media: rcar-csi2: Fix PHTW table values for E3/V3M

Message ID	1544453635-16359-1-git-send-email-jacopo+renesas@jmondi.org (mailing list archive)
State	New
Delegated to:	Kieran Bingham
Headers	show Return-Path: <linux-renesas-soc-owner@kernel.org> sender: jacopo@jmondi.org) by relay3-d.mail.gandi.net (Postfix) with ESMTPSA id 29E2360014; Mon, 10 Dec 2018 14:54:08 +0000 (UTC) From: Jacopo Mondi <jacopo+renesas@jmondi.org> To: niklas.soderlund@ragnatech.se, laurent.pinchart@ideasonboard.com, kieran.bingham@ideasonboard.com Cc: Jacopo Mondi <jacopo+renesas@jmondi.org>, linux-media@vger.kernel.org, linux-renesas-soc@vger.kernel.org Subject: [PATCH] media: rcar-csi2: Fix PHTW table values for E3/V3M Date: Mon, 10 Dec 2018 15:53:55 +0100 Message-Id: <1544453635-16359-1-git-send-email-jacopo+renesas@jmondi.org> Sender: linux-renesas-soc-owner@vger.kernel.org Precedence: bulk
Series	media: rcar-csi2: Fix PHTW table values for E3/V3M \| expand media: rcar-csi2: Fix PHTW table values for E3/V3M

Jacopo Mondi Dec. 10, 2018, 2:53 p.m. UTC

The PHTW selection algorithm implemented in rcsi2_phtw_write_mbps() checks for
lower bound of the interval used to match the desired bandwidth. Use that
in place of the currently used upport bound.

Fixes: 10c08812fe60 ("media: rcar: rcar-csi2: Update V3M/E3 PHTW tables")
Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
---
 drivers/media/platform/rcar-vin/rcar-csi2.c | 62 ++++++++++++++---------------
 1 file changed, 31 insertions(+), 31 deletions(-)

--
2.7.4

Niklas Söderlund Dec. 10, 2018, 3:24 p.m. UTC | #1

Hi Jacopo,

Thanks for fixing this.

On 2018-12-10 15:53:55 +0100, Jacopo Mondi wrote:
> The PHTW selection algorithm implemented in rcsi2_phtw_write_mbps() checks for
> lower bound of the interval used to match the desired bandwidth. Use that
> in place of the currently used upport bound.
> 
> Fixes: 10c08812fe60 ("media: rcar: rcar-csi2: Update V3M/E3 PHTW tables")
> Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>

