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From: Stefan Agner <stefan@agner.ch>
To: Robert Chiras <robert.chiras@nxp.com>
Cc: "Marek Vasut" <marex@denx.de>,
	"Mark Rutland" <mark.rutland@arm.com>,
	"Pengutronix Kernel Team" <kernel@pengutronix.de>,
	devicetree@vger.kernel.org, "David Airlie" <airlied@linux.ie>,
	"Fabio Estevam" <festevam@gmail.com>,
	"Guido Günther" <agx@sigxcpu.org>,
	linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
	"Rob Herring" <robh+dt@kernel.org>,
	"NXP Linux Team" <linux-imx@nxp.com>,
	"Daniel Vetter" <daniel@ffwll.ch>,
	"Shawn Guo" <shawnguo@kernel.org>,
	"Sascha Hauer" <s.hauer@pengutronix.de>,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2 12/15] drm/mxsfb: Improve the axi clock usage
Date: Wed, 14 Aug 2019 13:06:30 +0200
Message-ID: <425a854f41248b083ff0c6c93673d696@agner.ch> (raw)
In-Reply-To: <1565779731-1300-13-git-send-email-robert.chiras@nxp.com>

On 2019-08-14 12:48, Robert Chiras wrote:
> Currently, the enable of the axi clock return status is ignored, causing
> issues when the enable fails then we try to disable it. Therefore, it is
> better to check the return status and disable it only when enable
> succeeded.

Is this actually the case in real world sometimes? Why is it failing?

I guess if we do this in one place, we should do it in all places (e.g.
also in mxsfb_crtc_enable, mxsfb_plane_atomic_update..)

--
Stefan

> Also, remove the helper functions around clk_axi, since we can directly
> use the clk API function for enable/disable the clock. Those functions
> are already checking for NULL clk and returning 0 if that's the case.


