* [RFCv2 PATCH 2/4] bus: add Wiegand bus driver
2022-10-05 14:57 [RFCv2 PATCH 1/4] dt-bindings: bus: add Wiegand bus dt documentation Martin Zaťovič
@ 2022-10-05 14:57 ` Martin Zaťovič
2022-10-06 8:29 ` Krzysztof Kozlowski
2022-10-17 8:49 ` Linus Walleij
2022-10-05 14:57 ` [RFCv2 PATCH 3/4] dt-bindings: gpio: add Wiegand GPIO driver dt documentation Martin Zaťovič
` (4 subsequent siblings)
5 siblings, 2 replies; 13+ messages in thread
From: Martin Zaťovič @ 2022-10-05 14:57 UTC (permalink / raw)
To: robh+dt, krzysztof.kozlowski+dt, linus.walleij, brgl, gregkh,
jeffrey.l.hugo, andersson, Michael.Srba, saravanak, mani,
hemantk, linux-kernel, devicetree, linux-gpio
Cc: Martin Zaťovič
The Wiegand bus driver spawns devices and matches them with
drivers.
Signed-off-by: Martin Zaťovič <m.zatovic1@gmail.com>
---
The bus driver currently assumes that any new Wiegand driver will
have a matching entry in the devicetree. It is currently sufficient
as I will only be implementing the GPIO driver. If someone
implements a Wiegand driver that will not use devicetree, he will
also have to edit this bus driver, in order to match properly. Is
that a correct approach?
---
drivers/bus/Kconfig | 6 +
drivers/bus/Makefile | 2 +
drivers/bus/wiegand.c | 339 ++++++++++++++++++++++++++++++++++++++++
include/linux/wiegand.h | 110 +++++++++++++
4 files changed, 457 insertions(+)
create mode 100644 drivers/bus/wiegand.c
create mode 100644 include/linux/wiegand.h
diff --git a/drivers/bus/Kconfig b/drivers/bus/Kconfig
index 7bfe998f3514..9675f5a13ffb 100644
--- a/drivers/bus/Kconfig
+++ b/drivers/bus/Kconfig
@@ -241,6 +241,12 @@ config VEXPRESS_CONFIG
Platform configuration infrastructure for the ARM Ltd.
Versatile Express.
+config WIEGAND
+ tristate "Wiegand bus"
+ help
+ Wiegand Protocol is a low level 2-wire serial protocol. This
+ enables the support of the bus.
+
config DA8XX_MSTPRI
bool "TI da8xx master peripheral priority driver"
depends on ARCH_DAVINCI_DA8XX
diff --git a/drivers/bus/Makefile b/drivers/bus/Makefile
index d90eed189a65..4a9fa6314e54 100644
--- a/drivers/bus/Makefile
+++ b/drivers/bus/Makefile
@@ -36,6 +36,8 @@ obj-$(CONFIG_TI_SYSC) += ti-sysc.o
obj-$(CONFIG_TS_NBUS) += ts-nbus.o
obj-$(CONFIG_UNIPHIER_SYSTEM_BUS) += uniphier-system-bus.o
obj-$(CONFIG_VEXPRESS_CONFIG) += vexpress-config.o
+obj-$(CONFIG_WIEGAND) += wiegand.o
+
obj-$(CONFIG_DA8XX_MSTPRI) += da8xx-mstpri.o
diff --git a/drivers/bus/wiegand.c b/drivers/bus/wiegand.c
new file mode 100644
index 000000000000..c76026d0c3b1
--- /dev/null
+++ b/drivers/bus/wiegand.c
@@ -0,0 +1,339 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/slab.h>
+#include <linux/wiegand.h>
+
+static const struct {
+ const char *name;
+ const char *desc;
+} wiegand_module_table[] = {
+ { NULL, NULL },
+ { "wiegand-gpio", "Wiegand GPIO write-only master" },
+};
+
+int wiegand_gpio_calc_parity8(u8 v)
+{
+ v = (v >> 4) ^ (v & ((1 << 4)-1));
+ v = (v >> 2) ^ (v & ((1 << 2)-1));
+ v = (v >> 1) ^ (v & ((1 << 1)-1));
+ return v;
+}
+EXPORT_SYMBOL_GPL(wiegand_gpio_calc_parity8);
+
+void wiegand_gpio_add_parity_to_data(unsigned char *tmp, u8 *data,
+ enum wiegand_format fmt)
+{
+ switch (fmt) {
+ case WIEGAND_V26:
+ data[0] = (tmp[0] >> 1) | (wiegand_gpio_calc_parity8(
+ tmp[0] ^ (tmp[1] & 0xf0)) << 7);
+ data[1] = (tmp[0] << 7) | (tmp[1] >> 1);
+ data[2] = (tmp[1] << 7) | (tmp[2] >> 1);
+ data[3] = (tmp[2] << 7) | (!wiegand_gpio_calc_parity8(
+ (tmp[1] & 0x0f) ^ tmp[2]) << 6);
+ break;
+ case WIEGAND_V36:
+ tmp[4] &= 0xc0;
+
+ data[0] = (tmp[0] >> 1) | (wiegand_gpio_calc_parity8(
+ tmp[0] ^ tmp[1] ^ (tmp[2] & 0x80)) << 7);
+ data[1] = (tmp[0] << 7) | (tmp[1] >> 1);
+ data[2] = (tmp[1] << 7) | (tmp[2] >> 1);
+ data[3] = (tmp[2] << 7) | (tmp[3] >> 1);
+ data[4] = (tmp[3] << 7) | (tmp[4] >> 1) |
+ (!wiegand_gpio_calc_parity8(
+ (tmp[2] & 0x7f) ^ tmp[3] ^ tmp[4]) << 4);
+ break;
+ case WIEGAND_V37:
+ tmp[4] &= 0xe0;
+
+ data[0] = (tmp[0] >> 1) | (wiegand_gpio_calc_parity8(
+ tmp[0] ^ tmp[1] ^ (tmp[2] & 0xc0)) << 7);
+ data[1] = (tmp[0] << 7) | (tmp[1] >> 1);
+ data[2] = (tmp[1] << 7) | (tmp[2] >> 1);
+ data[3] = (tmp[2] << 7) | (tmp[3] >> 1);
+ data[4] = (tmp[3] << 7) | (tmp[4] >> 1) |
+ (!wiegand_gpio_calc_parity8(
+ (tmp[2] & 0x7f) ^ tmp[3] ^ tmp[4]) << 3);
+ break;
+ default:
+ WARN_ON(fmt != WIEGAND_V37 &&
+ fmt != WIEGAND_V36 &&
+ fmt != WIEGAND_V26);
+ }
+}
+EXPORT_SYMBOL_GPL(wiegand_gpio_add_parity_to_data);
+
+static inline bool wiegand_module_known(unsigned int id)
+{
+ return id >= WIEGAND_MODULE_FIRST && id <= WIEGAND_MODULE_LAST;
+}
+
+static inline const char *wiegand_module_name(unsigned int id)
+{
+ if (wiegand_module_known(id))
+ return wiegand_module_table[id].name;
+ else
+ return "unknown";
+}
+
+static int wiegand_match(struct device *dev, struct device_driver *drv)
+{
+ struct wiegand_device *wdev = to_wiegand_device(dev);
+ struct wiegand_driver *wdrv = to_wiegand_driver(drv);
+ const enum wiegand_module_id *t;
+
+ if (of_driver_match_device(dev, drv))
+ return 1;
+
+ if (!wdrv->id_table)
+ return 0;
+
+ for (t = wdrv->id_table; *t; ++t)
+ if (*t == wdev->id)
+ return 1;
+
+ return 0;
+}
+
+static struct bus_type wiegand_bus_type = {
+ .name = "wiegand",
+ .match = wiegand_match,
+};
+
+int __wiegand_register_driver(struct module *owner,
+ struct wiegand_driver *wdrv)
+{
+ wdrv->driver.owner = owner;
+ wdrv->driver.bus = &wiegand_bus_type;
+ return driver_register(&wdrv->driver);
+}
+EXPORT_SYMBOL_GPL(__wiegand_register_driver);
+
+static int wiegand_dev_check(struct device *dev, void *data)
+{
+ struct wiegand_device *wdev = to_wiegand_device(dev);
+ struct wiegand_device *new_dev = data;
+
+ if (wdev->wiegand == new_dev->wiegand && wdev->id == new_dev->id &&
+ wdev->idx == new_dev->idx)
+ return -EBUSY;
+ return 0;
+}
+
+static void wiegand_dev_release(struct device *dev)
+{
+ struct wiegand_device *wdev = to_wiegand_device(dev);
+
+ put_device(wdev->wiegand->dev);
+ kfree(wdev);
+}
+
+static struct wiegand_device *
+wiegand_alloc_device(struct wiegand *wiegand)
+{
+ struct wiegand_device *dev;
+
+ if (!get_device(wiegand->dev))
+ return NULL;
+
+ dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+ if (!dev) {
+ put_device(wiegand->dev);
+ return NULL;
+ }
+
+ dev->wiegand = wiegand;
+ dev->dev.parent = wiegand->dev;
+ dev->dev.bus = &wiegand_bus_type;
+ dev->dev.release = wiegand_dev_release;
+
+ device_initialize(&dev->dev);
+
+ return dev;
+}
+
+static int wiegand_add_device(struct wiegand_device *dev)
+{
+ static DEFINE_MUTEX(add_mutex);
+ int ret;
+
+ if (dev->idx >= WIEGAND_MAX_MODULES)
+ return -EINVAL;
+
+ dev_set_name(&dev->dev, "wiegand-%s.%u", wiegand_module_name(dev->id),
+ dev->idx);
+
+ mutex_lock(&add_mutex);
