[U-Boot] [PATCH V2 05/11] I2C: mxc_i2c: address failure with mx35 processor

Stefano Babic
2011-01-20T08:46:28Z

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 <sbabic@denx.de>
CC: Heiko Schocher <hs@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