Re: [PATCH v2 10/21] ipmi: kcs_bmc: Turn the driver data-structures inside-out

["Andrew Jeffery" <andrew@xxxxxxxx>]

On Fri, 9 Apr 2021, at 13:27, Zev Weiss wrote:
> On Fri, Mar 19, 2021 at 01:27:41AM CDT, Andrew Jeffery wrote:
> >Make the KCS device drivers responsible for allocating their own memory.
> >
> >Until now the private data for the device driver was allocated internal
> >to the private data for the chardev interface. This coupling required
> >the slightly awkward API of passing through the struct size for the
> >driver private data to the chardev constructor, and then retrieving a
> >pointer to the driver private data from the allocated chardev memory.
> >
> >In addition to being awkward, the arrangement prevents the
> >implementation of alternative userspace interfaces as the device driver
> >private data is not independent.
> >
> >Peel a layer off the onion and turn the data-structures inside out by
> >exploiting container_of() and embedding `struct kcs_device` in the
> >driver private data.
> >
> >Signed-off-by: Andrew Jeffery <andrew@xxxxxxxx>
> >---
> > drivers/char/ipmi/kcs_bmc.c           | 15 +++++--
> > drivers/char/ipmi/kcs_bmc.h           | 12 ++----
> > drivers/char/ipmi/kcs_bmc_aspeed.c    | 60 ++++++++++++++++-----------
> > drivers/char/ipmi/kcs_bmc_cdev_ipmi.c | 60 ++++++++++++++++++---------
> > drivers/char/ipmi/kcs_bmc_npcm7xx.c   | 37 ++++++++++-------
> > 5 files changed, 113 insertions(+), 71 deletions(-)
> >
> >diff --git a/drivers/char/ipmi/kcs_bmc.c b/drivers/char/ipmi/kcs_bmc.c
> >index ef5c48ffe74a..709b6bdec165 100644
> >--- a/drivers/char/ipmi/kcs_bmc.c
> >+++ b/drivers/char/ipmi/kcs_bmc.c
> >@@ -44,12 +44,19 @@ int kcs_bmc_handle_event(struct kcs_bmc *kcs_bmc)
> > }
> > EXPORT_SYMBOL(kcs_bmc_handle_event);
> >
> >-struct kcs_bmc *kcs_bmc_ipmi_alloc(struct device *dev, int sizeof_priv, u32 channel);
> >-struct kcs_bmc *kcs_bmc_alloc(struct device *dev, int sizeof_priv, u32 channel)
> >+int kcs_bmc_ipmi_attach_cdev(struct kcs_bmc *kcs_bmc);
> 
> Another declaration perhaps intended for kcs_bmc.h?

These are temporary while the code gets shuffled around. The symbol 
name is an implementation detail, not a "public" part of the API; after 
some further shuffling these are eventually assigned as callbacks in an 
ops struct.

