mirror of
https://git.openwrt.org/openwrt/openwrt.git
synced 2024-11-22 04:56:15 +00:00
8c405cdccc
The patches were generated from the RPi repo with the following command: git format-patch v6.6.34..rpi-6.1.y Some patches needed rebasing and, as usual, the applied and reverted, wireless drivers, Github workflows, READMEs and defconfigs patches were removed. Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
217 lines
6.9 KiB
Diff
217 lines
6.9 KiB
Diff
From 8b5840b077e3b51ccdf840010600aec211a8990b Mon Sep 17 00:00:00 2001
|
|
From: Sean Young <sean@mess.org>
|
|
Date: Tue, 19 Dec 2023 16:30:27 +0000
|
|
Subject: [PATCH 1128/1135] pwm: Make it possible to apply PWM changes in
|
|
atomic context
|
|
MIME-Version: 1.0
|
|
Content-Type: text/plain; charset=UTF-8
|
|
Content-Transfer-Encoding: 8bit
|
|
|
|
commit 7170d3beafc2373dd76b6b5d6e617d89e4e42b8b upstream.
|
|
|
|
Some PWM devices require sleeping, for example if the pwm device is
|
|
connected over I2C. However, many PWM devices could be used from atomic
|
|
context, e.g. memory mapped PWM. This is useful for, for example, the
|
|
pwm-ir-tx driver which requires precise timing. Sleeping causes havoc
|
|
with the generated IR signal.
|
|
|
|
Since not all PWM devices can support atomic context, we also add a
|
|
pwm_might_sleep() function to check if is not supported.
|
|
|
|
Signed-off-by: Sean Young <sean@mess.org>
|
|
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
|
|
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
|
|
---
|
|
Documentation/driver-api/pwm.rst | 9 +++++
|
|
MAINTAINERS | 2 +-
|
|
drivers/pwm/core.c | 62 ++++++++++++++++++++++++++------
|
|
include/linux/pwm.h | 25 +++++++++++++
|
|
4 files changed, 86 insertions(+), 12 deletions(-)
|
|
|
|
--- a/Documentation/driver-api/pwm.rst
|
|
+++ b/Documentation/driver-api/pwm.rst
|
|
@@ -46,6 +46,15 @@ After being requested, a PWM has to be c
|
|
This API controls both the PWM period/duty_cycle config and the
|
|
enable/disable state.
|
|
|
|
+PWM devices can be used from atomic context, if the PWM does not sleep. You
|
|
+can check if this the case with::
|
|
+
|
|
+ bool pwm_might_sleep(struct pwm_device *pwm);
|
|
+
|
|
+If false, the PWM can also be configured from atomic context with::
|
|
+
|
|
+ int pwm_apply_atomic(struct pwm_device *pwm, struct pwm_state *state);
|
|
+
|
|
As a consumer, don't rely on the output's state for a disabled PWM. If it's
|
|
easily possible, drivers are supposed to emit the inactive state, but some
|
|
drivers cannot. If you rely on getting the inactive state, use .duty_cycle=0,
|
|
--- a/MAINTAINERS
|
|
+++ b/MAINTAINERS
|
|
@@ -17437,7 +17437,7 @@ F: drivers/video/backlight/pwm_bl.c
|
|
F: include/dt-bindings/pwm/
|
|
F: include/linux/pwm.h
|
|
F: include/linux/pwm_backlight.h
|
|
-K: pwm_(config|apply_might_sleep|ops)
|
|
+K: pwm_(config|apply_might_sleep|apply_atomic|ops)
|
|
|
|
PXA GPIO DRIVER
|
|
M: Robert Jarzmik <robert.jarzmik@free.fr>
|
|
--- a/drivers/pwm/core.c
|
|
+++ b/drivers/pwm/core.c
|
|
@@ -489,24 +489,15 @@ static void pwm_apply_debug(struct pwm_d
|
|
}
|
|
|
|
/**
|
|
- * pwm_apply_might_sleep() - atomically apply a new state to a PWM device
|
|
+ * __pwm_apply() - atomically apply a new state to a PWM device
|
|
* @pwm: PWM device
|
|
* @state: new state to apply
|
|
*/
|
|
-int pwm_apply_might_sleep(struct pwm_device *pwm, const struct pwm_state *state)
|
|
+static int __pwm_apply(struct pwm_device *pwm, const struct pwm_state *state)
|
|
{
|
|
struct pwm_chip *chip;
|
|
int err;
|
|
|
|
- /*
|
|
- * Some lowlevel driver's implementations of .apply() make use of
|
|
- * mutexes, also with some drivers only returning when the new
|
|
- * configuration is active calling pwm_apply_might_sleep() from atomic context
|
|
- * is a bad idea. So make it explicit that calling this function might
|
|
- * sleep.
|
|
- */
|
|
- might_sleep();
|
|
-
|
|
if (!pwm || !state || !state->period ||
|
|
state->duty_cycle > state->period)
|
|
return -EINVAL;
|
|
@@ -535,9 +526,58 @@ int pwm_apply_might_sleep(struct pwm_dev
|
|
|
|
return 0;
|
|
}
|
|
+
|
|
+/**
|
|
+ * pwm_apply_might_sleep() - atomically apply a new state to a PWM device
|
|
+ * Cannot be used in atomic context.