+
+ ret = bus_for_each_dev(&wiegand_bus_type, NULL, dev,
+ wiegand_dev_check);
+ if (ret)
+ goto done;
+
+ ret = device_add(&dev->dev);
+ if (ret < 0)
+ dev_err(dev->wiegand->dev, "Can't add %s, status %d\n",
+ dev_name(dev->wiegand->dev), ret);
+
+done:
+ mutex_unlock(&add_mutex);
+ return ret;
+}
+
+static int __unregister(struct device *dev, void *null)
+{
+ if (dev->of_node)
+ of_node_put(dev->of_node);
+
+ device_unregister(dev);
+
+ return 0;
+}
+
+static struct wiegand_device *
+of_register_wiegand_device(struct wiegand *wiegand, struct device_node *nc)
+{
+ struct wiegand_device *dev;
+ const char *val;
+ int ret;
+
+ dev = wiegand_alloc_device(wiegand);
+ if (!dev) {
+ dev_err(wiegand->dev,
+ "Wiegand device alloc error for %pOF\n", nc);
+ return ERR_PTR(-ENOMEM);
+ }
+
+ ret = of_property_read_string(nc, "compatible", &val);
+ if (ret) {
+ dev_err(wiegand->dev, "%pOF has no valid 'compatible' property (%d)\n",
+ nc, ret);
+ goto err_put;
+ }
+
+ if (strcmp(val, "wiegand,wiegand-gpio") == 0) {
+ dev->idx = 0;
+ dev->id = WIEGAND_MODULE_GPIO;
+ wiegand->modules[0] = dev->id;
+ wiegand->count++;
+ }
+
+ of_node_get(nc);
+ dev->dev.of_node = nc;
+
+ ret = wiegand_add_device(dev);
+ if (ret) {
+ dev_err(wiegand->dev,
+ "Wiegand device register error for %pOF\n", nc);
+ of_node_put(nc);
+ goto err_put;
+ }
+
+ return dev;
+
+err_put:
+ put_device(&dev->dev);
+ return ERR_PTR(ret);
+}
+
+static void of_register_wiegand_devices(struct wiegand *wiegand)
+{
+ struct wiegand_device *dev;
+ struct device_node *nc;
+
+ if (!wiegand->dev->of_node)
+ return;
+
+ for_each_available_child_of_node(wiegand->dev->of_node, nc) {
+ dev = of_register_wiegand_device(wiegand, nc);
+ if (IS_ERR(dev)) {
+ dev_warn(wiegand->dev,
+ "Failed to create Wiegand device for %pOF\n",
+ nc);
+ }
+ }
+}
+
+static int wiegand_probe(struct platform_device *pdev)
+{
+ struct wiegand *wiegand;
+
+ wiegand = devm_kzalloc(&pdev->dev, sizeof(struct wiegand),
+ GFP_KERNEL);
+ if (!wiegand)
+ return -ENOMEM;
+
+ wiegand->dev = &pdev->dev;
+ dev_set_drvdata(&pdev->dev, wiegand);
+
+ mutex_init(&wiegand->lock);
+
+ of_register_wiegand_devices(wiegand);
+
+ return 0;
+}
+
+static int wiegand_remove(struct platform_device *pdev)
+{
+ struct wiegand *wiegand = dev_get_drvdata(&pdev->dev);
+
+ device_for_each_child(&pdev->dev, NULL, __unregister);
+
+ mutex_destroy(&wiegand->lock);
+
+ return 0;
+}
+
+static const struct of_device_id wiegand_dt_ids[] = {
+ { .compatible = "wiegand" },
+ {},
+};
+MODULE_DEVICE_TABLE(of, wiegand_dt_ids);
+
+static struct platform_driver wiegand_driver = {
+ .driver = {
+ .name = "wiegand",
+ .of_match_table = wiegand_dt_ids,
+ },
+ .probe = wiegand_probe,
+ .remove = wiegand_remove,
+};
+
+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);
+ goto error;
+ }
+
+ ret = platform_driver_register(&wiegand_driver);
+ if (ret < 0) {
+ pr_err("Wiegand driver registration failed: %d\n", ret);
+ goto error_bus;
+ }
+
+ return 0;
+
+error_bus:
+ bus_unregister(&wiegand_bus_type);
+error:
+ return ret;
+}
+postcore_initcall_sync(wiegand_init);
+
+static void __exit wiegand_exit(void)
+{
+ platform_driver_unregister(&wiegand_driver);
+ bus_unregister(&wiegand_bus_type);
+}
+module_exit(wiegand_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Wiegand bus driver");
+MODULE_AUTHOR("Martin Zaťovič <m.zatovic1@gmail.com>");
diff --git a/include/linux/wiegand.h b/include/linux/wiegand.h
new file mode 100644
index 000000000000..98d8671f042e
--- /dev/null
+++ b/include/linux/wiegand.h
@@ -0,0 +1,110 @@
+/* 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>
+
+#define WIEGAND_MAX_PAYLEN_BYTES 256
+#define WIEGAND_MAX_MODULES 1
+
+/* The used wiegand format; when data does not end at octet boundaries, the
+ * lower bits of the last octet will be ignored and only the upper ones will be
+ * used.
+ */
+enum wiegand_format {
+ WIEGAND_V26 = 26,
+ WIEGAND_V36 = 36,
+ WIEGAND_V37 = 37,
+ WIEGAND_CUSTOM = 0,
+};
+
+enum wiegand_module_id {
+ WIEGAND_MODULE_FIRST = 0x01,
+ WIEGAND_MODULE_GPIO = 0x01,
+ WIEGAND_MODULE_LAST = 0x01,
+};
+
+enum wiegand_paylen {
+ WIEGAND_V26_PAYLEN = 24,
+ WIEGAND_V36_PAYLEN = 34,
+ WIEGAND_V37_PAYLEN = 35,
+};
+
+extern struct bus_type wiegand_type;
+
+struct wiegand {
+ struct device *dev;
+ struct mutex lock;
+ int count;
+ u8 modules[WIEGAND_MAX_MODULES];
+};
+
+struct wiegand_driver {
+ const enum wiegand_module_id *id_table;
+ struct device_driver driver;
+};
+
+struct wiegand_device {
+ struct device dev;
+ struct wiegand *wiegand;
+ enum wiegand_module_id id;
+ unsigned int idx;
+};
+
+extern int __wiegand_register_driver(struct module *owner,
+ struct wiegand_driver *mdrv);
+
+static inline void wiegand_unregister_driver(struct wiegand_driver *mdrv)
+{
+ if (mdrv)
+ driver_unregister(&mdrv->driver);
+}
+
+#define wiegand_register_driver(driver) \
+ __wiegand_register_driver(THIS_MODULE, driver)
+
+#define module_wiegand_driver(__wiegand_driver) \
+ module_driver(__wiegand_driver, wiegand_register_driver, \
+ wiegand_unregister_driver)
+
+static inline struct wiegand_driver *
+to_wiegand_driver(struct device_driver *drv)
+{
+ if (!drv)
+ return NULL;
+ return container_of(drv, struct wiegand_driver, driver);
+}
+
+static inline struct wiegand_device *
+to_wiegand_device(struct device *dev)
+{
+ if (!dev)
+ return NULL;
+ return container_of(dev, struct wiegand_device, dev);
+}
+
+/**
+ * struct wiegand_setup - Wiegand communication attributes
+ * @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
+ * @format: the used wiegand format
+ * @payload_len: payload of wiegand message in bits
+ */
+struct wiegand_setup {
+ unsigned long pulse_len;
+ unsigned long interval_len;
+ unsigned long frame_gap;
+ enum wiegand_format format;
+ unsigned long payload_len;
+};
+
+extern int wiegand_gpio_calc_parity8(u8 v);
+extern void wiegand_gpio_add_parity_to_data(unsigned char *tmp, u8 *data,
+ enum wiegand_format fmt);
+
+#endif /* H_LINUX_INCLUDE_LINUX_WIEGAND_H */
--
2.37.3
^ permalink raw reply related [flat|nested] 13+ messages in thread* Re: [RFCv2 PATCH 2/4] bus: add Wiegand bus driver
2022-10-05 14:57 ` [RFCv2 PATCH 2/4] bus: add Wiegand bus driver Martin Zaťovič
@ 2022-10-06 8:29 ` Krzysztof Kozlowski
2022-10-17 8:49 ` Linus Walleij
1 sibling, 0 replies; 13+ messages in thread
From: Krzysztof Kozlowski @ 2022-10-06 8:29 UTC (permalink / raw)
To: Martin Zaťovič,
robh+dt, krzysztof.kozlowski+dt, linus.walleij, brgl, gregkh,
jeffrey.l.hugo, andersson, Michael.Srba, saravanak, mani,
hemantk, linux-kernel, devicetree, linux-gpio
On 05/10/2022 16:57, Martin Zaťovič wrote:
> The Wiegand bus driver spawns devices and matches them with
> drivers.
