[U-Boot] [PATCH V3 3/4] mmc: tmio: Keep generating clock when clock are enabled

Marek Vasut marek.vasut at gmail.com
Mon Nov 5 21:45:50 UTC 2018


The TMIO core has a feature where it can automatically disable clock output
when the bus is not in use. While this is useful, it also interferes with
switching the bus to 1.8V and other background tasks of the SD/MMC cards,
which require clock to be enabled.

This patch respects the mmc->clk_disable and only disables the clock when
the MMC core requests it. Otherwise the clock are continuously generated
on the bus.

Signed-off-by: Marek Vasut <marek.vasut+renesas at gmail.com>
Cc: Masahiro Yamada <yamada.masahiro at socionext.com>
---
 drivers/mmc/tmio-common.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/mmc/tmio-common.c b/drivers/mmc/tmio-common.c
index 424b60ce52..fad2816ca5 100644
--- a/drivers/mmc/tmio-common.c
+++ b/drivers/mmc/tmio-common.c
@@ -612,10 +612,16 @@ static void tmio_sd_set_clk_rate(struct tmio_sd_priv *priv,
 	tmio_sd_writel(priv, tmp, TMIO_SD_CLKCTL);
 
 	tmp &= ~TMIO_SD_CLKCTL_DIV_MASK;
-	tmp |= val | TMIO_SD_CLKCTL_OFFEN;
+	tmp |= val;
 	tmio_sd_writel(priv, tmp, TMIO_SD_CLKCTL);
 
-	tmp |= TMIO_SD_CLKCTL_SCLKEN;
+	if (!mmc->clk_disable) {
+		tmp &= ~TMIO_SD_CLKCTL_OFFEN;
+		tmp |= TMIO_SD_CLKCTL_SCLKEN;
+	} else {
+		tmp |= TMIO_SD_CLKCTL_OFFEN;
+		tmp &= ~TMIO_SD_CLKCTL_SCLKEN;
+	}
 	tmio_sd_writel(priv, tmp, TMIO_SD_CLKCTL);
 
 	udelay(1000);
-- 
2.18.0



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