Re: [PATCH 2/2] gpio: omap: save two lines by using devm_clk_get_prepared()

[Matti Vaittinen <mazziesaccount@gmail.com>]

Hi deeeee Ho peeps!

On 03/12/2024 18:41, Bartosz Golaszewski wrote:
> From: Bartosz Golaszewski <bartosz.golaszewski@linaro.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@linaro.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.

Yours,
	-- Matti