Acked-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>

> ---
>  drivers/media/platform/rcar-vin/rcar-csi2.c | 62 ++++++++++++++---------------
>  1 file changed, 31 insertions(+), 31 deletions(-)
> 
> diff --git a/drivers/media/platform/rcar-vin/rcar-csi2.c b/drivers/media/platform/rcar-vin/rcar-csi2.c
> index 80ad906d1136..7e9cb8bcfe70 100644
> --- a/drivers/media/platform/rcar-vin/rcar-csi2.c
> +++ b/drivers/media/platform/rcar-vin/rcar-csi2.c
> @@ -152,37 +152,37 @@ static const struct rcsi2_mbps_reg phtw_mbps_h3_v3h_m3n[] = {
>  };
> 
>  static const struct rcsi2_mbps_reg phtw_mbps_v3m_e3[] = {
> -	{ .mbps =   89, .reg = 0x00 },
> -	{ .mbps =   99, .reg = 0x20 },
> -	{ .mbps =  109, .reg = 0x40 },
> -	{ .mbps =  129, .reg = 0x02 },
> -	{ .mbps =  139, .reg = 0x22 },
> -	{ .mbps =  149, .reg = 0x42 },
> -	{ .mbps =  169, .reg = 0x04 },
> -	{ .mbps =  179, .reg = 0x24 },
> -	{ .mbps =  199, .reg = 0x44 },
> -	{ .mbps =  219, .reg = 0x06 },
> -	{ .mbps =  239, .reg = 0x26 },
> -	{ .mbps =  249, .reg = 0x46 },
> -	{ .mbps =  269, .reg = 0x08 },
> -	{ .mbps =  299, .reg = 0x28 },
> -	{ .mbps =  329, .reg = 0x0a },
> -	{ .mbps =  359, .reg = 0x2a },
> -	{ .mbps =  399, .reg = 0x4a },
> -	{ .mbps =  449, .reg = 0x0c },
> -	{ .mbps =  499, .reg = 0x2c },
> -	{ .mbps =  549, .reg = 0x0e },
> -	{ .mbps =  599, .reg = 0x2e },
> -	{ .mbps =  649, .reg = 0x10 },
> -	{ .mbps =  699, .reg = 0x30 },
> -	{ .mbps =  749, .reg = 0x12 },
> -	{ .mbps =  799, .reg = 0x32 },
> -	{ .mbps =  849, .reg = 0x52 },
> -	{ .mbps =  899, .reg = 0x72 },
> -	{ .mbps =  949, .reg = 0x14 },
> -	{ .mbps =  999, .reg = 0x34 },
> -	{ .mbps = 1049, .reg = 0x54 },
> -	{ .mbps = 1099, .reg = 0x74 },
> +	{ .mbps =   80, .reg = 0x00 },
> +	{ .mbps =   90, .reg = 0x20 },
> +	{ .mbps =  100, .reg = 0x40 },
> +	{ .mbps =  110, .reg = 0x02 },
> +	{ .mbps =  130, .reg = 0x22 },
> +	{ .mbps =  140, .reg = 0x42 },
> +	{ .mbps =  150, .reg = 0x04 },
> +	{ .mbps =  170, .reg = 0x24 },
> +	{ .mbps =  180, .reg = 0x44 },
> +	{ .mbps =  200, .reg = 0x06 },
> +	{ .mbps =  220, .reg = 0x26 },
> +	{ .mbps =  240, .reg = 0x46 },
> +	{ .mbps =  250, .reg = 0x08 },
> +	{ .mbps =  270, .reg = 0x28 },
> +	{ .mbps =  300, .reg = 0x0a },
> +	{ .mbps =  330, .reg = 0x2a },
> +	{ .mbps =  360, .reg = 0x4a },
> +	{ .mbps =  400, .reg = 0x0c },
> +	{ .mbps =  450, .reg = 0x2c },
> +	{ .mbps =  500, .reg = 0x0e },
> +	{ .mbps =  550, .reg = 0x2e },
> +	{ .mbps =  600, .reg = 0x10 },
> +	{ .mbps =  650, .reg = 0x30 },
> +	{ .mbps =  700, .reg = 0x12 },
> +	{ .mbps =  750, .reg = 0x32 },
> +	{ .mbps =  800, .reg = 0x52 },
> +	{ .mbps =  850, .reg = 0x72 },
> +	{ .mbps =  900, .reg = 0x14 },
> +	{ .mbps =  950, .reg = 0x34 },
> +	{ .mbps = 1000, .reg = 0x54 },
> +	{ .mbps = 1050, .reg = 0x74 },
>  	{ .mbps = 1125, .reg = 0x16 },
>  	{ /* sentinel */ },
>  };
> --
> 2.7.4
>

Laurent Pinchart Dec. 10, 2018, 8:16 p.m. UTC | #2

Hi Jacopo,

Thank you for the patch.

On Monday, 10 December 2018 16:53:55 EET Jacopo Mondi wrote:
> The PHTW selection algorithm implemented in rcsi2_phtw_write_mbps() checks
> for lower bound of the interval used to match the desired bandwidth. Use
> that in place of the currently used upport bound.

The rcsi2_phtw_write_mbps() function performs the following (error handling 
removed):

        const struct rcsi2_mbps_reg *value;

        for (value = values; value->mbps; value++)
                if (value->mbps >= mbps)
                        break;

        return rcsi2_phtw_write(priv, value->reg, code);

With this patch, an mbps value of 85 will match the second entry in the 
phtw_mbps_v3m_e3 table:

[0]	{ .mbps =   80, .reg = 0x00 },
[1]	{ .mbps =   90, .reg = 0x20 },
...

The datasheet however documents the range 80-89 to map to 0x00.

What am I missing ?

