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path: root/drivers/i2c/omap24xx_i2c.c
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Diffstat (limited to 'drivers/i2c/omap24xx_i2c.c')
-rw-r--r--drivers/i2c/omap24xx_i2c.c329
1 files changed, 329 insertions, 0 deletions
diff --git a/drivers/i2c/omap24xx_i2c.c b/drivers/i2c/omap24xx_i2c.c
new file mode 100644
index 0000000..7dab786
--- /dev/null
+++ b/drivers/i2c/omap24xx_i2c.c
@@ -0,0 +1,329 @@
+/*
+ * Basic I2C functions
+ *
+ * Copyright (c) 2004 Texas Instruments
+ *
+ * This package is free software; you can redistribute it and/or
+ * modify it under the terms of the license found in the file
+ * named COPYING that should have accompanied this file.
+ *
+ * THIS PACKAGE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
+ * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * Author: Jian Zhang jzhang@ti.com, Texas Instruments
+ *
+ * Copyright (c) 2003 Wolfgang Denk, wd@denx.de
+ * Rewritten to fit into the current U-Boot framework
+ *
+ * Adapted for OMAP2420 I2C, r-woodruff2@ti.com
+ *
+ */
+
+#include <common.h>
+
+#ifdef CONFIG_DRIVER_OMAP24XX_I2C
+
+#include <asm/arch/i2c.h>
+#include <asm/io.h>
+
+#define inw(a) __raw_readw(a)
+#define outw(a,v) __raw_writew(a,v)
+
+static void wait_for_bb (void);
+static u16 wait_for_pin (void);
+static void flush_fifo(void);
+
+void i2c_init (int speed, int slaveadd)
+{
+ u16 scl;
+
+ outw(0x2, I2C_SYSC); /* for ES2 after soft reset */
+ udelay(1000);
+ outw(0x0, I2C_SYSC); /* will probably self clear but */
+
+ if (inw (I2C_CON) & I2C_CON_EN) {
+ outw (0, I2C_CON);
+ udelay (50000);
+ }
+
+ /* 12Mhz I2C module clock */
+ outw (0, I2C_PSC);
+ speed = speed/1000; /* 100 or 400 */
+ scl = ((12000/(speed*2)) - 7); /* use 7 when PSC = 0 */
+ outw (scl, I2C_SCLL);
+ outw (scl, I2C_SCLH);
+ /* own address */
+ outw (slaveadd, I2C_OA);
+ outw (I2C_CON_EN, I2C_CON);
+
+ /* have to enable intrrupts or OMAP i2c module doesn't work */
+ outw (I2C_IE_XRDY_IE | I2C_IE_RRDY_IE | I2C_IE_ARDY_IE |
+ I2C_IE_NACK_IE | I2C_IE_AL_IE, I2C_IE);
+ udelay (1000);
+ flush_fifo();
+ outw (0xFFFF, I2C_STAT);
+ outw (0, I2C_CNT);
+}
+
+static int i2c_read_byte (u8 devaddr, u8 regoffset, u8 * value)
+{
+ int i2c_error = 0;
+ u16 status;
+
+ /* wait until bus not busy */
+ wait_for_bb ();
+
+ /* one byte only */
+ outw (1, I2C_CNT);
+ /* set slave address */
+ outw (devaddr, I2C_SA);
+ /* no stop bit needed here */
+ outw (I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_TRX, I2C_CON);
+
+ status = wait_for_pin ();
+
+ if (status & I2C_STAT_XRDY) {
+ /* Important: have to use byte access */
+ *(volatile u8 *) (I2C_DATA) = regoffset;
+ udelay (20000);
+ if (inw (I2C_STAT) & I2C_STAT_NACK) {
+ i2c_error = 1;
+ }
+ } else {
+ i2c_error = 1;
+ }
+
+ if (!i2c_error) {
+ /* free bus, otherwise we can't use a combined transction */
+ outw (0, I2C_CON);
+ while (inw (I2C_STAT) || (inw (I2C_CON) & I2C_CON_MST)) {
+ udelay (10000);
+ /* Have to clear pending interrupt to clear I2C_STAT */
+ outw (0xFFFF, I2C_STAT);
+ }
+
+ wait_for_bb ();
+ /* set slave address */
+ outw (devaddr, I2C_SA);
+ /* read one byte from slave */
+ outw (1, I2C_CNT);
+ /* need stop bit here */
+ outw (I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_STP,
+ I2C_CON);
+
+ status = wait_for_pin ();
+ if (status & I2C_STAT_RRDY) {
+ *value = inw (I2C_DATA);
+ udelay (20000);
+ } else {
+ i2c_error = 1;
+ }
+
+ if (!i2c_error) {
+ outw (I2C_CON_EN, I2C_CON);
+ while (inw (I2C_STAT)
+ || (inw (I2C_CON) & I2C_CON_MST)) {
+ udelay (10000);
+ outw (0xFFFF, I2C_STAT);
+ }
+ }
+ }
+ flush_fifo();
+ outw (0xFFFF, I2C_STAT);
+ outw (0, I2C_CNT);
+ return i2c_error;
+}
+
+static int i2c_write_byte (u8 devaddr, u8 regoffset, u8 value)
+{
+ int i2c_error = 0;
+ u16 status, stat;
+
+ /* wait until bus not busy */
+ wait_for_bb ();
+
+ /* two bytes */
+ outw (2, I2C_CNT);
+ /* set slave address */
