Re: [PATCH] mmc: Add a restriction to mmc debugfs clock setting.

[Shawn Lin <shawn.lin@rock-chips.com>]

On 2016/1/19 14:44, Wodkowski, PawelX wrote:
>> -----Original Message-----
>> From: linux-mmc-owner@vger.kernel.org [mailto:linux-mmc-
>> owner@vger.kernel.org] On Behalf Of Shawn Lin
>> Sent: Tuesday, January 19, 2016 7:35 AM
>> To: Wodkowski, PawelX <pawelx.wodkowski@intel.com>; linux-
>> mmc@vger.kernel.org
>> Cc: shawn.lin@rock-chips.com; Dong, Chuanxiao
>> <chuanxiao.dong@intel.com>; Yuan, Juntao <juntao.yuan@intel.com>
>> Subject: Re: [PATCH] mmc: Add a restriction to mmc debugfs clock setting.
>>
>> On 2016/1/19 14:13, Pawel Wodkowski wrote:
>>> From: Chuanxiao Dong <chuanxiao.dong@intel.com>
>>>
>>> Clock frequency values written to an mmc host should not be less than
>>> the minimum clock frequency which the mmc host supports.
>>>
>>> Signed-off-by: Yuan Juntao <juntaox.yuan@intel.com>
>>> Signed-off-by: Pawel Wodkowski <pawelx.wodkowski@intel.com>
>>> ---
>>>    drivers/mmc/core/debugfs.c | 2 +-
>>>    1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/mmc/core/debugfs.c b/drivers/mmc/core/debugfs.c
>>> index 154aced0b91b..bdfce774d848 100644
>>> --- a/drivers/mmc/core/debugfs.c
>>> +++ b/drivers/mmc/core/debugfs.c
>>> @@ -220,7 +220,7 @@ static int mmc_clock_opt_set(void *data, u64
>> val)
>>>    	struct mmc_host *host = data;
>>>
>>>    	/* We need this check due to input value is u64 */
>>> -	if (val > host->f_max)
>>> +	if (val > host->f_max || val < host->f_min)
>>
>> Hmm... how about if I want to disable clk from sysfs and pass ZERO to
>> mmc_clock_opt_set, doesn't that case make sense? :)
>>
>
> So maybe something like this?
> if (val != 0 && (val > host->f_max || val < host->f_min))

yep.

>


-- 
Best Regards
Shawn Lin