> 
> >+int kcs_bmc_add_device(struct kcs_bmc *kcs_bmc)
> > {
> >-	return kcs_bmc_ipmi_alloc(dev, sizeof_priv, channel);
> >+	return kcs_bmc_ipmi_attach_cdev(kcs_bmc);
> > }
> >-EXPORT_SYMBOL(kcs_bmc_alloc);
> >+EXPORT_SYMBOL(kcs_bmc_add_device);
> >+
> >+int kcs_bmc_ipmi_detach_cdev(struct kcs_bmc *kcs_bmc);
> 
> Here too.
> 
> >+int kcs_bmc_remove_device(struct kcs_bmc *kcs_bmc)
> >+{
> >+	return kcs_bmc_ipmi_detach_cdev(kcs_bmc);
> >+}
> >+EXPORT_SYMBOL(kcs_bmc_remove_device);
> >
> > MODULE_LICENSE("GPL v2");
> > MODULE_AUTHOR("Haiyue Wang <haiyue.wang@xxxxxxxxxxxxxxx>");
> >diff --git a/drivers/char/ipmi/kcs_bmc.h b/drivers/char/ipmi/kcs_bmc.h
> >index febea0c8deb4..bf0ae327997f 100644
> >--- a/drivers/char/ipmi/kcs_bmc.h
> >+++ b/drivers/char/ipmi/kcs_bmc.h
> >@@ -67,6 +67,8 @@ struct kcs_ioreg {
> > };
> >
> > struct kcs_bmc {
> >+	struct device *dev;
> >+
> > 	spinlock_t lock;
> >
> > 	u32 channel;
> >@@ -94,17 +96,11 @@ struct kcs_bmc {
> > 	u8 *kbuffer;
> >
> > 	struct miscdevice miscdev;
> >-
> >-	unsigned long priv[];
> > };
> >
> >-static inline void *kcs_bmc_priv(struct kcs_bmc *kcs_bmc)
> >-{
> >-	return kcs_bmc->priv;
> >-}
> >-
> > int kcs_bmc_handle_event(struct kcs_bmc *kcs_bmc);
> >-struct kcs_bmc *kcs_bmc_alloc(struct device *dev, int sizeof_priv, u32 channel);
> >+int kcs_bmc_add_device(struct kcs_bmc *kcs_bmc);
> >+int kcs_bmc_remove_device(struct kcs_bmc *kcs_bmc);
> >
> > u8 kcs_bmc_read_data(struct kcs_bmc *kcs_bmc);
> > void kcs_bmc_write_data(struct kcs_bmc *kcs_bmc, u8 data);
> >diff --git a/drivers/char/ipmi/kcs_bmc_aspeed.c b/drivers/char/ipmi/kcs_bmc_aspeed.c
> >index 630cf095560e..0416ac78ce68 100644
> >--- a/drivers/char/ipmi/kcs_bmc_aspeed.c
> >+++ b/drivers/char/ipmi/kcs_bmc_aspeed.c
> >@@ -61,6 +61,8 @@
> > #define LPC_STR4             0x11C
> >
> > struct aspeed_kcs_bmc {
> >+	struct kcs_bmc kcs_bmc;
> >+
> > 	struct regmap *map;
> > };
> >
> >@@ -69,9 +71,14 @@ struct aspeed_kcs_of_ops {
> > 	int (*get_io_address)(struct platform_device *pdev);
> > };
> >
> >+static inline struct aspeed_kcs_bmc *to_aspeed_kcs_bmc(struct kcs_bmc *kcs_bmc)
> >+{
> >+	return container_of(kcs_bmc, struct aspeed_kcs_bmc, kcs_bmc);
> >+}
> >+
> > static u8 aspeed_kcs_inb(struct kcs_bmc *kcs_bmc, u32 reg)
> > {
> >-	struct aspeed_kcs_bmc *priv = kcs_bmc_priv(kcs_bmc);
> >+	struct aspeed_kcs_bmc *priv = to_aspeed_kcs_bmc(kcs_bmc);
> > 	u32 val = 0;
> > 	int rc;
> >
> >@@ -83,7 +90,7 @@ static u8 aspeed_kcs_inb(struct kcs_bmc *kcs_bmc, u32 reg)
> >
> > static void aspeed_kcs_outb(struct kcs_bmc *kcs_bmc, u32 reg, u8 data)
> > {
> >-	struct aspeed_kcs_bmc *priv = kcs_bmc_priv(kcs_bmc);
> >+	struct aspeed_kcs_bmc *priv = to_aspeed_kcs_bmc(kcs_bmc);
> > 	int rc;
> >
> > 	rc = regmap_write(priv->map, reg, data);
> >@@ -92,7 +99,7 @@ static void aspeed_kcs_outb(struct kcs_bmc *kcs_bmc, u32 reg, u8 data)
> >
