| Message ID | 41cb1b4dac3a15595c89fa962b78d3f68f370021.1543245984.git-series.plaes@plaes.org (mailing list archive) |
|---|---|
| State | Not Applicable, archived |
| Headers | show |
| Series | regulator: axp20x: Stop AXP209 from crashing when enabling LDO3 | expand |
On Mon, Nov 26, 2018 at 05:27:47PM +0200, Priit Laes wrote: > From: Olliver Schinagl <oliver@schinagl.nl> > > In the past, there have been words on various lists that if LDO3 is > disabled in u-boot, but enabled in the DTS, the axp209 driver would > fail to continue/hang. Several enable/disable patches have been > issues to devicetree's in both the kernel and u-boot to address > this issue. > > What really happened however, was that the AXP209 shuts down without > a notice and without setting an interrupt. This is caused when LDO3 > gets overloaded, for example with large capacitors on the LDO3 output. > > Normally, we would expect that AXP209 would source 200 mA as per > datasheet and set and trigger an interrupt when being overloaded. > For some reason however, this does not happen. > > As a work-around, we use the soft-start constraint of the regulator > node to first bring up the LDO3 to the lowest possible voltage and > then enable the LDO. After that, we can set the requested voltage > as usual. > > Combining this setting with the regulator-ramp-delay allows LDO3 to > enable voltage slowly and staggered, potentially reducing overall > inrush current. > > Signed-off-by: Olliver Schinagl <oliver@schinagl.nl> > Signed-off-by: Priit Laes <plaes@plaes.org> > --- > drivers/regulator/axp20x-regulator.c | 57 ++++++++++++++++++++++++++++- > 1 file changed, 56 insertions(+), 1 deletion(-) > > diff --git a/drivers/regulator/axp20x-regulator.c b/drivers/regulator/axp20x-regulator.c > index 1d9fa62..e8a895b 100644 > --- a/drivers/regulator/axp20x-regulator.c > +++ b/drivers/regulator/axp20x-regulator.c > @@ -14,6 +14,7 @@ > */ > > #include <linux/bitops.h> > +#include <linux/delay.h> > #include <linux/err.h> > #include <linux/init.h> > #include <linux/mfd/axp20x.h> > @@ -23,6 +24,7 @@ > #include <linux/platform_device.h> > #include <linux/regmap.h> > #include <linux/regulator/driver.h> > +#include <linux/regulator/machine.h> > #include <linux/regulator/of_regulator.h> > > #define AXP20X_GPIO0_FUNC_MASK GENMASK(3, 0) > @@ -430,6 +432,59 @@ static int axp20x_set_ramp_delay(struct regulator_dev *rdev, int ramp) > return regmap_update_bits(axp20x->regmap, reg, mask, cfg); > } > > +static int axp20x_regulator_enable_regmap(struct regulator_dev *rdev) > +{ > + struct axp20x_dev *axp20x = rdev_get_drvdata(rdev); > + const struct regulator_desc *desc = rdev->desc; > + > + if (!rdev) > + return -EINVAL; > + > + switch (axp20x->variant) { > + case AXP209_ID: > + if ((desc->id == AXP20X_LDO3) && > + rdev->constraints && rdev->constraints->soft_start) { > + int v_out; > + int ret; > + > + /* > + * On some boards, the LDO3 can be overloaded when > + * turning on, causing the entire PMIC to shutdown > + * without warning. Turning it on at the minimal voltage > + * and then setting the voltage to the requested value > + * works reliably. > + */ > + if (regulator_is_enabled_regmap(rdev)) > + break; > + > + v_out = regulator_get_voltage_sel_regmap(rdev); > + if (v_out < 0) > + return v_out; > + > + if (v_out == 0) > + break; > + > + ret = regulator_set_voltage_sel_regmap(rdev, 0x00); > + /* > + * A small pause is needed between > + * setting the voltage and enabling the LDO to give the > + * internal state machine time to process the request. > + */ > + usleep_range(1000, 5000); > + ret |= regulator_enable_regmap(rdev); > + ret |= regulator_set_voltage_sel_regmap(rdev, v_out); > + > + return ret; > + } > + break; > + default: > + /* No quirks */ > + break; > + } > + > + return regulator_enable_regmap(rdev); > +}; > + This is some pretty generic code, and could be useful to some other users. I guess a generic function would be better for this. Maxime
