Commit b460b15b authored by Stefan Eichenberger's avatar Stefan Eichenberger Committed by Andi Shyti
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i2c: imx: separate atomic, dma and non-dma use case 



Separate the atomic, dma and non-dma use case as a preparation step for
moving the non-dma use case to the isr to avoid rescheduling while a
transfer is in progress.

Signed-off-by: default avatarStefan Eichenberger <stefan.eichenberger@toradex.com>
Reviewed-by: default avatarFrank Li <Frank.Li@nxp.com>
Acked-by: default avatarOleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: default avatarAndi Shyti <andi.shyti@kernel.org>
parent 6692694a

drivers/i2c/busses/i2c-imx.c

+70 −37
Original line number Diff line number Diff line
@@ -1011,6 +1011,43 @@ static int i2c_imx_dma_write(struct imx_i2c_struct *i2c_imx, 
	return i2c_imx_acked(i2c_imx);

}



static int i2c_imx_prepare_read(struct imx_i2c_struct *i2c_imx,

				struct i2c_msg *msgs, bool atomic,

				bool use_dma)

{

	int result;

	unsigned int temp = 0;



	/* write slave address */

	imx_i2c_write_reg(i2c_8bit_addr_from_msg(msgs), i2c_imx, IMX_I2C_I2DR);

	result = i2c_imx_trx_complete(i2c_imx, atomic);

	if (result)

		return result;

	result = i2c_imx_acked(i2c_imx);

	if (result)

		return result;



	dev_dbg(&i2c_imx->adapter.dev, "<%s> setup bus\n", __func__);



	/* setup bus to read data */

	temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);

	temp &= ~I2CR_MTX;



	/*

	 * Reset the I2CR_TXAK flag initially for SMBus block read since the

	 * length is unknown

	 */

	if (msgs->len - 1)

		temp &= ~I2CR_TXAK;

	if (use_dma)

		temp |= I2CR_DMAEN;



	imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);

	imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR); /* dummy read */



	return 0;

}



static int i2c_imx_dma_read(struct imx_i2c_struct *i2c_imx,

			struct i2c_msg *msgs, bool is_lastmsg)

{
@@ -1021,6 +1058,11 @@ static int i2c_imx_dma_read(struct imx_i2c_struct *i2c_imx, 
	struct imx_i2c_dma *dma = i2c_imx->dma;

	struct device *dev = &i2c_imx->adapter.dev;



	result = i2c_imx_prepare_read(i2c_imx, msgs, false, true);

	if (result)

		return result;



	dev_dbg(&i2c_imx->adapter.dev, "<%s> read data\n", __func__);



	dma->chan_using = dma->chan_rx;

	dma->dma_transfer_dir = DMA_DEV_TO_MEM;
@@ -1131,50 +1173,24 @@ static int i2c_imx_write(struct imx_i2c_struct *i2c_imx, struct i2c_msg *msgs, 
	return 0;

}



static int i2c_imx_atomic_write(struct imx_i2c_struct *i2c_imx, struct i2c_msg *msgs)

{

	return i2c_imx_write(i2c_imx, msgs, true);

}



static int i2c_imx_read(struct imx_i2c_struct *i2c_imx, struct i2c_msg *msgs,

			bool is_lastmsg, bool atomic)

{

	int i, result;

	unsigned int temp;

	int block_data = msgs->flags & I2C_M_RECV_LEN;

	int use_dma = i2c_imx->dma && msgs->flags & I2C_M_DMA_SAFE &&

		msgs->len >= DMA_THRESHOLD && !block_data;



	dev_dbg(&i2c_imx->adapter.dev,

		"<%s> write slave address: addr=0x%x\n",

		__func__, i2c_8bit_addr_from_msg(msgs));



	/* write slave address */

	imx_i2c_write_reg(i2c_8bit_addr_from_msg(msgs), i2c_imx, IMX_I2C_I2DR);

	result = i2c_imx_trx_complete(i2c_imx, atomic);

	result = i2c_imx_prepare_read(i2c_imx, msgs, atomic, false);

	if (result)

		return result;

	result = i2c_imx_acked(i2c_imx);

	if (result)

		return result;



	dev_dbg(&i2c_imx->adapter.dev, "<%s> setup bus\n", __func__);



	/* setup bus to read data */

	temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);

	temp &= ~I2CR_MTX;



	/*

	 * Reset the I2CR_TXAK flag initially for SMBus block read since the

	 * length is unknown

	 */

	if ((msgs->len - 1) || block_data)

		temp &= ~I2CR_TXAK;

	if (use_dma)

		temp |= I2CR_DMAEN;

	imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);

	imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR); /* dummy read */



	dev_dbg(&i2c_imx->adapter.dev, "<%s> read data\n", __func__);



	if (use_dma)

		return i2c_imx_dma_read(i2c_imx, msgs, is_lastmsg);



	/* read data */

	for (i = 0; i < msgs->len; i++) {

		u8 len = 0;
@@ -1241,6 +1257,12 @@ static int i2c_imx_read(struct imx_i2c_struct *i2c_imx, struct i2c_msg *msgs, 
	return 0;

}



static int i2c_imx_atomic_read(struct imx_i2c_struct *i2c_imx, struct i2c_msg *msgs,

			       bool is_lastmsg)

{

	return i2c_imx_read(i2c_imx, msgs, is_lastmsg, true);

}



static int i2c_imx_xfer_common(struct i2c_adapter *adapter,

			       struct i2c_msg *msgs, int num, bool atomic)

{
@@ -1248,6 +1270,7 @@ static int i2c_imx_xfer_common(struct i2c_adapter *adapter, 
	int result;

	bool is_lastmsg = false;

	struct imx_i2c_struct *i2c_imx = i2c_get_adapdata(adapter);

	int use_dma = 0;



	/* Start I2C transfer */

	result = i2c_imx_start(i2c_imx, atomic);
@@ -1300,15 +1323,25 @@ static int i2c_imx_xfer_common(struct i2c_adapter *adapter, 
			(temp & I2SR_SRW ? 1 : 0), (temp & I2SR_IIF ? 1 : 0),

			(temp & I2SR_RXAK ? 1 : 0));

#endif



		use_dma = i2c_imx->dma && msgs[i].len >= DMA_THRESHOLD &&

			msgs[i].flags & I2C_M_DMA_SAFE;

		if (msgs[i].flags & I2C_M_RD) {

			result = i2c_imx_read(i2c_imx, &msgs[i], is_lastmsg, atomic);

			int block_data = msgs->flags & I2C_M_RECV_LEN;



			if (atomic)

				result = i2c_imx_atomic_read(i2c_imx, &msgs[i], is_lastmsg);

			else if (use_dma && !block_data)

				result = i2c_imx_dma_read(i2c_imx, &msgs[i], is_lastmsg);

			else

				result = i2c_imx_read(i2c_imx, &msgs[i], is_lastmsg, false);

		} else {

			if (!atomic &&

			    i2c_imx->dma && msgs[i].len >= DMA_THRESHOLD &&

				msgs[i].flags & I2C_M_DMA_SAFE)

			if (atomic)

				result = i2c_imx_atomic_write(i2c_imx, &msgs[i]);

			else if (use_dma)

				result = i2c_imx_dma_write(i2c_imx, &msgs[i]);

			else

				result = i2c_imx_write(i2c_imx, &msgs[i], atomic);

				result = i2c_imx_write(i2c_imx, &msgs[i], false);

		}

		if (result)

			goto fail0;