[PATCH V6 4/5] tty: serial: meson: Make some bit of the REG5 register writable

[Yu Tu]

Hi Jerome,
	Thank you very much for your reply. At present, the problem of 
switching uART baud rate stuck has been solved. I'm ready to send the 
next edition.

On 2022/1/21 5:49, Jerome Brunet wrote:
> [ EXTERNAL EMAIL ]
> 
> 
> On Tue 18 Jan 2022 at 11:09, Yu Tu <yu.tu at amlogic.com> wrote:
> 
>> The UART_REG5 register defaults to 0. The console port is set in
>> ROMCODE. But other UART ports default to 0, so make bit24 and
>> bit[26,27] writable so that the UART can choose a more
>> appropriate clock.
> 
> Suggestion: Instead of talking bits (which is a bit cryptic) tell us
> what is actually does
> 
> Something like:
>   Make the internal clock source mux and divider writeable, allowing the
>   uart to deviate from the settings intially applied by the ROMCode and
>   using the most appropriate clocks
> 
Your description is better, I will follow your suggestion in the next 
edition.
>>
>> Signed-off-by: Yu Tu <yu.tu at amlogic.com>
>> ---
>>   drivers/tty/serial/meson_uart.c | 4 ++--
>>   1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/tty/serial/meson_uart.c b/drivers/tty/serial/meson_uart.c
>> index 92fa91c825e6..4e7b2b38ab0a 100644
>> --- a/drivers/tty/serial/meson_uart.c
>> +++ b/drivers/tty/serial/meson_uart.c
>> @@ -678,7 +678,7 @@ static int meson_uart_probe_clocks(struct uart_port *port)
>>   							CLK_SET_RATE_NO_REPARENT,
>>   							port->membase + AML_UART_REG5,
>>   							26, 2,
>> -							CLK_DIVIDER_READ_ONLY,
>> +							CLK_DIVIDER_ROUND_CLOSEST,
>>   							xtal_div_table, NULL);
>>   		if (IS_ERR(hw))
>>   			return PTR_ERR(hw);
>> @@ -708,7 +708,7 @@ static int meson_uart_probe_clocks(struct uart_port *port)
>>   					CLK_SET_RATE_PARENT,
>>   					port->membase + AML_UART_REG5,
>>   					24, 0x1,
>> -					CLK_MUX_READ_ONLY,
>> +					CLK_MUX_ROUND_CLOSEST,
>>   					NULL, NULL);
>>   	if (IS_ERR(hw))
>>   		return PTR_ERR(hw);
>