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author | Rodolfo Giometti <giometti@linux.it> | 2010-11-26 16:06:56 (GMT) |
---|---|---|
committer | Ben Dooks <ben-linux@fluff.org> | 2011-01-04 01:19:43 (GMT) |
commit | eda6bee6c7e67b5bd17bdbced0926f5687f686d5 (patch) | |
tree | 3f2be4bb958e1fd320494973d55c45f91381ef4a /drivers/i2c | |
parent | 03ed6a3aa600c48593c3984812fda2d5945ddb46 (diff) | |
download | linux-fsl-qoriq-eda6bee6c7e67b5bd17bdbced0926f5687f686d5.tar.xz |
i2c-mv64xxx: send repeated START between messages in xfer
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>
Diffstat (limited to 'drivers/i2c')
-rw-r--r-- | drivers/i2c/busses/i2c-mv64xxx.c | 45 |
1 files changed, 38 insertions, 7 deletions
diff --git a/drivers/i2c/busses/i2c-mv64xxx.c b/drivers/i2c/busses/i2c-mv64xxx.c index 1624206..a9941c6 100644 --- a/drivers/i2c/busses/i2c-mv64xxx.c +++ b/drivers/i2c/busses/i2c-mv64xxx.c @@ -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; } |