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regulator: twl6030: workaround the VMMC reset behavior 

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@bootlin.com>
Link: https://lore.kernel.org/r/20190725094542.16547-4-gregory.clement@bootlin.com
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Gregory CLEMENT 2019-07-25 11:45:42 +02:00 committed by Mark Brown
parent 621d3ce830
commit d9df0187b6
No known key found for this signature in database
GPG Key ID: 24D68B725D5487D0
1 changed files with 14 additions and 1 deletions
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15
drivers/regulator/twl6030-regulator.c
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@ -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;