>
> Signed-off-by: Martin Zaťovič <m.zatovic1@gmail.com>
> ---
> The bus driver currently assumes that any new Wiegand driver will
> have a matching entry in the devicetree. It is currently sufficient
> as I will only be implementing the GPIO driver. If someone
> implements a Wiegand driver that will not use devicetree, he will
> also have to edit this bus driver, in order to match properly. Is
> that a correct approach?
(...)
> +static struct wiegand_device *
> +of_register_wiegand_device(struct wiegand *wiegand, struct device_node *nc)
> +{
> + struct wiegand_device *dev;
> + const char *val;
> + int ret;
> +
> + dev = wiegand_alloc_device(wiegand);
> + if (!dev) {
> + dev_err(wiegand->dev,
> + "Wiegand device alloc error for %pOF\n", nc);
> + return ERR_PTR(-ENOMEM);
> + }
> +
> + ret = of_property_read_string(nc, "compatible", &val);
> + if (ret) {
> + dev_err(wiegand->dev, "%pOF has no valid 'compatible' property (%d)\n",
> + nc, ret);
> + goto err_put;
> + }
> +
> + if (strcmp(val, "wiegand,wiegand-gpio") == 0) {
This does not look right. Bus can have any device attached, so limiting
some bus behavior to a specific device is not really scalable.
Anyway device and node matching should not be with strcmp but rather
of_*_match().
Best regards,
Krzysztof
^ permalink raw reply [flat|nested] 13+ messages in thread* Re: [RFCv2 PATCH 2/4] bus: add Wiegand bus driver
2022-10-05 14:57 ` [RFCv2 PATCH 2/4] bus: add Wiegand bus driver Martin Zaťovič
2022-10-06 8:29 ` Krzysztof Kozlowski
@ 2022-10-17 8:49 ` Linus Walleij
1 sibling, 0 replies; 13+ messages in thread
From: Linus Walleij @ 2022-10-17 8:49 UTC (permalink / raw)
To: Martin Zaťovič
Cc: robh+dt, krzysztof.kozlowski+dt, brgl, gregkh, jeffrey.l.hugo,
andersson, Michael.Srba, saravanak, mani, hemantk, linux-kernel,
devicetree, linux-gpio
On Wed, Oct 5, 2022 at 4:58 PM Martin Zaťovič <m.zatovic1@gmail.com> wrote:
> The Wiegand bus driver spawns devices and matches them with
> drivers.
>
> Signed-off-by: Martin Zaťovič <m.zatovic1@gmail.com>
Overall this is a vast improvement over the first patches!
I might not have time to look closer right now, but I see you got
a lot of comments from Krzysztof et al so you have some stuff to
work on.
Looking forward to the first non-RFC patch series!
Yours,
Linus Walleij
^ permalink raw reply [flat|nested] 13+ messages in thread
* [RFCv2 PATCH 3/4] dt-bindings: gpio: add Wiegand GPIO driver dt documentation
2022-10-05 14:57 [RFCv2 PATCH 1/4] dt-bindings: bus: add Wiegand bus dt documentation Martin Zaťovič
2022-10-05 14:57 ` [RFCv2 PATCH 2/4] bus: add Wiegand bus driver Martin Zaťovič
@ 2022-10-05 14:57 ` Martin Zaťovič
2022-10-06 2:18 ` Rob Herring
2022-10-06 8:23 ` Krzysztof Kozlowski
2022-10-05 14:57 ` [RFCv2 PATCH 4/4] gpio: add Wiegand GPIO driver Martin Zaťovič
` (3 subsequent siblings)
5 siblings, 2 replies; 13+ messages in thread
From: Martin Zaťovič @ 2022-10-05 14:57 UTC (permalink / raw)
To: robh+dt, krzysztof.kozlowski+dt, linus.walleij, brgl, gregkh,
jeffrey.l.hugo, andersson, Michael.Srba, saravanak, mani,
hemantk, linux-kernel, devicetree, linux-gpio
Cc: Martin Zaťovič
The Wiegand GPIO driver uses two GPIO lines to transmit data -
data-hi and data-lo. These lines need to be defined in the
devicetree, otherwise the driver will not probe successfully.
Signed-off-by: Martin Zaťovič <m.zatovic1@gmail.com>
---
.../bindings/gpio/gpio-wiegand.yaml | 53 +++++++++++++++++++
1 file changed, 53 insertions(+)
create mode 100644 Documentation/devicetree/bindings/gpio/gpio-wiegand.yaml
diff --git a/Documentation/devicetree/bindings/gpio/gpio-wiegand.yaml b/Documentation/devicetree/bindings/gpio/gpio-wiegand.yaml
new file mode 100644
index 000000000000..3b235667ae17
--- /dev/null
+++ b/Documentation/devicetree/bindings/gpio/gpio-wiegand.yaml
@@ -0,0 +1,53 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/gpio/gpio-wiegand.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Wiegand GPIO controller
+
+description: |
+ Wiegand GPIO controller running under Wiegand bus.
+
+maintainers:
+ - Martin Zaťovič <m.zatovic1@gmail.com>
+
+properties:
+ $nodename:
+ pattern: "^wiegand-gpio@[0-9a-f]+$"
+
+ compatible:
+ const: wiegand,wiegand-gpio
+
+ data-hi-gpios:
+ description: GPIO spec for data-hi line to use
+ maxItems: 1
+
+ data-lo-gpios:
+ description: GPIO spec for data-lo line to use
+ maxItems: 1
+
+required:
+ - compatible
+ - data-hi-gpios
+ - data-lo-gpios
+
+additionalProperties: false
+
+examples:
+ - |
+ #include <dt-bindings/gpio/gpio.h>
+
+ wiegand {
+ compatible = "wiegand";
+
+ wiegand-gpio {
+ compatible = "wiegand,wiegand-gpio";
+ pinctrl-names = "default";
+ pinctrl-0 = <&pinctrl_uart2_wiegand>;
+ data-hi-gpios = <&gpio2 7 (GPIO_ACTIVE_HIGH|GPIO_OPEN_DRAIN)>;
+ data-lo-gpios = <&gpio2 6 (GPIO_ACTIVE_HIGH|GPIO_OPEN_DRAIN)>;
+ };
+ };
+
+...
--
2.37.3
^ permalink raw reply related [flat|nested] 13+ messages in thread* Re: [RFCv2 PATCH 3/4] dt-bindings: gpio: add Wiegand GPIO driver dt documentation
2022-10-05 14:57 ` [RFCv2 PATCH 3/4] dt-bindings: gpio: add Wiegand GPIO driver dt documentation Martin Zaťovič
@ 2022-10-06 2:18 ` Rob Herring
2022-10-06 8:23 ` Krzysztof Kozlowski
1 sibling, 0 replies; 13+ messages in thread
From: Rob Herring @ 2022-10-06 2:18 UTC (permalink / raw)
To: Martin Zaťovič
Cc: devicetree, brgl, hemantk, robh+dt, andersson, mani, saravanak,
jeffrey.l.hugo, Michael.Srba, linux-gpio, linux-kernel, gregkh,
linus.walleij, krzysztof.kozlowski+dt
[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain, Size: 1960 bytes --]
On Wed, 05 Oct 2022 16:57:45 +0200, Martin Zaťovič wrote:
> The Wiegand GPIO driver uses two GPIO lines to transmit data -
> data-hi and data-lo. These lines need to be defined in the
> devicetree, otherwise the driver will not probe successfully.