> Fixes: 10c08812fe60 ("media: rcar: rcar-csi2: Update V3M/E3 PHTW tables")
> Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
> ---
>  drivers/media/platform/rcar-vin/rcar-csi2.c | 62 ++++++++++++-------------
>  1 file changed, 31 insertions(+), 31 deletions(-)
> 
> diff --git a/drivers/media/platform/rcar-vin/rcar-csi2.c
> b/drivers/media/platform/rcar-vin/rcar-csi2.c index
> 80ad906d1136..7e9cb8bcfe70 100644
> --- a/drivers/media/platform/rcar-vin/rcar-csi2.c
> +++ b/drivers/media/platform/rcar-vin/rcar-csi2.c
> @@ -152,37 +152,37 @@ static const struct rcsi2_mbps_reg
> phtw_mbps_h3_v3h_m3n[] = { };
> 
>  static const struct rcsi2_mbps_reg phtw_mbps_v3m_e3[] = {
> -	{ .mbps =   89, .reg = 0x00 },
> -	{ .mbps =   99, .reg = 0x20 },
> -	{ .mbps =  109, .reg = 0x40 },
> -	{ .mbps =  129, .reg = 0x02 },
> -	{ .mbps =  139, .reg = 0x22 },
> -	{ .mbps =  149, .reg = 0x42 },
> -	{ .mbps =  169, .reg = 0x04 },
> -	{ .mbps =  179, .reg = 0x24 },
> -	{ .mbps =  199, .reg = 0x44 },
> -	{ .mbps =  219, .reg = 0x06 },
> -	{ .mbps =  239, .reg = 0x26 },
> -	{ .mbps =  249, .reg = 0x46 },
> -	{ .mbps =  269, .reg = 0x08 },
> -	{ .mbps =  299, .reg = 0x28 },
> -	{ .mbps =  329, .reg = 0x0a },
> -	{ .mbps =  359, .reg = 0x2a },
> -	{ .mbps =  399, .reg = 0x4a },
> -	{ .mbps =  449, .reg = 0x0c },
> -	{ .mbps =  499, .reg = 0x2c },
> -	{ .mbps =  549, .reg = 0x0e },
> -	{ .mbps =  599, .reg = 0x2e },
> -	{ .mbps =  649, .reg = 0x10 },
> -	{ .mbps =  699, .reg = 0x30 },
> -	{ .mbps =  749, .reg = 0x12 },
> -	{ .mbps =  799, .reg = 0x32 },
> -	{ .mbps =  849, .reg = 0x52 },
> -	{ .mbps =  899, .reg = 0x72 },
> -	{ .mbps =  949, .reg = 0x14 },
> -	{ .mbps =  999, .reg = 0x34 },
> -	{ .mbps = 1049, .reg = 0x54 },
> -	{ .mbps = 1099, .reg = 0x74 },
> +	{ .mbps =   80, .reg = 0x00 },
> +	{ .mbps =   90, .reg = 0x20 },
> +	{ .mbps =  100, .reg = 0x40 },
> +	{ .mbps =  110, .reg = 0x02 },
> +	{ .mbps =  130, .reg = 0x22 },
> +	{ .mbps =  140, .reg = 0x42 },
> +	{ .mbps =  150, .reg = 0x04 },
> +	{ .mbps =  170, .reg = 0x24 },
> +	{ .mbps =  180, .reg = 0x44 },
> +	{ .mbps =  200, .reg = 0x06 },
> +	{ .mbps =  220, .reg = 0x26 },
> +	{ .mbps =  240, .reg = 0x46 },
> +	{ .mbps =  250, .reg = 0x08 },
> +	{ .mbps =  270, .reg = 0x28 },
> +	{ .mbps =  300, .reg = 0x0a },
> +	{ .mbps =  330, .reg = 0x2a },
> +	{ .mbps =  360, .reg = 0x4a },
> +	{ .mbps =  400, .reg = 0x0c },
> +	{ .mbps =  450, .reg = 0x2c },
> +	{ .mbps =  500, .reg = 0x0e },
> +	{ .mbps =  550, .reg = 0x2e },
> +	{ .mbps =  600, .reg = 0x10 },
> +	{ .mbps =  650, .reg = 0x30 },
> +	{ .mbps =  700, .reg = 0x12 },
> +	{ .mbps =  750, .reg = 0x32 },
> +	{ .mbps =  800, .reg = 0x52 },
> +	{ .mbps =  850, .reg = 0x72 },
> +	{ .mbps =  900, .reg = 0x14 },
> +	{ .mbps =  950, .reg = 0x34 },
> +	{ .mbps = 1000, .reg = 0x54 },
> +	{ .mbps = 1050, .reg = 0x74 },
>  	{ .mbps = 1125, .reg = 0x16 },
>  	{ /* sentinel */ },
>  };

Niklas Söderlund Dec. 11, 2018, 2:01 a.m. UTC | #3

Hi Laurent,

Thanks for your feedback,

On 2018-12-10 22:16:52 +0200, Laurent Pinchart wrote:
> Hi Jacopo,
> 
> Thank you for the patch.
> 
> On Monday, 10 December 2018 16:53:55 EET Jacopo Mondi wrote:
> > The PHTW selection algorithm implemented in rcsi2_phtw_write_mbps() checks
> > for lower bound of the interval used to match the desired bandwidth. Use
> > that in place of the currently used upport bound.
> 
> The rcsi2_phtw_write_mbps() function performs the following (error handling 
> removed):
> 
>         const struct rcsi2_mbps_reg *value;
> 
>         for (value = values; value->mbps; value++)
>                 if (value->mbps >= mbps)
>                         break;
> 
>         return rcsi2_phtw_write(priv, value->reg, code);
> 
> With this patch, an mbps value of 85 will match the second entry in the 
> phtw_mbps_v3m_e3 table:
> 
> [0]	{ .mbps =   80, .reg = 0x00 },
> [1]	{ .mbps =   90, .reg = 0x20 },
> ...
> 
> The datasheet however documents the range 80-89 to map to 0x00.
> 
> What am I missing ?

