summaryrefslogtreecommitdiff
path: root/drivers/i2c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/i2c')
-rw-r--r--drivers/i2c/omap24xx_i2c.c209
1 files changed, 117 insertions, 92 deletions
diff --git a/drivers/i2c/omap24xx_i2c.c b/drivers/i2c/omap24xx_i2c.c
index 3febd1ff63..fab49fd969 100644
--- a/drivers/i2c/omap24xx_i2c.c
+++ b/drivers/i2c/omap24xx_i2c.c
@@ -27,7 +27,7 @@
#include "omap24xx_i2c.h"
-#define I2C_TIMEOUT 10
+#define I2C_TIMEOUT 1000
static void wait_for_bb (void);
static u16 wait_for_pin (void);
@@ -159,58 +159,56 @@ static int i2c_read_byte (u8 devaddr, u8 regoffset, u8 * value)
/* no stop bit needed here */
writew (I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_TRX, &i2c_base->con);
- status = wait_for_pin ();
-
- if (status & I2C_STAT_XRDY) {
- /* Important: have to use byte access */
- writeb (regoffset, &i2c_base->data);
- udelay (20000);
- if (readw (&i2c_base->stat) & I2C_STAT_NACK) {
+ /* send register offset */
+ while (1) {
+ status = wait_for_pin();
+ if (status == 0 || status & I2C_STAT_NACK) {
i2c_error = 1;
+ goto read_exit;
+ }
+ if (status & I2C_STAT_XRDY) {
+ /* Important: have to use byte access */
+ writeb(regoffset, &i2c_base->data);
+ writew(I2C_STAT_XRDY, &i2c_base->stat);
+ }
+ if (status & I2C_STAT_ARDY) {
+ writew(I2C_STAT_ARDY, &i2c_base->stat);
+ break;
}
- } else {
- i2c_error = 1;
}
- if (!i2c_error) {
- writew (I2C_CON_EN, &i2c_base->con);
- while (readw(&i2c_base->stat) &
- (I2C_STAT_XRDY | I2C_STAT_ARDY)) {
- udelay (10000);
- /* Have to clear pending interrupt to clear I2C_STAT */
- writew (0xFFFF, &i2c_base->stat);
+ /* set slave address */
+ writew(devaddr, &i2c_base->sa);
+ /* read one byte from slave */
+ writew(1, &i2c_base->cnt);
+ /* need stop bit here */
+ writew(I2C_CON_EN | I2C_CON_MST |
+ I2C_CON_STT | I2C_CON_STP,
+ &i2c_base->con);
+
+ /* receive data */
+ while (1) {
+ status = wait_for_pin();
+ if (status == 0 || status & I2C_STAT_NACK) {
+ i2c_error = 1;
+ goto read_exit;
}
-
- /* set slave address */
- writew (devaddr, &i2c_base->sa);
- /* read one byte from slave */
- writew (1, &i2c_base->cnt);
- /* need stop bit here */
- writew (I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_STP,
- &i2c_base->con);
-
- status = wait_for_pin ();
if (status & I2C_STAT_RRDY) {
#if defined(CONFIG_OMAP243X) || defined(CONFIG_OMAP34XX) || \
defined(CONFIG_OMAP44XX)
- *value = readb (&i2c_base->data);
+ *value = readb(&i2c_base->data);
#else
- *value = readw (&i2c_base->data);
+ *value = readw(&i2c_base->data);
#endif
- udelay (20000);
- } else {
- i2c_error = 1;
+ writew(I2C_STAT_RRDY, &i2c_base->stat);
}
-
- if (!i2c_error) {
- writew (I2C_CON_EN, &i2c_base->con);
- while (readw (&i2c_base->stat) &
- (I2C_STAT_RRDY | I2C_STAT_ARDY)) {
- udelay (10000);
- writew (0xFFFF, &i2c_base->stat);
- }
+ if (status & I2C_STAT_ARDY) {
+ writew(I2C_STAT_ARDY, &i2c_base->stat);
+ break;
}
}
+
+read_exit:
flush_fifo();
writew (0xFFFF, &i2c_base->stat);
writew (0, &i2c_base->cnt);
@@ -220,7 +218,7 @@ static int i2c_read_byte (u8 devaddr, u8 regoffset, u8 * value)
static int i2c_write_byte (u8 devaddr, u8 regoffset, u8 value)
{
int i2c_error = 0;
- u16 status, stat;
+ u16 status;
/* wait until bus not busy */
wait_for_bb ();
@@ -233,49 +231,55 @@ static int i2c_write_byte (u8 devaddr, u8 regoffset, u8 value)
writew (I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_TRX |
I2C_CON_STP, &i2c_base->con);
- /* wait until state change */
- status = wait_for_pin ();
-
- if (status & I2C_STAT_XRDY) {
-#if defined(CONFIG_OMAP243X) || defined(CONFIG_OMAP34XX) || \
- defined(CONFIG_OMAP44XX)
- /* send out 1 byte */
- writeb (regoffset, &i2c_base->data);
- writew (I2C_STAT_XRDY, &i2c_base->stat);
-
- status = wait_for_pin ();
- if ((status & I2C_STAT_XRDY)) {
- /* send out next 1 byte */
- writeb (value, &i2c_base->data);
- writew (I2C_STAT_XRDY, &i2c_base->stat);
- } else {
+ while (1) {
+ status = wait_for_pin();
+ if (status == 0 || status & I2C_STAT_NACK) {
i2c_error = 1;
