[PATCH v2 3/8] i2c-mux: move the slave side adapter management to i2c_mux_core

[Peter Rosin <peda@lysator.liu.se>]

From: Peter Rosin <peda@axentia.se>

All muxes have slave side adapters, many have some arbitrary number of
them. Handle this in the mux core, so that drivers are simplified.

Add i2c_mux_reserve_adapter that can be used when it is known in advance
how many child adapters that is to be added. This avoids reallocating
memory.

Drop i2c_del_mux_adapter and replace it with i2c_del_mux_adapters, since
no mux driver is dynamically deleting individual child adapters anyway.

Signed-off-by: Peter Rosin <peda@axentia.se>
---
 drivers/i2c/i2c-mux.c                        | 71 ++++++++++++++++++++++------
 drivers/i2c/muxes/i2c-arb-gpio-challenge.c   | 10 ++--
 drivers/i2c/muxes/i2c-mux-gpio.c             | 23 +++------
 drivers/i2c/muxes/i2c-mux-pca9541.c          | 13 ++---
 drivers/i2c/muxes/i2c-mux-pca954x.c          | 26 ++++------
 drivers/i2c/muxes/i2c-mux-pinctrl.c          | 27 +++--------
 drivers/i2c/muxes/i2c-mux-reg.c              | 28 ++++-------
 drivers/iio/imu/inv_mpu6050/inv_mpu_core.c   | 12 ++---
 drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h    |  1 -
 drivers/media/dvb-frontends/m88ds3103.c      | 11 ++---
 drivers/media/dvb-frontends/m88ds3103_priv.h |  1 -
 drivers/media/dvb-frontends/rtl2830.c        | 10 ++--
 drivers/media/dvb-frontends/rtl2830_priv.h   |  1 -
 drivers/media/dvb-frontends/rtl2832.c        | 11 ++---
 drivers/media/dvb-frontends/rtl2832_priv.h   |  1 -
 drivers/media/dvb-frontends/si2168.c         | 10 ++--
 drivers/media/dvb-frontends/si2168_priv.h    |  1 -
 drivers/media/usb/cx231xx/cx231xx-core.c     |  3 +-
 drivers/media/usb/cx231xx/cx231xx-i2c.c      | 26 +++++-----
 drivers/media/usb/cx231xx/cx231xx.h          |  2 +-
 drivers/of/unittest.c                        | 28 ++++-------
 include/linux/i2c-mux.h                      | 15 ++++--
 22 files changed, 149 insertions(+), 182 deletions(-)

diff --git a/drivers/i2c/i2c-mux.c b/drivers/i2c/i2c-mux.c
index 6c5cb9f7649b..7ba0308537a8 100644
--- a/drivers/i2c/i2c-mux.c
+++ b/drivers/i2c/i2c-mux.c
@@ -99,6 +99,29 @@ static unsigned int i2c_mux_parent_classes(struct i2c_adapter *parent)
 	return class;
 }
 
+int i2c_mux_reserve_adapters(struct i2c_mux_core *muxc, int adapters)
+{
+	struct i2c_adapter **adapter;
+
+	if (adapters <= muxc->max_adapters)
+		return 0;
+
+	adapter = devm_kmalloc_array(muxc->dev,
+				     adapters, sizeof(*adapter),
+				     GFP_KERNEL);
+	if (!adapter)
+		return -ENOMEM;
+
+	memcpy(adapter, muxc->adapter,
+	       muxc->max_adapters * sizeof(*adapter));
+
+	devm_kfree(muxc->dev, muxc->adapter);
+	muxc->adapter = adapter;
+	muxc->max_adapters = adapters;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(i2c_mux_reserve_adapters);
+
 struct i2c_mux_core *i2c_mux_alloc(struct device *dev, int sizeof_priv)
 {
 	struct i2c_mux_core *muxc;
@@ -113,19 +136,29 @@ struct i2c_mux_core *i2c_mux_alloc(struct device *dev, int sizeof_priv)
 }
 EXPORT_SYMBOL_GPL(i2c_mux_alloc);
 
-struct i2c_adapter *i2c_add_mux_adapter(struct i2c_mux_core *muxc,
-					struct device *mux_dev,
-					u32 force_nr, u32 chan_id,
-					unsigned int class)
+int i2c_add_mux_adapter(struct i2c_mux_core *muxc,
+			struct device *mux_dev,
+			u32 force_nr, u32 chan_id,
+			unsigned int class)
 {
 	struct i2c_adapter *parent = muxc->parent;
 	struct i2c_mux_priv *priv;
 	char symlink_name[20];
 	int ret;
 
+	if (muxc->adapters >= muxc->max_adapters) {
+		int new_max = 2 * muxc->max_adapters;
+
+		if (!new_max)
+			new_max = 1;
+		ret = i2c_mux_reserve_adapters(muxc, new_max);
+		if (ret)
+			return ret;
+	}
+
 	priv = kzalloc(sizeof(struct i2c_mux_priv), GFP_KERNEL);
 	if (!priv)
-		return NULL;
+		return -ENOMEM;
 
 	/* Set up private adapter data */
 	priv->muxc = muxc;
@@ -197,7 +230,7 @@ struct i2c_adapter *i2c_add_mux_adapter(struct i2c_mux_core *muxc,
 			"failed to add mux-adapter (error=%d)\n",
 			ret);
 		kfree(priv);
-		return NULL;
+		return ret;
 	}
 
