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: Eddie James <eajames@linux.vnet.ibm.com> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Tested-by: Joel Stanley <joel@jms.id.au> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>hifive-unleashed-5.1
Eddie James
Wolfram Sang
parent
6cdf5e397a
commit
504b82773c
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@ -155,6 +155,7 @@ struct fsi_i2c_port {
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struct i2c_adapter adapter;
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struct fsi_i2c_master *master;
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u16 port;
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u16 xfrd;
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};
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static int fsi_i2c_read_reg(struct fsi_device *fsi, unsigned int reg,
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@ -230,6 +231,99 @@ static int fsi_i2c_set_port(struct fsi_i2c_port *port)
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return fsi_i2c_write_reg(fsi, I2C_FSI_RESET_ERR, &dummy);
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}
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static int fsi_i2c_start(struct fsi_i2c_port *port, struct i2c_msg *msg,
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bool stop)
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{
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struct fsi_i2c_master *i2c = port->master;
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u32 cmd = I2C_CMD_WITH_START | I2C_CMD_WITH_ADDR;
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port->xfrd = 0;
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if (msg->flags & I2C_M_RD)
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cmd |= I2C_CMD_READ;
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if (stop || msg->flags & I2C_M_STOP)
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cmd |= I2C_CMD_WITH_STOP;
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cmd |= FIELD_PREP(I2C_CMD_ADDR, msg->addr);
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cmd |= FIELD_PREP(I2C_CMD_LEN, msg->len);
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return fsi_i2c_write_reg(i2c->fsi, I2C_FSI_CMD, &cmd);
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}
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static int fsi_i2c_get_op_bytes(int op_bytes)
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{
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/* fsi is limited to max 4 byte aligned ops */
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if (op_bytes > 4)
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return 4;
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else if (op_bytes == 3)
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return 2;
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return op_bytes;
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}
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static int fsi_i2c_write_fifo(struct fsi_i2c_port *port, struct i2c_msg *msg,
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u8 fifo_count)
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{
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int write;
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int rc;
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struct fsi_i2c_master *i2c = port->master;
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int bytes_to_write = i2c->fifo_size - fifo_count;
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int bytes_remaining = msg->len - port->xfrd;
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bytes_to_write = min(bytes_to_write, bytes_remaining);
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while (bytes_to_write) {
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write = fsi_i2c_get_op_bytes(bytes_to_write);
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rc = fsi_device_write(i2c->fsi, I2C_FSI_FIFO,
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&msg->buf[port->xfrd], write);
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if (rc)
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return rc;
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port->xfrd += write;
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bytes_to_write -= write;
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}
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return 0;
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}
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static int fsi_i2c_read_fifo(struct fsi_i2c_port *port, struct i2c_msg *msg,
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u8 fifo_count)
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{
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int read;
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int rc;
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struct fsi_i2c_master *i2c = port->master;
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int bytes_to_read;
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int xfr_remaining = msg->len - port->xfrd;
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u32 dummy;
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bytes_to_read = min_t(int, fifo_count, xfr_remaining);
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while (bytes_to_read) {
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read = fsi_i2c_get_op_bytes(bytes_to_read);
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if (xfr_remaining) {
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rc = fsi_device_read(i2c->fsi, I2C_FSI_FIFO,
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&msg->buf[port->xfrd], read);
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if (rc)
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return rc;
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port->xfrd += read;
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xfr_remaining -= read;
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} else {
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/* no more buffer but data in fifo, need to clear it */
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rc = fsi_device_read(i2c->fsi, I2C_FSI_FIFO, &dummy,
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read);
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if (rc)
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return rc;
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}
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bytes_to_read -= read;
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}
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return 0;
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}
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static int fsi_i2c_reset_engine(struct fsi_i2c_master *i2c, u16 port)
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{
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int rc;
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@ -305,17 +399,114 @@ static int fsi_i2c_abort(struct fsi_i2c_port *port, u32 status)
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return -ETIMEDOUT;
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}
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static int fsi_i2c_handle_status(struct fsi_i2c_port *port,
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struct i2c_msg *msg, u32 status)
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{
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int rc;
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u8 fifo_count;
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if (status & I2C_STAT_ERR) {
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rc = fsi_i2c_abort(port, status);
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if (rc)
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return rc;
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if (status & I2C_STAT_INV_CMD)
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return -EINVAL;
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if (status & (I2C_STAT_PARITY | I2C_STAT_BE_OVERRUN |
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I2C_STAT_BE_ACCESS))
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return -EPROTO;
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if (status & I2C_STAT_NACK)
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return -ENXIO;
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if (status & I2C_STAT_LOST_ARB)
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return -EAGAIN;
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if (status & I2C_STAT_STOP_ERR)
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return -EBADMSG;
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return -EIO;
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}
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if (status & I2C_STAT_DAT_REQ) {
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fifo_count = FIELD_GET(I2C_STAT_FIFO_COUNT, status);
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if (msg->flags & I2C_M_RD)
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return fsi_i2c_read_fifo(port, msg, fifo_count);
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return fsi_i2c_write_fifo(port, msg, fifo_count);
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}
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if (status & I2C_STAT_CMD_COMP) {
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if (port->xfrd < msg->len)
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return -ENODATA;
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return msg->len;
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}
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return 0;
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}
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static int fsi_i2c_wait(struct fsi_i2c_port *port, struct i2c_msg *msg,
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unsigned long timeout)
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{
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u32 status = 0;
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int rc;
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unsigned long start = jiffies;
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do {
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rc = fsi_i2c_read_reg(port->master->fsi, I2C_FSI_STAT,
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&status);
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if (rc)
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return rc;
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if (status & I2C_STAT_ANY_RESP) {
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rc = fsi_i2c_handle_status(port, msg, status);
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if (rc < 0)
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return rc;
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/* cmd complete and all data xfrd */
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if (rc == msg->len)
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return 0;
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/* need to xfr more data, but maybe don't need wait */
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continue;
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}
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usleep_range(I2C_CMD_SLEEP_MIN_US, I2C_CMD_SLEEP_MAX_US);
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} while (time_after(start + timeout, jiffies));
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return -ETIMEDOUT;
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}
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static int fsi_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
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int num)
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{
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int rc;
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int i, rc;
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unsigned long start_time;
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struct fsi_i2c_port *port = adap->algo_data;
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struct i2c_msg *msg;
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rc = fsi_i2c_set_port(port);
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if (rc)
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return rc;
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return -EOPNOTSUPP;
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for (i = 0; i < num; i++) {
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msg = msgs + i;
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start_time = jiffies;
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rc = fsi_i2c_start(port, msg, i == num - 1);
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if (rc)
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return rc;
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rc = fsi_i2c_wait(port, msg,
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adap->timeout - (jiffies - start_time));
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if (rc)
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return rc;
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}
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return num;
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}
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static u32 fsi_i2c_functionality(struct i2c_adapter *adap)
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