From: Michael Walle <michael@walle.cc>
To: Drew Fustini <drew@beagleboard.org>
Cc: Linus Walleij <linus.walleij@linaro.org>,
Rob Herring <robh+dt@kernel.org>,
Bartosz Golaszewski <bgolaszewski@baylibre.com>,
Paul Walmsley <paul.walmsley@sifive.com>,
Palmer Dabbelt <palmer@dabbelt.com>,
Michael Zhu <michael.zhu@starfivetech.com>,
Geert Uytterhoeven <geert@linux-m68k.org>,
Fu Wei <tekkamanninja@gmail.com>,
linux-kernel <linux-kernel@vger.kernel.org>,
"open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>,
linux-riscv <linux-riscv@lists.infradead.org>,
"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS"
<devicetree@vger.kernel.org>,
Emil Renner Berthing <kernel@esmil.dk>,
Huan Feng <huan.feng@starfivetech.com>
Subject: Re: [RFC PATH 2/2] gpio: starfive-jh7100: Add StarFive JH7100 GPIO driver
Date: Mon, 26 Jul 2021 09:21:31 +0200 [thread overview]
Message-ID: <dad13b899b69436acc1804b7c3438639@walle.cc> (raw)
In-Reply-To: <20210726071124.GA9184@x1>
Hi Drew, Hi Linus,
Am 2021-07-26 09:11, schrieb Drew Fustini:
> On Fri, Jul 23, 2021 at 11:04:41PM +0200, Linus Walleij wrote:
>> On Thu, Jul 1, 2021 at 8:39 AM Michael Walle <michael@walle.cc> wrote:
>> > Am 2021-07-01 02:20, schrieb Drew Fustini:
>> > > Add GPIO driver for the StarFive JH7100 SoC [1] used on the
>> > > BeagleV Starlight JH7100 board [2].
>> > >
>> > > [1] https://github.com/starfive-tech/beaglev_doc/
>> > > [2] https://github.com/beagleboard/beaglev-starlight
>> > >
>> > > Signed-off-by: Emil Renner Berthing <kernel@esmil.dk>
>> > > Signed-off-by: Huan Feng <huan.feng@starfivetech.com>
>> > > Signed-off-by: Drew Fustini <drew@beagleboard.org>
>> >
>> > Could this driver use GPIO_REGMAP and REGMAP_IRQ? See
>> > drivers/gpio/gpio-sl28cpld.c for an example.
>>
>> To me it looks just memory-mapped?
>>
>> Good old gpio-mmio.c (select GPIO_GENERIC) should
>> suffice I think.
But that doesn't mean gpio-regmap can't be used, no? Or what are
the advantages of gpio-mmio?
>> Drew please look at drivers/gpio/gpio-ftgpio010.c for an example
>> of GPIO_GENERIC calling bgpio_init() in probe().
>
> Thank you for the suggestion. However, I am not sure that will work for
> this SoC.
>
> The GPIO registers are described in section 12 of JH7100 datasheet [1]
> and I don't think they fit the expectation of gpio-mmio.c because there
> is a seperate register for each GPIO line for output data value and
> output enable.
>
> There are 64 output data config registers which are 4 bytes wide. There
> are 64 output enable config registers which are 4 bytes wide too.
> Output
> data and output enable registers for a given GPIO pad are contiguous.
> GPIO0_DOUT_CFG is 0x50 and GPIO0_DOEN_CFG is 0x54 while GPIO1_DOUT_CFG
> is 0x58 and GPIO1_DOEN_CFG is 0x5C. The stride between GPIO pads is
> effectively 8, which yields the formula: GPIOn_DOUT_CFG is 0x50+8n.
> Similarly, GPIO0_DOEN_CFG is 0x54 and thus GPIOn_DOEN_CFG is 0x54+8n.
>
> However, GPIO input data does use just one bit for each line. GPIODIN_0
> at 0x48 covers GPIO[31:0] and GPIODIN_1 at 0x4c covers GPIO[63:32].
I'd say, that should work with the .reg_mask_xlate of the gpio-regmap.
-michael
> Thus the input could work with gpio-mmio but I am not sure how to
> reconcile the register-per-gpio for the output value and output enable.
>
> Is there way a way to adapt gpio-mmio for this situation?
>
> Thanks,
> Drew
>
> [1] https://github.com/starfive-tech/beaglev_doc
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next prev parent reply other threads:[~2021-07-26 7:22 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-01 0:20 [RFC PATH 0/2] gpio: starfive-jh7100: Add StarFive JH7100 GPIO bindings and driver Drew Fustini
2021-07-01 0:20 ` [RFC PATH 1/2] dt-bindings: gpio: add starfive,jh7100-gpio bindings Drew Fustini
2021-07-01 8:34 ` [RFC PATH 1/2] dt-bindings: gpio: add starfive, jh7100-gpio bindings Geert Uytterhoeven
2021-07-02 20:56 ` [RFC PATH 1/2] dt-bindings: gpio: add starfive,jh7100-gpio bindings Drew Fustini
2021-07-02 21:03 ` [RFC PATH 1/2] dt-bindings: gpio: add starfive, jh7100-gpio bindings Geert Uytterhoeven
2021-07-03 6:46 ` [RFC PATH 1/2] dt-bindings: gpio: add starfive,jh7100-gpio bindings Drew Fustini
2021-07-03 8:49 ` [RFC PATH 1/2] dt-bindings: gpio: add starfive, jh7100-gpio bindings Geert Uytterhoeven
2021-07-01 0:20 ` [RFC PATH 2/2] gpio: starfive-jh7100: Add StarFive JH7100 GPIO driver Drew Fustini
2021-07-01 2:25 ` Bin Meng
2021-07-01 20:44 ` Drew Fustini
2021-07-01 6:39 ` Michael Walle
2021-07-01 20:33 ` Drew Fustini
2021-07-02 14:59 ` Michael Walle
2021-07-02 21:00 ` Drew Fustini
2021-07-23 21:04 ` Linus Walleij
2021-07-26 7:11 ` Drew Fustini
2021-07-26 7:21 ` Michael Walle [this message]
2021-07-27 5:28 ` Drew Fustini
2021-07-28 9:49 ` Michael Walle
2021-07-28 10:59 ` Emil Renner Berthing
2021-07-28 11:19 ` Michael Walle
2021-07-28 11:21 ` Emil Renner Berthing
2021-07-02 16:03 ` Andy Shevchenko
2021-07-02 21:06 ` Drew Fustini
2021-07-05 13:29 ` Michael Walle
2021-07-05 14:33 ` Matti Vaittinen
2021-07-15 1:49 ` Ley Foon Tan
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