From: "Niklas Söderlund" <niklas.soderlund@ragnatech.se>
To: Suresh Udipi <sudipi@jp.adit-jv.com>
Cc: mrodin@de.adit-jv.com, akiyama@nds-osk.co.jp,
efriedrich@de.adit-jv.com, erosca@de.adit-jv.com,
linux-kernel@vger.kernel.org, linux-media@vger.kernel.org,
linux-renesas-soc@vger.kernel.org, mchehab@kernel.org,
michael@rodin.online, securitycheck@denso.co.jp
Subject: Re: [PATCH v8 1/3] media: rcar-csi2: Correct the selection of hsfreqrange
Date: Wed, 1 Jul 2020 00:03:53 +0200 [thread overview]
Message-ID: <20200630220353.GJ2365286@oden.dyn.berto.se> (raw)
In-Reply-To: <1592476472-26235-1-git-send-email-sudipi@jp.adit-jv.com>
Hi Suresh,
Thanks for your work.
On 2020-06-18 19:34:30 +0900, Suresh Udipi wrote:
> hsfreqrange should be chosen based on the calculated mbps which
> is closer to the default bit rate and within the range as per
> table[1]. But current calculation always selects first value which
> is greater than or equal to the calculated mbps which may lead
> to chosing a wrong range in some cases.
>
> For example for 360 mbps for H3/M3N
> Existing logic selects
> Calculated value 360Mbps : Default 400Mbps Range [368.125 -433.125 mbps]
>
> This hsfreqrange is out of range.
>
> The logic is changed to get the default value which is closest to the
> calculated value [1]
>
> Calculated value 360Mbps : Default 350Mbps Range [320.625 -380.625 mpbs]
>
> [1] specs r19uh0105ej0200-r-car-3rd-generation.pdf [Table 25.9]
>
> Please note that According to Renesas in Table 25.9 the range for
> 220 default value is corrected as below
>
> |Range (Mbps) | Default Bit rate (Mbps) |
> -----------------------------------------------
> | 197.125-244.125 | 220 |
> -----------------------------------------------
>
> Fixes: 769afd212b16 ("media: rcar-csi2: add Renesas R-Car MIPI CSI-2 receiver driver")
>
> Signed-off-by: Suresh Udipi <sudipi@jp.adit-jv.com>
> Signed-off-by: Kazuyoshi Akiyama <akiyama@nds-osk.co.jp>
> Signed-off-by: Michael Rodin <mrodin@de.adit-jv.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
> ---
> Changes in v2:
> - Added the boundary check for the maximum bit rate.
>
> - Simplified the logic by remmoving range check
> as only the closest default value covers most
> of the use cases.
>
> - Aligning the commit message based on the above change
>
>
> Changes in v3:
> - Added max member from struct rcsi2_mbps_reg.
> mbps varialbe cannot be removed from rcsi2_mbps_reg,
> since this structure is reused for
> phtw_mbps_h3_v3h_m3n/phtw_mbps_v3m_e3 where mbps is
> used.
>
>
> - Update the walk of the array in rcsi2_set_phypll() so that it finds
> the first entry where the calculated bit rate is less than the max.
>
> - Support lower bit rates less than 80Mbps like 48Mbps
> (Raspberry pi camera 640x480 connected to Kingfisher)
> can also be supported by selecting the lowest default bit rate 80Mbps
> as done before this fix
>
> - Alignement of the commit message based on above changes.
>
> Changes in v4:
> - Remove unncessary braces.
