fsi: Convert misc devs to proper chardevs and more

131 lines not on this page · raw message

index 141fd38d061f..ec3be0d5b786 100644
@@ -76,8 +76,18 @@ extern int fsi_slave_read(struct fsi_slave *slave, uint32_t addr,
 extern int fsi_slave_write(struct fsi_slave *slave, uint32_t addr,
 		const void *val, size_t size);
 
+extern struct bus_type fsi_bus_type;
+extern const struct device_type fsi_cdev_type;
 
+enum fsi_dev_type {
+	fsi_dev_cfam,
+	fsi_dev_sbefifo,
+	fsi_dev_scom,
+	fsi_dev_occ
+};
 
-extern struct bus_type fsi_bus_type;
+extern int fsi_get_new_minor(struct fsi_device *fdev, enum fsi_dev_type type,
+			     dev_t *out_dev, int *out_index);
+extern void fsi_free_minor(dev_t dev);
 
 #endif /* LINUX_FSI_H */

index 33a5d9a43a07..8a185f53c9d8 100644
@@ -17,9 +17,8 @@
 #include <linux/fs.h>
 #include <linux/fsi.h>
 #include <linux/fsi-sbefifo.h>
-#include <linux/idr.h>
 #include <linux/kernel.h>
-#include <linux/miscdevice.h>
+#include <linux/cdev.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/of.h>

@@ -118,11 +117,11 @@ struct sbefifo {
 	uint32_t		magic;
 #define SBEFIFO_MAGIC		0x53424546 /* "SBEF" */
 	struct fsi_device	*fsi_dev;
-	struct miscdevice	mdev;
+	struct device		dev;
+	struct cdev		cdev;
 	struct mutex		lock;
-	char			name[32];
-	int			idx;
 	bool			broken;
+	bool			dead;
 	bool			async_ffdc;
 };
 

@@ -133,9 +132,9 @@ struct sbefifo_user {
 	size_t			pending_len;
 };
 
-static DEFINE_IDA(sbefifo_ida);
 static DEFINE_MUTEX(sbefifo_ffdc_mutex);
 
+
 static void __sbefifo_dump_ffdc(struct device *dev, const __be32 *ffdc,
 				size_t ffdc_sz, bool internal)
 {

@@ -667,6 +666,9 @@ static int __sbefifo_submit(struct sbefifo *sbefifo,
 	struct device *dev = &sbefifo->fsi_dev->dev;
 	int rc;
 
+	if (sbefifo->dead)
+		return -ENODEV;
+
 	if (cmd_len < 2 || be32_to_cpu(command[0]) != cmd_len) {
 		dev_vdbg(dev, "Invalid command len %zd (header: %d)\n",
 			 cmd_len, be32_to_cpu(command[0]));

@@ -751,8 +753,7 @@ EXPORT_SYMBOL_GPL(sbefifo_submit);
  */
 static int sbefifo_user_open(struct inode *inode, struct file *file)
 {
-	struct sbefifo *sbefifo = container_of(file->private_data,
-					       struct sbefifo, mdev);
+	struct sbefifo *sbefifo = container_of(inode->i_cdev, struct sbefifo, cdev);
 	struct sbefifo_user *user;
 
 	user = kzalloc(sizeof(struct sbefifo_user), GFP_KERNEL);

@@ -889,6 +890,14 @@ static const struct file_operations sbefifo_fops = {
 	.release	= sbefifo_user_release,
 };
 
+static void sbefifo_free(struct device *dev)
+{
+	struct sbefifo *sbefifo = container_of(dev, struct sbefifo, dev);
+
+	put_device(&sbefifo->fsi_dev->dev);
+	kfree(sbefifo);
+}
+
 /*
  * Probe/remove
  */

@@ -900,15 +909,23 @@ static int sbefifo_probe(struct device *dev)
 	struct device_node *np;
 	struct platform_device *child;
 	char child_name[32];
-	int rc, child_idx = 0;
+	int rc, didx, child_idx = 0;
 
 	dev_dbg(dev, "Found sbefifo device\n");
 
