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Commit 504b8277 authored by Eddie James's avatar Eddie James Committed by Wolfram Sang
Browse files

i2c: fsi: Add transfer implementation 



Execute I2C transfers from the FSI-attached I2C master. Use polling
instead of interrupts as we have no hardware IRQ over FSI.

Signed-off-by: default avatarEddie James <eajames@linux.vnet.ibm.com>
Reviewed-by: default avatarAndy Shevchenko <andy.shevchenko@gmail.com>
Tested-by: default avatarJoel Stanley <joel@jms.id.au>
Signed-off-by: default avatarWolfram Sang <wsa@the-dreams.de>
parent 6cdf5e39

drivers/i2c/busses/i2c-fsi.c

+193 −2
Original line number Diff line number Diff line
@@ -155,6 +155,7 @@ struct fsi_i2c_port { 
	struct i2c_adapter	adapter;

	struct fsi_i2c_master	*master;

	u16			port;

	u16			xfrd;

};



static int fsi_i2c_read_reg(struct fsi_device *fsi, unsigned int reg,
@@ -230,6 +231,99 @@ static int fsi_i2c_set_port(struct fsi_i2c_port *port) 
	return fsi_i2c_write_reg(fsi, I2C_FSI_RESET_ERR, &dummy);

}



static int fsi_i2c_start(struct fsi_i2c_port *port, struct i2c_msg *msg,

			 bool stop)

{

	struct fsi_i2c_master *i2c = port->master;

	u32 cmd = I2C_CMD_WITH_START | I2C_CMD_WITH_ADDR;



	port->xfrd = 0;



	if (msg->flags & I2C_M_RD)

		cmd |= I2C_CMD_READ;



	if (stop || msg->flags & I2C_M_STOP)

		cmd |= I2C_CMD_WITH_STOP;



	cmd |= FIELD_PREP(I2C_CMD_ADDR, msg->addr);

	cmd |= FIELD_PREP(I2C_CMD_LEN, msg->len);



	return fsi_i2c_write_reg(i2c->fsi, I2C_FSI_CMD, &cmd);

}



static int fsi_i2c_get_op_bytes(int op_bytes)

{

	/* fsi is limited to max 4 byte aligned ops */

	if (op_bytes > 4)

		return 4;

	else if (op_bytes == 3)

		return 2;

	return op_bytes;

}



static int fsi_i2c_write_fifo(struct fsi_i2c_port *port, struct i2c_msg *msg,

			      u8 fifo_count)

{

	int write;

	int rc;

	struct fsi_i2c_master *i2c = port->master;

	int bytes_to_write = i2c->fifo_size - fifo_count;

	int bytes_remaining = msg->len - port->xfrd;



	bytes_to_write = min(bytes_to_write, bytes_remaining);



	while (bytes_to_write) {

		write = fsi_i2c_get_op_bytes(bytes_to_write);



		rc = fsi_device_write(i2c->fsi, I2C_FSI_FIFO,

				      &msg->buf[port->xfrd], write);

		if (rc)

			return rc;



		port->xfrd += write;

		bytes_to_write -= write;

	}



	return 0;

}



static int fsi_i2c_read_fifo(struct fsi_i2c_port *port, struct i2c_msg *msg,

			     u8 fifo_count)

{

	int read;

	int rc;

	struct fsi_i2c_master *i2c = port->master;

	int bytes_to_read;

	int xfr_remaining = msg->len - port->xfrd;

	u32 dummy;



	bytes_to_read = min_t(int, fifo_count, xfr_remaining);



	while (bytes_to_read) {

		read = fsi_i2c_get_op_bytes(bytes_to_read);



		if (xfr_remaining) {

			rc = fsi_device_read(i2c->fsi, I2C_FSI_FIFO,

					     &msg->buf[port->xfrd], read);

			if (rc)

				return rc;



			port->xfrd += read;

			xfr_remaining -= read;

		} else {

			/* no more buffer but data in fifo, need to clear it */

			rc = fsi_device_read(i2c->fsi, I2C_FSI_FIFO, &dummy,

					     read);

			if (rc)

				return rc;

		}



		bytes_to_read -= read;

	}



	return 0;

}



static int fsi_i2c_reset_engine(struct fsi_i2c_master *i2c, u16 port)

{

	int rc;
@@ -305,17 +399,114 @@ static int fsi_i2c_abort(struct fsi_i2c_port *port, u32 status) 
	return -ETIMEDOUT;

}



static int fsi_i2c_handle_status(struct fsi_i2c_port *port,

				 struct i2c_msg *msg, u32 status)

{

	int rc;

	u8 fifo_count;



	if (status & I2C_STAT_ERR) {

		rc = fsi_i2c_abort(port, status);

		if (rc)

			return rc;



		if (status & I2C_STAT_INV_CMD)

			return -EINVAL;



		if (status & (I2C_STAT_PARITY | I2C_STAT_BE_OVERRUN |

		    I2C_STAT_BE_ACCESS))

			return -EPROTO;



		if (status & I2C_STAT_NACK)

			return -ENXIO;



		if (status & I2C_STAT_LOST_ARB)

			return -EAGAIN;



		if (status & I2C_STAT_STOP_ERR)

			return -EBADMSG;



		return -EIO;

	}



	if (status & I2C_STAT_DAT_REQ) {

		fifo_count = FIELD_GET(I2C_STAT_FIFO_COUNT, status);



		if (msg->flags & I2C_M_RD)

			return fsi_i2c_read_fifo(port, msg, fifo_count);



		return fsi_i2c_write_fifo(port, msg, fifo_count);

	}



	if (status & I2C_STAT_CMD_COMP) {

		if (port->xfrd < msg->len)

			return -ENODATA;



		return msg->len;

	}



	return 0;

}



static int fsi_i2c_wait(struct fsi_i2c_port *port, struct i2c_msg *msg,

			unsigned long timeout)

{

	u32 status = 0;

	int rc;

	unsigned long start = jiffies;



	do {

		rc = fsi_i2c_read_reg(port->master->fsi, I2C_FSI_STAT,

				      &status);

		if (rc)

			return rc;



		if (status & I2C_STAT_ANY_RESP) {

			rc = fsi_i2c_handle_status(port, msg, status);

			if (rc < 0)

				return rc;



			/* cmd complete and all data xfrd */

			if (rc == msg->len)

				return 0;



			/* need to xfr more data, but maybe don't need wait */

			continue;

		}



		usleep_range(I2C_CMD_SLEEP_MIN_US, I2C_CMD_SLEEP_MAX_US);

	} while (time_after(start + timeout, jiffies));



	return -ETIMEDOUT;

}



static int fsi_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,

			int num)

{

	int rc;

	int i, rc;

	unsigned long start_time;

	struct fsi_i2c_port *port = adap->algo_data;

	struct i2c_msg *msg;



	rc = fsi_i2c_set_port(port);

	if (rc)

		return rc;



	return -EOPNOTSUPP;

	for (i = 0; i < num; i++) {

		msg = msgs + i;

		start_time = jiffies;



		rc = fsi_i2c_start(port, msg, i == num - 1);

		if (rc)

			return rc;



		rc = fsi_i2c_wait(port, msg,

				  adap->timeout - (jiffies - start_time));

		if (rc)

			return rc;

	}



	return num;

}



static u32 fsi_i2c_functionality(struct i2c_adapter *adap)