC_CSPITEST		0x1C
+#define MXC_CSPIRESET		0x00
+
+#define MXC_CSPICTRL_EN		(1 << 0)
+#define MXC_CSPICTRL_MODE	(1 << 1)
+#define MXC_CSPICTRL_XCH	(1 << 2)
+#define MXC_CSPICTRL_SMC	(1 << 3)
+#define MXC_CSPICTRL_POL	(1 << 4)
+#define MXC_CSPICTRL_PHA	(1 << 5)
+#define MXC_CSPICTRL_SSCTL	(1 << 6)
+#define MXC_CSPICTRL_SSPOL 	(1 << 7)
+#define MXC_CSPICTRL_CHIPSELECT(x)	(((x) & 0x3) << 24)
+#define MXC_CSPICTRL_BITCOUNT(x)	(((x) & 0x1f) << 8)
+#define MXC_CSPICTRL_DATARATE(x)	(((x) & 0x7) << 16)
+
+#define MXC_CSPIPERIOD_32KHZ	(1 << 15)
+
+static unsigned long spi_bases[] = {
+	0x43fa4000,
+	0x50010000,
+	0x53f84000,
+};
+
+static unsigned long spi_base;
+
+#endif
+
+spi_chipsel_type spi_chipsel[] = {
+	(spi_chipsel_type)0,
+	(spi_chipsel_type)1,
+	(spi_chipsel_type)2,
+	(spi_chipsel_type)3,
+};
+int spi_chipsel_cnt = sizeof(spi_chipsel) / sizeof(spi_chipsel[0]);
+
+static inline u32 reg_read(unsigned long addr)
+{
+	return *(volatile unsigned long*)addr;
+}
+
+static inline void reg_write(unsigned long addr, u32 val)
+{
+	*(volatile unsigned long*)addr = val;
+}
+
+static u32 spi_xchg_single(u32 data, int bitlen)
+{
+
+	unsigned int cfg_reg = reg_read(spi_base + MXC_CSPICTRL);
+
+	if (MXC_CSPICTRL_BITCOUNT(bitlen - 1) != (cfg_reg & MXC_CSPICTRL_BITCOUNT(31))) {
+		cfg_reg = (cfg_reg & ~MXC_CSPICTRL_BITCOUNT(31)) |
+			MXC_CSPICTRL_BITCOUNT(bitlen - 1);
+		reg_write(spi_base + MXC_CSPICTRL, cfg_reg);
+	}
+
+	reg_write(spi_base + MXC_CSPITXDATA, data);
+
+	cfg_reg |= MXC_CSPICTRL_XCH;
+
+	reg_write(spi_base + MXC_CSPICTRL, cfg_reg);
+
+	while (reg_read(spi_base + MXC_CSPICTRL) & MXC_CSPICTRL_XCH)
+		;
+
+	return reg_read(spi_base + MXC_CSPIRXDATA);
+}
+
+int spi_xfer(spi_chipsel_type chipsel, int bitlen, uchar *dout, uchar *din)
+{
+	int n_blks = (bitlen + 31) / 32;
+	u32 *out_l, *in_l;
+	int i;
+
+	if ((int)dout & 3 || (int)din & 3) {
+		printf("Error: unaligned buffers in: %p, out: %p\n", din, dout);
+		return 1;
+	}
+
+	if (!spi_base)
+		spi_select(CONFIG_MXC_SPI_IFACE, (int)chipsel, SPI_MODE_2 | SPI_CS_HIGH);
+
+	for (i = 0, in_l = (u32 *)din, out_l = (u32 *)dout;
+	     i < n_blks;
+	     i++, in_l++, out_l++, bitlen -= 32)
+		*in_l = spi_xchg_single(*out_l, bitlen);
+
+	return 0;
+}
+
+void spi_init(void)
+{
+}
+
+int spi_select(unsigned int bus, unsigned int dev, unsigned long mode)
+{
+	unsigned int ctrl_reg;
+
+	if (bus >= sizeof(spi_bases) / sizeof(spi_bases[0]) ||
+	    dev > 3)
+		return 1;
+
+	spi_base = spi_bases[bus];
+
+	ctrl_reg = MXC_CSPICTRL_CHIPSELECT(dev) |
+		MXC_CSPICTRL_BITCOUNT(31) |
+		MXC_CSPICTRL_DATARATE(7) | /* FIXME: calculate data rate */
+		MXC_CSPICTRL_EN |
+		MXC_CSPICTRL_MODE;
+
+	if (mode & SPI_CPHA)
+		ctrl_reg |= MXC_CSPICTRL_PHA;
+	if (!(mode & SPI_CPOL))
+		ctrl_reg |= MXC_CSPICTRL_POL;
+	if (mode & SPI_CS_HIGH)
+		ctrl_reg |= MXC_CSPICTRL_SSPOL;
+
+	reg_write(spi_base + MXC_CSPIRESET, 1);
+	udelay(1);
+	reg_write(spi_base + MXC_CSPICTRL, ctrl_reg);
+	reg_write(spi_base + MXC_CSPIPERIOD,
+		  MXC_CSPIPERIOD_32KHZ);
+	reg_write(spi_base + MXC_CSPIINT, 0);
+
+	return 0;
+}

