[U-Boot,v2,3/5] cmd: Add bind/unbind commands to bind a device to a driver from the command line

In some cases it can be useful to be able to bind a device to a driver from
the command line.
The obvious example is for versatile devices such as USB gadget.
Another use case is when the devices are not yet ready at startup and
require some setup before the drivers are bound (ex: FPGA which bitsream is
fetched from a mass storage or ethernet)

usage example:

bind usb_dev_generic 0 usb_ether
unbind usb_dev_generic 0 usb_ether
or
unbind eth 1

bind /ocp/omap_dwc3@48380000/usb@48390000 usb_ether
unbind /ocp/omap_dwc3@48380000/usb@48390000

Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>

---

Changes in v2:
- Make the bind/unbind command generic, not specific to usb device.
- Update the API to be able to bind/unbind based on DTS node path
- Add a Kconfig option to select the bind/unbind commands

 cmd/Kconfig  |   9 +++
 cmd/Makefile |   1 +
 cmd/bind.c   | 256 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 266 insertions(+)
 create mode 100644 cmd/bind.c

On Mon, Jun 18, 2018 at 8:56 AM, Jean-Jacques Hiblot <jjhiblot@ti.com> wrote:
> In some cases it can be useful to be able to bind a device to a driver from
> the command line.
> The obvious example is for versatile devices such as USB gadget.
> Another use case is when the devices are not yet ready at startup and
> require some setup before the drivers are bound (ex: FPGA which bitsream is
> fetched from a mass storage or ethernet)
>
> usage example:
>
> bind usb_dev_generic 0 usb_ether
> unbind usb_dev_generic 0 usb_ether
> or
> unbind eth 1
>
> bind /ocp/omap_dwc3@48380000/usb@48390000 usb_ether
> unbind /ocp/omap_dwc3@48380000/usb@48390000
>
> Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>
>

Looks great!

Reviewed-by: Joe Hershberger <joe.hershberger@ni.com>

Hi Jean-Jacques,

On 18 June 2018 at 07:56, Jean-Jacques Hiblot <jjhiblot@ti.com> wrote:
> In some cases it can be useful to be able to bind a device to a driver from
> the command line.
> The obvious example is for versatile devices such as USB gadget.
> Another use case is when the devices are not yet ready at startup and
> require some setup before the drivers are bound (ex: FPGA which bitsream is
> fetched from a mass storage or ethernet)
>
> usage example:
>
> bind usb_dev_generic 0 usb_ether
> unbind usb_dev_generic 0 usb_ether
> or
> unbind eth 1
>
> bind /ocp/omap_dwc3@48380000/usb@48390000 usb_ether
> unbind /ocp/omap_dwc3@48380000/usb@48390000
>
> Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>
>
> ---
>
> Changes in v2:
> - Make the bind/unbind command generic, not specific to usb device.
> - Update the API to be able to bind/unbind based on DTS node path
> - Add a Kconfig option to select the bind/unbind commands
>
>  cmd/Kconfig  |   9 +++
>  cmd/Makefile |   1 +
>  cmd/bind.c   | 256 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 266 insertions(+)
>  create mode 100644 cmd/bind.c

This looks good to me, with a few comments below. I think it is great
to get this sort of functionality in U-Boot.

Please can you add a test which calls issues a few of these commands?
You might find test_shell_basics.py useful as a starting point.

