Re: [PATCH v5 3/3] tty: serial: qcom_geni_serial: Remove sysfs file

[Akash Asthana <akashast@codeaurora.org>]

On 11/14/2019 11:06 PM, Stephen Boyd wrote:
> Please update the subject. This patch does more than remove the sysfs
> file. "Move loopback support to TIOCM_LOOP"?
Ok, I will update this in next version.
> Quoting Akash Asthana (2019-11-13 02:49:21)
>> Remove code from the driver that create and maintain loopback sysfs node.
>> Instead use the ioctl TIOCMSET with TIOCM_LOOP argument to set HW to
>> loopback mode.
>>
>> Signed-off-by: Akash Asthana <akashast@codeaurora.org>
>> ---
>> Changes in V5:
>>   - As per Greg's and Stephen's comment on v4 patch, removed loopback sysfs
>>     file related code.
>>
>>   drivers/tty/serial/qcom_geni_serial.c | 30 ++++--------------------------
>>   1 file changed, 4 insertions(+), 26 deletions(-)
>>
>> diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c
>> index 56dad67..52f5ea2 100644
>> --- a/drivers/tty/serial/qcom_geni_serial.c
>> +++ b/drivers/tty/serial/qcom_geni_serial.c
>> @@ -238,10 +214,14 @@ static void qcom_geni_serial_set_mctrl(struct uart_port *uport,
>>                                                          unsigned int mctrl)
>>   {
>>          u32 uart_manual_rfr = 0;
>> +       struct qcom_geni_serial_port *port = to_dev_port(uport, uport);
>>   
>>          if (uart_console(uport))
>>                  return;
>>   
>> +       if (mctrl & TIOCM_LOOP)
>> +               port->loopback = MAX_LOOPBACK_CFG;
> How does this work? The loopback is supposed to be the max all the time
> and not match some qup number or something?
port->loopback is unrelated to QUP number. However we have different 
modes to run loopback test, 1(rx-tx sorted), 2(cts-rts sorted),

3 or Max(rx-tx sorted and cts-rts sorted). In our internal testing we 
only use mode 3 hence we are initializing port->loopback variable

to 3 and eventually it will be written to HW register from set_termios 
call.

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