mmc: sdhci-msm: get lower bus speed mode for clock scaling
The lower bus speed mode to be used during clock scaling may
vary based on the target. Hence, add a new dtsi property to
define this bus speed mode.
Change-Id: If8e2d125b8246ca479f816a475940bb357138297
Signed-off-by: Sahitya Tummala <stummala@codeaurora.org>
Signed-off-by: Asutosh Das <asutoshd@codeaurora.org>
[xiaonian@codeaurora.org: fixed trivial merge conflicts]
Signed-off-by: Xiaonian Wang <xiaonian@codeaurora.org>
diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c
index bcf33b8..9650085 100644
--- a/drivers/mmc/host/sdhci-msm.c
+++ b/drivers/mmc/host/sdhci-msm.c
@@ -1815,6 +1815,7 @@
int clk_table_len;
u32 *clk_table = NULL;
enum of_gpio_flags flags = OF_GPIO_ACTIVE_LOW;
+ const char *lower_bus_speed = NULL;
pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
if (!pdata) {
@@ -1845,6 +1846,19 @@
!msm_host->mmc->clk_scaling.freq_table_sz)
dev_err(dev, "bad dts clock scaling frequencies\n");
+ /*
+ * Few hosts can support DDR52 mode at the same lower
+ * system voltage corner as high-speed mode. In such cases,
+ * it is always better to put it in DDR mode which will
+ * improve the performance without any power impact.
+ */
+ if (!of_property_read_string(np, "qcom,scaling-lower-bus-speed-mode",
+ &lower_bus_speed)) {
+ if (!strcmp(lower_bus_speed, "DDR52"))
+ msm_host->mmc->clk_scaling.lower_bus_speed_mode |=
+ MMC_SCALING_LOWER_DDR52_MODE;
+ }
+
if (sdhci_msm_dt_get_array(dev, "qcom,clk-rates",
&clk_table, &clk_table_len, 0)) {
dev_err(dev, "failed parsing supported clock rates\n");