On Tue, 6 Sep 2022, Sergiu Moga wrote:
> Make sure that the driver only divides the clock divisor if the
> IP handled at that point is USART, since UART IP's do not support
> implicit peripheral clock division. Instead, in the case of UART,
> go with the highest possible clock divisor.
>
> Signed-off-by: Sergiu Moga <sergiu.moga@xxxxxxxxxxxxx>
> ---
>
>
> v1 -> v2:
> - Nothing, this patch was not here before and is mainly meant as both cleanup
> and as a way to introduce a new field into struct atmel_uart_port that will be
> used by the last patch to diferentiate between USART and UART regarding the
> location of the Baudrate Clock Source bitmask.
>
>
>
>
> drivers/tty/serial/atmel_serial.c | 13 ++++++++++++-
> 1 file changed, 12 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
> index 7450d3853031..6aa01ca5489c 100644
> --- a/drivers/tty/serial/atmel_serial.c
> +++ b/drivers/tty/serial/atmel_serial.c
> @@ -150,6 +150,7 @@ struct atmel_uart_port {
> u32 rts_low;
> bool ms_irq_enabled;
> u32 rtor; /* address of receiver timeout register if it exists */
> + bool is_usart;
> bool has_frac_baudrate;
> bool has_hw_timer;
> struct timer_list uart_timer;
> @@ -1825,6 +1826,7 @@ static void atmel_get_ip_name(struct uart_port *port)
> */
> atmel_port->has_frac_baudrate = false;
> atmel_port->has_hw_timer = false;
> + atmel_port->is_usart = false;
>
> if (name == new_uart) {
> dev_dbg(port->dev, "Uart with hw timer");
> @@ -1834,6 +1836,7 @@ static void atmel_get_ip_name(struct uart_port *port)
> dev_dbg(port->dev, "Usart\n");
> atmel_port->has_frac_baudrate = true;
> atmel_port->has_hw_timer = true;
> + atmel_port->is_usart = true;
> atmel_port->rtor = ATMEL_US_RTOR;
> version = atmel_uart_readl(port, ATMEL_US_VERSION);
> switch (version) {
> @@ -1863,6 +1866,7 @@ static void atmel_get_ip_name(struct uart_port *port)
> dev_dbg(port->dev, "This version is usart\n");
> atmel_port->has_frac_baudrate = true;
> atmel_port->has_hw_timer = true;
> + atmel_port->is_usart = true;
> atmel_port->rtor = ATMEL_US_RTOR;
> break;
> case 0x203:
> @@ -2282,10 +2286,17 @@ static void atmel_set_termios(struct uart_port *port, struct ktermios *termios,
> cd = uart_get_divisor(port, baud);
> }
>
> - if (cd > 65535) { /* BRGR is 16-bit, so switch to slower clock */
> + /*
> + * BRGR is 16-bit, so switch to slower clock.
> + * Otherwise, keep the highest possible value for the clock divisor.
> + */
> + if (atmel_port->is_usart && cd > 65535) {
Should this be cd > ATMEL_US_CD ?
> cd /= 8;
> mode |= ATMEL_US_USCLKS_MCK_DIV8;
> + } else {
> + cd &= 65535;
ATMEL_US_CD?
> }
> +
> quot = cd | fp << ATMEL_US_FP_OFFSET;
>
> if (!(port->iso7816.flags & SER_ISO7816_ENABLED))
>
--
i.