I'm afraid you are missing a issue with the original implementation of 
the rcar-csi2 driver (my fault). The issue you point out is a problem 
with the current freq selection logic not the tables themself which 
needs to be corrected.

This patch aligns the table with the other tables in the driver and is 
sound. A patch (Jacopo care to submit it?) is needed to resolve the 
faulty logic in the driver. It should select the range according to 
Laurents findings and not the range above it as the current code does.

> 
> > Fixes: 10c08812fe60 ("media: rcar: rcar-csi2: Update V3M/E3 PHTW tables")
> > Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
> > ---
> >  drivers/media/platform/rcar-vin/rcar-csi2.c | 62 ++++++++++++-------------
> >  1 file changed, 31 insertions(+), 31 deletions(-)
> > 
> > diff --git a/drivers/media/platform/rcar-vin/rcar-csi2.c
> > b/drivers/media/platform/rcar-vin/rcar-csi2.c index
> > 80ad906d1136..7e9cb8bcfe70 100644
> > --- a/drivers/media/platform/rcar-vin/rcar-csi2.c
> > +++ b/drivers/media/platform/rcar-vin/rcar-csi2.c
> > @@ -152,37 +152,37 @@ static const struct rcsi2_mbps_reg
> > phtw_mbps_h3_v3h_m3n[] = { };
> > 
> >  static const struct rcsi2_mbps_reg phtw_mbps_v3m_e3[] = {
> > -	{ .mbps =   89, .reg = 0x00 },
> > -	{ .mbps =   99, .reg = 0x20 },
> > -	{ .mbps =  109, .reg = 0x40 },
> > -	{ .mbps =  129, .reg = 0x02 },
> > -	{ .mbps =  139, .reg = 0x22 },
> > -	{ .mbps =  149, .reg = 0x42 },
> > -	{ .mbps =  169, .reg = 0x04 },
> > -	{ .mbps =  179, .reg = 0x24 },
> > -	{ .mbps =  199, .reg = 0x44 },
> > -	{ .mbps =  219, .reg = 0x06 },
> > -	{ .mbps =  239, .reg = 0x26 },
> > -	{ .mbps =  249, .reg = 0x46 },
> > -	{ .mbps =  269, .reg = 0x08 },
> > -	{ .mbps =  299, .reg = 0x28 },
> > -	{ .mbps =  329, .reg = 0x0a },
> > -	{ .mbps =  359, .reg = 0x2a },
> > -	{ .mbps =  399, .reg = 0x4a },
> > -	{ .mbps =  449, .reg = 0x0c },
> > -	{ .mbps =  499, .reg = 0x2c },
> > -	{ .mbps =  549, .reg = 0x0e },
> > -	{ .mbps =  599, .reg = 0x2e },
> > -	{ .mbps =  649, .reg = 0x10 },
> > -	{ .mbps =  699, .reg = 0x30 },
> > -	{ .mbps =  749, .reg = 0x12 },
> > -	{ .mbps =  799, .reg = 0x32 },
> > -	{ .mbps =  849, .reg = 0x52 },
> > -	{ .mbps =  899, .reg = 0x72 },
> > -	{ .mbps =  949, .reg = 0x14 },
> > -	{ .mbps =  999, .reg = 0x34 },
> > -	{ .mbps = 1049, .reg = 0x54 },
> > -	{ .mbps = 1099, .reg = 0x74 },
> > +	{ .mbps =   80, .reg = 0x00 },
> > +	{ .mbps =   90, .reg = 0x20 },
> > +	{ .mbps =  100, .reg = 0x40 },
> > +	{ .mbps =  110, .reg = 0x02 },
> > +	{ .mbps =  130, .reg = 0x22 },
> > +	{ .mbps =  140, .reg = 0x42 },
> > +	{ .mbps =  150, .reg = 0x04 },
> > +	{ .mbps =  170, .reg = 0x24 },
> > +	{ .mbps =  180, .reg = 0x44 },
> > +	{ .mbps =  200, .reg = 0x06 },
> > +	{ .mbps =  220, .reg = 0x26 },
> > +	{ .mbps =  240, .reg = 0x46 },
> > +	{ .mbps =  250, .reg = 0x08 },
> > +	{ .mbps =  270, .reg = 0x28 },
> > +	{ .mbps =  300, .reg = 0x0a },
> > +	{ .mbps =  330, .reg = 0x2a },
> > +	{ .mbps =  360, .reg = 0x4a },
> > +	{ .mbps =  400, .reg = 0x0c },
> > +	{ .mbps =  450, .reg = 0x2c },
> > +	{ .mbps =  500, .reg = 0x0e },
> > +	{ .mbps =  550, .reg = 0x2e },
> > +	{ .mbps =  600, .reg = 0x10 },
> > +	{ .mbps =  650, .reg = 0x30 },
> > +	{ .mbps =  700, .reg = 0x12 },
> > +	{ .mbps =  750, .reg = 0x32 },
> > +	{ .mbps =  800, .reg = 0x52 },
> > +	{ .mbps =  850, .reg = 0x72 },
> > +	{ .mbps =  900, .reg = 0x14 },
> > +	{ .mbps =  950, .reg = 0x34 },
> > +	{ .mbps = 1000, .reg = 0x54 },
> > +	{ .mbps = 1050, .reg = 0x74 },
> >  	{ .mbps = 1125, .reg = 0x16 },
> >  	{ /* sentinel */ },
> >  };
> 
> -- 
> Regards,
> 
> Laurent Pinchart
> 
> 
>

