There is sporadic failures when more as one I2C slave
is on the bus and the processor tries to communicate
with more as one slave.
The problem was seen on a mx35pdk (two I2C slaves,
PMIC controller and CAN/RTC chip).
Signed-off-by: Stefano Babic <sba...@denx.de>
CC: Heiko Schocher <h...@denx.de>
---
drivers/i2c/mxc_i2c.c | 93 +++++++++++++++++++++++++++++++++++++-----------
1 files changed, 71 insertions(+), 22 deletions(-)
diff --git a/drivers/i2c/mxc_i2c.c b/drivers/i2c/mxc_i2c.c
index eead502..5667e68 100755
--- a/drivers/i2c/mxc_i2c.c
+++ b/drivers/i2c/mxc_i2c.c
@@ -72,11 +72,8 @@
#error "define CONFIG_SYS_I2C_MX<Processor>_PORTx to use the mx I2C driver"
#endif
-#ifdef DEBUG
-#define DPRINTF(args...) printf(args)
-#else
-#define DPRINTF(args...)
-#endif
+#define I2C_MAX_TIMEOUT 10000
+#define I2C_MAX_RETRIES 3
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,
@@ -110,37 +107,67 @@ void i2c_init(int speed, int unused)
if (freq / div[i] <= speed)
break;
- DPRINTF("%s: speed: %d\n",__FUNCTION__, speed);
+ debug("%s: speed: %d\n", __FUNCTION__, speed);
writew(i, I2C_BASE + IFDR);
i2c_reset();
}
+static int wait_idle(void)
+{
+ int timeout = I2C_MAX_TIMEOUT;
+
+ while ((readw(I2C_BASE + I2SR) & I2SR_IBB) && --timeout) {
+ writew(0, I2C_BASE + I2SR);
+ udelay(1);
+ }
+ return timeout ? timeout : (!(readw(I2C_BASE + I2SR) & I2SR_IBB));
+}
+
static int wait_busy(void)
{
- int timeout = 10000;
+ int timeout = I2C_MAX_TIMEOUT;
- while (!(readw(I2C_BASE + I2SR) & I2SR_IIF) && --timeout)
+ while (!(readw(I2C_BASE + I2SR) & I2SR_IBB) && --timeout)
udelay(1);
writew(0, I2C_BASE + I2SR); /* clear interrupt */
return timeout;
}
+static int wait_complete(void)
+{
+ int timeout = I2C_MAX_TIMEOUT;
+
+ while ((!(readw(I2C_BASE + I2SR) & I2SR_ICF)) && (--timeout)) {
+ writew(0, I2C_BASE + I2SR);
+ udelay(1);
+ }
+ udelay(200);
+
+ writew(0, I2C_BASE + I2SR); /* clear interrupt */
+
+ return timeout;
+}
+
+
static int tx_byte(u8 byte)
{
writew(byte, I2C_BASE + I2DR);
- if (!wait_busy() || readw(I2C_BASE + I2SR) & I2SR_RX_NO_AK)
+ if (!wait_complete() || readw(I2C_BASE + I2SR) & I2SR_RX_NO_AK)
return -1;
return 0;
}
-static int rx_byte(void)
+static int rx_byte(int last)
{
- if (!wait_busy())
+ if (!wait_complete())
return -1;
+ if (last)
+ writew(I2CR_IEN, I2C_BASE + I2CR);
+
return readw(I2C_BASE + I2DR);
}
@@ -160,24 +187,48 @@ int i2c_probe(uchar chip)
static int i2c_addr(uchar chip, uint addr, int alen)
{
- writew(0, I2C_BASE + I2SR);
- writew(I2CR_IEN | I2CR_MSTA | I2CR_MTX, I2C_BASE + I2CR);
+ int i, retry = 0;
+ for (retry = 0; retry < 3; retry++) {
+ if (wait_idle())
+ break;
+ i2c_reset();
+ for (i = 0; i < I2C_MAX_TIMEOUT; i++)
+ udelay(1);
+ }
+ if (retry >= I2C_MAX_RETRIES) {
+ debug("%s:bus is busy(%x)\n",
+ __func__, readw(I2C_BASE + I2SR));
+ return -1;
+ }
+ writew(I2CR_IEN | I2CR_MSTA | I2CR_MTX, I2C_BASE + I2CR);
- if (tx_byte(chip << 1))
+ if (!wait_busy()) {
+ debug("%s:trigger start fail(%x)\n",
+ __func__, readw(I2C_BASE + I2SR));
return -1;
+ }
+ if (tx_byte(chip << 1) || (readw(I2C_BASE + I2SR) & I2SR_RX_NO_AK)) {
+ debug("%s:chip address cycle fail(%x)\n",
+ __func__, readw(I2C_BASE + I2SR));
+ return -1;
+ }
while (alen--)
- if (tx_byte((addr >> (alen * 8)) & 0xff))
+ if (tx_byte((addr >> (alen * 8)) & 0xff) ||
+ (readw(I2C_BASE + I2SR) & I2SR_RX_NO_AK)) {
+ debug("%s:device address cycle fail(%x)\n",
+ __func__, readw(I2C_BASE + I2SR));
return -1;
+ }
return 0;
}
int i2c_read(uchar chip, uint addr, int alen, uchar *buf, int len)
{
- int timeout = 10000;
+ int timeout = I2C_MAX_TIMEOUT;
int ret;
- DPRINTF("%s chip: 0x%02x addr: 0x%04x alen: %d len: %d\n",
+ debug("%s chip: 0x%02x addr: 0x%04x alen: %d len: %d\n",
__FUNCTION__, chip, addr, alen, len);
if (i2c_addr(chip, addr, alen)) {
@@ -197,7 +248,7 @@ int i2c_read(uchar chip, uint addr, int alen, uchar *buf,
int len)
ret = readw(I2C_BASE + I2DR);
while (len--) {
- if ((ret = rx_byte()) < 0)
+ if ((ret = rx_byte(len == 0)) < 0)
return -1;
*buf++ = ret;
if (len <= 1)
@@ -206,8 +257,6 @@ int i2c_read(uchar chip, uint addr, int alen, uchar *buf,
int len)
I2C_BASE + I2CR);
}
- wait_busy();
-
writew(I2CR_IEN, I2C_BASE + I2CR);
while (readw(I2C_BASE + I2SR) & I2SR_IBB && --timeout)
@@ -218,8 +267,8 @@ int i2c_read(uchar chip, uint addr, int alen, uchar *buf,
int len)
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",
+ int timeout = I2C_MAX_TIMEOUT;
+ debug("%s chip: 0x%02x addr: 0x%04x alen: %d len: %d\n",
__FUNCTION__, chip, addr, alen, len);
if (i2c_addr(chip, addr, alen))
--
1.7.1
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