On Tue, 30 May 2023 01:38:17 +0300
andy.shevchenko@xxxxxxxxx wrote:
> Mon, May 29, 2023 at 10:07:09AM -0400, Hugo Villeneuve kirjoitti:
> > From: Hugo Villeneuve <hvilleneuve@xxxxxxxxxxxx>
> >
> > Commit 679875d1d880 ("sc16is7xx: Separate GPIOs from modem control lines")
> > and commit 21144bab4f11 ("sc16is7xx: Handle modem status lines")
> > changed the function of the GPIOs pins to act as modem control
> > lines without any possibility of selecting GPIO function.
> >
> > As a consequence, applications that depends on GPIO lines configured
> > by default as GPIO pins no longer work as expected.
> >
> > Also, the change to select modem control lines function was done only
> > for channel A of dual UART variants (752/762). This was not documented
> > in the log message.
> >
> > Allow to specify GPIO or modem control line function in the device
> > tree, and for each of the ports (A or B).
> >
> > Do so by using the new device-tree property named
> > "modem-control-line-ports" (property added in separate patch).
> >
> > When registering GPIO chip controller, mask-out GPIO pins declared as
> > modem control lines according to this new "modem-control-line-ports"
> > DT property.
> >
> > Boards that need to have GPIOS configured as modem control lines
> > should add that property to their device tree. Here is a list of
> > boards using the sc16is7xx driver in their device tree and that may
> > need to be modified:
> > arm64/boot/dts/freescale/fsl-ls1012a-frdm.dts
> > mips/boot/dts/ingenic/cu1830-neo.dts
> > mips/boot/dts/ingenic/cu1000-neo.dts
>
> ...
>
> > Fixes: 679875d1d880 ("sc16is7xx: Separate GPIOs from modem control lines")
> > Fixes: 21144bab4f11 ("sc16is7xx: Handle modem status lines")
>
> Don't forget to refer to the dependency patches form this series.
> (I forgot how it should be done, IIRC the documentation about stable kernel
> patches can shed a light on this.)
Hi,
I will look into it.
> ...
>
> > + switch (mctrl_mask) {
> > + case 0:
> > + s->gpio_valid_mask = 0xFF;
>
> GENMASK()
>
> > + break;
> > + case SC16IS7XX_IOCONTROL_MODEM_A_BIT:
> > + s->gpio_valid_mask = 0x0F;
>
> GENMASK()
>
> > + break;
> > + case SC16IS7XX_IOCONTROL_MODEM_B_BIT:
> > + s->gpio_valid_mask = 0xF0;
>
> GENMASK()
Ok done, altough even if in general I like the bit manipulation macros because they make the code easier to read/understand, I find it less obvious by using GENMASK in this case IMMO.
> > + break;
> > + default:
> > + break;
> > + }
>
> ...
>
> > + of_property_for_each_u32(dev->of_node, "nxp,modem-control-line-ports",
> > + prop, p, u) {
> > + if (u >= devtype->nr_uart)
> > + continue;
> > +
> > + /* Use GPIO lines as modem control lines */
> > + if (u == 0)
> > + mctrl_mask |= SC16IS7XX_IOCONTROL_MODEM_A_BIT;
> > + else if (u == 1)
> > + mctrl_mask |= SC16IS7XX_IOCONTROL_MODEM_B_BIT;
> > + }
>
> Can we use device properties, please?
I have converted this section to use device_property_count_u32() and device_property_read_u32_array(). Is that Ok?
> If you think about backporting to the earlier kernels (w/o properties in use in
> this driver), perhaps an additional followup for that?
I am not sure what you mean by this?
