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From:   Srinivasarao Pathipati <quic_spathi@quicinc.com>
To:     ulf.hansson@linaro.org, avri.altman@wdc.com,
        linus.walleij@linaro.org, vbadigan@codeaurora.org,
        shawn.lin@rock-chips.com, s.shtylyov@omp.ru, merez@codeaurora.org,
        wsa+renesas@sang-engineering.com, briannorris@chromium.org,
        sayalil@codeaurora.org, linux-mmc@vger.kernel.org,
        linux-kernel@vger.kernel.org
Cc:     Kishor Krishna Bhat <quic_kishkris@quicinc.com>,
        kamasali <quic_kamasali@quicinc.com>,
        Srinivasarao Pathipati <quic_spathi@quicinc.com>
Subject: [PATCH V1] mmc: core: Select HS mode in device first and then in the host
Date:   Tue, 26 Apr 2022 14:45:32 +0530
Message-Id: <1650964532-9379-1-git-send-email-quic_spathi@quicinc.com>
Precedence: bulk

From: Sayali Lokhande <sayalil@codeaurora.org>

While switching from hs400 to hs200 mode, high speed mode
timing should be selected in the device before changing the
clock frequency in the host. But current implementation,
(mmc_hs400_to_hs200) first updates the frequency in the host
and then updates mode in the device. This is a spec violation.
Hence update the sequence to comply with the spec.

Signed-off-by: Veerabhadrarao Badiganti <vbadigan@codeaurora.org>
Signed-off-by: Sayali Lokhande <sayalil@codeaurora.org>
Signed-off-by: Kishor Krishna Bhat <quic_kishkris@quicinc.com>
Signed-off-by: kamasali <quic_kamasali@quicinc.com>
Signed-off-by: Srinivasarao Pathipati <quic_spathi@quicinc.com>
---
 drivers/mmc/core/mmc.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index 8691c00..b4bcebc 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -1259,10 +1259,6 @@ int mmc_hs400_to_hs200(struct mmc_card *card)
 	int err;
 	u8 val;
 
-	/* Reduce frequency to HS */
-	max_dtr = card->ext_csd.hs_max_dtr;
-	mmc_set_clock(host, max_dtr);
-
 	/* Switch HS400 to HS DDR */
 	val = EXT_CSD_TIMING_HS;
 	err = __mmc_switch(card, EXT_CSD_CMD_SET_NORMAL, EXT_CSD_HS_TIMING,
@@ -1276,6 +1272,10 @@ int mmc_hs400_to_hs200(struct mmc_card *card)
 
 	mmc_set_timing(host, MMC_TIMING_MMC_DDR52);
 
+	/* Reduce frequency to HS */
+	max_dtr = card->ext_csd.hs_max_dtr;
+	mmc_set_clock(host, max_dtr);
+
 	err = mmc_switch_status(card, true);
 	if (err)
 		goto out_err;
-- 
2.7.4