From: Jonathan Cameron <jic23@kernel.org>
To: William Breathitt Gray <vilhelm.gray@gmail.com>
Cc: kernel@pengutronix.de, linux-stm32@st-md-mailman.stormreply.com,
a.fatoum@pengutronix.de, kamel.bouhara@bootlin.com,
gwendal@chromium.org, alexandre.belloni@bootlin.com,
david@lechnology.com, linux-iio@vger.kernel.org,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, syednwaris@gmail.com,
patrick.havelange@essensium.com, fabrice.gasnier@st.com,
mcoquelin.stm32@gmail.com, alexandre.torgue@st.com,
o.rempel@pengutronix.de, Dan Carpenter <dan.carpenter@oracle.com>
Subject: Re: [PATCH v8 17/22] counter: Add character device interface
Date: Sun, 14 Feb 2021 18:06:12 +0000 [thread overview]
Message-ID: <20210214180612.03af6f0d@archlinux> (raw)
In-Reply-To: <720278e3aaf3f249657ec18d158eca3f962baf8e.1613131238.git.vilhelm.gray@gmail.com>
On Fri, 12 Feb 2021 21:13:41 +0900
William Breathitt Gray <vilhelm.gray@gmail.com> wrote:
> This patch introduces a character device interface for the Counter
> subsystem. Device data is exposed through standard character device read
> operations. Device data is gathered when a Counter event is pushed by
> the respective Counter device driver. Configuration is handled via ioctl
> operations on the respective Counter character device node.
>
> Cc: David Lechner <david@lechnology.com>
> Cc: Gwendal Grignou <gwendal@chromium.org>
> Cc: Dan Carpenter <dan.carpenter@oracle.com>
> Cc: Oleksij Rempel <o.rempel@pengutronix.de>
> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Hi William,
A few minor comments. Mostly seems to have come together well and
makes sense to me.
Jonathan
> ---
> drivers/counter/Makefile | 2 +-
> drivers/counter/counter-chrdev.c | 496 +++++++++++++++++++++++++++++++
> drivers/counter/counter-chrdev.h | 16 +
> drivers/counter/counter-core.c | 37 ++-
> include/linux/counter.h | 45 +++
> include/uapi/linux/counter.h | 70 +++++
> 6 files changed, 661 insertions(+), 5 deletions(-)
> create mode 100644 drivers/counter/counter-chrdev.c
> create mode 100644 drivers/counter/counter-chrdev.h
>
...
> diff --git a/drivers/counter/counter-core.c b/drivers/counter/counter-core.c
> index bcf672e1fc0d..c137fcb97d9c 100644
> --- a/drivers/counter/counter-core.c
> +++ b/drivers/counter/counter-core.c
> @@ -5,12 +5,16 @@
> */
> #include <linux/counter.h>
> #include <linux/device.h>
> +#include <linux/device/bus.h>
> #include <linux/export.h>
> +#include <linux/fs.h>
> #include <linux/gfp.h>
> #include <linux/idr.h>
> #include <linux/init.h>
> #include <linux/module.h>
> +#include <linux/types.h>
>
> +#include "counter-chrdev.h"
> #include "counter-sysfs.h"
>
> /* Provides a unique ID for each counter device */
> @@ -33,6 +37,8 @@ static struct bus_type counter_bus_type = {
> .name = "counter"
> };
>
> +static dev_t counter_devt;
> +
> /**
> * counter_register - register Counter to the system
> * @counter: pointer to Counter to register
> @@ -54,7 +60,6 @@ int counter_register(struct counter_device *const counter)
> if (counter->id < 0)
> return counter->id;
>
> - /* Configure device structure for Counter */
Not sure why this comment gets removed here.
> dev->type = &counter_device_type;
> dev->bus = &counter_bus_type;
> if (counter->parent) {
> @@ -65,18 +70,25 @@ int counter_register(struct counter_device *const counter)
> device_initialize(dev);
> dev_set_drvdata(dev, counter);
>
> + /* Add Counter character device */
> + err = counter_chrdev_add(counter, counter_devt);
> + if (err < 0)
> + goto err_free_id;
> +
> /* Add Counter sysfs attributes */
> err = counter_sysfs_add(counter);
> if (err < 0)
> - goto err_free_id;
> + goto err_remove_chrdev;
>
> /* Add device to system */
> err = device_add(dev);
> if (err < 0)
> - goto err_free_id;
> + goto err_remove_chrdev;
It might be worth thinking about using cdev_device_add()
though will require a slightly different order of adding.