>
> Signed-off-by: Martin Zaťovič <m.zatovic1@gmail.com>
> ---
> .../bindings/gpio/gpio-wiegand.yaml | 53 +++++++++++++++++++
> 1 file changed, 53 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/gpio/gpio-wiegand.yaml
>
My bot found errors running 'make DT_CHECKER_FLAGS=-m dt_binding_check'
on your patch (DT_CHECKER_FLAGS is new in v5.13):
yamllint warnings/errors:
dtschema/dtc warnings/errors:
/builds/robherring/dt-review-ci/linux/Documentation/devicetree/bindings/gpio/gpio-wiegand.example.dtb: wiegand: wiegand-gpio: {'compatible': ['wiegand,wiegand-gpio'], 'pinctrl-names': ['default'], 'pinctrl-0': [[4294967295]], 'data-hi-gpios': [[4294967295, 7, 6]], 'data-lo-gpios': [[4294967295, 6, 6]]} is not of type 'array'
From schema: /usr/local/lib/python3.10/dist-packages/dtschema/schemas/gpio/gpio-consumer.yaml
Documentation/devicetree/bindings/gpio/gpio-wiegand.example.dtb:0:0: /example-0/wiegand: failed to match any schema with compatible: ['wiegand']
/builds/robherring/dt-review-ci/linux/Documentation/devicetree/bindings/gpio/gpio-wiegand.example.dtb: wiegand-gpio: $nodename:0: 'wiegand-gpio' does not match '^wiegand-gpio@[0-9a-f]+$'
From schema: /builds/robherring/dt-review-ci/linux/Documentation/devicetree/bindings/gpio/gpio-wiegand.yaml
doc reference errors (make refcheckdocs):
See https://patchwork.ozlabs.org/patch/
This check can fail if there are any dependencies. The base for a patch
series is generally the most recent rc1.
If you already ran 'make dt_binding_check' and didn't see the above
error(s), then make sure 'yamllint' is installed and dt-schema is up to
date:
pip3 install dtschema --upgrade
Please check and re-submit.
^ permalink raw reply [flat|nested] 13+ messages in thread* Re: [RFCv2 PATCH 3/4] dt-bindings: gpio: add Wiegand GPIO driver dt documentation
2022-10-05 14:57 ` [RFCv2 PATCH 3/4] dt-bindings: gpio: add Wiegand GPIO driver dt documentation Martin Zaťovič
2022-10-06 2:18 ` Rob Herring
@ 2022-10-06 8:23 ` Krzysztof Kozlowski
2022-10-06 8:34 ` Krzysztof Kozlowski
1 sibling, 1 reply; 13+ messages in thread
From: Krzysztof Kozlowski @ 2022-10-06 8:23 UTC (permalink / raw)
To: Martin Zaťovič,
robh+dt, krzysztof.kozlowski+dt, linus.walleij, brgl, gregkh,
jeffrey.l.hugo, andersson, Michael.Srba, saravanak, mani,
hemantk, linux-kernel, devicetree, linux-gpio
On 05/10/2022 16:57, Martin Zaťovič wrote:
> The Wiegand GPIO driver uses two GPIO lines to transmit data -
> data-hi and data-lo. These lines need to be defined in the
> devicetree, otherwise the driver will not probe successfully.
>
> Signed-off-by: Martin Zaťovič <m.zatovic1@gmail.com>
> ---
> .../bindings/gpio/gpio-wiegand.yaml | 53 +++++++++++++++++++
> 1 file changed, 53 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/gpio/gpio-wiegand.yaml
>
> diff --git a/Documentation/devicetree/bindings/gpio/gpio-wiegand.yaml b/Documentation/devicetree/bindings/gpio/gpio-wiegand.yaml
> new file mode 100644
> index 000000000000..3b235667ae17
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/gpio/gpio-wiegand.yaml
> @@ -0,0 +1,53 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/gpio/gpio-wiegand.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Wiegand GPIO controller
> +
> +description: |
> + Wiegand GPIO controller running under Wiegand bus.
GPIO controllers need "gpio-controller" property, so this seems to be
something else.
> +
> +maintainers:
> + - Martin Zaťovič <m.zatovic1@gmail.com>
> +
> +properties:
> + $nodename:
> + pattern: "^wiegand-gpio@[0-9a-f]+$"
No need to enforce node name, unless this is for a class of devices. But
then why "gpio" not just "wiegand"?
> +
> + compatible:
> + const: wiegand,wiegand-gpio
> +
> + data-hi-gpios:
> + description: GPIO spec for data-hi line to use
> + maxItems: 1
> +
> + data-lo-gpios:
> + description: GPIO spec for data-lo line to use
> + maxItems: 1
> +
> +required:
> + - compatible
> + - data-hi-gpios
> + - data-lo-gpios
> +
> +additionalProperties: false
> +
> +examples:
> + - |
> + #include <dt-bindings/gpio/gpio.h>
> +
> + wiegand {
> + compatible = "wiegand";
> +
> + wiegand-gpio {
I have troubles understanding this. The "wiegand" node is the bus,
right? Then what is "wiegand-gpio"? GPIO controller? Then why it is not
marked as GPIO controller? What GPIOs does it control?
> + compatible = "wiegand,wiegand-gpio";
> + pinctrl-names = "default";
> + pinctrl-0 = <&pinctrl_uart2_wiegand>;
> + data-hi-gpios = <&gpio2 7 (GPIO_ACTIVE_HIGH|GPIO_OPEN_DRAIN)>;
> + data-lo-gpios = <&gpio2 6 (GPIO_ACTIVE_HIGH|GPIO_OPEN_DRAIN)>;
Aren't these properties of the bus, not the device?
> + };
> + };
> +
> +...
Best regards,
Krzysztof
^ permalink raw reply [flat|nested] 13+ messages in thread* Re: [RFCv2 PATCH 3/4] dt-bindings: gpio: add Wiegand GPIO driver dt documentation
2022-10-06 8:23 ` Krzysztof Kozlowski
@ 2022-10-06 8:34 ` Krzysztof Kozlowski
0 siblings, 0 replies; 13+ messages in thread
From: Krzysztof Kozlowski @ 2022-10-06 8:34 UTC (permalink / raw)
To: Martin Zaťovič,
robh+dt, krzysztof.kozlowski+dt, linus.walleij, brgl, gregkh,
jeffrey.l.hugo, andersson, Michael.Srba, saravanak, mani,
hemantk, linux-kernel, devicetree, linux-gpio
On 06/10/2022 10:23, Krzysztof Kozlowski wrote:
> On 05/10/2022 16:57, Martin Zaťovič wrote:
>> The Wiegand GPIO driver uses two GPIO lines to transmit data -
>> data-hi and data-lo. These lines need to be defined in the
>> devicetree, otherwise the driver will not probe successfully.
>>
>> Signed-off-by: Martin Zaťovič <m.zatovic1@gmail.com>
>> ---
>> .../bindings/gpio/gpio-wiegand.yaml | 53 +++++++++++++++++++
>> 1 file changed, 53 insertions(+)
>> create mode 100644 Documentation/devicetree/bindings/gpio/gpio-wiegand.yaml
>>
>> diff --git a/Documentation/devicetree/bindings/gpio/gpio-wiegand.yaml b/Documentation/devicetree/bindings/gpio/gpio-wiegand.yaml
>> new file mode 100644
>> index 000000000000..3b235667ae17
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/gpio/gpio-wiegand.yaml
>> @@ -0,0 +1,53 @@
>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>> +%YAML 1.2
>> +---
>> +$id: http://devicetree.org/schemas/gpio/gpio-wiegand.yaml#
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: Wiegand GPIO controller
>> +
>> +description: |
>> + Wiegand GPIO controller running under Wiegand bus.
>
> GPIO controllers need "gpio-controller" property, so this seems to be
> something else.
>
>> +
>> +maintainers:
>> + - Martin Zaťovič <m.zatovic1@gmail.com>
>> +
>> +properties:
>> + $nodename:
>> + pattern: "^wiegand-gpio@[0-9a-f]+$"
>
> No need to enforce node name, unless this is for a class of devices. But
> then why "gpio" not just "wiegand"?
>
>> +
>> + compatible:
>> + const: wiegand,wiegand-gpio
>> +
>> + data-hi-gpios:
>> + description: GPIO spec for data-hi line to use
>> + maxItems: 1
>> +
>> + data-lo-gpios:
>> + description: GPIO spec for data-lo line to use
>> + maxItems: 1
>> +
>> +required:
>> + - compatible
>> + - data-hi-gpios
>> + - data-lo-gpios
>> +
>> +additionalProperties: false
>> +
>> +examples:
>> + - |
>> + #include <dt-bindings/gpio/gpio.h>
>> +
>> + wiegand {
>> + compatible = "wiegand";
>> +
>> + wiegand-gpio {
>
> I have troubles understanding this. The "wiegand" node is the bus,
> right? Then what is "wiegand-gpio"? GPIO controller? Then why it is not
> marked as GPIO controller? What GPIOs does it control?