include/asm-arm/arch-mx31/mx31-regs.h

@@ -37,6 +37,9 @@
 #define CCM_UPCTL	(CCM_BASE + 0x10)
 #define CCM_SPCTL	(CCM_BASE + 0x18)
 #define CCM_COSR	(CCM_BASE + 0x1C)
+#define CCM_CGR0	(CCM_BASE + 0x20)
+#define CCM_CGR1	(CCM_BASE + 0x24)
+#define CCM_CGR2	(CCM_BASE + 0x28)
 
 #define CCMR_MDS	(1 << 7)
 #define CCMR_SBYCS	(1 << 4)
@@ -118,7 +121,9 @@
 #define MUX_CTL_RXD1		0x82
 #define MUX_CTL_TXD1		0x83
 #define MUX_CTL_CSPI2_MISO	0x84
-/* 0x85 .. 0x8a */
+#define MUX_CTL_CSPI2_SS0	0x85
+#define MUX_CTL_CSPI2_SS1	0x86
+#define MUX_CTL_CSPI2_SS2	0x87
 #define MUX_CTL_CSPI2_MOSI	0x8b
 
 /* The modes a specific pin can be in

include/spi.h

@@ -24,6 +24,18 @@
 #ifndef _SPI_H_
 #define _SPI_H_
 
+/* SPI mode flags */
+#define	SPI_CPHA	0x01			/* clock phase */
+#define	SPI_CPOL	0x02			/* clock polarity */
+#define	SPI_MODE_0	(0|0)			/* (original MicroWire) */
+#define	SPI_MODE_1	(0|SPI_CPHA)
+#define	SPI_MODE_2	(SPI_CPOL|0)
+#define	SPI_MODE_3	(SPI_CPOL|SPI_CPHA)
+#define	SPI_CS_HIGH	0x04			/* chipselect active high? */
+#define	SPI_LSB_FIRST	0x08			/* per-word bits-on-wire */
+#define	SPI_3WIRE	0x10			/* SI/SO signals shared */
+#define	SPI_LOOP	0x20			/* loopback mode */
+
 /*
  * The function call pointer type used to drive the chip select.
  */
@@ -68,6 +80,8 @@ void spi_init(void);
  *
  *   Returns: 0 on success, not 0 on failure
  */
-int  spi_xfer(spi_chipsel_type chipsel, int bitlen, uchar *dout, uchar *din);
+int spi_xfer(spi_chipsel_type chipsel, int bitlen, uchar *dout, uchar *din);
+
+int spi_select(unsigned int bus, unsigned int dev, unsigned long mode);
 
 #endif	/* _SPI_H_ */