-	sbefifo = devm_kzalloc(dev, sizeof(*sbefifo), GFP_KERNEL);
+	sbefifo = kzalloc(sizeof(*sbefifo), GFP_KERNEL);
 	if (!sbefifo)
 		return -ENOMEM;
+
+	/* Grab a reference to the device (parent of our cdev), we'll drop it later */
+	if (!get_device(dev)) {
+		return -ENODEV;
+		kfree(sbefifo);
+	}
+
 	sbefifo->magic = SBEFIFO_MAGIC;
 	sbefifo->fsi_dev = fsi_dev;
+	dev_set_drvdata(dev, sbefifo);
 	mutex_init(&sbefifo->lock);
 
 	/*

@@ -919,28 +936,30 @@ static int sbefifo_probe(struct device *dev)
 	if (rc && rc != -ESHUTDOWN)
 		dev_err(dev, "Initial HW cleanup failed, will retry later\n");
 
-	sbefifo->idx = ida_simple_get(&sbefifo_ida, 1, INT_MAX, GFP_KERNEL);
-	snprintf(sbefifo->name, sizeof(sbefifo->name), "sbefifo%d",
-		 sbefifo->idx);
+	/* Create chardev for userspace access */
+	sbefifo->dev.type = &fsi_cdev_type;
+	sbefifo->dev.parent = dev;
+	sbefifo->dev.release = sbefifo_free;
+	device_initialize(&sbefifo->dev);
 
-	dev_set_drvdata(dev, sbefifo);
+	/* Allocate a minor in the FSI space */
+	rc = fsi_get_new_minor(fsi_dev, fsi_dev_sbefifo, &sbefifo->dev.devt, &didx);
+	if (rc)
+		goto err;
 
-	/* Create misc chardev for userspace access */
-	sbefifo->mdev.minor = MISC_DYNAMIC_MINOR;
-	sbefifo->mdev.fops = &sbefifo_fops;
-	sbefifo->mdev.name = sbefifo->name;
-	sbefifo->mdev.parent = dev;
-	rc = misc_register(&sbefifo->mdev);
+	dev_set_name(&sbefifo->dev, "sbefifo%d", didx);
+	cdev_init(&sbefifo->cdev, &sbefifo_fops);
+	rc = cdev_device_add(&sbefifo->cdev, &sbefifo->dev);
 	if (rc) {
-		dev_err(dev, "Failed to register miscdevice: %d\n", rc);
-		ida_simple_remove(&sbefifo_ida, sbefifo->idx);
-		return rc;
+		dev_err(dev, "Error %d creating char device %s\n",
+			rc, dev_name(&sbefifo->dev));
+		goto err_free_minor;
 	}
 
 	/* Create platform devs for dts child nodes (occ, etc) */
 	for_each_available_child_of_node(dev->of_node, np) {
 		snprintf(child_name, sizeof(child_name), "%s-dev%d",
-			 sbefifo->name, child_idx++);
+			 dev_name(&sbefifo->dev), child_idx++);
 		child = of_platform_device_create(np, child_name, dev);
 		if (!child)
 			dev_warn(dev, "failed to create child %s dev\n",

@@ -948,6 +967,11 @@ static int sbefifo_probe(struct device *dev)
 	}
 
 	return 0;
+ err_free_minor:
+	fsi_free_minor(sbefifo->dev.devt);
+ err:
+	put_device(&sbefifo->dev);
+	return rc;
 }
 
 static int sbefifo_unregister_child(struct device *dev, void *data)

@@ -967,10 +991,14 @@ static int sbefifo_remove(struct device *dev)
 
 	dev_dbg(dev, "Removing sbefifo device...\n");
 
-	misc_deregister(&sbefifo->mdev);
-	device_for_each_child(dev, NULL, sbefifo_unregister_child);
+	mutex_lock(&sbefifo->lock);
+	sbefifo->dead = true;
+	mutex_unlock(&sbefifo->lock);
 
