From mboxrd@z Thu Jan  1 00:00:00 1970
From: arnd@arndb.de (Arnd Bergmann)
Date: Fri, 08 Jan 2016 09:26:10 +0100
Subject: [RFC PATCH 2/2] usb: Example for how to use device node at usb
 device driver
In-Reply-To: <1452231864-11171-3-git-send-email-peter.chen@freescale.com>
References: <1452231864-11171-1-git-send-email-peter.chen@freescale.com>
 <1452231864-11171-3-git-send-email-peter.chen@freescale.com>
Message-ID: <4231421.FQCAATyWeB@wuerfel>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Friday 08 January 2016 13:44:24 Peter Chen wrote:
> +	  u32 duration_us = 0;

> +       of_property_read_u32(hdev->dev.of_node, "delay-duration-us", &duration_us);
> +       if (duration_us > 0) {
> +               usleep_range(duration_us, duration_us + 10);
> +               dev_info(&hdev->dev, "The delay is %d us\n", duration_us);
> +       }
> +

I think especially for an example, it would be better to use error checking and
not initialize the variable:

	u32 duration_us;
	int ret;
...
	ret = of_property_read_u32(hdev->dev.of_node, "delay-duration-us", &duration_us);
	if (!ret && duration_us > 0) {
		...
	}

The effect is the same as the other one.

	Arnd