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i2c-mv64xxx: send repeated START between messages in xfer

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As stated into file include/linux/i2c.h we must send a repeated START
between messages in the same xfer groupset:

 * Except when I2C "protocol mangling" is used, all I2C adapters implement
 * the standard rules for I2C transactions.  Each transaction begins with a
 * START.  That is followed by the slave address, and a bit encoding read
 * versus write.  Then follow all the data bytes, possibly including a byte
 * with SMBus PEC.  The transfer terminates with a NAK, or when all those
 * bytes have been transferred and ACKed.  If this is the last message in a
 * group, it is followed by a STOP.  Otherwise it is followed by the next
 * @i2c_msg transaction segment, beginning with a (repeated) START.

Signed-off-by: Rodolfo Giometti <giometti@linux.it>
Signed-off-by: Mauro Barella <mbarella@vds-it.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
This commit is contained in:
Rodolfo Giometti 2010-11-26 17:06:56 +01:00 committed by Ben Dooks
parent 03ed6a3aa6
commit eda6bee6c7
1 changed files with 38 additions and 7 deletions
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45
drivers/i2c/busses/i2c-mv64xxx.c
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@ -59,6 +59,7 @@ enum {
MV64XXX_I2C_STATE_INVALID,
MV64XXX_I2C_STATE_IDLE,
MV64XXX_I2C_STATE_WAITING_FOR_START_COND,
MV64XXX_I2C_STATE_WAITING_FOR_RESTART,
MV64XXX_I2C_STATE_WAITING_FOR_ADDR_1_ACK,
MV64XXX_I2C_STATE_WAITING_FOR_ADDR_2_ACK,
MV64XXX_I2C_STATE_WAITING_FOR_SLAVE_ACK,
@ -70,6 +71,7 @@ enum {
MV64XXX_I2C_ACTION_INVALID,
MV64XXX_I2C_ACTION_CONTINUE,
MV64XXX_I2C_ACTION_SEND_START,
MV64XXX_I2C_ACTION_SEND_RESTART,
MV64XXX_I2C_ACTION_SEND_ADDR_1,
MV64XXX_I2C_ACTION_SEND_ADDR_2,
MV64XXX_I2C_ACTION_SEND_DATA,
@ -91,6 +93,7 @@ struct mv64xxx_i2c_data {
u32 addr2;
u32 bytes_left;
u32 byte_posn;
u32 send_stop;
u32 block;
int rc;
u32 freq_m;
@ -159,8 +162,15 @@ mv64xxx_i2c_fsm(struct mv64xxx_i2c_data *drv_data, u32 status)
if ((drv_data->bytes_left == 0)
|| (drv_data->aborting
&& (drv_data->byte_posn != 0))) {
drv_data->action = MV64XXX_I2C_ACTION_SEND_STOP;
drv_data->state = MV64XXX_I2C_STATE_IDLE;
if (drv_data->send_stop) {
drv_data->action = MV64XXX_I2C_ACTION_SEND_STOP;
drv_data->state = MV64XXX_I2C_STATE_IDLE;
} else {
drv_data->action =
MV64XXX_I2C_ACTION_SEND_RESTART;
drv_data->state =
MV64XXX_I2C_STATE_WAITING_FOR_RESTART;
}
} else {
drv_data->action = MV64XXX_I2C_ACTION_SEND_DATA;
drv_data->state =
@ -228,6 +238,15 @@ static void
mv64xxx_i2c_do_action(struct mv64xxx_i2c_data *drv_data)
{
switch(drv_data->action) {
case MV64XXX_I2C_ACTION_SEND_RESTART:
drv_data->cntl_bits |= MV64XXX_I2C_REG_CONTROL_START;
drv_data->cntl_bits &= ~MV64XXX_I2C_REG_CONTROL_INTEN;
writel(drv_data->cntl_bits,
drv_data->reg_base + MV64XXX_I2C_REG_CONTROL);
drv_data->block = 0;
wake_up_interruptible(&drv_data->waitq);
break;
case MV64XXX_I2C_ACTION_CONTINUE:
writel(drv_data->cntl_bits,
drv_data->reg_base + MV64XXX_I2C_REG_CONTROL);
@ -386,7 +405,8 @@ mv64xxx_i2c_wait_for_completion(struct mv64xxx_i2c_data *drv_data)
}
static int
mv64xxx_i2c_execute_msg(struct mv64xxx_i2c_data *drv_data, struct i2c_msg *msg)
mv64xxx_i2c_execute_msg(struct mv64xxx_i2c_data *drv_data, struct i2c_msg *msg,
int is_first, int is_last)
{
unsigned long flags;
@ -406,10 +426,18 @@ mv64xxx_i2c_execute_msg(struct mv64xxx_i2c_data *drv_data, struct i2c_msg *msg)
drv_data->bytes_left--;
}
} else {
drv_data->action = MV64XXX_I2C_ACTION_SEND_START;
drv_data->state = MV64XXX_I2C_STATE_WAITING_FOR_START_COND;
if (is_first) {
drv_data->action = MV64XXX_I2C_ACTION_SEND_START;
drv_data->state =
MV64XXX_I2C_STATE_WAITING_FOR_START_COND;
} else {
drv_data->action = MV64XXX_I2C_ACTION_SEND_ADDR_1;
drv_data->state =
MV64XXX_I2C_STATE_WAITING_FOR_ADDR_1_ACK;
}
}
drv_data->send_stop = is_last;
drv_data->block = 1;
mv64xxx_i2c_do_action(drv_data);
spin_unlock_irqrestore(&drv_data->lock, flags);
@ -437,9 +465,12 @@ mv64xxx_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
struct mv64xxx_i2c_data *drv_data = i2c_get_adapdata(adap);
int i, rc;
for (i=0; i<num; i++)
if ((rc = mv64xxx_i2c_execute_msg(drv_data, &msgs[i])) < 0)
for (i = 0; i < num; i++) {
rc = mv64xxx_i2c_execute_msg(drv_data, &msgs[i],
i == 0, i + 1 == num);
if (rc < 0)
return rc;
}
return num;
}