> > static void aspeed_kcs_updateb(struct kcs_bmc *kcs_bmc, u32 reg, u8 mask, u8 val)
> > {
> >-	struct aspeed_kcs_bmc *priv = kcs_bmc_priv(kcs_bmc);
> >+	struct aspeed_kcs_bmc *priv = to_aspeed_kcs_bmc(kcs_bmc);
> > 	int rc;
> >
> > 	rc = regmap_update_bits(priv->map, reg, mask, val);
> >@@ -114,7 +121,7 @@ static void aspeed_kcs_updateb(struct kcs_bmc *kcs_bmc, u32 reg, u8 mask, u8 val
> >  */
> > static void aspeed_kcs_set_address(struct kcs_bmc *kcs_bmc, u16 addr)
> > {
> >-	struct aspeed_kcs_bmc *priv = kcs_bmc_priv(kcs_bmc);
> >+	struct aspeed_kcs_bmc *priv = to_aspeed_kcs_bmc(kcs_bmc);
> >
> > 	switch (kcs_bmc->channel) {
> > 	case 1:
> >@@ -148,7 +155,7 @@ static void aspeed_kcs_set_address(struct kcs_bmc *kcs_bmc, u16 addr)
> >
> > static void aspeed_kcs_enable_channel(struct kcs_bmc *kcs_bmc, bool enable)
> > {
> >-	struct aspeed_kcs_bmc *priv = kcs_bmc_priv(kcs_bmc);
> >+	struct aspeed_kcs_bmc *priv = to_aspeed_kcs_bmc(kcs_bmc);
> >
> > 	switch (kcs_bmc->channel) {
> > 	case 1:
> >@@ -323,16 +330,16 @@ static int aspeed_kcs_of_v2_get_io_address(struct platform_device *pdev)
> > static int aspeed_kcs_probe(struct platform_device *pdev)
> > {
> > 	const struct aspeed_kcs_of_ops *ops;
> >-	struct device *dev = &pdev->dev;
> >+	struct aspeed_kcs_bmc *priv;
> > 	struct kcs_bmc *kcs_bmc;
> > 	struct device_node *np;
> > 	int rc, channel, addr;
> >
> >-	np = dev->of_node->parent;
> >+	np = pdev->dev.of_node->parent;
> > 	if (!of_device_is_compatible(np, "aspeed,ast2400-lpc-v2") &&
> > 	    !of_device_is_compatible(np, "aspeed,ast2500-lpc-v2") &&
> > 	    !of_device_is_compatible(np, "aspeed,ast2600-lpc-v2")) {
> >-		dev_err(dev, "unsupported LPC device binding\n");
> >+		dev_err(&pdev->dev, "unsupported LPC device binding\n");
> > 		return -ENODEV;
> > 	}
> > 	ops = of_device_get_match_data(&pdev->dev);
> >@@ -343,18 +350,27 @@ static int aspeed_kcs_probe(struct platform_device *pdev)
> > 	if (channel < 0)
> > 		return channel;
> >
> >-	kcs_bmc = kcs_bmc_alloc(&pdev->dev, sizeof(struct aspeed_kcs_bmc), channel);
> >-	if (!kcs_bmc)
> >+	addr = ops->get_io_address(pdev);
> >+	if (addr < 0)
> >+		return addr;
> >+
> >+	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
> >+	if (!priv)
> > 		return -ENOMEM;
> >
> >+	kcs_bmc = &priv->kcs_bmc;
> >+	kcs_bmc->dev = &pdev->dev;
> >+	kcs_bmc->channel = channel;
> > 	kcs_bmc->ioreg = ast_kcs_bmc_ioregs[channel - 1];
> > 	kcs_bmc->io_inputb = aspeed_kcs_inb;
> > 	kcs_bmc->io_outputb = aspeed_kcs_outb;
> > 	kcs_bmc->io_updateb = aspeed_kcs_updateb;
> >
> >-	addr = ops->get_io_address(pdev);
> >-	if (addr < 0)
> >-		return addr;
> >+	priv->map = syscon_node_to_regmap(pdev->dev.parent->of_node);
> >+	if (IS_ERR(priv->map)) {
> >+		dev_err(&pdev->dev, "Couldn't get regmap\n");
> >+		return -ENODEV;
> >+	}
> 
> The reanimated priv->map initialization I suspect wasn't meant to
> have been removed in the first place...

