[PATCH 2/7] serial_msm: Add support for RS232 GPIOs

[Sumit Garg]

On Tue, 19 Dec 2023 at 22:17, Caleb Connolly <caleb.connolly at linaro.org> wrote:
>
> I guess these GPIOs are RTS/CTS? Missing description...

No, these GPIOs (99 and 100) on HMIBSC board rather act as a mux to
control UART mode out of rs232/422/485. I will add a corresponding
description.

>
> Given that you just set them to their respective values, you should be
> able to configure these using pinctrl with this patch [1], so we can
> avoid adding these non-standard bindings.

Okay I will try to use them once we resolve the conflicts discussed in
the other thread.

>
> I tested your next patch, setting "MSM_UART_MR1_RX_RDY_CTL" in
> uart_dm_init() on db410c and db820c and I don't notice any issues with
> setting that bit unconditionally. If it's definitely needed for your
> board then I'd be ok with a patch to always set it with a comment
> offering some context.

Yeah it's needed for RS232 mode to operate correctly. I will make it
unconditional then.

-Sumit

>
> [1]:
> https://lore.kernel.org/u-boot/20231219-b4-qcom-common-target-v2-10-b6dd9704219e@linaro.org/
>
> On 18/12/2023 07:24, Sumit Garg wrote:
> > Signed-off-by: Sumit Garg <sumit.garg at linaro.org>
> > ---
> >  drivers/serial/serial_msm.c | 7 +++++++
> >  1 file changed, 7 insertions(+)
> >
> > diff --git a/drivers/serial/serial_msm.c b/drivers/serial/serial_msm.c
> > index a22623c316e..43e58595dc2 100644
> > --- a/drivers/serial/serial_msm.c
> > +++ b/drivers/serial/serial_msm.c
> > @@ -16,6 +16,7 @@
> >  #include <serial.h>
> >  #include <watchdog.h>
> >  #include <asm/global_data.h>
> > +#include <asm/gpio.h>
> >  #include <asm/io.h>
> >  #include <linux/compiler.h>
> >  #include <linux/delay.h>
> > @@ -210,6 +211,7 @@ static int msm_serial_probe(struct udevice *dev)
> >  {
> >       int ret;
> >       struct msm_serial_data *priv = dev_get_priv(dev);
> > +     struct gpio_desc rs232_0, rs232_1;
> >
> >       /* No need to reinitialize the UART after relocation */
> >       if (gd->flags & GD_FLG_RELOC)
> > @@ -219,6 +221,11 @@ static int msm_serial_probe(struct udevice *dev)
> >       if (ret)
> >               return ret;
> >
> > +     if (!gpio_request_by_name(dev, "gpios", 0, &rs232_0, GPIOD_IS_OUT))
> > +             dm_gpio_set_value(&rs232_0, 1);
> > +     if (!gpio_request_by_name(dev, "gpios", 1, &rs232_1, GPIOD_IS_OUT))
> > +             dm_gpio_set_value(&rs232_1, 0);
> > +
> >       pinctrl_select_state(dev, "uart");
> >       uart_dm_init(priv);
> >
>
> --
> // Caleb (they/them)