Re: [PATCH] use callbacks to access UART_DLL/UART_DLM

[Sebastian Frias <sf84@laposte.net>]

On 12/17/2015 05:02 PM, Måns Rullgård wrote:
> Sebastian Frias <sf84@laposte.net> writes:
>
>> ---
>> resending as plain-text
>> ---
>>    drivers/tty/serial/8250/8250_core.c |   17 +++++++----------
>>    1 file changed, 7 insertions(+), 10 deletions(-)
>>
>> diff --git a/drivers/tty/serial/8250/8250_core.c
>> b/drivers/tty/serial/8250/8250_core.c
>> index 2c46a21..9ca863c 100644
>> --- a/drivers/tty/serial/8250/8250_core.c
>> +++ b/drivers/tty/serial/8250/8250_core.c
>> @@ -791,22 +791,19 @@ static int size_fifo(struct uart_8250_port *up)
>>     */
>>    static unsigned int autoconfig_read_divisor_id(struct uart_8250_port *p)
>
> What tree are you working against?  Current mainline has that function
> in 8250_port.c.

Sorry, wrong patch. On mainline is about the same, I'll post it.

>
>>    {
>> -    unsigned char old_dll, old_dlm, old_lcr;
>> +    unsigned char old_lcr;
>>        unsigned int id;
>> +    unsigned int old_dl;
>
> Your patch is messed up.  Consider using "git send-email" instead.

I don't know what happened there, thanks for the suggestion.

>
>>        old_lcr = serial_in(p, UART_LCR);
>> -    serial_out(p, UART_LCR, UART_LCR_CONF_MODE_A);
>> -
>> -    old_dll = serial_in(p, UART_DLL);
>> -    old_dlm = serial_in(p, UART_DLM);
>>
>> -    serial_out(p, UART_DLL, 0);
>> -    serial_out(p, UART_DLM, 0);
>> +    serial_out(p, UART_LCR, UART_LCR_CONF_MODE_A);
>>
>> -    id = serial_in(p, UART_DLL) | serial_in(p, UART_DLM) << 8;
>> +    old_dl = serial_dl_read(p);
>> +    serial_dl_write(p, 0);
>> +    id = serial_dl_read(p);
>> +    serial_dl_write(p, old_dl);
>>
>> -    serial_out(p, UART_DLL, old_dll);
>> -    serial_out(p, UART_DLM, old_dlm);
>>        serial_out(p, UART_LCR, old_lcr);
>>
>>        return id;
>> --
>
> If you left the blank lines alone, the patch would end up much easier to
> understand.  In this diff, some of the lines listed as added or removed
> have actually not changed, and that's not immediately obvious.
>

The old code had some blank lines, which I suppose were there for clarity.
I attempted to follow the same idea.
But I don't mind changing the code as you wish.