The baudrate derivation relies on the state of the programmable over
sampling stack (OSAMP register) being empty, while never initializing
it.
Set all the fields of this register to 0 (except reserved areas) to
ensure a x16 divisor, as assumed by the driver.
The suspend/resume callbacks are untouched because they already
save/restore correctly this register.
Suggested-by: Thomas Petazzoni <thomas.petazzoni@xxxxxxxxxxx>
Signed-off-by: Miquel Raynal <miquel.raynal@xxxxxxxxxxx>
---
drivers/tty/serial/mvebu-uart.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/tty/serial/mvebu-uart.c b/drivers/tty/serial/mvebu-uart.c
index df6e4d8cdbd6..231f751d1ef4 100644
--- a/drivers/tty/serial/mvebu-uart.c
+++ b/drivers/tty/serial/mvebu-uart.c
@@ -73,6 +73,7 @@
#define UART_OSAMP 0x14
#define OSAMP_DEFAULT_DIVISOR 16
+#define OSAMP_DIVISORS_MASK 0x3F3F3F3F
#define MVEBU_NR_UARTS 2
@@ -446,7 +447,7 @@ static int mvebu_uart_baud_rate_set(struct uart_port *port, unsigned int baud)
{
struct mvebu_uart *mvuart = to_mvuart(port);
unsigned int d_divisor, m_divisor;
- u32 brdv;
+ u32 brdv, osamp;
if (IS_ERR(mvuart->clk))
return -PTR_ERR(mvuart->clk);
@@ -469,6 +470,10 @@ static int mvebu_uart_baud_rate_set(struct uart_port *port, unsigned int baud)
brdv |= d_divisor;
writel(brdv, port->membase + UART_BRDV);
+ osamp = readl(port->membase + UART_OSAMP);
+ osamp &= ~OSAMP_DIVISORS_MASK;
+ writel(osamp, port->membase + UART_OSAMP);
+
return 0;
}
--
2.19.1