Yeah, I'll have to go back and figure out what went wrong there!

Thanks for catching that.

> 
> >
> > 	aspeed_kcs_set_address(kcs_bmc, addr);
> >
> >@@ -362,29 +378,25 @@ static int aspeed_kcs_probe(struct platform_device *pdev)
> > 	if (rc)
> > 		return rc;
> >
> >-	dev_set_drvdata(dev, kcs_bmc);
> >+	platform_set_drvdata(pdev, priv);
> >
> > 	aspeed_kcs_enable_channel(kcs_bmc, true);
> >
> >-	rc = misc_register(&kcs_bmc->miscdev);
> >-	if (rc) {
> >-		dev_err(dev, "Unable to register device\n");
> >+	rc = kcs_bmc_add_device(&priv->kcs_bmc);
> >+	if (rc < 0)
> > 		return rc;
> >-	}
> >
> >-	dev_dbg(&pdev->dev,
> >-		"Probed KCS device %d (IDR=0x%x, ODR=0x%x, STR=0x%x)\n",
> >-		kcs_bmc->channel, kcs_bmc->ioreg.idr, kcs_bmc->ioreg.odr,
> >-		kcs_bmc->ioreg.str);
> >+	dev_info(&pdev->dev, "Initialised channel %d at 0x%x\n", kcs_bmc->channel, addr);
> 
> Is the dbg->info change here intentional?  (I have no particular
> objection if so, but it's often a change I make myself during
> testing/debugging and then forget to revert...)

Yeah, it was possibly something I forgot to revert. If others have 
issues with it staying at dev_info() I'll switch it back.

> 
> >
> > 	return 0;
> > }
> >
> > static int aspeed_kcs_remove(struct platform_device *pdev)
> > {
> >-	struct kcs_bmc *kcs_bmc = dev_get_drvdata(&pdev->dev);
> >+	struct aspeed_kcs_bmc *priv = platform_get_drvdata(pdev);
> >+	struct kcs_bmc *kcs_bmc = &priv->kcs_bmc;
> >
> >-	misc_deregister(&kcs_bmc->miscdev);
> >+	kcs_bmc_remove_device(kcs_bmc);
> 
> Should we propagate the return value outward here?

Probably!

> 
> >
> > 	return 0;
> > }
> >diff --git a/drivers/char/ipmi/kcs_bmc_cdev_ipmi.c b/drivers/char/ipmi/kcs_bmc_cdev_ipmi.c
> >index 82c77994e481..0ca71c135a1a 100644
> >--- a/drivers/char/ipmi/kcs_bmc_cdev_ipmi.c
> >+++ b/drivers/char/ipmi/kcs_bmc_cdev_ipmi.c
> >@@ -382,7 +382,7 @@ static int kcs_bmc_ipmi_release(struct inode *inode, struct file *filp)
> > 	return 0;
> > }
> >
> >-static const struct file_operations kcs_bmc_fops = {
> >+static const struct file_operations kcs_bmc_ipmi_fops = {
> > 	.owner          = THIS_MODULE,
> > 	.open           = kcs_bmc_ipmi_open,
> > 	.read           = kcs_bmc_ipmi_read,
> >@@ -392,36 +392,58 @@ static const struct file_operations kcs_bmc_fops = {
> > 	.unlocked_ioctl = kcs_bmc_ipmi_ioctl,
> > };
> >
> >-struct kcs_bmc *kcs_bmc_ipmi_alloc(struct device *dev, int sizeof_priv, u32 channel);
> >-struct kcs_bmc *kcs_bmc_ipmi_alloc(struct device *dev, int sizeof_priv, u32 channel)
> >+int kcs_bmc_ipmi_attach_cdev(struct kcs_bmc *kcs_bmc);
> 
> Errant declaration again?

