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Message-ID: <a175fd56-c21b-46f5-bd0a-ccaa7c0f3efa@gmail.com>
Date: Fri, 13 Dec 2024 15:55:43 +0200
From: Matti Vaittinen <mazziesaccount@...il.com>
To: "Sverdlin, Alexander" <alexander.sverdlin@...mens.com>,
"ssantosh@...nel.org" <ssantosh@...nel.org>, "brgl@...ev.pl"
<brgl@...ev.pl>, "khilman@...nel.org" <khilman@...nel.org>,
"linus.walleij@...aro.org" <linus.walleij@...aro.org>,
"grygorii.strashko@...com" <grygorii.strashko@...com>
Cc: "bartosz.golaszewski@...aro.org" <bartosz.golaszewski@...aro.org>,
"linux-gpio@...r.kernel.org" <linux-gpio@...r.kernel.org>,
"tony@...mide.com" <tony@...mide.com>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"geert+renesas@...der.be" <geert+renesas@...der.be>,
"linux-omap@...r.kernel.org" <linux-omap@...r.kernel.org>
Subject: Re: [PATCH 2/2] gpio: omap: save two lines by using
devm_clk_get_prepared()
On 13/12/2024 14:29, Sverdlin, Alexander wrote:
> Hey Matti, how are you?
Hiya Alex!
Fine fine, just feeling a bit (a lot) older :) I hope Siemens(?) has
been treating You well! Good to see you're still actively working with
upstream stuff! It'd be great to see you again, maybe in some conference ;)
And just in case you see other good old Ulmians - say: "Hi dee Ho
peeps!" - from me ;)
> On Fri, 2024-12-13 at 14:16 +0200, Matti Vaittinen wrote:
>>> From: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
>>>
>>> We can drop the else branch if we get the clock already prepared using
>>> the relevant helper.
>>>
>>> Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
>>> ---
>>
>> Booting a beaglebone black with the linux-next from Today fails
>> (next-20241213). Enabling earlycon + debug yields below splat to be
>> printed to the console:
>>
>> [ 2.628019] ------------[ cut here ]------------
>> [ 2.632793] WARNING: CPU: 0 PID: 34 at drivers/clk/clk.c:1254
>> clk_core_enable+0xb4/0x1b0
>> [ 2.641156] Enabling unprepared l4-wkup-clkctrl:0008:18
>> [ 2.646530] Modules linked in:
>> [ 2.649688] CPU: 0 UID: 0 PID: 34 Comm: kworker/u4:3 Not tainted
>> 6.13.0-rc2-next-20241213-00002-gf2d4b29c8330 #15
>> [ 2.660256] Hardware name: Generic AM33XX (Flattened Device Tree)
>> [ 2.666531] Workqueue: events_unbound deferred_probe_work_func
>> [ 2.672553] Call trace:
>> [ 2.672570] unwind_backtrace from show_stack+0x10/0x14
>> [ 2.680578] show_stack from dump_stack_lvl+0x50/0x64
>> [ 7 2.685788] dump_stack_lvl from __warn+0xc0/0x130
>> [ 2.690734] __warn from warn_slowpath_fmt+0x80/0x1a0
>> [ 2.695944] warn_slowpath_fmt from clk_core_enable+0xb4/0x1b0
>> [ 2.701963] clk_core_enable from clk_core_enable_lock+0x18/0x2c
>> [ 2.708159] clk_core_enable_lock from
>> sysc_enable_opt_clocks.part.9+0x28/0x84
>> [ 2.715611] sysc_enable_opt_clocks.part.9 from
>> sysc_enable_module+0x254/0x2dc
>> [ 2.723052] sysc_enable_module from sysc_runtime_resume+0x17c/0x1c0
>> [ 2.729599] sysc_runtime_resume from __rpm_callback+0x4c/0x130
>> [ 2.735709] __rpm_callback from rpm_callback+0x50/0x54
>> [ 2.741096] rpm_callback from rpm_resume+0x614/0x660
>> [ 2.746304] rpm_resume from __pm_runtime_resume+0x4c/0x64
>> [ 2.751960] __pm_runtime_resume from __device_attach+0xd0/0x188
>> [ 2.758155] __device_attach from bus_probe_device+0x88/0x8c
>> or_thread from kthread+0x188/0x24c
>> [ 2.789476] kthread from ret_from_fork+0x14/0x20
>> [ 2.794327] Exception stack(0xe0091fb0 to 0xe0091ff8)
>> [ 2.799528] 1fa0: 00000000
>> 00000000 00000000 00000000
>> [ 2.807947] 1fc0: 00000000 00000000 00000000 00000000 00000000
>> 00000000 00000000 00000000
>> [ 2.816365] 1fe0: 00000000 00000000 00000000 00000000 00000013 00000000
>> [ 2.823173] ---[ end trace 0000000000000000 ]---
>> [ 2.828070] ti-sysc 44e07000.target-module: Optional clocks failed
>> for enable: -108
>> [ 2.835998] ------------[ cut here ]------------
>>
>> reverting
>> b7bbaff8c1bc ("gpio: omap: save two lines by using devm_clk_get_prepared()")
>>
>> fixes the boot for me.
>>
>>
>>> drivers/gpio/gpio-omap.c | 4 +---
>>> 1 file changed, 1 insertion(+), 3 deletions(-)
>>>
>>> diff --git a/drivers/gpio/gpio-omap.c b/drivers/gpio/gpio-omap.c
>>> index 54c4bfdccf568..57d299d5d0b16 100644
>>> --- a/drivers/gpio/gpio-omap.c
>>> +++ b/drivers/gpio/gpio-omap.c
>>> @@ -1449,13 +1449,11 @@ static int omap_gpio_probe(struct platform_device *pdev)
>>> }
>>>
>>> if (bank->dbck_flag) {
>>> - bank->dbck = devm_clk_get(dev, "dbclk");
>>> + bank->dbck = devm_clk_get_prepared(dev, "dbclk");
>>> if (IS_ERR(bank->dbck)) {
>>> dev_err(dev,
>>> "Could not get gpio dbck. Disable debounce\n");
>>> bank->dbck_flag = false;
>>> - } else {
>>> - clk_prepare(bank->dbck);
>>> }
>>> }
>>>
>>
>> I can only spot a minor functional change. The code prior this commit
>> does not check the result of clk_prepare(), and does neither set
>> bank->dbck_flag = false; nor call clk_put();
>>
>> Other than that, timing is likely to be changed. Not sure what is the
>> thing here.
>
> The new code looks more correct, with the return code check from clk_prepare().
I agree. Unfortunately something breaks though.
> Could it be that two problems eliminated themselves in your case before? ;-)
Ha. Would it be the first time? ;) Well, unfortunately I really don't
know the omap/am335x stuff too well. Maybe Tony (CC) or Grygori know
better - I think they have helped me with BBB related stuff before :)
> Would it be possible for you to provide the logs with "initcall_debug" with
> and without the patch in question?
Logs attached :) minicom_reverted.cap has is the next-20241213 having
this commit reverted. minicom_not_reverted.cap is just the next-20241213.
Unfortunately it seems there are some errors (flipped bits?) in the
serial log. Not sure what causes them - I have new FTDI chip, perhaps it
causes these problems. (Comparison of the logs shows single, seemingly
random, letters being changed.)
Yours,
-- Matti
Download attachment "minicom_not_reverted.cap" of type "application/vnd.tcpdump.pcap" (112394 bytes)
Download attachment "minicom_reverted.cap" of type "application/vnd.tcpdump.pcap" (212655 bytes)
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