--- /dev/null...
+++ b/drivers/tty/serial/si4455.c
@@ -0,0 +1,1372 @@
+static int si4455_write_data(struct uart_port *port, u8 command, int poll,
+ int length, const u8 *data)
+{
+ int ret = 0;
+ u8 *data_out;
+
+ if (poll) {
+ ret = si4455_poll_cts(port);
+ if (ret)
+ return ret;
+ }
+
+ data_out = kzalloc(1 + length, GFP_KERNEL);
+ if (!data_out)
+ return -ENOMEM;
+
+ data_out[0] = command;
+ memcpy(&data_out[1], data, length);
+ ret = spi_write(to_spi_device(port->dev), data_out, 1 + length);
+ if (ret) {
+ dev_err(port->dev,
+ "%s: spi_write error (%i)\n", __func__, ret);
+ }
+
+ kfree(data_out);
+
+ return ret;
+}
+
+static void si4455_set_power(struct si4455_port *priv, int on)
+{
+ if (!priv->shdn_gpio)
+ return;
+ if (on) {
+ gpiod_direction_output(priv->shdn_gpio, 0);
+ usleep_range(4000, 5000);
+ gpiod_set_value(priv->shdn_gpio, 1);
+ usleep_range(4000, 5000);
+ } else {
+ gpiod_direction_output(priv->shdn_gpio, 0);
+ }
+static void si4455_handle_rx_pend(struct si4455_port *s)
+{
+ struct uart_port *port = &s->port;
+ u8 *data = NULL;
+ int sret = 0;
+ int i = 0;
+
+ if (s->package_size == 0) {
+ //TODO: variable packet length
+ dev_err(port->dev, "%s: variable packet length is not supported by the driver\n",
+ __func__);
+ return;
+ }
+
+ data = kzalloc(s->package_size, GFP_KERNEL);
+ sret = si4455_end_rx(port, s->package_size, data);...
+ if (sret) {
+ dev_err(port->dev, "%s: si4455_end_rx error (%i)\n",
+ __func__, sret);
+ } else {
+ for (i = 0; i < s->package_size; i++) {
+ uart_insert_char(port, 0, 0, data[i], TTY_NORMAL);
+ port->icount.rx++;
+ }
+ tty_flip_buffer_push(&port->state->port);
+ }
+ kfree(data);
+}