diff options
| author | Laxman Dewangan <ldewangan@nvidia.com> | 2012-06-13 15:42:38 +0530 |
|---|---|---|
| committer | Wolfram Sang <w.sang@pengutronix.de> | 2012-07-08 12:49:15 +0200 |
| commit | c8f5af2f507d7f97a11065b98ec9f6c22aad8af0 (patch) | |
| tree | b2463605170abcce28e22d58e47ed0014a4ab45f /drivers/i2c | |
| parent | a70181049fc7b619ddc10cc1b956e7ee04b5bddd (diff) | |
| download | linux-c8f5af2f507d7f97a11065b98ec9f6c22aad8af0.tar.bz2 | |
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>
Diffstat (limited to 'drivers/i2c')
| -rw-r--r-- | drivers/i2c/busses/i2c-tegra.c | 31 |
1 files changed, 26 insertions, 5 deletions
diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c index 68433aeaa2e8..c4593a24331c 100644 --- a/drivers/i2c/busses/i2c-tegra.c +++ b/drivers/i2c/busses/i2c-tegra.c @@ -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 @@ err: } 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 = { |