Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Subject: Re: [PATCH] staging: nvec: Fix usleep_range is preferred over udelay
To:     Joshua Abraham <j.abraham1776@gmail.com>, marvin24@gmx.de
Cc:     gregkh@linuxfoundation.org, ac100@lists.launchpad.net,
        linux-tegra@vger.kernel.org, devel@driverdev.osuosl.org,
        linux-kernel@vger.kernel.org
References: <20171129160002.GA26462@josharch>
From:   Mikko Perttunen <cyndis@kapsi.fi>
Message-ID: <78551ca3-9ebe-3010-f856-46026f9ce9a3@kapsi.fi>
Date:   Wed, 29 Nov 2017 18:07:53 +0200
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101
 Thunderbird/52.3.0
MIME-Version: 1.0
In-Reply-To: <20171129160002.GA26462@josharch>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On 11/29/2017 06:00 PM, Joshua Abraham wrote:
> Signed-off-by: Joshua Abraham <j.abraham1776@gmail.com>
> 
> This patch fixes the issue:
> 
> CHECK: usleep_range is preferred over udelay; see
> Documentation/timers/timers-howto.txt
> 
> ---
>   drivers/staging/nvec/nvec.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/staging/nvec/nvec.c b/drivers/staging/nvec/nvec.c
> index 4ff8f47385da..2a01ef4b54ff 100644
> --- a/drivers/staging/nvec/nvec.c
> +++ b/drivers/staging/nvec/nvec.c
> @@ -631,7 +631,7 @@ static irqreturn_t nvec_interrupt(int irq, void *dev)
>   		break;
>   	case 2:		/* first byte after command */
>   		if (status == (I2C_SL_IRQ | RNW | RCVD)) {
> -			udelay(33);
> +			usleep_range(30, 35);
>   			if (nvec->rx->data[0] != 0x01) {
>   				dev_err(nvec->dev,
>   					"Read without prior read command\n");
> 

This is incorrect, as this function is an interrupt handler and we 
cannot sleep in interrupt context.

Cheers,
Mikko

From 1586046313102807327@xxx Wed Dec 06 14:47:13 +0000 2017
X-GM-THRID: 1586046313102807327
X-Gmail-Labels: Inbox,Category Forums,HistoricalUnread