From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexandre Torgue Subject: Re: [PATCH 2/6] net: stmmac: fix csr_clk can't be zero issue Date: Mon, 29 Apr 2019 10:26:52 +0200 Message-ID: <738b37cd-4719-9257-18fc-aab1dc7424f4@st.com> References: <1556433009-25759-1-git-send-email-biao.huang@mediatek.com> <1556433009-25759-3-git-send-email-biao.huang@mediatek.com> <24f4b268-aa7f-e1f7-59fc-2bc163eb8277@st.com> <1556525353.24897.30.camel@mhfsdcap03> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1556525353.24897.30.camel@mhfsdcap03> Content-Language: en-US List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: biao huang Cc: jianguo.zhang@mediatek.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com, yt.shen@mediatek.com, Jose Abreu , linux-mediatek@lists.infradead.org, Maxime Coquelin , Matthias Brugger , Giuseppe Cavallaro , davem@davemloft.net, linux-arm-kernel@lists.infradead.org List-Id: linux-mediatek@lists.infradead.org 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 >>> --- >>> 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. > > >