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path: root/drivers/tty/serial/8250/8250_pci.c
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Diffstat (limited to 'drivers/tty/serial/8250/8250_pci.c')
-rw-r--r--drivers/tty/serial/8250/8250_pci.c43
1 files changed, 34 insertions, 9 deletions
diff --git a/drivers/tty/serial/8250/8250_pci.c b/drivers/tty/serial/8250/8250_pci.c
index 0ff3e3624d4..b14bcba96c2 100644
--- a/drivers/tty/serial/8250/8250_pci.c
+++ b/drivers/tty/serial/8250/8250_pci.c
@@ -1366,23 +1366,44 @@ 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 {
- p->uartclk = 44236800;
+ break;
+ case 2500000:
+ m = 40;
+ n = 100;
+ p->uartclk = 40000000;
+ break;
+ default:
+ m = 2304;
+ n = 3125;
+ p->uartclk = 73728000;
}
/* Reset the clock */
@@ -3449,6 +3470,10 @@ 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,