On 2016/6/21 13:35, Jaehoon Chung wrote:
If there ins no vqmmc, voltage should not be changed.
Then it nees to maintain the previous status for USH_REG register.
To use the standard spec, it should be returned error when voltage
can't switch.
Note:
Dwmmc controller will not make any exception case.(like exynos.)
If card isn't working well after appling this patch, it needs to check
the regulator side.
Signed-off-by: Jaehoon Chung <jh80.chung@xxxxxxxxxxx>
---
Changelog V2:
-Fix the typo
drivers/mmc/host/dw_mmc.c | 40 ++++++++++++++++++++++------------------
1 file changed, 22 insertions(+), 18 deletions(-)
diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
index ec3f0a8..56c48fb 100644
--- a/drivers/mmc/host/dw_mmc.c
+++ b/drivers/mmc/host/dw_mmc.c
@@ -1404,33 +1404,37 @@ static int dw_mci_switch_voltage(struct mmc_host *mmc, struct mmc_ios *ios)
struct dw_mci_slot *slot = mmc_priv(mmc);
struct dw_mci *host = slot->host;
const struct dw_mci_drv_data *drv_data = host->drv_data;
- u32 uhs;
+ u32 uhs = 0;
u32 v18 = SDMMC_UHS_18V << slot->id;
int ret;
if (drv_data && drv_data->switch_voltage)
return drv_data->switch_voltage(mmc, ios);
- /*
- * Program the voltage. Note that some instances of dw_mmc may use
- * the UHS_REG for this. For other instances (like exynos) the UHS_REG
- * does no harm but you need to set the regulator directly. Try both.
- */
+ if (IS_ERR(mmc->supply.vqmmc)) {
+ dev_dbg(&mmc->class_dev,
+ "vqmmc not available.(Skip the switching voltage)\n");
+ return -EINVAL;
+ }
+
+ ret = mmc_regulator_set_vqmmc(mmc, ios);
+ if (ret) {
+ dev_err(&mmc->class_dev,
+ "Regulator set error %d - %s V\n",
+ ret, uhs & v18 ? "1.8" : "3.3");
+ return ret;
+ }
+
uhs = mci_readl(host, UHS_REG);
- if (ios->signal_voltage == MMC_SIGNAL_VOLTAGE_330)
uhs is still zero now, so maybe we can remove this switch branch and
only need a simple checking like this:
if (ios->signal_voltage == MMC_SIGNAL_VOLTAGE_180)
uhs |= v18;
otherwise, it looks good to me.
+ switch (ios->signal_voltage) {
+ case MMC_SIGNAL_VOLTAGE_330:
uhs &= ~v18;
- else
+ break;
+ case MMC_SIGNAL_VOLTAGE_180:
uhs |= v18;
-
- if (!IS_ERR(mmc->supply.vqmmc)) {
- ret = mmc_regulator_set_vqmmc(mmc, ios);
-
- if (ret) {
- dev_dbg(&mmc->class_dev,
- "Regulator set error %d - %s V\n",
- ret, uhs & v18 ? "1.8" : "3.3");
- return ret;
- }
+ break;
+ default:
+ uhs &= ~v18;
}
mci_writel(host, UHS_REG, uhs);
--
Best Regards
Shawn Lin
--
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