linux-kernel - Re: [PATCH v4 04/11] media: cadence: csi2rx: Set the STOP bit when stopping a stream

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Message-ID: <YV40Zh9snnXqDIhn@pendragon.ideasonboard.com>
Date:   Thu, 7 Oct 2021 02:42:30 +0300
From:   Laurent Pinchart <laurent.pinchart@...asonboard.com>
To:     Pratyush Yadav <p.yadav@...com>
Cc:     Mauro Carvalho Chehab <mchehab@...nel.org>,
        Nikhil Devshatwar <nikhil.nd@...com>,
        Tomi Valkeinen <tomi.valkeinen@...asonboard.com>,
        Vignesh Raghavendra <vigneshr@...com>,
        Benoit Parrot <bparrot@...com>,
        Maxime Ripard <mripard@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Sakari Ailus <sakari.ailus@...ux.intel.com>,
        Niklas Söderlund 
        <niklas.soderlund+renesas@...natech.se>,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-media@...r.kernel.org
Subject: Re: [PATCH v4 04/11] media: cadence: csi2rx: Set the STOP bit when
 stopping a stream

Hi Pratyush,

Thank you for the patch.

On Wed, Sep 15, 2021 at 05:32:33PM +0530, Pratyush Yadav wrote:
> The stream stop procedure says that the STOP bit should be set when the
> stream is to be stopped, and then the ready bit in stream status
> register polled to make sure the STOP operation is finished.
> 
> Signed-off-by: Pratyush Yadav <p.yadav@...com>
> ---
> 
> (no changes since v1)
> 
>  drivers/media/platform/cadence/cdns-csi2rx.c | 18 +++++++++++++++++-
>  1 file changed, 17 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/media/platform/cadence/cdns-csi2rx.c b/drivers/media/platform/cadence/cdns-csi2rx.c
> index e05d76394cd6..3730e8beee48 100644
> --- a/drivers/media/platform/cadence/cdns-csi2rx.c
> +++ b/drivers/media/platform/cadence/cdns-csi2rx.c
> @@ -8,6 +8,7 @@
>  #include <linux/clk.h>
>  #include <linux/delay.h>
>  #include <linux/io.h>
> +#include <linux/iopoll.h>
>  #include <linux/module.h>
>  #include <linux/of.h>
>  #include <linux/of_graph.h>
> @@ -40,8 +41,12 @@
>  
>  #define CSI2RX_STREAM_CTRL_REG(n)		(CSI2RX_STREAM_BASE(n) + 0x000)
>  #define CSI2RX_STREAM_CTRL_SOFT_RST			BIT(4)
> +#define CSI2RX_STREAM_CTRL_STOP				BIT(1)
>  #define CSI2RX_STREAM_CTRL_START			BIT(0)
>  
> +#define CSI2RX_STREAM_STATUS_REG(n)		(CSI2RX_STREAM_BASE(n) + 0x004)
> +#define CSI2RX_STREAM_STATUS_RDY			BIT(31)
> +
>  #define CSI2RX_STREAM_DATA_CFG_REG(n)		(CSI2RX_STREAM_BASE(n) + 0x008)
>  #define CSI2RX_STREAM_DATA_CFG_EN_VC_SELECT		BIT(31)
>  #define CSI2RX_STREAM_DATA_CFG_VC_SELECT(n)		BIT((n) + 16)
> @@ -321,12 +326,23 @@ static int csi2rx_start(struct csi2rx_priv *csi2rx)
>  static void csi2rx_stop(struct csi2rx_priv *csi2rx)
>  {
>  	unsigned int i;
> +	u32 val;
> +	int ret;
>  
>  	clk_prepare_enable(csi2rx->p_clk);
>  	clk_disable_unprepare(csi2rx->sys_clk);
>  
>  	for (i = 0; i < csi2rx->max_streams; i++) {
> -		writel(0, csi2rx->base + CSI2RX_STREAM_CTRL_REG(i));
> +		writel(CSI2RX_STREAM_CTRL_STOP,
> +		       csi2rx->base + CSI2RX_STREAM_CTRL_REG(i));
> +
> +		ret = readl_relaxed_poll_timeout(csi2rx->base +
> +						 CSI2RX_STREAM_STATUS_REG(i),
> +						 val,
> +						 (val & CSI2RX_STREAM_STATUS_RDY),
> +						 10, 10000);
> +		if (ret)
> +			dev_warn(csi2rx->dev, "Failed to stop stream%d\n", i);

%u for unsigned int.

Reviewed-by: Laurent Pinchart <laurent.pinchart@...asonboard.com>

>  
>  		clk_disable_unprepare(csi2rx->pixel_clk[i]);
>  	}

-- 
Regards,

Laurent Pinchart