+ goto write_exit;
}
+ if (status & I2C_STAT_XRDY) {
+#if defined(CONFIG_OMAP243X) || defined(CONFIG_OMAP34XX) || \
+ defined(CONFIG_OMAP44XX)
+ /* send register offset */
+ writeb(regoffset, &i2c_base->data);
+ writew(I2C_STAT_XRDY, &i2c_base->stat);
+
+ while (1) {
+ status = wait_for_pin();
+ if (status == 0 || status & I2C_STAT_NACK) {
+ i2c_error = 1;
+ goto write_exit;
+ }
+ if (status & I2C_STAT_XRDY) {
+ /* send data */
+ writeb(value, &i2c_base->data);
+ writew(I2C_STAT_XRDY, &i2c_base->stat);
+ }
+ if (status & I2C_STAT_ARDY) {
+ writew(I2C_STAT_ARDY, &i2c_base->stat);
+ break;
+ }
+ }
+ break;
#else
- /* send out two bytes */
- writew ((value << 8) + regoffset, &i2c_base->data);
+ /* send out two bytes */
+ writew((value << 8) + regoffset, &i2c_base->data);
+ writew(I2C_STAT_XRDY, &i2c_base->stat);
#endif
- /* must have enough delay to allow BB bit to go low */
- udelay (50000);
- if (readw (&i2c_base->stat) & I2C_STAT_NACK) {
- i2c_error = 1;
}
- } else {
- i2c_error = 1;
+ if (status & I2C_STAT_ARDY) {
+ writew(I2C_STAT_ARDY, &i2c_base->stat);
+ break;
+ }
}
- if (!i2c_error) {
- int eout = 200;
+ wait_for_bb();
- writew (I2C_CON_EN, &i2c_base->con);
- while ((stat = readw (&i2c_base->stat)) || (readw (&i2c_base->con) & I2C_CON_MST)) {
- udelay (1000);
- /* have to read to clear intrrupt */
- writew (0xFFFF, &i2c_base->stat);
- if(--eout == 0) /* better leave with error than hang */
- break;
- }
- }
+ status = readw(&i2c_base->stat);
+ if (status & I2C_STAT_NACK)
+ i2c_error = 1;
+
+write_exit:
flush_fifo();
writew (0xFFFF, &i2c_base->stat);
writew (0, &i2c_base->cnt);
@@ -306,6 +310,7 @@ static void flush_fifo(void)
int i2c_probe (uchar chip)
{
+ u16 status;
int res = 1; /* default = fail */
if (chip == readw (&i2c_base->oa)) {
@@ -321,19 +326,37 @@ int i2c_probe (uchar chip)
writew (chip, &i2c_base->sa);
/* stop bit needed here */
writew (I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_STP, &i2c_base->con);
- /* enough delay for the NACK bit set */
- udelay (50000);
- if (!(readw (&i2c_base->stat) & I2C_STAT_NACK)) {
- res = 0; /* success case */
- flush_fifo();
- writew(0xFFFF, &i2c_base->stat);
- } else {
- writew(0xFFFF, &i2c_base->stat); /* failue, clear sources*/
- writew (readw (&i2c_base->con) | I2C_CON_STP, &i2c_base->con); /* finish up xfer */
- udelay(20000);
- wait_for_bb ();
+ while (1) {
+ status = wait_for_pin();
+ if (status == 0 || status & I2C_STAT_AL) {
+ res = 1;
+ goto probe_exit;
+ }
+ if (status & I2C_STAT_NACK) {
+ res = 1;
+ writew(0xff, &i2c_base->stat);
+ writew (readw (&i2c_base->con) | I2C_CON_STP, &i2c_base->con);
+ wait_for_bb ();
+ break;
+ }
+ if (status & I2C_STAT_ARDY) {
+ writew(I2C_STAT_ARDY, &i2c_base->stat);
+ break;
+ }
+ if (status & I2C_STAT_RRDY) {
+ res = 0;
+#if defined(CONFIG_OMAP243X) || defined(CONFIG_OMAP34XX) || \
+ defined(CONFIG_OMAP44XX)
+ readb(&i2c_base->data);
+#else
+ readw(&i2c_base->data);
+#endif
+ writew(I2C_STAT_RRDY, &i2c_base->stat);
+ }
}
+
+probe_exit:
flush_fifo();
writew (0, &i2c_base->cnt); /* don't allow any more data in...we don't want it.*/
writew(0xFFFF, &i2c_base->stat);
@@ -392,13 +415,13 @@ int i2c_write (uchar chip, uint addr, int alen, uchar * buffer, int len)
static void wait_for_bb (void)
{
- int timeout = 10;
+ int timeout = I2C_TIMEOUT;
u16 stat;
writew(0xFFFF, &i2c_base->stat); /* clear current interruts...*/
while ((stat = readw (&i2c_base->stat) & I2C_STAT_BB) && timeout--) {
writew (stat, &i2c_base->stat);
- udelay (50000);
+ udelay(1000);
}
if (timeout <= 0) {
@@ -411,7 +434,7 @@ static void wait_for_bb (void)
static u16 wait_for_pin (void)
{
u16 status;
- int timeout = 10;
+ int timeout = I2C_TIMEOUT;
do {
udelay (1000);
@@ -424,8 +447,10 @@ static u16 wait_for_pin (void)
if (timeout <= 0) {
printf ("timed out in wait_for_pin: I2C_STAT=%x\n",
readw (&i2c_base->stat));
- writew(0xFFFF, &i2c_base->stat);
-}
+ writew(0xFFFF, &i2c_base->stat);
+ status = 0;
+ }
+
return status;
}
generated by cgit (git 2.34.1) at 2024-12-26 06:52:15 +0000