From: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
To: Michael Walle <michael@walle.cc>
Cc: linux-kernel@vger.kernel.org, linux-gpio@vger.kernel.org,
Linus Walleij <linus.walleij@linaro.org>,
Bartosz Golaszewski <bgolaszewski@baylibre.com>,
Mark Brown <broonie@kernel.org>,
Andy Shevchenko <andy.shevchenko@gmail.com>
Subject: Re: [PATCH v6 2/3] gpio: add a reusable generic gpio_chip using regmap
Date: Thu, 28 May 2020 13:15:45 -0500 [thread overview]
Message-ID: <6cec4ed5-3a4a-62d8-5209-da3b0863dcd1@linux.intel.com> (raw)
In-Reply-To: <7d281a1e30ea40837ab1a156c561ca6b@walle.cc>
>>> + /* if we have a direction register we need both input and
>>> output */
>>> + if ((config->reg_dir_out_base || config->reg_dir_in_base) &&
>>> + (!config->reg_dat_base || !config->reg_set_base))
>>> + return ERR_PTR(-EINVAL);
>> This failed for me since I didn't have the 'dat' base assigned. I
>> still can't figure out what 'dat' stands for...I just assigned it to
>> the same offset as the 'set' base but really don't understand what
>> this is supposed to do.
>
> DAT is the data register, aka input register, if the GPIO is in input
> mode.
>
> If I read the datasheet correctly you should use the following:
>
> PCM512x_GPIO_EN should be reg_dir_out_base
> PCM512x_GPIO_CONTROL_1 should be reg_set_base
> PCM512x_GPIN should be reg_dat_base
>
> no custom xlate necessary. GPIN looks a bit fishy in that datasheet:
> http://www.ti.com/lit/ds/symlink/pcm5121.pdf?ts=1590684141147
ok, I updated that part - can't test it though with the boards I have,
only output is supported.
> PCM512x_GPIO_OUTPUT_1..6 is pinmux control and shouldn't be part of
> the gpio-regmap. Your driver needs to take care of that.
yes, that's what I did.
>>> +
>>> + /* we don't support having both registers simultaneously for
>>> now */
>>> + if (config->reg_dir_out_base && config->reg_dir_in_base)
>>> + return ERR_PTR(-EINVAL);
>>
>> and this second test seems to contradict the notion of 'both input and
>> output' above?
>
> dir_out_base is used if the register is high active to select an output.
> dir_in_base is used for a low active register. Thus both bases are used
> to switch a GPIO between input and output.
ok, makes sense now, thanks for the explanations.
>> re-adding comment from previous series:
>> >> I still have a series of odd warnings I didn't have before: >> >>
>> [ 101.400263] WARNING: CPU: 3 PID: 1129 at >>
>> drivers/gpio/gpiolib.c:4084 gpiod_set_value+0x3f/0x50 >> >> This seems
>> to come from >> /* Should be using gpiod_set_value_cansleep() */
>>>> WARN_ON(desc->gdev->chip->can_sleep); > > Right now,
>> gpio-regmap hardcodes can_sleep to true. But the only regmap > which
>> don't sleep is regmap-mmio. The PCM512x seems to be either I2C or >
>> SPI, which can both sleep. So this warning is actually correct and >
>> wherever this gpio is set should do it by calling the _cansleep() >
>> version.
>>
>> I still have the warnings with this version, not sure if you wanted to
>> fix it in the v6 or is this needs to be fixed in another piece of
>> code/patch. How would we go about removing this warning?
>
> There is no fix in gpio-regmap. wherever this GPIO is connected to must
> not call gpiod_set_value() but have to use gpiod_set_value_cansleep().
yes, I figured this out and corrected the drivers, works just fine now.
My cleaned-up code is at
https://github.com/thesofproject/linux/pull/1945, I'll resubmit the v2
based on these patches when they are merged and available in Mark
Brown's tree (and I need to address the clock-related feedback).
Thanks for your work Michael, really nice and useful, feel free to add
the following tag:
Tested-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
next prev parent reply other threads:[~2020-05-28 18:46 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-28 14:58 [PATCH v6 0/3] gpio: generic regmap implementation Michael Walle
2020-05-28 14:58 ` [PATCH v6 1/3] gpiolib: Introduce gpiochip_irqchip_add_domain() Michael Walle
2020-05-28 14:58 ` [PATCH v6 2/3] gpio: add a reusable generic gpio_chip using regmap Michael Walle
[not found] ` <adb4eba6-c6c4-a403-dead-1951050eec26@linux.intel.com>
2020-05-28 17:03 ` Michael Walle
2020-05-28 18:15 ` Pierre-Louis Bossart [this message]
2020-05-28 14:58 ` [PATCH v6 3/3] MAINTAINERS: Add gpio regmap section Michael Walle
2020-05-28 15:11 ` [PATCH v6 0/3] gpio: generic regmap implementation Andy Shevchenko
2020-06-03 8:50 ` Linus Walleij
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=6cec4ed5-3a4a-62d8-5209-da3b0863dcd1@linux.intel.com \
--to=pierre-louis.bossart@linux.intel.com \
--cc=andy.shevchenko@gmail.com \
--cc=bgolaszewski@baylibre.com \
--cc=broonie@kernel.org \
--cc=linus.walleij@linaro.org \
--cc=linux-gpio@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=michael@walle.cc \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).