Commit 8e8782c7 authored by Kaushal Butala's avatar Kaushal Butala Committed by Wolfram Sang
Browse files

i2c: imx: add SMBus block read support 



The smbus block read is not currently supported for imx i2c devices.
This patchset adds the support to imx i2c bus so that blocks of data
can be read using SMbus block reads.(using i2c_smbus_read_block_data()
function from the i2c_core.c.). Tested with 3.10.9 kernel.

Reviewed-by: default avatarShawn Guo <shawn.guo@freescale.com>
Signed-off-by: default avatarKaushal Butala <kaushalkernelmailinglist@gmail.com>
Signed-off-by: default avatarWolfram Sang <wsa@the-dreams.de>
parent 5ed9d92f

drivers/i2c/busses/i2c-imx.c

+28 −3
Original line number Diff line number Diff line
@@ -462,6 +462,7 @@ static int i2c_imx_read(struct imx_i2c_struct *i2c_imx, struct i2c_msg *msgs) 
{

	int i, result;

	unsigned int temp;

	int block_data = msgs->flags & I2C_M_RECV_LEN;



	dev_dbg(&i2c_imx->adapter.dev,

		"<%s> write slave address: addr=0x%x\n",
@@ -481,7 +482,12 @@ static int i2c_imx_read(struct imx_i2c_struct *i2c_imx, struct i2c_msg *msgs) 
	/* setup bus to read data */

	temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);

	temp &= ~I2CR_MTX;

	if (msgs->len - 1)



	/*

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

	 * length is unknown

	 */

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

		temp &= ~I2CR_TXAK;

	imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);

	imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR); /* dummy read */
@@ -490,9 +496,24 @@ static int i2c_imx_read(struct imx_i2c_struct *i2c_imx, struct i2c_msg *msgs) 


	/* read data */

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

		u8 len = 0;

		result = i2c_imx_trx_complete(i2c_imx);

		if (result)

			return result;

		/*

		 * First byte is the length of remaining packet

		 * in the SMBus block data read. Add it to

		 * msgs->len.

		 */

		if ((!i) && block_data) {

			len = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR);

			if ((len == 0) || (len > I2C_SMBUS_BLOCK_MAX))

				return -EPROTO;

			dev_dbg(&i2c_imx->adapter.dev,

				"<%s> read length: 0x%X\n",

				__func__, len);

			msgs->len += len;

		}

		if (i == (msgs->len - 1)) {

			/* It must generate STOP before read I2DR to prevent

			   controller from generating another clock cycle */
@@ -510,6 +531,9 @@ static int i2c_imx_read(struct imx_i2c_struct *i2c_imx, struct i2c_msg *msgs) 
			temp |= I2CR_TXAK;

			imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);

		}

		if ((!i) && block_data)

			msgs->buf[0] = len;

		else

			msgs->buf[i] =  imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR);

		dev_dbg(&i2c_imx->adapter.dev,

			"<%s> read byte: B%d=0x%X\n",
@@ -583,7 +607,8 @@ fail0: 


static u32 i2c_imx_func(struct i2c_adapter *adapter)

{

	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;

	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL

		| I2C_FUNC_SMBUS_READ_BLOCK_DATA;

}



static struct i2c_algorithm i2c_imx_algo = {

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