linux-kernel - [PATCH v4 1/2] mmc: sdhci: Add a quirk for suppressing V1P8_SIGNAL

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Message-ID: <20250424180036.1541568-2-jm@ti.com>
Date: Thu, 24 Apr 2025 13:00:35 -0500
From: Judith Mendez <jm@...com>
To: Judith Mendez <jm@...com>, Adrian Hunter <adrian.hunter@...el.com>,
        Ulf
 Hansson <ulf.hansson@...aro.org>
CC: Josua Mayer <josua@...id-run.com>, <linux-mmc@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, Nishanth Menon <nm@...com>,
        Francesco Dolcini
	<francesco@...cini.it>,
        Hiago De Franco <hiagofranco@...il.com>, Moteen Shah
	<m-shah@...com>
Subject: [PATCH v4 1/2] mmc: sdhci: Add a quirk for suppressing V1P8_SIGNAL_ENA

There are init failures across Kingston eMMC and SD cards like Microcenter
and Patriot due to the sequence of when V1P8_SIGNAL_ENA is set. Since it
is not always required, add a quirk SDHCI_QUIRK2_SUPPRESS_V1P8_ENA which
allows users with init failures to suppress V1P8_SIGNAL_ENA.

Fixes: ac5a41b472b4 ("Revert "mmc: sdhci_am654: Add sdhci_am654_start_signal_voltage_switch"")
Fixes: 941a7abd4666 ("mmc: sdhci_am654: Add sdhci_am654_start_signal_voltage_switch")
Cc: stable@...r.kernel.org
Signed-off-by: Judith Mendez <jm@...com>
---
 drivers/mmc/host/sdhci.c | 8 +++++---
 drivers/mmc/host/sdhci.h | 2 ++
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index fd5681d1e31f..ef66dede8d09 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -2698,8 +2698,10 @@ int sdhci_start_signal_voltage_switch(struct mmc_host *mmc,
 		 * Enable 1.8V Signal Enable in the Host Control2
 		 * register
 		 */
-		ctrl |= SDHCI_CTRL_VDD_180;
-		sdhci_writew(host, ctrl, SDHCI_HOST_CONTROL2);
+		if (!(host->quirks2 & SDHCI_QUIRK2_SUPPRESS_V1P8_ENA)) {
+			ctrl |= SDHCI_CTRL_VDD_180;
+			sdhci_writew(host, ctrl, SDHCI_HOST_CONTROL2);
+		}
 
 		/* Some controller need to do more when switching */
 		if (host->ops->voltage_switch)
@@ -2707,7 +2709,7 @@ int sdhci_start_signal_voltage_switch(struct mmc_host *mmc,
 
 		/* 1.8V regulator output should be stable within 5 ms */
 		ctrl = sdhci_readw(host, SDHCI_HOST_CONTROL2);
-		if (ctrl & SDHCI_CTRL_VDD_180)
+		if (ctrl & SDHCI_CTRL_VDD_180 || (host->quirks2 & SDHCI_QUIRK2_SUPPRESS_V1P8_ENA))
 			return 0;
 
 		pr_warn("%s: 1.8V regulator output did not become stable\n",
diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
index cd0e35a80542..60e180456ccc 100644
--- a/drivers/mmc/host/sdhci.h
+++ b/drivers/mmc/host/sdhci.h
@@ -536,6 +536,8 @@ struct sdhci_host {
 #define SDHCI_QUIRK2_USE_32BIT_BLK_CNT			(1<<18)
 /* Issue CMD and DATA reset together */
 #define SDHCI_QUIRK2_ISSUE_CMD_DAT_RESET_TOGETHER	(1<<19)
+/* Suppress setting V1P8_SIGNAL_ENA */
+#define SDHCI_QUIRK2_SUPPRESS_V1P8_ENA			(1<<20)
 
 	int irq;		/* Device IRQ */
 	void __iomem *ioaddr;	/* Mapped address */
-- 
2.49.0