-	ida_simple_remove(&sbefifo_ida, sbefifo->idx);
+	cdev_device_del(&sbefifo->cdev, &sbefifo->dev);
+	fsi_free_minor(sbefifo->dev.devt);
+	device_for_each_child(dev, NULL, sbefifo_unregister_child);
+	put_device(&sbefifo->dev);
 
 	return 0;
 }

@@ -1001,8 +1029,6 @@ static int sbefifo_init(void)
 static void sbefifo_exit(void)
 {
 	fsi_driver_unregister(&sbefifo_drv);
-
-	ida_destroy(&sbefifo_ida);
 }
 
 module_init(sbefifo_init);

index 39c74351f1bf..0f303a700f69 100644
@@ -20,9 +20,8 @@
 #include <linux/fs.h>
 #include <linux/uaccess.h>
 #include <linux/slab.h>
-#include <linux/miscdevice.h>
+#include <linux/cdev.h>
 #include <linux/list.h>
-#include <linux/idr.h>
 
 #include <uapi/linux/fsi.h>
 

@@ -77,18 +76,12 @@
 struct scom_device {
 	struct list_head link;
 	struct fsi_device *fsi_dev;
-	struct miscdevice mdev;
+	struct device dev;
+	struct cdev cdev;
 	struct mutex lock;
-	char	name[32];
-	int	idx;
+	bool dead;
 };
 
-#define to_scom_dev(x)		container_of((x), struct scom_device, mdev)
-
-static struct list_head scom_devices;
-
-static DEFINE_IDA(scom_ida);
-
 static int __put_scom(struct scom_device *scom_dev, uint64_t value,
 		      uint32_t addr, uint32_t *status)
 {

@@ -374,9 +367,7 @@ static int get_scom(struct scom_device *scom, uint64_t *value,
 static ssize_t scom_read(struct file *filep, char __user *buf, size_t len,
 			 loff_t *offset)
 {
-	struct miscdevice *mdev =
-				(struct miscdevice *)filep->private_data;
-	struct scom_device *scom = to_scom_dev(mdev);
+	struct scom_device *scom = filep->private_data;
 	struct device *dev = &scom->fsi_dev->dev;
 	uint64_t val;
 	int rc;

@@ -385,7 +376,10 @@ static ssize_t scom_read(struct file *filep, char __user *buf, size_t len,
 		return -EINVAL;
 
 	mutex_lock(&scom->lock);
-	rc = get_scom(scom, &val, *offset);
+	if (scom->dead)
+		rc = -ENODEV;
+	else
+		rc = get_scom(scom, &val, *offset);
 	mutex_unlock(&scom->lock);
 	if (rc) {
 		dev_dbg(dev, "get_scom fail:%d\n", rc);

@@ -403,8 +397,7 @@ static ssize_t scom_write(struct file *filep, const char __user *buf,
 			  size_t len, loff_t *offset)
 {
 	int rc;
-	struct miscdevice *mdev = filep->private_data;
-	struct scom_device *scom = to_scom_dev(mdev);
+	struct scom_device *scom = filep->private_data;
 	struct device *dev = &scom->fsi_dev->dev;
 	uint64_t val;
 

@@ -418,7 +411,10 @@ static ssize_t scom_write(struct file *filep, const char __user *buf,
 	}
 
 	mutex_lock(&scom->lock);
-	rc = put_scom(scom, val, *offset);
+	if (scom->dead)
+		rc = -ENODEV;
+	else
+		rc = put_scom(scom, val, *offset);
 	mutex_unlock(&scom->lock);
 	if (rc) {
 		dev_dbg(dev, "put_scom failed with:%d\n", rc);

@@ -532,12 +528,15 @@ static int scom_check(struct scom_device *scom, void __user *argp)
 
 static long scom_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 {
-	struct miscdevice *mdev = file->private_data;
-	struct scom_device *scom = to_scom_dev(mdev);
+	struct scom_device *scom = file->private_data;
 	void __user *argp = (void __user *)arg;
 	int rc = -ENOTTY;
 
 	mutex_lock(&scom->lock);
+	if (scom->dead) {
+		mutex_unlock(&scom->lock);
+		return -ENODEV;
+	}
 	switch(cmd) {
 	case FSI_SCOM_CHECK:
 		rc = scom_check(scom, argp);