> 
> Signed-off-by: Robert Chiras <robert.chiras@nxp.com>
> Acked-by: Leonard Crestez <leonard.crestez@nxp.com>
> ---
>  drivers/gpu/drm/mxsfb/mxsfb_crtc.c |  8 ++++----
>  drivers/gpu/drm/mxsfb/mxsfb_drv.c  | 32 +++++++++++++-------------------
>  drivers/gpu/drm/mxsfb/mxsfb_drv.h  |  3 ---
>  3 files changed, 17 insertions(+), 26 deletions(-)
> 
> diff --git a/drivers/gpu/drm/mxsfb/mxsfb_crtc.c
> b/drivers/gpu/drm/mxsfb/mxsfb_crtc.c
> index a4ba368..e727f5e 100644
> --- a/drivers/gpu/drm/mxsfb/mxsfb_crtc.c
> +++ b/drivers/gpu/drm/mxsfb/mxsfb_crtc.c
> @@ -408,7 +408,7 @@ void mxsfb_crtc_enable(struct mxsfb_drm_private *mxsfb)
>  {
>  	dma_addr_t paddr;
>  
> -	mxsfb_enable_axi_clk(mxsfb);
> +	clk_prepare_enable(mxsfb->clk_axi);
>  	writel(0, mxsfb->base + LCDC_CTRL);
>  	mxsfb_crtc_mode_set_nofb(mxsfb);
>  
> @@ -425,7 +425,7 @@ void mxsfb_crtc_enable(struct mxsfb_drm_private *mxsfb)
>  void mxsfb_crtc_disable(struct mxsfb_drm_private *mxsfb)
>  {
>  	mxsfb_disable_controller(mxsfb);
> -	mxsfb_disable_axi_clk(mxsfb);
> +	clk_disable_unprepare(mxsfb->clk_axi);
>  }
>  
>  void mxsfb_plane_atomic_update(struct mxsfb_drm_private *mxsfb,
> @@ -451,8 +451,8 @@ void mxsfb_plane_atomic_update(struct
> mxsfb_drm_private *mxsfb,
>  
>  	paddr = mxsfb_get_fb_paddr(mxsfb);
>  	if (paddr) {
> -		mxsfb_enable_axi_clk(mxsfb);
> +		clk_prepare_enable(mxsfb->clk_axi);
>  		writel(paddr, mxsfb->base + mxsfb->devdata->next_buf);
> -		mxsfb_disable_axi_clk(mxsfb);
> +		clk_disable_unprepare(mxsfb->clk_axi);
>  	}
>  }
> diff --git a/drivers/gpu/drm/mxsfb/mxsfb_drv.c
> b/drivers/gpu/drm/mxsfb/mxsfb_drv.c
> index 6dae2bd..694b287 100644
> --- a/drivers/gpu/drm/mxsfb/mxsfb_drv.c
> +++ b/drivers/gpu/drm/mxsfb/mxsfb_drv.c
> @@ -97,18 +97,6 @@ drm_pipe_to_mxsfb_drm_private(struct
> drm_simple_display_pipe *pipe)
>  	return container_of(pipe, struct mxsfb_drm_private, pipe);
>  }
>  
> -void mxsfb_enable_axi_clk(struct mxsfb_drm_private *mxsfb)
> -{
> -	if (mxsfb->clk_axi)
> -		clk_prepare_enable(mxsfb->clk_axi);
> -}
> -
> -void mxsfb_disable_axi_clk(struct mxsfb_drm_private *mxsfb)
> -{
> -	if (mxsfb->clk_axi)
> -		clk_disable_unprepare(mxsfb->clk_axi);
> -}
> -
>  /**
>   * mxsfb_atomic_helper_check - validate state object
>   * @dev: DRM device
> @@ -229,25 +217,31 @@ static void mxsfb_pipe_update(struct
> drm_simple_display_pipe *pipe,
>  static int mxsfb_pipe_enable_vblank(struct drm_simple_display_pipe *pipe)
>  {
>  	struct mxsfb_drm_private *mxsfb = drm_pipe_to_mxsfb_drm_private(pipe);
> +	int ret = 0;
> +
> +	ret = clk_prepare_enable(mxsfb->clk_axi);
> +	if (ret)
> +		return ret;
>  
>  	/* Clear and enable VBLANK IRQ */
> -	mxsfb_enable_axi_clk(mxsfb);
>  	writel(CTRL1_CUR_FRAME_DONE_IRQ, mxsfb->base + LCDC_CTRL1 + REG_CLR);
>  	writel(CTRL1_CUR_FRAME_DONE_IRQ_EN, mxsfb->base + LCDC_CTRL1 + REG_SET);
> -	mxsfb_disable_axi_clk(mxsfb);
> +	clk_disable_unprepare(mxsfb->clk_axi);
>  
> -	return 0;
> +	return ret;
>  }
>  
>  static void mxsfb_pipe_disable_vblank(struct drm_simple_display_pipe *pipe)
>  {
>  	struct mxsfb_drm_private *mxsfb = drm_pipe_to_mxsfb_drm_private(pipe);
>  
> +	if (clk_prepare_enable(mxsfb->clk_axi))
> +		return;
> +
>  	/* Disable and clear VBLANK IRQ */
> -	mxsfb_enable_axi_clk(mxsfb);
>  	writel(CTRL1_CUR_FRAME_DONE_IRQ_EN, mxsfb->base + LCDC_CTRL1 + REG_CLR);
>  	writel(CTRL1_CUR_FRAME_DONE_IRQ, mxsfb->base + LCDC_CTRL1 + REG_CLR);
> -	mxsfb_disable_axi_clk(mxsfb);
> +	clk_disable_unprepare(mxsfb->clk_axi);
>  }
>  
>  static struct drm_simple_display_pipe_funcs mxsfb_funcs = {
> @@ -413,7 +407,7 @@ static irqreturn_t mxsfb_irq_handler(int irq, void *data)
>  	struct mxsfb_drm_private *mxsfb = drm->dev_private;
>  	u32 reg;
>  
> -	mxsfb_enable_axi_clk(mxsfb);
> +	clk_prepare_enable(mxsfb->clk_axi);
>  
>  	reg = readl(mxsfb->base + LCDC_CTRL1);
>  
> @@ -422,7 +416,7 @@ static irqreturn_t mxsfb_irq_handler(int irq, void *data)
>  
>  	writel(CTRL1_CUR_FRAME_DONE_IRQ, mxsfb->base + LCDC_CTRL1 + REG_CLR);
>  
> -	mxsfb_disable_axi_clk(mxsfb);
> +	clk_disable_unprepare(mxsfb->clk_axi);
>  
>  	return IRQ_HANDLED;
>  }
> diff --git a/drivers/gpu/drm/mxsfb/mxsfb_drv.h
> b/drivers/gpu/drm/mxsfb/mxsfb_drv.h
> index 8fb65d3..d6df8fe 100644
> --- a/drivers/gpu/drm/mxsfb/mxsfb_drv.h
> +++ b/drivers/gpu/drm/mxsfb/mxsfb_drv.h
> @@ -37,9 +37,6 @@ struct mxsfb_drm_private {
>  int mxsfb_setup_crtc(struct drm_device *dev);
>  int mxsfb_create_output(struct drm_device *dev);
>  
> -void mxsfb_enable_axi_clk(struct mxsfb_drm_private *mxsfb);
> -void mxsfb_disable_axi_clk(struct mxsfb_drm_private *mxsfb);
> -
>  void mxsfb_crtc_enable(struct mxsfb_drm_private *mxsfb);
>  void mxsfb_crtc_disable(struct mxsfb_drm_private *mxsfb);
>  void mxsfb_plane_atomic_update(struct mxsfb_drm_private *mxsfb,