 	WARN(sysfs_create_link(&priv->adap.dev.kobj, &mux_dev->kobj, "mux_device"),
@@ -209,23 +242,31 @@ struct i2c_adapter *i2c_add_mux_adapter(struct i2c_mux_core *muxc,
 	dev_info(&parent->dev, "Added multiplexed i2c bus %d\n",
 		 i2c_adapter_id(&priv->adap));
 
-	return &priv->adap;
+	muxc->adapter[muxc->adapters++] = &priv->adap;
+	return 0;
 }
 EXPORT_SYMBOL_GPL(i2c_add_mux_adapter);
 
-void i2c_del_mux_adapter(struct i2c_adapter *adap)
+void i2c_del_mux_adapters(struct i2c_mux_core *muxc)
 {
-	struct i2c_mux_priv *priv = adap->algo_data;
 	char symlink_name[20];
 
-	snprintf(symlink_name, sizeof(symlink_name), "channel-%u", priv->chan_id);
-	sysfs_remove_link(&priv->mux_dev->kobj, symlink_name);
+	while (muxc->adapters) {
+		struct i2c_adapter *adap = muxc->adapter[--muxc->adapters];
+		struct i2c_mux_priv *priv = adap->algo_data;
 
-	sysfs_remove_link(&priv->adap.dev.kobj, "mux_device");
-	i2c_del_adapter(adap);
-	kfree(priv);
+		muxc->adapter[muxc->adapters] = NULL;
+
+		snprintf(symlink_name, sizeof(symlink_name),
+			 "channel-%u", priv->chan_id);
+		sysfs_remove_link(&priv->mux_dev->kobj, symlink_name);
+
+		sysfs_remove_link(&priv->adap.dev.kobj, "mux_device");
+		i2c_del_adapter(adap);
+		kfree(priv);
+	}
 }
-EXPORT_SYMBOL_GPL(i2c_del_mux_adapter);
+EXPORT_SYMBOL_GPL(i2c_del_mux_adapters);
 
 MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
 MODULE_DESCRIPTION("I2C driver for multiplexed I2C busses");
diff --git a/drivers/i2c/muxes/i2c-arb-gpio-challenge.c b/drivers/i2c/muxes/i2c-arb-gpio-challenge.c
index 1e1a479d5b61..e0558e8a0e74 100644
--- a/drivers/i2c/muxes/i2c-arb-gpio-challenge.c
+++ b/drivers/i2c/muxes/i2c-arb-gpio-challenge.c
@@ -42,7 +42,6 @@
  */
 
 struct i2c_arbitrator_data {
-	struct i2c_adapter *child;
 	int our_gpio;
 	int our_gpio_release;
 	int their_gpio;
@@ -205,10 +204,9 @@ static int i2c_arbitrator_probe(struct platform_device *pdev)
 	}
 
 	/* Actually add the mux adapter */
-	arb->child = i2c_add_mux_adapter(muxc, dev, 0, 0, 0);
-	if (!arb->child) {
+	ret = i2c_add_mux_adapter(muxc, dev, 0, 0, 0);
+	if (ret) {
 		dev_err(dev, "Failed to add adapter\n");
-		ret = -ENODEV;
 		i2c_put_adapter(muxc->parent);
 	}
 
@@ -218,11 +216,9 @@ static int i2c_arbitrator_probe(struct platform_device *pdev)
 static int i2c_arbitrator_remove(struct platform_device *pdev)
 {
 	struct i2c_mux_core *muxc = platform_get_drvdata(pdev);
-	struct i2c_arbitrator_data *arb = i2c_mux_priv(muxc);
 
-	i2c_del_mux_adapter(arb->child);
+	i2c_del_mux_adapters(muxc);
 	i2c_put_adapter(muxc->parent);
-
 	return 0;
 }
 
diff --git a/drivers/i2c/muxes/i2c-mux-gpio.c b/drivers/i2c/muxes/i2c-mux-gpio.c
index d89a0fbca4bc..6bd41ace81d4 100644
--- a/drivers/i2c/muxes/i2c-mux-gpio.c
+++ b/drivers/i2c/muxes/i2c-mux-gpio.c
@@ -18,7 +18,6 @@
 #include <linux/of_gpio.h>
 
 struct gpiomux {
-	struct i2c_adapter **adap; /* child busses */
 	struct i2c_mux_gpio_platform_data data;
 	unsigned gpio_base;
 };
@@ -182,14 +181,9 @@ static int i2c_mux_gpio_probe(struct platform_device *pdev)
 	muxc->select = i2c_mux_gpio_select;
 	mux->gpio_base = gpio_base;
 
-	mux->adap = devm_kzalloc(&pdev->dev,
-				 sizeof(*mux->adap) * mux->data.n_values,
-				 GFP_KERNEL);
-	if (!mux->adap) {
-		dev_err(&pdev->dev, "Cannot allocate i2c_adapter structure");
-		ret = -ENOMEM;
+	ret = i2c_mux_reserve_adapters(muxc, mux->data.n_values);
+	if (ret)
 		goto alloc_failed;
-	}
 
 	if (mux->data.idle != I2C_MUX_GPIO_NO_IDLE) {
 		initial_state = mux->data.idle;
@@ -222,10 +216,9 @@ static int i2c_mux_gpio_probe(struct platform_device *pdev)
 		u32 nr = mux->data.base_nr ? (mux->data.base_nr + i) : 0;
 		unsigned int class = mux->data.classes ? mux->data.classes[i] : 0;
 
