[PATCHv3,2/4] wiegand: add Wiegand bus driver
Commit Message
Add a bus driver for Wiegand protocol. The bus driver handles
Wiegand controller and Wiegand device managemement and driver
matching. The bus driver defines the structures for Wiegand
controllers and Wiegand devices.
Wiegand controller structure represents a master and contains
attributes such as the payload_len for configuring the size
of a single Wiegand message in bits. It also stores the
controller attributes defined in the devicetree.
Each Wiegand controller should be associated with one Wiegand
device, as Wiegand is typically a point-to-point bus.
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Martin Zaťovič <m.zatovic1@gmail.com>
---
MAINTAINERS | 2 +
drivers/Kconfig | 2 +
drivers/Makefile | 1 +
drivers/wiegand/Kconfig | 20 ++
drivers/wiegand/Makefile | 1 +
drivers/wiegand/wiegand.c | 500 ++++++++++++++++++++++++++++++++++++++
include/linux/wiegand.h | 155 ++++++++++++
7 files changed, 681 insertions(+)
create mode 100644 drivers/wiegand/Kconfig
create mode 100644 drivers/wiegand/Makefile
create mode 100644 drivers/wiegand/wiegand.c
create mode 100644 include/linux/wiegand.h
Comments
On Wed, Mar 01, 2023 at 03:28:33PM +0100, Martin Zaťovič wrote:
> Add a bus driver for Wiegand protocol. The bus driver handles
> Wiegand controller and Wiegand device managemement and driver
> matching. The bus driver defines the structures for Wiegand
> controllers and Wiegand devices.
>
> Wiegand controller structure represents a master and contains
> attributes such as the payload_len for configuring the size
> of a single Wiegand message in bits. It also stores the
> controller attributes defined in the devicetree.
>
> Each Wiegand controller should be associated with one Wiegand
> device, as Wiegand is typically a point-to-point bus.
...
> +#include <linux/device.h>
> +#include <linux/dmaengine.h>
> +#include <linux/dma-mapping.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_device.h>
> +#include <linux/property.h>
> +#include <linux/slab.h>
> +#include <linux/wiegand.h>
> +
> +static struct bus_type wiegand_bus_type;
> +static DEFINE_IDR(wiegand_controller_idr);
Why not IDA or even xarray?
...
> +static DEFINE_MUTEX(board_lock);
Or locks need a good description for what they are.
...
> +static void devm_wiegand_release_controller(struct device *dev, void *ctlr)
> +{
> + wiegand_controller_put(*(struct wiegand_controller **)ctlr);
> +}
This is not used in the following function, so can be moved closer to its user.
...
> +struct wiegand_controller *devm_wiegand_alloc_controller(struct device *dev, unsigned int size,
> + bool slave)
> +{
> + struct wiegand_controller **ptr, *ctlr;
> +
> + ptr = devres_alloc(devm_wiegand_release_controller, sizeof(*ptr), GFP_KERNEL);
> + if (!ptr)
> + return NULL;
> +
> + ctlr = wiegand_alloc_controller(dev, size, slave);
> + if (ctlr) {
> + ctlr->devm_allocated = true;
> + *ptr = ctlr;
> + devres_add(dev, ptr);
> + } else {
> + devres_free(ptr);
> + }
> +
> + return ctlr;
Can this utilize devm_add_action_or_reset()?
> +}
...
> +/**
> + * of_register_wiegand_device - allocates and registers a new Wiegand device based on devicetree
NAK for OF only code. New, esp. bus, code must be agnostic. We have all means
for that.
register_wiegand_device() or similar name.
> + * node
> + * @ctlr: controller structure to attach device to
> + * @nc: devicetree node for the device
> + */
> +static struct wiegand_device *of_register_wiegand_device(struct wiegand_controller *ctlr,
Ditto.
> + struct device_node *nc)
struct fwnode_handle *fwnode
> +{
> + struct wiegand_device *wiegand;
> + int rc;
> +
> + wiegand = wiegand_alloc_device(ctlr);
> + if (!wiegand) {
> + dev_err(&ctlr->dev, "wiegad_device alloc error for %pOF\n", nc);
> + rc = -ENOMEM;
> + goto err_out;
> + }
> + of_node_get(nc);
> + wiegand->dev.of_node = nc;
> + wiegand->dev.fwnode = of_fwnode_handle(nc);
device_set_node(&wiegand->dev, fwnode_handle_get(fwnode));
> + rc = wiegand_add_device(wiegand);
> + if (rc) {
> + dev_err(&ctlr->dev, "wiegand_device register error %pOF\n", nc);
> + goto err_of_node_put;
> + }
> +
> + /* check if more devices are connected to the bus */
> + if (ctlr->device_count > 1)
> + dev_warn(&ctlr->dev, "Wiegand is a point-to-point bus, it is advised to only connect one device per Wiegand bus. The devices may not communicate using the same pulse length, format or else.\n");
> +
> + return wiegand;
> +
> +err_of_node_put:
> + of_node_put(nc);
> +err_out:
> + wiegand_dev_put(wiegand);
> + return ERR_PTR(rc);
> +}
> +
> +/**
> + * of_register_wiegand_devices - creates a wiegand device for all children of a controller
> + * devicetree node
> + * @ctlr: controller structure to check
> + */
> +static void of_register_wiegand_devices(struct wiegand_controller *ctlr)
> +{
> + struct wiegand_device *wiegand;
> + struct device_node *nc;
> +
> + if (!ctlr->dev.of_node)
> + return;
> +
> + for_each_available_child_of_node(ctlr->dev.of_node, nc) {
> + if (of_node_test_and_set_flag(nc, OF_POPULATED))
> + continue;
> + wiegand = of_register_wiegand_device(ctlr, nc);
> + if (IS_ERR(wiegand)) {
> + dev_warn(&ctlr->dev, "Failed to create wiegand device for %pOF\n", nc);
> + of_node_clear_flag(nc, OF_POPULATED);
> + }
> + }
No way. Use agnostic approach. See above for some suggestions.
> +}
...
> + if (!dev)
> + return -ENODEV;
When is it true and why is it a problem?
> + if (ctlr->dev.of_node) {
> + id = of_alias_get_id(ctlr->dev.of_node, "wiegand");
Why? What does this bring to us and why it's so important?
> + if (id > 0) {
> + ctlr->bus_num = id;
> + mutex_lock(&board_lock);
> + id = idr_alloc(&wiegand_controller_idr, ctlr, ctlr->bus_num,
> + ctlr->bus_num + 1, GFP_KERNEL);
> + mutex_unlock(&board_lock);
> + if (WARN(id < 0, "couldn't get idr"))
> + return id == -ENOSPC ? -EBUSY : id;
Why rewriting error code?
> + }
> + device_property_read_u32(&ctlr->dev, "pulse-len-us", &ctlr->pulse_len);
> + device_property_read_u32(&ctlr->dev, "interval-len-us", &ctlr->interval_len);
> + device_property_read_u32(&ctlr->dev, "frame-gap-us", &ctlr->frame_gap);
> + }
> + if (ctlr->bus_num < 0) {
> + first_dynamic = of_alias_get_highest_id("wiegand");
> + if (first_dynamic < 0)
> + first_dynamic = 0;
> + else
> + first_dynamic++;
> +
> + mutex_lock(&board_lock);
> + id = idr_alloc(&wiegand_controller_idr, ctlr, first_dynamic,
> + 0, GFP_KERNEL);
> + mutex_unlock(&board_lock);
> + if (WARN(id < 0, "couldn't get idr\n"))
> + return id;
> + ctlr->bus_num = id;
> + }
> +
> + if (ctlr->pulse_len == 0) {
> + dev_warn(&ctlr->dev, "pulse_len is not initialized, setting the default value 50us\n");
> + ctlr->pulse_len = 50;
> + }
> + if (ctlr->interval_len == 0) {
> + dev_warn(&ctlr->dev, "interval_len is not initialized, setting the default value 2000us\n");
> + ctlr->interval_len = 2000;
> + }
> + if (ctlr->frame_gap == 0) {
> + dev_warn(&ctlr->dev, "frame_gap is not initialized, setting the default value 2000us\n");
> + ctlr->frame_gap = 2000;
> + }
Why warnings? Can't it survive without them? (See, for example, how I²C
controllers get timings).
