With preset value enabled, SD clock should be reset before enable
both high speed and UHS-I mode. Current code enable them one by one
and do two continuous times of clock disable/enable. The operation
can be combined into once to save time and make code cleaner.
1. disable clock ->
2. enable high speed (Host Control 1 Register, 0x28<2>) ->
3. enable clock ->
4. disable clock ->
5. enable UHS-I mode (Host Control 2 Register, 0x3E<2:0>) ->
6. enable clock
This patch removed above step 3 and 4.
Signed-off-by: Kevin Liu <kliu5@xxxxxxxxxxx>
---
drivers/mmc/host/sdhci.c | 27 +++++++++------------------
1 file changed, 9 insertions(+), 18 deletions(-)
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index e6da79f..7784756 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -1450,31 +1450,22 @@ static void sdhci_do_set_ios(struct sdhci_host *host, struct mmc_ios *ios)
ctrl_2 |= SDHCI_CTRL_DRV_TYPE_C;
sdhci_writew(host, ctrl_2, SDHCI_HOST_CONTROL2);
- } else {
- /*
- * According to SDHC Spec v3.00, if the Preset Value
- * Enable in the Host Control 2 register is set, we
- * need to reset SD Clock Enable before changing High
- * Speed Enable to avoid generating clock gliches.
- */
-
- /* Reset SD Clock Enable */
- clk = sdhci_readw(host, SDHCI_CLOCK_CONTROL);
- clk &= ~SDHCI_CLOCK_CARD_EN;
- sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);
-
- sdhci_writeb(host, ctrl, SDHCI_HOST_CONTROL);
-
- /* Re-enable SD Clock */
- sdhci_update_clock(host);
}
-
/* Reset SD Clock Enable */
clk = sdhci_readw(host, SDHCI_CLOCK_CONTROL);
clk &= ~SDHCI_CLOCK_CARD_EN;
sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);
+ /*
+ * According to SDHC Spec v3.00, if the Preset Value
+ * Enable in the Host Control 2 register is set, we
+ * need to reset SD Clock Enable before changing High
+ * Speed Enable to avoid generating clock gliches.
+ */
+ if (ctrl_2 & SDHCI_CTRL_PRESET_VAL_ENABLE)
+ sdhci_writeb(host, ctrl, SDHCI_HOST_CONTROL);
+
if (host->ops->set_uhs_signaling)
host->ops->set_uhs_signaling(host, ios->timing);
else {
--
1.7.9.5
--
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