>
> return 0;
>
> +err_remove_chrdev:
> + counter_chrdev_remove(counter);
> err_free_id:
> put_device(dev);
> return err;
> @@ -138,13 +150,30 @@ int devm_counter_register(struct device *dev,
> }
> EXPORT_SYMBOL_GPL(devm_counter_register);
>
> +#define COUNTER_DEV_MAX 256
> +
> static int __init counter_init(void)
> {
> - return bus_register(&counter_bus_type);
> + int err;
> +
> + err = bus_register(&counter_bus_type);
> + if (err < 0)
> + return err;
> +
> + err = alloc_chrdev_region(&counter_devt, 0, COUNTER_DEV_MAX, "counter");
> + if (err < 0)
> + goto err_unregister_bus;
> +
> + return 0;
> +
> +err_unregister_bus:
> + bus_unregister(&counter_bus_type);
> + return err;
> }
>
> static void __exit counter_exit(void)
> {
> + unregister_chrdev_region(counter_devt, COUNTER_DEV_MAX);
> bus_unregister(&counter_bus_type);
> }
>
...
> diff --git a/include/uapi/linux/counter.h b/include/uapi/linux/counter.h
> index 6113938a6044..3d647a5383b8 100644
> --- a/include/uapi/linux/counter.h
> +++ b/include/uapi/linux/counter.h
> @@ -6,6 +6,19 @@
> #ifndef _UAPI_COUNTER_H_
> #define _UAPI_COUNTER_H_
>
> +#include <linux/ioctl.h>
> +#include <linux/types.h>
> +
> +/* Component type definitions */
> +enum counter_component_type {
> + COUNTER_COMPONENT_NONE,
> + COUNTER_COMPONENT_SIGNAL,
> + COUNTER_COMPONENT_COUNT,
> + COUNTER_COMPONENT_FUNCTION,
> + COUNTER_COMPONENT_SYNAPSE_ACTION,
> + COUNTER_COMPONENT_EXTENSION,
> +};
> +
> /* Component scope definitions */
> enum counter_scope {
> COUNTER_SCOPE_DEVICE,
> @@ -13,6 +26,63 @@ enum counter_scope {
> COUNTER_SCOPE_COUNT,
> };
>
> +/**
> + * struct counter_component - Counter component identification
> + * @type: component type (one of enum counter_component_type)
> + * @scope: component scope (one of enum counter_scope)
> + * @parent: parent component ID (matching the Y/Z suffix of the respective sysfs
> + * path as described in Documentation/ABI/testing/sysfs-bus-counter)
Probably good to give an example here as well as the cross reference.
> + * @id: component ID (matching the Y/Z suffix of the respective sysfs path as
> + * described in Documentation/ABI/testing/sysfs-bus-counter)
> + */
> +struct counter_component {
> + __u8 type;
> + __u8 scope;
> + __u8 parent;
> + __u8 id;
> +};
> +
> +/* Event type definitions */
> +enum counter_event_type {
> + COUNTER_EVENT_OVERFLOW,
> + COUNTER_EVENT_UNDERFLOW,
> + COUNTER_EVENT_OVERFLOW_UNDERFLOW,
> + COUNTER_EVENT_THRESHOLD,
> + COUNTER_EVENT_INDEX,
> +};
> +
> +/**
> + * struct counter_watch - Counter component watch configuration
> + * @component: component to watch when event triggers
> + * @event: event that triggers (one of enum counter_event_type)
> + * @channel: event channel (typically 0 unless the device supports concurrent
> + * events of the same type)
> + */
> +struct counter_watch {
> + struct counter_component component;
> + __u8 event;
> + __u8 channel;
> +};
> +
> +/* ioctl commands */
> +#define COUNTER_ADD_WATCH_IOCTL _IOW(0x3E, 0x00, struct counter_watch)
> +#define COUNTER_ENABLE_EVENTS_IOCTL _IO(0x3E, 0x01)
> +#define COUNTER_DISABLE_EVENTS_IOCTL _IO(0x3E, 0x02)
> +
> +/**
> + * struct counter_event - Counter event data
> + * @timestamp: best estimate of time of event occurrence, in nanoseconds
> + * @value: component value
> + * @watch: component watch configuration
> + * @status: return status (system error number)
> + */
> +struct counter_event {
> + __aligned_u64 timestamp;
> + __aligned_u64 value;
> + struct counter_watch watch;
> + __u8 status;
> +};
> +
> /* Count direction values */
> enum counter_count_direction {
> COUNTER_COUNT_DIRECTION_FORWARD,
next prev parent reply other threads:[~2021-02-14 18:07 UTC|newest]
Thread overview: 70+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-12 12:13 [PATCH v8 00/22] Introduce the Counter character device interface William Breathitt Gray
2021-02-12 12:13 ` [PATCH v8 01/22] docs: counter: Consolidate Counter sysfs attributes documentation William Breathitt Gray
2021-02-14 16:57 ` Jonathan Cameron
2021-02-15 11:05 ` William Breathitt Gray