> + dev_set_name(&ctlr->dev, "wiegand%u", ctlr->bus_num);
> + ctlr->device_count = 0;
> +
> + status = device_add(&ctlr->dev);
> + if (status < 0)
> + goto free_bus_id;
> +
> + of_register_wiegand_devices(ctlr);
> +
> + return status;
> +
> +free_bus_id:
> + mutex_lock(&board_lock);
> + idr_remove(&wiegand_controller_idr, ctlr->bus_num);
> + mutex_unlock(&board_lock);
> + return status;
> +}
...
> +int devm_wiegand_register_controller(struct device *dev, struct wiegand_controller *ctlr)
> +{
> + struct wiegand_controller **ptr;
> + int ret;
> +
> + ptr = devres_alloc(devm_wiegand_unregister, sizeof(*ptr), GFP_KERNEL);
> + if (!ptr)
> + return -ENOMEM;
> +
> + ret = wiegand_register_controller(ctlr);
> + if (!ret) {
> + *ptr = ctlr;
> + devres_add(dev, ptr);
> + } else {
> + devres_free(ptr);
> + }
devm_add_action_or_reset() ?
> + return ret;
> +}
...
> +struct wiegand_device *wiegand_alloc_device(struct wiegand_controller *ctlr)
> +{
> + struct wiegand_device *wiegand;
> +
> + if (!wiegand_controller_get(ctlr))
> + return NULL;
Is it important to be called before pure memory allocation? The reference
counting on the existing resource is less failure prone, right?
> + wiegand = kzalloc(sizeof(*wiegand), GFP_KERNEL);
> + if (!wiegand) {
> + wiegand_controller_put(ctlr);
> + return NULL;
> + }
> +
> + wiegand->controller = ctlr;
> + wiegand->dev.parent = &ctlr->dev;
> + wiegand->dev.bus = &wiegand_bus_type;
> + wiegand->dev.release = wieganddev_release;
> +
> + device_initialize(&wiegand->dev);
> + return wiegand;
> +}
...
> +static void wiegand_dev_set_name(struct wiegand_device *wiegand, u8 id)
> +{
> + dev_set_name(&wiegand->dev, "%s.%u", dev_name(&wiegand->controller->dev), id);
Why error is ignored?
> +}
...
> + if (wiegand->dev.of_node) {
> + of_node_clear_flag(wiegand->dev.of_node, OF_POPULATED);
> + of_node_put(wiegand->dev.of_node);
> + }
fwnode APIs, please.
...
> +static int wiegand_probe(struct device *dev)
> +{
> + struct wiegand_device *wiegand = to_wiegand_device(dev);
> + const struct wiegand_driver *wdrv = to_wiegand_driver(dev->driver);
> + int ret = 0;
> +
> + if (wdrv->probe)
> + ret = wdrv->probe(wiegand);
> +
> + return ret;
Hmm... this is just
if (wdrv->probe)
return wdrv->probe(wiegand);
return 0;
> +}
...
> + if (wdrv->driver.of_match_table) {
> + const struct of_device_id *of_id;
> +
> + for (of_id = wdrv->driver.of_match_table; of_id->compatible[0];
> + of_id++) {
> + const char *of_name;
> +
> + /* remove vendor prefix */
> + of_name = strnchr(of_id->compatible,
> + sizeof(of_id->compatible), ',');
> + if (of_name)
> + of_name++;
> + else
> + of_name = of_id->compatible;
> +
> + if (wdrv->driver.name) {
> + if (strcmp(wdrv->driver.name, of_name) == 0)
> + continue;
> + }
> +
> + pr_warn("Wiegand driver %s has no device_id for %s\n",
> + wdrv->driver.name, of_id->compatible);
> + }
> + }
This looks like very much of a repetition of the existing code somewhere.
...
> +/**
> + * struct wiegand_device - Wiegand listener device
> + * @dev - drivers structure of the device
> + * @id - unique device id
> + * @controller - Wiegand controller associated with the device
> + * @modalias - Name of the driver to use with this device, or its alias.
> + */
> +struct wiegand_device {
> + struct device dev;
> + u8 id;
> + struct wiegand_controller *controller;
> + char modalias[WIEGAND_NAME_SIZE];
> +};
Wondering if this can be made an opaque pointer instead.
...
> +/**
> + * struct wiegand_controller - Wiegand master or slave interface
> + * @dev - Device interface of the controller
> + * @list - Link with the global wiegand_controller list
> + * @bus_num - Board-specific identifier for Wiegand controller
> + * @pulse_len: length of the low pulse in usec; defaults to 50us
> + * @interval_len: length of a whole bit (both the pulse and the high phase) in usec;
> + * defaults to 2000us
> + * @frame_gap: length of the last bit of a frame (both the pulse and the high phase) in usec;
> + * defaults to interval_len
> + * device_count - Counter of devices connected to the same Wiegand bus(controller).
> + * devm_allocated - Whether the allocation of this struct is devres-managed
> + * slave - Whether the controller is a slave(receives data).
> + * transfer_message - Send a message on the bus.
> + * setup - Setup a device.
> + * cleanup - Cleanup after a device.
At some point you lost the grip on @ key button.
> + */
...
> +struct wiegand_driver {
> + const struct wiegand_device_id *id_table;
> + int (*probe)(struct wiegand_device *wiegand);
> + void (*remove)(struct wiegand_device *wiegand);
> + struct device_driver driver;
Making it first may save a few assembly instructions in pointer arithmetics.
Check if I'm right with bloat-o-meter (you will need a user of this data type,
of course).
> +};
...
> + driver_unregister(&wdrv->driver);
Yep, here and...
> + return drv ? container_of(drv, struct wiegand_driver, driver) : NULL;
...here you will save code bytes.
On Wed, Mar 01, 2023 at 06:23:54PM +0200, Andy Shevchenko wrote:
> On Wed, Mar 01, 2023 at 03:28:33PM +0100, Martin Zaťovič wrote:
...
> > +#include <linux/of.h>
> > +#include <linux/of_device.h>
Forgot to add that these are probably optional. Or at least OF specific code
should leave in a separate file with a good explanation why we even have it
to begin with.
Hi Martin,
I love your patch! Yet something to improve:
[auto build test ERROR on robh/for-next]
[also build test ERROR on linus/master v6.2 next-20230301]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Martin-Za-ovi/dt-bindings-wiegand-add-Wiegand-controller-common-properties/20230301-223030
base: https://git.kernel.org/pub/scm/linux/kernel/git/robh/linux.git for-next
patch link: https://lore.kernel.org/r/20230301142835.19614-3-m.zatovic1%40gmail.com
patch subject: [PATCHv3 2/4] wiegand: add Wiegand bus driver
config: sh-allmodconfig (https://download.01.org/0day-ci/archive/20230302/202303020615.0F00suDa-lkp@intel.com/config)
compiler: sh4-linux-gcc (GCC) 12.1.0
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/intel-lab-lkp/linux/commit/c62b833f42989e355d82cd20b7803e0228e33792
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Martin-Za-ovi/dt-bindings-wiegand-add-Wiegand-controller-common-properties/20230301-223030
git checkout c62b833f42989e355d82cd20b7803e0228e33792
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=sh olddefconfig
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=sh SHELL=/bin/bash drivers/wiegand/
If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>
| Link: https://lore.kernel.org/oe-kbuild-all/202303020615.0F00suDa-lkp@intel.com/
All errors (new ones prefixed by >>):
>> drivers/wiegand/wiegand.c:441:27: error: initialization of 'void (*)(struct device *)' from incompatible pointer type 'int (*)(struct device *)' [-Werror=incompatible-pointer-types]
441 | .remove = wiegand_remove,
| ^~~~~~~~~~~~~~
drivers/wiegand/wiegand.c:441:27: note: (near initialization for 'wiegand_bus_type.remove')
cc1: some warnings being treated as errors
vim +441 drivers/wiegand/wiegand.c
436
437 static struct bus_type wiegand_bus_type = {
438 .name = "wiegand",
439 .match = wiegand_match_device,
440 .probe = wiegand_probe,
> 441 .remove = wiegand_remove,
442 };
443
On Tue, Mar 14, 2023 at 01:34:40PM +0100, Martin Zaťovič wrote:
> Thank you for the code review Andy!
