Linux MultiMedia Card development
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From: Erick Shepherd <erick.shepherd@ni.com>
To: <linux-kernel@vger.kernel.org>
Cc: <linux-mmc@vger.kernel.org>, <ulf.hansson@linaro.org>,
	<adrian.hunter@intel.com>, <gratian.crisan@emerson.com>,
	Erick Shepherd <erick.shepherd@ni.com>,
	Kyle Roeschley <kyle.roeschley@ni.com>,
	Brad Mouring <brad.mouring@ni.com>
Subject: [PATCH] mmc: core: Wait for Vdd to settle on card power off
Date: Tue, 11 Feb 2025 15:46:11 -0600	[thread overview]
Message-ID: <20250211214611.469260-1-erick.shepherd@ni.com> (raw)

The SD spec version 6.0 section 6.4.1.5 requires that Vdd must be
lowered to less than 0.5V for a minimum of 1 ms when powering off a
card. Increase our wait to 15 ms so that voltage has time to drain down
to 0.5V.

Signed-off-by: Kyle Roeschley <kyle.roeschley@ni.com>
Signed-off-by: Brad Mouring <brad.mouring@ni.com>
Signed-off-by: Erick Shepherd <erick.shepherd@ni.com>
---
 drivers/mmc/host/sdhci.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index f4a7733a8ad2..b15a1f107549 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -2415,6 +2415,9 @@ void sdhci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
 	else
 		sdhci_set_power(host, ios->power_mode, ios->vdd);
 
+	if (ios->power_mode == MMC_POWER_OFF)
+		mdelay(15);
+
 	if (host->ops->platform_send_init_74_clocks)
 		host->ops->platform_send_init_74_clocks(host, ios->power_mode);
 
-- 
2.43.0


             reply	other threads:[~2025-02-11 21:46 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-02-11 21:46 Erick Shepherd [this message]
2025-02-13 10:22 ` [PATCH] mmc: core: Wait for Vdd to settle on card power off Avri Altman
2025-03-05 18:38 ` Adrian Hunter
2025-03-07 17:46   ` Erick Shepherd
2025-03-07 18:53     ` Adrian Hunter
2025-03-07 21:16       ` Erick Shepherd
2025-03-12 12:44         ` Adrian Hunter
2025-03-13  3:35           ` Erick Shepherd
2025-03-13  8:20             ` Adrian Hunter
2025-03-13 20:44               ` Erick Shepherd
2025-03-14  5:56                 ` Adrian Hunter
  -- strict thread matches above, loose matches on Subject: below --
2017-09-21 17:47 Kyle Roeschley
2017-09-22  9:38 ` Ulf Hansson
2017-09-22 13:57   ` Kyle Roeschley

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