lkml.org 
[lkml]   [2019]   [Apr]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH 2/6] net: stmmac: fix csr_clk can't be zero issue
From
Date


On 4/29/19 10:09 AM, biao huang wrote:
> Hi,
>
> On Mon, 2019-04-29 at 09:18 +0200, Alexandre Torgue wrote:
>> Hi
>>
>> On 4/28/19 8:30 AM, Biao Huang wrote:
>>> The specific clk_csr value can be zero, and
>>> stmmac_clk is necessary for MDC clock which can be set dynamically.
>>> So, change the condition from plat->clk_csr to plat->stmmac_clk to
>>> fix clk_csr can't be zero issue.
>>>
>>> Signed-off-by: Biao Huang <biao.huang@mediatek.com>
>>> ---
>>> drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 2 +-
>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
>>> index 818ad88..9e89b94 100644
>>> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
>>> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
>>> @@ -4376,7 +4376,7 @@ int stmmac_dvr_probe(struct device *device,
>>> * set the MDC clock dynamically according to the csr actual
>>> * clock input.
>>> */
>>> - if (!priv->plat->clk_csr)
>>> + if (priv->plat->stmmac_clk)
>>> stmmac_clk_csr_set(priv);
>>> else
>>> priv->clk_csr = priv->plat->clk_csr;
>>>
>>
>> So, as soon as stmmac_clk will be declared, it is no longer possible to
>> fix a CSR through the device tree ?
>
> let's focus on the condition:
> 1. clk_csr may be zero, it should not be the condition. or the clk_csr =
> 0 will jump to the wrong block.
> 2. Since stmmac_clk_csr_set will get_clk_rate from stmmac_clk,
> the plat->stmmac_clk is a more proper condition.
>

Ok, but here you remove one possibility: stmmac_clk and clk_csr defined.
no ?

Other way could be the following code + initialize priv->plat->clk_csr
with a non null value before read it in device tree (in stmmac_platform).

if (priv->plat->clk_csr >= 0)
priv->clk_csr = priv->plat->clk_csr;
else
stmmac_clk_csr_set(priv);



> In some case, it's impossible to get the clk rate of stmmac_clk,
> so it's better to remain the clk_csr flow.
>
>
>

\
 
 \ /
  Last update: 2019-04-29 10:28    [W:0.209 / U:0.684 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site