>
> diff --git a/cmd/Kconfig b/cmd/Kconfig
> index 1eb55e5..d6bbfba 100644
> --- a/cmd/Kconfig
> +++ b/cmd/Kconfig
> @@ -607,6 +607,15 @@ config CMD_ADC
>           Shows ADC device info and permit printing one-shot analog converted
>           data from a named Analog to Digital Converter.
>
> +config CMD_BIND
> +       bool "bind/unbind - Bind or unbind a device to/from a driver"
> +       depends on DM
> +       help
> +         Bind or unbind a device to/from a driver from the command line.
> +         This is useful in situations where a device may be handled by several
> +         drivers. For example, this can be used to bind a UDC to the usb ether
> +         gadget driver from the command line.
> +
>  config CMD_CLK
>         bool "clk - Show clock frequencies"
>         help
> diff --git a/cmd/Makefile b/cmd/Makefile
> index e0088df..b12aca3 100644
> --- a/cmd/Makefile
> +++ b/cmd/Makefile
> @@ -19,6 +19,7 @@ obj-$(CONFIG_SOURCE) += source.o
>  obj-$(CONFIG_CMD_SOURCE) += source.o
>  obj-$(CONFIG_CMD_BDI) += bdinfo.o
>  obj-$(CONFIG_CMD_BEDBUG) += bedbug.o
> +obj-$(CONFIG_CMD_BIND) += bind.o
>  obj-$(CONFIG_CMD_BINOP) += binop.o
>  obj-$(CONFIG_CMD_BLOCK_CACHE) += blkcache.o
>  obj-$(CONFIG_CMD_BMP) += bmp.o
> diff --git a/cmd/bind.c b/cmd/bind.c
> new file mode 100644
> index 0000000..60d84d6
> --- /dev/null
> +++ b/cmd/bind.c
> @@ -0,0 +1,256 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Copyright (c) 2018 JJ Hiblot <jjhiblot@ti.com>
> + */
> +
> +#include <common.h>
> +#include <dm.h>
> +#include <dm/device-internal.h>
> +#include <dm/lists.h>
> +#include <dm/uclass-internal.h>
> +
> +static int bind_by_class_index(const char *uclass, int index,
> +                              const char *drv_name)
> +{
> +       static enum uclass_id uclass_id;
> +       struct udevice *dev;
> +       struct udevice *parent;
> +       int ret;
> +       struct driver *drv;
> +
> +       drv = lists_driver_lookup_name(drv_name);
> +       if (!drv) {
> +               printf("Cannot find driver '%s'\n", drv_name);
> +               return -ENOENT;
> +       }
> +
> +       uclass_id = uclass_get_by_name(uclass);
> +       if (uclass_id == UCLASS_INVALID) {
> +               printf("%s is not a valid uclass\n", uclass);
> +               return -EINVAL;
> +       }
> +
> +       ret = uclass_find_device(uclass_id, index, &parent);
> +       if (!parent || ret) {
> +               printf("Cannot find device %d of class %s\n", index, uclass);
> +               return ret;
> +       }
> +
> +       ret = device_bind_with_driver_data(parent, drv, drv->name, 0,
> +                                          ofnode_null(), &dev);
> +       if (!dev || ret) {
> +               printf("Unable to bind. err:%d\n", ret);
> +               return ret;
> +       }
> +
> +       return 0;
> +}
> +
> +static int unbind_by_class_index(const char *uclass, int index)
> +{
> +       static enum uclass_id uclass_id;
> +       struct udevice *dev;
> +       int ret;
> +
> +       uclass_id = uclass_get_by_name(uclass);
> +       if (uclass_id == UCLASS_INVALID) {
> +               printf("%s is not a valid uclass\n", uclass);
> +               return -EINVAL;
> +       }
> +
> +       ret = uclass_find_device(uclass_id, index, &dev);
> +       if (!dev || ret) {
> +               printf("Cannot find device %d of class %s\n", index, uclass);
> +               return ret;
> +       }
> +
> +       ret = device_unbind(dev);
> +       if (ret) {
> +               printf("Unable to unbind. err:%d\n", ret);
> +               return ret;
> +       }
> +
> +       return 0;
> +}
> +
> +static int unbind_child_by_class_index(const char *uclass, int index,
> +                                      const char *drv_name)
> +{
> +       static enum uclass_id uclass_id;
> +       struct udevice *parent;
> +       struct udevice *dev, *n;
> +       int ret;
> +       struct driver *drv;
> +
> +       drv = lists_driver_lookup_name(drv_name);
> +       if (!drv) {
> +               printf("Cannot find driver '%s'\n", drv_name);
> +               return -ENOENT;
> +       }
> +
> +       uclass_id = uclass_get_by_name(uclass);
> +       if (uclass_id == UCLASS_INVALID) {
> +               printf("%s is not a valid uclass\n", uclass);
> +               return -EINVAL;
> +       }
> +
> +       ret = uclass_find_device(uclass_id, index, &parent);
> +       if (!parent || ret) {
> +               printf("Cannot find device %d of class %s\n", index, uclass);
> +               return ret;
> +       }

The above two blocks duplicate code in the function above. Can you put
then in a separate function can call it here?