On Tue, Nov 27, 2018 at 10:36:19AM +0100, Maxime Ripard wrote: > On Mon, Nov 26, 2018 at 05:27:47PM +0200, Priit Laes wrote: > > From: Olliver Schinagl <oliver@schinagl.nl> > > > > In the past, there have been words on various lists that if LDO3 is > > disabled in u-boot, but enabled in the DTS, the axp209 driver would > > fail to continue/hang. Several enable/disable patches have been > > issues to devicetree's in both the kernel and u-boot to address > > this issue. > > > > What really happened however, was that the AXP209 shuts down without > > a notice and without setting an interrupt. This is caused when LDO3 > > gets overloaded, for example with large capacitors on the LDO3 output. > > > > Normally, we would expect that AXP209 would source 200 mA as per > > datasheet and set and trigger an interrupt when being overloaded. > > For some reason however, this does not happen. > > > > As a work-around, we use the soft-start constraint of the regulator > > node to first bring up the LDO3 to the lowest possible voltage and > > then enable the LDO. After that, we can set the requested voltage > > as usual. > > > > Combining this setting with the regulator-ramp-delay allows LDO3 to > > enable voltage slowly and staggered, potentially reducing overall > > inrush current. > > > > Signed-off-by: Olliver Schinagl <oliver@schinagl.nl> > > Signed-off-by: Priit Laes <plaes@plaes.org> > > --- > > drivers/regulator/axp20x-regulator.c | 57 ++++++++++++++++++++++++++++- > > 1 file changed, 56 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/regulator/axp20x-regulator.c b/drivers/regulator/axp20x-regulator.c > > index 1d9fa62..e8a895b 100644 > > --- a/drivers/regulator/axp20x-regulator.c > > +++ b/drivers/regulator/axp20x-regulator.c > > @@ -14,6 +14,7 @@ > > */ > > > > #include <linux/bitops.h> > > +#include <linux/delay.h> > > #include <linux/err.h> > > #include <linux/init.h> > > #include <linux/mfd/axp20x.h> > > @@ -23,6 +24,7 @@ > > #include <linux/platform_device.h> > > #include <linux/regmap.h> > > #include <linux/regulator/driver.h> > > +#include <linux/regulator/machine.h> > > #include <linux/regulator/of_regulator.h> > > > > #define AXP20X_GPIO0_FUNC_MASK GENMASK(3, 0) > > @@ -430,6 +432,59 @@ static int axp20x_set_ramp_delay(struct regulator_dev *rdev, int ramp) > > return regmap_update_bits(axp20x->regmap, reg, mask, cfg); > > } > > > > +static int axp20x_regulator_enable_regmap(struct regulator_dev *rdev) > > +{ > > + struct axp20x_dev *axp20x = rdev_get_drvdata(rdev); > > + const struct regulator_desc *desc = rdev->desc; > > + > > + if (!rdev) > > + return -EINVAL; > > + > > + switch (axp20x->variant) { > > + case AXP209_ID: > > + if ((desc->id == AXP20X_LDO3) && > > + rdev->constraints && rdev->constraints->soft_start) { > > + int v_out; > > + int ret; > > + > > + /* > > + * On some boards, the LDO3 can be overloaded when > > + * turning on, causing the entire PMIC to shutdown > > + * without warning. Turning it on at the minimal voltage > > + * and then setting the voltage to the requested value > > + * works reliably. > > + */ > > + if (regulator_is_enabled_regmap(rdev)) > > + break; > > + > > + v_out = regulator_get_voltage_sel_regmap(rdev); > > + if (v_out < 0) > > + return v_out; > > + > > + if (v_out == 0) > > + break; > > + > > + ret = regulator_set_voltage_sel_regmap(rdev, 0x00); > > + /* > > + * A small pause is needed between > > + * setting the voltage and enabling the LDO to give the > > + * internal state machine time to process the request. > > + */ > > + usleep_range(1000, 5000); > > + ret |= regulator_enable_regmap(rdev); > > + ret |= regulator_set_voltage_sel_regmap(rdev, v_out); > > + > > + return ret; > > + } > > + break; > > + default: > > + /* No quirks */ > > + break; > > + } > > + > > + return regulator_enable_regmap(rdev); > > +}; > > + > > This is some pretty generic code, and could be useful to some other > users. I guess a generic function would be better for this. Yes, makes sense. Although, should we then also distinguish between regulators which support soft-start in hardware and devices which emulate it by delay, like in this case? Päikest, Priit
On Tue, Dec 04, 2018 at 01:31:44PM +0000, Priit Laes wrote: > Yes, makes sense. Although, should we then also distinguish between > regulators which support soft-start in hardware and devices which emulate > it by delay, like in this case? Drivers should not be emulating soft start, if they need a ramp delay they should set that in their descriptor and let the framework do it.