+ outw (devaddr, I2C_SA);
+ /* stop bit needed here */
+ outw (I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_TRX |
+ I2C_CON_STP, I2C_CON);
+
+ /* wait until state change */
+ status = wait_for_pin ();
+
+ if (status & I2C_STAT_XRDY) {
+ /* send out two bytes */
+ outw ((value << 8) + regoffset, I2C_DATA);
+ /* must have enough delay to allow BB bit to go low */
+ udelay (50000);
+ if (inw (I2C_STAT) & I2C_STAT_NACK) {
+ i2c_error = 1;
+ }
+ } else {
+ i2c_error = 1;
+ }
+
+ if (!i2c_error) {
+ int eout = 200;
+
+ outw (I2C_CON_EN, I2C_CON);
+ while ((stat = inw (I2C_STAT)) || (inw (I2C_CON) & I2C_CON_MST)) {
+ udelay (1000);
+ /* have to read to clear intrrupt */
+ outw (0xFFFF, I2C_STAT);
+ if(--eout == 0) /* better leave with error than hang */
+ break;
+ }
+ }
+ flush_fifo();
+ outw (0xFFFF, I2C_STAT);
+ outw (0, I2C_CNT);
+ return i2c_error;
+}
+
+static void flush_fifo(void)
+{ u16 stat;
+
+ /* note: if you try and read data when its not there or ready
+ * you get a bus error
+ */
+ while(1){
+ stat = inw(I2C_STAT);
+ if(stat == I2C_STAT_RRDY){
+ inw(I2C_DATA);
+ outw(I2C_STAT_RRDY,I2C_STAT);
+ udelay(1000);
+ }else
+ break;
+ }
+}
+
+int i2c_probe (uchar chip)
+{
+ int res = 1; /* default = fail */
+
+ if (chip == inw (I2C_OA)) {
+ return res;
+ }
+
+ /* wait until bus not busy */
+ wait_for_bb ();
+
+ /* try to read one byte */
+ outw (1, I2C_CNT);
+ /* set slave address */
+ outw (chip, I2C_SA);
+ /* stop bit needed here */
+ outw (I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_STP, I2C_CON);
+ /* enough delay for the NACK bit set */
+ udelay (50000);
+
+ if (!(inw (I2C_STAT) & I2C_STAT_NACK)) {
+ res = 0; /* success case */
+ flush_fifo();
+ outw(0xFFFF, I2C_STAT);
+ } else {
+ outw(0xFFFF, I2C_STAT); /* failue, clear sources*/
+ outw (inw (I2C_CON) | I2C_CON_STP, I2C_CON); /* finish up xfer */
+ udelay(20000);
+ wait_for_bb ();
+ }
+ flush_fifo();
+ outw (0, I2C_CNT); /* don't allow any more data in...we don't want it.*/
+ outw(0xFFFF, I2C_STAT);
+ return res;
+}
+
+int i2c_read (uchar chip, uint addr, int alen, uchar * buffer, int len)
+{
+ int i;
+
+ if (alen > 1) {
+ printf ("I2C read: addr len %d not supported\n", alen);
+ return 1;
+ }
+
+ if (addr + len > 256) {
+ printf ("I2C read: address out of range\n");
+ return 1;
+ }
+
+ for (i = 0; i < len; i++) {
+ if (i2c_read_byte (chip, addr + i, &buffer[i])) {
+ printf ("I2C read: I/O error\n");
+ i2c_init (CFG_I2C_SPEED, CFG_I2C_SLAVE);
+ return 1;
+ }
+ }
+
+ return 0;
+}
+
+int i2c_write (uchar chip, uint addr, int alen, uchar * buffer, int len)
+{
+ int i;
+
+ if (alen > 1) {
+ printf ("I2C read: addr len %d not supported\n", alen);
+ return 1;
+ }
+
+ if (addr + len > 256) {
+ printf ("I2C read: address out of range\n");
+ return 1;
+ }
+
+ for (i = 0; i < len; i++) {
+ if (i2c_write_byte (chip, addr + i, buffer[i])) {
+ printf ("I2C read: I/O error\n");
+ i2c_init (CFG_I2C_SPEED, CFG_I2C_SLAVE);
+ return 1;
+ }
+ }
+
+ return 0;
+}
+
+static void wait_for_bb (void)
+{
+ int timeout = 10;
+ u16 stat;
+
+ outw(0xFFFF, I2C_STAT); /* clear current interruts...*/
+ while ((stat = inw (I2C_STAT) & I2C_STAT_BB) && timeout--) {
+ outw (stat, I2C_STAT);
+ udelay (50000);
+ }
+
+ if (timeout <= 0) {
+ printf ("timed out in wait_for_bb: I2C_STAT=%x\n",
+ inw (I2C_STAT));
+ }
+ outw(0xFFFF, I2C_STAT); /* clear delayed stuff*/
+}
+
+static u16 wait_for_pin (void)
+{
+ u16 status;
+ int timeout = 10;
+
+ do {
+ udelay (1000);
+ status = inw (I2C_STAT);
+ } while ( !(status &
+ (I2C_STAT_ROVR | I2C_STAT_XUDF | I2C_STAT_XRDY |
+ I2C_STAT_RRDY | I2C_STAT_ARDY | I2C_STAT_NACK |
+ I2C_STAT_AL)) && timeout--);
+
+ if (timeout <= 0) {
+ printf ("timed out in wait_for_pin: I2C_STAT=%x\n",
+ inw (I2C_STAT));
+ outw(0xFFFF, I2C_STAT);
+}
+ return status;
+}
+
+#endif /* CONFIG_DRIVER_OMAP24XX_I2C */
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