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Commit c8f5af2f authored by Laxman Dewangan's avatar Laxman Dewangan Committed by Wolfram Sang
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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: default avatarLaxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: default avatarWolfram Sang <w.sang@pengutronix.de>
parent a7018104

drivers/i2c/busses/i2c-tegra.c

+26 −5
Original line number Diff line number Diff line
@@ -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 = {