-		mux->adap[i] = i2c_add_mux_adapter(muxc, &pdev->dev, nr,
-						   mux->data.values[i], class);
-		if (!mux->adap[i]) {
-			ret = -ENODEV;
+		ret = i2c_add_mux_adapter(muxc, &pdev->dev, nr,
+					  mux->data.values[i], class);
+		if (ret) {
 			dev_err(&pdev->dev, "Failed to add adapter %d\n", i);
 			goto add_adapter_failed;
 		}
@@ -237,8 +230,7 @@ static int i2c_mux_gpio_probe(struct platform_device *pdev)
 	return 0;
 
 add_adapter_failed:
-	for (; i > 0; i--)
-		i2c_del_mux_adapter(mux->adap[i - 1]);
+	i2c_del_mux_adapters(muxc);
 	i = mux->data.n_gpios;
 err_request_gpio:
 	for (; i > 0; i--)
@@ -255,8 +247,7 @@ static int i2c_mux_gpio_remove(struct platform_device *pdev)
 	struct gpiomux *mux = i2c_mux_priv(muxc);
 	int i;
 
-	for (i = 0; i < mux->data.n_values; i++)
-		i2c_del_mux_adapter(mux->adap[i]);
+	i2c_del_mux_adapters(muxc);
 
 	for (i = 0; i < mux->data.n_gpios; i++)
 		gpio_free(mux->gpio_base + mux->data.gpios[i]);
diff --git a/drivers/i2c/muxes/i2c-mux-pca9541.c b/drivers/i2c/muxes/i2c-mux-pca9541.c
index ae42039459d0..80de0a0977a5 100644
--- a/drivers/i2c/muxes/i2c-mux-pca9541.c
+++ b/drivers/i2c/muxes/i2c-mux-pca9541.c
@@ -74,7 +74,6 @@
 
 struct pca9541 {
 	struct i2c_client *client;
-	struct i2c_adapter *mux_adap;
 	unsigned long select_timeout;
 	unsigned long arb_timeout;
 };
@@ -332,6 +331,7 @@ static int pca9541_probe(struct i2c_client *client,
 	struct i2c_mux_core *muxc;
 	struct pca9541 *data;
 	int force;
+	int ret;
 
 	if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_BYTE_DATA))
 		return -ENODEV;
@@ -361,11 +361,10 @@ static int pca9541_probe(struct i2c_client *client,
 	force = 0;
 	if (pdata)
 		force = pdata->modes[0].adap_id;
-	data->mux_adap = i2c_add_mux_adapter(muxc, &client->dev, force, 0, 0);
-
-	if (data->mux_adap == NULL) {
+	ret = i2c_add_mux_adapter(muxc, &client->dev, force, 0, 0);
+	if (ret) {
 		dev_err(&client->dev, "failed to register master selector\n");
-		return -ENODEV;
+		return ret;
 	}
 
 	dev_info(&client->dev, "registered master selector for I2C %s\n",
@@ -377,10 +376,8 @@ static int pca9541_probe(struct i2c_client *client,
 static int pca9541_remove(struct i2c_client *client)
 {
 	struct i2c_mux_core *muxc = i2c_get_clientdata(client);
-	struct pca9541 *data = i2c_mux_priv(muxc);
-
-	i2c_del_mux_adapter(data->mux_adap);
 
+	i2c_del_mux_adapters(muxc);
 	return 0;
 }
 
diff --git a/drivers/i2c/muxes/i2c-mux-pca954x.c b/drivers/i2c/muxes/i2c-mux-pca954x.c
index 9e9d708fb2cb..640670b604f5 100644
--- a/drivers/i2c/muxes/i2c-mux-pca954x.c
+++ b/drivers/i2c/muxes/i2c-mux-pca954x.c
@@ -60,7 +60,6 @@ enum pca_type {
 
 struct pca954x {
 	enum pca_type type;
-	struct i2c_adapter *virt_adaps[PCA954X_MAX_NCHANS];
 
 	u8 last_chan;		/* last register value */
 	u8 deselect;
@@ -231,6 +230,10 @@ static int pca954x_probe(struct i2c_client *client,
 	data->type = id->driver_data;
 	data->last_chan = 0;		   /* force the first selection */
 
+	ret = i2c_mux_reserve_adapters(muxc, chips[data->type].nchans);
+	if (ret)
+		return ret;
+
 	idle_disconnect_dt = of_node &&
 		of_property_read_bool(of_node, "i2c-mux-idle-disconnect");
 
@@ -253,12 +256,10 @@ static int pca954x_probe(struct i2c_client *client,
 					   || idle_disconnect_dt) << num;
 		}
 
-		data->virt_adaps[num] =
-			i2c_add_mux_adapter(muxc, &client->dev,
-					    force, num, class);
+		ret = i2c_add_mux_adapter(muxc, &client->dev,
+					  force, num, class);
 
-		if (data->virt_adaps[num] == NULL) {
-			ret = -ENODEV;
+		if (ret) {
 			dev_err(&client->dev,
 				"failed to register multiplexed adapter"
 				" %d as bus %d\n", num, force);
@@ -274,24 +275,15 @@ static int pca954x_probe(struct i2c_client *client,
 	return 0;
 
 virt_reg_failed:
-	for (num--; num >= 0; num--)
-		i2c_del_mux_adapter(data->virt_adaps[num]);
+	i2c_del_mux_adapters(muxc);
 	return ret;
 }
 
 static int pca954x_remove(struct i2c_client *client)
 {
 	struct i2c_mux_core *muxc = i2c_get_clientdata(client);
-	struct pca954x *data = i2c_mux_priv(muxc);
-	const struct chip_desc *chip = &chips[data->type];
-	int i;
-
-	for (i = 0; i < chip->nchans; ++i)
-		if (data->virt_adaps[i]) {
-			i2c_del_mux_adapter(data->virt_adaps[i]);
-			data->virt_adaps[i] = NULL;
-		}
 
