mmc: add power cyle support in mmc core
mmc/sd specification requires vdd to be disabled for 1 ms
and then enabled again during power cycle. Add a
function in mmc core to perform power cycle and set
the io signal to it's initial state.
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>
diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
index 1875b31..0ffe7bf 100644
--- a/drivers/mmc/mmc.c
+++ b/drivers/mmc/mmc.c
@@ -31,6 +31,7 @@
};
static int mmc_set_signal_voltage(struct mmc *mmc, uint signal_voltage);
+static int mmc_power_cycle(struct mmc *mmc);
#if CONFIG_IS_ENABLED(MMC_TINY)
static struct mmc mmc_static;
@@ -1920,14 +1921,6 @@
&mmc->vqmmc_supply);
if (ret)
debug("%s: No vqmmc supply\n", mmc->dev->name);
-
- if (mmc->vmmc_supply) {
- ret = regulator_set_enable(mmc->vmmc_supply, true);
- if (ret) {
- puts("Error enabling VMMC supply\n");
- return ret;
- }
- }
#endif
#else /* !CONFIG_DM_MMC */
/*
@@ -1939,6 +1932,72 @@
return 0;
}
+/*
+ * put the host in the initial state:
+ * - turn on Vdd (card power supply)
+ * - configure the bus width and clock to minimal values
+ */
+static void mmc_set_initial_state(struct mmc *mmc)
+{
+ int err;
+
+ /* First try to set 3.3V. If it fails set to 1.8V */
+ err = mmc_set_signal_voltage(mmc, MMC_SIGNAL_VOLTAGE_330);
+ if (err != 0)
+ err = mmc_set_signal_voltage(mmc, MMC_SIGNAL_VOLTAGE_180);
+ if (err != 0)
+ printf("mmc: failed to set signal voltage\n");
+
+ mmc_select_mode(mmc, MMC_LEGACY);
+ mmc_set_bus_width(mmc, 1);
+ mmc_set_clock(mmc, 0);
+}
+
+static int mmc_power_on(struct mmc *mmc)
+{
+#if CONFIG_IS_ENABLED(DM_MMC) && CONFIG_IS_ENABLED(DM_REGULATOR)
+ if (mmc->vmmc_supply) {
+ int ret = regulator_set_enable(mmc->vmmc_supply, true);
+
+ if (ret) {
+ puts("Error enabling VMMC supply\n");
+ return ret;
+ }
+ }
+#endif
+ return 0;
+}
+
+static int mmc_power_off(struct mmc *mmc)
+{
+#if CONFIG_IS_ENABLED(DM_MMC) && CONFIG_IS_ENABLED(DM_REGULATOR)
+ if (mmc->vmmc_supply) {
+ int ret = regulator_set_enable(mmc->vmmc_supply, false);
+
+ if (ret) {
+ puts("Error disabling VMMC supply\n");
+ return ret;
+ }
+ }
+#endif
+ return 0;
+}
+
+static int mmc_power_cycle(struct mmc *mmc)
+{
+ int ret;
+
+ ret = mmc_power_off(mmc);
+ if (ret)
+ return ret;
+ /*
+ * SD spec recommends at least 1ms of delay. Let's wait for 2ms
+ * to be on the safer side.
+ */
+ udelay(2000);
+ return mmc_power_on(mmc);
+}
+
int mmc_start_init(struct mmc *mmc)
{
bool no_card;
@@ -1967,6 +2026,10 @@
if (err)
return err;
+ err = mmc_power_on(mmc);
+ if (err)
+ return err;
+
#if CONFIG_IS_ENABLED(DM_MMC)
/* The device has already been probed ready for use */
#else
@@ -1977,16 +2040,7 @@
#endif
mmc->ddr_mode = 0;
- /* First try to set 3.3V. If it fails set to 1.8V */
- err = mmc_set_signal_voltage(mmc, MMC_SIGNAL_VOLTAGE_330);
- if (err != 0)
- err = mmc_set_signal_voltage(mmc, MMC_SIGNAL_VOLTAGE_180);
- if (err != 0)
- printf("failed to set signal voltage\n");
-
- mmc_set_bus_width(mmc, 1);
- mmc_set_clock(mmc, 1);
-
+ mmc_set_initial_state(mmc);
mmc_send_init_stream(mmc);
/* Reset the Card */