diff mbox series

[1/4] mmc: sdhci: Add delay after power off

Message ID 20191202144104.5069-2-jun.nie@linaro.org
State New
Headers show
Series [1/4] mmc: sdhci: Add delay after power off | expand

Commit Message

Jun Nie Dec. 2, 2019, 2:41 p.m. UTC 
Add delay after power off to ensure that full power cycle is
successful. Otherwise, some controllers, at lease for Hisilicon
eMMC controller, may not be unstable sometimes for full power
cycle operation.

Signed-off-by: Jun Nie <jun.nie@linaro.org>

---
 drivers/mmc/host/sdhci.c | 7 +++++++
 drivers/mmc/host/sdhci.h | 2 ++
 2 files changed, 9 insertions(+)

-- 
2.17.1
diff mbox series

Patch

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 3140fe2e5dba..a654f0aeb438 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -1761,6 +1761,13 @@  void sdhci_set_power_noreg(struct sdhci_host *host, unsigned char mode,
 		sdhci_writeb(host, 0, SDHCI_POWER_CONTROL);
 		if (host->quirks2 & SDHCI_QUIRK2_CARD_ON_NEEDS_BUS_ON)
 			sdhci_runtime_pm_bus_off(host);
+
+		/*
+		 * Some controllers need an extra 100ms delay to secure
+		 * full power cycle is successful.
+		 */
+		if (host->quirks2 & SDHCI_QUIRK2_DELAY_AFTER_POWER_OFF)
+			msleep(100);
 	} else {
 		/*
 		 * Spec says that we should clear the power reg before setting
diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
index 0ed3e0eaef5f..0e6f97eaa796 100644
--- a/drivers/mmc/host/sdhci.h
+++ b/drivers/mmc/host/sdhci.h
@@ -482,6 +482,8 @@  struct sdhci_host {
  * block count.
  */
 #define SDHCI_QUIRK2_USE_32BIT_BLK_CNT			(1<<18)
+/* Controllers need an extra 100ms delay to make sure power off completely */
+#define SDHCI_QUIRK2_DELAY_AFTER_POWER_OFF		(1<<19)
 
 	int irq;		/* Device IRQ */
 	void __iomem *ioaddr;	/* Mapped address */