+	i2c_del_mux_adapters(muxc);
 	return 0;
 }
 
diff --git a/drivers/i2c/muxes/i2c-mux-pinctrl.c b/drivers/i2c/muxes/i2c-mux-pinctrl.c
index e87c8f77037a..3bbb3fb1d693 100644
--- a/drivers/i2c/muxes/i2c-mux-pinctrl.c
+++ b/drivers/i2c/muxes/i2c-mux-pinctrl.c
@@ -31,7 +31,6 @@ struct i2c_mux_pinctrl {
 	struct pinctrl *pinctrl;
 	struct pinctrl_state **states;
 	struct pinctrl_state *state_idle;
-	struct i2c_adapter **busses;
 };
 
 static int i2c_mux_pinctrl_select(struct i2c_mux_core *muxc, u32 chan)
@@ -163,14 +162,9 @@ static int i2c_mux_pinctrl_probe(struct platform_device *pdev)
 		goto err;
 	}
 
-	mux->busses = devm_kzalloc(&pdev->dev,
-				   sizeof(*mux->busses) * mux->pdata->bus_count,
-				   GFP_KERNEL);
-	if (!mux->busses) {
-		dev_err(&pdev->dev, "Cannot allocate busses\n");
-		ret = -ENOMEM;
+	ret = i2c_mux_reserve_adapters(muxc, mux->pdata->bus_count);
+	if (ret)
 		goto err;
-	}
 
 	mux->pinctrl = devm_pinctrl_get(&pdev->dev);
 	if (IS_ERR(mux->pinctrl)) {
@@ -218,10 +212,9 @@ static int i2c_mux_pinctrl_probe(struct platform_device *pdev)
 		u32 bus = mux->pdata->base_bus_num ?
 				(mux->pdata->base_bus_num + i) : 0;
 
-		mux->busses[i] = i2c_add_mux_adapter(muxc, &pdev->dev,
-						     bus, i, 0);
-		if (!mux->busses[i]) {
-			ret = -ENODEV;
+		ret = i2c_add_mux_adapter(muxc, &pdev->dev,
+					  bus, i, 0);
+		if (ret) {
 			dev_err(&pdev->dev, "Failed to add adapter %d\n", i);
 			goto err_del_adapter;
 		}
@@ -230,8 +223,7 @@ static int i2c_mux_pinctrl_probe(struct platform_device *pdev)
 	return 0;
 
 err_del_adapter:
-	for (; i > 0; i--)
-		i2c_del_mux_adapter(mux->busses[i - 1]);
+	i2c_del_mux_adapters(muxc);
 	i2c_put_adapter(muxc->parent);
 err:
 	return ret;
@@ -240,14 +232,9 @@ err:
 static int i2c_mux_pinctrl_remove(struct platform_device *pdev)
 {
 	struct i2c_mux_core *muxc = platform_get_drvdata(pdev);
-	struct i2c_mux_pinctrl *mux = i2c_mux_priv(muxc);
-	int i;
-
-	for (i = 0; i < mux->pdata->bus_count; i++)
-		i2c_del_mux_adapter(mux->busses[i]);
 
+	i2c_del_mux_adapters(muxc);
 	i2c_put_adapter(muxc->parent);
-
 	return 0;
 }
 
diff --git a/drivers/i2c/muxes/i2c-mux-reg.c b/drivers/i2c/muxes/i2c-mux-reg.c
index 3b01e7809a66..5c004ff5b6ad 100644
--- a/drivers/i2c/muxes/i2c-mux-reg.c
+++ b/drivers/i2c/muxes/i2c-mux-reg.c
@@ -21,7 +21,6 @@
 #include <linux/slab.h>
 
 struct regmux {
-	struct i2c_adapter **adap; /* child busses */
 	struct i2c_mux_reg_platform_data data;
 };
 
@@ -214,13 +213,9 @@ static int i2c_mux_reg_probe(struct platform_device *pdev)
 		return -EINVAL;
 	}
 
-	mux->adap = devm_kzalloc(&pdev->dev,
-				 sizeof(*mux->adap) * mux->data.n_values,
-				 GFP_KERNEL);
-	if (!mux->adap) {
-		dev_err(&pdev->dev, "Cannot allocate i2c_adapter structure");
-		return -ENOMEM;
-	}
+	ret = i2c_mux_reserve_adapters(muxc, mux->data.n_values);
+	if (ret)
+		return ret;
 
 	muxc->select = i2c_mux_reg_select;
 	if (mux->data.idle_in_use)
@@ -232,11 +227,9 @@ static int i2c_mux_reg_probe(struct platform_device *pdev)
 		nr = mux->data.base_nr ? (mux->data.base_nr + i) : 0;
 		class = mux->data.classes ? mux->data.classes[i] : 0;
 