>
>> + compatible = "wiegand,wiegand-gpio";
>> + pinctrl-names = "default";
>> + pinctrl-0 = <&pinctrl_uart2_wiegand>;
>> + data-hi-gpios = <&gpio2 7 (GPIO_ACTIVE_HIGH|GPIO_OPEN_DRAIN)>;
>> + data-lo-gpios = <&gpio2 6 (GPIO_ACTIVE_HIGH|GPIO_OPEN_DRAIN)>;
>
> Aren't these properties of the bus, not the device?
So this looks like specific implementation of Wiegand bus - a Wiegand
bus controller. If it is correct, it should not be represented as child
of a bus... because this is a bus. IOW, just like SPI or I2C controllers
(why is this one different?), the bus is defined by SPI controller:
wiegand {
compatible = "wiegand,wiegand-gpio";
data-hi-gpios = <&gpio2 7 (GPIO_ACTIVE_HIGH|GPIO_OPEN_DRAIN)>;
data-lo-gpios = <&gpio2 6 (GPIO_ACTIVE_HIGH|GPIO_OPEN_DRAIN)>;
child-device, e.g. some-card {
compatible = "foo,bar";
// more properties of the device
};
};
Best regards,
Krzysztof
^ permalink raw reply [flat|nested] 13+ messages in thread
* [RFCv2 PATCH 4/4] gpio: add Wiegand GPIO driver
2022-10-05 14:57 [RFCv2 PATCH 1/4] dt-bindings: bus: add Wiegand bus dt documentation Martin Zaťovič
2022-10-05 14:57 ` [RFCv2 PATCH 2/4] bus: add Wiegand bus driver Martin Zaťovič
2022-10-05 14:57 ` [RFCv2 PATCH 3/4] dt-bindings: gpio: add Wiegand GPIO driver dt documentation Martin Zaťovič
@ 2022-10-05 14:57 ` Martin Zaťovič
2022-10-12 12:16 ` Bartosz Golaszewski
2022-10-06 2:18 ` [RFCv2 PATCH 1/4] dt-bindings: bus: add Wiegand bus dt documentation Rob Herring
` (2 subsequent siblings)
5 siblings, 1 reply; 13+ messages in thread
From: Martin Zaťovič @ 2022-10-05 14:57 UTC (permalink / raw)
To: robh+dt, krzysztof.kozlowski+dt, linus.walleij, brgl, gregkh,
jeffrey.l.hugo, andersson, Michael.Srba, saravanak, mani,
hemantk, linux-kernel, devicetree, linux-gpio
Cc: Martin Zaťovič
Wiegand GPIO driver uses GPIO lines defined in the devicetree to
transmit data following the Wiegand protocol.
Signed-off-by: Martin Zaťovič <m.zatovic1@gmail.com>
---
.../ABI/testing/sysfs-driver-gpio-wiegand | 40 ++
MAINTAINERS | 9 +
drivers/gpio/Kconfig | 7 +
drivers/gpio/Makefile | 1 +
drivers/gpio/gpio-wiegand.c | 492 ++++++++++++++++++
5 files changed, 549 insertions(+)
create mode 100644 Documentation/ABI/testing/sysfs-driver-gpio-wiegand
create mode 100644 drivers/gpio/gpio-wiegand.c
diff --git a/Documentation/ABI/testing/sysfs-driver-gpio-wiegand b/Documentation/ABI/testing/sysfs-driver-gpio-wiegand
new file mode 100644
index 000000000000..efcce06968ef
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-driver-gpio-wiegand
@@ -0,0 +1,40 @@
+What: /sys/devices/platform/.../wiegand-gpio-attributes/format
+Date: October 2022
+Contact: Martin Zaťovič <m.zatovic1@gmail.com>
+Description: Sets a format of Wiegand communication. Currently supported
+ formats are 26, 36 and 37 bits. These formats automatically add
+ checksums to the first and last bits of a message. To set a custom
+ format, 0 needs to be written here. Custom format writes an amount of
+ bits defined by payload_len(see below) and it does not add checksums so
+ the user is responsible for that.
+Users: any user space application which wants to communicate using Wiegand
+
+What: /sys/devices/platform/.../wiegand-gpio-attributes/payload_len
+Date: October 2022
+Contact: Martin Zaťovič <sampaio.ime@gmail.com>
+Description: Depends on format attribute - using one of the standard formats
+ the payload_len attribute file becomes read-only and it contains the
+ number of bits of a message without the checksum bits(e.g. 24 for
+ 26-bit format). Using a custom format makes this file writable for
+ configuring the Wiegand message length in bits.
+Users: any user space application which wants to communicate using Wiegand
+
+What: /sys/devices/platform/.../wiegand-gpio-attributes/pulse_len
+Date: October 2022
+Contact: Martin Zaťovič
+Description: Length of the low pulse in usecs; defaults to 50us.
+Users: any user space application which wants to communicate using Wiegand
+
+What: /sys/devices/platform/.../wiegand-gpio-attributes/interval_len
+Date: October 2022
+Contact: Martin Zaťovič
+Description: Length of the whole bit(both the pulse and the high phase) in
+ usecs; defaults to 2000us
+Users: any user space application which wants to communicate using Wiegand
+
+What: /sys/devices/platform/.../wiegand-gpio-attributes/frame_gap
+Date: October 2022
+Contact: Martin Zaťovič
+Description: Length of the last bit of a frame(both the pulse and the high
+ phase) in usecs; defaults to interval_len
+Users: any user space application which wants to communicate using Wiegand
diff --git a/MAINTAINERS b/MAINTAINERS
index 8656ab794786..43b21bd5333a 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -21960,6 +21960,15 @@ L: linux-input@vger.kernel.org
S: Maintained
F: drivers/hid/hid-wiimote*
+WIEGAND DRIVER
+M: Martin Zaťovič <m.zatovic1@gmail.com>
+S: Maintained
+F: Documentation/devicetree/bindings/bus/wiegand.yaml
+F: Documentation/devicetree/bindings/gpio/gpio-wiegand.yaml
+F: drivers/bus/wiegand.c
+F: drivers/gpio/gpio-wiegand.c
+F: include/linux/wiegand.h
+
WILOCITY WIL6210 WIRELESS DRIVER
L: linux-wireless@vger.kernel.org
S: Orphan
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 0642f579196f..3cd57e28df19 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -703,6 +703,13 @@ config GPIO_VX855
Additional drivers must be enabled in order to use the
functionality of the device.
+config GPIO_WIEGAND
+ tristate "Wiegand GPIO support"
+ depends on WIEGAND
+ help
+ This enables the GPIO module for Wiegand protocol communication.
+ The Wiegand bus driver has to be enabled first.
+
config GPIO_WCD934X
tristate "Qualcomm Technologies Inc WCD9340/WCD9341 GPIO controller driver"
depends on MFD_WCD934X && OF_GPIO
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index a0985d30f51b..09024e291cc4 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -173,6 +173,7 @@ obj-$(CONFIG_GPIO_VISCONTI) += gpio-visconti.o
obj-$(CONFIG_GPIO_VX855) += gpio-vx855.o
obj-$(CONFIG_GPIO_WCD934X) += gpio-wcd934x.o
obj-$(CONFIG_GPIO_WHISKEY_COVE) += gpio-wcove.o
+obj-$(CONFIG_GPIO_WIEGAND) += gpio-wiegand.o
obj-$(CONFIG_GPIO_WINBOND) += gpio-winbond.o
obj-$(CONFIG_GPIO_WM831X) += gpio-wm831x.o
obj-$(CONFIG_GPIO_WM8350) += gpio-wm8350.o
diff --git a/drivers/gpio/gpio-wiegand.c b/drivers/gpio/gpio-wiegand.c
new file mode 100644
index 000000000000..b45e39010fd6
--- /dev/null
+++ b/drivers/gpio/gpio-wiegand.c
@@ -0,0 +1,492 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <linux/delay.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/poll.h>
+#include <linux/miscdevice.h>
+#include <linux/of.h>
+#include <linux/gpio/consumer.h>
+#include <linux/wiegand.h>
+
+struct wiegand_gpio_device *wiegand_gpio_glob;
+
+struct wiegand_gpio_device {
+ struct device *dev;
+ struct miscdevice *misc_dev;
+ struct mutex mutex;
+ struct gpio_desc *gpio_data_hi;
+ struct gpio_desc *gpio_data_lo;
+ struct wiegand_setup setup;
+ u8 data[WIEGAND_MAX_PAYLEN_BYTES];
+};
+
+struct wiegand_gpio_instance {
+ struct wiegand_gpio_device *dev;
+ unsigned long flags;
+};
+
+static const struct wiegand_setup WIEGAND_SETUP = {
+ .pulse_len = 50,
+ .interval_len = 2000,
+ .frame_gap = 2000,
+ .format = WIEGAND_V26,
+ .payload_len = 24,
+};
+
+/*
+ * To send a bit of value 1 following the wiegand protocol, one must set
+ * the wiegand_data_hi to low for the duration of pulse. Similarly to send
+ * a bit of value 0, the wiegand_data_lo is set to low for pulse duration.
