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authorwdenk <wdenk>2002-11-03 00:24:07 +0000
committerwdenk <wdenk>2002-11-03 00:24:07 +0000
commitc609719b8d1b2dca590e0ed499016d041203e403 (patch)
tree7ea1755d80903ff972f312a249eb856061d40e15 /board/pcippc2/i2c.c
parent5b1d713721c3ea02549940133f09236783dda1f9 (diff)
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Initial revision
Diffstat (limited to 'board/pcippc2/i2c.c')
-rw-r--r--board/pcippc2/i2c.c257
1 files changed, 257 insertions, 0 deletions
diff --git a/board/pcippc2/i2c.c b/board/pcippc2/i2c.c
new file mode 100644
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+++ b/board/pcippc2/i2c.c
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+/*
+ * (C) Copyright 2002
+ * Wolfgang Denk, DENX Software Engineering, wd@denx.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 <config.h>
+#include <common.h>
+#include <asm/io.h>
+
+#include "hardware.h"
+#include "i2c.h"
+
+static void i2c_start (void);
+static void i2c_stop (void);
+static int i2c_write (u8 data);
+static void i2c_read (u8 * data);
+
+static inline void i2c_port_start (void);
+static inline void i2c_clock (unsigned int val);
+static inline void i2c_data (unsigned int val);
+static inline unsigned int
+ i2c_in (void);
+static inline void i2c_write_bit (unsigned int val);
+static inline unsigned int
+ i2c_read_bit (void);
+
+static inline void i2c_udelay (unsigned int time);
+
+int i2c_read_byte (
+ u8 * data,
+ u8 dev,
+ u8 offset)
+{
+ int err = 0;
+
+ i2c_start();
+
+ err = ! i2c_write(dev);
+
+ if (! err)
+ {
+ err = ! i2c_write(offset);
+ }
+
+ if (! err)
+ {
+ i2c_start();
+ }
+
+ if (! err)
+ {
+ err = ! i2c_write(dev | 0x01);
+ }
+
+ if (! err)
+ {
+ i2c_read(data);
+ }
+
+ i2c_stop();
+
+ return ! err;
+}
+
+static inline void i2c_udelay (
+ unsigned int time)
+{
+ int v;
+
+ asm volatile("mtdec %0" : : "r" (time * ((CFG_BUS_CLK / 4) / 1000000)));
+
+ do
+ {
+ asm volatile("isync; mfdec %0" : "=r" (v));
+ } while (v >= 0);
+}
+
+ /* Low-level hardware access
+ */
+
+#define BIT_GPDATA 0x80000000
+#define BIT_GPCLK 0x40000000
+
+static inline void i2c_port_start (void)
+{
+ out32(REG(CPC0, GPDIR), in32(REG(CPC0, GPDIR)) & ~(BIT_GPCLK | BIT_GPDATA));
+ out32(REG(CPC0, GPOUT), in32(REG(CPC0, GPOUT)) & ~(BIT_GPCLK | BIT_GPDATA));
+ iobarrier_rw();
+
+ i2c_udelay(1);
+}
+
+static inline void i2c_clock (
+ unsigned int val)
+{
+ if (val)
+ {
+ out32(REG(CPC0, GPDIR), in32(REG(CPC0, GPDIR)) & ~BIT_GPCLK);
+ }
+ else
+ {
+ out32(REG(CPC0, GPDIR), in32(REG(CPC0, GPDIR)) | BIT_GPCLK);
+ }
+
+ iobarrier_rw();
+
+ i2c_udelay(1);
+}
+
+static inline void i2c_data (
+ unsigned int val)
+{
+ if (val)
+ {
+ out32(REG(CPC0, GPDIR), in32(REG(CPC0, GPDIR)) & ~BIT_GPDATA);
+ }
+ else
+ {
+ out32(REG(CPC0, GPDIR), in32(REG(CPC0, GPDIR)) | BIT_GPDATA);
+ }
+
+ iobarrier_rw();
+
+ i2c_udelay(1);
+}
+
+static inline unsigned int i2c_in (void)
+{
+ unsigned int val = ((in32(REG(CPC0, GPIN)) & BIT_GPDATA) != 0)?1:0;
+
+ iobarrier_rw();
+
+ return val;
+}
+
+
+ /* Protocol implementation
+ */
+
+static inline void i2c_write_bit (
+ unsigned int val)
+{
+ i2c_data(val);
+ i2c_udelay(10);
+ i2c_clock(1);
+ i2c_udelay(10);
+ i2c_clock(0);
+ i2c_udelay(10);
+}
+
+static inline unsigned int i2c_read_bit (void)
+{
+ unsigned int val;
+
+ i2c_data(1);
+ i2c_udelay(10);
+
+ i2c_clock(1);
+ i2c_udelay(10);
+
+ val = i2c_in();
+
+ i2c_clock(0);
+ i2c_udelay(10);
+
+ return val;
+}
+
+unsigned int i2c_reset (void)
+{
+ unsigned int val;
+ int i;
+
+ i2c_port_start();
+
+ i=0;
+ do {
+ i2c_udelay(10);
+ i2c_clock(0);
+ i2c_udelay(10);
+ i2c_clock(1);
+ i2c_udelay(10);
+ val = i2c_in();
+ i++;
+ } while ((i<9)&&(val==0));
+ return (val);
+}
+
+
+static void i2c_start (void)
+{
+ i2c_data(1);
+ i2c_clock(1);
+ i2c_udelay(10);
+ i2c_data(0);
+ i2c_udelay(10);
+ i2c_clock(0);
+ i2c_udelay(10);
+}
+
+static void i2c_stop (void)
+{
+ i2c_data(0);
+ i2c_udelay(10);
+ i2c_clock(1);
+ i2c_udelay(10);
+ i2c_data(1);
+ i2c_udelay(10);
+}
+
+static int i2c_write (
+ u8 data)
+{
+ unsigned int i;
+
+ for (i = 0; i < 8; i++)
+ {
+ i2c_write_bit(data >> 7);
+ data <<= 1;
+ }
+
+ return i2c_read_bit() == 0;
+}
+
+static void i2c_read (
+ u8 * data)
+{
+ unsigned int i;
+ u8 val = 0;
+
+ for (i = 0; i < 8; i++)
+ {
+ val <<= 1;
+ val |= i2c_read_bit();
+ }
+
+ *data = val;
+ i2c_write_bit(1); /* NoAck */
+}