|
|
+ * @pwm: PWM device
|
|
+ * @state: new state to apply
|
|
+ */
|
|
+int pwm_apply_might_sleep(struct pwm_device *pwm, const struct pwm_state *state)
|
|
+{
|
|
+ int err;
|
|
+
|
|
+ /*
|
|
+ * Some lowlevel driver's implementations of .apply() make use of
|
|
+ * mutexes, also with some drivers only returning when the new
|
|
+ * configuration is active calling pwm_apply_might_sleep() from atomic context
|
|
+ * is a bad idea. So make it explicit that calling this function might
|
|
+ * sleep.
|
|
+ */
|
|
+ might_sleep();
|
|
+
|
|
+ if (IS_ENABLED(CONFIG_PWM_DEBUG) && pwm->chip->atomic) {
|
|
+ /*
|
|
+ * Catch any drivers that have been marked as atomic but
|
|
+ * that will sleep anyway.
|
|
+ */
|
|
+ non_block_start();
|
|
+ err = __pwm_apply(pwm, state);
|
|
+ non_block_end();
|
|
+ } else {
|
|
+ err = __pwm_apply(pwm, state);
|
|
+ }
|
|
+
|
|
+ return err;
|
|
+}
|
|
EXPORT_SYMBOL_GPL(pwm_apply_might_sleep);
|
|
|
|
/**
|
|
+ * pwm_apply_atomic() - apply a new state to a PWM device from atomic context
|
|
+ * Not all PWM devices support this function, check with pwm_might_sleep().
|
|
+ * @pwm: PWM device
|
|
+ * @state: new state to apply
|
|
+ */
|
|
+int pwm_apply_atomic(struct pwm_device *pwm, const struct pwm_state *state)
|
|
+{
|
|
+ WARN_ONCE(!pwm->chip->atomic,
|
|
+ "sleeping PWM driver used in atomic context\n");
|
|
+
|
|
+ return __pwm_apply(pwm, state);
|
|
+}
|
|
+EXPORT_SYMBOL_GPL(pwm_apply_atomic);
|
|
+
|
|
+/**
|
|
* pwm_capture() - capture and report a PWM signal
|
|
* @pwm: PWM device
|
|
* @result: structure to fill with capture result
|
|
--- a/include/linux/pwm.h
|
|
+++ b/include/linux/pwm.h
|
|
@@ -289,6 +289,7 @@ struct pwm_ops {
|
|
* @npwm: number of PWMs controlled by this chip
|
|
* @of_xlate: request a PWM device given a device tree PWM specifier
|
|
* @of_pwm_n_cells: number of cells expected in the device tree PWM specifier
|
|
+ * @atomic: can the driver's ->apply() be called in atomic context
|
|
* @list: list node for internal use
|
|
* @pwms: array of PWM devices allocated by the framework
|
|
*/
|
|
@@ -301,6 +302,7 @@ struct pwm_chip {
|
|
struct pwm_device * (*of_xlate)(struct pwm_chip *chip,
|
|
const struct of_phandle_args *args);
|
|
unsigned int of_pwm_n_cells;
|
|
+ bool atomic;
|
|
|
|
/* only used internally by the PWM framework */
|
|
struct list_head list;
|
|
@@ -310,6 +312,7 @@ struct pwm_chip {
|
|
#if IS_ENABLED(CONFIG_PWM)
|
|
/* PWM user APIs */
|
|
int pwm_apply_might_sleep(struct pwm_device *pwm, const struct pwm_state *state);
|
|
+int pwm_apply_atomic(struct pwm_device *pwm, const struct pwm_state *state);
|
|
int pwm_adjust_config(struct pwm_device *pwm);
|
|
|
|
/**
|
|
@@ -380,6 +383,17 @@ static inline void pwm_disable(struct pw
|
|
pwm_apply_might_sleep(pwm, &state);
|
|
}
|
|
|
|
+/**
|
|
+ * pwm_might_sleep() - is pwm_apply_atomic() supported?
|
|
+ * @pwm: PWM device
|
|
+ *
|
|
+ * Returns: false if pwm_apply_atomic() can be called from atomic context.
|
|
+ */
|
|
+static inline bool pwm_might_sleep(struct pwm_device *pwm)
|
|
+{
|
|
+ return !pwm->chip->atomic;
|
|
+}
|
|
+
|
|
/* PWM provider APIs */
|
|
int pwm_capture(struct pwm_device *pwm, struct pwm_capture *result,
|
|
unsigned long timeout);
|
|
@@ -408,6 +422,11 @@ struct pwm_device *devm_fwnode_pwm_get(s
|
|
struct fwnode_handle *fwnode,
|
|
const char *con_id);
|
|
#else
|
|
+static inline bool pwm_might_sleep(struct pwm_device *pwm)
|
|
+{
|
|
+ return true;
|
|
+}
|
|
+
|
|
static inline int pwm_apply_might_sleep(struct pwm_device *pwm,
|
|
const struct pwm_state *state)
|
|
{
|
|
@@ -415,6 +434,12 @@ static inline int pwm_apply_might_sleep(
|
|
return -EOPNOTSUPP;
|
|
}
|
|
|
|
+static inline int pwm_apply_atomic(struct pwm_device *pwm,
|
|
+ const struct pwm_state *state)
|
|
+{
|
|
+ return -EOPNOTSUPP;
|
|
+}
|
|
+
|
|
static inline int pwm_adjust_config(struct pwm_device *pwm)
|
|
{
|
|
return -EOPNOTSUPP;
|