From mboxrd@z Thu Jan 1 00:00:00 1970 From: biao huang Subject: Re: [PATCH 2/6] net: stmmac: fix csr_clk can't be zero issue Date: Mon, 29 Apr 2019 16:09:13 +0800 Message-ID: <1556525353.24897.30.camel@mhfsdcap03> 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> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <24f4b268-aa7f-e1f7-59fc-2bc163eb8277@st.com> Sender: linux-kernel-owner@vger.kernel.org To: Alexandre Torgue Cc: Jose Abreu , davem@davemloft.net, Giuseppe Cavallaro , Maxime Coquelin , Matthias Brugger , netdev@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mediatek@lists.infradead.org, yt.shen@mediatek.com, jianguo.zhang@mediatek.com List-Id: linux-mediatek@lists.infradead.org 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. In some case, it's impossible to get the clk rate of stmmac_clk, so it's better to remain the clk_csr flow.