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i2c: tegra: support for I2C_M_NOSTART functionality 

Adding support for functionality I2C_M_NOSTART.
When multiple message transfer request made through i2c
and if any message is flagged with I2C_M_NOSTART then
it will not send the start/repeat-start and address of
that message i.e. sends data directly.

Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
This commit is contained in:
Laxman Dewangan 2012-06-13 15:42:38 +05:30 committed by Wolfram Sang
parent a70181049f
commit c8f5af2f50
1 changed files with 26 additions and 5 deletions
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31
drivers/i2c/busses/i2c-tegra.c
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@ -97,8 +97,21 @@
#define I2C_HEADER_10BIT_ADDR (1<<18)
#define I2C_HEADER_IE_ENABLE (1<<17)
#define I2C_HEADER_REPEAT_START (1<<16)
#define I2C_HEADER_CONTINUE_XFER (1<<15)
#define I2C_HEADER_MASTER_ADDR_SHIFT 12
#define I2C_HEADER_SLAVE_ADDR_SHIFT 1
/*
* msg_end_type: The bus control which need to be send at end of transfer.
* @MSG_END_STOP: Send stop pulse at end of transfer.
* @MSG_END_REPEAT_START: Send repeat start at end of transfer.
* @MSG_END_CONTINUE: The following on message is coming and so do not send
* stop or repeat start.
*/
enum msg_end_type {
MSG_END_STOP,
MSG_END_REPEAT_START,
MSG_END_CONTINUE,
};
/**
* struct tegra_i2c_dev - per device i2c context
@ -453,7 +466,7 @@ static irqreturn_t tegra_i2c_isr(int irq, void *dev_id)
}
static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
struct i2c_msg *msg, int stop)
struct i2c_msg *msg, enum msg_end_type end_state)
{
u32 packet_header;
u32 int_mask;
@ -480,7 +493,9 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
i2c_writel(i2c_dev, packet_header, I2C_TX_FIFO);
packet_header = I2C_HEADER_IE_ENABLE;
if (!stop)
if (end_state == MSG_END_CONTINUE)
packet_header |= I2C_HEADER_CONTINUE_XFER;
else if (end_state == MSG_END_REPEAT_START)
packet_header |= I2C_HEADER_REPEAT_START;
if (msg->flags & I2C_M_TEN) {
packet_header |= msg->addr;
@ -552,8 +567,14 @@ static int tegra_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[],
clk_enable(i2c_dev->clk);
for (i = 0; i < num; i++) {
int stop = (i == (num - 1)) ? 1 : 0;
ret = tegra_i2c_xfer_msg(i2c_dev, &msgs[i], stop);
enum msg_end_type end_type = MSG_END_STOP;
if (i < (num - 1)) {
if (msgs[i + 1].flags & I2C_M_NOSTART)
end_type = MSG_END_CONTINUE;
else
end_type = MSG_END_REPEAT_START;
}
ret = tegra_i2c_xfer_msg(i2c_dev, &msgs[i], end_type);
if (ret)
break;
}
@ -564,7 +585,7 @@ static int tegra_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[],
static u32 tegra_i2c_func(struct i2c_adapter *adap)
{
return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_10BIT_ADDR |
I2C_FUNC_PROTOCOL_MANGLING;
I2C_FUNC_PROTOCOL_MANGLING | I2C_FUNC_NOSTART;
}
static const struct i2c_algorithm tegra_i2c_algo = {