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  reply index

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-14 10:48 [PATCH v2 00/15] Improvements and fixes for mxsfb DRM driver Robert Chiras
2019-08-14 10:48 ` [PATCH v2 01/15] drm/mxsfb: Update mxsfb to support a bridge Robert Chiras
2019-08-14 10:48 ` [PATCH v2 02/15] drm/mxsfb: Read bus flags from bridge if present Robert Chiras
2019-08-14 10:48 ` [PATCH v2 03/15] drm/mxsfb: Add defines for the rest of registers Robert Chiras
2019-08-14 10:48 ` [PATCH v2 04/15] drm/mxsfb: Reset vital register for a proper initialization Robert Chiras
2019-08-14 11:11   ` Stefan Agner
2019-08-14 11:38     ` [EXT] " Robert Chiras
2019-08-14 10:48 ` [PATCH v2 05/15] drm/mxsfb: Update register definitions using bit manipulation defines Robert Chiras
2019-08-14 10:48 ` [PATCH v2 06/15] drm/mxsfb: Update mxsfb with additional pixel formats Robert Chiras
2019-08-14 11:44   ` Daniel Stone
2019-08-14 14:58     ` [EXT] " Robert Chiras
2019-08-14 10:48 ` [PATCH v2 07/15] drm/mxsfb: Fix the vblank events Robert Chiras
2019-08-14 17:31   ` Daniel Vetter
2019-08-14 10:48 ` [PATCH v2 08/15] drm/mxsfb: Signal mode changed when bpp changed Robert Chiras
2019-08-14 10:48 ` [PATCH v2 09/15] dt-bindings: display: Add max-res property for mxsfb Robert Chiras
2019-08-14 11:03   ` Stefan Agner
2019-08-14 11:14     ` [EXT] " Robert Chiras
2019-08-14 11:25       ` Stefan Agner
2019-08-14 12:03         ` Robert Chiras
2019-08-14 10:48 ` [PATCH v2 10/15] drm/mxsfb: Add max-res property for MXSFB Robert Chiras
2019-08-14 10:48 ` [PATCH v2 11/15] drm/mxsfb: Update mxsfb to support LCD reset Robert Chiras
2019-08-14 10:48 ` [PATCH v2 12/15] drm/mxsfb: Improve the axi clock usage Robert Chiras
2019-08-14 11:06   ` Stefan Agner [this message]
2019-08-14 11:35     ` [EXT] " Robert Chiras
2019-08-14 10:48 ` [PATCH v2 13/15] drm/mxsfb: Clear OUTSTANDING_REQS bits Robert Chiras
2019-08-14 10:48 ` [PATCH v2 14/15] drm/mxsfb: Add support for horizontal stride Robert Chiras
2019-08-14 10:48 ` [PATCH v2 15/15] drm/mxsfb: Add support for live pixel format change Robert Chiras

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