@@ -556,48 +555,88 @@ static long scom_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 	return rc;
 }
 
+static int scom_open(struct inode *inode, struct file *file)
+{
+	struct scom_device *scom = container_of(inode->i_cdev, struct scom_device, cdev);
+
+	file->private_data = scom;
+
+	return 0;
+}
+
 static const struct file_operations scom_fops = {
 	.owner		= THIS_MODULE,
+	.open		= scom_open,
 	.llseek		= scom_llseek,
 	.read		= scom_read,
 	.write		= scom_write,
 	.unlocked_ioctl	= scom_ioctl,
 };
 
+static void scom_free(struct device *dev)
+{
+	struct scom_device *scom = container_of(dev, struct scom_device, dev);
+
+	put_device(&scom->fsi_dev->dev);
+	kfree(scom);
+}
+
 static int scom_probe(struct device *dev)
 {
 	struct fsi_device *fsi_dev = to_fsi_dev(dev);
 	struct scom_device *scom;
+	int rc, didx;
 
-	scom = devm_kzalloc(dev, sizeof(*scom), GFP_KERNEL);
+	scom = kzalloc(sizeof(*scom), GFP_KERNEL);
 	if (!scom)
 		return -ENOMEM;
-
+	dev_set_drvdata(dev, scom);
 	mutex_init(&scom->lock);
-	scom->idx = ida_simple_get(&scom_ida, 1, INT_MAX, GFP_KERNEL);
-	snprintf(scom->name, sizeof(scom->name), "scom%d", scom->idx);
-	scom->fsi_dev = fsi_dev;
-	scom->mdev.minor = MISC_DYNAMIC_MINOR;
-	scom->mdev.fops = &scom_fops;
-	scom->mdev.name = scom->name;
-	scom->mdev.parent = dev;
-	list_add(&scom->link, &scom_devices);
-
-	return misc_register(&scom->mdev);
+
+	/* Grab a reference to the device (parent of our cdev), we'll drop it later */
+	if (!get_device(dev)) {
+		kfree(scom);
+		return -ENODEV;
+	}
+
+	/* Create chardev for userspace access */
+	scom->dev.type = &fsi_cdev_type;
+	scom->dev.parent = dev;
+	scom->dev.release = scom_free;
+	device_initialize(&scom->dev);
+
+	/* Allocate a minor in the FSI space */
+	rc = fsi_get_new_minor(fsi_dev, fsi_dev_scom, &scom->dev.devt, &didx);
+	if (rc)
+		goto err;
+
+	dev_set_name(&scom->dev, "scom%d", didx);
+	cdev_init(&scom->cdev, &scom_fops);
+	rc = cdev_device_add(&scom->cdev, &scom->dev);
+	if (rc) {
+		dev_err(dev, "Error %d creating char device %s\n",
+			rc, dev_name(&scom->dev));
+		goto err_free_minor;
+	}
+
+	return 0;
+ err_free_minor:
+	fsi_free_minor(scom->dev.devt);
+ err:
+	put_device(&scom->dev);
+	return rc;
 }
 
 static int scom_remove(struct device *dev)
 {
-	struct scom_device *scom, *scom_tmp;
-	struct fsi_device *fsi_dev = to_fsi_dev(dev);
+	struct scom_device *scom = dev_get_drvdata(dev);
 
