This patch removes the "magic number" delays and instead
monitors state changes in the status register bits.
Signed-off-by: Steve Sakoman <steve.sako...@linaro.org>
---
drivers/i2c/omap24xx_i2c.c | 41 ++++++++++++++++++++++++++++++-----------
1 files changed, 30 insertions(+), 11 deletions(-)
diff --git a/drivers/i2c/omap24xx_i2c.c b/drivers/i2c/omap24xx_i2c.c
index 828264e..eb153fb 100644
--- a/drivers/i2c/omap24xx_i2c.c
+++ b/drivers/i2c/omap24xx_i2c.c
@@ -310,6 +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)) {
@@ -325,19 +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) {
+ 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);
--
1.7.0.4
_______________________________________________
U-Boot mailing list
U-Boot@lists.denx.de
http://lists.denx.de/mailman/listinfo/u-boot