2021-02-20 16:25 ` David Lechner
2021-02-12 12:13 ` [PATCH v8 02/22] docs: counter: Fix spelling William Breathitt Gray
2021-02-20 16:26 ` David Lechner
2021-02-12 12:13 ` [PATCH v8 03/22] counter: 104-quad-8: Return error when invalid mode during ceiling_write William Breathitt Gray
2021-02-20 16:30 ` David Lechner
2021-02-22 2:06 ` William Breathitt Gray
2021-02-12 12:13 ` [PATCH v8 04/22] counter: 104-quad-8: Annotate hardware config module parameter William Breathitt Gray
2021-02-12 12:13 ` [PATCH v8 05/22] counter: 104-quad-8: Add const qualifiers for quad8_preset_register_set William Breathitt Gray
2021-02-12 12:13 ` [PATCH v8 06/22] counter: 104-quad-8: Add const qualifier for functions_list array William Breathitt Gray
2021-02-12 12:13 ` [PATCH v8 07/22] counter: 104-quad-8: Add const qualifier for actions_list array William Breathitt Gray
2021-02-12 12:13 ` [PATCH v8 08/22] counter: ftm-quaddec: " William Breathitt Gray
2021-02-12 12:13 ` [PATCH v8 09/22] counter: Return error code on invalid modes William Breathitt Gray
2021-02-14 17:07 ` Jonathan Cameron
2021-02-20 16:43 ` David Lechner
2021-02-22 4:42 ` William Breathitt Gray
2021-02-12 12:13 ` [PATCH v8 10/22] counter: Standardize to ERANGE for limit exceeded errors William Breathitt Gray
2021-02-14 17:10 ` Jonathan Cameron
2021-02-16 1:26 ` William Breathitt Gray
2021-02-21 14:03 ` Jonathan Cameron
2021-02-20 16:48 ` David Lechner
2021-02-12 12:13 ` [PATCH v8 11/22] counter: Rename counter_signal_value to counter_signal_level William Breathitt Gray
2021-02-20 16:52 ` David Lechner
2021-02-12 12:13 ` [PATCH v8 12/22] counter: Rename counter_count_function to counter_function William Breathitt Gray
2021-02-14 17:13 ` Jonathan Cameron
2021-02-20 16:56 ` David Lechner
2021-02-23 5:14 ` William Breathitt Gray
2021-02-12 12:13 ` [PATCH v8 13/22] counter: Internalize sysfs interface code William Breathitt Gray
2021-02-14 17:32 ` Jonathan Cameron
2021-02-20 17:50 ` David Lechner
2021-02-12 12:13 ` [PATCH v8 14/22] counter: Update counter.h comments to reflect sysfs internalization William Breathitt Gray
2021-02-12 12:13 ` [PATCH v8 15/22] docs: counter: Update " William Breathitt Gray
2021-02-12 12:13 ` [PATCH v8 16/22] counter: Move counter enums to uapi header William Breathitt Gray
2021-02-20 23:55 ` David Lechner
2021-02-12 12:13 ` [PATCH v8 17/22] counter: Add character device interface William Breathitt Gray
2021-02-14 18:06 ` Jonathan Cameron [this message]
2021-02-24 5:34 ` William Breathitt Gray
2021-02-15 9:24 ` Oleksij Rempel
2021-02-16 1:53 ` William Breathitt Gray
2021-02-12 12:13 ` [PATCH v8 18/22] docs: counter: Document " William Breathitt Gray
2021-02-14 17:48 ` Jonathan Cameron
2021-02-22 10:11 ` Pavel Machek
2021-02-26 0:27 ` William Breathitt Gray
2021-02-26 0:22 ` William Breathitt Gray
2021-02-12 12:13 ` [PATCH v8 19/22] counter: Implement extension*_name sysfs attributes William Breathitt Gray
2021-02-14 18:09 ` Jonathan Cameron
2021-02-19 8:51 ` William Breathitt Gray
2021-02-21 14:05 ` Jonathan Cameron
2021-02-25 23:32 ` William Breathitt Gray
2021-02-27 15:14 ` Jonathan Cameron
2021-02-12 12:13 ` [PATCH v8 20/22] counter: Implement events_queue_size sysfs attribute William Breathitt Gray
2021-02-14 18:11 ` Jonathan Cameron
2021-02-18 10:32 ` William Breathitt Gray
2021-02-21 15:51 ` Jonathan Cameron
2021-02-26 0:03 ` William Breathitt Gray
2021-02-27 0:14 ` David Lechner
2021-02-27 0:20 ` William Breathitt Gray
2021-02-27 15:18 ` Jonathan Cameron
2021-02-28 2:46 ` William Breathitt Gray
2021-02-12 12:13 ` [PATCH v8 21/22] counter: 104-quad-8: Replace mutex with spinlock William Breathitt Gray
2021-02-14 18:19 ` Jonathan Cameron
2021-02-16 2:16 ` William Breathitt Gray
2021-02-16 19:27 ` Jonathan Cameron
2021-02-18 10:16 ` William Breathitt Gray
2021-02-12 12:13 ` [PATCH v8 22/22] counter: 104-quad-8: Add IRQ support for the ACCES 104-QUAD-8 William Breathitt Gray
2021-02-14 18:24 ` Jonathan Cameron
2021-02-19 9:21 ` William Breathitt Gray
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