-	list_for_each_entry_safe(scom, scom_tmp, &scom_devices, link) {
-		if (scom->fsi_dev == fsi_dev) {
-			list_del(&scom->link);
-			ida_simple_remove(&scom_ida, scom->idx);
-			misc_deregister(&scom->mdev);
-		}
-	}
+	mutex_lock(&scom->lock);
+	scom->dead = true;
+	mutex_unlock(&scom->lock);
+	cdev_device_del(&scom->cdev, &scom->dev);
+	fsi_free_minor(scom->dev.devt);
+	put_device(&scom->dev);
 
 	return 0;
 }

@@ -622,20 +661,11 @@ static struct fsi_driver scom_drv = {
 
 static int scom_init(void)
 {
-	INIT_LIST_HEAD(&scom_devices);
 	return fsi_driver_register(&scom_drv);
 }
 
 static void scom_exit(void)
 {
-	struct list_head *pos;
-	struct scom_device *scom;
-
-	list_for_each(pos, &scom_devices) {
-		scom = list_entry(pos, struct scom_device, link);
-		misc_deregister(&scom->mdev);
-		devm_kfree(&scom->fsi_dev->dev, scom);
-	}
 	fsi_driver_unregister(&scom_drv);
 }
 

index faa1760a5a40..dea5bd48acc5 100644
@@ -11,6 +11,11 @@
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
+ *
+ * TODO:
+ *  - Rework topology
+ *  - s/chip_id/chip_loc
+ *  - s/cfam/chip (cfam_id -> chip_id etc...)
  */
 
 #include <linux/crc4.h>

@@ -21,6 +26,9 @@
 #include <linux/of.h>
 #include <linux/slab.h>
 #include <linux/bitops.h>
+#include <linux/cdev.h>
+#include <linux/fs.h>
+#include <linux/uaccess.h>
 
 #include "fsi-master.h"
 

@@ -78,8 +86,11 @@ static DEFINE_IDA(master_ida);
 struct fsi_slave {
 	struct device		dev;
 	struct fsi_master	*master;
-	int			id;
-	int			link;
+	struct cdev		cdev;
+	int			cdev_idx;
+	int			id;	/* FSI address */
+	int			link;	/* FSI link# */
+	u32			cfam_id;
 	int			chip_id;
 	uint32_t		size;	/* size of slave address space */
 	u8			t_send_delay;

@@ -607,29 +618,6 @@ static const struct bin_attribute fsi_slave_raw_attr = {
 	.write = fsi_slave_sysfs_raw_write,
 };
 
-static ssize_t fsi_slave_sysfs_term_write(struct file *file,
-		struct kobject *kobj, struct bin_attribute *attr,
-		char *buf, loff_t off, size_t count)
-{
-	struct fsi_slave *slave = to_fsi_slave(kobj_to_dev(kobj));
-	struct fsi_master *master = slave->master;
-
-	if (!master->term)
-		return -ENODEV;
-
-	master->term(master, slave->link, slave->id);
-	return count;
-}
-
-static const struct bin_attribute fsi_slave_term_attr = {
-	.attr = {
-		.name = "term",
-		.mode = 0200,
-	},
-	.size = 0,
-	.write = fsi_slave_sysfs_term_write,
-};
-
 static void fsi_slave_release(struct device *dev)
 {
 	struct fsi_slave *slave = to_fsi_slave(dev);

@@ -682,6 +670,127 @@ static struct device_node *fsi_slave_find_of_node(struct fsi_master *master,
 	return NULL;
 }
 
