From 3b51c44bd6936e86a7180abd9aebc4387a479253 Mon Sep 17 00:00:00 2001 From: Atif Niyaz Date: Wed, 24 Jul 2019 22:26:31 +0300 Subject: Input: allow drivers specify timestamp for input events Currently, evdev stamps events with timestamps acquired in evdev_events() However, this timestamping may not be accurate in terms of measuring when the actual event happened. Let's allow individual drivers specify timestamp in order to provide a more accurate sense of time for the event. It is expected that drivers will set the timestamp in their hard interrupt routine. Signed-off-by: Atif Niyaz Signed-off-by: Dmitry Torokhov --- drivers/input/evdev.c | 35 ++++++++--------------------------- drivers/input/input.c | 40 ++++++++++++++++++++++++++++++++++++++++ include/linux/input.h | 14 ++++++++++++++ 3 files changed, 62 insertions(+), 27 deletions(-) diff --git a/drivers/input/evdev.c b/drivers/input/evdev.c index 867c2cfd0038..d7dd6fcf2db0 100644 --- a/drivers/input/evdev.c +++ b/drivers/input/evdev.c @@ -25,13 +25,6 @@ #include #include "input-compat.h" -enum evdev_clock_type { - EV_CLK_REAL = 0, - EV_CLK_MONO, - EV_CLK_BOOT, - EV_CLK_MAX -}; - struct evdev { int open; struct input_handle handle; @@ -53,7 +46,7 @@ struct evdev_client { struct fasync_struct *fasync; struct evdev *evdev; struct list_head node; - unsigned int clk_type; + enum input_clock_type clk_type; bool revoked; unsigned long *evmasks[EV_CNT]; unsigned int bufsize; @@ -149,17 +142,10 @@ static void __evdev_flush_queue(struct evdev_client *client, unsigned int type) static void __evdev_queue_syn_dropped(struct evdev_client *client) { + ktime_t *ev_time = input_get_timestamp(client->evdev->handle.dev); + struct timespec64 ts = ktime_to_timespec64(ev_time[client->clk_type]); struct input_event ev; - ktime_t time; - struct timespec64 ts; - time = client->clk_type == EV_CLK_REAL ? - ktime_get_real() : - client->clk_type == EV_CLK_MONO ? - ktime_get() : - ktime_get_boottime(); - - ts = ktime_to_timespec64(time); ev.input_event_sec = ts.tv_sec; ev.input_event_usec = ts.tv_nsec / NSEC_PER_USEC; ev.type = EV_SYN; @@ -188,18 +174,18 @@ static void evdev_queue_syn_dropped(struct evdev_client *client) static int evdev_set_clk_type(struct evdev_client *client, unsigned int clkid) { unsigned long flags; - unsigned int clk_type; + enum input_clock_type clk_type; switch (clkid) { case CLOCK_REALTIME: - clk_type = EV_CLK_REAL; + clk_type = INPUT_CLK_REAL; break; case CLOCK_MONOTONIC: - clk_type = EV_CLK_MONO; + clk_type = INPUT_CLK_MONO; break; case CLOCK_BOOTTIME: - clk_type = EV_CLK_BOOT; + clk_type = INPUT_CLK_BOOT; break; default: return -EINVAL; @@ -307,12 +293,7 @@ static void evdev_events(struct input_handle *handle, { struct evdev *evdev = handle->private; struct evdev_client *client; - ktime_t ev_time[EV_CLK_MAX]; - - ev_time[EV_CLK_MONO] = ktime_get(); - ev_time[EV_CLK_REAL] = ktime_mono_to_real(ev_time[EV_CLK_MONO]); - ev_time[EV_CLK_BOOT] = ktime_mono_to_any(ev_time[EV_CLK_MONO], - TK_OFFS_BOOT); + ktime_t *ev_time = input_get_timestamp(handle->dev); rcu_read_lock(); diff --git a/drivers/input/input.c b/drivers/input/input.c index 7f3c5fcb9ed6..7494a0dede79 100644 --- a/drivers/input/input.c +++ b/drivers/input/input.c @@ -1894,6 +1894,46 @@ void input_free_device(struct input_dev *dev) } EXPORT_SYMBOL(input_free_device); +/** + * input_set_timestamp - set timestamp for input events + * @dev: input device to set timestamp for + * @timestamp: the time at which the event has occurred + * in CLOCK_MONOTONIC + * + * This function is intended to provide to the input system a more + * accurate time of when an event actually occurred. The driver should + * call this function as soon as a timestamp is acquired ensuring + * clock conversions in input_set_timestamp are done correctly. + * + * The system entering suspend state between timestamp acquisition and + * calling input_set_timestamp can result in inaccurate conversions. + */ +void input_set_timestamp(struct input_dev *dev, ktime_t timestamp) +{ + dev->timestamp[INPUT_CLK_MONO] = timestamp; + dev->timestamp[INPUT_CLK_REAL] = ktime_mono_to_real(timestamp); + dev->timestamp[INPUT_CLK_BOOT] = ktime_mono_to_any(timestamp, + TK_OFFS_BOOT); +} +EXPORT_SYMBOL(input_set_timestamp); + +/** + * input_get_timestamp - get timestamp for input events + * @dev: input device to get timestamp from + * + * A valid timestamp is a timestamp of non-zero value. + */ +ktime_t *input_get_timestamp(struct input_dev *dev) +{ + const ktime_t invalid_timestamp = ktime_set(0, 0); + + if (!ktime_compare(dev->timestamp[INPUT_CLK_MONO], invalid_timestamp)) + input_set_timestamp(dev, ktime_get()); + + return dev->timestamp; +} +EXPORT_SYMBOL(input_get_timestamp); + /** * input_set_capability - mark device as capable of a certain event * @dev: device that is capable of emitting or accepting event diff --git a/include/linux/input.h b/include/linux/input.h index 510e78558c10..e95a439d8bd5 100644 --- a/include/linux/input.h +++ b/include/linux/input.h @@ -33,6 +33,13 @@ struct input_value { __s32 value; }; +enum input_clock_type { + INPUT_CLK_REAL = 0, + INPUT_CLK_MONO, + INPUT_CLK_BOOT, + INPUT_CLK_MAX +}; + /** * struct input_dev - represents an input device * @name: name of the device @@ -114,6 +121,8 @@ struct input_value { * @vals: array of values queued in the current frame * @devres_managed: indicates that devices is managed with devres framework * and needs not be explicitly unregistered or freed. + * @timestamp: storage for a timestamp set by input_set_timestamp called + * by a driver */ struct input_dev { const char *name; @@ -184,6 +193,8 @@ struct input_dev { struct input_value *vals; bool devres_managed; + + ktime_t timestamp[INPUT_CLK_MAX]; }; #define to_input_dev(d) container_of(d, struct input_dev, dev) @@ -382,6 +393,9 @@ void input_close_device(struct input_handle *); int input_flush_device(struct input_handle *handle, struct file *file); +void input_set_timestamp(struct input_dev *dev, ktime_t timestamp); +ktime_t *input_get_timestamp(struct input_dev *dev); + void input_event(struct input_dev *dev, unsigned int type, unsigned int code, int value); void input_inject_event(struct input_handle *handle, unsigned int type, unsigned int code, int value); -- cgit