linux-kernel - Re: [PATCH v2] b43: Replace mdelay with usleep_range in b43_radio_2057_init

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Message-ID: <05e5756d-e401-5584-f809-e3ad42db2a66@lwfinger.net>
Date:   Tue, 9 Jan 2018 10:49:58 -0600
From:   Larry Finger <Larry.Finger@...inger.net>
To:     Jia-Ju Bai <baijiaju1990@...il.com>, kvalo@...eaurora.org,
        kstewart@...uxfoundation.org, johannes.berg@...el.com,
        tiwai@...e.de, gregkh@...uxfoundation.org,
        colin.king@...onical.com, andrew.zaborowski@...el.com
Cc:     linux-kernel@...r.kernel.org, linux-wireless@...r.kernel.org,
        netdev@...r.kernel.org, b43-dev@...ts.infradead.org
Subject: Re: [PATCH v2] b43: Replace mdelay with usleep_range in
 b43_radio_2057_init_post

On 01/08/2018 07:40 PM, Jia-Ju Bai wrote:
> b43_radio_2057_init_post is not called in an interrupt handler
> nor holding a spinlock.
> The function mdelay in it can be replaced with usleep_range,
> to reduce busy wait.
> 
> Signed-off-by: Jia-Ju Bai <baijiaju1990@...il.com>
> ---
> v2:
> * Replace mdelay with usleep_range, instead of msleep in v1.
>    Thank Larry for good advice.
> ---

I agree that a sleep of 2-3 ms should be OK here.

Acked-by: Larry Finger <Larry.Finger@...inger.net>

Larry

>   drivers/net/wireless/broadcom/b43/phy_n.c |    2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/wireless/broadcom/b43/phy_n.c b/drivers/net/wireless/broadcom/b43/phy_n.c
> index a5557d7..f2a2f41 100644
> --- a/drivers/net/wireless/broadcom/b43/phy_n.c
> +++ b/drivers/net/wireless/broadcom/b43/phy_n.c
> @@ -1031,7 +1031,7 @@ static void b43_radio_2057_init_post(struct b43_wldev *dev)
>   
>   	b43_radio_set(dev, R2057_RFPLL_MISC_CAL_RESETN, 0x78);
>   	b43_radio_set(dev, R2057_XTAL_CONFIG2, 0x80);
> -	mdelay(2);
> +	usleep_range(2000, 3000);
>   	b43_radio_mask(dev, R2057_RFPLL_MISC_CAL_RESETN, ~0x78);
>   	b43_radio_mask(dev, R2057_XTAL_CONFIG2, ~0x80);
>   
>