Re: [PATCH v2 2/3] drm/mediatek: enhance the HDMI driving current

From: Philipp Zabel <p.zabel@pengutronix.de>
To: Bibby Hsieh <bibby.hsieh@mediatek.com>
Cc: David Airlie <airlied@linux.ie>,
	Matthias Brugger <matthias.bgg@gmail.com>,
	Daniel Vetter <daniel.vetter@ffwll.ch>,
	dri-devel@lists.freedesktop.org,
	linux-mediatek@lists.infradead.org,
	Yingjoe Chen <yingjoe.chen@mediatek.com>,
	Cawa Cheng <cawa.cheng@mediatek.com>,
	Daniel Kurtz <djkurtz@chromium.org>,
	YT Shen <yt.shen@mediatek.com>,
	Thierry Reding <thierry.reding@gmail.com>,
	CK Hu <ck.hu@mediatek.com>, Mao Huang <littlecvr@chromium.org>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org,
	Sascha Hauer <kernel@pengutronix.de>,
	Junzhi Zhao <junzhi.zhao@mediatek.com>
Subject: Re: [PATCH v2 2/3] drm/mediatek: enhance the HDMI driving current
Date: Wed, 27 Jul 2016 11:25:50 +0200	[thread overview]
Message-ID: <1469611550.2470.22.camel@pengutronix.de> (raw)
In-Reply-To: <1469608292-6106-3-git-send-email-bibby.hsieh@mediatek.com>

Am Mittwoch, den 27.07.2016, 16:31 +0800 schrieb Bibby Hsieh:
> From: Junzhi Zhao <junzhi.zhao@mediatek.com>
> 
> In order to improve 4K resolution performance,
> we have to enhance the HDMI driving currend
                                           ^
Typo, s/currend/current/

Besides that, this patch looks good to me.

