[PATCH 0/8] tty serial drivers use devm_clk_get_enabled() helpers

[PATCH 0/8] tty serial drivers use devm_clk_get_enabled() helpers

[Lei Liu]

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().

Lei Liu (8):
  tty: 8250_ingenic: Use devm_clk_get_enabled() helpers
  tty: 8250_tegra: Use devm_clk_get_enabled() helpers
  tty: 8250_uniphier: Use devm_clk_get_enabled() helpers
  tty: atmel_serial: Use devm_clk_get_enabled() helpers
  tty: mps2-uart: Use devm_clk_get_enabled() helpers
  tty: owl-uart: Use devm_clk_get_enabled() helpers
  tty: st-asc: Use devm_clk_get_enabled() helpers
  tty: stm32-usart: Use devm_clk_get_enabled() helpers

 drivers/tty/serial/8250/8250_ingenic.c  | 26 +++----------------------
 drivers/tty/serial/8250/8250_tegra.c    |  8 +-------
 drivers/tty/serial/8250/8250_uniphier.c |  8 +-------
 drivers/tty/serial/atmel_serial.c       |  8 +-------
 drivers/tty/serial/mps2-uart.c          |  9 +--------
 drivers/tty/serial/owl-uart.c           | 10 +---------
 drivers/tty/serial/st-asc.c             |  8 ++------
 drivers/tty/serial/stm32-usart.c        | 16 +--------------
 8 files changed, 11 insertions(+), 82 deletions(-)

-- 
2.34.1

[PATCH 1/8] tty: 8250_ingenic: Use devm_clk_get_enabled() helpers

[Lei Liu]

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/8250/8250_ingenic.c | 26 +++-----------------------
 1 file changed, 3 insertions(+), 23 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_ingenic.c b/drivers/tty/serial/8250/8250_ingenic.c
index a2783e38a2e3..5f8787309064 100644
--- a/drivers/tty/serial/8250/8250_ingenic.c
+++ b/drivers/tty/serial/8250/8250_ingenic.c
@@ -274,44 +274,26 @@ static int ingenic_uart_probe(struct platform_device *pdev)
 	if (!uart.port.membase)
 		return -ENOMEM;
 
-	data->clk_module = devm_clk_get(&pdev->dev, "module");
+	data->clk_module = devm_clk_get_enabled(&pdev->dev, "module");
 	if (IS_ERR(data->clk_module))
 		return dev_err_probe(&pdev->dev, PTR_ERR(data->clk_module),
 				     "unable to get module clock\n");
 
-	data->clk_baud = devm_clk_get(&pdev->dev, "baud");
+	data->clk_baud = devm_clk_get_enabled(&pdev->dev, "baud");
 	if (IS_ERR(data->clk_baud))
 		return dev_err_probe(&pdev->dev, PTR_ERR(data->clk_baud),
 				     "unable to get baud clock\n");
 
-	err = clk_prepare_enable(data->clk_module);
-	if (err) {
-		dev_err(&pdev->dev, "could not enable module clock: %d\n", err);
-		goto out;
-	}
-
-	err = clk_prepare_enable(data->clk_baud);
-	if (err) {
-		dev_err(&pdev->dev, "could not enable baud clock: %d\n", err);
-		goto out_disable_moduleclk;
-	}
 	uart.port.uartclk = clk_get_rate(data->clk_baud);
 
 	data->line = serial8250_register_8250_port(&uart);
 	if (data->line < 0) {
 		err = data->line;
-		goto out_disable_baudclk;
+		return err;
 	}
 
 	platform_set_drvdata(pdev, data);
 	return 0;
-
-out_disable_baudclk:
-	clk_disable_unprepare(data->clk_baud);
-out_disable_moduleclk:
-	clk_disable_unprepare(data->clk_module);
-out:
-	return err;
 }
 
 static void ingenic_uart_remove(struct platform_device *pdev)
@@ -319,8 +301,6 @@ static void ingenic_uart_remove(struct platform_device *pdev)
 	struct ingenic_uart_data *data = platform_get_drvdata(pdev);
 
 	serial8250_unregister_port(data->line);
-	clk_disable_unprepare(data->clk_module);
-	clk_disable_unprepare(data->clk_baud);
 }
 
 static const struct ingenic_uart_config jz4740_uart_config = {
-- 
2.34.1

Re: [PATCH 1/8] tty: 8250_ingenic: Use devm_clk_get_enabled() helpers

[Paul Cercueil]

