media: renesas: fdp1: Identify R-Car Gen2 versions

On R-Car M2-W:

    rcar_fdp1 fe940000.fdp1: FDP1 Unidentifiable (0x02010101)
    rcar_fdp1 fe944000.fdp1: FDP1 Unidentifiable (0x02010101)

Although the IP Internal Data Register on R-Car Gen2 is documented to
contain all zeros, the actual register contents seem to match the FDP1
version ID of R-Car H3 ES1.*, which has just been removed.
Fortunately this version is not used for any other purposes yet.

Fix this by re-adding the ID, now using an R-Car Gen2-specific name.

Fixes: af4273b43f2bd9ee ("media: renesas: fdp1: remove R-Car H3 ES1.* handling")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
Version register contents verified on R-Car H2 ES1.0, R-Car M2-W ES1.0 &
ES3.0, and R-Car E2 ES1.0.  I couldn't get hold of an R-Car M2-N.
---
 drivers/media/platform/renesas/rcar_fdp1.c | 4 ++++
 1 file changed, 4 insertions(+)

On Tue, Apr 25, 2023 at 05:15:02PM +0200, Geert Uytterhoeven wrote:
> On R-Car M2-W:
> 
>     rcar_fdp1 fe940000.fdp1: FDP1 Unidentifiable (0x02010101)
>     rcar_fdp1 fe944000.fdp1: FDP1 Unidentifiable (0x02010101)
> 
> Although the IP Internal Data Register on R-Car Gen2 is documented to
> contain all zeros, the actual register contents seem to match the FDP1
> version ID of R-Car H3 ES1.*, which has just been removed.
> Fortunately this version is not used for any other purposes yet.
> 
> Fix this by re-adding the ID, now using an R-Car Gen2-specific name.
> 
> Fixes: af4273b43f2bd9ee ("media: renesas: fdp1: remove R-Car H3 ES1.* handling")
> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>

>  /* Internal Data (HW Version) */
>  #define FD1_IP_INTDATA			0x0800
> +#define FD1_IP_GEN2			0x02010101

Maybe add a comment here saying that this is needed despite the
information in the datasheets?

Hi Geert,

Thank you for the patch.

On Tue, Apr 25, 2023 at 05:15:02PM +0200, Geert Uytterhoeven wrote:
> On R-Car M2-W:
> 
>     rcar_fdp1 fe940000.fdp1: FDP1 Unidentifiable (0x02010101)
>     rcar_fdp1 fe944000.fdp1: FDP1 Unidentifiable (0x02010101)
> 
> Although the IP Internal Data Register on R-Car Gen2 is documented to
> contain all zeros, the actual register contents seem to match the FDP1
> version ID of R-Car H3 ES1.*, which has just been removed.
> Fortunately this version is not used for any other purposes yet.
> 
> Fix this by re-adding the ID, now using an R-Car Gen2-specific name.
> 
> Fixes: af4273b43f2bd9ee ("media: renesas: fdp1: remove R-Car H3 ES1.* handling")
> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
> ---
> Version register contents verified on R-Car H2 ES1.0, R-Car M2-W ES1.0 &
> ES3.0, and R-Car E2 ES1.0.  I couldn't get hold of an R-Car M2-N.
> ---
>  drivers/media/platform/renesas/rcar_fdp1.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/media/platform/renesas/rcar_fdp1.c b/drivers/media/platform/renesas/rcar_fdp1.c
> index 99af68fddc9249f5..b0a694f9245cc2c6 100644
> --- a/drivers/media/platform/renesas/rcar_fdp1.c
> +++ b/drivers/media/platform/renesas/rcar_fdp1.c
> @@ -254,6 +254,7 @@ MODULE_PARM_DESC(debug, "activate debug info");
>  
>  /* Internal Data (HW Version) */
>  #define FD1_IP_INTDATA			0x0800
> +#define FD1_IP_GEN2			0x02010101

A comment as requested by Wolfram would be nice. I'd mention here that
the same ID is used by H3 ES1.x. With that,

Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>

>  #define FD1_IP_M3W			0x02010202
>  #define FD1_IP_H3			0x02010203
>  #define FD1_IP_M3N			0x02010204
> @@ -2360,6 +2361,9 @@ static int fdp1_probe(struct platform_device *pdev)
>  
>  	hw_version = fdp1_read(fdp1, FD1_IP_INTDATA);
>  	switch (hw_version) {
> +	case FD1_IP_GEN2:
> +		dprintk(fdp1, "FDP1 Version R-Car Gen2\n");
> +		break;
>  	case FD1_IP_M3W:
>  		dprintk(fdp1, "FDP1 Version R-Car M3-W\n");
>  		break;