> +
> +       list_for_each_entry_safe(dev, n, &parent->child_head, sibling_node) {

This feels like code that should be in drivers/core since it is
messing with the internal lists and driver names. But I suppose for
now we can keep it here. Let's see how things expand later.

> +               int rc;
> +
> +               if (dev->driver != drv)
> +                       continue;
> +
> +               rc = device_unbind(dev);
> +               if (rc && !ret) {
> +                       printf("failed to unbind %s/%s\n", dev->name,
> +                              drv->name);
> +                       ret = rc;
> +               }
> +       }
> +
> +       return ret;
> +}
> +
> +static int bind_by_node_path(const char *path, const char *drv_name)
> +{
> +       struct udevice *dev;
> +       struct udevice *parent = NULL;
> +       int ret;
> +       int id;
> +       ofnode ofnode;
> +       struct driver *drv;
> +
> +       drv = lists_driver_lookup_name(drv_name);
> +       if (!drv) {
> +               printf("%s is not a valid driver name\n", drv_name);
> +               return -ENOENT;
> +       }
> +
> +       ofnode = ofnode_path(path);
> +       if (!ofnode_valid(ofnode)) {
> +               printf("%s is not a valid node path\n", path);
> +               return -EINVAL;
> +       }
> +
> +       while (ofnode_valid(ofnode)) {
> +               for (id = 0; id < UCLASS_COUNT; id++) {
> +                       if (!uclass_find_device_by_ofnode(id, ofnode, &parent))
> +                               break;
> +               }

Can you create a function in drivers/core that finds an ofnode
globally? I don't like having this logic here.

You could convert device_get_global_by_of_offset() to use an ofnode.

Remember that any printf() calls should be here, not in drivers/core.

> +               if (parent)
> +                       break;
> +               ofnode = ofnode_get_parent(ofnode);
> +       }
> +
> +       if (!parent) {
> +               printf("Cannot find a parent device for node path %s\n", path);
> +               return -ENODEV;
> +       }
> +
> +       ret = device_bind_with_driver_data(parent, drv, drv->name, 0,
> +                                          ofnode_path(path), &dev);
> +       if (!dev || ret) {
> +               printf("Unable to bind. err:%d\n", ret);
> +               return ret;
> +       }
> +
> +       return 0;
> +}
> +
> +static int unbind_by_node_path(const char *path)
> +{
> +       struct udevice *dev;
> +       int ret;
> +       int id;
> +       ofnode ofnode;
> +
> +       ofnode = ofnode_path(path);
> +       if (!ofnode_valid(ofnode)) {
> +               printf("%s is not a valid node path\n", path);
> +               return -EINVAL;
> +       }
> +
> +       for (id = 0; id < UCLASS_COUNT; id++) {
> +               if (uclass_find_device_by_ofnode(id, ofnode, &dev) == 0)
> +                       break;
> +       }