Hi Lei Liu,

Le jeudi 22 août 2024 à 11:39 +0800, Lei Liu a écrit :
> 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/8250/8250_ingenic.c | 26 +++---------------------
> --
>  1 file changed, 3 insertions(+), 23 deletions(-)
> 
> diff --git a/drivers/tty/serial/8250/8250_ingenic.c
> b/drivers/tty/serial/8250/8250_ingenic.c
> index a2783e38a2e3..5f8787309064 100644
> --- a/drivers/tty/serial/8250/8250_ingenic.c
> +++ b/drivers/tty/serial/8250/8250_ingenic.c
> @@ -274,44 +274,26 @@ static int ingenic_uart_probe(struct
> platform_device *pdev)
>  	if (!uart.port.membase)
>  		return -ENOMEM;
>  
> -	data->clk_module = devm_clk_get(&pdev->dev, "module");
> +	data->clk_module = devm_clk_get_enabled(&pdev->dev,
> "module");
>  	if (IS_ERR(data->clk_module))
>  		return dev_err_probe(&pdev->dev, PTR_ERR(data-
> >clk_module),
>  				     "unable to get module
> clock\n");
>  
> -	data->clk_baud = devm_clk_get(&pdev->dev, "baud");
> +	data->clk_baud = devm_clk_get_enabled(&pdev->dev, "baud");
>  	if (IS_ERR(data->clk_baud))
>  		return dev_err_probe(&pdev->dev, PTR_ERR(data-
> >clk_baud),
>  				     "unable to get baud clock\n");
>  
> -	err = clk_prepare_enable(data->clk_module);
> -	if (err) {
> -		dev_err(&pdev->dev, "could not enable module clock:
> %d\n", err);
> -		goto out;
> -	}
> -
> -	err = clk_prepare_enable(data->clk_baud);
> -	if (err) {
> -		dev_err(&pdev->dev, "could not enable baud clock:
> %d\n", err);
> -		goto out_disable_moduleclk;
> -	}
>  	uart.port.uartclk = clk_get_rate(data->clk_baud);
>  
>  	data->line = serial8250_register_8250_port(&uart);
>  	if (data->line < 0) {
>  		err = data->line;
> -		goto out_disable_baudclk;
> +		return err;

Not really worth a V2, but if you make a V2, please "return data-
>line;" directly.

Acked-by: Paul Cercueil <paul@crapouillou.net>

Cheers,
-Paul

>  	}
>  
>  	platform_set_drvdata(pdev, data);
>  	return 0;
> -
> -out_disable_baudclk:
> -	clk_disable_unprepare(data->clk_baud);
> -out_disable_moduleclk:
> -	clk_disable_unprepare(data->clk_module);
> -out:
> -	return err;
>  }
>  
>  static void ingenic_uart_remove(struct platform_device *pdev)
> @@ -319,8 +301,6 @@ static void ingenic_uart_remove(struct
> platform_device *pdev)
>  	struct ingenic_uart_data *data = platform_get_drvdata(pdev);
>  
>  	serial8250_unregister_port(data->line);
> -	clk_disable_unprepare(data->clk_module);
> -	clk_disable_unprepare(data->clk_baud);
>  }
>  
>  static const struct ingenic_uart_config jz4740_uart_config = {

Re: [PATCH 1/8] tty: 8250_ingenic: Use devm_clk_get_enabled() helpers

[Andy Shevchenko]

On Thu, Aug 22, 2024 at 11:40:46AM +0200, Paul Cercueil wrote:
> Le jeudi 22 août 2024 à 11:39 +0800, Lei Liu a écrit :

...

> Not really worth a V2, but if you make a V2, please "return data-
> >line;" directly.

> Acked-by: Paul Cercueil <paul@crapouillou.net>

Despite of this, the series has other small issues that needs to be addressed,
so I would wait for v2.

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH 1/8] tty: 8250_ingenic: Use devm_clk_get_enabled() helpers

[Andy Shevchenko]

On Thu, Aug 22, 2024 at 11:39:05AM +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().

...