-		mux->adap[i] = i2c_add_mux_adapter(muxc, &pdev->dev,
-						   nr, mux->data.values[i],
-						   class);
-		if (!mux->adap[i]) {
-			ret = -ENODEV;
+		ret = i2c_add_mux_adapter(muxc, &pdev->dev, nr,
+					  mux->data.values[i], class);
+		if (ret) {
 			dev_err(&pdev->dev, "Failed to add adapter %d\n", i);
 			goto add_adapter_failed;
 		}
@@ -248,8 +241,7 @@ static int i2c_mux_reg_probe(struct platform_device *pdev)
 	return 0;
 
 add_adapter_failed:
-	for (; i > 0; i--)
-		i2c_del_mux_adapter(mux->adap[i - 1]);
+	i2c_del_mux_adapters(muxc);
 
 	return ret;
 }
@@ -257,12 +249,8 @@ add_adapter_failed:
 static int i2c_mux_reg_remove(struct platform_device *pdev)
 {
 	struct i2c_mux_core *muxc = platform_get_drvdata(pdev);
-	struct regmux *mux = i2c_mux_priv(muxc);
-	int i;
-
-	for (i = 0; i < mux->data.n_values; i++)
-		i2c_del_mux_adapter(mux->adap[i]);
 
+	i2c_del_mux_adapters(muxc);
 	i2c_put_adapter(muxc->parent);
 
 	return 0;
diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c b/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c
index 0a47396bc5be..a9a163c1c22c 100644
--- a/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c
+++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c
@@ -850,13 +850,9 @@ static int inv_mpu_probe(struct i2c_client *client,
 	st->muxc->select = inv_mpu6050_select_bypass;
 	st->muxc->deselect = inv_mpu6050_deselect_bypass;
 
-	st->mux_adapter = i2c_add_mux_adapter(st->muxc,
-					      &client->dev,
-					      0, 0, 0);
-	if (!st->mux_adapter) {
-		result = -ENODEV;
+	result = i2c_add_mux_adapter(st->muxc, &client->dev, 0, 0, 0);
+	if (result)
 		goto out_unreg_device;
-	}
 
 	result = inv_mpu_acpi_create_mux_client(st);
 	if (result)
@@ -865,7 +861,7 @@ static int inv_mpu_probe(struct i2c_client *client,
 	return 0;
 
 out_del_mux:
-	i2c_del_mux_adapter(st->mux_adapter);
+	i2c_del_mux_adapters(st->muxc);
 out_unreg_device:
 	iio_device_unregister(indio_dev);
 out_remove_trigger:
@@ -881,7 +877,7 @@ static int inv_mpu_remove(struct i2c_client *client)
 	struct inv_mpu6050_state *st = iio_priv(indio_dev);
 
 	inv_mpu_acpi_delete_mux_client(st);
-	i2c_del_mux_adapter(st->mux_adapter);
+	i2c_del_mux_adapters(st->muxc);
 	iio_device_unregister(indio_dev);
 	inv_mpu6050_remove_trigger(st);
 	iio_triggered_buffer_cleanup(indio_dev);
diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h b/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h
index d4929db4b40e..72113b59132e 100644
--- a/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h
+++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h
@@ -121,7 +121,6 @@ struct inv_mpu6050_state {
 	spinlock_t time_stamp_lock;
 	struct i2c_client *client;
 	struct i2c_mux_core *muxc;
-	struct i2c_adapter *mux_adapter;
 	struct i2c_client *mux_client;
 	unsigned int powerup_count;
 	struct inv_mpu6050_platform_data plat_data;
diff --git a/drivers/media/dvb-frontends/m88ds3103.c b/drivers/media/dvb-frontends/m88ds3103.c
index c9f8296ea421..deab5cdba01f 100644
--- a/drivers/media/dvb-frontends/m88ds3103.c
+++ b/drivers/media/dvb-frontends/m88ds3103.c
@@ -1374,7 +1374,7 @@ static struct i2c_adapter *m88ds3103_get_i2c_adapter(struct i2c_client *client)
 
 	dev_dbg(&client->dev, "\n");
 
-	return dev->i2c_adapter;
+	return dev->muxc->adapter[0];
 }
 
 static int m88ds3103_probe(struct i2c_client *client,
@@ -1476,12 +1476,9 @@ static int m88ds3103_probe(struct i2c_client *client,
 	dev->muxc->select = m88ds3103_select;
 
 	/* create mux i2c adapter for tuner */
-	dev->i2c_adapter = i2c_add_mux_adapter(dev->muxc, &client->dev,
-					       0, 0, 0);
-	if (dev->i2c_adapter == NULL) {
-		ret = -ENOMEM;
+	ret = i2c_add_mux_adapter(dev->muxc, &client->dev, 0, 0, 0);
+	if (ret)
 		goto err_kfree;
-	}
 
 	/* create dvb_frontend */
 	memcpy(&dev->fe.ops, &m88ds3103_ops, sizeof(struct dvb_frontend_ops));
@@ -1510,7 +1507,7 @@ static int m88ds3103_remove(struct i2c_client *client)
 
 	dev_dbg(&client->dev, "\n");
 
-	i2c_del_mux_adapter(dev->i2c_adapter);
+	i2c_del_mux_adapters(dev->muxc);
 
 	kfree(dev);
 	return 0;
diff --git a/drivers/media/dvb-frontends/m88ds3103_priv.h b/drivers/media/dvb-frontends/m88ds3103_priv.h
index 52d66c566ac1..c5b4e177c6ea 100644
--- a/drivers/media/dvb-frontends/m88ds3103_priv.h
+++ b/drivers/media/dvb-frontends/m88ds3103_priv.h
@@ -43,7 +43,6 @@ struct m88ds3103_dev {
 	u32 dvbv3_ber; /* for old DVBv3 API read_ber */
 	bool warm; /* FW running */
 	struct i2c_mux_core *muxc;
-	struct i2c_adapter *i2c_adapter;
 	/* auto detect chip id to do different config */
 	u8 chip_id;
 	/* main mclk is calculated for M88RS6000 dynamically */
diff --git a/drivers/media/dvb-frontends/rtl2830.c b/drivers/media/dvb-frontends/rtl2830.c
index d6330e8d5fa4..9864740722dd 100644
--- a/drivers/media/dvb-frontends/rtl2830.c
+++ b/drivers/media/dvb-frontends/rtl2830.c
@@ -712,7 +712,7 @@ static struct i2c_adapter *rtl2830_get_i2c_adapter(struct i2c_client *client)
 
 	dev_dbg(&client->dev, "\n");
 
