| From cca56efcfb39f268f660844c1d229a081878b299 Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Thu, 16 Jan 2020 10:45:43 +0100 |
| Subject: regulator: vctrl-regulator: Avoid deadlock getting and setting the |
| voltage |
| |
| From: Enric Balletbo i Serra <enric.balletbo@collabora.com> |
| |
| [ Upstream commit e9153311491da9d9863ead9888a1613531cb4a1b ] |
| |
| `cat /sys/kernel/debug/regulator/regulator_summary` ends on a deadlock |
| when you have a voltage controlled regulator (vctrl). |
| |
| The problem is that the vctrl_get_voltage() and vctrl_set_voltage() calls the |
| regulator_get_voltage() and regulator_set_voltage() and that will try to lock |
| again the dependent regulators (the regulator supplying the control voltage). |
| |
| Fix the issue by exporting the unlocked version of the regulator_get_voltage() |
| and regulator_set_voltage() API so drivers that need it, like the voltage |
| controlled regulator driver can use it. |
| |
| Fixes: f8702f9e4aa7 ("regulator: core: Use ww_mutex for regulators locking") |
| Reported-by: Douglas Anderson <dianders@chromium.org> |
| Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com> |
| Link: https://lore.kernel.org/r/20200116094543.2847321-1-enric.balletbo@collabora.com |
| Signed-off-by: Mark Brown <broonie@kernel.org> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| drivers/regulator/core.c | 2 ++ |
| drivers/regulator/vctrl-regulator.c | 38 +++++++++++++++++------------ |
| 2 files changed, 25 insertions(+), 15 deletions(-) |
| |
| diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c |
| index 1dba0bdf37623..c6fa0f4451aeb 100644 |
| --- a/drivers/regulator/core.c |
| +++ b/drivers/regulator/core.c |
| @@ -3462,6 +3462,7 @@ int regulator_set_voltage_rdev(struct regulator_dev *rdev, int min_uV, |
| out: |
| return ret; |
| } |
| +EXPORT_SYMBOL(regulator_set_voltage_rdev); |
| |
| static int regulator_limit_voltage_step(struct regulator_dev *rdev, |
| int *current_uV, int *min_uV) |
| @@ -4026,6 +4027,7 @@ int regulator_get_voltage_rdev(struct regulator_dev *rdev) |
| return ret; |
| return ret - rdev->constraints->uV_offset; |
| } |
| +EXPORT_SYMBOL(regulator_get_voltage_rdev); |
| |
| /** |
| * regulator_get_voltage - get regulator output voltage |
| diff --git a/drivers/regulator/vctrl-regulator.c b/drivers/regulator/vctrl-regulator.c |
| index 9a9ee81881098..cbadb1c996790 100644 |
| --- a/drivers/regulator/vctrl-regulator.c |
| +++ b/drivers/regulator/vctrl-regulator.c |
| @@ -11,10 +11,13 @@ |
| #include <linux/module.h> |
| #include <linux/of.h> |
| #include <linux/of_device.h> |
| +#include <linux/regulator/coupler.h> |
| #include <linux/regulator/driver.h> |
| #include <linux/regulator/of_regulator.h> |
| #include <linux/sort.h> |
| |
| +#include "internal.h" |
| + |
| struct vctrl_voltage_range { |
| int min_uV; |
| int max_uV; |
| @@ -79,7 +82,7 @@ static int vctrl_calc_output_voltage(struct vctrl_data *vctrl, int ctrl_uV) |
| static int vctrl_get_voltage(struct regulator_dev *rdev) |
| { |
| struct vctrl_data *vctrl = rdev_get_drvdata(rdev); |
| - int ctrl_uV = regulator_get_voltage(vctrl->ctrl_reg); |
| + int ctrl_uV = regulator_get_voltage_rdev(vctrl->ctrl_reg->rdev); |
| |
| return vctrl_calc_output_voltage(vctrl, ctrl_uV); |
| } |