>  	data->line = serial8250_register_8250_port(&uart);
>  	if (data->line < 0) {
>  		err = data->line;
> -		goto out_disable_baudclk;
> +		return err;
>  	}

	data->line = serial8250_register_8250_port(&uart);
	if (data->line < 0)
		return data->line;

-- 
With Best Regards,
Andy Shevchenko

[PATCH 2/8] tty: 8250_tegra: Use devm_clk_get_enabled() helpers

[Lei Liu]

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/8250/8250_tegra.c | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_tegra.c b/drivers/tty/serial/8250/8250_tegra.c
index 60a80d00d251..a38a4eb3235b 100644
--- a/drivers/tty/serial/8250/8250_tegra.c
+++ b/drivers/tty/serial/8250/8250_tegra.c
@@ -86,16 +86,12 @@ static int tegra_uart_probe(struct platform_device *pdev)
 		return PTR_ERR(uart->rst);
 
 	if (!port->uartclk) {
-		uart->clk = devm_clk_get(&pdev->dev, NULL);
+		uart->clk = devm_clk_get_enabled(&pdev->dev, NULL);
 		if (IS_ERR(uart->clk)) {
 			dev_err(&pdev->dev, "failed to get clock!\n");
 			return -ENODEV;
 		}
 
-		ret = clk_prepare_enable(uart->clk);
-		if (ret < 0)
-			return ret;
-
 		port->uartclk = clk_get_rate(uart->clk);
 	}
 
@@ -115,7 +111,6 @@ static int tegra_uart_probe(struct platform_device *pdev)
 err_ctrl_assert:
 	reset_control_assert(uart->rst);
 err_clkdisable:
-	clk_disable_unprepare(uart->clk);
 
 	return ret;
 }
@@ -126,7 +121,6 @@ static void tegra_uart_remove(struct platform_device *pdev)
 
 	serial8250_unregister_port(uart->line);
 	reset_control_assert(uart->rst);
-	clk_disable_unprepare(uart->clk);
 }
 
 #ifdef CONFIG_PM_SLEEP
-- 
2.34.1

Re: [PATCH 2/8] tty: 8250_tegra: Use devm_clk_get_enabled() helpers

[Andy Shevchenko]

On Thu, Aug 22, 2024 at 11:39:06AM +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().

...

>  err_clkdisable:
> -	clk_disable_unprepare(uart->clk);
>  
>  	return ret;

Now this label (err_clkdisable) becomes redundant and code may use return ret
in-line.

-- 
With Best Regards,
Andy Shevchenko

[PATCH 3/8] tty: 8250_uniphier: Use devm_clk_get_enabled() helpers

[Lei Liu]

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/8250/8250_uniphier.c | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_uniphier.c b/drivers/tty/serial/8250/8250_uniphier.c
index 670d2ca0f757..6ddc4262d22b 100644
--- a/drivers/tty/serial/8250/8250_uniphier.c
+++ b/drivers/tty/serial/8250/8250_uniphier.c
@@ -180,16 +180,12 @@ static int uniphier_uart_probe(struct platform_device *pdev)
 
 	memset(&up, 0, sizeof(up));
 
-	priv->clk = devm_clk_get(dev, NULL);
+	priv->clk = devm_clk_get_enabled(dev, NULL);
 	if (IS_ERR(priv->clk)) {
 		dev_err(dev, "failed to get clock\n");
 		return PTR_ERR(priv->clk);
 	}
 
-	ret = clk_prepare_enable(priv->clk);
-	if (ret)
-		return ret;
-
 	up.port.uartclk = clk_get_rate(priv->clk);
 
 	spin_lock_init(&priv->atomic_write_lock);
@@ -222,7 +218,6 @@ static int uniphier_uart_probe(struct platform_device *pdev)
 	ret = serial8250_register_8250_port(&up);
 	if (ret < 0) {
 		dev_err(dev, "failed to register 8250 port\n");
-		clk_disable_unprepare(priv->clk);
 		return ret;
 	}
 	priv->line = ret;
@@ -237,7 +232,6 @@ static void uniphier_uart_remove(struct platform_device *pdev)
 	struct uniphier8250_priv *priv = platform_get_drvdata(pdev);
 
 	serial8250_unregister_port(priv->line);
-	clk_disable_unprepare(priv->clk);
 }
 
 static int __maybe_unused uniphier_uart_suspend(struct device *dev)
-- 
2.34.1

[PATCH 4/8] tty: atmel_serial: Use devm_clk_get_enabled() helpers

[Lei Liu]

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/atmel_serial.c | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
index 09b246c9e389..209f3d41a17c 100644
--- a/drivers/tty/serial/atmel_serial.c
+++ b/drivers/tty/serial/atmel_serial.c
@@ -2910,14 +2910,11 @@ static int atmel_serial_probe(struct platform_device *pdev)
 	atomic_set(&atmel_port->tasklet_shutdown, 0);
 	spin_lock_init(&atmel_port->lock_suspended);
 
