* [PATCH 1/2] serial: 8250_pci: more BayTrail error-free bauds
[not found] <263958445.81234.1393897872966.JavaMail.zimbra@xes-inc.com>
@ 2014-03-04 1:54 ` Aaron Sierra
2014-03-04 14:54 ` 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
Support the following additional baud rates with 0% error:
500000, 1500000, 2500000, 3500000
Signed-off-by: Aaron Sierra <asierra@xes-inc.com>
---
drivers/tty/serial/8250/8250_pci.c | 37 ++++++++++++++++++++++++++++--------
1 file changed, 29 insertions(+), 8 deletions(-)
diff --git a/drivers/tty/serial/8250/8250_pci.c b/drivers/tty/serial/8250/8250_pci.c
index 50228ee..e4289b2 100644
--- a/drivers/tty/serial/8250/8250_pci.c
+++ b/drivers/tty/serial/8250/8250_pci.c
@@ -1365,22 +1365,43 @@ byt_set_termios(struct uart_port *p, struct ktermios *termios,
struct ktermios *old)
{
unsigned int baud = tty_termios_baud_rate(termios);
- unsigned int m = 6912;
- unsigned int n = 15625;
+ unsigned int m, n;
u32 reg;
- /* For baud rates 1M, 2M, 3M and 4M the dividers must be adjusted. */
- if (baud == 1000000 || baud == 2000000 || baud == 4000000) {
+ /*
+ * For baud rates 0.5M, 1M, 1.5M, 2M, 2.5M, 3M, 3.5M and 4M the
+ * dividers must be adjusted.
+ *
+ * uartclk = (m / n) * 100 MHz, where m <= n
+ */
+ switch (baud) {
+ case 500000:
+ case 1000000:
+ case 2000000:
+ case 4000000:
m = 64;
n = 100;
-
p->uartclk = 64000000;
- } else if (baud == 3000000) {
+ break;
+ case 3500000:
+ m = 56;
+ n = 100;
+ p->uartclk = 56000000;
+ break;
+ case 1500000:
+ case 3000000:
m = 48;
n = 100;
-
p->uartclk = 48000000;
- } else {
+ break;
+ case 2500000:
+ m = 40;
+ n = 100;
+ p->uartclk = 40000000;
+ break;
+ default:
+ m = 6912;
+ n = 15625;
p->uartclk = 44236800;
}
--
1.7.9.5
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