diff options
Diffstat (limited to 'drivers/mux/core.c')
| -rw-r--r-- | drivers/mux/core.c | 38 |
1 files changed, 32 insertions, 6 deletions
diff --git a/drivers/mux/core.c b/drivers/mux/core.c index 1fb22388e7e0..22f4709768d1 100644 --- a/drivers/mux/core.c +++ b/drivers/mux/core.c @@ -9,6 +9,7 @@ #define pr_fmt(fmt) "mux-core: " fmt +#include <linux/delay.h> #include <linux/device.h> #include <linux/err.h> #include <linux/export.h> @@ -116,6 +117,7 @@ struct mux_chip *mux_chip_alloc(struct device *dev, sema_init(&mux->lock, 1); mux->cached_state = MUX_CACHE_UNKNOWN; mux->idle_state = MUX_IDLE_AS_IS; + mux->last_change = ktime_get(); } device_initialize(&mux_chip->dev); @@ -129,6 +131,8 @@ static int mux_control_set(struct mux_control *mux, int state) int ret = mux->chip->ops->set(mux, state); mux->cached_state = ret < 0 ? MUX_CACHE_UNKNOWN : state; + if (ret >= 0) + mux->last_change = ktime_get(); return ret; } @@ -314,10 +318,25 @@ static int __mux_control_select(struct mux_control *mux, int state) return ret; } +static void mux_control_delay(struct mux_control *mux, unsigned int delay_us) +{ + ktime_t delayend; + s64 remaining; + + if (!delay_us) + return; + + delayend = ktime_add_us(mux->last_change, delay_us); + remaining = ktime_us_delta(delayend, ktime_get()); + if (remaining > 0) + fsleep(remaining); +} + /** - * mux_control_select() - Select the given multiplexer state. + * mux_control_select_delay() - Select the given multiplexer state. * @mux: The mux-control to request a change of state from. * @state: The new requested state. + * @delay_us: The time to delay (in microseconds) if the mux state is changed. * * On successfully selecting the mux-control state, it will be locked until * there is a call to mux_control_deselect(). If the mux-control is already @@ -331,7 +350,8 @@ static int __mux_control_select(struct mux_control *mux, int state) * Return: 0 when the mux-control state has the requested state or a negative * errno on error. */ -int mux_control_select(struct mux_control *mux, unsigned int state) +int mux_control_select_delay(struct mux_control *mux, unsigned int state, + unsigned int delay_us) { int ret; @@ -340,18 +360,21 @@ int mux_control_select(struct mux_control *mux, unsigned int state) return ret; ret = __mux_control_select(mux, state); + if (ret >= 0) + mux_control_delay(mux, delay_us); if (ret < 0) up(&mux->lock); return ret; } -EXPORT_SYMBOL_GPL(mux_control_select); +EXPORT_SYMBOL_GPL(mux_control_select_delay); /** - * mux_control_try_select() - Try to select the given multiplexer state. + * mux_control_try_select_delay() - Try to select the given multiplexer state. * @mux: The mux-control to request a change of state from. * @state: The new requested state. + * @delay_us: The time to delay (in microseconds) if the mux state is changed. * * On successfully selecting the mux-control state, it will be locked until * mux_control_deselect() called. @@ -363,7 +386,8 @@ EXPORT_SYMBOL_GPL(mux_control_select); * Return: 0 when the mux-control state has the requested state or a negative * errno on error. Specifically -EBUSY if the mux-control is contended. */ -int mux_control_try_select(struct mux_control *mux, unsigned int state) +int mux_control_try_select_delay(struct mux_control *mux, unsigned int state, + unsigned int delay_us) { int ret; @@ -371,13 +395,15 @@ int mux_control_try_select(struct mux_control *mux, unsigned int state) return -EBUSY; ret = __mux_control_select(mux, state); + if (ret >= 0) + mux_control_delay(mux, delay_us); if (ret < 0) up(&mux->lock); return ret; } -EXPORT_SYMBOL_GPL(mux_control_try_select); +EXPORT_SYMBOL_GPL(mux_control_try_select_delay); /** * mux_control_deselect() - Deselect the previously selected multiplexer state. |