-	atmel_port->clk = devm_clk_get(&pdev->dev, "usart");
+	atmel_port->clk = devm_clk_get_enabled(&pdev->dev, "usart");
 	if (IS_ERR(atmel_port->clk)) {
 		ret = PTR_ERR(atmel_port->clk);
 		goto err;
 	}
-	ret = clk_prepare_enable(atmel_port->clk);
-	if (ret)
-		goto err;
 
 	atmel_port->gclk = devm_clk_get_optional(&pdev->dev, "gclk");
 	if (IS_ERR(atmel_port->gclk)) {
@@ -2968,15 +2965,12 @@ static int atmel_serial_probe(struct platform_device *pdev)
 	 * The peripheral clock can now safely be disabled till the port
 	 * is used
 	 */
-	clk_disable_unprepare(atmel_port->clk);
-
 	return 0;
 
 err_add_port:
 	kfree(atmel_port->rx_ring.buf);
 	atmel_port->rx_ring.buf = NULL;
 err_clk_disable_unprepare:
-	clk_disable_unprepare(atmel_port->clk);
 	clear_bit(atmel_port->uart.line, atmel_ports_in_use);
 err:
 	return ret;
-- 
2.34.1

Re: [PATCH 4/8] tty: atmel_serial: Use devm_clk_get_enabled() helpers

[Richard GENOUD]

Le 22/08/2024 à 05:39, Lei Liu a écrit :
> 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/atmel_serial.c | 8 +-------
>   1 file changed, 1 insertion(+), 7 deletions(-)
> 
> diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
> index 09b246c9e389..209f3d41a17c 100644
> --- a/drivers/tty/serial/atmel_serial.c
> +++ b/drivers/tty/serial/atmel_serial.c
> @@ -2910,14 +2910,11 @@ static int atmel_serial_probe(struct platform_device *pdev)
>   	atomic_set(&atmel_port->tasklet_shutdown, 0);
>   	spin_lock_init(&atmel_port->lock_suspended);
>   
> -	atmel_port->clk = devm_clk_get(&pdev->dev, "usart");
> +	atmel_port->clk = devm_clk_get_enabled(&pdev->dev, "usart");
>   	if (IS_ERR(atmel_port->clk)) {
>   		ret = PTR_ERR(atmel_port->clk);
>   		goto err;
>   	}
> -	ret = clk_prepare_enable(atmel_port->clk);
> -	if (ret)
> -		goto err;
>   
>   	atmel_port->gclk = devm_clk_get_optional(&pdev->dev, "gclk");
>   	if (IS_ERR(atmel_port->gclk)) {
> @@ -2968,15 +2965,12 @@ static int atmel_serial_probe(struct platform_device *pdev)
>   	 * The peripheral clock can now safely be disabled till the port
>   	 * is used
>   	 */
> -	clk_disable_unprepare(atmel_port->clk);
> -
Why removing this ?
This is not an error path.

>   	return 0;
>   
>   err_add_port:
>   	kfree(atmel_port->rx_ring.buf);
>   	atmel_port->rx_ring.buf = NULL;
>   err_clk_disable_unprepare:
> -	clk_disable_unprepare(atmel_port->clk);
>   	clear_bit(atmel_port->uart.line, atmel_ports_in_use);
>   err:
>   	return ret;

Thanks,
Richard.

Re: [PATCH 4/8] tty: atmel_serial: Use devm_clk_get_enabled() helpers

[Andy Shevchenko]

On Thu, Aug 22, 2024 at 03:28:40PM +0200, Richard GENOUD wrote:
> Le 22/08/2024 à 05:39, Lei Liu a écrit :
> > 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().

...

> >   	 * The peripheral clock can now safely be disabled till the port
> >   	 * is used
> >   	 */
> > -	clk_disable_unprepare(atmel_port->clk);
> > -
> Why removing this ?
> This is not an error path.

Good point, I wouldn't apply this patch as well as a few others in this series
due to this reason.

Instead it might make sense to add a comment on top of devm_clk_get() to
explain why _enabled() variant is *not* used.

