linux-kernel - [PATCH] mmc: dw_mmc: Don't send clock off command if power is off

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Message-Id: <1426874420-25103-1-git-send-email-dianders@chromium.org>
Date:	Fri, 20 Mar 2015 11:00:20 -0700
From:	Doug Anderson <dianders@...omium.org>
To:	Jaehoon Chung <jh80.chung@...sung.com>,
	Seungwon Jeon <tgih.jun@...sung.com>,
	Ulf Hansson <ulf.hansson@...aro.org>
Cc:	Alim Akhtar <alim.akhtar@...sung.com>,
	Sonny Rao <sonnyrao@...omium.org>,
	Andrew Bresticker <abrestic@...omium.org>,
	Heiko Stuebner <heiko@...ech.de>,
	Addy Ke <addy.ke@...k-chips.com>,
	Alexandru Stan <amstan@...omium.org>,
	javier.martinez@...labora.co.uk,
	linux-arm-kernel@...ts.infradead.org,
	linux-rockchip@...ts.infradead.org,
	Doug Anderson <dianders@...omium.org>, chris@...ntf.net,
	linux-mmc@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH] mmc: dw_mmc: Don't send clock off command if power is off

We've already seen that it causes failures if we try to send the
"SDMMC_CMD_UPD_CLK" command when power is off to the system.  Here's
another case where we were doing it: we were sending an
SDMMC_CMD_UPD_CLK to set the clock to 0 when the card was already
powered off and the clock was already at 0.  Let's avoid that command
and avoid problems.

Signed-off-by: Doug Anderson <dianders@...omium.org>
---
 drivers/mmc/host/dw_mmc.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
index 47dfd0e..aeec698 100644
--- a/drivers/mmc/host/dw_mmc.c
+++ b/drivers/mmc/host/dw_mmc.c
@@ -1172,8 +1172,9 @@ static void dw_mci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
 
 		break;
 	case MMC_POWER_OFF:
-		/* Turn clock off before power goes down */
-		dw_mci_setup_bus(slot, false);
+		/* Turn clock off before power goes down; only if powered */
+		if (slot->host->vqmmc_enabled)
+			dw_mci_setup_bus(slot, false);
 
 		if (!IS_ERR(mmc->supply.vmmc))
 			mmc_regulator_set_ocr(mmc, mmc->supply.vmmc, 0);
-- 
2.2.0.rc0.207.ga3a616c

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