From eda6bee6c7e67b5bd17bdbced0926f5687f686d5 Mon Sep 17 00:00:00 2001 From: Rodolfo Giometti Date: Fri, 26 Nov 2010 17:06:56 +0100 Subject: 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 Signed-off-by: Mauro Barella Signed-off-by: Ben Dooks --- drivers/i2c/busses/i2c-mv64xxx.c | 45 +++++++++++++++++++++++++++++++++------- 1 file changed, 38 insertions(+), 7 deletions(-) (limited to 'drivers/i2c') diff --git a/drivers/i2c/busses/i2c-mv64xxx.c b/drivers/i2c/busses/i2c-mv64xxx.c index 16242063144f..a9941c65f226 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