diff options
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/tty/serial/max310x.c | 36 |
1 files changed, 29 insertions, 7 deletions
diff --git a/drivers/tty/serial/max310x.c b/drivers/tty/serial/max310x.c index 9e4e70f864ea..2a2c4ea16306 100644 --- a/drivers/tty/serial/max310x.c +++ b/drivers/tty/serial/max310x.c @@ -233,6 +233,7 @@ /* Misc definitions */ #define MAX310X_FIFO_SIZE (128) #define MAX310x_REV_MASK (0xf8) +#define MAX310X_WRITE_BIT 0x80 /* MAX3107 specific */ #define MAX3107_REV_ID (0xa0) @@ -593,6 +594,21 @@ static int max310x_set_ref_clk(struct max310x_port *s, unsigned long freq, return (int)bestfreq; } +static void max310x_batch_write(struct uart_port *port, u8 *txbuf, unsigned int len) +{ + u8 header[] = { (port->iobase + MAX310X_THR_REG) | MAX310X_WRITE_BIT }; + struct spi_transfer xfer[] = { + { + .tx_buf = &header, + .len = sizeof(header), + }, { + .tx_buf = txbuf, + .len = len, + } + }; + spi_sync_transfer(to_spi_device(port->dev), xfer, ARRAY_SIZE(xfer)); +} + static void max310x_handle_rx(struct uart_port *port, unsigned int rxlen) { unsigned int sts, ch, flag; @@ -652,7 +668,7 @@ static void max310x_handle_rx(struct uart_port *port, unsigned int rxlen) static void max310x_handle_tx(struct uart_port *port) { struct circ_buf *xmit = &port->state->xmit; - unsigned int txlen, to_send; + unsigned int txlen, to_send, until_end; if (unlikely(port->x_char)) { max310x_port_write(port, MAX310X_THR_REG, port->x_char); @@ -666,19 +682,25 @@ static void max310x_handle_tx(struct uart_port *port) /* Get length of data pending in circular buffer */ to_send = uart_circ_chars_pending(xmit); + until_end = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE); if (likely(to_send)) { /* Limit to size of TX FIFO */ txlen = max310x_port_read(port, MAX310X_TXFIFOLVL_REG); txlen = port->fifosize - txlen; to_send = (to_send > txlen) ? txlen : to_send; + if (until_end < to_send) { + /* It's a circ buffer -- wrap around. + * We could do that in one SPI transaction, but meh. */ + max310x_batch_write(port, xmit->buf + xmit->tail, until_end); + max310x_batch_write(port, xmit->buf, to_send - until_end); + } else { + max310x_batch_write(port, xmit->buf + xmit->tail, to_send); + } + /* Add data to send */ port->icount.tx += to_send; - while (to_send--) { - max310x_port_write(port, MAX310X_THR_REG, - xmit->buf[xmit->tail]); - xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1); - } + xmit->tail = (xmit->tail + to_send) & (UART_XMIT_SIZE - 1); } if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) @@ -1301,7 +1323,7 @@ MODULE_DEVICE_TABLE(of, max310x_dt_ids); static struct regmap_config regcfg = { .reg_bits = 8, .val_bits = 8, - .write_flag_mask = 0x80, + .write_flag_mask = MAX310X_WRITE_BIT, .cache_type = REGCACHE_RBTREE, .writeable_reg = max310x_reg_writeable, .volatile_reg = max310x_reg_volatile, |