regards
Philipp

> when clock rate is greater than 165MHz.
> 
> Signed-off-by: Junzhi Zhao <junzhi.zhao@mediatek.com>
> Signed-off-by: Bibby Hsieh <bibby.hsieh@mediatek.com>
> ---
>  drivers/gpu/drm/mediatek/mtk_mt8173_hdmi_phy.c |   42 +++++++++++++++++-------
>  1 file changed, 30 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_mt8173_hdmi_phy.c b/drivers/gpu/drm/mediatek/mtk_mt8173_hdmi_phy.c
> index 8a24754..51cb9cf 100644
> --- a/drivers/gpu/drm/mediatek/mtk_mt8173_hdmi_phy.c
> +++ b/drivers/gpu/drm/mediatek/mtk_mt8173_hdmi_phy.c
> @@ -265,6 +265,9 @@ static int mtk_hdmi_pll_set_rate(struct clk_hw *hw, unsigned long rate,
>  	struct mtk_hdmi_phy *hdmi_phy = to_mtk_hdmi_phy(hw);
>  	unsigned int pre_div;
>  	unsigned int div;
> +	unsigned int pre_ibias;
> +	unsigned int hdmi_ibias;
> +	unsigned int imp_en;
>  
>  	dev_dbg(hdmi_phy->dev, "%s: %lu Hz, parent: %lu Hz\n", __func__,
>  		rate, parent_rate);
> @@ -298,18 +301,31 @@ static int mtk_hdmi_pll_set_rate(struct clk_hw *hw, unsigned long rate,
>  			  (0x1 << PLL_BR_SHIFT),
>  			  RG_HDMITX_PLL_BP | RG_HDMITX_PLL_BC |
>  			  RG_HDMITX_PLL_BR);
> -	mtk_hdmi_phy_clear_bits(hdmi_phy, HDMI_CON3, RG_HDMITX_PRD_IMP_EN);
> +	if (rate < 165000000) {
> +		mtk_hdmi_phy_clear_bits(hdmi_phy, HDMI_CON3,
> +					RG_HDMITX_PRD_IMP_EN);
> +		pre_ibias = 0x3;
> +		imp_en = 0x0;
> +		hdmi_ibias = hdmi_phy->ibias;
> +	} else {
> +		mtk_hdmi_phy_set_bits(hdmi_phy, HDMI_CON3,
> +				      RG_HDMITX_PRD_IMP_EN);
> +		pre_ibias = 0x6;
> +		imp_en = 0xf;
> +		hdmi_ibias = hdmi_phy->ibias_up;
> +	}
>  	mtk_hdmi_phy_mask(hdmi_phy, HDMI_CON4,
> -			  (0x3 << PRD_IBIAS_CLK_SHIFT) |
> -			  (0x3 << PRD_IBIAS_D2_SHIFT) |
> -			  (0x3 << PRD_IBIAS_D1_SHIFT) |
> -			  (0x3 << PRD_IBIAS_D0_SHIFT),
> +			  (pre_ibias << PRD_IBIAS_CLK_SHIFT) |
> +			  (pre_ibias << PRD_IBIAS_D2_SHIFT) |
> +			  (pre_ibias << PRD_IBIAS_D1_SHIFT) |
> +			  (pre_ibias << PRD_IBIAS_D0_SHIFT),
>  			  RG_HDMITX_PRD_IBIAS_CLK |
>  			  RG_HDMITX_PRD_IBIAS_D2 |
>  			  RG_HDMITX_PRD_IBIAS_D1 |
>  			  RG_HDMITX_PRD_IBIAS_D0);
>  	mtk_hdmi_phy_mask(hdmi_phy, HDMI_CON3,
> -			  (0x0 << DRV_IMP_EN_SHIFT), RG_HDMITX_DRV_IMP_EN);
> +			  (imp_en << DRV_IMP_EN_SHIFT),
> +			  RG_HDMITX_DRV_IMP_EN);
>  	mtk_hdmi_phy_mask(hdmi_phy, HDMI_CON6,
>  			  (hdmi_phy->drv_imp_clk << DRV_IMP_CLK_SHIFT) |
>  			  (hdmi_phy->drv_imp_d2 << DRV_IMP_D2_SHIFT) |
> @@ -318,12 +334,14 @@ static int mtk_hdmi_pll_set_rate(struct clk_hw *hw, unsigned long rate,
>  			  RG_HDMITX_DRV_IMP_CLK | RG_HDMITX_DRV_IMP_D2 |
>  			  RG_HDMITX_DRV_IMP_D1 | RG_HDMITX_DRV_IMP_D0);
>  	mtk_hdmi_phy_mask(hdmi_phy, HDMI_CON5,
> -			  (hdmi_phy->ibias << DRV_IBIAS_CLK_SHIFT) |
> -			  (hdmi_phy->ibias << DRV_IBIAS_D2_SHIFT) |
> -			  (hdmi_phy->ibias << DRV_IBIAS_D1_SHIFT) |
> -			  (hdmi_phy->ibias << DRV_IBIAS_D0_SHIFT),
> -			  RG_HDMITX_DRV_IBIAS_CLK | RG_HDMITX_DRV_IBIAS_D2 |
> -			  RG_HDMITX_DRV_IBIAS_D1 | RG_HDMITX_DRV_IBIAS_D0);
> +			  (hdmi_ibias << DRV_IBIAS_CLK_SHIFT) |
> +			  (hdmi_ibias << DRV_IBIAS_D2_SHIFT) |
> +			  (hdmi_ibias << DRV_IBIAS_D1_SHIFT) |
> +			  (hdmi_ibias << DRV_IBIAS_D0_SHIFT),
> +			  RG_HDMITX_DRV_IBIAS_CLK |
> +			  RG_HDMITX_DRV_IBIAS_D2 |
> +			  RG_HDMITX_DRV_IBIAS_D1 |
> +			  RG_HDMITX_DRV_IBIAS_D0);
>  	return 0;
>  }
>  