| @@ -90,16 +93,16 @@ static int vctrl_set_voltage(struct regulator_dev *rdev, |
| { |
| struct vctrl_data *vctrl = rdev_get_drvdata(rdev); |
| struct regulator *ctrl_reg = vctrl->ctrl_reg; |
| - int orig_ctrl_uV = regulator_get_voltage(ctrl_reg); |
| + int orig_ctrl_uV = regulator_get_voltage_rdev(ctrl_reg->rdev); |
| int uV = vctrl_calc_output_voltage(vctrl, orig_ctrl_uV); |
| int ret; |
| |
| if (req_min_uV >= uV || !vctrl->ovp_threshold) |
| /* voltage rising or no OVP */ |
| - return regulator_set_voltage( |
| - ctrl_reg, |
| + return regulator_set_voltage_rdev(ctrl_reg->rdev, |
| vctrl_calc_ctrl_voltage(vctrl, req_min_uV), |
| - vctrl_calc_ctrl_voltage(vctrl, req_max_uV)); |
| + vctrl_calc_ctrl_voltage(vctrl, req_max_uV), |
| + PM_SUSPEND_ON); |
| |
| while (uV > req_min_uV) { |
| int max_drop_uV = (uV * vctrl->ovp_threshold) / 100; |
| @@ -114,9 +117,10 @@ static int vctrl_set_voltage(struct regulator_dev *rdev, |
| next_uV = max_t(int, req_min_uV, uV - max_drop_uV); |
| next_ctrl_uV = vctrl_calc_ctrl_voltage(vctrl, next_uV); |
| |
| - ret = regulator_set_voltage(ctrl_reg, |
| + ret = regulator_set_voltage_rdev(ctrl_reg->rdev, |
| + next_ctrl_uV, |
| next_ctrl_uV, |
| - next_ctrl_uV); |
| + PM_SUSPEND_ON); |
| if (ret) |
| goto err; |
| |
| @@ -130,7 +134,8 @@ static int vctrl_set_voltage(struct regulator_dev *rdev, |
| |
| err: |
| /* Try to go back to original voltage */ |
| - regulator_set_voltage(ctrl_reg, orig_ctrl_uV, orig_ctrl_uV); |
| + regulator_set_voltage_rdev(ctrl_reg->rdev, orig_ctrl_uV, orig_ctrl_uV, |
| + PM_SUSPEND_ON); |
| |
| return ret; |
| } |
| @@ -155,9 +160,10 @@ static int vctrl_set_voltage_sel(struct regulator_dev *rdev, |
| |
| if (selector >= vctrl->sel || !vctrl->ovp_threshold) { |
| /* voltage rising or no OVP */ |
| - ret = regulator_set_voltage(ctrl_reg, |
| + ret = regulator_set_voltage_rdev(ctrl_reg->rdev, |
| + vctrl->vtable[selector].ctrl, |
| vctrl->vtable[selector].ctrl, |
| - vctrl->vtable[selector].ctrl); |
| + PM_SUSPEND_ON); |
| if (!ret) |
| vctrl->sel = selector; |
| |
| @@ -173,9 +179,10 @@ static int vctrl_set_voltage_sel(struct regulator_dev *rdev, |
| else |
| next_sel = vctrl->vtable[vctrl->sel].ovp_min_sel; |
| |
| - ret = regulator_set_voltage(ctrl_reg, |
| + ret = regulator_set_voltage_rdev(ctrl_reg->rdev, |
| vctrl->vtable[next_sel].ctrl, |
| - vctrl->vtable[next_sel].ctrl); |
| + vctrl->vtable[next_sel].ctrl, |
| + PM_SUSPEND_ON); |
| if (ret) { |
| dev_err(&rdev->dev, |
| "failed to set control voltage to %duV\n", |
| @@ -195,9 +202,10 @@ static int vctrl_set_voltage_sel(struct regulator_dev *rdev, |
| err: |
| if (vctrl->sel != orig_sel) { |
| /* Try to go back to original voltage */ |
| - if (!regulator_set_voltage(ctrl_reg, |
| + if (!regulator_set_voltage_rdev(ctrl_reg->rdev, |
| + vctrl->vtable[orig_sel].ctrl, |
| vctrl->vtable[orig_sel].ctrl, |
| - vctrl->vtable[orig_sel].ctrl)) |
| + PM_SUSPEND_ON)) |
| vctrl->sel = orig_sel; |
| else |
| dev_warn(&rdev->dev, |
| @@ -482,7 +490,7 @@ static int vctrl_probe(struct platform_device *pdev) |
| if (ret) |
| return ret; |
| |
| - ctrl_uV = regulator_get_voltage(vctrl->ctrl_reg); |
| + ctrl_uV = regulator_get_voltage_rdev(vctrl->ctrl_reg->rdev); |
| if (ctrl_uV < 0) { |
| dev_err(&pdev->dev, "failed to get control voltage\n"); |
| return ctrl_uV; |
| -- |
| 2.20.1 |
| |