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

[Stephen Boyd <swboyd@chromium.org>]

Quoting Akash Asthana (2019-11-15 01:57:48)
> 
> 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.

Ok. Thanks for clarifying. Can you rename this macro to
RX_TX_CTS_RTS_SORTED? I imagine seeing something like:

	/* SE_UART_LOOPBACK_CFG */
	#define RX_TX_SORTED		BIT(0)
	#define CTS_RTS_SORTED		BIT(1)
	#define RX_TX_CTS_RTS_SORTED	RX_TX_SORTED | CTS_RTS_SORTED

or whatever the bit field names really are.