I'm not sure why you mentioned this in the reply to kernel build bot
message.
> Regarding the OF only code - I have been told, that implementing my own ID
> table
> so that a device can be added from another driver is no longer the way to
> go.
> The only other option I can think of is ACPI device enumeration, which I
> did not
> implement as I really believe that Wiegand will only be used on embedded
> devices.
>
> Despite that I respect the message - the code should be agnostic and count
> with
> every option so I will add ACPI support. Is there any other way of
> instantiating
> devices I am not aware of?
This is also seems to me unrelated to this message. Can you reply to
the correct message with enough context, please?
> st 1. 3. 2023 o 23:53 kernel test robot <lkp@intel.com> napísal(a):
>
> > Hi Martin,
> >
> > I love your patch! Yet something to improve:
> >
> > [auto build test ERROR on robh/for-next]
> > [also build test ERROR on linus/master v6.2 next-20230301]
> > [If your patch is applied to the wrong git tree, kindly drop us a note.
> > And when submitting patch, we suggest to use '--base' as documented in
> > https://git-scm.com/docs/git-format-patch#_base_tree_information]
> >
> > url:
> > https://github.com/intel-lab-lkp/linux/commits/Martin-Za-ovi/dt-bindings-wiegand-add-Wiegand-controller-common-properties/20230301-223030
> > base: https://git.kernel.org/pub/scm/linux/kernel/git/robh/linux.git
> > for-next
> > patch link:
> > https://lore.kernel.org/r/20230301142835.19614-3-m.zatovic1%40gmail.com
> > patch subject: [PATCHv3 2/4] wiegand: add Wiegand bus driver
> > config: sh-allmodconfig (
> > https://download.01.org/0day-ci/archive/20230302/202303020615.0F00suDa-lkp@intel.com/config
> > )
> > compiler: sh4-linux-gcc (GCC) 12.1.0
> > reproduce (this is a W=1 build):
> > wget
> > https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross
> > -O ~/bin/make.cross
> > chmod +x ~/bin/make.cross
> > #
> > https://github.com/intel-lab-lkp/linux/commit/c62b833f42989e355d82cd20b7803e0228e33792
> > git remote add linux-review https://github.com/intel-lab-lkp/linux
> > git fetch --no-tags linux-review
> > Martin-Za-ovi/dt-bindings-wiegand-add-Wiegand-controller-common-properties/20230301-223030
> > git checkout c62b833f42989e355d82cd20b7803e0228e33792
> > # save the config file
> > mkdir build_dir && cp config build_dir/.config
> > COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross
> > W=1 O=build_dir ARCH=sh olddefconfig
> > COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross
> > W=1 O=build_dir ARCH=sh SHELL=/bin/bash drivers/wiegand/
> >
> > If you fix the issue, kindly add following tag where applicable
> > | Reported-by: kernel test robot <lkp@intel.com>
> > | Link:
> > https://lore.kernel.org/oe-kbuild-all/202303020615.0F00suDa-lkp@intel.com/
> >
> > All errors (new ones prefixed by >>):
> >
> > >> drivers/wiegand/wiegand.c:441:27: error: initialization of 'void
> > (*)(struct device *)' from incompatible pointer type 'int (*)(struct device
> > *)' [-Werror=incompatible-pointer-types]
> > 441 | .remove = wiegand_remove,
> > | ^~~~~~~~~~~~~~
> > drivers/wiegand/wiegand.c:441:27: note: (near initialization for
> > 'wiegand_bus_type.remove')
> > cc1: some warnings being treated as errors
> >
> >
> > vim +441 drivers/wiegand/wiegand.c
> >
> > 436
> > 437 static struct bus_type wiegand_bus_type = {
> > 438 .name = "wiegand",
> > 439 .match = wiegand_match_device,
> > 440 .probe = wiegand_probe,
> > > 441 .remove = wiegand_remove,
> > 442 };
> > 443
> >
> > --
> > 0-DAY CI Kernel Test Service
> > https://github.com/intel/lkp-tests
> >
On Wed, Mar 01, 2023 at 06:23:54PM +0200, Andy Shevchenko wrote:
> On Wed, Mar 01, 2023 at 03:28:33PM +0100, Martin Zaťovič wrote:
> > Add a bus driver for Wiegand protocol. The bus driver handles
> > Wiegand controller and Wiegand device managemement and driver
> > matching. The bus driver defines the structures for Wiegand
> > controllers and Wiegand devices.
> >
> > Wiegand controller structure represents a master and contains
> > attributes such as the payload_len for configuring the size
> > of a single Wiegand message in bits. It also stores the
> > controller attributes defined in the devicetree.
> >
> > Each Wiegand controller should be associated with one Wiegand
> > device, as Wiegand is typically a point-to-point bus.
>
> ...
>
> > +#include <linux/device.h>
> > +#include <linux/dmaengine.h>
> > +#include <linux/dma-mapping.h>
> > +#include <linux/module.h>
> > +#include <linux/of.h>
> > +#include <linux/of_device.h>
> > +#include <linux/property.h>
> > +#include <linux/slab.h>
> > +#include <linux/wiegand.h>
> > +
> > +static struct bus_type wiegand_bus_type;
>
> > +static DEFINE_IDR(wiegand_controller_idr);
>
> Why not IDA or even xarray?
>
> ...
>
> > +static DEFINE_MUTEX(board_lock);
>
> Or locks need a good description for what they are.
>
> ...
>
> > +static void devm_wiegand_release_controller(struct device *dev, void *ctlr)
> > +{
> > + wiegand_controller_put(*(struct wiegand_controller **)ctlr);
> > +}
>
> This is not used in the following function, so can be moved closer to its user.
>
> ...
>
> > +struct wiegand_controller *devm_wiegand_alloc_controller(struct device *dev, unsigned int size,
> > + bool slave)
> > +{
> > + struct wiegand_controller **ptr, *ctlr;
> > +
> > + ptr = devres_alloc(devm_wiegand_release_controller, sizeof(*ptr), GFP_KERNEL);
> > + if (!ptr)
> > + return NULL;
> > +
> > + ctlr = wiegand_alloc_controller(dev, size, slave);
> > + if (ctlr) {
> > + ctlr->devm_allocated = true;
> > + *ptr = ctlr;
> > + devres_add(dev, ptr);
> > + } else {
> > + devres_free(ptr);
> > + }
> > +
> > + return ctlr;
>
> Can this utilize devm_add_action_or_reset()?
>
> > +}
>
> ...
>
> > +/**
> > + * of_register_wiegand_device - allocates and registers a new Wiegand device based on devicetree
>
> NAK for OF only code. New, esp. bus, code must be agnostic. We have all means
> for that.
In one of the previous versions of this patch series, there was also the possibility to instantiate
the device from another driver. I have been told, that this is not the way to go anymore, unless
there is a very specific reason for that. I did not find such reason, so I have removed this suport.