Laurent Pinchart Dec. 11, 2018, 7:49 a.m. UTC | #4

Hi Niklas,

On Tuesday, 11 December 2018 04:01:15 EET Niklas Söderlund wrote:
> On 2018-12-10 22:16:52 +0200, Laurent Pinchart wrote:
> > On Monday, 10 December 2018 16:53:55 EET Jacopo Mondi wrote:
> >> The PHTW selection algorithm implemented in rcsi2_phtw_write_mbps()
> >> checks for lower bound of the interval used to match the desired
> >> bandwidth. Use that in place of the currently used upport bound.
> > 
> > The rcsi2_phtw_write_mbps() function performs the following (error
> > handling removed):
> > 
> >         const struct rcsi2_mbps_reg *value;
> >         
> >         for (value = values; value->mbps; value++)
> >                 if (value->mbps >= mbps)
> >                         break;
> >         
> >         return rcsi2_phtw_write(priv, value->reg, code);
> > 
> > With this patch, an mbps value of 85 will match the second entry in the
> > phtw_mbps_v3m_e3 table:
> > 
> > [0]	{ .mbps =   80, .reg = 0x00 },
> > [1]	{ .mbps =   90, .reg = 0x20 },
> > ...
> > 
> > The datasheet however documents the range 80-89 to map to 0x00.
> > 
> > What am I missing ?
> 
> I'm afraid you are missing a issue with the original implementation of
> the rcar-csi2 driver (my fault). The issue you point out is a problem
> with the current freq selection logic not the tables themself which
> needs to be corrected.
> 
> This patch aligns the table with the other tables in the driver and is
> sound. A patch (Jacopo care to submit it?) is needed to resolve the
> faulty logic in the driver. It should select the range according to
> Laurents findings and not the range above it as the current code does.

I wonder whether we should instead modify the tables, to avoid making the 
selection logic more complicated and less efficient CPU-wise.

Speaking of which, the tables are interestingly specified in three different 
ways in the datasheet:

- The TESTDIN_DATA table specifies non-overlapping ranges

e.g. [80, 89]: 0x00, [90, 99]: 0x20, [100, 109]: 0x40, ...

In this regard this patch is an improvement (that is if the faulty selection 
logic gets fixed), as otherwise a frequency of 109.5 would be classified in 
the [110, 129] range, while I think it is meant to be in the [100, 109] range.

Another option would be to set the table mbps value to the high bound of the 
range:

        { .mbps =   90, .reg = 0x00 },
        { .mbps =  100, .reg = 0x20 },
        { .mbps =  110, .reg = 0x40 },
        ...

and use strict lower comparison logic:

        const struct rcsi2_mbps_reg *value;

        for (value = values; value->mbps; value++)
                if (mbps < value->mbps)
                        break

- The PHTW table specifies individual bit rates

e.g. 80: 0x86, 90: 0x86, 100: 0x87, ..

I'm not sure how to interpret this. If I had to guess, I would say it means

[80, 90[: 0x86, [90, 100[: 0x86, [100, 110[: 0x87, ..

We could thus use the same logic than for the TESTDIN_DATA table (and while at 
it merge adjacent ranges that share the same PHTW value).

