Re: [PATCH v2] v4l: rcar-fcp: Read IP version register at probe time

From: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
To: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>,
	linux-media@vger.kernel.org
Cc: linux-renesas-soc@vger.kernel.org
Subject: Re: [PATCH v2] v4l: rcar-fcp: Read IP version register at probe time
Date: Fri, 16 Aug 2019 09:07:14 +0100	[thread overview]
Message-ID: <c203bb23-c8f3-ce10-fc15-454083e39ebc@ideasonboard.com> (raw)
In-Reply-To: <20190814145417.30670-1-laurent.pinchart+renesas@ideasonboard.com>

Hi Laurent,

On 14/08/2019 15:54, Laurent Pinchart wrote:
> This helps identifying the IP core version, for debugging purpose only
> for now.
> 
> Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
> ---
> Changes since v1:
> 
> - Use devm_platform_ioremap_resource()
> ---
>  drivers/media/platform/rcar-fcp.c | 41 +++++++++++++++++++++++++++++++
>  1 file changed, 41 insertions(+)
> 
> diff --git a/drivers/media/platform/rcar-fcp.c b/drivers/media/platform/rcar-fcp.c
> index 43c78620c9d8..6e0c0e7c0f8c 100644
> --- a/drivers/media/platform/rcar-fcp.c
> +++ b/drivers/media/platform/rcar-fcp.c
> @@ -8,6 +8,7 @@
>   */
>  
>  #include <linux/device.h>
> +#include <linux/io.h>
>  #include <linux/list.h>
>  #include <linux/module.h>
>  #include <linux/mod_devicetable.h>
> @@ -21,11 +22,38 @@
>  struct rcar_fcp_device {
>  	struct list_head list;
>  	struct device *dev;
> +	void __iomem *iomem;
>  };
>  
>  static LIST_HEAD(fcp_devices);
>  static DEFINE_MUTEX(fcp_lock);
>  
> +#define FCP_VCR			0x0000
> +#define FCP_VCR_CATEGORY_MASK	(0xff << 8)
> +#define FCP_VCR_CATEGORY_SHIFT	8
> +#define FCP_VCR_REVISION_MASK	(0xff << 0)
> +#define FCP_VCR_REVISION_SHIFT	0
> +
> +#define FCP_CFG0		0x0004
> +#define FCP_RST			0x0010
> +#define FCP_STA			0x0018
> +#define FCP_TL_CTRL		0x0070
> +#define FCP_PICINFO1		0x00c4
> +#define FCP_BA_ANC_Y0		0x0100
> +#define FCP_BA_ANC_Y1		0x0104
> +#define FCP_BA_ANC_Y2		0x0108
> +#define FCP_BA_ANC_C		0x010c
> +#define FCP_BA_REF_Y0		0x0110
> +#define FCP_BA_REF_Y1		0x0114
> +#define FCP_BA_REF_Y2		0x0118
> +#define FCP_BA_REF_C		0x011c

Do we need to pull in all these extra register definitions just to read
the version?

They don't hurt if they're for something else later...

Otherwise,

Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>

> +
> +
> +static inline u32 rcar_fcp_read(struct rcar_fcp_device *fcp, u32 reg)
> +{
> +	return ioread32(fcp->iomem + reg);
> +}
> +
>  /* -----------------------------------------------------------------------------
>   * Public API
>   */
> @@ -129,6 +157,7 @@ EXPORT_SYMBOL_GPL(rcar_fcp_disable);
>  static int rcar_fcp_probe(struct platform_device *pdev)
>  {
>  	struct rcar_fcp_device *fcp;
> +	u32 version;
>  
>  	fcp = devm_kzalloc(&pdev->dev, sizeof(*fcp), GFP_KERNEL);
>  	if (fcp == NULL)
> @@ -138,6 +167,18 @@ static int rcar_fcp_probe(struct platform_device *pdev)
>  
>  	pm_runtime_enable(&pdev->dev);
>  
> +	fcp->iomem = devm_platform_ioremap_resource(pdev, 0);
> +	if (IS_ERR(fcp->iomem))
> +		return PTR_ERR(fcp->iomem);
> +
> +	pm_runtime_get_sync(&pdev->dev);
> +	version = rcar_fcp_read(fcp, FCP_VCR);
> +	pm_runtime_put(&pdev->dev);
> +
> +	dev_dbg(&pdev->dev, "FCP category %u revision %u\n",
> +		(version & FCP_VCR_CATEGORY_MASK) >> FCP_VCR_CATEGORY_SHIFT,
> +		(version & FCP_VCR_REVISION_MASK) >> FCP_VCR_REVISION_SHIFT);
> +
>  	mutex_lock(&fcp_lock);
>  	list_add_tail(&fcp->list, &fcp_devices);
>  	mutex_unlock(&fcp_lock);
> 