The only other device instantiating method I could think of is ACPI, however I believe it would be
just dead code no one would use, as the Wiegand interface is not normally used on non-embedded
devices. This is the point Evgeny Boger argued for as well. Is there any other device instantiating
method I am not aware of, that would be suitable for this bus?
> register_wiegand_device() or similar name.
>
> > + * node
> > + * @ctlr: controller structure to attach device to
> > + * @nc: devicetree node for the device
> > + */
> > +static struct wiegand_device *of_register_wiegand_device(struct wiegand_controller *ctlr,
>
> Ditto.
>
> > + struct device_node *nc)
>
> struct fwnode_handle *fwnode
>
> > +{
> > + struct wiegand_device *wiegand;
> > + int rc;
> > +
> > + wiegand = wiegand_alloc_device(ctlr);
> > + if (!wiegand) {
> > + dev_err(&ctlr->dev, "wiegad_device alloc error for %pOF\n", nc);
> > + rc = -ENOMEM;
> > + goto err_out;
> > + }
>
> > + of_node_get(nc);
> > + wiegand->dev.of_node = nc;
> > + wiegand->dev.fwnode = of_fwnode_handle(nc);
>
> device_set_node(&wiegand->dev, fwnode_handle_get(fwnode));
>
> > + rc = wiegand_add_device(wiegand);
> > + if (rc) {
> > + dev_err(&ctlr->dev, "wiegand_device register error %pOF\n", nc);
> > + goto err_of_node_put;
> > + }
> > +
> > + /* check if more devices are connected to the bus */
> > + if (ctlr->device_count > 1)
> > + dev_warn(&ctlr->dev, "Wiegand is a point-to-point bus, it is advised to only connect one device per Wiegand bus. The devices may not communicate using the same pulse length, format or else.\n");
> > +
> > + return wiegand;
> > +
> > +err_of_node_put:
> > + of_node_put(nc);
> > +err_out:
> > + wiegand_dev_put(wiegand);
> > + return ERR_PTR(rc);
> > +}
> > +
> > +/**
> > + * of_register_wiegand_devices - creates a wiegand device for all children of a controller
> > + * devicetree node
> > + * @ctlr: controller structure to check
> > + */
> > +static void of_register_wiegand_devices(struct wiegand_controller *ctlr)
> > +{
> > + struct wiegand_device *wiegand;
> > + struct device_node *nc;
> > +
> > + if (!ctlr->dev.of_node)
> > + return;
> > +
> > + for_each_available_child_of_node(ctlr->dev.of_node, nc) {
> > + if (of_node_test_and_set_flag(nc, OF_POPULATED))
> > + continue;
> > + wiegand = of_register_wiegand_device(ctlr, nc);
> > + if (IS_ERR(wiegand)) {
> > + dev_warn(&ctlr->dev, "Failed to create wiegand device for %pOF\n", nc);
> > + of_node_clear_flag(nc, OF_POPULATED);
> > + }
> > + }
>
> No way. Use agnostic approach. See above for some suggestions.
>
> > +}
>
> ...
>
> > + if (!dev)
> > + return -ENODEV;
>
> When is it true and why is it a problem?
>
> > + if (ctlr->dev.of_node) {
> > + id = of_alias_get_id(ctlr->dev.of_node, "wiegand");
>
> Why? What does this bring to us and why it's so important?
>
> > + if (id > 0) {
> > + ctlr->bus_num = id;
> > + mutex_lock(&board_lock);
> > + id = idr_alloc(&wiegand_controller_idr, ctlr, ctlr->bus_num,
> > + ctlr->bus_num + 1, GFP_KERNEL);
> > + mutex_unlock(&board_lock);
> > + if (WARN(id < 0, "couldn't get idr"))
> > + return id == -ENOSPC ? -EBUSY : id;
>
> Why rewriting error code?
>
> > + }
> > + device_property_read_u32(&ctlr->dev, "pulse-len-us", &ctlr->pulse_len);
> > + device_property_read_u32(&ctlr->dev, "interval-len-us", &ctlr->interval_len);
> > + device_property_read_u32(&ctlr->dev, "frame-gap-us", &ctlr->frame_gap);
> > + }
> > + if (ctlr->bus_num < 0) {
> > + first_dynamic = of_alias_get_highest_id("wiegand");
> > + if (first_dynamic < 0)
> > + first_dynamic = 0;
> > + else
> > + first_dynamic++;
> > +
> > + mutex_lock(&board_lock);
> > + id = idr_alloc(&wiegand_controller_idr, ctlr, first_dynamic,
> > + 0, GFP_KERNEL);
> > + mutex_unlock(&board_lock);
> > + if (WARN(id < 0, "couldn't get idr\n"))
> > + return id;
> > + ctlr->bus_num = id;
> > + }
> > +
> > + if (ctlr->pulse_len == 0) {
> > + dev_warn(&ctlr->dev, "pulse_len is not initialized, setting the default value 50us\n");
> > + ctlr->pulse_len = 50;
> > + }
> > + if (ctlr->interval_len == 0) {
> > + dev_warn(&ctlr->dev, "interval_len is not initialized, setting the default value 2000us\n");
> > + ctlr->interval_len = 2000;
> > + }
> > + if (ctlr->frame_gap == 0) {
> > + dev_warn(&ctlr->dev, "frame_gap is not initialized, setting the default value 2000us\n");
> > + ctlr->frame_gap = 2000;
> > + }
>
> Why warnings? Can't it survive without them? (See, for example, how I²C
> controllers get timings).
>
> > + dev_set_name(&ctlr->dev, "wiegand%u", ctlr->bus_num);
> > + ctlr->device_count = 0;
> > +
> > + status = device_add(&ctlr->dev);
> > + if (status < 0)
> > + goto free_bus_id;
> > +
> > + of_register_wiegand_devices(ctlr);
> > +
> > + return status;
> > +
> > +free_bus_id:
> > + mutex_lock(&board_lock);
> > + idr_remove(&wiegand_controller_idr, ctlr->bus_num);
> > + mutex_unlock(&board_lock);
> > + return status;
> > +}
>
> ...
>
> > +int devm_wiegand_register_controller(struct device *dev, struct wiegand_controller *ctlr)
> > +{
> > + struct wiegand_controller **ptr;
> > + int ret;
> > +
> > + ptr = devres_alloc(devm_wiegand_unregister, sizeof(*ptr), GFP_KERNEL);
> > + if (!ptr)
> > + return -ENOMEM;
> > +
> > + ret = wiegand_register_controller(ctlr);
> > + if (!ret) {
> > + *ptr = ctlr;
> > + devres_add(dev, ptr);
> > + } else {
> > + devres_free(ptr);
> > + }
>
> devm_add_action_or_reset() ?
>
> > + return ret;
> > +}
>
> ...
>
> > +struct wiegand_device *wiegand_alloc_device(struct wiegand_controller *ctlr)
> > +{
> > + struct wiegand_device *wiegand;
> > +
> > + if (!wiegand_controller_get(ctlr))
> > + return NULL;
>
> Is it important to be called before pure memory allocation? The reference
> counting on the existing resource is less failure prone, right?
>
> > + wiegand = kzalloc(sizeof(*wiegand), GFP_KERNEL);
> > + if (!wiegand) {
> > + wiegand_controller_put(ctlr);
> > + return NULL;
> > + }
> > +
> > + wiegand->controller = ctlr;
> > + wiegand->dev.parent = &ctlr->dev;
> > + wiegand->dev.bus = &wiegand_bus_type;
> > + wiegand->dev.release = wieganddev_release;
> > +
> > + device_initialize(&wiegand->dev);
> > + return wiegand;
> > +}
>
> ...
>
> > +static void wiegand_dev_set_name(struct wiegand_device *wiegand, u8 id)
> > +{
> > + dev_set_name(&wiegand->dev, "%s.%u", dev_name(&wiegand->controller->dev), id);
>
> Why error is ignored?