- The HSFREQRANGE tables specify overlapping ranges

e.g. [80, 131.25]: 0x20, [80.75, 141.75]: 0x30, [90.25, 152.25]: 0x01, ...

This has to be converted to non-overlapping ranges. I would advice centering 
each non-overlapping range to the center of the corresponding overlapping 
range. Today we instead have non-overlapping ranges in the driver whose bounds 
are set to the center of the overlapping ranges, and I don't think this is 
right.

And we could then use the same logic as above here too.

The downside is that the tables would need to be carefully reviewed as they 
would derive from the values in the datasheet instead of computing them 
blindly, and the upside would be simpler code. If we want to instead copy the 
tables blindly for ease of review, then I think we'll need more complex 
selection logic, with different logics for the different tables.

> >> Fixes: 10c08812fe60 ("media: rcar: rcar-csi2: Update V3M/E3 PHTW
> >> tables")
> >> Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
> >> ---
> >> 
> >>  drivers/media/platform/rcar-vin/rcar-csi2.c | 62 +++++++++++------------
> >>  1 file changed, 31 insertions(+), 31 deletions(-)
> >> 
> >> diff --git a/drivers/media/platform/rcar-vin/rcar-csi2.c
> >> b/drivers/media/platform/rcar-vin/rcar-csi2.c index
> >> 80ad906d1136..7e9cb8bcfe70 100644
> >> --- a/drivers/media/platform/rcar-vin/rcar-csi2.c
> >> +++ b/drivers/media/platform/rcar-vin/rcar-csi2.c
> >> @@ -152,37 +152,37 @@ static const struct rcsi2_mbps_reg
> >> phtw_mbps_h3_v3h_m3n[] = { };
> >> 
> >>  static const struct rcsi2_mbps_reg phtw_mbps_v3m_e3[] = {
> >> -	{ .mbps =   89, .reg = 0x00 },
> >> -	{ .mbps =   99, .reg = 0x20 },
> >> -	{ .mbps =  109, .reg = 0x40 },
> >> -	{ .mbps =  129, .reg = 0x02 },
> >> -	{ .mbps =  139, .reg = 0x22 },
> >> -	{ .mbps =  149, .reg = 0x42 },
> >> -	{ .mbps =  169, .reg = 0x04 },
> >> -	{ .mbps =  179, .reg = 0x24 },
> >> -	{ .mbps =  199, .reg = 0x44 },
> >> -	{ .mbps =  219, .reg = 0x06 },
> >> -	{ .mbps =  239, .reg = 0x26 },
> >> -	{ .mbps =  249, .reg = 0x46 },
> >> -	{ .mbps =  269, .reg = 0x08 },
> >> -	{ .mbps =  299, .reg = 0x28 },
> >> -	{ .mbps =  329, .reg = 0x0a },
> >> -	{ .mbps =  359, .reg = 0x2a },
> >> -	{ .mbps =  399, .reg = 0x4a },
> >> -	{ .mbps =  449, .reg = 0x0c },
> >> -	{ .mbps =  499, .reg = 0x2c },
> >> -	{ .mbps =  549, .reg = 0x0e },
> >> -	{ .mbps =  599, .reg = 0x2e },
> >> -	{ .mbps =  649, .reg = 0x10 },
> >> -	{ .mbps =  699, .reg = 0x30 },
> >> -	{ .mbps =  749, .reg = 0x12 },
> >> -	{ .mbps =  799, .reg = 0x32 },
> >> -	{ .mbps =  849, .reg = 0x52 },
> >> -	{ .mbps =  899, .reg = 0x72 },
> >> -	{ .mbps =  949, .reg = 0x14 },
> >> -	{ .mbps =  999, .reg = 0x34 },
> >> -	{ .mbps = 1049, .reg = 0x54 },
> >> -	{ .mbps = 1099, .reg = 0x74 },
> >> +	{ .mbps =   80, .reg = 0x00 },
> >> +	{ .mbps =   90, .reg = 0x20 },
> >> +	{ .mbps =  100, .reg = 0x40 },
> >> +	{ .mbps =  110, .reg = 0x02 },
> >> +	{ .mbps =  130, .reg = 0x22 },
> >> +	{ .mbps =  140, .reg = 0x42 },
> >> +	{ .mbps =  150, .reg = 0x04 },
> >> +	{ .mbps =  170, .reg = 0x24 },
> >> +	{ .mbps =  180, .reg = 0x44 },
> >> +	{ .mbps =  200, .reg = 0x06 },
> >> +	{ .mbps =  220, .reg = 0x26 },
> >> +	{ .mbps =  240, .reg = 0x46 },
> >> +	{ .mbps =  250, .reg = 0x08 },
> >> +	{ .mbps =  270, .reg = 0x28 },
> >> +	{ .mbps =  300, .reg = 0x0a },
> >> +	{ .mbps =  330, .reg = 0x2a },
> >> +	{ .mbps =  360, .reg = 0x4a },
> >> +	{ .mbps =  400, .reg = 0x0c },
> >> +	{ .mbps =  450, .reg = 0x2c },
> >> +	{ .mbps =  500, .reg = 0x0e },
> >> +	{ .mbps =  550, .reg = 0x2e },
> >> +	{ .mbps =  600, .reg = 0x10 },
> >> +	{ .mbps =  650, .reg = 0x30 },
> >> +	{ .mbps =  700, .reg = 0x12 },
> >> +	{ .mbps =  750, .reg = 0x32 },
> >> +	{ .mbps =  800, .reg = 0x52 },
> >> +	{ .mbps =  850, .reg = 0x72 },
> >> +	{ .mbps =  900, .reg = 0x14 },
> >> +	{ .mbps =  950, .reg = 0x34 },
> >> +	{ .mbps = 1000, .reg = 0x54 },
> >> +	{ .mbps = 1050, .reg = 0x74 },
> >>  	{ .mbps = 1125, .reg = 0x16 },
> >>  	{ /* sentinel */ },
> >>  
> >>  };