>
> Changes in v5:
> - Removed mbps variable in rcsi2_mbps_reg and aligned all
> tables accordingly
>
>
> Changes in v6
> - Renesas correct the range of default value 220Mbps. Now
> if we select the nearest value to the default value all
> the values are in range. So reverting back to original patch
>
> - Added warning for values less than Minimum 80Mbps
>
> Changes in v7
> - Create a seperate commit for the warning message less
> than minimum 80Mbps
>
> - Reorder the statements to increase readability
>
> Changes in v8
> - Extended the logic of selection of nearest mbps to
> PHTW registers value less than 250Mbps. A new commit
> is added
>
> drivers/media/platform/rcar-vin/rcar-csi2.c | 9 ++++++++-
> 1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/media/platform/rcar-vin/rcar-csi2.c b/drivers/media/platform/rcar-vin/rcar-csi2.c
> index 151e6a9..f18dedc 100644
> --- a/drivers/media/platform/rcar-vin/rcar-csi2.c
> +++ b/drivers/media/platform/rcar-vin/rcar-csi2.c
> @@ -431,16 +431,23 @@ static int rcsi2_wait_phy_start(struct rcar_csi2 *priv)
> static int rcsi2_set_phypll(struct rcar_csi2 *priv, unsigned int mbps)
> {
> const struct rcsi2_mbps_reg *hsfreq;
> + const struct rcsi2_mbps_reg *hsfreq_prev = NULL;
>
> - for (hsfreq = priv->info->hsfreqrange; hsfreq->mbps != 0; hsfreq++)
> + for (hsfreq = priv->info->hsfreqrange; hsfreq->mbps != 0; hsfreq++) {
> if (hsfreq->mbps >= mbps)
> break;
> + hsfreq_prev = hsfreq;
> + }
>
> if (!hsfreq->mbps) {
> dev_err(priv->dev, "Unsupported PHY speed (%u Mbps)", mbps);
> return -ERANGE;
> }
>
> + if (hsfreq_prev &&
> + ((mbps - hsfreq_prev->mbps) <= (hsfreq->mbps - mbps)))
> + hsfreq = hsfreq_prev;
> +
> rcsi2_write(priv, PHYPLL_REG, PHYPLL_HSFREQRANGE(hsfreq->reg));
>
> return 0;
> --
> 2.7.4
>
--
Regards,
Niklas Söderlund
next prev parent reply other threads:[~2020-06-30 22:04 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-20 4:49 [PATCH] [RFC] media: rcar-csi2: Corrects the selection of hsfreqrange Suresh Udipi
2020-03-04 19:46 ` Niklas Söderlund
2020-03-16 13:02 ` Niklas Söderlund
2020-03-17 7:08 ` [PATCH v2] [RFC] rcar-vin: rcar-csi2: Correct " Suresh Udipi
2020-03-17 10:37 ` Niklas Söderlund
2020-03-18 9:00 ` Suresh Udipi
2020-03-18 10:19 ` Niklas Söderlund
2020-03-20 8:00 ` [PATCH v3] media: " Suresh Udipi
2020-03-23 4:48 ` [PATCH v4] " Suresh Udipi
2020-04-14 11:56 ` Niklas Söderlund
2020-04-30 6:03 ` [PATCH v5] " Suresh Udipi
2020-05-04 15:01 ` Michael Rodin
2020-05-12 21:30 ` Niklas Söderlund
2020-05-27 15:47 ` Michael Rodin
2020-05-27 16:16 ` [PATCH] rcar-vin: " Michael Rodin
2020-06-05 18:44 ` Michael Rodin
2020-06-08 3:25 ` [PATCH v6] media: " Suresh Udipi
2020-06-10 13:40 ` Niklas Söderlund
2020-06-12 3:10 ` Suresh Udipi
2020-06-12 17:28 ` Michael Rodin
2020-06-15 14:11 ` Niklas Söderlund
2020-06-17 4:57 ` [PATCH v7 1/2] " Suresh Udipi
2020-06-17 4:57 ` [PATCH v7 2/2] media: rcar-csi2: Add warning for PHY speed less than minimum Suresh Udipi
2020-06-17 13:37 ` [PATCH v7 1/2] media: rcar-csi2: Correct the selection of hsfreqrange Michael Rodin
2020-06-18 10:34 ` [PATCH v8 1/3] " Suresh Udipi
2020-06-18 10:34 ` [PATCH v8 2/3] media: rcar-csi2: Add warning for PHY speed less than minimum Suresh Udipi
2020-06-30 22:05 ` Niklas Söderlund
2020-06-18 10:34 ` [PATCH v8 3/3] media: rcar-csi2: Optimize the selection PHTW register Suresh Udipi
2020-06-30 22:08 ` Niklas Söderlund
2020-07-01 9:52 ` [PATCH v9 1/3] media: rcar-csi2: Correct the selection of hsfreqrange Suresh Udipi
2020-07-01 9:53 ` [PATCH v9 2/3] media: rcar-csi2: Add warning for PHY speed less than minimum Suresh Udipi
2020-07-01 9:53 ` [PATCH v9 3/3] media: rcar-csi2: Optimize the selection PHTW register Suresh Udipi
2020-06-30 22:03 ` Niklas Söderlund [this message]
2020-05-27 16:17 ` [PATCH] rcar-vin: rcar-csi2: Select the correct " Michael Rodin
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