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From: wwang <wei_wang@realsil.com.cn>
To: Dan Carpenter <dan.carpenter@oracle.com>
Cc: cjb@laptop.org, sameo@linux.intel.com,
	gregkh@linuxfoundation.org, linux-mmc@vger.kernel.org,
	linux-kernel@vger.kernel.org, rogerable@realtek.com,
	devel@linuxdriverproject.org
Subject: Re: [PATCH] mfd:rtsx: Support RTS5249
Date: Mon, 25 Mar 2013 14:23:45 +0800	[thread overview]
Message-ID: <514FED71.8020307@realsil.com.cn> (raw)
In-Reply-To: <20130325060038.GD9138@mwanda>

于 2013年03月25日 14:00, Dan Carpenter 写道:
> On Mon, Mar 25, 2013 at 10:13:56AM +0800, wei_wang@realsil.com.cn wrote:
>> +static int rts5249_optimize_phy(struct rtsx_pcr *pcr)
>> +{
>> +	int err;
>> +
>> +	err = rtsx_pci_write_phy_register(pcr, 0x19, 0xFE46);
>> +	if (err < 0)
>> +		return err;
>> +
>> +	mdelay(1);
> Why do we have the mdelay() and the later msleep(5)?
> rtsx_pci_write_phy_register() busy loops until the write succeeds or
> it returns -ETIMEOUT.  The extra wait here seems unnecessary.
>
> regards,
> dan carpenter
>
>
> .
>   

Hi,

The busy loops in rtsx_pci_write_phy_register only tell us that the 
write sequence succeeds. The device still needs to wait for a while 
until the internal signal stable. Or else the timing won't fit the 
requirement.
All of the delays in the driver are necessary.

BR,
Wei

  reply	other threads:[~2013-03-25  6:24 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-03-25  2:13 [PATCH] mfd:rtsx: Support RTS5249 wei_wang
2013-03-25  6:00 ` Dan Carpenter
2013-03-25  6:23   ` wwang [this message]
2013-03-25  6:29     ` Dan Carpenter
2013-04-09  9:49 ` Samuel Ortiz

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