From 0187294d227dfc42889e1da8f8ce1e44fc25f147 Mon Sep 17 00:00:00 2001
From: Dinghao Liu <dinghao.liu@zju.edu.cn>
Date: Tue, 26 May 2020 18:47:17 +0800
Subject: [PATCH] iio: magnetometer: ak8974: Fix runtime PM imbalance on error
Git-commit: 0187294d227dfc42889e1da8f8ce1e44fc25f147
Patch-mainline: v5.8-rc6
References: git-fixes

When devm_regmap_init_i2c() returns an error code, a pairing
runtime PM usage counter decrement is needed to keep the
counter balanced. For error paths after ak8974_set_power(),
ak8974_detect() and ak8974_reset(), things are the same.

However, When iio_triggered_buffer_setup() returns an error
code, there will be two PM usgae counter decrements.

Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn>
Fixes: 7c94a8b2ee8c ("iio: magn: add a driver for AK8974")
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/iio/magnetometer/ak8974.c |   19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

--- a/drivers/iio/magnetometer/ak8974.c
+++ b/drivers/iio/magnetometer/ak8974.c
@@ -764,19 +764,21 @@ static int ak8974_probe(struct i2c_clien
 	ak8974->map = devm_regmap_init_i2c(i2c, &ak8974_regmap_config);
 	if (IS_ERR(ak8974->map)) {
 		dev_err(&i2c->dev, "failed to allocate register map\n");
+		pm_runtime_put_noidle(&i2c->dev);
+		pm_runtime_disable(&i2c->dev);
 		return PTR_ERR(ak8974->map);
 	}
 
 	ret = ak8974_set_power(ak8974, AK8974_PWR_ON);
 	if (ret) {
 		dev_err(&i2c->dev, "could not power on\n");
-		goto power_off;
+		goto disable_pm;
 	}
 
 	ret = ak8974_detect(ak8974);
 	if (ret) {
 		dev_err(&i2c->dev, "neither AK8974 nor AMI30x found\n");
-		goto power_off;
+		goto disable_pm;
 	}
 
 	ret = ak8974_selftest(ak8974);
@@ -786,14 +788,9 @@ static int ak8974_probe(struct i2c_clien
 	ret = ak8974_reset(ak8974);
 	if (ret) {
 		dev_err(&i2c->dev, "AK8974 reset failed\n");
-		goto power_off;
+		goto disable_pm;
 	}
 
-	pm_runtime_set_autosuspend_delay(&i2c->dev,
-					 AK8974_AUTOSUSPEND_DELAY);
-	pm_runtime_use_autosuspend(&i2c->dev);
-	pm_runtime_put(&i2c->dev);
-
 	indio_dev->dev.parent = &i2c->dev;
 	indio_dev->channels = ak8974_channels;
 	indio_dev->num_channels = ARRAY_SIZE(ak8974_channels);
@@ -846,6 +843,11 @@ no_irq:
 		goto cleanup_buffer;
 	}
 
+	pm_runtime_set_autosuspend_delay(&i2c->dev,
+					 AK8974_AUTOSUSPEND_DELAY);
+	pm_runtime_use_autosuspend(&i2c->dev);
+	pm_runtime_put(&i2c->dev);
+
 	return 0;
 
 cleanup_buffer:
@@ -854,7 +856,6 @@ disable_pm:
 	pm_runtime_put_noidle(&i2c->dev);
 	pm_runtime_disable(&i2c->dev);
 	ak8974_set_power(ak8974, AK8974_PWR_OFF);
-power_off:
 	regulator_bulk_disable(ARRAY_SIZE(ak8974->regs), ak8974->regs);
 
 	return ret;