>
> > +}
>
> ...
>
> > + if (wiegand->dev.of_node) {
> > + of_node_clear_flag(wiegand->dev.of_node, OF_POPULATED);
> > + of_node_put(wiegand->dev.of_node);
> > + }
>
> fwnode APIs, please.
>
> ...
>
> > +static int wiegand_probe(struct device *dev)
> > +{
> > + struct wiegand_device *wiegand = to_wiegand_device(dev);
> > + const struct wiegand_driver *wdrv = to_wiegand_driver(dev->driver);
> > + int ret = 0;
> > +
> > + if (wdrv->probe)
> > + ret = wdrv->probe(wiegand);
> > +
> > + return ret;
>
> Hmm... this is just
>
> if (wdrv->probe)
> return wdrv->probe(wiegand);
>
> return 0;
>
> > +}
>
> ...
>
> > + if (wdrv->driver.of_match_table) {
> > + const struct of_device_id *of_id;
> > +
> > + for (of_id = wdrv->driver.of_match_table; of_id->compatible[0];
> > + of_id++) {
> > + const char *of_name;
> > +
> > + /* remove vendor prefix */
> > + of_name = strnchr(of_id->compatible,
> > + sizeof(of_id->compatible), ',');
> > + if (of_name)
> > + of_name++;
> > + else
> > + of_name = of_id->compatible;
> > +
> > + if (wdrv->driver.name) {
> > + if (strcmp(wdrv->driver.name, of_name) == 0)
> > + continue;
> > + }
> > +
> > + pr_warn("Wiegand driver %s has no device_id for %s\n",
> > + wdrv->driver.name, of_id->compatible);
> > + }
> > + }
>
> This looks like very much of a repetition of the existing code somewhere.
>
> ...
>
> > +/**
> > + * struct wiegand_device - Wiegand listener device
> > + * @dev - drivers structure of the device
> > + * @id - unique device id
> > + * @controller - Wiegand controller associated with the device
> > + * @modalias - Name of the driver to use with this device, or its alias.
> > + */
> > +struct wiegand_device {
> > + struct device dev;
> > + u8 id;
> > + struct wiegand_controller *controller;
> > + char modalias[WIEGAND_NAME_SIZE];
> > +};
>
> Wondering if this can be made an opaque pointer instead.
>
> ...
>
> > +/**
> > + * struct wiegand_controller - Wiegand master or slave interface
> > + * @dev - Device interface of the controller
> > + * @list - Link with the global wiegand_controller list
> > + * @bus_num - Board-specific identifier for Wiegand controller
> > + * @pulse_len: length of the low pulse in usec; defaults to 50us
> > + * @interval_len: length of a whole bit (both the pulse and the high phase) in usec;
> > + * defaults to 2000us
> > + * @frame_gap: length of the last bit of a frame (both the pulse and the high phase) in usec;
> > + * defaults to interval_len
> > + * device_count - Counter of devices connected to the same Wiegand bus(controller).
> > + * devm_allocated - Whether the allocation of this struct is devres-managed
> > + * slave - Whether the controller is a slave(receives data).
> > + * transfer_message - Send a message on the bus.
> > + * setup - Setup a device.
> > + * cleanup - Cleanup after a device.
>
> At some point you lost the grip on @ key button.
>
> > + */
>
> ...
>
> > +struct wiegand_driver {
> > + const struct wiegand_device_id *id_table;
> > + int (*probe)(struct wiegand_device *wiegand);
> > + void (*remove)(struct wiegand_device *wiegand);
>
> > + struct device_driver driver;
>
> Making it first may save a few assembly instructions in pointer arithmetics.
> Check if I'm right with bloat-o-meter (you will need a user of this data type,
> of course).
>
> > +};
>
> ...
>
> > + driver_unregister(&wdrv->driver);
>
> Yep, here and...
>
> > + return drv ? container_of(drv, struct wiegand_driver, driver) : NULL;
>
> ...here you will save code bytes.
>
> --
> With Best Regards,
> Andy Shevchenko
>
>
On Tue, Apr 4, 2023 at 3:13 PM Martin Zaťovič <m.zatovic1@gmail.com> wrote:
> On Wed, Mar 01, 2023 at 06:23:54PM +0200, Andy Shevchenko wrote:
> > > +/**
> > > + * of_register_wiegand_device - allocates and registers a new Wiegand device based on devicetree
> >
> > NAK for OF only code. New, esp. bus, code must be agnostic. We have all means
> > for that.
>
> In one of the previous versions of this patch series, there was also the possibility to instantiate
> the device from another driver. I have been told, that this is not the way to go anymore, unless
> there is a very specific reason for that. I did not find such reason, so I have removed this suport.
I don't know for sure but I think Andy simply means that you should take a look
in include/linux/property.h and replace every function named of_* with
the corresponding fwnode_* or device_* function from that file, and it
should all just magically work the same, but abstracted away from device
tree. It's not much more than a search/replace and rename operation
(unless there is a "hole" in the fwnode implementations... I hope not.)
In the end you can keep just <linux/property.h> and drop <linux/of.h>
and <linux/of_device.h> if this works.
Yours,
Linus Walleij
On Tue, Apr 04, 2023 at 10:30:59PM +0200, Linus Walleij wrote:
> On Tue, Apr 4, 2023 at 3:13 PM Martin Zaťovič <m.zatovic1@gmail.com> wrote:
> > On Wed, Mar 01, 2023 at 06:23:54PM +0200, Andy Shevchenko wrote:
...
> > > > +/**
> > > > + * of_register_wiegand_device - allocates and registers a new Wiegand device based on devicetree
> > >
> > > NAK for OF only code. New, esp. bus, code must be agnostic. We have all means
> > > for that.
> >
> > In one of the previous versions of this patch series, there was also the possibility to instantiate
> > the device from another driver. I have been told, that this is not the way to go anymore, unless
> > there is a very specific reason for that. I did not find such reason, so I have removed this suport.
>
> I don't know for sure but I think Andy simply means that you should take a look
> in include/linux/property.h and replace every function named of_* with
> the corresponding fwnode_* or device_* function from that file, and it
> should all just magically work the same, but abstracted away from device
> tree. It's not much more than a search/replace and rename operation
> (unless there is a "hole" in the fwnode implementations... I hope not.)
>
> In the end you can keep just <linux/property.h> and drop <linux/of.h>
> and <linux/of_device.h> if this works.
Yes. And the argument for embedded devices it's exactly why the non-OF
interface is needed as we want to have a possibility to connect devices on
ACPI (or another, if any) based platform without changing the code.
@@ -22516,6 +22516,8 @@ WIEGAND BUS DRIVER
M: Martin Zaťovič <m.zatovic1@gmail.com>
S: Maintained
F: Documentation/devicetree/bindings/wiegand/wiegand-controller.yaml
+F: drivers/wiegand/wiegand.c
+F: include/linux/wiegand.h
WIIMOTE HID DRIVER
M: David Rheinsberg <david.rheinsberg@gmail.com>
@@ -67,6 +67,8 @@ source "drivers/spi/Kconfig"
source "drivers/spmi/Kconfig"
+source "drivers/wiegand/Kconfig"
+
source "drivers/hsi/Kconfig"
source "drivers/pps/Kconfig"
@@ -150,6 +150,7 @@ obj-$(CONFIG_VHOST_RING) += vhost/
obj-$(CONFIG_VHOST_IOTLB) += vhost/
obj-$(CONFIG_VHOST) += vhost/
obj-$(CONFIG_VLYNQ) += vlynq/
+obj-$(CONFIG_WIEGAND) += wiegand/
obj-$(CONFIG_GREYBUS) += greybus/
obj-$(CONFIG_COMEDI) += comedi/
obj-$(CONFIG_STAGING) += staging/
new file mode 100644
@@ -0,0 +1,20 @@
+config WIEGAND
+ tristate "Wiegand Bus driver"
+ help
+ The "Wiegand Interface" is an asynchronous low-level protocol
+ or wiring standard. It is typically used for point-to-point
+ communication. The data length of Wiegand messages is not defined,
+ so the devices usually default to 26, 36 or 37 bits per message.