+ * This way the two lines are never low ar the same time.
+ */
+void wiegand_gpio_send_bit(struct wiegand_gpio_device *wiegand_gpio,
+ bool value, bool last)
+{
+ struct wiegand_setup *setup = &wiegand_gpio->setup;
+ struct gpio_desc *gpio = value ? wiegand_gpio->gpio_data_hi
+ : wiegand_gpio->gpio_data_lo;
+
+ gpiod_set_value_cansleep(gpio, 0);
+ udelay(setup->pulse_len);
+ gpiod_set_value_cansleep(gpio, 1);
+
+ if (last)
+ udelay(setup->frame_gap - setup->pulse_len);
+ else
+ udelay(setup->interval_len - setup->pulse_len);
+}
+
+/* This function is used for custom format */
+static int wiegand_gpio_write_by_bits(struct wiegand_gpio_device *wiegand_gpio,
+ size_t len)
+{
+ size_t i, bitlen;
+ bool bit_value, is_last_bit;
+ struct wiegand_setup *setup = &wiegand_gpio->setup;
+
+ bitlen = setup->format ? setup->payload_len + 2 : setup->payload_len;
+
+ for (i = 0; i < bitlen; i++) {
+ bit_value = ((wiegand_gpio->data[i / 8] >> (7 - (i % 8)))
+ & 0x01);
+ is_last_bit = (i + 1) == bitlen;
+
+ wiegand_gpio_send_bit(wiegand_gpio, (bool)bit_value,
+ is_last_bit);
+ }
+
+ return 0;
+}
+
+static unsigned int wiegand_gpio_calc_bytes(unsigned int bits)
+{
+ if (bits % 8 != 0)
+ return (bits / 8) + 1;
+ else
+ return bits / 8;
+}
+
+static unsigned int wiegand_gpio_get_payload_size(
+ unsigned long payload_len_bits,
+ enum wiegand_format fmt)
+{
+ unsigned int ret;
+
+ if (fmt == WIEGAND_CUSTOM)
+ ret = wiegand_gpio_calc_bytes(payload_len_bits);
+ else
+ /* add 2 for parity bits */
+ ret = wiegand_gpio_calc_bytes(payload_len_bits + 2);
+
+ return ret;
+}
+
+static ssize_t wiegand_gpio_get_user_data(
+ struct wiegand_gpio_device *wiegand_gpio,
+ char __user const *buf, size_t len)
+{
+ size_t rc;
+ size_t num_copy;
+ unsigned char tmp[WIEGAND_MAX_PAYLEN_BYTES];
+ struct wiegand_setup *setup = &wiegand_gpio->setup;
+
+ num_copy = wiegand_gpio_get_payload_size(setup->payload_len,
+ setup->format);
+
+ if (setup->format == WIEGAND_CUSTOM) {
+ rc = copy_from_user(&wiegand_gpio->data[0], buf, num_copy);
+ if (rc < 0)
+ return rc;
+ } else {
+ rc = copy_from_user(tmp, buf, num_copy);
+ if (rc < 0)
+ return rc;
+ wiegand_gpio_add_parity_to_data(tmp, wiegand_gpio->data,
+ setup->format);
+ }
+ return num_copy;
+}
+
+static int wiegand_gpio_release(struct inode *ino, struct file *filp)
+{
+ struct wiegand_gpio_instance *info = filp->private_data;
+ struct wiegand_gpio_device *wiegand_gpio = info->dev;
+
+ mutex_lock(&wiegand_gpio->mutex);
+ mutex_unlock(&wiegand_gpio->mutex);
+
+ kfree(info);
+
+ return 0;
+}
+
+static ssize_t wiegand_gpio_write(struct file *filp,
+ char __user const *buf, size_t len, loff_t *offset)
+{
+ struct wiegand_gpio_instance *info = filp->private_data;
+ struct wiegand_gpio_device *wiegand_gpio = info->dev;
+ int rc;
+
+ if (len * 8 < wiegand_gpio->setup.payload_len)
+ return -EBADMSG;
+ if (buf == NULL || len == 0)
+ return -EINVAL;
+
+ wiegand_gpio_get_user_data(wiegand_gpio, buf, len);
+ rc = wiegand_gpio_write_by_bits(wiegand_gpio, len);
+
+ return len;
+}
+
+static int wiegand_gpio_open(struct inode *ino, struct file *filp)
+{
+ struct wiegand_gpio_device *wiegand_gpio;
+ struct wiegand_gpio_instance *info;
+ int rc;
+
+ wiegand_gpio = wiegand_gpio_glob;
+
+ mutex_lock(&wiegand_gpio->mutex);
+
+ if ((filp->f_flags & O_ACCMODE) == O_RDONLY ||
+ (filp->f_flags & O_ACCMODE) == O_RDWR) {
+ dev_err(wiegand_gpio->dev, "Device is write only\n");
+ rc = -EIO;
+ goto err;
+ }
+
+ info = kzalloc(sizeof(*info), GFP_KERNEL);
+ if (!info) {
+ rc = -ENOMEM;
+ goto err;
+ }
+
+ gpiod_direction_output(wiegand_gpio->gpio_data_hi, 1);
+ gpiod_direction_output(wiegand_gpio->gpio_data_lo, 1);
+
+ info->dev = wiegand_gpio;
+ info->flags = filp->f_flags;
+
+ mutex_unlock(&wiegand_gpio->mutex);
+
+ filp->private_data = info;
+
+ return 0;
+err:
+ mutex_unlock(&wiegand_gpio->mutex);
+
+ return rc;
+}
+
+const struct file_operations wiegand_gpio_fops = {
+ .owner = THIS_MODULE,
+ .open = wiegand_gpio_open,
+ .release = wiegand_gpio_release,
+ .write = wiegand_gpio_write,
+};
+
+static struct miscdevice wiegand_misc_device = {
+ .minor = MISC_DYNAMIC_MINOR,
+ .name = "wiegand-gpio",
+ .fops = &wiegand_gpio_fops,
+};
+
+static ssize_t store_ulong(unsigned long *val, const char *buf,
+ size_t size, unsigned long max)
+{
+ int ret;
+ unsigned long new;
+
+ ret = kstrtoul(buf, 0, &new);
+ if (ret)
+ return ret;
+ if (max != 0 && new > max)
+ return -EINVAL;
+
+ *val = new;
+ return size;
+}
+
+ssize_t pulse_len_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ struct wiegand_gpio_device *device = dev_get_drvdata(dev);
+
+ if (!device)
+ return -ENODEV;
+
+ return sysfs_emit(buf, "%lu\n", device->setup.pulse_len);
+}
+
+ssize_t pulse_len_store(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct wiegand_gpio_device *device = dev_get_drvdata(dev);
+
+ if (!device)
+ return -ENODEV;
+
+ return store_ulong(&(device->setup.pulse_len), buf, count, 0);
+}
+
+ssize_t interval_len_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ struct wiegand_gpio_device *device = dev_get_drvdata(dev);
+
+ if (!device)
+ return -ENODEV;
+
+ return sysfs_emit(buf, "%lu\n", device->setup.pulse_len);
+}
+
+ssize_t interval_len_store(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct wiegand_gpio_device *device = dev_get_drvdata(dev);
+
+ if (!device)
+ return -ENODEV;
+
+ return store_ulong(&(device->setup.interval_len), buf, count, 0);
+}
+
+ssize_t frame_gap_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ struct wiegand_gpio_device *device = dev_get_drvdata(dev);
+
+ if (!device)
+ return -ENODEV;
+
+ return sysfs_emit(buf, "%lu\n", device->setup.frame_gap);
+}
+
+ssize_t frame_gap_store(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct wiegand_gpio_device *device = dev_get_drvdata(dev);
+
+ if (!device)
+ return -ENODEV;
+
+ return store_ulong(&(device->setup.frame_gap), buf, count, 0);
+}
+
+ssize_t format_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ struct wiegand_gpio_device *device = dev_get_drvdata(dev);
+
+ if (!device)
+ return -ENODEV;
+
+ return sysfs_emit(buf, "%u\n", device->setup.format);
+}
+
+/*
+ * To set a particular format, the number of bits the driver is supposed to
+ * transmit is written to the format sysfs file. For standard formats, the
+ * allowed inputs are 26, 36 and 37. To set a custom format, 0 is passed.