-	return dev->adapter;
+	return dev->muxc->adapter[0];
 }
 
 /*
@@ -874,11 +874,9 @@ static int rtl2830_probe(struct i2c_client *client,
 	dev->muxc->select = rtl2830_select;
 
 	/* create muxed i2c adapter for tuner */
-	dev->adapter = i2c_add_mux_adapter(dev->muxc, &client->dev, 0, 0, 0);
-	if (dev->adapter == NULL) {
-		ret = -ENODEV;
+	ret = i2c_add_mux_adapter(dev->muxc, &client->dev, 0, 0, 0);
+	if (ret)
 		goto err_regmap_exit;
-	}
 
 	/* create dvb frontend */
 	memcpy(&dev->fe.ops, &rtl2830_ops, sizeof(dev->fe.ops));
@@ -908,7 +906,7 @@ static int rtl2830_remove(struct i2c_client *client)
 
 	dev_dbg(&client->dev, "\n");
 
-	i2c_del_mux_adapter(dev->adapter);
+	i2c_del_mux_adapters(dev->muxc);
 	regmap_exit(dev->regmap);
 	kfree(dev);
 
diff --git a/drivers/media/dvb-frontends/rtl2830_priv.h b/drivers/media/dvb-frontends/rtl2830_priv.h
index 2169c8d9c99c..da4909543da2 100644
--- a/drivers/media/dvb-frontends/rtl2830_priv.h
+++ b/drivers/media/dvb-frontends/rtl2830_priv.h
@@ -30,7 +30,6 @@ struct rtl2830_dev {
 	struct i2c_client *client;
 	struct regmap *regmap;
 	struct i2c_mux_core *muxc;
-	struct i2c_adapter *adapter;
 	struct dvb_frontend fe;
 	bool sleeping;
 	unsigned long filters;
diff --git a/drivers/media/dvb-frontends/rtl2832.c b/drivers/media/dvb-frontends/rtl2832.c
index c8fd990fdae8..99d8dbf66fd7 100644
--- a/drivers/media/dvb-frontends/rtl2832.c
+++ b/drivers/media/dvb-frontends/rtl2832.c
@@ -1074,7 +1074,7 @@ static struct i2c_adapter *rtl2832_get_i2c_adapter(struct i2c_client *client)
 	struct rtl2832_dev *dev = i2c_get_clientdata(client);
 
 	dev_dbg(&client->dev, "\n");
-	return dev->i2c_adapter_tuner;
+	return dev->muxc->adapter[0];
 }
 
 static int rtl2832_enable_slave_ts(struct i2c_client *client)
@@ -1271,12 +1271,9 @@ static int rtl2832_probe(struct i2c_client *client,
 	dev->muxc->deselect = rtl2832_deselect;
 
 	/* create muxed i2c adapter for demod tuner bus */
-	dev->i2c_adapter_tuner = i2c_add_mux_adapter(dev->muxc, &i2c->dev,
-						     0, 0, 0);
-	if (dev->i2c_adapter_tuner == NULL) {
-		ret = -ENODEV;
+	ret = i2c_add_mux_adapter(dev->muxc, &i2c->dev, 0, 0, 0);
+	if (ret)
 		goto err_regmap_exit;
-	}
 
 	/* create dvb_frontend */
 	memcpy(&dev->fe.ops, &rtl2832_ops, sizeof(struct dvb_frontend_ops));
@@ -1311,7 +1308,7 @@ static int rtl2832_remove(struct i2c_client *client)
 
 	cancel_delayed_work_sync(&dev->i2c_gate_work);
 
-	i2c_del_mux_adapter(dev->i2c_adapter_tuner);
+	i2c_del_mux_adapters(dev->muxc);
 
 	regmap_exit(dev->regmap);
 
diff --git a/drivers/media/dvb-frontends/rtl2832_priv.h b/drivers/media/dvb-frontends/rtl2832_priv.h
index 2d252bd5b8b1..6b3cd23a2c26 100644
--- a/drivers/media/dvb-frontends/rtl2832_priv.h
+++ b/drivers/media/dvb-frontends/rtl2832_priv.h
@@ -37,7 +37,6 @@ struct rtl2832_dev {
 	struct regmap_config regmap_config;
 	struct regmap *regmap;
 	struct i2c_mux_core *muxc;
-	struct i2c_adapter *i2c_adapter_tuner;
 	struct dvb_frontend fe;
 	struct delayed_work stat_work;
 	enum fe_status fe_status;
diff --git a/drivers/media/dvb-frontends/si2168.c b/drivers/media/dvb-frontends/si2168.c
index 5b1872b1bbf4..06aa496cc42c 100644
--- a/drivers/media/dvb-frontends/si2168.c
+++ b/drivers/media/dvb-frontends/si2168.c
@@ -719,16 +719,14 @@ static int si2168_probe(struct i2c_client *client,
 	dev->muxc->deselect = si2168_deselect;
 
