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Subject[PATCH 4.9 006/191] backlight: lp855x: Ensure regulators are disabled on probe failure
Date
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 939f057836e19..4cdc7a3f6dc5c 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);
--
2.25.1
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