Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Message-ID: <1553152850.576.3.camel@mtksdaap41>
Subject: Re: [PATCH V6 8/8] drm/mediatek: fix the rate of parent for hdmi
 phy in MT2701
From:   CK Hu <ck.hu@mediatek.com>
To:     wangyan wang <wangyan.wang@mediatek.com>
CC:     Michael Turquette <mturquette@baylibre.com>,
        Stephen Boyd <sboyd@kernel.org>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        "Philipp Zabel" <p.zabel@pengutronix.de>,
        David Airlie <airlied@linux.ie>,
        "Daniel Vetter" <daniel@ffwll.ch>,
        chunhui dai <chunhui.dai@mediatek.com>,
        "Colin Ian King" <colin.king@canonical.com>,
        Sean Wang <sean.wang@mediatek.com>,
        "Ryder Lee" <ryder.lee@mediatek.com>, <linux-clk@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>,
        <linux-arm-kernel@lists.infradead.org>,
        <linux-mediatek@lists.infradead.org>,
        <dri-devel@lists.freedesktop.org>, <srv_heupstream@mediatek.com>
Date:   Thu, 21 Mar 2019 15:20:50 +0800
In-Reply-To: <1553146377.18216.30.camel@mtksdaap41>
References: <20190225020912.29120-1-wangyan.wang@mediatek.com>
         <20190225020912.29120-9-wangyan.wang@mediatek.com>
         <1551867194.1001.8.camel@mtksdaap41> <1553146377.18216.30.camel@mtksdaap41>
Content-Type: text/plain; charset="UTF-8"
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Hi, Wangyan:

On Thu, 2019-03-21 at 13:32 +0800, CK Hu wrote:
> Hi, Wangyan:
> 
> On Wed, 2019-03-06 at 18:13 +0800, CK Hu wrote:
> > Hi, Wangyan:
> > 
> > On Mon, 2019-02-25 at 10:09 +0800, wangyan wang wrote:
> > > From: chunhui dai <chunhui.dai@mediatek.com>
> > > 
> > > We should not change the rate of parent for hdmi phy when
> > > doing round_rate for this clock. The parent clock of hdmi
> > > phy must be the same as it. We change it when doing set_rate
> > > only.
> > > 
> > > Signed-off-by: chunhui dai <chunhui.dai@mediatek.com>
> > > Signed-off-by: wangyan wang <wangyan.wang@mediatek.com>
> > > ---
> > >  drivers/gpu/drm/mediatek/mtk_hdmi_phy.c        | 14 --------------
> > >  drivers/gpu/drm/mediatek/mtk_hdmi_phy.h        |  3 ---
> > >  drivers/gpu/drm/mediatek/mtk_mt2701_hdmi_phy.c | 11 +++++++++++
> > >  drivers/gpu/drm/mediatek/mtk_mt8173_hdmi_phy.c | 14 ++++++++++++++
> > >  4 files changed, 25 insertions(+), 17 deletions(-)
> > > 
> > > diff --git a/drivers/gpu/drm/mediatek/mtk_hdmi_phy.c b/drivers/gpu/drm/mediatek/mtk_hdmi_phy.c
> > > index 370309d684ec..ca8bc1489f37 100644
> > > --- a/drivers/gpu/drm/mediatek/mtk_hdmi_phy.c
> > > +++ b/drivers/gpu/drm/mediatek/mtk_hdmi_phy.c
> > > @@ -15,20 +15,6 @@ static const struct phy_ops mtk_hdmi_phy_dev_ops = {
> > >  	.owner = THIS_MODULE,
> > >  };
> > >  
> > > -long mtk_hdmi_pll_round_rate(struct clk_hw *hw, unsigned long rate,
> > > -			     unsigned long *parent_rate)
> > > -{
> > > -	struct mtk_hdmi_phy *hdmi_phy = to_mtk_hdmi_phy(hw);
> > > -
> > > -	hdmi_phy->pll_rate = rate;
> > > -	if (rate <= 74250000)
> > > -		*parent_rate = rate;
> > > -	else
> > > -		*parent_rate = rate / 2;
> > > -
> > > -	return rate;
> > > -}
> > > -
> > >  u32 mtk_hdmi_phy_read(struct mtk_hdmi_phy *hdmi_phy, u32 offset)
> > >  {
> > >  	return readl(hdmi_phy->regs + offset);
> > > diff --git a/drivers/gpu/drm/mediatek/mtk_hdmi_phy.h b/drivers/gpu/drm/mediatek/mtk_hdmi_phy.h
> > > index 446e2acd1926..c6061ad15ff0 100644
> > > --- a/drivers/gpu/drm/mediatek/mtk_hdmi_phy.h
> > > +++ b/drivers/gpu/drm/mediatek/mtk_hdmi_phy.h
> > > @@ -50,9 +50,6 @@ void mtk_hdmi_phy_set_bits(struct mtk_hdmi_phy *hdmi_phy, u32 offset,
> > >  void mtk_hdmi_phy_mask(struct mtk_hdmi_phy *hdmi_phy, u32 offset,
> > >  		       u32 val, u32 mask);
> > >  struct mtk_hdmi_phy *to_mtk_hdmi_phy(struct clk_hw *hw);
> > > -long mtk_hdmi_pll_round_rate(struct clk_hw *hw, unsigned long rate,
> > > -			     unsigned long *parent_rate);
> > > -
> > >  extern struct platform_driver mtk_hdmi_phy_driver;
> > >  extern struct mtk_hdmi_phy_conf mtk_hdmi_phy_8173_conf;
> > >  extern struct mtk_hdmi_phy_conf mtk_hdmi_phy_2701_conf;
> > > diff --git a/drivers/gpu/drm/mediatek/mtk_mt2701_hdmi_phy.c b/drivers/gpu/drm/mediatek/mtk_mt2701_hdmi_phy.c
> > > index 88dd9e812ca0..33893a180c2e 100644
> > > --- a/drivers/gpu/drm/mediatek/mtk_mt2701_hdmi_phy.c
> > > +++ b/drivers/gpu/drm/mediatek/mtk_mt2701_hdmi_phy.c
> > > @@ -152,6 +152,17 @@ static int mtk_hdmi_pll_set_rate(struct clk_hw *hw, unsigned long rate,
> > >  			  RG_HDMITX_DRV_IBIAS_MASK);
> > >  	return 0;
> > >  }
> > > +
> > > +static long mtk_hdmi_pll_round_rate(struct clk_hw *hw, unsigned long rate,
> > > +			     unsigned long *parent_rate)
> > > +{
> > > +	struct mtk_hdmi_phy *hdmi_phy = to_mtk_hdmi_phy(hw);
> > > +
> > > +	hdmi_phy->pll_rate = rate;
> > 
> > I think you don't need to save the rate into pll_rate here, pll_rate
> > would be set in set_rate() or recalc_rate().
> 
> As offline discuss, you mention that this function just need to return
> current rate. I think you could just remove this line
> 'hdmi_phy->pll_rate = rate;' and return rate only. You don't need to
> assign hdmi_phy->pll_rate here because it would be set later in
> set_rate().