 	/* create mux i2c adapter for tuner */
-	dev->adapter = i2c_add_mux_adapter(dev->muxc, &client->dev, 0, 0, 0);
-	if (dev->adapter == NULL) {
-		ret = -ENODEV;
+	ret = i2c_add_mux_adapter(dev->muxc, &client->dev, 0, 0, 0);
+	if (ret)
 		goto err_kfree;
-	}
 
 	/* create dvb_frontend */
 	memcpy(&dev->fe.ops, &si2168_ops, sizeof(struct dvb_frontend_ops));
 	dev->fe.demodulator_priv = client;
-	*config->i2c_adapter = dev->adapter;
+	*config->i2c_adapter = dev->muxc->adapter[0];
 	*config->fe = &dev->fe;
 	dev->ts_mode = config->ts_mode;
 	dev->ts_clock_inv = config->ts_clock_inv;
@@ -752,7 +750,7 @@ static int si2168_remove(struct i2c_client *client)
 
 	dev_dbg(&client->dev, "\n");
 
-	i2c_del_mux_adapter(dev->adapter);
+	i2c_del_mux_adapters(dev->muxc);
 
 	dev->fe.ops.release = NULL;
 	dev->fe.demodulator_priv = NULL;
diff --git a/drivers/media/dvb-frontends/si2168_priv.h b/drivers/media/dvb-frontends/si2168_priv.h
index 53efb9d562da..165bf1412063 100644
--- a/drivers/media/dvb-frontends/si2168_priv.h
+++ b/drivers/media/dvb-frontends/si2168_priv.h
@@ -30,7 +30,6 @@
 /* state struct */
 struct si2168_dev {
 	struct i2c_mux_core *muxc;
-	struct i2c_adapter *adapter;
 	struct dvb_frontend fe;
 	enum fe_delivery_system delivery_system;
 	enum fe_status fe_status;
diff --git a/drivers/media/usb/cx231xx/cx231xx-core.c b/drivers/media/usb/cx231xx/cx231xx-core.c
index d805e192e4ca..7d7b04df6a22 100644
--- a/drivers/media/usb/cx231xx/cx231xx-core.c
+++ b/drivers/media/usb/cx231xx/cx231xx-core.c
@@ -1416,8 +1416,7 @@ EXPORT_SYMBOL_GPL(cx231xx_dev_init);
 void cx231xx_dev_uninit(struct cx231xx *dev)
 {
 	/* Un Initialize I2C bus */
-	cx231xx_i2c_mux_unregister(dev, 1);
-	cx231xx_i2c_mux_unregister(dev, 0);
+	cx231xx_i2c_mux_unregister(dev);
 	cx231xx_i2c_unregister(&dev->i2c_bus[2]);
 	cx231xx_i2c_unregister(&dev->i2c_bus[1]);
 	cx231xx_i2c_unregister(&dev->i2c_bus[0]);
diff --git a/drivers/media/usb/cx231xx/cx231xx-i2c.c b/drivers/media/usb/cx231xx/cx231xx-i2c.c
index 51760bfc7cbc..2b5adb056827 100644
--- a/drivers/media/usb/cx231xx/cx231xx-i2c.c
+++ b/drivers/media/usb/cx231xx/cx231xx-i2c.c
@@ -579,23 +579,23 @@ int cx231xx_i2c_mux_register(struct cx231xx *dev, int mux_no)
 {
 	/* what is the correct mux_dev? */
 	struct device *mux_dev = dev->dev;
-
-	dev->i2c_mux_adap[mux_no] = i2c_add_mux_adapter(dev->muxc,
-				mux_dev,
-				0,
-				mux_no /* chan_id */,
-				0 /* class */);
-	if (!dev->i2c_mux_adap[mux_no])
+	int rc;
+
+	rc = i2c_add_mux_adapter(dev->muxc,
+				 mux_dev,
+				 0,
+				 mux_no /* chan_id */,
+				 0 /* class */);
+	if (rc)
 		dev_warn(dev->dev,
 			 "i2c mux %d register FAILED\n", mux_no);
 
-	return 0;
+	return rc;
 }
 
-void cx231xx_i2c_mux_unregister(struct cx231xx *dev, int mux_no)
+void cx231xx_i2c_mux_unregister(struct cx231xx *dev)
 {
-	i2c_del_mux_adapter(dev->i2c_mux_adap[mux_no]);
-	dev->i2c_mux_adap[mux_no] = NULL;
+	i2c_del_mux_adapters(dev->muxc);
 }
 
 struct i2c_adapter *cx231xx_get_i2c_adap(struct cx231xx *dev, int i2c_port)
@@ -608,9 +608,9 @@ struct i2c_adapter *cx231xx_get_i2c_adap(struct cx231xx *dev, int i2c_port)
 	case I2C_2:
 		return &dev->i2c_bus[2].i2c_adap;
 	case I2C_1_MUX_1:
-		return dev->i2c_mux_adap[0];
+		return dev->muxc->adapter[0];
 	case I2C_1_MUX_3:
-		return dev->i2c_mux_adap[1];
+		return dev->muxc->adapter[1];
 	default:
 		return NULL;
 	}
diff --git a/drivers/media/usb/cx231xx/cx231xx.h b/drivers/media/usb/cx231xx/cx231xx.h
index 72f8188e0b01..8c71fa8d777c 100644
--- a/drivers/media/usb/cx231xx/cx231xx.h
+++ b/drivers/media/usb/cx231xx/cx231xx.h
@@ -762,7 +762,7 @@ int cx231xx_i2c_register(struct cx231xx_i2c *bus);
 int cx231xx_i2c_unregister(struct cx231xx_i2c *bus);
 int cx231xx_i2c_mux_create(struct cx231xx *dev);
 int cx231xx_i2c_mux_register(struct cx231xx *dev, int mux_no);
-void cx231xx_i2c_mux_unregister(struct cx231xx *dev, int mux_no);
+void cx231xx_i2c_mux_unregister(struct cx231xx *dev);
 struct i2c_adapter *cx231xx_get_i2c_adap(struct cx231xx *dev, int i2c_port);
 
