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Tue, 15 Oct 2024 03:56:37 -0700 (PDT) From: Bartosz Golaszewski Date: Tue, 15 Oct 2024 12:56:18 +0200 Subject: [PATCH v3 6/6] gpiolib: notify user-space about in-kernel line state changes Precedence: bulk X-Mailing-List: linux-gpio@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20241015-gpio-notify-in-kernel-events-v3-6-9edf05802271@linaro.org> References: <20241015-gpio-notify-in-kernel-events-v3-0-9edf05802271@linaro.org> In-Reply-To: <20241015-gpio-notify-in-kernel-events-v3-0-9edf05802271@linaro.org> To: Linus Walleij , Bartosz Golaszewski , Kent Gibson Cc: linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org, Bartosz Golaszewski X-Mailer: b4 0.13.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=7877; i=bartosz.golaszewski@linaro.org; h=from:subject:message-id; bh=ePQ3NHmW799l+7FWll3i7+jrGwxa4SiDEOy93jWL4Mg=; b=owEBbQKS/ZANAwAKARGnLqAUcddyAcsmYgBnDkpfGeH1iFc5qP7f9JLNiUYAs12V185a8duPl 9uc5wXnvYeJAjMEAAEKAB0WIQQWnetsC8PEYBPSx58Rpy6gFHHXcgUCZw5KXwAKCRARpy6gFHHX cuckD/43OV4paP5znbk19rt07BJUmCyQe78m0AZFagLlQ9CibdcxoXAFh6lObSZxz6pshvthQ5G 7Z69tOPXueqtYRhVQLD52Z2nw2puiBCpmHDMLnsOO9Y4ZfJdrXYG6P3HXf5Fpf6s+xgoquUtGhj DKdnvisZDH5jZdsfxCbhFknQ5ORR2s6VUK3pxRTCcrHI7n8vObqRpZtKAUwJv21UNPoB21Vd1Dj wPv+TX/CuxUWvttrkcXqOu6vLsnwnagYyjrCgUTB4aFcf4jEx52GKHIajQrgZeVAcPAbmEXNtOn 0c3TL6+VV/wxVosNGNk+zkcg0TvPx5gIKFkwO1DGzr1arYeFSFsP4fIIsob9FwAwM49ybJM6s08 tsSGRWT7ZL0hSeirsrWMn41uSk+tKBEql5YJBxnvrGdBfHpVIMl+xNZ74/PHsnqozJLL0TFsMiu dnCrOiUBk2k5MXELo4io9HGuv2wwU77zF/iUgBEhFj5m2kt/R/7q7Ha7W58kMOqlNd7cybeY+tQ QSP902mbwJ/wMTSdxUaZWIg1xlLFHaTFA5PrlWNLaU7pEuD8o4wIbhNWztl/hvNbmkDWfi/7w1i Nv3EwTsloDKJ7p7uHv+h42R+qwRVxq5qjBmTPSfuGJp5U76mngTR1rguchSklS8wH3fGgm92R8E MLhl9ASXI76L8fQ== X-Developer-Key: i=bartosz.golaszewski@linaro.org; a=openpgp; fpr=169DEB6C0BC3C46013D2C79F11A72EA01471D772 From: Bartosz Golaszewski We currently only notify user-space about line config changes that are made from user-space. Any kernel config changes are not signalled. Let's improve the situation by emitting the events closer to the source. To that end let's call the relevant notifier chain from the functions setting direction, gpiod_set_config(), gpiod_set_consumer_name() and gpiod_toggle_active_low(). This covers all the options that we can inform the user-space about. We ignore events which don't have corresponding flags exported to user-space on purpose - otherwise the user would see a config-changed event but the associated line-info would remain unchanged. gpiod_direction_output/input() can be called from any context. Fortunately, we now emit line state events using an atomic notifier chain, so it's no longer an issue. Let's also add non-notifying wrappers around the direction setters in order to not emit superfluous reconfigure events when requesting the lines as the initial config should be part of the request notification. Signed-off-by: Bartosz Golaszewski --- drivers/gpio/gpiolib-cdev.c | 12 +++----- drivers/gpio/gpiolib.c | 71 ++++++++++++++++++++++++++++++++++++++++----- drivers/gpio/gpiolib.h | 2 ++ 3 files changed, 70 insertions(+), 15 deletions(-) diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c index f8c69ef33888..1296e6cbcef7 100644 --- a/drivers/gpio/gpiolib-cdev.c +++ b/drivers/gpio/gpiolib-cdev.c @@ -196,8 +196,6 @@ static long linehandle_set_config(struct linehandle_state *lh, if (ret) return ret; } - - gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_CONFIG); } return 0; } @@ -363,11 +361,11 @@ static int linehandle_create(struct gpio_device *gdev, void __user *ip) if (lflags & GPIOHANDLE_REQUEST_OUTPUT) { int val = !!handlereq.default_values[i]; - ret = gpiod_direction_output(desc, val); + ret = gpiod_direction_output_nonotify(desc, val); if (ret) goto out_free_lh; } else if (lflags & GPIOHANDLE_REQUEST_INPUT) { - ret = gpiod_direction_input(desc); + ret = gpiod_direction_input_nonotify(desc); if (ret) goto out_free_lh; } @@ -1568,8 +1566,6 @@ static long linereq_set_config(struct linereq *lr, void __user *ip) } WRITE_ONCE(line->edflags, edflags); - - gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_CONFIG); } return 0; } @@ -1826,11 +1822,11 @@ static int linereq_create(struct gpio_device *gdev, void __user *ip) if (flags & GPIO_V2_LINE_FLAG_OUTPUT) { int val = gpio_v2_line_config_output_value(lc, i); - ret = gpiod_direction_output(desc, val); + ret = gpiod_direction_output_nonotify(desc, val); if (ret) goto out_free_linereq; } else if (flags & GPIO_V2_LINE_FLAG_INPUT) { - ret = gpiod_direction_input(desc); + ret = gpiod_direction_input_nonotify(desc); if (ret) goto out_free_linereq; diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index fafa759ce743..4303b6a689af 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -2673,6 +2673,18 @@ int gpio_set_debounce_timeout(struct gpio_desc *desc, unsigned int debounce) * 0 on success, or negative errno on failure. */ int gpiod_direction_input(struct gpio_desc *desc) +{ + int ret; + + ret = gpiod_direction_input_nonotify(desc); + if (ret == 0) + gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_CONFIG); + + return ret; +} +EXPORT_SYMBOL_GPL(gpiod_direction_input); + +int gpiod_direction_input_nonotify(struct gpio_desc *desc) { int ret = 0; @@ -2720,7 +2732,6 @@ int gpiod_direction_input(struct gpio_desc *desc) return ret; } -EXPORT_SYMBOL_GPL(gpiod_direction_input); static int gpiod_direction_output_raw_commit(struct gpio_desc *desc, int value) { @@ -2782,8 +2793,15 @@ static int gpiod_direction_output_raw_commit(struct gpio_desc *desc, int value) */ int gpiod_direction_output_raw(struct gpio_desc *desc, int value) { + int ret; + VALIDATE_DESC(desc); - return gpiod_direction_output_raw_commit(desc, value); + + ret = gpiod_direction_output_raw_commit(desc, value); + if (ret == 0) + gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_CONFIG); + + return ret; } EXPORT_SYMBOL_GPL(gpiod_direction_output_raw); @@ -2801,6 +2819,18 @@ EXPORT_SYMBOL_GPL(gpiod_direction_output_raw); * 0 on success, or negative errno on failure. */ int gpiod_direction_output(struct gpio_desc *desc, int value) +{ + int