As previously explained.

> 
> >+int kcs_bmc_ipmi_attach_cdev(struct kcs_bmc *kcs_bmc)
> > {
> >-	struct kcs_bmc *kcs_bmc;
> >-
> >-	kcs_bmc = devm_kzalloc(dev, sizeof(*kcs_bmc) + sizeof_priv, GFP_KERNEL);
> >-	if (!kcs_bmc)
> >-		return NULL;
> >+	int rc;
> >
> > 	spin_lock_init(&kcs_bmc->lock);
> >-	kcs_bmc->channel = channel;
> >-
> > 	mutex_init(&kcs_bmc->mutex);
> > 	init_waitqueue_head(&kcs_bmc->queue);
> >
> >-	kcs_bmc->data_in = devm_kmalloc(dev, KCS_MSG_BUFSIZ, GFP_KERNEL);
> >-	kcs_bmc->data_out = devm_kmalloc(dev, KCS_MSG_BUFSIZ, GFP_KERNEL);
> >-	kcs_bmc->kbuffer = devm_kmalloc(dev, KCS_MSG_BUFSIZ, GFP_KERNEL);
> >+	kcs_bmc->data_in = devm_kmalloc(kcs_bmc->dev, KCS_MSG_BUFSIZ, GFP_KERNEL);
> >+	kcs_bmc->data_out = devm_kmalloc(kcs_bmc->dev, KCS_MSG_BUFSIZ, GFP_KERNEL);
> >+	kcs_bmc->kbuffer = devm_kmalloc(kcs_bmc->dev, KCS_MSG_BUFSIZ, GFP_KERNEL);
> >
> > 	kcs_bmc->miscdev.minor = MISC_DYNAMIC_MINOR;
> >-	kcs_bmc->miscdev.name = devm_kasprintf(dev, GFP_KERNEL, "%s%u",
> >-					       DEVICE_NAME, channel);
> >+	kcs_bmc->miscdev.name = devm_kasprintf(kcs_bmc->dev, GFP_KERNEL, "%s%u",
> >+					       DEVICE_NAME, kcs_bmc->channel);
> > 	if (!kcs_bmc->data_in || !kcs_bmc->data_out || !kcs_bmc->kbuffer ||
> > 	    !kcs_bmc->miscdev.name)
> >-		return NULL;
> >-	kcs_bmc->miscdev.fops = &kcs_bmc_fops;
> >+		return -ENOMEM;
> >
> >-	return kcs_bmc;
> >+	kcs_bmc->miscdev.fops = &kcs_bmc_ipmi_fops;
> >+
> >+	rc = misc_register(&kcs_bmc->miscdev);
> >+	if (rc) {
> >+		dev_err(kcs_bmc->dev, "Unable to register device: %d\n", rc);
> >+		return rc;
> >+	}
> >+
> >+	dev_info(kcs_bmc->dev, "Initialised IPMI client for channel %d", kcs_bmc->channel);
> >+
> >+	return 0;
> >+}
> >+EXPORT_SYMBOL(kcs_bmc_ipmi_attach_cdev);
> >+
> >+int kcs_bmc_ipmi_detach_cdev(struct kcs_bmc *kcs_bmc);
> 
> Same here.

Same explanation.