+ */
+ssize_t format_store(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ int ret;
+ unsigned long new;
+ enum wiegand_format *val;
+ struct wiegand_gpio_device *device = dev_get_drvdata(dev);
+
+ if (!device)
+ return -ENODEV;
+
+ val = &(device->setup.format);
+
+ ret = kstrtoul(buf, 0, &new);
+ if (ret)
+ return ret;
+
+ switch (new) {
+ case 0:
+ *val = WIEGAND_CUSTOM;
+ break;
+ case 26:
+ *val = WIEGAND_V26;
+ device->setup.payload_len = WIEGAND_V26_PAYLEN;
+ break;
+ case 36:
+ *val = WIEGAND_V36;
+ device->setup.payload_len = WIEGAND_V36_PAYLEN;
+ break;
+ case 37:
+ *val = WIEGAND_V37;
+ device->setup.payload_len = WIEGAND_V37_PAYLEN;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ return count;
+}
+
+/*
+ * Using a custom format, the payload_len sysfs file configures the size of
+ * messages payload in bits. When one of the standard formats is used, this
+ * file is read-only and contains the size of the message in bits without the
+ * parity bits.
+ */
+ssize_t payload_len_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct wiegand_gpio_device *device = dev_get_drvdata(dev);
+
+ if (!device)
+ return -ENODEV;
+
+ return sysfs_emit(buf, "%lu\n", device->setup.pulse_len);
+}
+
+ssize_t payload_len_store(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t count)
+{
+ struct wiegand_gpio_device *device = dev_get_drvdata(dev);
+
+ if (!device)
+ return -ENODEV;
+
+ /* standard formats use fixed payload size */
+ if (device->setup.format != WIEGAND_CUSTOM)
+ return -EPERM;
+
+ return store_ulong(&(device->setup.payload_len), buf, count,
+ WIEGAND_MAX_PAYLEN_BYTES * 8);
+}
+
+DEVICE_ATTR_RW(pulse_len);
+DEVICE_ATTR_RW(interval_len);
+DEVICE_ATTR_RW(frame_gap);
+DEVICE_ATTR_RW(format);
+DEVICE_ATTR_RW(payload_len);
+
+static struct attribute *wiegand_attrs[] = {
+ &dev_attr_pulse_len.attr,
+ &dev_attr_interval_len.attr,
+ &dev_attr_frame_gap.attr,
+ &dev_attr_format.attr,
+ &dev_attr_payload_len.attr,
+ NULL,
+};
+
+static struct attribute_group wiegand_group = {
+ .name = "wiegand-gpio-attributes",
+ .attrs = wiegand_attrs,
+};
+
+static int wiegand_gpio_dev_probe(struct device *device)
+{
+ int rc;
+ struct wiegand_gpio_device *wiegand_gpio;
+
+ wiegand_gpio = devm_kzalloc(device, sizeof(*wiegand_gpio), GFP_KERNEL);
+ if (!wiegand_gpio)
+ return -ENOMEM;
+
+ wiegand_gpio->dev = device;
+ wiegand_gpio->misc_dev = &wiegand_misc_device;
+
+ wiegand_gpio_glob = wiegand_gpio;
+
+ /* Get GPIO lines using device tree bindings. */
+ wiegand_gpio->gpio_data_lo = devm_gpiod_get(wiegand_gpio->dev,
+ "data-lo", GPIOD_OUT_HIGH);
+ if (IS_ERR(wiegand_gpio->gpio_data_lo)) {
+ return dev_err_probe(wiegand_gpio->dev,
+ PTR_ERR(wiegand_gpio->gpio_data_lo),
+ "Can't get data-lo line.");
+ }
+ wiegand_gpio->gpio_data_hi = devm_gpiod_get(wiegand_gpio->dev,
+ "data-hi", GPIOD_OUT_HIGH);
+ if (IS_ERR(wiegand_gpio->gpio_data_hi)) {
+ return dev_err_probe(wiegand_gpio->dev,
+ PTR_ERR(wiegand_gpio->gpio_data_hi),
+ "Can't get data-hi line.");
+ }
+
+ rc = sysfs_create_group(&wiegand_gpio->dev->kobj, &wiegand_group);
+ if (rc < 0) {
+ dev_err(wiegand_gpio->dev, "Couldn't register sysfs group\n");
+ return rc;
+ }
+
+ mutex_init(&wiegand_gpio->mutex);
+
+ misc_register(wiegand_gpio->misc_dev);
+ wiegand_gpio->misc_dev->parent = wiegand_gpio->dev;
+
+ memcpy(&wiegand_gpio->setup, &WIEGAND_SETUP,
+ sizeof(struct wiegand_setup));
+
+ dev_set_drvdata(device, wiegand_gpio);
+
+ return 0;
+}
+
+static int wiegand_gpio_dev_remove(struct device *device)
+{
+ struct wiegand_gpio_device *wiegand_gpio = dev_get_drvdata(device);
+
+ sysfs_remove_group(&wiegand_gpio->dev->kobj, &wiegand_group);
+
+ misc_deregister(&wiegand_misc_device);
+ kfree(wiegand_gpio);
+
+ return 0;
+}
+
+static const struct of_device_id wiegand_gpio_dt_idtable[] = {
+ { .compatible = "wiegand,wiegand-gpio", },
+ {},
+};
+MODULE_DEVICE_TABLE(of, wiegand_gpio_dt_idtable);
+
+static const enum wiegand_module_id wiegand_gpio_module_table[] = {
+ WIEGAND_MODULE_GPIO,
+ 0,
+};
+
+static struct wiegand_driver wiegand_gpio_driver = {
+ .driver = {
+ .name = "wiegand-gpio",
+ .probe = wiegand_gpio_dev_probe,
+ .remove = wiegand_gpio_dev_remove,
+ .of_match_table = wiegand_gpio_dt_idtable,
+ },
+ .id_table = wiegand_gpio_module_table,
+};
+
+module_wiegand_driver(wiegand_gpio_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Wiegand write-only driver realized by GPIOs");
+MODULE_AUTHOR("Martin Zaťovič <m.zatovic1@gmail.com>");
--
2.37.3
^ permalink raw reply related [flat|nested] 13+ messages in thread* Re: [RFCv2 PATCH 4/4] gpio: add Wiegand GPIO driver
2022-10-05 14:57 ` [RFCv2 PATCH 4/4] gpio: add Wiegand GPIO driver Martin Zaťovič
@ 2022-10-12 12:16 ` Bartosz Golaszewski
0 siblings, 0 replies; 13+ messages in thread
From: Bartosz Golaszewski @ 2022-10-12 12:16 UTC (permalink / raw)
To: Martin Zaťovič
Cc: robh+dt, krzysztof.kozlowski+dt, linus.walleij, gregkh,
jeffrey.l.hugo, andersson, Michael.Srba, saravanak, mani,
hemantk, linux-kernel, devicetree, linux-gpio
On Wed, Oct 5, 2022 at 4:58 PM Martin Zaťovič <m.zatovic1@gmail.com> wrote:
>
> Wiegand GPIO driver uses GPIO lines defined in the devicetree to
> transmit data following the Wiegand protocol.
>
> Signed-off-by: Martin Zaťovič <m.zatovic1@gmail.com>
> ---
[snip]
> +
> +DEVICE_ATTR_RW(pulse_len);
> +DEVICE_ATTR_RW(interval_len);
> +DEVICE_ATTR_RW(frame_gap);
> +DEVICE_ATTR_RW(format);
> +DEVICE_ATTR_RW(payload_len);
> +
We don't really allow GPIO drivers to define all kinds of custom
device attributes. Also: this driver does not register a GPIO provider
- rather it's a GPIO consumer.
For what you're trying to achieve: have you tried using libgpiod and
controlling the lines from user-space? If that's too slow, then I'd
say this driver should go somewhere else. Maybe you'd need a whole new
protocol sub-system for that. In any case - this subsystem is not the
right place.
Bartosz
[snip]
^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [RFCv2 PATCH 1/4] dt-bindings: bus: add Wiegand bus dt documentation
2022-10-05 14:57 [RFCv2 PATCH 1/4] dt-bindings: bus: add Wiegand bus dt documentation Martin Zaťovič
` (2 preceding siblings ...)
