Date:   Mon, 26 Jun 2017 10:45:22 +0200
From:   Geert Uytterhoeven <geert@...ux-m68k.org>
To:     Linus Walleij <linus.walleij@...aro.org>
Cc:     Jacopo Mondi <jacopo+renesas@...ndi.org>,
        Laurent Pinchart <laurent.pinchart@...asonboard.com>,
        Chris Brandt <chris.brandt@...esas.com>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Russell King <linux@...linux.org.uk>,
        Dong Aisheng <aisheng.dong@....com>,
        Linux-Renesas <linux-renesas-soc@...r.kernel.org>,
        "linux-gpio@...r.kernel.org" <linux-gpio@...r.kernel.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v6 00/8] Renesas RZ/A1 pin and gpio controller

Hi Linus,

On Thu, Jun 22, 2017 at 4:54 PM, Jacopo Mondi <jacopo+renesas@...ndi.org> wrote:
>    this is 6th round of RZ/A1 pin controller patch series.
>
> Where did we stop: discussion from pin controller driver shifted toward two
> new generic pin configuration properties I added to the previous series
> (bi-directional and output-enable).
>
> After a really long discussion, we decided to go for handling internally all
> bi-directional use cases, making the generic property not a requirement for the
> series. Interestingly, we recently found out the number of pins actually
> requiring this flag is less (~half) than what reported by the processor manual,
> so we could have handled these internally from day one :(
>
> We also now manage internally pins requiring IO direction specified in software
> even when configured in alternate function mode (SWIO mode). Most of them are
> handled by the driver, some of them have to come from DTS as the user can freely
> select if they have to be inputs or outputs. For those pins, and after another
> discussion involving NXP developers, we decided to use input-enable and
> output-enable properties. I have just sent a patch to add output-enable to the
> generic pin configuration properties, but it is currently under discussion.
>
> However, none of the pins currently configured by mainline DTS require those
> properties to be specified, so I have dropped in this driver any dependency on
> output-enable property, and I'm using instead the already in place
> PIN_CONFIG_OUTPUT one. Once output-enable will eventually be accepted, we can
> update the driver to make use of it, but since there are no use cases for that
> at the moment, it makes not too much sense holding this series back for that.
>
> The total memory occupation we were so worried about of bi-directional and swio
> pin tables is now around 100 bytes, because of how the number of pins actually
> needing those flags has  reduced and because of how we have arranged the
> tables using bitfield structures (credits to Geert here).
>
> Having cleared out dependencies on new pin configuration properties and having
> made configuration flags a driver specific issue, I hope this version can be
> accepted and land in forthcoming pull request for Renesas PFC updates from
> Geert, pending some feedback from the linux-gpio community.

If this is OK for you, I'd like to include the first 3 patches (plus a small
fix I received offline from Chris Brandt[*]) in my final pull request of
sh-pfc for v4.13 (which I have been postponing in anticipation of this driver).

After v4.13-rc1, Simon can queue up the DTS patches in his tree for v4.14.

Thanks!

[*]

--- a/drivers/pinctrl/pinctrl-rza1.c
+++ b/drivers/pinctrl/pinctrl-rza1.c
@@ -617,11 +617,13 @@ static int rza1_pin_mux_single(struct
rza1_pinctrl *rza1_pctl,
         * to I/O direction specified by pin configuration -after- PMC has been
         * set to one.
         */
-       if (!(mux_flags & (MUX_FLAGS_SWIO_INPUT | MUX_FLAGS_SWIO_OUTPUT)))
+       if (mux_flags & (MUX_FLAGS_SWIO_INPUT | MUX_FLAGS_SWIO_OUTPUT))
+               rza1_set_bit(port, RZA1_PM_REG, pin,
+                            mux_flags & MUX_FLAGS_SWIO_INPUT);
+       else
                rza1_set_bit(port, RZA1_PIPC_REG, pin, 1);

        rza1_set_bit(port, RZA1_PMC_REG, pin, 1);
-       rza1_set_bit(port, RZA1_PM_REG, pin, mux_flags & MUX_FLAGS_SWIO_INPUT);

        return 0;
 }

> v1 -> v2:
> - change pin configuration flags as suggested by Chris
> - gpio set direction function fixed as suggested by Chris
> - add some more example on pin configuration flag usage to dt-binding doc
> - fix gpio-controller names to remove unit address as suggested by Geert
> - some comments chopped here and there to make the driver less verbose
>
> v2 -> v3:
> - fix grammar and syntax in comment and documentation
> - fix code style (reverse xmas tree ordering in variable declaration)
> - use irqsave/irqrestore in spinlock lock/unlock
> - use devm_ version of kasprintf (memory returned was not properly free)
> - use bitops.h operation ffs and fls to make sure a single bit is set in pmx
>   mask
> - Add Geert's reviewed-by to DTS patches
>
> v3 -> v4:
> - use "pinmux" property in pmx sub-nodes in place of "renesas,pins"
> - use pinconf standard properties to set pin mux additional flags
> - add "bi-directional" and "output-enable" to pinconf generic properties
> - perform pmx function parsing at dt_node_to_map() time
> - change DT bindings to use GENERIC_PINCONF
> - change DT bindings to allow sub-nodes to have "pinmux" property specified
> - several renames (register names, DT parse functions, set_mux() function)
>
> v4 -> v5:
> - use pinctrl_enable() function in pin controller registration function
> - update bindings documentation to incorporate Geert's comments
> - add generic properties unpack macros
>
> v5 -> v6:
> - add tables in driver to manage bi-directional and swio flags
> - drop dependecies on new generic pin configuration properties
>
> Jacopo Mondi (8):
>   pinctrl: Renesas RZ/A1 pin and gpio controller
>   dt-bindings: pinctrl: Add RZ/A1 bindings doc
>   arm: dts: dt-bindings: Add Renesas RZ/A1 pinctrl header
>   arm: dts: r7s72100: Add pin controller node
>   arm: dts: genmai: Add SCIF2 pin group
>   arm: dts: genmai: Add RIIC2 pin group
>   arm: dts: genmai: Add user led device nodes
>   arm: dts: genmai: Add ethernet pin group
>
>  .../bindings/pinctrl/renesas,rza1-pinctrl.txt      |  218 ++++
>  arch/arm/boot/dts/r7s72100-genmai.dts              |   69 ++
>  arch/arm/boot/dts/r7s72100.dtsi                    |   78 ++
>  drivers/pinctrl/Kconfig                            |   11 +
>  drivers/pinctrl/Makefile                           |    1 +
>  drivers/pinctrl/pinctrl-rza1.c                     | 1309 ++++++++++++++++++++
>  include/dt-bindings/pinctrl/r7s72100-pinctrl.h     |   16 +
>  7 files changed, 1702 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/pinctrl/renesas,rza1-pinctrl.txt
>  create mode 100644 drivers/pinctrl/pinctrl-rza1.c
>  create mode 100644 include/dt-bindings/pinctrl/r7s72100-pinctrl.h

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

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