If you do not do any thing in mtk_hdmi_pll_round_rate(), I think you
could just don't implement round_rate() callback function because ccf
would not call round_rate() if it is not implemented.

Regards,
CK

> 
> Regards,
> CK
> 
> > 
> > Regards,
> > CK
> > 
> > > +
> > > +	return rate;
> > > +}
> > > +
> > >  static unsigned long mtk_hdmi_pll_recalc_rate(struct clk_hw *hw,
> > >  				       unsigned long parent_rate)
> > >  {
> > > diff --git a/drivers/gpu/drm/mediatek/mtk_mt8173_hdmi_phy.c b/drivers/gpu/drm/mediatek/mtk_mt8173_hdmi_phy.c
> > > index 63dde42521b8..3a339f516613 100644
> > > --- a/drivers/gpu/drm/mediatek/mtk_mt8173_hdmi_phy.c
> > > +++ b/drivers/gpu/drm/mediatek/mtk_mt8173_hdmi_phy.c
> > > @@ -285,6 +285,20 @@ static int mtk_hdmi_pll_set_rate(struct clk_hw *hw, unsigned long rate,
> > >  	return 0;
> > >  }
> > >  
> > > +static long mtk_hdmi_pll_round_rate(struct clk_hw *hw, unsigned long rate,
> > > +			     unsigned long *parent_rate)
> > > +{
> > > +	struct mtk_hdmi_phy *hdmi_phy = to_mtk_hdmi_phy(hw);
> > > +
> > > +	hdmi_phy->pll_rate = rate;
> > > +	if (rate <= 74250000)
> > > +		*parent_rate = rate;
> > > +	else
> > > +		*parent_rate = rate / 2;
> > > +
> > > +	return rate;
> > > +}
> > > +
> > >  static unsigned long mtk_hdmi_pll_recalc_rate(struct clk_hw *hw,
> > >  				       unsigned long parent_rate)
> > >  {
> > 
>