On 07.09.2022 12:23, Ilpo Järvinen wrote:
> 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?
Yes, it would seem that would be right. It did not cross my mind to
check whether there already was something pre-defined or not since the
code also previously used 65535.
>
>> }
>> +
>> quot = cd | fp << ATMEL_US_FP_OFFSET;
>>
>> if (!(port->iso7816.flags & SER_ISO7816_ENABLED))
>>
>
> --
> i.
>
Thanks,
Sergiu