+static ssize_t cfam_read(struct file *filep, char __user *buf, size_t count,
+			 loff_t *offset)
+{
+	struct fsi_slave *slave = filep->private_data;
+	size_t total_len, read_len;
+	loff_t off = *offset;
+	ssize_t rc;
+
+	if (off < 0)
+		return -EINVAL;
+
+	if (off > 0xffffffff || count > 0xffffffff || off + count > 0xffffffff)
+		return -EINVAL;
+
+	for (total_len = 0; total_len < count; total_len += read_len) {
+		__be32 data;
+
+		read_len = min_t(size_t, count, 4);
+		read_len -= off & 0x3;
+
+		rc = fsi_slave_read(slave, off, &data, read_len);
+		if (rc)
+			goto fail;
+		rc = copy_to_user(buf + total_len, &data, read_len);
+		if (rc) {
+			rc = -EFAULT;
+			goto fail;
+		}
+		off += read_len;
+	}
+	rc = count;
+ fail:
+	*offset = off;
+	return count;
+}
+
+static ssize_t cfam_write(struct file *filep, const char __user *buf,
+			  size_t count, loff_t *offset)
+{
+	struct fsi_slave *slave = filep->private_data;
+	size_t total_len, write_len;
+	loff_t off = *offset;
+	ssize_t rc;
+
+
+	if (off < 0)
+		return -EINVAL;
+
+	if (off > 0xffffffff || count > 0xffffffff || off + count > 0xffffffff)
+		return -EINVAL;
+
+	for (total_len = 0; total_len < count; total_len += write_len) {
+		__be32 data;
+
+		write_len = min_t(size_t, count, 4);
+		write_len -= off & 0x3;
+
+		rc = copy_from_user(&data, buf + total_len, write_len);
+		if (rc) {
+			rc = -EFAULT;
+			goto fail;
+		}
+		rc = fsi_slave_write(slave, off, &data, write_len);
+		if (rc)
+			goto fail;
+		off += write_len;
+	}
+	rc = count;
+ fail:
+	*offset = off;
+	return count;
+}
+
+static loff_t cfam_llseek(struct file *file, loff_t offset, int whence)
+{
+	switch (whence) {
+	case SEEK_CUR:
+		break;
+	case SEEK_SET:
+		file->f_pos = offset;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return offset;
+}
+
+static int cfam_open(struct inode *inode, struct file *file)
+{
+	struct fsi_slave *slave = container_of(inode->i_cdev, struct fsi_slave, cdev);
+
+	file->private_data = slave;
+
+	return 0;
+}
+
+static const struct file_operations cfam_fops = {
+	.owner		= THIS_MODULE,
+	.open		= cfam_open,
+	.llseek		= cfam_llseek,
+	.read		= cfam_read,
+	.write		= cfam_write,
+};
+
+static ssize_t send_term_store(struct device *dev,
+			       struct device_attribute *attr,
+			       const char *buf, size_t count)
+{
+	struct fsi_slave *slave = to_fsi_slave(dev);
+	struct fsi_master *master = slave->master;
+
+	if (!master->term)
+		return -ENODEV;
+
+	master->term(master, slave->link, slave->id);
+	return count;
+}
+
+static DEVICE_ATTR_WO(send_term);
+
 static ssize_t slave_send_echo_show(struct device *dev,
 				    struct device_attribute *attr,
 				    char *buf)

@@ -737,6 +846,52 @@ static ssize_t chip_id_show(struct device *dev,
 
 static DEVICE_ATTR_RO(chip_id);
 
+static ssize_t cfam_id_show(struct device *dev,
+			    struct device_attribute *attr,
+			    char *buf)
+{
+	struct fsi_slave *slave = to_fsi_slave(dev);
+
+	return sprintf(buf, "0x%x\n", slave->cfam_id);
+}
+
+static DEVICE_ATTR_RO(cfam_id);
+
+static struct attribute *cfam_attr[] = {
+	&dev_attr_send_echo_delays.attr,
+	&dev_attr_chip_id.attr,
+	&dev_attr_cfam_id.attr,
+	&dev_attr_send_term.attr,
+	NULL,
+};
+
+static const struct attribute_group cfam_attr_group = {
+	.attrs = cfam_attr,
+};
+
+static const struct attribute_group *cfam_attr_groups[] = {
+	&cfam_attr_group,
+	NULL,
+};
+
+static char *cfam_devnode(struct device *dev, umode_t *mode,
+			  kuid_t *uid, kgid_t *gid)
+{
+	struct fsi_slave *slave = to_fsi_slave(dev);
+
+#ifdef CONFIG_FSI_NEW_DEV_NODE
+	return kasprintf(GFP_KERNEL, "fsi/cfam%d", slave->cdev_idx);
+#else
+	return kasprintf(GFP_KERNEL, "cfam%d", slave->cdev_idx);
+#endif
+}
+
+static const struct device_type cfam_type = {
+	.name = "cfam",
+	.devnode = cfam_devnode,
+	.groups = cfam_attr_groups
+};
+
 static char *fsi_cdev_devnode(struct device *dev, umode_t *mode,
 			      kuid_t *uid, kgid_t *gid)
 {

