[v9,02/10] serial: sc16is7xx: mark IOCONTROL register as volatile

From: Hugo Villeneuve <hvilleneuve@dimonoff.com>

Bit SRESET (3) is cleared when a reset operation is completed. Having
the IOCONTROL register as non-volatile will always read SRESET as 1,
which is incorrect.

Also, if IOCONTROL register is not a volatile register, the upcoming
patch "serial: sc16is7xx: fix regression with GPIO configuration"
doesn't work when setting some shared GPIO lines as modem control
lines.

Therefore mark IOCONTROL register as a volatile register.

Cc: <stable@vger.kernel.org> # 6.1.x
Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Reviewed-by: Lech Perczak <lech.perczak@camlingroup.com>
Tested-by: Lech Perczak <lech.perczak@camlingroup.com>
---
 drivers/tty/serial/sc16is7xx.c | 1 +
 1 file changed, 1 insertion(+)

On Tue, Jul 25, 2023 at 10:23:34AM -0400, Hugo Villeneuve wrote:
> From: Hugo Villeneuve <hvilleneuve@dimonoff.com>
> 
> Bit SRESET (3) is cleared when a reset operation is completed. Having
> the IOCONTROL register as non-volatile will always read SRESET as 1,
> which is incorrect.
> 
> Also, if IOCONTROL register is not a volatile register, the upcoming
> patch "serial: sc16is7xx: fix regression with GPIO configuration"
> doesn't work when setting some shared GPIO lines as modem control
> lines.
> 
> Therefore mark IOCONTROL register as a volatile register.
> 
> Cc: <stable@vger.kernel.org> # 6.1.x

Why 6.1.y?  What commit does this fix?

> Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
> Reviewed-by: Lech Perczak <lech.perczak@camlingroup.com>
> Tested-by: Lech Perczak <lech.perczak@camlingroup.com>
> ---
>  drivers/tty/serial/sc16is7xx.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c
> index 8ae2afc76a9b..306ae512b38a 100644
> --- a/drivers/tty/serial/sc16is7xx.c
> +++ b/drivers/tty/serial/sc16is7xx.c
> @@ -488,6 +488,7 @@ static bool sc16is7xx_regmap_volatile(struct device *dev, unsigned int reg)
>  	case SC16IS7XX_TXLVL_REG:
>  	case SC16IS7XX_RXLVL_REG:
>  	case SC16IS7XX_IOSTATE_REG:
> +	case SC16IS7XX_IOCONTROL_REG:
>  		return true;
>  	default:
>  		break;

Is this the same as this change:
	https://lore.kernel.org/all/20230724034727.17335-1-hui.wang@canonical.com/

confused,

greg k-h

On Mon, 31 Jul 2023 17:50:40 +0200
Greg KH <gregkh@linuxfoundation.org> wrote:

> On Tue, Jul 25, 2023 at 10:23:34AM -0400, Hugo Villeneuve wrote:
> > From: Hugo Villeneuve <hvilleneuve@dimonoff.com>
> > 
> > Bit SRESET (3) is cleared when a reset operation is completed. Having
> > the IOCONTROL register as non-volatile will always read SRESET as 1,
> > which is incorrect.
> > 
> > Also, if IOCONTROL register is not a volatile register, the upcoming
> > patch "serial: sc16is7xx: fix regression with GPIO configuration"
> > doesn't work when setting some shared GPIO lines as modem control
> > lines.
> > 
> > Therefore mark IOCONTROL register as a volatile register.
> > 
> > Cc: <stable@vger.kernel.org> # 6.1.x
> 
> Why 6.1.y?  What commit does this fix?
> 
> > Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
> > Reviewed-by: Lech Perczak <lech.perczak@camlingroup.com>
> > Tested-by: Lech Perczak <lech.perczak@camlingroup.com>
> > ---
> >  drivers/tty/serial/sc16is7xx.c | 1 +
> >  1 file changed, 1 insertion(+)
> > 
> > diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c
> > index 8ae2afc76a9b..306ae512b38a 100644
> > --- a/drivers/tty/serial/sc16is7xx.c
> > +++ b/drivers/tty/serial/sc16is7xx.c
> > @@ -488,6 +488,7 @@ static bool sc16is7xx_regmap_volatile(struct device *dev, unsigned int reg)
> >  	case SC16IS7XX_TXLVL_REG:
> >  	case SC16IS7XX_RXLVL_REG:
> >  	case SC16IS7XX_IOSTATE_REG:
> > +	case SC16IS7XX_IOCONTROL_REG:
> >  		return true;
> >  	default:
> >  		break;
> 
> Is this the same as this change:
> 	https://lore.kernel.org/all/20230724034727.17335-1-hui.wang@canonical.com/
> 
> confused,

Hi Greg,
yes this is the same.

You simply accepted an exact equivalent of my patch by someone else in
your tree, no confusion there.

I will remove this patch from my series and rebase it on your tree
gregkh_tty/tty-next.

Hugo.