Jacopo Mondi Dec. 11, 2018, 11:33 a.m. UTC | #5

Hi Laurent, Niklas,

On Tue, Dec 11, 2018 at 03:01:15AM +0100, Niklas Söderlund wrote:
> Hi Laurent,
>
> Thanks for your feedback,
>
> On 2018-12-10 22:16:52 +0200, Laurent Pinchart wrote:
> > Hi Jacopo,
> >
> > Thank you for the patch.
> >
> > On Monday, 10 December 2018 16:53:55 EET Jacopo Mondi wrote:
> > > The PHTW selection algorithm implemented in rcsi2_phtw_write_mbps() checks
> > > for lower bound of the interval used to match the desired bandwidth. Use
> > > that in place of the currently used upport bound.
> >
> > The rcsi2_phtw_write_mbps() function performs the following (error handling
> > removed):
> >
> >         const struct rcsi2_mbps_reg *value;
> >
> >         for (value = values; value->mbps; value++)
> >                 if (value->mbps >= mbps)
> >                         break;
> >
> >         return rcsi2_phtw_write(priv, value->reg, code);
> >
> > With this patch, an mbps value of 85 will match the second entry in the
> > phtw_mbps_v3m_e3 table:
> >
> > [0]	{ .mbps =   80, .reg = 0x00 },
> > [1]	{ .mbps =   90, .reg = 0x20 },
> > ...
> >
> > The datasheet however documents the range 80-89 to map to 0x00.
> >
> > What am I missing ?
>
> I'm afraid you are missing a issue with the original implementation of
> the rcar-csi2 driver (my fault). The issue you point out is a problem
> with the current freq selection logic not the tables themself which
> needs to be corrected.
>
> This patch aligns the table with the other tables in the driver and is
> sound. A patch (Jacopo care to submit it?) is needed to resolve the
> faulty logic in the driver. It should select the range according to
> Laurents findings and not the range above it as the current code does.
>
> >

I've been notified my previous patch broke the matching logic in the
CSI-2 driver, and so to keep it consistent, I basically reverted what
I've done.

Anyway, a re-work of those matching loop and tables is welcome, and as
you suggested in your last email, it should be done not only for PHTW
but for other tables as well.

In the meantime, I think this patch should go in (afaik there have
been no functional changes on E3/V3M) so that we start from a
(slightly suboptimal) fixed point.