+ The throughput of Wiegand depends on the selected pulse length and
+ the intervals between pulses, in comparison to other busses it
+ is generally rather slow.
+
+ Despite its higher age, Wiegand remains widely used in access
+ control systems to connect a card swipe mechanism. Such mechanisms
+ utilize the Wiegand effect to transfer data from the card to
+ the reader.
+
+ Wiegand uses two wires to transmit the data D0 and D1. Both lines
+ are initially pulled up. When a bit of value 0 is being transmitted,
+ the D0 line is pulled down. Similarly, when a bit of value 1 is being
+ transmitted, the D1 line is pulled down.
new file mode 100644
@@ -0,0 +1 @@
+obj-$(CONFIG_WIEGAND) += wiegand.o
new file mode 100644
@@ -0,0 +1,500 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <linux/device.h>
+#include <linux/dmaengine.h>
+#include <linux/dma-mapping.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/property.h>
+#include <linux/slab.h>
+#include <linux/wiegand.h>
+
+static struct bus_type wiegand_bus_type;
+static DEFINE_IDR(wiegand_controller_idr);
+static DEFINE_MUTEX(board_lock);
+
+static void devm_wiegand_release_controller(struct device *dev, void *ctlr)
+{
+ wiegand_controller_put(*(struct wiegand_controller **)ctlr);
+}
+
+struct wiegand_controller *wiegand_alloc_controller(struct device *dev, unsigned int size,
+ bool slave)
+{
+ struct wiegand_controller *ctlr;
+ size_t ctlr_size = ALIGN(sizeof(*ctlr), dma_get_cache_alignment());
+
+ if (!dev)
+ return NULL;
+
+ ctlr = kzalloc(size + ctlr_size, GFP_KERNEL);
+ if (!ctlr)
+ return NULL;
+
+ device_initialize(&ctlr->dev);
+ ctlr->bus_num = -1;
+ ctlr->slave = slave;
+ ctlr->dev.parent = dev;
+ wiegand_controller_set_devdata(ctlr, (void *)ctlr + ctlr_size);
+
+ return ctlr;
+}
+EXPORT_SYMBOL_GPL(wiegand_alloc_controller);
+
+struct wiegand_controller *devm_wiegand_alloc_controller(struct device *dev, unsigned int size,
+ bool slave)
+{
+ struct wiegand_controller **ptr, *ctlr;
+
+ ptr = devres_alloc(devm_wiegand_release_controller, sizeof(*ptr), GFP_KERNEL);
+ if (!ptr)
+ return NULL;
+
+ ctlr = wiegand_alloc_controller(dev, size, slave);
+ if (ctlr) {
+ ctlr->devm_allocated = true;
+ *ptr = ctlr;
+ devres_add(dev, ptr);
+ } else {
+ devres_free(ptr);
+ }
+
+ return ctlr;
+}
+EXPORT_SYMBOL_GPL(devm_wiegand_alloc_controller);
+
+/**
+ * wiegand_controller_check_ops - checks whether message transfer function was defined for a
+ * controller
+ * @ctlr: controller structure to check
+ */
+static int wiegand_controller_check_ops(struct wiegand_controller *ctlr)
+{
+ if (!ctlr->transfer_message)
+ return -EINVAL;
+ return 0;
+}
+
+/**
+ * of_register_wiegand_device - allocates and registers a new Wiegand device based on devicetree
+ * node
+ * @ctlr: controller structure to attach device to
+ * @nc: devicetree node for the device
+ */
+static struct wiegand_device *of_register_wiegand_device(struct wiegand_controller *ctlr,
+ struct device_node *nc)
+{
+ struct wiegand_device *wiegand;
+ int rc;
+
+ wiegand = wiegand_alloc_device(ctlr);
+ if (!wiegand) {
+ dev_err(&ctlr->dev, "wiegad_device alloc error for %pOF\n", nc);
+ rc = -ENOMEM;
+ goto err_out;
+ }
+
+ of_node_get(nc);
+ wiegand->dev.of_node = nc;
+ wiegand->dev.fwnode = of_fwnode_handle(nc);
+
+ rc = wiegand_add_device(wiegand);
+ if (rc) {
+ dev_err(&ctlr->dev, "wiegand_device register error %pOF\n", nc);
+ goto err_of_node_put;
+ }
+
+ /* check if more devices are connected to the bus */
+ if (ctlr->device_count > 1)
+ dev_warn(&ctlr->dev, "Wiegand is a point-to-point bus, it is advised to only connect one device per Wiegand bus. The devices may not communicate using the same pulse length, format or else.\n");
+
+ return wiegand;
+
+err_of_node_put:
+ of_node_put(nc);
+err_out:
+ wiegand_dev_put(wiegand);
+ return ERR_PTR(rc);
+}
+
+/**
+ * of_register_wiegand_devices - creates a wiegand device for all children of a controller
+ * devicetree node
+ * @ctlr: controller structure to check
+ */
+static void of_register_wiegand_devices(struct wiegand_controller *ctlr)
+{
+ struct wiegand_device *wiegand;
+ struct device_node *nc;
+
+ if (!ctlr->dev.of_node)
+ return;
+
+ for_each_available_child_of_node(ctlr->dev.of_node, nc) {
+ if (of_node_test_and_set_flag(nc, OF_POPULATED))
+ continue;
+ wiegand = of_register_wiegand_device(ctlr, nc);
+ if (IS_ERR(wiegand)) {
+ dev_warn(&ctlr->dev, "Failed to create wiegand device for %pOF\n", nc);
+ of_node_clear_flag(nc, OF_POPULATED);
+ }
+ }
+}
+
+/**
+ * wiegand_register_controller - registers controller structure within bus
+ * @ctlr: controller structure to register
+ *
+ * Function checks that the message transfer functions is defined for passed controller structure,
+ * gets the devicetree defined attributes and checks whether they have all been initialized and
+ * finally adds the controller device and registers the controller on the bus.