> 
> >+int kcs_bmc_ipmi_detach_cdev(struct kcs_bmc *kcs_bmc)
> >+{
> >+	misc_deregister(&kcs_bmc->miscdev);
> >+
> >+	spin_lock_irq(&kcs_bmc->lock);
> >+	kcs_bmc->running = 0;
> >+	kcs_bmc_ipmi_force_abort(kcs_bmc);
> >+	spin_unlock_irq(&kcs_bmc->lock);
> >+
> >+	devm_kfree(kcs_bmc->dev, kcs_bmc->kbuffer);
> >+	devm_kfree(kcs_bmc->dev, kcs_bmc->data_out);
> >+	devm_kfree(kcs_bmc->dev, kcs_bmc->data_in);
> >+	devm_kfree(kcs_bmc->dev, kcs_bmc);
> >+
> >+	return 0;
> > }
> >-EXPORT_SYMBOL(kcs_bmc_ipmi_alloc);
> >+EXPORT_SYMBOL(kcs_bmc_ipmi_detach_cdev);
> >
> > MODULE_LICENSE("GPL v2");
> > MODULE_AUTHOR("Haiyue Wang <haiyue.wang@xxxxxxxxxxxxxxx>");
> >diff --git a/drivers/char/ipmi/kcs_bmc_npcm7xx.c b/drivers/char/ipmi/kcs_bmc_npcm7xx.c
> >index 1f44aadec9e8..5d017498dc69 100644
> >--- a/drivers/char/ipmi/kcs_bmc_npcm7xx.c
> >+++ b/drivers/char/ipmi/kcs_bmc_npcm7xx.c
> >@@ -65,6 +65,8 @@ struct npcm7xx_kcs_reg {
> > };
> >
> > struct npcm7xx_kcs_bmc {
> >+	struct kcs_bmc kcs_bmc;
> >+
> > 	struct regmap *map;
> >
> > 	const struct npcm7xx_kcs_reg *reg;
> >@@ -76,9 +78,14 @@ static const struct npcm7xx_kcs_reg npcm7xx_kcs_reg_tbl[KCS_CHANNEL_MAX] = {
> > 	{ .sts = KCS3ST, .dob = KCS3DO, .dib = KCS3DI, .ctl = KCS3CTL, .ie = KCS3IE },
> > };
> >
> >+static inline struct npcm7xx_kcs_bmc *to_npcm7xx_kcs_bmc(struct kcs_bmc *kcs_bmc)
> >+{
> >+	return container_of(kcs_bmc, struct npcm7xx_kcs_bmc, kcs_bmc);
> >+}
> >+
> > static u8 npcm7xx_kcs_inb(struct kcs_bmc *kcs_bmc, u32 reg)
> > {
> >-	struct npcm7xx_kcs_bmc *priv = kcs_bmc_priv(kcs_bmc);
> >+	struct npcm7xx_kcs_bmc *priv = to_npcm7xx_kcs_bmc(kcs_bmc);
> > 	u32 val = 0;
> > 	int rc;
> >
> >@@ -90,7 +97,7 @@ static u8 npcm7xx_kcs_inb(struct kcs_bmc *kcs_bmc, u32 reg)
> >
> > static void npcm7xx_kcs_outb(struct kcs_bmc *kcs_bmc, u32 reg, u8 data)
> > {
> >-	struct npcm7xx_kcs_bmc *priv = kcs_bmc_priv(kcs_bmc);
> >+	struct npcm7xx_kcs_bmc *priv = to_npcm7xx_kcs_bmc(kcs_bmc);
> > 	int rc;
> >
> > 	rc = regmap_write(priv->map, reg, data);
> >@@ -99,7 +106,7 @@ static void npcm7xx_kcs_outb(struct kcs_bmc *kcs_bmc, u32 reg, u8 data)
> >
> > static void npcm7xx_kcs_updateb(struct kcs_bmc *kcs_bmc, u32 reg, u8 mask, u8 data)
> > {
> >-	struct npcm7xx_kcs_bmc *priv = kcs_bmc_priv(kcs_bmc);
> >+	struct npcm7xx_kcs_bmc *priv = to_npcm7xx_kcs_bmc(kcs_bmc);
> > 	int rc;
> >
> > 	rc = regmap_update_bits(priv->map, reg, mask, data);
