i2c: davinci: Fix smbus Oops with AIC33 usage
This fixes Oops at kernel startup while "scanning" for TLV320AIC23IDx
addresses.
Additional fix from Sudhakar Rajashekhara: I think 'first byte set'
should come after the write because an I2C transaction is being
carried out before configuring the I2C mode register (which has bits
to configure Master, Start condition etc), which causes undefined
behavior.
Signed-off-by: Sudhakar Rajashekhara <sudhakar.raj@ti.com>
Signed-off-by: Alexander Vasiliev <alexvasiljev@gmail.com>
Signed-off-by: Brad Griffis <bgriffis@ti.com>
Signed-off-by: Dirk Behme <dirk.behme@gmail.com>
Acked-by: Kevin Hilman <khilman@deeprootsystems.com>
diff --git a/drivers/i2c/busses/i2c-davinci.c b/drivers/i2c/busses/i2c-davinci.c
index 4523364..43913c1 100644
--- a/drivers/i2c/busses/i2c-davinci.c
+++ b/drivers/i2c/busses/i2c-davinci.c
@@ -113,6 +113,7 @@
u8 *buf;
size_t buf_len;
int irq;
+ int stop;
u8 terminate;
struct i2c_adapter adapter;
};
@@ -250,9 +251,6 @@
u16 w;
int r;
- if (msg->len == 0)
- return -EINVAL;
-
if (!pdata)
pdata = &davinci_i2c_platform_data_default;
/* Introduce a delay, required for some boards (e.g Davinci EVM) */
@@ -264,6 +262,7 @@
dev->buf = msg->buf;
dev->buf_len = msg->len;
+ dev->stop = stop;
davinci_i2c_write_reg(dev, DAVINCI_I2C_CNT_REG, dev->buf_len);
@@ -281,6 +280,10 @@
flag |= DAVINCI_I2C_MDR_TRX;
if (stop)
flag |= DAVINCI_I2C_MDR_STP;
+ if (msg->len == 0) {
+ flag |= DAVINCI_I2C_MDR_RM;
+ flag &= ~DAVINCI_I2C_MDR_STP;
+ }
/* Enable receive or transmit interrupts */
w = davinci_i2c_read_reg(dev, DAVINCI_I2C_IMR_REG);
@@ -291,9 +294,21 @@
davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, w);
dev->terminate = 0;
+
/* write the data into mode register */
davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag);
+ /*
+ * First byte should be set here, not after interrupt,
+ * because transmit-data-ready interrupt can come before
+ * NACK-interrupt during sending of previous message and
+ * ICDXR may have wrong data
+ */
+ if ((!(msg->flags & I2C_M_RD)) && dev->buf_len) {
+ davinci_i2c_write_reg(dev, DAVINCI_I2C_DXR_REG, *dev->buf++);
+ dev->buf_len--;
+ }
+
r = wait_for_completion_interruptible_timeout(&dev->cmd_complete,
dev->adapter.timeout);
if (r == 0) {
@@ -372,7 +387,7 @@
static u32 i2c_davinci_func(struct i2c_adapter *adap)
{
- return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
+ return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
}
static void terminate_read(struct davinci_i2c_dev *dev)
@@ -431,6 +446,14 @@
case DAVINCI_I2C_IVR_ARDY:
davinci_i2c_write_reg(dev,
DAVINCI_I2C_STR_REG, DAVINCI_I2C_STR_ARDY);
+ if (((dev->buf_len == 0) && (dev->stop != 0)) ||
+ (dev->cmd_err & DAVINCI_I2C_STR_NACK)) {
+ w = davinci_i2c_read_reg(dev,
+ DAVINCI_I2C_MDR_REG);
+ w |= DAVINCI_I2C_MDR_STP;
+ davinci_i2c_write_reg(dev,
+ DAVINCI_I2C_MDR_REG, w);
+ }
complete(&dev->cmd_complete);
break;