From: Jon Hunter jonathanh@nvidia.com

[ Upstream commit d8207c155a7c6015eb7f43739baa7dfb1fa638af ]

If probing the LP885x backlight fails after the regulators have been enabled, then the following warning is seen when releasing the regulators ...

WARNING: CPU: 1 PID: 289 at drivers/regulator/core.c:2051 _regulator_put.part.28+0x158/0x160 Modules linked in: tegra_xudc lp855x_bl(+) host1x pwm_tegra ip_tables x_tables ipv6 nf_defrag_ipv6 CPU: 1 PID: 289 Comm: systemd-udevd Not tainted 5.6.0-rc2-next-20200224 #1 Hardware name: NVIDIA Jetson TX1 Developer Kit (DT)

...

Call trace: _regulator_put.part.28+0x158/0x160 regulator_put+0x34/0x50 devm_regulator_release+0x10/0x18 release_nodes+0x12c/0x230 devres_release_all+0x34/0x50 really_probe+0x1c0/0x370 driver_probe_device+0x58/0x100 device_driver_attach+0x6c/0x78 __driver_attach+0xb0/0xf0 bus_for_each_dev+0x68/0xc8 driver_attach+0x20/0x28 bus_add_driver+0x160/0x1f0 driver_register+0x60/0x110 i2c_register_driver+0x40/0x80 lp855x_driver_init+0x20/0x1000 [lp855x_bl] do_one_initcall+0x58/0x1a0 do_init_module+0x54/0x1d0 load_module+0x1d80/0x21c8 __do_sys_finit_module+0xe8/0x100 __arm64_sys_finit_module+0x18/0x20 el0_svc_common.constprop.3+0xb0/0x168 do_el0_svc+0x20/0x98 el0_sync_handler+0xf4/0x1b0 el0_sync+0x140/0x180

Fix this by ensuring that the regulators are disabled, if enabled, on probe failure.

Finally, ensure that the vddio regulator is disabled in the driver remove handler.

Signed-off-by: Jon Hunter jonathanh@nvidia.com Reviewed-by: Daniel Thompson daniel.thompson@linaro.org Signed-off-by: Lee Jones lee.jones@linaro.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/video/backlight/lp855x_bl.c | 20 ++++++++++++++++---- 1 file changed, 16 insertions(+), 4 deletions(-)

diff --git a/drivers/video/backlight/lp855x_bl.c b/drivers/video/backlight/lp855x_bl.c index 939f057836e1..4cdc7a3f6dc5 100644 --- a/drivers/video/backlight/lp855x_bl.c +++ b/drivers/video/backlight/lp855x_bl.c @@ -460,7 +460,7 @@ static int lp855x_probe(struct i2c_client *cl, const struct i2c_device_id *id) ret = regulator_enable(lp->enable); if (ret < 0) { dev_err(lp->dev, "failed to enable vddio: %d\n", ret); - return ret; + goto disable_supply; }

/* @@ -475,24 +475,34 @@ static int lp855x_probe(struct i2c_client *cl, const struct i2c_device_id *id) ret = lp855x_configure(lp); if (ret) { dev_err(lp->dev, "device config err: %d", ret); - return ret; + goto disable_vddio; }

ret = lp855x_backlight_register(lp); if (ret) { dev_err(lp->dev, "failed to register backlight. err: %d\n", ret); - return ret; + goto disable_vddio; }

ret = sysfs_create_group(&lp->dev->kobj, &lp855x_attr_group); if (ret) { dev_err(lp->dev, "failed to register sysfs. err: %d\n", ret); - return ret; + goto disable_vddio; }

backlight_update_status(lp->bl); + return 0; + +disable_vddio: + if (lp->enable) + regulator_disable(lp->enable); +disable_supply: + if (lp->supply) + regulator_disable(lp->supply); + + return ret; }

static int lp855x_remove(struct i2c_client *cl) @@ -501,6 +511,8 @@ static int lp855x_remove(struct i2c_client *cl)

lp->bl->props.brightness = 0; backlight_update_status(lp->bl); + if (lp->enable) + regulator_disable(lp->enable); if (lp->supply) regulator_disable(lp->supply); sysfs_remove_group(&lp->dev->kobj, &lp855x_attr_group);