[PATCH 24/30] mci: imx-esdhc: don't reconfigure clock unless required

[Ahmad Fatoum]

The Linux SDHCI driver skips sdhci_ops::set_clock if the clock rate is
not going to change. Let's do the same in barebox with the slight
difference that we also check for whether DDR settings have changed,
because that influences the clock configuration on the eSDHC.

Signed-off-by: Ahmad Fatoum <a.fatoum at pengutronix.de>
---
 drivers/mci/imx-esdhc.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/mci/imx-esdhc.c b/drivers/mci/imx-esdhc.c
index 751b3703e579..eb24f49008f6 100644
--- a/drivers/mci/imx-esdhc.c
+++ b/drivers/mci/imx-esdhc.c
@@ -226,6 +226,7 @@ static void layerscape_set_timing(struct fsl_esdhc_host *host, enum mci_timing t
 static void esdhc_set_ios(struct mci_host *mci, struct mci_ios *ios)
 {
 	struct fsl_esdhc_host *host = to_fsl_esdhc(mci);
+	bool ddr_changed = false;
 
 	/*
 	 * call esdhc_set_timing() before update the clock rate,
@@ -235,14 +236,18 @@ static void esdhc_set_ios(struct mci_host *mci, struct mci_ios *ios)
 	 * setting clock rate.
 	 */
 	if (host->sdhci.timing != ios->timing) {
+		if (mci_timing_is_ddr(host->sdhci.timing) != mci_timing_is_ddr(ios->timing))
+			ddr_changed = true;
+
 		if (esdhc_is_usdhc(host))
 			usdhc_set_timing(host, ios->timing);
 		else if (esdhc_is_layerscape(host))
 			layerscape_set_timing(host, ios->timing);
 	}
 
-	/* Set the clock speed */
-	set_sysctl(mci, ios->clock, mci_timing_is_ddr(ios->timing));
+	/* Reconfigure clock if requested speed changes */
+	if (!ios->clock || mci->actual_clock != ios->clock || ddr_changed)
+		set_sysctl(mci, ios->clock, mci_timing_is_ddr(ios->timing));
 
 	sdhci_set_drv_type(&host->sdhci, ios->drv_type);
 
-- 
2.39.5