add an i2c driver for mx31

This patch adds an i2c driver for Freescale i.MX processors

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Guennadi Liakhovetski <lg@denx.de>

drivers/i2c/Makefile

@@ -29,6 +29,7 @@ COBJS-y += fsl_i2c.o
 COBJS-y += omap1510_i2c.o
 COBJS-y += omap24xx_i2c.o
 COBJS-y += tsi108_i2c.o
+COBJS-y += mxc_i2c.o
 
 COBJS	:= $(COBJS-y)
 SRCS 	:= $(COBJS:.o=.c)

drivers/i2c/mxc_i2c.c

+/*
+ * i2c driver for Freescale mx31
+ *
+ * (c) 2007 Pengutronix, Sascha Hauer <s.hauer@pengutronix.de>
+ *
+ * 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>
+
+#if defined(CONFIG_HARD_I2C) && defined(CONFIG_I2C_MXC)
+
+#include <asm/arch/mx31.h>
+#include <asm/arch/mx31-regs.h>
+
+#define IADR	0x00
+#define IFDR	0x04
+#define I2CR	0x08
+#define I2SR	0x0c
+#define I2DR	0x10
+
+#define I2CR_IEN	(1 << 7)
+#define I2CR_IIEN	(1 << 6)
+#define I2CR_MSTA	(1 << 5)
+#define I2CR_MTX	(1 << 4)
+#define I2CR_TX_NO_AK	(1 << 3)
+#define I2CR_RSTA	(1 << 2)
+
+#define I2SR_ICF	(1 << 7)
+#define I2SR_IBB	(1 << 5)
+#define I2SR_IIF	(1 << 1)
+#define I2SR_RX_NO_AK	(1 << 0)
+
+#ifdef CFG_I2C_MX31_PORT1
+#define I2C_BASE	0x43f80000
+#elif defined(CFG_I2C_MX31_PORT2)
+#define I2C_BASE	0x43f98000
+#elif defined(CFG_I2C_MX31_PORT3)
+#define I2C_BASE	0x43f84000
+#else
+#error "define CFG_I2C_MX31_PORTx to use the mx31 I2C driver"
+#endif
+
+#ifdef DEBUG
+#define DPRINTF(args...)  printf(args)
+#else
+#define DPRINTF(args...)
+#endif
+
+static u16 div[] = { 30, 32, 36, 42, 48, 52, 60, 72, 80, 88, 104, 128, 144,
+			160, 192, 240, 288, 320, 384, 480, 576, 640, 768, 960,
+			1152, 1280, 1536, 1920, 2304, 2560, 3072, 3840};
+
+void i2c_init(int speed, int unused)
+{
+	int freq = mx31_get_ipg_clk();
+	int i;
+
+	for (i = 0; i < 0x1f; i++)
+		if (freq / div[i] <= speed)
+			break;
+
+	DPRINTF("%s: speed: %d\n", __FUNCTION__, speed);
+
+	__REG16(I2C_BASE + I2CR) = 0; /* Reset module */
+	__REG16(I2C_BASE + IFDR) = i;
+	__REG16(I2C_BASE + I2CR) = I2CR_IEN;
+	__REG16(I2C_BASE + I2SR) = 0;
+}
+
+static int wait_busy(void)
+{
+	int timeout = 10000;
+
+	while (!(__REG16(I2C_BASE + I2SR) & I2SR_IIF) && --timeout)
+		udelay(1);
+	__REG16(I2C_BASE + I2SR) = 0; /* clear interrupt */
+
+	return timeout;
+}
+
+static int tx_byte(u8 byte)
+{
+	__REG16(I2C_BASE + I2DR) = byte;
+
+	if (!wait_busy() || __REG16(I2C_BASE + I2SR) & I2SR_RX_NO_AK)
+		return -1;
+	return 0;
+}
+
+static int rx_byte(void)
+{
+	if (!wait_busy())
+		return -1;
+
+	return __REG16(I2C_BASE + I2DR);
+}
+
+int i2c_probe(uchar chip)
+{
+	int ret;
+
+	__REG16(I2C_BASE + I2CR) = 0; /* Reset module */
+	__REG16(I2C_BASE + I2CR) = I2CR_IEN;
+
+	__REG16(I2C_BASE + I2CR) = I2CR_IEN |  I2CR_MSTA | I2CR_MTX;
+	ret = tx_byte(chip << 1);
+	__REG16(I2C_BASE + I2CR) = I2CR_IEN | I2CR_MTX;
+
+	return ret;
+}
+
+static int i2c_addr(uchar chip, uint addr, int alen)
+{
+	__REG16(I2C_BASE + I2SR) = 0; /* clear interrupt */
+	__REG16(I2C_BASE + I2CR) = I2CR_IEN |  I2CR_MSTA | I2CR_MTX;
+
+	if (tx_byte(chip << 1))
+		return -1;
+
+	while (alen--)
+		if (tx_byte((addr >> (alen * 8)) & 0xff))
+			return -1;
+	return 0;
+}
+
+int i2c_read(uchar chip, uint addr, int alen, uchar *buf, int len)
+{
+	int timeout = 10000;
+	int ret;
+
+	DPRINTF("%s chip: 0x%02x addr: 0x%04x alen: %d len: +%d\n", \
+				__FUNCTION__, chip, addr, alen, len);
+
+	if (i2c_addr(chip, addr, alen)) {
+		printf("i2c_addr failed\n");
+		return -1;
+	}
+
+	__REG16(I2C_BASE + I2CR) = I2CR_IEN |  I2CR_MSTA |	\
+					I2CR_MTX | I2CR_RSTA;
+
+	if (tx_byte(chip << 1 | 1))
+		return -1;
+
+	__REG16(I2C_BASE + I2CR) = I2CR_IEN |  I2CR_MSTA | ((len == 1)	\
+							? I2CR_TX_NO_AK : 0);
+
+	ret = __REG16(I2C_BASE + I2DR);
+
+	while (len--) {
+		if ((ret = rx_byte()) < 0)
+			return -1;
+		*buf++ = ret;
+		if (len <= 1)
+			__REG16(I2C_BASE + I2CR) = I2CR_IEN |	\
+					I2CR_MSTA | I2CR_TX_NO_AK;
+	}
+
+	wait_busy();
+
+	__REG16(I2C_BASE + I2CR) = I2CR_IEN;
+
+	while (__REG16(I2C_BASE + I2SR) & I2SR_IBB && --timeout)
+		udelay(1);
+
+	return 0;
+}
+
+int i2c_write(uchar chip, uint addr, int alen, uchar *buf, int len)
+{
+	int timeout = 10000;
+	DPRINTF("%s chip: 0x%02x addr: 0x%04x alen: %d len: %d\n",	\
+					__FUNCTION__, chip, addr, alen, len);
+
+	if (i2c_addr(chip, addr, alen))
+		return -1;
+
+	while (len--)
+		if (tx_byte(*buf++))
+			return -1;
+
+	__REG16(I2C_BASE + I2CR) = I2CR_IEN;
+
+	while (__REG16(I2C_BASE + I2SR) & I2SR_IBB && --timeout)
+		udelay(1);
+
+	return 0;
+}
+
+#endif /* CONFIG_HARD_I2C */