Thanks
   j

> > > Fixes: 10c08812fe60 ("media: rcar: rcar-csi2: Update V3M/E3 PHTW tables")
> > > Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
> > > ---
> > >  drivers/media/platform/rcar-vin/rcar-csi2.c | 62 ++++++++++++-------------
> > >  1 file changed, 31 insertions(+), 31 deletions(-)
> > >
> > > diff --git a/drivers/media/platform/rcar-vin/rcar-csi2.c
> > > b/drivers/media/platform/rcar-vin/rcar-csi2.c index
> > > 80ad906d1136..7e9cb8bcfe70 100644
> > > --- a/drivers/media/platform/rcar-vin/rcar-csi2.c
> > > +++ b/drivers/media/platform/rcar-vin/rcar-csi2.c
> > > @@ -152,37 +152,37 @@ static const struct rcsi2_mbps_reg
> > > phtw_mbps_h3_v3h_m3n[] = { };
> > >
> > >  static const struct rcsi2_mbps_reg phtw_mbps_v3m_e3[] = {
> > > -	{ .mbps =   89, .reg = 0x00 },
> > > -	{ .mbps =   99, .reg = 0x20 },
> > > -	{ .mbps =  109, .reg = 0x40 },
> > > -	{ .mbps =  129, .reg = 0x02 },
> > > -	{ .mbps =  139, .reg = 0x22 },
> > > -	{ .mbps =  149, .reg = 0x42 },
> > > -	{ .mbps =  169, .reg = 0x04 },
> > > -	{ .mbps =  179, .reg = 0x24 },
> > > -	{ .mbps =  199, .reg = 0x44 },
> > > -	{ .mbps =  219, .reg = 0x06 },
> > > -	{ .mbps =  239, .reg = 0x26 },
> > > -	{ .mbps =  249, .reg = 0x46 },
> > > -	{ .mbps =  269, .reg = 0x08 },
> > > -	{ .mbps =  299, .reg = 0x28 },
> > > -	{ .mbps =  329, .reg = 0x0a },
> > > -	{ .mbps =  359, .reg = 0x2a },
> > > -	{ .mbps =  399, .reg = 0x4a },
> > > -	{ .mbps =  449, .reg = 0x0c },
> > > -	{ .mbps =  499, .reg = 0x2c },
> > > -	{ .mbps =  549, .reg = 0x0e },
> > > -	{ .mbps =  599, .reg = 0x2e },
> > > -	{ .mbps =  649, .reg = 0x10 },
> > > -	{ .mbps =  699, .reg = 0x30 },
> > > -	{ .mbps =  749, .reg = 0x12 },
> > > -	{ .mbps =  799, .reg = 0x32 },
> > > -	{ .mbps =  849, .reg = 0x52 },
> > > -	{ .mbps =  899, .reg = 0x72 },
> > > -	{ .mbps =  949, .reg = 0x14 },
> > > -	{ .mbps =  999, .reg = 0x34 },
> > > -	{ .mbps = 1049, .reg = 0x54 },
> > > -	{ .mbps = 1099, .reg = 0x74 },
> > > +	{ .mbps =   80, .reg = 0x00 },
> > > +	{ .mbps =   90, .reg = 0x20 },
> > > +	{ .mbps =  100, .reg = 0x40 },
> > > +	{ .mbps =  110, .reg = 0x02 },
> > > +	{ .mbps =  130, .reg = 0x22 },
> > > +	{ .mbps =  140, .reg = 0x42 },
> > > +	{ .mbps =  150, .reg = 0x04 },
> > > +	{ .mbps =  170, .reg = 0x24 },
> > > +	{ .mbps =  180, .reg = 0x44 },
> > > +	{ .mbps =  200, .reg = 0x06 },
> > > +	{ .mbps =  220, .reg = 0x26 },
> > > +	{ .mbps =  240, .reg = 0x46 },
> > > +	{ .mbps =  250, .reg = 0x08 },
> > > +	{ .mbps =  270, .reg = 0x28 },
> > > +	{ .mbps =  300, .reg = 0x0a },
> > > +	{ .mbps =  330, .reg = 0x2a },
> > > +	{ .mbps =  360, .reg = 0x4a },
> > > +	{ .mbps =  400, .reg = 0x0c },
> > > +	{ .mbps =  450, .reg = 0x2c },
> > > +	{ .mbps =  500, .reg = 0x0e },
> > > +	{ .mbps =  550, .reg = 0x2e },
> > > +	{ .mbps =  600, .reg = 0x10 },
> > > +	{ .mbps =  650, .reg = 0x30 },
> > > +	{ .mbps =  700, .reg = 0x12 },
> > > +	{ .mbps =  750, .reg = 0x32 },
> > > +	{ .mbps =  800, .reg = 0x52 },
> > > +	{ .mbps =  850, .reg = 0x72 },
> > > +	{ .mbps =  900, .reg = 0x14 },
> > > +	{ .mbps =  950, .reg = 0x34 },
> > > +	{ .mbps = 1000, .reg = 0x54 },
> > > +	{ .mbps = 1050, .reg = 0x74 },
> > >  	{ .mbps = 1125, .reg = 0x16 },
> > >  	{ /* sentinel */ },
> > >  };
> >
> > --
> > Regards,
> >
> > Laurent Pinchart
> >
> >
> >
>
> --
> Regards,
> Niklas Söderlund

media: rcar-csi2: Fix PHTW table values for E3/V3M

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