Remove I2C zero length transfer "HACK" and do real zero length
transfers. This fixes Oops at kernel startup while "scanning" for
TLV320AIC23IDx addresses.
Signed-off-by: Alexander Vasiliev <[EMAIL PROTECTED]>
Signed-off-by: Brad Griffis <[EMAIL PROTECTED]>
Signed-off-by: Dirk Behme <[EMAIL PROTECTED]>
Index: linux-davinci/drivers/i2c/busses/i2c-davinci.c
===================================================================
--- linux-davinci.orig/drivers/i2c/busses/i2c-davinci.c
+++ linux-davinci/drivers/i2c/busses/i2c-davinci.c
@@ -41,11 +41,6 @@
#include <asm/arch/i2c.h>
-/* Hack to enable zero length transfers and smbus quick until clean fix
- * is available
- */
-#define DAVINCI_HACK
-
/* ----- global defines ----------------------------------------------- */
#define DAVINCI_I2C_TIMEOUT (1*HZ)
@@ -118,6 +113,7 @@ struct davinci_i2c_dev {
u8 *buf;
size_t buf_len;
int irq;
+ int stop;
u8 terminate;
struct i2c_adapter adapter;
};
@@ -249,14 +245,6 @@ i2c_davinci_xfer_msg(struct i2c_adapter
u32 flag;
u16 w;
int r;
-#ifdef DAVINCI_HACK
- u8 zero_byte = 0;
-#endif
-
-#ifndef DAVINCI_HACK
- if (msg->len == 0)
- return -EINVAL;
-#endif
if (!pdata)
pdata = &davinci_i2c_platform_data_default;
@@ -267,18 +255,9 @@ i2c_davinci_xfer_msg(struct i2c_adapter
/* set the slave address */
davinci_i2c_write_reg(dev, DAVINCI_I2C_SAR_REG, msg->addr);
-#ifndef DAVINCI_HACK
dev->buf = msg->buf;
dev->buf_len = msg->len;
-#else
- if (msg->len == 0) {
- dev->buf = &zero_byte;
- dev->buf_len = 1;
- } else {
- dev->buf = msg->buf;
- dev->buf_len = msg->len;
- }
-#endif
+ dev->stop = stop;
davinci_i2c_write_reg(dev, DAVINCI_I2C_CNT_REG, dev->buf_len);
@@ -296,6 +275,10 @@ i2c_davinci_xfer_msg(struct i2c_adapter
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);
@@ -306,6 +289,16 @@ i2c_davinci_xfer_msg(struct i2c_adapter
davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, w);
dev->terminate = 0;
+
+ /* 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--;
+ }
+
/* write the data into mode register */
davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag);
@@ -344,11 +337,6 @@ i2c_davinci_xfer_msg(struct i2c_adapter
if (dev->cmd_err & DAVINCI_I2C_STR_NACK) {
if (msg->flags & I2C_M_IGNORE_NAK)
return msg->len;
- if (stop) {
- w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
- MOD_REG_BIT(w, DAVINCI_I2C_MDR_STP, 1);
- davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);
- }
return -EREMOTEIO;
}
return -EIO;
@@ -383,11 +371,7 @@ i2c_davinci_xfer(struct i2c_adapter *ada
static u32 i2c_davinci_func(struct i2c_adapter *adap)
{
-#ifndef DAVINCI_HACK
- return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
-#else
return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
-#endif
}
static inline void terminate_read(struct davinci_i2c_dev *dev)
@@ -404,15 +388,6 @@ static inline void terminate_read(struct
if (!dev->terminate)
dev_err(dev->dev, "RDR IRQ while no data requested\n");
}
-static inline void terminate_write(struct davinci_i2c_dev *dev)
-{
- u16 w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
- w |= DAVINCI_I2C_MDR_RM|DAVINCI_I2C_MDR_STP;
- davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);
-
- if (!dev->terminate)
- dev_err(dev->dev, "TDR IRQ while no data to send\n");
-}
/*
* Interrupt service routine. This gets called whenever an I2C interrupt
@@ -449,6 +424,14 @@ static irqreturn_t i2c_davinci_isr(int t
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);
+ MOD_REG_BIT(w, DAVINCI_I2C_MDR_STP, 1);
+ davinci_i2c_write_reg(dev,
+ DAVINCI_I2C_MDR_REG, w);
+ }
complete(&dev->cmd_complete);
break;
@@ -484,9 +467,6 @@ static irqreturn_t i2c_davinci_isr(int t
davinci_i2c_write_reg(dev,
DAVINCI_I2C_IMR_REG,
w);
- } else {
- /* signal can terminate transfer */
- terminate_write(dev);
}
break;
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