During reset the VMMC regulator doesn't reach 0V and only drops to
1.8V, furthermore the pulse width is under 200us whereas the SD
specification expect 1ms.
The WR_S bit allows the TWL6030 to no reset at all the VMMC during warm
reset and keep the current voltage. Thanks to this workaround the SD
card doesn't reach a undefined reset stage.
Actually this behavior is available for all the LDO regulator, so the
driver will also allow to use it with any of these regulator.
Signed-off-by: Gregory CLEMENT <gregory.clement@xxxxxxxxxxx>
---
drivers/regulator/twl6030-regulator.c | 15 ++++++++++++++-
1 file changed, 14 insertions(+), 1 deletion(-)
diff --git a/drivers/regulator/twl6030-regulator.c b/drivers/regulator/twl6030-regulator.c
index d73c81542ceb..b8100c3cedad 100644
--- a/drivers/regulator/twl6030-regulator.c
+++ b/drivers/regulator/twl6030-regulator.c
@@ -57,6 +57,9 @@ struct twlreg_info {
#define VREG_BC_PROC 3
#define VREG_BC_CLK_RST 4
+/* TWL6030 LDO register values for VREG_VOLTAGE */
+#define TWL6030_VREG_VOLTAGE_WR_S BIT(7)
+
/* TWL6030 LDO register values for CFG_STATE */
#define TWL6030_CFG_STATE_OFF 0x00
#define TWL6030_CFG_STATE_ON 0x01
@@ -68,9 +71,10 @@ struct twlreg_info {
#define TWL6030_CFG_STATE_APP(v) (((v) & TWL6030_CFG_STATE_APP_MASK) >>\
TWL6030_CFG_STATE_APP_SHIFT)
-/* Flags for SMPS Voltage reading */
+/* Flags for SMPS Voltage reading and LDO reading*/
#define SMPS_OFFSET_EN BIT(0)
#define SMPS_EXTENDED_EN BIT(1)
+#define TWL_6030_WARM_RESET BIT(3)
/* twl6032 SMPS EPROM values */
#define TWL6030_SMPS_OFFSET 0xB0
@@ -250,6 +254,9 @@ twl6030ldo_set_voltage_sel(struct regulator_dev *rdev, unsigned selector)
{
struct twlreg_info *info = rdev_get_drvdata(rdev);
+ if (info->flags & TWL_6030_WARM_RESET)
+ selector |= TWL6030_VREG_VOLTAGE_WR_S;
+
return twlreg_write(info, TWL_MODULE_PM_RECEIVER, VREG_VOLTAGE,
selector);
}
@@ -259,6 +266,9 @@ static int twl6030ldo_get_voltage_sel(struct regulator_dev *rdev)
struct twlreg_info *info = rdev_get_drvdata(rdev);
int vsel = twlreg_read(info, TWL_MODULE_PM_RECEIVER, VREG_VOLTAGE);
+ if (info->flags & TWL_6030_WARM_RESET)
+ vsel &= ~TWL6030_VREG_VOLTAGE_WR_S;
+
return vsel;
}
@@ -710,6 +720,9 @@ static int twlreg_probe(struct platform_device *pdev)
break;
}
+ if (of_get_property(np, "ti,retain-on-reset", NULL))
+ info->flags |= TWL_6030_WARM_RESET;
+
config.dev = &pdev->dev;
config.init_data = initdata;
config.driver_data = info;
--
2.20.1