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH 4/8] tty: atmel_serial: Use devm_clk_get_enabled() helpers

[Alexandre Belloni]

On 22/08/2024 16:34:28+0300, Andy Shevchenko wrote:
> On Thu, Aug 22, 2024 at 03:28:40PM +0200, Richard GENOUD wrote:
> > Le 22/08/2024 à 05:39, Lei Liu a écrit :
> > > 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().
> 
> ...
> 
> > >   	 * The peripheral clock can now safely be disabled till the port
> > >   	 * is used
> > >   	 */
> > > -	clk_disable_unprepare(atmel_port->clk);
> > > -
> > Why removing this ?
> > This is not an error path.
> 
> Good point, I wouldn't apply this patch as well as a few others in this series
> due to this reason.
> 
> Instead it might make sense to add a comment on top of devm_clk_get() to
> explain why _enabled() variant is *not* used.

Or maybe stop doing brainded conversions to new APIs.

> 
> -- 
> With Best Regards,
> Andy Shevchenko
> 
> 

-- 
Alexandre Belloni, co-owner and COO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

[PATCH 5/8] tty: mps2-uart: Use devm_clk_get_enabled() helpers

[Lei Liu]

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

Re: [PATCH 5/8] tty: mps2-uart: Use devm_clk_get_enabled() helpers

[Andy Shevchenko]

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

Re: [PATCH 5/8] tty: mps2-uart: Use devm_clk_get_enabled() helpers

[Lei Liu]

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

[PATCH 6/8] tty: owl-uart: Use devm_clk_get_enabled() helpers

[Lei Liu]

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/owl-uart.c | 10 +---------
 1 file changed, 1 insertion(+), 9 deletions(-)

diff --git a/drivers/tty/serial/owl-uart.c b/drivers/tty/serial/owl-uart.c
index ecec483d4d59..28c33cea6b41 100644
--- a/drivers/tty/serial/owl-uart.c
+++ b/drivers/tty/serial/owl-uart.c
@@ -680,18 +680,12 @@ static int owl_uart_probe(struct platform_device *pdev)
 	if (!owl_port)
 		return -ENOMEM;
 
-	owl_port->clk = devm_clk_get(&pdev->dev, NULL);
+	owl_port->clk = devm_clk_get_enabled(&pdev->dev, NULL);
 	if (IS_ERR(owl_port->clk)) {
 		dev_err(&pdev->dev, "could not get clk\n");
 		return PTR_ERR(owl_port->clk);
 	}
 
-	ret = clk_prepare_enable(owl_port->clk);
-	if (ret) {
-		dev_err(&pdev->dev, "could not enable clk\n");
-		return ret;
-	}
-
 	owl_port->port.dev = &pdev->dev;
 	owl_port->port.line = pdev->id;
 	owl_port->port.type = PORT_OWL;
@@ -701,7 +695,6 @@ static int owl_uart_probe(struct platform_device *pdev)
 	owl_port->port.uartclk = clk_get_rate(owl_port->clk);
 	if (owl_port->port.uartclk == 0) {
 		dev_err(&pdev->dev, "clock rate is zero\n");
-		clk_disable_unprepare(owl_port->clk);
 		return -EINVAL;
 	}
 	owl_port->port.flags = UPF_BOOT_AUTOCONF | UPF_IOREMAP | UPF_LOW_LATENCY;
@@ -725,7 +718,6 @@ static void owl_uart_remove(struct platform_device *pdev)
 
 	uart_remove_one_port(&owl_uart_driver, &owl_port->port);
 	owl_uart_ports[pdev->id] = NULL;
-	clk_disable_unprepare(owl_port->clk);
 }
 
 static struct platform_driver owl_uart_platform_driver = {
-- 
2.34.1

[PATCH 7/8] tty: st-asc: Use devm_clk_get_enabled() helpers

[Lei Liu]

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/st-asc.c | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/drivers/tty/serial/st-asc.c b/drivers/tty/serial/st-asc.c
index f91753a40a69..df666766d50e 100644
--- a/drivers/tty/serial/st-asc.c
+++ b/drivers/tty/serial/st-asc.c
@@ -706,17 +706,13 @@ static int asc_init_port(struct asc_port *ascport,
 
 	spin_lock_init(&port->lock);
 
-	ascport->clk = devm_clk_get(&pdev->dev, NULL);
+	ascport->clk = devm_clk_get_enabled(&pdev->dev, NULL);
 
 	if (WARN_ON(IS_ERR(ascport->clk)))
 		return -EINVAL;
-	/* ensure that clk rate is correct by enabling the clk */
-	ret = clk_prepare_enable(ascport->clk);
-	if (ret)
-		return ret;
+
 	ascport->port.uartclk = clk_get_rate(ascport->clk);
 	WARN_ON(ascport->port.uartclk == 0);
-	clk_disable_unprepare(ascport->clk);
 
 	ascport->pinctrl = devm_pinctrl_get(&pdev->dev);
 	if (IS_ERR(ascport->pinctrl)) {
-- 
2.34.1

Re: [PATCH 7/8] tty: st-asc: Use devm_clk_get_enabled() helpers

[Andy Shevchenko]

On Thu, Aug 22, 2024 at 11:39:11AM +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().