Same comment as above - move this logic to drivers/core

> +
> +       if (!dev) {
> +               printf("Cannot find a device with path %s\n", path);
> +               return -ENODEV;
> +       }
> +
> +       ret = device_unbind(dev);
> +       if (ret) {
> +               printf("Unable to unbind. err:%d\n", ret);
> +               return ret;
> +       }
> +
> +       return 0;
> +}
> +
> +static int do_bind_unbind(cmd_tbl_t *cmdtp, int flag, int argc,
> +                         char * const argv[])
> +{
> +       int ret;
> +       bool bind;
> +       bool by_node;
> +
> +       if (argc < 2)
> +               return CMD_RET_USAGE;
> +
> +       bind = (argv[0][0] == 'b');
> +       by_node = (argv[1][0] == '/');
> +
> +       if (by_node && bind) {
> +               if (argc != 3)
> +                       return CMD_RET_USAGE;
> +               ret = bind_by_node_path(argv[1], argv[2]);
> +       } else if (by_node && !bind) {
> +               if (argc != 2)
> +                       return CMD_RET_USAGE;
> +               ret = unbind_by_node_path(argv[1]);
> +       } else if (!by_node && bind) {
> +               int index = (argc > 2) ? simple_strtoul(argv[2], NULL, 10) : 0;
> +
> +               if (argc != 4)
> +                       return CMD_RET_USAGE;
> +               ret = bind_by_class_index(argv[1], index, argv[3]);
> +       } else if (!by_node && !bind) {
> +               int index = (argc > 2) ? simple_strtoul(argv[2], NULL, 10) : 0;
> +
> +               if (argc == 3)
> +                       ret = unbind_by_class_index(argv[1], index);
> +               else if (argc == 4)
> +                       ret = unbind_child_by_class_index(argv[1], index,
> +                                                         argv[3]);
> +               else
> +                       return CMD_RET_USAGE;
> +       }
> +
> +       if (ret)
> +               return CMD_RET_FAILURE;
> +       else
> +               return CMD_RET_SUCCESS;
> +}
> +
> +U_BOOT_CMD(
> +       bind,   4,      0,      do_bind_unbind,
> +       "Bind a device to a driver",
> +       "<node path> <driver>\n"
> +       "bind <class> <index> <driver>\n"
> +);
> +
> +U_BOOT_CMD(
> +       unbind, 4,      0,      do_bind_unbind,
> +       "Unbind a device from a driver",
> +       "<node path>\n"
> +       "unbind <class> <index>\n"
> +       "unbind <class> <index> <driver>\n"
> +);
> --
> 2.7.4
>

