linux-kernel - Re: [PATCH v2] serial: 8250_of: Add basic PM runtime support

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Message-ID: <6fcea218-1025-7563-6a70-b7c66713311b@lechnology.com>
Date:   Wed, 9 Aug 2017 18:09:02 -0500
From:   David Lechner <david@...hnology.com>
To:     Franklin S Cooper Jr <fcooper@...com>, gregkh@...uxfoundation.org,
        jslaby@...e.com, linux-serial@...r.kernel.org,
        linux-kernel@...r.kernel.org, vigneshr@...com, joel@....id.au,
        khoroshilov@...ras.ru, arnd@...db.de, robert.jarzmik@...e.fr,
        tthayer@...nsource.altera.com
Subject: Re: [PATCH v2] serial: 8250_of: Add basic PM runtime support

On 08/07/2017 03:46 PM, Franklin S Cooper Jr wrote:
> Add basic PM Runtime support.
> 
> Signed-off-by: Franklin S Cooper Jr <fcooper@...com>
> ---
> 
> Version 2 changes:
> Fix build error.
> Build tested using allmodconfig
> 
>   drivers/tty/serial/8250/8250_of.c | 35 ++++++++++++++++++++++++-----------
>   1 file changed, 24 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/tty/serial/8250/8250_of.c b/drivers/tty/serial/8250/8250_of.c
> index 6c5a8ca..9bad8bae 100644
> --- a/drivers/tty/serial/8250/8250_of.c
> +++ b/drivers/tty/serial/8250/8250_of.c
> @@ -18,6 +18,7 @@
>   #include <linux/of_address.h>
>   #include <linux/of_irq.h>
>   #include <linux/of_platform.h>
> +#include <linux/pm_runtime.h>
>   #include <linux/clk.h>
>   #include <linux/reset.h>
>   
> @@ -65,6 +66,10 @@ static int of_platform_serial_setup(struct platform_device *ofdev,
>   	int ret;
>   
>   	memset(port, 0, sizeof *port);
> +
> +	pm_runtime_enable(&ofdev->dev);
> +	pm_runtime_get_sync(&ofdev->dev);
> +
>   	if (of_property_read_u32(np, "clock-frequency", &clk)) {
>   
>   		/* Get clk rate through clk driver if present */
> @@ -72,12 +77,13 @@ static int of_platform_serial_setup(struct platform_device *ofdev,
>   		if (IS_ERR(info->clk)) {
>   			dev_warn(&ofdev->dev,
>   				"clk or clock-frequency not defined\n");
> -			return PTR_ERR(info->clk);
> +			ret = PTR_ERR(info->clk);
> +			goto err_pmruntime;
>   		}
>   
>   		ret = clk_prepare_enable(info->clk);
>   		if (ret < 0)
> -			return ret;
> +			goto err_pmruntime;
>   
>   		clk = clk_get_rate(info->clk);
>   	}
> @@ -170,8 +176,10 @@ static int of_platform_serial_setup(struct platform_device *ofdev,
>   err_dispose:
>   	irq_dispose_mapping(port->irq);
>   err_unprepare:
> -	if (info->clk)
> -		clk_disable_unprepare(info->clk);
> +	clk_disable_unprepare(info->clk);
> +err_pmruntime:
> +	pm_runtime_put_sync(&ofdev->dev);
> +	pm_runtime_disable(&ofdev->dev);
>   	return ret;
>   }
>   
> @@ -227,8 +235,9 @@ static int of_platform_serial_probe(struct platform_device *ofdev)
>   	return 0;
>   err_dispose:
>   	irq_dispose_mapping(port8250.port.irq);
> -	if (info->clk)
> -		clk_disable_unprepare(info->clk);
> +	pm_runtime_put_sync(&ofdev->dev);
> +	pm_runtime_disable(&ofdev->dev);
> +	clk_disable_unprepare(info->clk);
>   err_free:
>   	kfree(info);
>   	return ret;
> @@ -244,8 +253,9 @@ static int of_platform_serial_remove(struct platform_device *ofdev)
>   	serial8250_unregister_port(info->line);
>   
>   	reset_control_assert(info->rst);
> -	if (info->clk)
> -		clk_disable_unprepare(info->clk);
> +	pm_runtime_put_sync(&ofdev->dev);
> +	pm_runtime_disable(&ofdev->dev);
> +	clk_disable_unprepare(info->clk);
>   	kfree(info);
>   	return 0;
>   }
> @@ -259,9 +269,10 @@ static int of_serial_suspend(struct device *dev)
>   
>   	serial8250_suspend_port(info->line);
>   
> -	if (info->clk && (!uart_console(port) || console_suspend_enabled))
> +	if ((!uart_console(port) || console_suspend_enabled)) {

Extra pair of parenthesis can be removed. ^

> +		pm_runtime_put_sync(dev);
>   		clk_disable_unprepare(info->clk);
> -
> +	}
>   	return 0;
>   }
>   
> @@ -271,8 +282,10 @@ static int of_serial_resume(struct device *dev)
>   	struct uart_8250_port *port8250 = serial8250_get_port(info->line);
>   	struct uart_port *port = &port8250->port;
>   
> -	if (info->clk && (!uart_console(port) || console_suspend_enabled))
> +	if ((!uart_console(port) || console_suspend_enabled)) {

Extra pair of parenthesis can be removed. ^

> +		pm_runtime_get_sync(dev);
>   		clk_prepare_enable(info->clk);
> +	}
>   
>   	serial8250_resume_port(info->line);
>   
>