ret; + + ret = gpiod_direction_output_nonotify(desc, value); + if (ret == 0) + gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_CONFIG); + + return ret; +} +EXPORT_SYMBOL_GPL(gpiod_direction_output); + +int gpiod_direction_output_nonotify(struct gpio_desc *desc, int value) { unsigned long flags; int ret; @@ -2863,7 +2893,6 @@ int gpiod_direction_output(struct gpio_desc *desc, int value) set_bit(FLAG_IS_OUT, &desc->flags); return ret; } -EXPORT_SYMBOL_GPL(gpiod_direction_output); /** * gpiod_enable_hw_timestamp_ns - Enable hardware timestamp in nanoseconds. @@ -2942,13 +2971,34 @@ EXPORT_SYMBOL_GPL(gpiod_disable_hw_timestamp_ns); */ int gpiod_set_config(struct gpio_desc *desc, unsigned long config) { + int ret; + VALIDATE_DESC(desc); CLASS(gpio_chip_guard, guard)(desc); if (!guard.gc) return -ENODEV; - return gpio_do_set_config(guard.gc, gpio_chip_hwgpio(desc), config); + ret = gpio_do_set_config(guard.gc, gpio_chip_hwgpio(desc), config); + if (ret == 0) { + /* These are the only options we notify the userspace about. */ + switch (pinconf_to_config_param(config)) { + case PIN_CONFIG_BIAS_DISABLE: + case PIN_CONFIG_BIAS_PULL_DOWN: + case PIN_CONFIG_BIAS_PULL_UP: + case PIN_CONFIG_DRIVE_OPEN_DRAIN: + case PIN_CONFIG_DRIVE_OPEN_SOURCE: + case PIN_CONFIG_DRIVE_PUSH_PULL: + case PIN_CONFIG_INPUT_DEBOUNCE: + gpiod_line_state_notify(desc, + GPIO_V2_LINE_CHANGED_CONFIG); + break; + default: + break; + } + } + + return ret; } EXPORT_SYMBOL_GPL(gpiod_set_config); @@ -3015,6 +3065,7 @@ void gpiod_toggle_active_low(struct gpio_desc *desc) { VALIDATE_DESC_VOID(desc); change_bit(FLAG_ACTIVE_LOW, &desc->flags); + gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_CONFIG); } EXPORT_SYMBOL_GPL(gpiod_toggle_active_low); @@ -3659,9 +3710,15 @@ EXPORT_SYMBOL_GPL(gpiod_cansleep); */ int gpiod_set_consumer_name(struct gpio_desc *desc, const char *name) { + int ret; + VALIDATE_DESC(desc); - return desc_set_label(desc, name); + ret = desc_set_label(desc, name); + if (ret == 0) + gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_CONFIG); + + return ret; } EXPORT_SYMBOL_GPL(gpiod_set_consumer_name); @@ -4539,10 +4596,10 @@ int gpiod_configure_flags(struct gpio_desc *desc, const char *con_id, /* Process flags */ if (dflags & GPIOD_FLAGS_BIT_DIR_OUT) - ret = gpiod_direction_output(desc, + ret = gpiod_direction_output_nonotify(desc, !!(dflags & GPIOD_FLAGS_BIT_DIR_VAL)); else - ret = gpiod_direction_input(desc); + ret = gpiod_direction_input_nonotify(desc); return ret; } diff --git a/drivers/gpio/gpiolib.h b/drivers/gpio/gpiolib.h index 2799157a1f6b..fc321d281346 100644 --- a/drivers/gpio/gpiolib.h +++ b/drivers/gpio/gpiolib.h @@ -155,6 +155,8 @@ int gpiod_set_array_value_complex(bool raw, bool can_sleep, int gpiod_set_transitory(struct gpio_desc *desc, bool transitory); void gpiod_line_state_notify(struct gpio_desc *desc, unsigned long action); +int gpiod_direction_output_nonotify(struct gpio_desc *desc, int value); +int gpiod_direction_input_nonotify(struct gpio_desc *desc); struct gpio_desc_label { struct rcu_head rh;