Regards,
Simon

On 18.6.2018 15:56, Jean-Jacques Hiblot wrote:
> In some cases it can be useful to be able to bind a device to a driver from
> the command line.
> The obvious example is for versatile devices such as USB gadget.
> Another use case is when the devices are not yet ready at startup and
> require some setup before the drivers are bound (ex: FPGA which bitsream is
> fetched from a mass storage or ethernet)
> 
> usage example:
> 
> bind usb_dev_generic 0 usb_ether
> unbind usb_dev_generic 0 usb_ether
> or
> unbind eth 1
> 
> bind /ocp/omap_dwc3@48380000/usb@48390000 usb_ether
> unbind /ocp/omap_dwc3@48380000/usb@48390000
> 
> Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>
> 
> ---
> 
> Changes in v2:
> - Make the bind/unbind command generic, not specific to usb device.
> - Update the API to be able to bind/unbind based on DTS node path
> - Add a Kconfig option to select the bind/unbind commands
> 
>  cmd/Kconfig  |   9 +++
>  cmd/Makefile |   1 +
>  cmd/bind.c   | 256 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 266 insertions(+)
>  create mode 100644 cmd/bind.c
> 
> diff --git a/cmd/Kconfig b/cmd/Kconfig
> index 1eb55e5..d6bbfba 100644
> --- a/cmd/Kconfig
> +++ b/cmd/Kconfig
> @@ -607,6 +607,15 @@ config CMD_ADC
>  	  Shows ADC device info and permit printing one-shot analog converted
>  	  data from a named Analog to Digital Converter.
>  
> +config CMD_BIND
> +	bool "bind/unbind - Bind or unbind a device to/from a driver"
> +	depends on DM
> +	help
> +	  Bind or unbind a device to/from a driver from the command line.
> +	  This is useful in situations where a device may be handled by several
> +	  drivers. For example, this can be used to bind a UDC to the usb ether
> +	  gadget driver from the command line.
> +
>  config CMD_CLK
>  	bool "clk - Show clock frequencies"
>  	help
> diff --git a/cmd/Makefile b/cmd/Makefile
> index e0088df..b12aca3 100644
> --- a/cmd/Makefile
> +++ b/cmd/Makefile
> @@ -19,6 +19,7 @@ obj-$(CONFIG_SOURCE) += source.o
>  obj-$(CONFIG_CMD_SOURCE) += source.o
>  obj-$(CONFIG_CMD_BDI) += bdinfo.o
>  obj-$(CONFIG_CMD_BEDBUG) += bedbug.o
> +obj-$(CONFIG_CMD_BIND) += bind.o
>  obj-$(CONFIG_CMD_BINOP) += binop.o
>  obj-$(CONFIG_CMD_BLOCK_CACHE) += blkcache.o
>  obj-$(CONFIG_CMD_BMP) += bmp.o
> diff --git a/cmd/bind.c b/cmd/bind.c
> new file mode 100644
> index 0000000..60d84d6
> --- /dev/null
> +++ b/cmd/bind.c
> @@ -0,0 +1,256 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Copyright (c) 2018 JJ Hiblot <jjhiblot@ti.com>
> + */
> +
> +#include <common.h>
> +#include <dm.h>
> +#include <dm/device-internal.h>
> +#include <dm/lists.h>
> +#include <dm/uclass-internal.h>
> +
> +static int bind_by_class_index(const char *uclass, int index,
> +			       const char *drv_name)
> +{
> +	static enum uclass_id uclass_id;
> +	struct udevice *dev;
> +	struct udevice *parent;
> +	int ret;
> +	struct driver *drv;
> +
> +	drv = lists_driver_lookup_name(drv_name);
> +	if (!drv) {
> +		printf("Cannot find driver '%s'\n", drv_name);
> +		return -ENOENT;
> +	}
> +
> +	uclass_id = uclass_get_by_name(uclass);
> +	if (uclass_id == UCLASS_INVALID) {
> +		printf("%s is not a valid uclass\n", uclass);
> +		return -EINVAL;
> +	}
> +
> +	ret = uclass_find_device(uclass_id, index, &parent);
> +	if (!parent || ret) {
> +		printf("Cannot find device %d of class %s\n", index, uclass);
> +		return ret;
> +	}
> +
> +	ret = device_bind_with_driver_data(parent, drv, drv->name, 0,
> +					   ofnode_null(), &dev);
> +	if (!dev || ret) {
> +		printf("Unable to bind. err:%d\n", ret);
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static int unbind_by_class_index(const char *uclass, int index)
> +{
> +	static enum uclass_id uclass_id;
> +	struct udevice *dev;
> +	int ret;
> +
> +	uclass_id = uclass_get_by_name(uclass);
> +	if (uclass_id == UCLASS_INVALID) {
> +		printf("%s is not a valid uclass\n", uclass);
> +		return -EINVAL;
> +	}
> +
> +	ret = uclass_find_device(uclass_id, index, &dev);
> +	if (!dev || ret) {
> +		printf("Cannot find device %d of class %s\n", index, uclass);
> +		return ret;
> +	}
> +