 /* Internal block control functions */
diff --git a/drivers/of/unittest.c b/drivers/of/unittest.c
index a4abd9b588b9..77ccc54cfdc9 100644
--- a/drivers/of/unittest.c
+++ b/drivers/of/unittest.c
@@ -1677,11 +1677,6 @@ static struct i2c_driver unittest_i2c_dev_driver = {
 
 #if IS_BUILTIN(CONFIG_I2C_MUX)
 
-struct unittest_i2c_mux_data {
-	int nchans;
-	struct i2c_adapter *adap[];
-};
-
 static int unittest_i2c_mux_select_chan(struct i2c_mux_core *muxc, u32 chan)
 {
 	return 0;
@@ -1690,12 +1685,11 @@ static int unittest_i2c_mux_select_chan(struct i2c_mux_core *muxc, u32 chan)
 static int unittest_i2c_mux_probe(struct i2c_client *client,
 		const struct i2c_device_id *id)
 {
-	int ret, i, nchans, size;
+	int ret, i, nchans;
 	struct device *dev = &client->dev;
 	struct i2c_adapter *adap = to_i2c_adapter(dev->parent);
 	struct device_node *np = client->dev.of_node, *child;
 	struct i2c_mux_core *muxc;
-	struct unittest_i2c_mux_data *stm;
 	u32 reg, max_reg;
 
 	dev_dbg(dev, "%s for node @%s\n", __func__, np->full_name);
@@ -1719,20 +1713,19 @@ static int unittest_i2c_mux_probe(struct i2c_client *client,
 		return -EINVAL;
 	}
 
-	size = offsetof(struct unittest_i2c_mux_data, adap[nchans]);
-	muxc = i2c_mux_alloc(dev, size);
+	muxc = i2c_mux_alloc(dev, 0);
 	if (!muxc)
 		return -ENOMEM;
 	muxc->parent = adap;
 	muxc->select = unittest_i2c_mux_select_chan;
-	stm = i2c_mux_priv(muxc);
-	stm->nchans = nchans;
+	ret = i2c_mux_reserve_adapters(muxc, nchans);
+	if (ret)
+		return ret;
 	for (i = 0; i < nchans; i++) {
-		stm->adap[i] = i2c_add_mux_adapter(muxc, dev, 0, i, 0);
-		if (!stm->adap[i]) {
+		ret = i2c_add_mux_adapter(muxc, dev, 0, i, 0);
+		if (ret) {
 			dev_err(dev, "Failed to register mux #%d\n", i);
-			for (i--; i >= 0; i--)
-				i2c_del_mux_adapter(stm->adap[i]);
+			i2c_del_mux_adapters(muxc);
 			return -ENODEV;
 		}
 	}
@@ -1747,12 +1740,9 @@ static int unittest_i2c_mux_remove(struct i2c_client *client)
 	struct device *dev = &client->dev;
 	struct device_node *np = client->dev.of_node;
 	struct i2c_mux_core *muxc = i2c_get_clientdata(client);
-	struct unittest_i2c_mux_data *stm = i2c_mux_priv(muxc);
-	int i;
 
 	dev_dbg(dev, "%s for node @%s\n", __func__, np->full_name);
-	for (i = stm->nchans - 1; i >= 0; i--)
-		i2c_del_mux_adapter(stm->adap[i]);
+	i2c_del_mux_adapters(muxc);
 	return 0;
 }
 
diff --git a/include/linux/i2c-mux.h b/include/linux/i2c-mux.h
index 5cd6e1e664e0..bfcdcc46f2a6 100644
--- a/include/linux/i2c-mux.h
+++ b/include/linux/i2c-mux.h
@@ -29,6 +29,9 @@
 
 struct i2c_mux_core {
 	struct i2c_adapter *parent;
+	struct i2c_adapter **adapter;
+	int adapters;
+	int max_adapters;
 	struct device *dev;
 
 	void *priv;
@@ -44,18 +47,20 @@ static inline void *i2c_mux_priv(struct i2c_mux_core *muxc)
 	return muxc->priv;
 }
 
+int i2c_mux_reserve_adapters(struct i2c_mux_core *muxc, int adapters);
+
 /*
  * Called to create a i2c bus on a multiplexed bus segment.
  * The mux_dev and chan_id parameters are passed to the select
  * and deselect callback functions to perform hardware-specific
  * mux control.
  */
-struct i2c_adapter *i2c_add_mux_adapter(struct i2c_mux_core *muxc,
-					struct device *mux_dev,
-					u32 force_nr, u32 chan_id,
-					unsigned int class);
+int i2c_add_mux_adapter(struct i2c_mux_core *muxc,
+			struct device *mux_dev,
+			u32 force_nr, u32 chan_id,
+			unsigned int class);
 
-void i2c_del_mux_adapter(struct i2c_adapter *adap);
+void i2c_del_mux_adapters(struct i2c_mux_core *muxc);
 
 #endif /* __KERNEL__ */
 
-- 
2.1.4