@@ -808,7 +963,7 @@ EXPORT_SYMBOL_GPL(fsi_free_minor);
 
 static int fsi_slave_init(struct fsi_master *master, int link, uint8_t id)
 {
-	uint32_t chip_id;
+	uint32_t cfam_id;
 	struct fsi_slave *slave;
 	uint8_t crc;
 	__be32 data, llmode;

@@ -826,17 +981,17 @@ static int fsi_slave_init(struct fsi_master *master, int link, uint8_t id)
 				link, id, rc);
 		return -ENODEV;
 	}
-	chip_id = be32_to_cpu(data);
+	cfam_id = be32_to_cpu(data);
 
-	crc = crc4(0, chip_id, 32);
+	crc = crc4(0, cfam_id, 32);
 	if (crc) {
-		dev_warn(&master->dev, "slave %02x:%02x invalid chip id CRC!\n",
+		dev_warn(&master->dev, "slave %02x:%02x invalid cfam id CRC!\n",
 				link, id);
 		return -EIO;
 	}
 
 	dev_dbg(&master->dev, "fsi: found chip %08x at %02x:%02x:%02x\n",
-			chip_id, master->idx, link, id);
+			cfam_id, master->idx, link, id);
 
 	/* If we're behind a master that doesn't provide a self-running bus
 	 * clock, put the slave into async mode

@@ -859,10 +1014,14 @@ static int fsi_slave_init(struct fsi_master *master, int link, uint8_t id)
 	if (!slave)
 		return -ENOMEM;
 
-	slave->master = master;
+	dev_set_name(&slave->dev, "slave@%02x:%02x", link, id);
+	slave->dev.type = &cfam_type;
 	slave->dev.parent = &master->dev;
 	slave->dev.of_node = fsi_slave_find_of_node(master, link, id);
 	slave->dev.release = fsi_slave_release;
+	device_initialize(&slave->dev);
+	slave->cfam_id = cfam_id;
+	slave->master = master;
 	slave->link = link;
 	slave->id = id;
 	slave->size = FSI_SLAVE_SIZE_23b;

@@ -877,6 +1036,21 @@ static int fsi_slave_init(struct fsi_master *master, int link, uint8_t id)
 			slave->chip_id = prop;
 
 	}
+
+	/* Allocate a minor in the FSI space */
+	rc = __fsi_get_new_minor(slave, fsi_dev_cfam, &slave->dev.devt,
+				 &slave->cdev_idx);
+	if (rc)
+		goto err_free;
+
+	/* Create chardev for userspace access */
+	cdev_init(&slave->cdev, &cfam_fops);
+	rc = cdev_device_add(&slave->cdev, &slave->dev);
+	if (rc) {
+		dev_err(&slave->dev, "Error %d creating slave device\n", rc);
+		goto err_free;
+	}
+
 	rc = fsi_slave_set_smode(slave);
 	if (rc) {
 		dev_warn(&master->dev,

@@ -890,30 +1064,11 @@ static int fsi_slave_init(struct fsi_master *master, int link, uint8_t id)
 				    slave->t_send_delay,
 				    slave->t_echo_delay);
 
-	dev_set_name(&slave->dev, "slave@%02x:%02x", link, id);
-	rc = device_register(&slave->dev);
-	if (rc < 0) {
-		dev_warn(&master->dev, "failed to create slave device: %d\n",
-				rc);
-		put_device(&slave->dev);
-		return rc;
-	}
-
+	/* Legacy raw file -> to be removed */
 	rc = device_create_bin_file(&slave->dev, &fsi_slave_raw_attr);
 	if (rc)
 		dev_warn(&slave->dev, "failed to create raw attr: %d\n", rc);
 
