[PATCH 1/2] drivers: mmc: add quirk SDHCI_QUIRK_CLOCK_DIV_ZERO_BROKEN

[Suneel Garapati]

adds quirk for controllers whose clock divider zero is broken,
sdhci_set_clock function will incorporate this modification.

Signed-off-by: Suneel Garapati <suneel.garapati@xxxxxxxxxx>
---
 drivers/mmc/host/sdhci.c | 4 ++++
 drivers/mmc/host/sdhci.h | 2 ++
 2 files changed, 6 insertions(+)

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 1b4861d..087327e 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -1210,6 +1210,10 @@ void sdhci_set_clock(struct sdhci_host *host, unsigned int clock)
			}
			real_div = div;
			div >>= 1;
+			if ((host->quirks2 & SDHCI_QUIRK2_CLOCK_DIV_ZERO_BROKEN)
+				&& !div && host->max_clk <= 25000000) {
+				div = 1;
+			}
		}
	} else {
		/* Version 2.00 divisors must be a power of 2. */
diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
index 5521d29..67046ca 100644
--- a/drivers/mmc/host/sdhci.h
+++ b/drivers/mmc/host/sdhci.h
@@ -409,6 +409,8 @@ struct sdhci_host {
 #define SDHCI_QUIRK2_SUPPORT_SINGLE			(1<<13)
 /* Controller broken with using ACMD23 */
 #define SDHCI_QUIRK2_ACMD23_BROKEN			(1<<14)
+/* Broken Clock divider zero in controller */
+#define SDHCI_QUIRK2_CLOCK_DIV_ZERO_BROKEN		(1<<15)

	int irq;		/* Device IRQ */
	void __iomem *ioaddr;	/* Mapped address */
--
2.1.2
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