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regulator: twl6030: workaround the VMMC reset behavior

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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;