To avoid spurious chars, BRR register must only be written when USART is disabled.
Signed-off-by: Patrice Chotard patrice.chotard@foss.st.com ---
drivers/serial/serial_stm32.c | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/drivers/serial/serial_stm32.c b/drivers/serial/serial_stm32.c index 93f70947eec..0085113f674 100644 --- a/drivers/serial/serial_stm32.c +++ b/drivers/serial/serial_stm32.c @@ -29,6 +29,10 @@ static void _stm32_serial_setbrg(fdt_addr_t base, { bool stm32f4 = uart_info->stm32f4; u32 int_div, mantissa, fraction, oversampling; + u8 uart_enable_bit = uart_info->uart_enable_bit; + + /* BRR register must be set when uart is disabled */ + clrbits_le32(base + CR1_OFFSET(stm32f4), BIT(uart_enable_bit));
int_div = DIV_ROUND_CLOSEST(clock_rate, baudrate);
@@ -44,6 +48,8 @@ static void _stm32_serial_setbrg(fdt_addr_t base, fraction = int_div % oversampling;
writel(mantissa | fraction, base + BRR_OFFSET(stm32f4)); + + setbits_le32(base + CR1_OFFSET(stm32f4), BIT(uart_enable_bit)); }
static int stm32_serial_setbrg(struct udevice *dev, int baudrate)