* [PATCH 2/2] serial: 8250_pci: change BayTrail default uartclk
[not found] <694295964.81260.1393897982162.JavaMail.zimbra@xes-inc.com>
@ 2014-03-04 1:54 ` Aaron Sierra
2014-03-04 14:55 ` Heikki Krogerus
0 siblings, 1 reply; 2+ messages in thread
From: Aaron Sierra @ 2014-03-04 1:54 UTC (permalink / raw)
To: linux-serial; +Cc: Greg Kroah-Hartman, Heikki Krogerus
The Intel BayTrail HSUART power-on default reference clock is 44.2368 MHz,
but 73.728 MHz provides 0% error for additional "conventional" baud rates
above 460800 (e.g. 576000, 921600, and 1152000).
Signed-off-by: Aaron Sierra <asierra@xes-inc.com>
---
drivers/tty/serial/8250/8250_pci.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/drivers/tty/serial/8250/8250_pci.c b/drivers/tty/serial/8250/8250_pci.c
index e4289b2..75398af 100644
--- a/drivers/tty/serial/8250/8250_pci.c
+++ b/drivers/tty/serial/8250/8250_pci.c
@@ -1400,9 +1400,9 @@ byt_set_termios(struct uart_port *p, struct ktermios *termios,
p->uartclk = 40000000;
break;
default:
- m = 6912;
- n = 15625;
- p->uartclk = 44236800;
+ m = 2304;
+ n = 3125;
+ p->uartclk = 73728000;
}
/* Reset the clock */
@@ -3469,6 +3469,10 @@ static struct pciserial_board pci_boards[] = {
.base_baud = 921600,
.reg_shift = 2,
},
+ /*
+ * Intel BayTrail HSUART reference clock is 44.2368 MHz at power-on,
+ * but is overridden by byt_set_termios.
+ */
[pbn_byt] = {
.flags = FL_BASE0,
.num_ports = 1,
--
1.7.9.5
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