linux-kernel - Re: [PATCH v10 14/21] drm/mediatek: dpi: Add dpintf support

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Date:   Mon, 13 Jun 2022 14:05:45 +0800
From:   Rex-BC Chen <rex-bc.chen@...iatek.com>
To:     Christophe JAILLET <christophe.jaillet@...adoo.fr>,
        <granquet@...libre.com>
CC:     <airlied@...ux.ie>, <chunfeng.yun@...iatek.com>,
        <chunkuang.hu@...nel.org>, <ck.hu@...iatek.com>, <daniel@...ll.ch>,
        <deller@....de>, <devicetree@...r.kernel.org>,
        <dri-devel@...ts.freedesktop.org>, <jitao.shi@...iatek.com>,
        <kishon@...com>, <krzysztof.kozlowski+dt@...aro.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-fbdev@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <linux-mediatek@...ts.infradead.org>,
        <linux-phy@...ts.infradead.org>,
        <maarten.lankhorst@...ux.intel.com>, <matthias.bgg@...il.com>,
        <mripard@...nel.org>, <msp@...libre.com>, <p.zabel@...gutronix.de>,
        <robh+dt@...nel.org>, <tzimmermann@...e.de>, <vkoul@...nel.org>
Subject: Re: [PATCH v10 14/21] drm/mediatek: dpi: Add dpintf support

On Thu, 2022-06-02 at 07:48 +0200, Christophe JAILLET wrote:
> Le 23/05/2022 à 12:47, Guillaume Ranquet a écrit :
> > dpintf is the displayport interface hardware unit. This unit is
> > similar
> > to dpi and can reuse most of the code.
> > 
> > This patch adds support for mt8195-dpintf to this dpi driver. Main
> > differences are:
> >   - Some features/functional components are not available for
> > dpintf
> >     which are now excluded from code execution once is_dpintf is
> > set
> >   - dpintf can and needs to choose between different clockdividers
> > based
> >     on the clockspeed. This is done by choosing a different clock
> > parent.
> >   - There are two additional clocks that need to be managed. These
> > are
> >     only set for dpintf and will be set to NULL if not supplied.
> > The
> >     clk_* calls handle these as normal clocks then.
> >   - Some register contents differ slightly between the two
> > components. To
> >     work around this I added register bits/masks with a DPINTF_
> > prefix
> >     and use them where different.
> > 
> > Based on a separate driver for dpintf created by
> > Jason-JH.Lin <jason-jh.lin-NuS5LvNUpcJWk0Htik3J/w@...lic.gmane.org>
> > .
> > 
> > Signed-off-by: Markus Schneider-Pargmann <
> > msp-rdvid1DuHRBWk0Htik3J/w@...lic.gmane.org>
> > Signed-off-by: Guillaume Ranquet <
> > granquet-rdvid1DuHRBWk0Htik3J/w@...lic.gmane.org>
> > ---
> >   drivers/gpu/drm/mediatek/mtk_dpi.c          | 126
> > +++++++++++++++++---
> >   drivers/gpu/drm/mediatek/mtk_dpi_regs.h     |  35 ++++++
> >   drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c |   8 ++
> >   drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.h |   1 +
> >   drivers/gpu/drm/mediatek/mtk_drm_drv.c      |   5 +-
> >   include/linux/soc/mediatek/mtk-mmsys.h      |   4 +-
> >   6 files changed, 159 insertions(+), 20 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/mediatek/mtk_dpi.c
> > b/drivers/gpu/drm/mediatek/mtk_dpi.c
> > index eb969c5c5c2e..763bfb700135 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_dpi.c
> > +++ b/drivers/gpu/drm/mediatek/mtk_dpi.c
> > @@ -71,6 +71,7 @@ struct mtk_dpi {
> >   	void __iomem *regs;
> >   	struct device *dev;
> >   	struct clk *engine_clk;
> > +	struct clk *dpi_ck_cg;
> >   	struct clk *pixel_clk;
> >   	struct clk *tvd_clk;
> >   	int irq;
> > @@ -126,6 +127,7 @@ struct mtk_dpi_conf {
> >   	const u32 *output_fmts;
> >   	u32 num_output_fmts;
> >   	bool is_ck_de_pol;
> > +	bool is_dpintf;
> >   	bool swap_input_support;
> >   	/* Mask used for HWIDTH, HPORCH, VSYNC_WIDTH and VSYNC_PORCH
> > (no shift) */
> >   	u32 dimension_mask;
> > @@ -438,6 +440,8 @@ static void mtk_dpi_power_off(struct mtk_dpi
> > *dpi)
> >   	mtk_dpi_disable(dpi);
> >   	clk_disable_unprepare(dpi->pixel_clk);
> >   	clk_disable_unprepare(dpi->engine_clk);
> > +	clk_disable_unprepare(dpi->dpi_ck_cg);
> > +	clk_disable_unprepare(dpi->tvd_clk);
> >   }
> >   
> >   static int mtk_dpi_power_on(struct mtk_dpi *dpi)
> > @@ -447,12 +451,24 @@ static int mtk_dpi_power_on(struct mtk_dpi
> > *dpi)
> >   	if (++dpi->refcount != 1)
> >   		return 0;
> >   
> 
> Hi,
> 
> belwo the error handling path looks odd. (both where we goto, and
> the 
> order of the clk_disable_unprepare() in the error handling path.
> 
> just my 2c,
> 
> CJ
> 

Hello Christophe,

Thanks for your review.
I will fix this order in enxt version.

Thanks

BRs,
Bo-Chen

> > +	ret = clk_prepare_enable(dpi->tvd_clk);
> > +	if (ret) {
> > +		dev_err(dpi->dev, "Failed to enable tvd pll: %d\n",
> > ret);
> > +		goto err_pixel;
> > +	}
> > +
> >   	ret = clk_prepare_enable(dpi->engine_clk);
> >   	if (ret) {
> >   		dev_err(dpi->dev, "Failed to enable engine clock:
> > %d\n", ret);
> >   		goto err_refcount;
> >   	}
> >   
> > +	ret = clk_prepare_enable(dpi->dpi_ck_cg);
> > +	if (ret) {
> > +		dev_err(dpi->dev, "Failed to enable dpi_ck_cg clock:
> > %d\n", ret);
> > +		goto err_ck_cg;
> > +	}
> > +
> >   	ret = clk_prepare_enable(dpi->pixel_clk);
> >   	if (ret) {
> >   		dev_err(dpi->dev, "Failed to enable pixel clock: %d\n",
> > ret);
> > @@ -466,6 +482,8 @@ static int mtk_dpi_power_on(struct mtk_dpi
> > *dpi)
> >   	return 0;
> >   
> >   err_pixel:
> > +	clk_disable_unprepare(dpi->dpi_ck_cg);
> > +err_ck_cg:
> >   	clk_disable_unprepare(dpi->engine_clk);
> >   err_refcount:
> >   	dpi->refcount--;
> 
> [...]
> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@...ts.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

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