-	rc = device_create_bin_file(&slave->dev, &fsi_slave_term_attr);
-	if (rc)
-		dev_warn(&slave->dev, "failed to create term attr: %d\n", rc);
-
-	rc = device_create_file(&slave->dev, &dev_attr_send_echo_delays);
-	if (rc)
-		dev_warn(&slave->dev, "failed to create delay attr: %d\n", rc);
-
-	rc = device_create_file(&slave->dev, &dev_attr_chip_id);
-	if (rc)
-		dev_warn(&slave->dev, "failed to create chip id: %d\n", rc);
 
 	rc = fsi_slave_scan(slave);
 	if (rc)

@@ -921,6 +1076,10 @@ static int fsi_slave_init(struct fsi_master *master, int link, uint8_t id)
 				rc);
 
 	return rc;
+
+ err_free:
+	put_device(&slave->dev);
+	return rc;
 }
 
 /* FSI master support */

@@ -1029,7 +1188,10 @@ static int fsi_slave_remove_device(struct device *dev, void *arg)
 
 static int fsi_master_remove_slave(struct device *dev, void *arg)
 {
+	struct fsi_slave *slave = to_fsi_slave(dev);
+
 	device_for_each_child(dev, NULL, fsi_slave_remove_device);
+	cdev_device_del(&slave->cdev, &slave->dev);
 	put_device(dev);
 	return 0;
 }

index dea5bd48acc5..2c31563fdcae 100644
@@ -1203,8 +1203,14 @@ static void fsi_master_unscan(struct fsi_master *master)
 
 int fsi_master_rescan(struct fsi_master *master)
 {
+	int rc;
+
+	mutex_lock(&master->scan_lock);
 	fsi_master_unscan(master);
-	return fsi_master_scan(master);
+	rc = fsi_master_scan(master);
+	mutex_unlock(&master->scan_lock);
+
+	return rc;
 }
 EXPORT_SYMBOL_GPL(fsi_master_rescan);
 

@@ -1240,6 +1246,7 @@ int fsi_master_register(struct fsi_master *master)
 	int rc;
 	struct device_node *np;
 
+	mutex_init(&master->scan_lock);
 	master->idx = ida_simple_get(&master_ida, 0, INT_MAX, GFP_KERNEL);
 	dev_set_name(&master->dev, "fsi%d", master->idx);
 

@@ -1264,8 +1271,11 @@ int fsi_master_register(struct fsi_master *master)
 	}
 
 	np = dev_of_node(&master->dev);
-	if (!of_property_read_bool(np, "no-scan-on-init"))
+	if (!of_property_read_bool(np, "no-scan-on-init")) {
+		mutex_lock(&master->scan_lock);
 		fsi_master_scan(master);
+		mutex_unlock(&master->scan_lock);
+	}
 
 	return 0;
 }

@@ -1278,7 +1288,9 @@ void fsi_master_unregister(struct fsi_master *master)
 		master->idx = -1;
 	}
 
+	mutex_lock(&master->scan_lock);
 	fsi_master_unscan(master);
+	mutex_unlock(&master->scan_lock);
 	device_unregister(&master->dev);
 }
 EXPORT_SYMBOL_GPL(fsi_master_unregister);

index f653f75da7be..040a7d4cf717 100644
@@ -18,6 +18,7 @@
 #define DRIVERS_FSI_MASTER_H
 
 #include <linux/device.h>
+#include <linux/mutex.h>
 
 /* Various protocol delays */
 #define	FSI_ECHO_DELAY_CLOCKS	16	/* Number clocks for echo delay */

@@ -59,6 +60,7 @@ struct fsi_master {
 	int		idx;
 	int		n_links;
 	int		flags;
+	struct mutex	scan_lock;
 	int		(*read)(struct fsi_master *, int link, uint8_t id,
 				uint32_t addr, void *val, size_t size);
 	int		(*write)(struct fsi_master *, int link, uint8_t id,