> >@@ -108,7 +115,7 @@ static void npcm7xx_kcs_updateb(struct kcs_bmc *kcs_bmc, u32 reg, u8 mask, u8 da
> >
> > static void npcm7xx_kcs_enable_channel(struct kcs_bmc *kcs_bmc, bool enable)
> > {
> >-	struct npcm7xx_kcs_bmc *priv = kcs_bmc_priv(kcs_bmc);
> >+	struct npcm7xx_kcs_bmc *priv = to_npcm7xx_kcs_bmc(kcs_bmc);
> >
> > 	regmap_update_bits(priv->map, priv->reg->ctl, KCS_CTL_IBFIE,
> > 			   enable ? KCS_CTL_IBFIE : 0);
> >@@ -155,11 +162,10 @@ static int npcm7xx_kcs_probe(struct platform_device *pdev)
> > 		return -ENODEV;
> > 	}
> >
> >-	kcs_bmc = kcs_bmc_alloc(dev, sizeof(*priv), chan);
> >-	if (!kcs_bmc)
> >+	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
> >+	if (!priv)
> > 		return -ENOMEM;
> >
> >-	priv = kcs_bmc_priv(kcs_bmc);
> > 	priv->map = syscon_node_to_regmap(dev->parent->of_node);
> > 	if (IS_ERR(priv->map)) {
> > 		dev_err(dev, "Couldn't get regmap\n");
> >@@ -167,6 +173,9 @@ static int npcm7xx_kcs_probe(struct platform_device *pdev)
> > 	}
> > 	priv->reg = &npcm7xx_kcs_reg_tbl[chan - 1];
> >
> >+	kcs_bmc = &priv->kcs_bmc;
> >+	kcs_bmc->dev = &pdev->dev;
> >+	kcs_bmc->channel = chan;
> > 	kcs_bmc->ioreg.idr = priv->reg->dib;
> > 	kcs_bmc->ioreg.odr = priv->reg->dob;
> > 	kcs_bmc->ioreg.str = priv->reg->sts;
> >@@ -174,31 +183,27 @@ static int npcm7xx_kcs_probe(struct platform_device *pdev)
> > 	kcs_bmc->io_outputb = npcm7xx_kcs_outb;
> > 	kcs_bmc->io_updateb = npcm7xx_kcs_updateb;
> >
> >-	dev_set_drvdata(dev, kcs_bmc);
> >+	platform_set_drvdata(pdev, priv);
> >
> > 	npcm7xx_kcs_enable_channel(kcs_bmc, true);
> > 	rc = npcm7xx_kcs_config_irq(kcs_bmc, pdev);
> > 	if (rc)
> > 		return rc;
> >
> >-	rc = misc_register(&kcs_bmc->miscdev);
> >-	if (rc) {
> >-		dev_err(dev, "Unable to register device\n");
> >-		return rc;
> >-	}
> >
> > 	pr_info("channel=%u idr=0x%x odr=0x%x str=0x%x\n",
> > 		chan,
> > 		kcs_bmc->ioreg.idr, kcs_bmc->ioreg.odr, kcs_bmc->ioreg.str);
> >
> >-	return 0;
> >+	return kcs_bmc_add_device(kcs_bmc);
> > }
> >
> > static int npcm7xx_kcs_remove(struct platform_device *pdev)
> > {
> >-	struct kcs_bmc *kcs_bmc = dev_get_drvdata(&pdev->dev);
> >+	struct npcm7xx_kcs_bmc *priv = platform_get_drvdata(pdev);
> >+	struct kcs_bmc *kcs_bmc = &priv->kcs_bmc;
> >
> >-	misc_deregister(&kcs_bmc->miscdev);
> >+	kcs_bmc_remove_device(kcs_bmc);
> 
> As with the corresponding aspeed code, should we propagate the return
> value here?

I'll address this.

Thanks for the review!

Andrew