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From: Artem Shimko <a.shimko.dev@gmail.com>
To: andriy.shevchenko@intel.com, adrian.hunter@intel.com,
	ulfh@kernel.org, p.zabel@pengutronix.de
Cc: Artem Shimko <a.shimko.dev@gmail.com>,
	linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH 1/3] mmc: sdhci-of-dwcmshc: improve delay handling with fsleep()
Date: Mon, 18 May 2026 14:00:31 +0300	[thread overview]
Message-ID: <20260518110034.142587-2-a.shimko.dev@gmail.com> (raw)
In-Reply-To: <20260518110034.142587-1-a.shimko.dev@gmail.com>

The driver currently uses udelay() for short delays, which performs
busy-waiting and may not be optimal even for very short durations.
While udelay() is appropriate for atomic context, these specific delays
occur in non-atomic contexts where sleeping is allowed.

Replace udelay(1) with fsleep(1) in dwcmshc_rk3568_set_clock() and
rk35xx_sdhci_reset(). The fsleep() function automatically selects the
optimal delay mechanism based on the requested duration - for
delays <= 10 microseconds it will use udelay() internally, but provides
better flexibility for future adjustments and makes the code more
consistent with kernel best practices. No functional change is intended.

Signed-off-by: Artem Shimko <a.shimko.dev@gmail.com>
---
 drivers/mmc/host/sdhci-of-dwcmshc.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/mmc/host/sdhci-of-dwcmshc.c b/drivers/mmc/host/sdhci-of-dwcmshc.c
index 0b2158a7e409..8c3ca47c8060 100644
--- a/drivers/mmc/host/sdhci-of-dwcmshc.c
+++ b/drivers/mmc/host/sdhci-of-dwcmshc.c
@@ -816,7 +816,7 @@ static void dwcmshc_rk3568_set_clock(struct sdhci_host *host, unsigned int clock
 
 	/* Reset DLL */
 	sdhci_writel(host, BIT(1), DWCMSHC_EMMC_DLL_CTRL);
-	udelay(1);
+	fsleep(1);
 	sdhci_writel(host, 0x0, DWCMSHC_EMMC_DLL_CTRL);
 
 	/*
@@ -895,7 +895,7 @@ static void rk35xx_sdhci_reset(struct sdhci_host *host, u8 mask)
 
 	if (mask & SDHCI_RESET_ALL && priv->reset) {
 		reset_control_assert(priv->reset);
-		udelay(1);
+		fsleep(1);
 		reset_control_deassert(priv->reset);
 	}
 
-- 
2.43.0


  reply	other threads:[~2026-05-18 11:00 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-05-18 11:00 [PATCH 0/3] mmc: sdhci-of-dwcmshc: Minor cleanups Artem Shimko
2026-05-18 11:00 ` Artem Shimko [this message]
2026-05-18 14:16   ` [PATCH 1/3] mmc: sdhci-of-dwcmshc: improve delay handling with fsleep() Andy Shevchenko
2026-05-18 14:50     ` Artem Shimko
2026-05-18 18:35       ` Andy Shevchenko
2026-05-19 15:43         ` Artem Shimko
2026-05-18 11:00 ` [PATCH 2/3] mmc: sdhci-of-dwcmshc: remove redundant IS_ERR() check Artem Shimko
2026-05-20  6:18   ` Adrian Hunter
2026-05-18 11:00 ` [PATCH 3/3] mmc: sdhci-of-dwcmshc: use dev_err_probe() to simplify error paths Artem Shimko
2026-05-20  6:18   ` Adrian Hunter
2026-05-20  7:14     ` Artem Shimko

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