1 files changed, 25 insertions, 1 deletions

diff --git a/firmware/target/arm/as3525/sd-as3525v2.c b/firmware/target/arm/as3525/sd-as3525v2.c
index b512cc2ea4..d27df5289c 100644
--- a/firmware/target/arm/as3525/sd-as3525v2.c
+++ b/firmware/target/arm/as3525/sd-as3525v2.c
@@ -488,7 +488,7 @@ static int sd_init_card(const int drive)
     card_info[drive].initialized = 0;
     card_info[drive].rca = 0;
 
-    /*  assume 24 MHz clock / 60 = 400 kHz  */
+    /*  assume 24 MHz clock / (2x)60 = 200 kHz  */
     MCI_CLKDIV = (MCI_CLKDIV & ~(0xFF)) | 0x3C;    /* CLK_DIV_0 : bits 7:0  */
 
     /* 100 - 400kHz clock required for Identification Mode  */
@@ -957,3 +957,27 @@ int sd_event(long id, intptr_t data)
 
     return rc;
 }
+
+#if defined(CONFIG_POWER_SAVING) && (CONFIG_POWER_SAVING & POWERSV_DISK)
+/* declared in system-as3525.c */
+void ams_sd_set_low_speed(bool slow)
+{
+    /* block access while speed is changed */
+    mutex_lock(&sd_mtx);
+    enable_controller(true);
+    if (slow)
+    {
+        CGU_SDSLOT = (CGU_SDSLOT & ~(0xF << 2)) | (AS3525_SDSLOT_DIV_MAX << 2);
+        /* power save is enabled for the sd card(s) ASSUMES CRD0 is int drive! */
+        MCI_CLKENA |= (CCLK_LP_CRD1 | CCLK_LP_CRD2 | CCLK_LP_CRD3);
+    }
+    else
+    {
+        /* Full Speed */
+        CGU_SDSLOT = (CGU_SDSLOT & ~(0xF << 2)) | (AS3525_SDSLOT_DIV << 2);
+        MCI_CLKENA = (MCI_CLKENA & ~(CCLK_LP_CRD1 | CCLK_LP_CRD2 | CCLK_LP_CRD3));
+    }
+    enable_controller(false);
+    mutex_unlock(&sd_mtx);
+}
+#endif