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Commit 0410f7ac authored by Suresh Udipi's avatar Suresh Udipi Committed by Greg Kroah-Hartman
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media: rcar-csi2: Correct the selection of hsfreqrange 



[ Upstream commit cee44d4fbacbbdfe62697ec94e76c6e4f726c5df ]

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: 769afd21 ("media: rcar-csi2: add Renesas R-Car MIPI CSI-2 receiver driver")
Signed-off-by: default avatarSuresh Udipi <sudipi@jp.adit-jv.com>
Signed-off-by: default avatarKazuyoshi Akiyama <akiyama@nds-osk.co.jp>
Signed-off-by: default avatarMichael Rodin <mrodin@de.adit-jv.com>
Reviewed-by: default avatarNiklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Signed-off-by: default avatarHans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 62866d65

drivers/media/platform/rcar-vin/rcar-csi2.c

+8 −1
Original line number Diff line number Diff line
@@ -430,16 +430,23 @@ 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;