[PATCH V1 1/3] serial: 8250_fintek: UART dynamic clocksource on Fintek F81866

From: Ji-Ze Hong (Peter Hong)
Date: Mon Oct 02 2017 - 23:10:38 EST


The F81866 had 4 clocksource 1.8432/18.432/14.769/24MHz and baud rates can
be up to 1.5Mbits with 24MHz. We'll implements the dynamic clocksource in
fintek_8250_set_termios().

Signed-off-by: Ji-Ze Hong (Peter Hong) <hpeter+linux_kernel@xxxxxxxxx>
---
drivers/tty/serial/8250/8250_fintek.c | 54 +++++++++++++++++++++++++++++++++++
1 file changed, 54 insertions(+)

diff --git a/drivers/tty/serial/8250/8250_fintek.c b/drivers/tty/serial/8250/8250_fintek.c
index e500f7d..53ea353 100644
--- a/drivers/tty/serial/8250/8250_fintek.c
+++ b/drivers/tty/serial/8250/8250_fintek.c
@@ -287,6 +287,59 @@ static void fintek_8250_goto_highspeed(struct uart_8250_port *uart,
}
}

+void fintek_8250_set_termios(struct uart_port *port, struct ktermios *termios,
+ struct ktermios *old)
+{
+ struct fintek_8250 *pdata = port->private_data;
+ unsigned int baud = tty_termios_baud_rate(termios);
+ int i;
+ static u32 baudrate_table[] = {115200, 921600, 1152000, 1500000};
+ static u8 clock_table[] = { F81866_UART_CLK_1_8432MHZ,
+ F81866_UART_CLK_14_769MHZ, F81866_UART_CLK_18_432MHZ,
+ F81866_UART_CLK_24MHZ };
+
+ for (i = 0; i < ARRAY_SIZE(baudrate_table); ++i) {
+ if (baud > baudrate_table[i] || baudrate_table[i] % baud != 0)
+ continue;
+
+ if (port->uartclk == baudrate_table[i] * 16)
+ break;
+
+ if (fintek_8250_enter_key(pdata->base_port, pdata->key))
+ continue;
+
+ port->uartclk = baudrate_table[i] * 16;
+
+ sio_write_reg(pdata, LDN, pdata->index);
+ sio_write_mask_reg(pdata, F81866_UART_CLK,
+ F81866_UART_CLK_MASK, clock_table[i]);
+
+ fintek_8250_exit_key(pdata->base_port);
+ break;
+ }
+
+ if (i == ARRAY_SIZE(baudrate_table)) {
+ baud = tty_termios_baud_rate(old);
+ tty_termios_encode_baud_rate(termios, baud, baud);
+ }
+
+ serial8250_do_set_termios(port, termios, old);
+}
+
+static void fintek_8250_set_termios_handler(struct uart_8250_port *uart)
+{
+ struct fintek_8250 *pdata = uart->port.private_data;
+
+ switch (pdata->pid) {
+ case CHIP_ID_F81866:
+ uart->port.set_termios = fintek_8250_set_termios;
+ break;
+
+ default:
+ break;
+ }
+}
+
static int probe_setup_port(struct fintek_8250 *pdata,
struct uart_8250_port *uart)
{
@@ -373,6 +426,7 @@ int fintek_8250_probe(struct uart_8250_port *uart)
memcpy(pdata, &probe_data, sizeof(probe_data));
uart->port.private_data = pdata;
fintek_8250_set_rs485_handler(uart);
+ fintek_8250_set_termios_handler(uart);

return 0;
}
--
1.9.1