From: Stefan Wahren <stefan.wahren@i2se.com>
To: Florian Fainelli <f.fainelli@gmail.com>,
"linus.walleij" <linus.walleij@linaro.org>,
linux-arm-kernel <linux-arm-kernel@lists.infradead.org>
Cc: Phil Elwell <phil@raspberrypi.com>
Subject: Re: DTB backward/forward compatibility with "pinctrl: bcm2835: Change init order for gpio hogs"
Date: Tue, 8 Mar 2022 20:13:44 +0100 [thread overview]
Message-ID: <75266ed1-666a-138b-80f1-ae9a06b7bdf3@i2se.com> (raw)
In-Reply-To: <e335eeba-a527-04c3-3cac-9d80387bb9fc@i2se.com>
Am 07.03.22 um 12:38 schrieb Stefan Wahren:
> Hi,
>
> Am 06.03.22 um 17:54 schrieb Florian Fainelli:
>> Hi Stefan,
>>
>> On 3/6/2022 7:03 AM, Stefan Wahren wrote:
>>> Hi Florian,
>>>
>>> it seems that other platform stumbled on the same issue:
>>>
>>> https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?h=next-20220304&id=9b4924da4711674e62d97d4f5360446cc78337af
>>>
>>>
>>> https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?h=next-20220304&id=7ed07855773814337b9814f1c3e866df52ebce68
>>>
>>>
>>> I will try to prepare a patch.
>> Thank you! Do you think we could have a core function expose which
>> would do essentially avoid drivers having to sprinkle checks for the
>> absence of a 'gpio-ranges' property?
> unfortunately my first attempts to implement it similiar to the
> solutions above failed. I read the explanations from the original fix
> from Christian Lamparter [1] and from my understanding the backward
> compatibility must be implemented into gpiochip_add_data() or a variant.
> Before the gpiochip is not registered and afterwards it would be too late.
>
> My test scenario (worst case) is an additional gpio hog for the
> Raspberry Pi 3 B with removed gpio-ranges:
>
Not sure this is the right place, but the following hack make the
Raspberry Pi boot for the defined worst case szenario (no gpio-ranges
but at least one gpio-hog):
diff --git a/drivers/gpio/gpiolib-of.c b/drivers/gpio/gpiolib-of.c
index 91dcf2c..23386dd 100644
--- a/drivers/gpio/gpiolib-of.c
+++ b/drivers/gpio/gpiolib-of.c
@@ -933,6 +933,24 @@ static int of_gpiochip_add_pin_range(struct
gpio_chip *chip
)
if (!np)
return 0;
+ if (!of_property_read_bool(np, "gpio-ranges")) {
+ pr_warn("%pOF: gpio-ranges missing. Try to fallback!\n",
np);
+
+ pctldev = of_pinctrl_get(np);
+ of_node_put(np);
+
+ if (!pctldev)
+ return 0;
+
+ gpiochip_add_pin_range(chip,
+ pinctrl_dev_get_devname(pctldev),
+ 0,
+ 0,
+ chip->ngpio);
+
+ return 0;
+ }
+
group_names = of_find_property(np, group_names_propname, NULL);
for (;; index++) {
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next prev parent reply other threads:[~2022-03-08 19:24 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-25 19:39 DTB backward/forward compatibility with "pinctrl: bcm2835: Change init order for gpio hogs" Florian Fainelli
2022-01-25 19:48 ` Phil Elwell
2022-01-25 19:58 ` Florian Fainelli
2022-01-26 1:33 ` Florian Fainelli
2022-01-27 16:31 ` Stefan Wahren
2022-03-06 15:03 ` Stefan Wahren
2022-03-06 16:54 ` Florian Fainelli
2022-03-06 17:58 ` Stefan Wahren
2022-03-07 11:38 ` Stefan Wahren
2022-03-08 19:13 ` Stefan Wahren [this message]
2022-03-09 1:10 ` Florian Fainelli
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