The devm_clk_get_enabled() helpers:
    - call devm_clk_get()
    - call clk_prepare_enable() and register what is needed in order to
     call clk_disable_unprepare() when needed, as a managed resource.

This simplifies the code and avoids calls to clk_disable_unprepare().

Signed-off-by: Lei Liu <liulei.rjpt@vivo.com>
---
 drivers/tty/serial/mps2-uart.c | 9 +--------
 1 file changed, 1 insertion(+), 8 deletions(-)

diff --git a/drivers/tty/serial/mps2-uart.c b/drivers/tty/serial/mps2-uart.c
index 2a4c09f3a834..e582fd6c4632 100644
--- a/drivers/tty/serial/mps2-uart.c
+++ b/drivers/tty/serial/mps2-uart.c
@@ -550,19 +550,12 @@ static int mps2_init_port(struct platform_device *pdev,
 	mps_port->port.ops = &mps2_uart_pops;
 	mps_port->port.dev = &pdev->dev;
 
-	mps_port->clk = devm_clk_get(&pdev->dev, NULL);
+	mps_port->clk = devm_clk_get_enabled(&pdev->dev, NULL);
 	if (IS_ERR(mps_port->clk))
 		return PTR_ERR(mps_port->clk);
 
-	ret = clk_prepare_enable(mps_port->clk);
-	if (ret)
-		return ret;
-
 	mps_port->port.uartclk = clk_get_rate(mps_port->clk);
 
-	clk_disable_unprepare(mps_port->clk);
-
-
 	if (mps_port->flags & UART_PORT_COMBINED_IRQ) {
 		mps_port->port.irq = platform_get_irq(pdev, 0);
 	} else {
-- 
2.34.1

On Thu, Aug 22, 2024 at 11:39:09AM +0800, Lei Liu wrote:
> The devm_clk_get_enabled() helpers:
>     - call devm_clk_get()
>     - call clk_prepare_enable() and register what is needed in order to
>      call clk_disable_unprepare() when needed, as a managed resource.
> 
> This simplifies the code and avoids calls to clk_disable_unprepare().

...

> -	mps_port->clk = devm_clk_get(&pdev->dev, NULL);
> +	mps_port->clk = devm_clk_get_enabled(&pdev->dev, NULL);
>  	if (IS_ERR(mps_port->clk))
>  		return PTR_ERR(mps_port->clk);
>  
> -	ret = clk_prepare_enable(mps_port->clk);
> -	if (ret)
> -		return ret;
> -
>  	mps_port->port.uartclk = clk_get_rate(mps_port->clk);
>  
> -	clk_disable_unprepare(mps_port->clk);

Your change is not equivalent. In case this clock is shared this may lead to
run-time issues. Hence I don't think this patch is needed in this case.
Instead, you may add a comment on top of devm_clk_get() to explain that we only
need it be enabled to get clock rate in the probe.

-- 
With Best Regards,
Andy Shevchenko

on 2024/8/22 21:19, Andy Shevchenko wrote:
> On Thu, Aug 22, 2024 at 11:39:09AM +0800, Lei Liu wrote:
>> The devm_clk_get_enabled() helpers:
>>      - call devm_clk_get()
>>      - call clk_prepare_enable() and register what is needed in order to
>>       call clk_disable_unprepare() when needed, as a managed resource.
>>
>> This simplifies the code and avoids calls to clk_disable_unprepare().
> ...
>
>> -	mps_port->clk = devm_clk_get(&pdev->dev, NULL);
>> +	mps_port->clk = devm_clk_get_enabled(&pdev->dev, NULL);
>>   	if (IS_ERR(mps_port->clk))
>>   		return PTR_ERR(mps_port->clk);
>>   
>> -	ret = clk_prepare_enable(mps_port->clk);
>> -	if (ret)
>> -		return ret;
>> -
>>   	mps_port->port.uartclk = clk_get_rate(mps_port->clk);
>>   
>> -	clk_disable_unprepare(mps_port->clk);
> Your change is not equivalent. In case this clock is shared this may lead to
> run-time issues. Hence I don't think this patch is needed in this case.
> Instead, you may add a comment on top of devm_clk_get() to explain that we only
> need it be enabled to get clock rate in the probe.

Thank you for your suggestion. I will adopt your advice in the second 
version of the patch and make no changes.

---
With Best Regards,

Lei Liu