> +	ret = device_unbind(dev);
> +	if (ret) {
> +		printf("Unable to unbind. err:%d\n", ret);
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static int unbind_child_by_class_index(const char *uclass, int index,
> +				       const char *drv_name)
> +{
> +	static enum uclass_id uclass_id;
> +	struct udevice *parent;
> +	struct udevice *dev, *n;
> +	int ret;
> +	struct driver *drv;
> +
> +	drv = lists_driver_lookup_name(drv_name);
> +	if (!drv) {
> +		printf("Cannot find driver '%s'\n", drv_name);
> +		return -ENOENT;
> +	}
> +
> +	uclass_id = uclass_get_by_name(uclass);
> +	if (uclass_id == UCLASS_INVALID) {
> +		printf("%s is not a valid uclass\n", uclass);
> +		return -EINVAL;
> +	}
> +
> +	ret = uclass_find_device(uclass_id, index, &parent);
> +	if (!parent || ret) {
> +		printf("Cannot find device %d of class %s\n", index, uclass);
> +		return ret;
> +	}
> +
> +	list_for_each_entry_safe(dev, n, &parent->child_head, sibling_node) {
> +		int rc;
> +
> +		if (dev->driver != drv)
> +			continue;
> +
> +		rc = device_unbind(dev);
> +		if (rc && !ret) {
> +			printf("failed to unbind %s/%s\n", dev->name,
> +			       drv->name);
> +			ret = rc;
> +		}
> +	}
> +
> +	return ret;
> +}
> +
> +static int bind_by_node_path(const char *path, const char *drv_name)
> +{
> +	struct udevice *dev;
> +	struct udevice *parent = NULL;
> +	int ret;
> +	int id;
> +	ofnode ofnode;
> +	struct driver *drv;
> +
> +	drv = lists_driver_lookup_name(drv_name);
> +	if (!drv) {
> +		printf("%s is not a valid driver name\n", drv_name);
> +		return -ENOENT;
> +	}
> +
> +	ofnode = ofnode_path(path);
> +	if (!ofnode_valid(ofnode)) {
> +		printf("%s is not a valid node path\n", path);
> +		return -EINVAL;
> +	}
> +
> +	while (ofnode_valid(ofnode)) {
> +		for (id = 0; id < UCLASS_COUNT; id++) {
> +			if (!uclass_find_device_by_ofnode(id, ofnode, &parent))
> +				break;
> +		}
> +		if (parent)
> +			break;
> +		ofnode = ofnode_get_parent(ofnode);
> +	}
> +
> +	if (!parent) {
> +		printf("Cannot find a parent device for node path %s\n", path);
> +		return -ENODEV;
> +	}
> +
> +	ret = device_bind_with_driver_data(parent, drv, drv->name, 0,
> +					   ofnode_path(path), &dev);
> +	if (!dev || ret) {
> +		printf("Unable to bind. err:%d\n", ret);
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static int unbind_by_node_path(const char *path)
> +{
> +	struct udevice *dev;
> +	int ret;
> +	int id;
> +	ofnode ofnode;
> +
> +	ofnode = ofnode_path(path);
> +	if (!ofnode_valid(ofnode)) {
> +		printf("%s is not a valid node path\n", path);
> +		return -EINVAL;
> +	}
> +
> +	for (id = 0; id < UCLASS_COUNT; id++) {
> +		if (uclass_find_device_by_ofnode(id, ofnode, &dev) == 0)
> +			break;
> +	}
> +
> +	if (!dev) {
> +		printf("Cannot find a device with path %s\n", path);
> +		return -ENODEV;
> +	}
> +
> +	ret = device_unbind(dev);
> +	if (ret) {
> +		printf("Unable to unbind. err:%d\n", ret);
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static int do_bind_unbind(cmd_tbl_t *cmdtp, int flag, int argc,
> +			  char * const argv[])
> +{
> +	int ret;
> +	bool bind;
> +	bool by_node;
> +
> +	if (argc < 2)
> +		return CMD_RET_USAGE;
> +
> +	bind = (argv[0][0] == 'b');
> +	by_node = (argv[1][0] == '/');
> +
> +	if (by_node && bind) {
> +		if (argc != 3)
> +			return CMD_RET_USAGE;
> +		ret = bind_by_node_path(argv[1], argv[2]);
> +	} else if (by_node && !bind) {
> +		if (argc != 2)
> +			return CMD_RET_USAGE;
> +		ret = unbind_by_node_path(argv[1]);
> +	} else if (!by_node && bind) {
> +		int index = (argc > 2) ? simple_strtoul(argv[2], NULL, 10) : 0;
> +
> +		if (argc != 4)
> +			return CMD_RET_USAGE;
> +		ret = bind_by_class_index(argv[1], index, argv[3]);
> +	} else if (!by_node && !bind) {
> +		int index = (argc > 2) ? simple_strtoul(argv[2], NULL, 10) : 0;
> +
> +		if (argc == 3)
> +			ret = unbind_by_class_index(argv[1], index);
> +		else if (argc == 4)
> +			ret = unbind_child_by_class_index(argv[1], index,
> +							  argv[3]);
> +		else
> +			return CMD_RET_USAGE;
> +	}
> +
> +	if (ret)
> +		return CMD_RET_FAILURE;
> +	else
> +		return CMD_RET_SUCCESS;