...

Same caveat as in another patch comment.

> -	ascport->clk = devm_clk_get(&pdev->dev, NULL);
> +	ascport->clk = devm_clk_get_enabled(&pdev->dev, NULL);
>  
>  	if (WARN_ON(IS_ERR(ascport->clk)))
>  		return -EINVAL;
> -	/* ensure that clk rate is correct by enabling the clk */
> -	ret = clk_prepare_enable(ascport->clk);
> -	if (ret)
> -		return ret;
> +
>  	ascport->port.uartclk = clk_get_rate(ascport->clk);

>  	WARN_ON(ascport->port.uartclk == 0);

Btw, not related to this series, you may try to get rid of these 0 checks as
the serial core has this and it will fail anyway. Perhaps you want to expand
serial core to issue an error message (if it's not done yet).

> -	clk_disable_unprepare(ascport->clk);

-- 
With Best Regards,
Andy Shevchenko

[PATCH 8/8] tty: stm32-usart: Use devm_clk_get_enabled() helpers

[Lei Liu]

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/stm32-usart.c | 16 +---------------
 1 file changed, 1 insertion(+), 15 deletions(-)

diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c
index e1e7bc04c579..9bce3159165a 100644
--- a/drivers/tty/serial/stm32-usart.c
+++ b/drivers/tty/serial/stm32-usart.c
@@ -1550,11 +1550,6 @@ static int stm32_usart_get_ftcfg(struct platform_device *pdev, struct stm32_port
 	return fifo_size;
 }
 
-static void stm32_usart_deinit_port(struct stm32_port *stm32port)
-{
-	clk_disable_unprepare(stm32port->clk);
-}
-
 static const struct serial_rs485 stm32_rs485_supported = {
 	.flags = SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | SER_RS485_RTS_AFTER_SEND |
 		 SER_RS485_RX_DURING_TX,
@@ -1599,15 +1594,10 @@ static int stm32_usart_init_port(struct stm32_port *stm32port,
 
 	spin_lock_init(&port->lock);
 
-	stm32port->clk = devm_clk_get(&pdev->dev, NULL);
+	stm32port->clk = devm_clk_get_enabled(&pdev->dev, NULL);
 	if (IS_ERR(stm32port->clk))
 		return PTR_ERR(stm32port->clk);
 
-	/* Ensure that clk rate is correct by enabling the clk */
-	ret = clk_prepare_enable(stm32port->clk);
-	if (ret)
-		return ret;
-
 	stm32port->port.uartclk = clk_get_rate(stm32port->clk);
 	if (!stm32port->port.uartclk) {
 		ret = -EINVAL;
@@ -1645,7 +1635,6 @@ static int stm32_usart_init_port(struct stm32_port *stm32port,
 	return ret;
 
 err_clk:
-	clk_disable_unprepare(stm32port->clk);
 
 	return ret;
 }
@@ -1853,8 +1842,6 @@ static int stm32_usart_serial_probe(struct platform_device *pdev)
 	if (stm32port->wakeup_src)
 		device_set_wakeup_capable(&pdev->dev, false);
 
-	stm32_usart_deinit_port(stm32port);
-
 err_dma_tx:
 	if (stm32port->tx_ch)
 		dma_release_channel(stm32port->tx_ch);
@@ -1904,7 +1891,6 @@ static void stm32_usart_serial_remove(struct platform_device *pdev)
 		device_init_wakeup(&pdev->dev, false);
 	}
 
-	stm32_usart_deinit_port(stm32_port);
 }
 
 static void __maybe_unused stm32_usart_console_putchar(struct uart_port *port, unsigned char ch)
-- 
2.34.1

Re: [PATCH 8/8] tty: stm32-usart: Use devm_clk_get_enabled() helpers

[Andy Shevchenko]

On Thu, Aug 22, 2024 at 11:39:12AM +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().

...

>  err_clk:
> -	clk_disable_unprepare(stm32port->clk);
>  
>  	return ret;

No unneeded label, please drop it as well and return directly.

-- 
With Best Regards,
Andy Shevchenko