2022-10-05 14:57 ` [RFCv2 PATCH 4/4] gpio: add Wiegand GPIO driver Martin Zaťovič
@ 2022-10-06 2:18 ` Rob Herring
2022-10-06 8:25 ` Krzysztof Kozlowski
2022-10-06 8:33 ` Krzysztof Kozlowski
5 siblings, 0 replies; 13+ messages in thread
From: Rob Herring @ 2022-10-06 2:18 UTC (permalink / raw)
To: Martin Zaťovič
Cc: linus.walleij, krzysztof.kozlowski+dt, brgl, andersson, gregkh,
saravanak, mani, linux-kernel, linux-gpio, hemantk, devicetree,
Michael.Srba, robh+dt, jeffrey.l.hugo
[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain, Size: 2392 bytes --]
On Wed, 05 Oct 2022 16:57:43 +0200, Martin Zaťovič wrote:
> This patch documents the devicetree entry for enabling Wiegand
> bus driver. The drivers that will use Wiegand bus driver shall
> create a sub-node of the documented node.
>
> Signed-off-by: Martin Zaťovič <m.zatovic1@gmail.com>
> ---
> Hello again,
>
> this is the second round of RFC patches in an attempt to add Wiegand
> driver to linux kernel. Thank you for all the issues you have pointed
> out in the first round. I have tried to fix all of them and I have
> also implemented a Wiegand bus driver, that is now used by the GPIO
> driver itself - as suggested by Linus.
>
> Any advice you have for me regarding the patches will be appreciated!
>
> With regards,
> Martin Zaťovič
> ---
> .../devicetree/bindings/bus/wiegand.yaml | 50 +++++++++++++++++++
> 1 file changed, 50 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/bus/wiegand.yaml
>
My bot found errors running 'make DT_CHECKER_FLAGS=-m dt_binding_check'
on your patch (DT_CHECKER_FLAGS is new in v5.13):
yamllint warnings/errors:
dtschema/dtc warnings/errors:
/builds/robherring/dt-review-ci/linux/Documentation/devicetree/bindings/bus/wiegand.example.dtb: wiegand: 'wiegand-gpio' does not match any of the regexes: 'pinctrl-[0-9]+'
From schema: /builds/robherring/dt-review-ci/linux/Documentation/devicetree/bindings/bus/wiegand.yaml
/builds/robherring/dt-review-ci/linux/Documentation/devicetree/bindings/bus/wiegand.example.dtb: wiegand: wiegand-gpio: {'compatible': ['wiegand,wiegand-gpio'], 'pinctrl-names': ['default'], 'pinctrl-0': [[4294967295]], 'data-hi-gpios': [[4294967295, 7, 6]], 'data-lo-gpios': [[4294967295, 6, 6]]} is not of type 'array'
From schema: /usr/local/lib/python3.10/dist-packages/dtschema/schemas/gpio/gpio-consumer.yaml
Documentation/devicetree/bindings/bus/wiegand.example.dtb:0:0: /example-0/wiegand/wiegand-gpio: failed to match any schema with compatible: ['wiegand,wiegand-gpio']
doc reference errors (make refcheckdocs):
See https://patchwork.ozlabs.org/patch/
This check can fail if there are any dependencies. The base for a patch
series is generally the most recent rc1.
If you already ran 'make dt_binding_check' and didn't see the above
error(s), then make sure 'yamllint' is installed and dt-schema is up to
date:
pip3 install dtschema --upgrade
Please check and re-submit.
^ permalink raw reply [flat|nested] 13+ messages in thread* Re: [RFCv2 PATCH 1/4] dt-bindings: bus: add Wiegand bus dt documentation
2022-10-05 14:57 [RFCv2 PATCH 1/4] dt-bindings: bus: add Wiegand bus dt documentation Martin Zaťovič
` (3 preceding siblings ...)
2022-10-06 2:18 ` [RFCv2 PATCH 1/4] dt-bindings: bus: add Wiegand bus dt documentation Rob Herring
@ 2022-10-06 8:25 ` Krzysztof Kozlowski
2022-10-06 8:33 ` Krzysztof Kozlowski
5 siblings, 0 replies; 13+ messages in thread
From: Krzysztof Kozlowski @ 2022-10-06 8:25 UTC (permalink / raw)
To: Martin Zaťovič,
robh+dt, krzysztof.kozlowski+dt, linus.walleij, brgl, gregkh,
jeffrey.l.hugo, andersson, Michael.Srba, saravanak, mani,
hemantk, linux-kernel, devicetree, linux-gpio
On 05/10/2022 16:57, Martin Zaťovič wrote:
> This patch documents the devicetree entry for enabling Wiegand
> bus driver. The drivers that will use Wiegand bus driver shall
> create a sub-node of the documented node.
>
> Signed-off-by: Martin Zaťovič <m.zatovic1@gmail.com>
> ---
> Hello again,
>
> this is the second round of RFC patches in an attempt to add Wiegand
> driver to linux kernel. Thank you for all the issues you have pointed
> out in the first round. I have tried to fix all of them and I have
> also implemented a Wiegand bus driver, that is now used by the GPIO
> driver itself - as suggested by Linus.
>
> Any advice you have for me regarding the patches will be appreciated!
>
> With regards,
> Martin Zaťovič
> ---
> .../devicetree/bindings/bus/wiegand.yaml | 50 +++++++++++++++++++
> 1 file changed, 50 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/bus/wiegand.yaml
>
> diff --git a/Documentation/devicetree/bindings/bus/wiegand.yaml b/Documentation/devicetree/bindings/bus/wiegand.yaml
> new file mode 100644
> index 000000000000..1ed863ab925c
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/bus/wiegand.yaml
> @@ -0,0 +1,50 @@
> +# SPDX-License-Identifier: GPL-2.0
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/bus/wiegand.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Wiegand Bus
> +
> +maintainers:
> + - Martin Zaťovič <m.zatovic1@gmail.com>
> +
> +description: |
> + Wiegand interface is a wiring standard popularized in the 1980s. To this day
> + many card readers, fingerprint readers, sensors, etc. use Wiegand interface
> + particularly for access control applications. It utilizes two wires to
> + transmit the data - D0 and D1.
> +
> + Both data lines are initially pulled up. To send a bit of value 1, the D1
> + line is set low. Similarly to send a bit of value 0, the D0 line is set low.
> +
> +properties:
> + $nodename:
> + pattern: "^wiegand(@[0-9a-f]+)?$"
> +
> + compatible:
> + contains:
> + const: wiegand
> +
If the bus uses two wires, shouldn't you describe them here? Otherwise
what wires are you using?
> +required:
> + - compatible
> +
> +additionalProperties: false
> +
> +examples:
> + - |
> + #include <dt-bindings/gpio/gpio.h>
> +
> + wiegand {
> + compatible = "wiegand";
> +
> + wiegand-gpio {
> + compatible = "wiegand,wiegand-gpio";
> + pinctrl-names = "default";
> + pinctrl-0 = <&pinctrl_uart2_wiegand>;
> + data-hi-gpios = <&gpio 7 (GPIO_ACTIVE_HIGH|GPIO_OPEN_DRAIN)>;
> + data-lo-gpios = <&gpio 6 (GPIO_ACTIVE_HIGH|GPIO_OPEN_DRAIN)>;
> + };
> + };
> +
> +...
Best regards,
Krzysztof
^ permalink raw reply [flat|nested] 13+ messages in thread* Re: [RFCv2 PATCH 1/4] dt-bindings: bus: add Wiegand bus dt documentation
2022-10-05 14:57 [RFCv2 PATCH 1/4] dt-bindings: bus: add Wiegand bus dt documentation Martin Zaťovič
` (4 preceding siblings ...)
2022-10-06 8:25 ` Krzysztof Kozlowski
@ 2022-10-06 8:33 ` Krzysztof Kozlowski
5 siblings, 0 replies; 13+ messages in thread
From: Krzysztof Kozlowski @ 2022-10-06 8:33 UTC (permalink / raw)
To: Martin Zaťovič,
robh+dt, krzysztof.kozlowski+dt, linus.walleij, brgl, gregkh,
jeffrey.l.hugo, andersson, Michael.Srba, saravanak, mani,
hemantk, linux-kernel, devicetree, linux-gpio
On 05/10/2022 16:57, Martin Zaťovič wrote:
> This patch documents the devicetree entry for enabling Wiegand
> bus driver. The drivers that will use Wiegand bus driver shall
> create a sub-node of the documented node.
>
> Signed-off-by: Martin Zaťovič <m.zatovic1@gmail.com>
> ---
> Hello again,
>
Missing cover letter and changelog.
Best regards,
Krzysztof
^ permalink raw reply [flat|nested] 13+ messages in thread