From: Sakari Ailus <sakari.ailus@iki.fi>
To: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: "Mani, Rajmohan" <rajmohan.mani@intel.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-gpio@vger.kernel.org" <linux-gpio@vger.kernel.org>,
"linux-acpi@vger.kernel.org" <linux-acpi@vger.kernel.org>,
Lee Jones <lee.jones@linaro.org>,
Linus Walleij <linus.walleij@linaro.org>,
Alexandre Courbot <gnurou@gmail.com>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
Len Brown <lenb@kernel.org>
Subject: Re: [PATCH v1 2/3] gpio: Add support for TPS68470 GPIOs
Date: Sun, 11 Jun 2017 19:50:28 +0300 [thread overview]
Message-ID: <20170611165028.GA12407@valkosipuli.retiisi.org.uk> (raw)
In-Reply-To: <CAHp75VeJaQjWb1834Nt7178GL72rcym=d3zV8tPpvJ5qKDuM_Q@mail.gmail.com>
Hi Andy,
On Sun, Jun 11, 2017 at 04:40:16PM +0300, Andy Shevchenko wrote:
> On Sun, Jun 11, 2017 at 2:30 PM, Sakari Ailus <sakari.ailus@iki.fi> wrote:
> > On Sun, Jun 11, 2017 at 03:49:18AM +0000, Mani, Rajmohan wrote:
> >> > On Tue, Jun 6, 2017 at 2:55 PM, Rajmohan Mani <rajmohan.mani@intel.com>
> >> > wrote:
>
> >> > Besides my below comments, just put it here that I recommended earlier to
> >> > provide 2 GPIO chips (one per bank of GPIOs).
> >> > It's up to Linus to decide since you didn't follow the recommendation.
>
> >> Did you mean to add this in Kconfig or this source file?
> >>
> >> Here's some more details on these GPIOs.
> >> Each of these 7 GPIOs has 2 registers to control the mode, level, drive strength, polarity, hysteresis control among other things. Also there are GPDI and GPDO registers to control the input and output values of these 7 GPIOs. These GPIOs are numbered 0 through 6.
> >> The remaining 3 GPIOs are more of special purpose GPIOs that are output only, with one register to control all of their output values and drive strengths. These GPIOs are named with a special purpose (ENABLE, IDLE and RESET of the sensor).
>
> >> > > +#include <linux/mfd/tps68470.h>
> >> > > +#include <linux/module.h>
> >> > > +#include <linux/platform_device.h>
> >> >
> >> > > + if (offset >= TPS68470_N_REGULAR_GPIO) {
> >> > > + offset -= TPS68470_N_REGULAR_GPIO;
> >> > > + reg = TPS68470_REG_SGPO;
> >> > > + }
> >> >
> >> > Two GPIO chips makes this gone.
> >
> > Again, I'm not really worried about this driver, but the ACPI tables. How
> > does the difference show there?
>
> Same way. You will have common numbering over the chip [0, 9]. It will
> be just an abstraction inside the driver.
Oh, in that case that should be a non-issue.
>
> > The outputs (s_enable, s_idle and s_resetn) are not numbered in the
> > documentation. There grouped, though, but the order in that grouping varies.
>
> I don't get this. You are telling that the property of "always output"
> can be assigned to any 3 out of 10?
No, I'm telling you that the three (s_enable, s_idle and s_resetn) cannot be
configured as inputs --- instead they're always outputs. That's how the
hardware is implemented.
> Above states the opposite, so, it's clear to me that abstraction of 2
> GPIO chips over 1 can be utilized here.
Sounds fine to me, taken that this does not add complications to ACPI
tables.
--
Regards,
Sakari Ailus
e-mail: sakari.ailus@iki.fi XMPP: sailus@retiisi.org.uk
next prev parent reply other threads:[~2017-06-11 16:50 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-06-06 11:55 [PATCH v1 0/3] TPS68470 PMIC drivers Rajmohan Mani
2017-06-06 11:55 ` [PATCH v1 1/3] mfd: Add new mfd device TPS68470 Rajmohan Mani
2017-06-06 12:48 ` Heikki Krogerus
2017-06-09 22:04 ` Mani, Rajmohan
2017-06-06 12:59 ` Andy Shevchenko
2017-06-07 11:58 ` Sakari Ailus
2017-06-09 22:12 ` Mani, Rajmohan
2017-06-12 8:20 ` Lee Jones
2017-06-12 9:20 ` Mani, Rajmohan
2017-07-19 23:23 ` Mani, Rajmohan
2017-07-20 8:15 ` Lee Jones
2017-06-09 22:09 ` Mani, Rajmohan
2017-06-07 2:10 ` kbuild test robot
2017-06-07 10:07 ` kbuild test robot
2017-06-06 11:55 ` [PATCH v1 2/3] gpio: Add support for TPS68470 GPIOs Rajmohan Mani
2017-06-06 14:15 ` Andy Shevchenko
2017-06-11 3:49 ` Mani, Rajmohan
2017-06-11 11:30 ` Sakari Ailus
2017-06-11 13:40 ` Andy Shevchenko
2017-06-11 16:50 ` Sakari Ailus [this message]
2017-06-11 19:43 ` Andy Shevchenko
2017-06-12 9:17 ` Mani, Rajmohan
2017-06-12 9:29 ` Andy Shevchenko
2017-06-12 9:51 ` Mani, Rajmohan
2017-06-09 11:15 ` Linus Walleij
2017-06-11 5:04 ` Mani, Rajmohan
2017-06-12 0:18 ` Mani, Rajmohan
2017-06-06 11:55 ` [PATCH v1 3/3] ACPI / PMIC: Add TI PMIC TPS68470 operation region driver Rajmohan Mani
2017-06-06 14:23 ` Andy Shevchenko
2017-06-06 15:21 ` Hans de Goede
2017-06-09 22:20 ` Mani, Rajmohan
2017-06-07 12:15 ` Sakari Ailus
2017-06-07 13:40 ` Andy Shevchenko
2017-06-07 20:10 ` Sakari Ailus
2017-06-07 20:40 ` Andy Shevchenko
2017-06-07 21:12 ` Sakari Ailus
2017-06-09 23:38 ` Mani, Rajmohan
2017-06-10 0:10 ` Mani, Rajmohan
2017-06-08 7:03 ` Hans de Goede
2017-06-09 23:47 ` Mani, Rajmohan
2017-06-09 22:19 ` Mani, Rajmohan
2017-06-07 12:07 ` Sakari Ailus
2017-06-07 13:37 ` Andy Shevchenko
2017-06-07 20:06 ` Sakari Ailus
2017-06-10 0:07 ` Mani, Rajmohan
2017-06-10 0:09 ` Mani, Rajmohan
2017-06-10 0:04 ` Mani, Rajmohan
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