I am getting compilation warnings bout this ret handling.

cmd/bind.c: In function ‘do_bind_unbind’:
cmd/bind.c:237:5: warning: ‘ret’ may be used uninitialized in this
function [-Wmaybe-uninitialized]
  if (ret)
     ^



> +}
> +
> +U_BOOT_CMD(
> +	bind,	4,	0,	do_bind_unbind,
> +	"Bind a device to a driver",
> +	"<node path> <driver>\n"
> +	"bind <class> <index> <driver>\n"
> +);
> +
> +U_BOOT_CMD(
> +	unbind,	4,	0,	do_bind_unbind,
> +	"Unbind a device from a driver",
> +	"<node path>\n"
> +	"unbind <class> <index>\n"
> +	"unbind <class> <index> <driver>\n"
> +);
> 

I have played with this series with zynq_gpio driver on zcu100.
It can be only one instance of this driver but I can call bind multiple
times and instance is listed with new index. Log below.

ZynqMP> dm tree
 Class    index  Probed  Driver      Name
-----------------------------------------
 root        0  [ + ]   root_drive  root_driver
 serial      0  [   ]   arm_dcc     |-- dcc
 simple_bus  0  [   ]   generic_si  |-- amba_apu@0
 simple_bus  1  [ + ]   generic_si  |-- amba
 gpio        0  [   ]   gpio_zynq   |   |-- gpio@ff0a0000
 mmc         0  [ + ]   arasan_sdh  |   |-- sdhci@ff160000
...
ZynqMP> bind /amba/gpio@ff0a0000 gpio_zynq
EFI: Initializing UCLASS_EFI
Calling zynq_gpio_bind
ZynqMP> dm tree
 Class    index  Probed  Driver      Name
-----------------------------------------
 root        0  [ + ]   root_drive  root_driver
 serial      0  [   ]   arm_dcc     |-- dcc
 simple_bus  0  [   ]   generic_si  |-- amba_apu@0
 simple_bus  1  [ + ]   generic_si  |-- amba
 gpio        0  [   ]   gpio_zynq   |   |-- gpio@ff0a0000
 gpio        1  [   ]   gpio_zynq   |   |   `-- gpio_zynq
 mmc         0  [ + ]   arasan_sdh  |   |-- sdhci@ff160000
...
ZynqMP>

I can read dev->seq in probe and fail if dev->seq is not 0 but not sure
if this should be checked in probe.

The second thing is that when I call unbind for probed device that it is
failing because it hasn't been removed.

ZynqMP> dm tree
 Class    index  Probed  Driver      Name
-----------------------------------------
 root        0  [ + ]   root_drive  root_driver
 serial      0  [   ]   arm_dcc     |-- dcc
 simple_bus  0  [   ]   generic_si  |-- amba_apu@0
 simple_bus  1  [ + ]   generic_si  |-- amba
 gpio        0  [   ]   gpio_zynq   |   |-- gpio@ff0a0000
 mmc         0  [ + ]   arasan_sdh  |   |-- sdhci@ff160000
...
ZynqMP> gpio status 0
Calling zynq_gpio_ofdata_to_platdata
Calling zynq_gpio_probe 0
ZynqMP> dm tree
 Class    index  Probed  Driver      Name
-----------------------------------------
 root        0  [ + ]   root_drive  root_driver
 serial      0  [   ]   arm_dcc     |-- dcc
 simple_bus  0  [   ]   generic_si  |-- amba_apu@0
 simple_bus  1  [ + ]   generic_si  |-- amba
 gpio        0  [ + ]   gpio_zynq   |   |-- gpio@ff0a0000
 mmc         0  [ + ]   arasan_sdh  |   |-- sdhci@ff160000
...
ZynqMP> unbind /amba/gpio@ff0a0000
EFI: Initializing UCLASS_EFI
activated
Unable to unbind. err:-22

That's why I am curious if this command enable to unbind device then
there should be also an option to remove that device too.

More generic note. I have been taking information about structure from
dm tree command and I would consider to move test/dm/cmd_dm.c to cmd
folder and extend this file by these new functionality.

Thanks,
Michal