+ */
+int wiegand_register_controller(struct wiegand_controller *ctlr)
+{
+ struct device *dev = ctlr->dev.parent;
+ int status, id, first_dynamic;
+
+ if (!dev)
+ return -ENODEV;
+
+ status = wiegand_controller_check_ops(ctlr);
+ if (status)
+ return status;
+
+ if (ctlr->dev.of_node) {
+ id = of_alias_get_id(ctlr->dev.of_node, "wiegand");
+ if (id > 0) {
+ ctlr->bus_num = id;
+ mutex_lock(&board_lock);
+ id = idr_alloc(&wiegand_controller_idr, ctlr, ctlr->bus_num,
+ ctlr->bus_num + 1, GFP_KERNEL);
+ mutex_unlock(&board_lock);
+ if (WARN(id < 0, "couldn't get idr"))
+ return id == -ENOSPC ? -EBUSY : id;
+ }
+ device_property_read_u32(&ctlr->dev, "pulse-len-us", &ctlr->pulse_len);
+ device_property_read_u32(&ctlr->dev, "interval-len-us", &ctlr->interval_len);
+ device_property_read_u32(&ctlr->dev, "frame-gap-us", &ctlr->frame_gap);
+ }
+ if (ctlr->bus_num < 0) {
+ first_dynamic = of_alias_get_highest_id("wiegand");
+ if (first_dynamic < 0)
+ first_dynamic = 0;
+ else
+ first_dynamic++;
+
+ mutex_lock(&board_lock);
+ id = idr_alloc(&wiegand_controller_idr, ctlr, first_dynamic,
+ 0, GFP_KERNEL);
+ mutex_unlock(&board_lock);
+ if (WARN(id < 0, "couldn't get idr\n"))
+ return id;
+ ctlr->bus_num = id;
+ }
+
+ if (ctlr->pulse_len == 0) {
+ dev_warn(&ctlr->dev, "pulse_len is not initialized, setting the default value 50us\n");
+ ctlr->pulse_len = 50;
+ }
+ if (ctlr->interval_len == 0) {
+ dev_warn(&ctlr->dev, "interval_len is not initialized, setting the default value 2000us\n");
+ ctlr->interval_len = 2000;
+ }
+ if (ctlr->frame_gap == 0) {
+ dev_warn(&ctlr->dev, "frame_gap is not initialized, setting the default value 2000us\n");
+ ctlr->frame_gap = 2000;
+ }
+
+ dev_set_name(&ctlr->dev, "wiegand%u", ctlr->bus_num);
+ ctlr->device_count = 0;
+
+ status = device_add(&ctlr->dev);
+ if (status < 0)
+ goto free_bus_id;
+
+ of_register_wiegand_devices(ctlr);
+
+ return status;
+
+free_bus_id:
+ mutex_lock(&board_lock);
+ idr_remove(&wiegand_controller_idr, ctlr->bus_num);
+ mutex_unlock(&board_lock);
+ return status;
+}
+
+static int __unregister(struct device *dev, void *null)
+{
+ wiegand_unregister_device(to_wiegand_device(dev));
+ return 0;
+}
+
+void wiegand_unregister_controller(struct wiegand_controller *ctlr)
+{
+ struct wiegand_controller *found;
+ int id = ctlr->bus_num;
+
+ device_for_each_child(&ctlr->dev, NULL, __unregister);
+ found = idr_find(&wiegand_controller_idr, id);
+ device_del(&ctlr->dev);
+
+ mutex_lock(&board_lock);
+ if (found == ctlr)
+ idr_remove(&wiegand_controller_idr, id);
+ mutex_unlock(&board_lock);
+
+ if (!ctlr->devm_allocated)
+ put_device(&ctlr->dev);
+}
+EXPORT_SYMBOL_GPL(wiegand_unregister_controller);
+
+static void devm_wiegand_unregister(struct device *dev, void *res)
+{
+ wiegand_unregister_controller(*(struct wiegand_controller **)res);
+}
+
+int devm_wiegand_register_controller(struct device *dev, struct wiegand_controller *ctlr)
+{
+ struct wiegand_controller **ptr;
+ int ret;
+
+ ptr = devres_alloc(devm_wiegand_unregister, sizeof(*ptr), GFP_KERNEL);
+ if (!ptr)
+ return -ENOMEM;
+
+ ret = wiegand_register_controller(ctlr);
+ if (!ret) {
+ *ptr = ctlr;
+ devres_add(dev, ptr);
+ } else {
+ devres_free(ptr);
+ }
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(devm_wiegand_register_controller);
+
+/* Device section */
+
+static void wieganddev_release(struct device *dev)
+{
+ struct wiegand_device *wiegand = to_wiegand_device(dev);
+
+ wiegand_controller_put(wiegand->controller);
+ kfree(wiegand);
+}
+
+struct wiegand_device *wiegand_alloc_device(struct wiegand_controller *ctlr)
+{
+ struct wiegand_device *wiegand;
+
+ if (!wiegand_controller_get(ctlr))
+ return NULL;
+
+ wiegand = kzalloc(sizeof(*wiegand), GFP_KERNEL);
+ if (!wiegand) {
+ wiegand_controller_put(ctlr);
+ return NULL;
+ }
+
+ wiegand->controller = ctlr;
+ wiegand->dev.parent = &ctlr->dev;
+ wiegand->dev.bus = &wiegand_bus_type;
+ wiegand->dev.release = wieganddev_release;
+
+ device_initialize(&wiegand->dev);
+ return wiegand;
+}
+EXPORT_SYMBOL_GPL(wiegand_alloc_device);
+
+static void wiegand_cleanup(struct wiegand_device *wiegand)
+{
+ if (wiegand->controller->cleanup)
+ wiegand->controller->cleanup(wiegand);
+}
+
+static int __wiegand_add_device(struct wiegand_device *wiegand)
+{
+ struct wiegand_controller *ctlr = wiegand->controller;
+ struct device *dev = ctlr->dev.parent;
+ int status;
+
+ status = wiegand_setup(wiegand);
+ if (status < 0) {
+ dev_err(dev, "can't setup %s, status %d\n",
+ dev_name(&wiegand->dev), status);
+ return status;
+ }
+
+ status = device_add(&wiegand->dev);
+ if (status < 0) {
+ dev_err(dev, "can't add %s, status %d\n", dev_name(&wiegand->dev), status);
+ wiegand_cleanup(wiegand);
+ } else {
+ dev_dbg(dev, "registered child %s\n", dev_name(&wiegand->dev));
+ }
+
+ return status;
+}
+
+static void wiegand_dev_set_name(struct wiegand_device *wiegand, u8 id)
+{
+ dev_set_name(&wiegand->dev, "%s.%u", dev_name(&wiegand->controller->dev), id);
+}
+
+int wiegand_add_device(struct wiegand_device *wiegand)
+{
+ struct wiegand_controller *ctlr = wiegand->controller;
+ int status;
+
+ wiegand_dev_set_name(wiegand, ctlr->device_count);
+
+ status = __wiegand_add_device(wiegand);
+ if (!status) {
+ ctlr->device_count++;
+ wiegand->id = wiegand->controller->device_count;
+ }
+
+ return status;
+}
+
+int wiegand_setup(struct wiegand_device *wiegand)
+{
+ int status = 0;
+
+ if (wiegand->controller->setup) {
+ status = wiegand->controller->setup(wiegand);
+ if (status) {
+ dev_err(&wiegand->controller->dev, "Failed to setup device: %d\n", status);
+ return status;
+ }
+ }
+
+ return status;
+}
+EXPORT_SYMBOL_GPL(wiegand_setup);
+
+void wiegand_unregister_device(struct wiegand_device *wiegand)
+{
+ if (!wiegand)
+ return;
+
+ if (wiegand->dev.of_node) {
+ of_node_clear_flag(wiegand->dev.of_node, OF_POPULATED);
+ of_node_put(wiegand->dev.of_node);
+ }
+ device_del(&wiegand->dev);
+ wiegand_cleanup(wiegand);
+ put_device(&wiegand->dev);
+}
+EXPORT_SYMBOL_GPL(wiegand_unregister_device);
+
+int wiegand_send_message(struct wiegand_device *wiegand, u8 *message, u8 bitlen)
+{
+ struct wiegand_master *master = wiegand->controller;
+
+ if (message == NULL || message == 0)
+ return -EINVAL;
+
+ if (master->transfer_message)
+ master->transfer_message(wiegand, message, bitlen);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(wiegand_send_message);
+
+static int wiegand_match_device(struct device *dev, struct device_driver *drv)
+{
+ if (of_driver_match_device(dev, drv))
+ return 1;
+
+ return 0;
+}
+
+static int wiegand_probe(struct device *dev)
+{
+ struct wiegand_device *wiegand = to_wiegand_device(dev);
+ const struct wiegand_driver *wdrv = to_wiegand_driver(dev->driver);
+ int ret = 0;
+
+ if (wdrv->probe)
+ ret = wdrv->probe(wiegand);
+
+ return ret;
+}
+
+static int wiegand_remove(struct device *dev)