diff --git a/drivers/regulator/axp20x-regulator.c b/drivers/regulator/axp20x-regulator.c index 1d9fa62..e8a895b 100644 --- a/drivers/regulator/axp20x-regulator.c +++ b/drivers/regulator/axp20x-regulator.c @@ -14,6 +14,7 @@ */ #include <linux/bitops.h> +#include <linux/delay.h> #include <linux/err.h> #include <linux/init.h> #include <linux/mfd/axp20x.h> @@ -23,6 +24,7 @@ #include <linux/platform_device.h> #include <linux/regmap.h> #include <linux/regulator/driver.h> +#include <linux/regulator/machine.h> #include <linux/regulator/of_regulator.h> #define AXP20X_GPIO0_FUNC_MASK GENMASK(3, 0) @@ -430,6 +432,59 @@ static int axp20x_set_ramp_delay(struct regulator_dev *rdev, int ramp) return regmap_update_bits(axp20x->regmap, reg, mask, cfg); } +static int axp20x_regulator_enable_regmap(struct regulator_dev *rdev) +{ + struct axp20x_dev *axp20x = rdev_get_drvdata(rdev); + const struct regulator_desc *desc = rdev->desc; + + if (!rdev) + return -EINVAL; + + switch (axp20x->variant) { + case AXP209_ID: + if ((desc->id == AXP20X_LDO3) && + rdev->constraints && rdev->constraints->soft_start) { + int v_out; + int ret; + + /* + * On some boards, the LDO3 can be overloaded when + * turning on, causing the entire PMIC to shutdown + * without warning. Turning it on at the minimal voltage + * and then setting the voltage to the requested value + * works reliably. + */ + if (regulator_is_enabled_regmap(rdev)) + break; + + v_out = regulator_get_voltage_sel_regmap(rdev); + if (v_out < 0) + return v_out; + + if (v_out == 0) + break; + + ret = regulator_set_voltage_sel_regmap(rdev, 0x00); + /* + * A small pause is needed between + * setting the voltage and enabling the LDO to give the + * internal state machine time to process the request. + */ + usleep_range(1000, 5000); + ret |= regulator_enable_regmap(rdev); + ret |= regulator_set_voltage_sel_regmap(rdev, v_out); + + return ret; + } + break; + default: + /* No quirks */ + break; + } + + return regulator_enable_regmap(rdev); +}; + static const struct regulator_ops axp20x_ops_fixed = { .list_voltage = regulator_list_voltage_linear, }; @@ -447,7 +502,7 @@ static const struct regulator_ops axp20x_ops = { .set_voltage_sel = regulator_set_voltage_sel_regmap, .get_voltage_sel = regulator_get_voltage_sel_regmap, .list_voltage = regulator_list_voltage_linear, - .enable = regulator_enable_regmap, + .enable = axp20x_regulator_enable_regmap, .disable = regulator_disable_regmap, .is_enabled = regulator_is_enabled_regmap, .set_ramp_delay = axp20x_set_ramp_delay,