Hi Jaehoon,
On 04/02/21 4:23 am, Jaehoon Chung wrote:
Hi Aswath,
On 2/3/21 3:06 PM, Aswath Govindraju wrote:
Hi Jaehoon,
On 02/02/21 3:40 am, Jaehoon Chung wrote:
Hi Aswath,
On 1/29/21 11:47 PM, Aswath Govindraju wrote:
From: Faiz Abbas faiz_abbas@ti.com
Add a set_voltage() function which handles the switch from 3.3V to 1.8V for SD card UHS modes.
Signed-off-by: Faiz Abbas faiz_abbas@ti.com Signed-off-by: Aswath Govindraju a-govindraju@ti.com
drivers/mmc/sdhci.c | 73 +++++++++++++++++++++++++++++++++++++++++++++ include/sdhci.h | 10 +++++++ 2 files changed, 83 insertions(+)
diff --git a/drivers/mmc/sdhci.c b/drivers/mmc/sdhci.c index 06289343124e..276b6a08e571 100644 --- a/drivers/mmc/sdhci.c +++ b/drivers/mmc/sdhci.c @@ -20,6 +20,7 @@ #include <linux/delay.h> #include <linux/dma-mapping.h> #include <phys2bus.h> +#include <power/regulator.h>
static void sdhci_reset(struct sdhci_host *host, u8 mask) { @@ -509,6 +510,78 @@ void sdhci_set_uhs_timing(struct sdhci_host *host) sdhci_writew(host, reg, SDHCI_HOST_CONTROL2); }
+static void sdhci_set_voltage(struct sdhci_host *host) +{
- if (IS_ENABLED(CONFIG_MMC_IO_VOLTAGE)) {
struct mmc *mmc = (struct mmc *)host->mmc;u32 ctrl;ctrl = sdhci_readw(host, SDHCI_HOST_CONTROL2);switch (mmc->signal_voltage) {case MMC_SIGNAL_VOLTAGE_330:+#if CONFIG_IS_ENABLED(DM_REGULATOR)
if (mmc->vqmmc_supply) {if (regulator_set_enable_if_allowed(mmc->vqmmc_supply, false)) {pr_err("failed to disable vqmmc-supply\n");return;}if (regulator_set_value(mmc->vqmmc_supply, 3300000)) {pr_err("failed to set vqmmc-voltage to 3.3V\n");return;}if (regulator_set_enable_if_allowed(mmc->vqmmc_supply, true)) {pr_err("failed to enable vqmmc-supply\n");return;}}+#endif
/* 3.3V regulator output should be stable within 5 ms */mdelay(5);if (IS_SD(mmc)) {ctrl &= ~SDHCI_CTRL_VDD_180;sdhci_writew(host, ctrl, SDHCI_HOST_CONTROL2);}According to Specification, after Signal bit was changed to 0 from 1, it needs to wait for stable within 5ms. Isn't it right that mdelay(5) locates at here?
I searched the spec for this and found the following line in it,
If this status is not supported, Host Driver should take more than 5ms for stable time of host voltage regulator from changing 1.8V Signaling Enable. Specific Host Driver may use a specific time, which is provided by Host System, instead of using 5ms.This is from the row of "Host Regulator Voltage Stable" in table describing "Present state register", "PartA2_SD Host_Controller_Simplified_Specification_Ver4.20" document, page 66.
The status mentioned is about host regulator voltage stable. Yes I can see that it has been mentioned that host driver has to wait for 5ms after changing the 1.8V signal enable bit. In that case I suppose the same has to be done at [1] as well right ?
Right, i think that it needs to be stable within 5ms.
One more, does it needs to check whether card is SD or not? I think that it doesn't need to check it. Because eMMC needs to switch 1.8V when its mode is upper than DDR, doesn't it?
Voltage switching is not allowed for eMMC and to ensure it, the above mentioned check is done. eMMC operates at the same voltage from the start.
Thanks, Aswath
break;case MMC_SIGNAL_VOLTAGE_180:+#if CONFIG_IS_ENABLED(DM_REGULATOR)
if (mmc->vqmmc_supply) {if (regulator_set_enable_if_allowed(mmc->vqmmc_supply, false)) {pr_err("failed to disable vqmmc-supply\n");return;}if (regulator_set_value(mmc->vqmmc_supply, 1800000)) {pr_err("failed to set vqmmc-voltage to 1.8V\n");return;}if (regulator_set_enable_if_allowed(mmc->vqmmc_supply, true)) {pr_err("failed to enable vqmmc-supply\n");return;}}+#endif
if (IS_SD(mmc)) {ctrl |= SDHCI_CTRL_VDD_180;sdhci_writew(host, ctrl, SDHCI_HOST_CONTROL2);}[1]
For reference, I have also attached the page from where the above line was taken.
Thank you for pointing it out. I will post a re-spin fixing it.
Thanks, Aswath
break;default:/* No signal voltage switch required */return;}- }
+}
+void sdhci_set_control_reg(struct sdhci_host *host) +{
- sdhci_set_voltage(host);
- sdhci_set_uhs_timing(host);
+}
#ifdef CONFIG_DM_MMC static int sdhci_set_ios(struct udevice *dev) { diff --git a/include/sdhci.h b/include/sdhci.h index 3e5a64981857..0ae9471ad749 100644 --- a/include/sdhci.h +++ b/include/sdhci.h @@ -491,6 +491,16 @@ void sdhci_set_uhs_timing(struct sdhci_host *host); /* Export the operations to drivers */ int sdhci_probe(struct udevice *dev); int sdhci_set_clock(struct mmc *mmc, unsigned int clock);
+/**
- sdhci_set_control_reg - Set control registers
- This is used set up control registers for voltage level and UHS speed
- mode.
- @host: SDHCI host structure
- */
+void sdhci_set_control_reg(struct sdhci_host *host); extern const struct dm_mmc_ops sdhci_ops; #else #endif