Messages in this thread Patch in this message | | | From | Mark Brown <> | Subject | Applied "regulator: axp20x: add software based soft_start for AXP209 LDO3" to the regulator tree | Date | Thu, 13 Dec 2018 18:11:39 +0000 (GMT) |
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The patch
regulator: axp20x: add software based soft_start for AXP209 LDO3
has been applied to the regulator tree at
https://git.kernel.org/pub/scm/linux/kernel/git/broonie/regulator.git
All being well this means that it will be integrated into the linux-next tree (usually sometime in the next 24 hours) and sent to Linus during the next merge window (or sooner if it is a bug fix), however if problems are discovered then the patch may be dropped or reverted.
You may get further e-mails resulting from automated or manual testing and review of the tree, please engage with people reporting problems and send followup patches addressing any issues that are reported if needed.
If any updates are required or you are submitting further changes they should be sent as incremental updates against current git, existing patches will not be replaced.
Please add any relevant lists and maintainers to the CCs when replying to this mail.
Thanks, Mark
From 77e3e3b165db94dc48c0de30498f51fa38f19d4d Mon Sep 17 00:00:00 2001 From: Olliver Schinagl <oliver@schinagl.nl> Date: Tue, 11 Dec 2018 17:17:08 +0200 Subject: [PATCH] regulator: axp20x: add software based soft_start for AXP209 LDO3
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> Signed-off-by: Mark Brown <broonie@kernel.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 1d9fa6238aec..e8a895b81c90 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, -- 2.19.0.rc2
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