+{
+ const struct wiegand_driver *wdrv = to_wiegand_driver(dev->driver);
+
+ if (wdrv->remove)
+ wdrv->remove(to_wiegand_device(dev));
+
+ return 0;
+}
+
+static struct bus_type wiegand_bus_type = {
+ .name = "wiegand",
+ .match = wiegand_match_device,
+ .probe = wiegand_probe,
+ .remove = wiegand_remove,
+};
+
+int __wiegand_register_driver(struct module *owner, struct wiegand_driver *wdrv)
+{
+ wdrv->driver.owner = owner;
+ wdrv->driver.bus = &wiegand_bus_type;
+
+ if (wdrv->driver.of_match_table) {
+ const struct of_device_id *of_id;
+
+ for (of_id = wdrv->driver.of_match_table; of_id->compatible[0];
+ of_id++) {
+ const char *of_name;
+
+ /* remove vendor prefix */
+ of_name = strnchr(of_id->compatible,
+ sizeof(of_id->compatible), ',');
+ if (of_name)
+ of_name++;
+ else
+ of_name = of_id->compatible;
+
+ if (wdrv->driver.name) {
+ if (strcmp(wdrv->driver.name, of_name) == 0)
+ continue;
+ }
+
+ pr_warn("Wiegand driver %s has no device_id for %s\n",
+ wdrv->driver.name, of_id->compatible);
+ }
+ }
+
+ return driver_register(&wdrv->driver);
+}
+EXPORT_SYMBOL_GPL(__wiegand_register_driver);
+
+static int __init wiegand_init(void)
+{
+ int ret;
+
+ ret = bus_register(&wiegand_bus_type);
+ if (ret < 0) {
+ pr_err("Wiegand bus registration failed: %d\n", ret);
+ return ret;
+ }
+
+ return 0;
+}
+
+static void __exit wiegand_exit(void)
+{
+ bus_unregister(&wiegand_bus_type);
+}
+postcore_initcall_sync(wiegand_init);
+module_exit(wiegand_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Wiegand bus driver");
+MODULE_AUTHOR("Martin Zaťovič <m.zatovic1@gmail.com>");
new file mode 100644
@@ -0,0 +1,155 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef H_LINUX_INCLUDE_LINUX_WIEGAND_H
+#define H_LINUX_INCLUDE_LINUX_WIEGAND_H
+
+#include <linux/device.h>
+#include <linux/mutex.h>
+#include <linux/mod_devicetable.h>
+
+#define WIEGAND_NAME_SIZE 32
+
+extern struct bus_type wiegand_type;
+
+/**
+ * struct wiegand_device - Wiegand listener device
+ * @dev - drivers structure of the device
+ * @id - unique device id
+ * @controller - Wiegand controller associated with the device
+ * @modalias - Name of the driver to use with this device, or its alias.
+ */
+struct wiegand_device {
+ struct device dev;
+ u8 id;
+ struct wiegand_controller *controller;
+ char modalias[WIEGAND_NAME_SIZE];
+};
+
+/**
+ * struct wiegand_controller - Wiegand master or slave interface
+ * @dev - Device interface of the controller
+ * @list - Link with the global wiegand_controller list
+ * @bus_num - Board-specific identifier for Wiegand controller
+ * @pulse_len: length of the low pulse in usec; defaults to 50us
+ * @interval_len: length of a whole bit (both the pulse and the high phase) in usec;
+ * defaults to 2000us
+ * @frame_gap: length of the last bit of a frame (both the pulse and the high phase) in usec;
+ * defaults to interval_len
+ * device_count - Counter of devices connected to the same Wiegand bus(controller).
+ * devm_allocated - Whether the allocation of this struct is devres-managed
+ * slave - Whether the controller is a slave(receives data).
+ * transfer_message - Send a message on the bus.
+ * setup - Setup a device.
+ * cleanup - Cleanup after a device.
+ */
+struct wiegand_controller {
+ struct device dev;
+
+ s16 bus_num;
+
+ bool slave;
+ bool devm_allocated;
+
+ u32 pulse_len;
+ u32 interval_len;
+ u32 frame_gap;
+ u32 payload_len;
+ u8 device_count;
+
+ int (*transfer_message)(struct wiegand_device *dev, u8 *message, u8 bitlen);
+ int (*setup)(struct wiegand_device *wiegand);
+ void (*cleanup)(struct wiegand_device *wiegand);
+};
+
+struct wiegand_driver {
+ const struct wiegand_device_id *id_table;
+ int (*probe)(struct wiegand_device *wiegand);
+ void (*remove)(struct wiegand_device *wiegand);
+ struct device_driver driver;
+};
+
+/* Wiegand controller section */
+
+#define wiegand_master wiegand_controller
+struct wiegand_controller *wiegand_alloc_controller(struct device *host, unsigned int size,
+ bool slave);
+
+struct wiegand_controller *devm_wiegand_alloc_controller(struct device *dev, unsigned int size,
+ bool slave);
+static inline struct wiegand_controller *devm_wiegand_alloc_master(struct device *dev,
+ unsigned int size)
+{
+ return devm_wiegand_alloc_controller(dev, size, false);
+}
+
+extern int wiegand_register_controller(struct wiegand_controller *ctlr);
+extern int devm_wiegand_register_controller(struct device *dev, struct wiegand_controller *ctlr);
+#define wiegand_register_master(_ctlr) wiegand_register_controller(_ctlr)
+#define devm_wiegand_register_master(_dev, _ctlr)devm_wiegand_register_controller(_dev, _ctlr)
+extern void wiegand_unregister_controller(struct wiegand_controller *ctlr);
+#define wiegand_unregister_master(_ctlr) wiegand_unregister_controller(_ctlr)
+extern struct wiegand_master *wiegand_busnum_to_master(u16 bus_num);
+
+static inline void *wiegand_controller_get_devdata(struct wiegand_controller *ctlr)
+{
+ return dev_get_drvdata(&ctlr->dev);
+}
+
+static inline void wiegand_controller_set_devdata(struct wiegand_controller *ctlr, void *data)
+{
+ dev_set_drvdata(&ctlr->dev, data);
+}
+
+#define wiegand_master_get_devdata(_ctlr) wiegand_controller_get_devdata(_ctlr)
+#define wiegand_master_set_devdata(_ctlr, _data) wiegand_controller_set_devdata(_ctlr, _data)
+
+static inline struct wiegand_controller *wiegand_controller_get(struct wiegand_controller *ctlr)
+{
+ if (!ctlr || !get_device(&ctlr->dev))
+ return NULL;
+ return ctlr;
+}
+
+static inline void wiegand_controller_put(struct wiegand_controller *ctlr)
+{
+ if (ctlr)
+ put_device(&ctlr->dev);
+}
+
+/* Wiegand device section */
+
+extern struct wiegand_device *wiegand_alloc_device(struct wiegand_controller *ctlr);
+extern int wiegand_add_device(struct wiegand_device *wiegand);
+extern int wiegand_setup(struct wiegand_device *wiegand);
+extern void wiegand_unregister_device(struct wiegand_device *wiegand);
+
+extern int wiegand_send_message(struct wiegand_device *wiegand, u8 *message, u8 bitlen);
+
+static inline struct wiegand_device *to_wiegand_device(struct device *dev)
+{
+ return dev ? container_of(dev, struct wiegand_device, dev) : NULL;
+}
+
+static inline void wiegand_dev_put(struct wiegand_device *wiegand)
+{
+ if (wiegand)
+ put_device(&wiegand->dev);
+}
+
+/* Wiegand driver section */
+
+extern int __wiegand_register_driver(struct module *owner, struct wiegand_driver *wdrv);
+#define wiegand_register_driver(driver) __wiegand_register_driver(THIS_MODULE, driver)
+
+static inline void wiegand_unregister_driver(struct wiegand_driver *wdrv)
+{
+ if (wdrv)
+ driver_unregister(&wdrv->driver);
+}
+
+static inline struct wiegand_driver *to_wiegand_driver(struct device_driver *drv)
+{
+ return drv ? container_of(drv, struct wiegand_driver, driver) : NULL;
+}
+
+#endif /* H_LINUX_INCLUDE_LINUX_WIEGAND_H */