From: Mark Brown broonie@linaro.org
Most SPI drivers that implement runtime PM support use identical code to do so: they acquire a runtime PM lock in prepare_transfer_hardware() and then they release it in unprepare_transfer_hardware(). The variations in this are mostly missing error checking and the choice to use autosuspend.
Since these runtime PM calls are normally the only thing in the prepare and unprepare callbacks and the autosuspend API transparently does the right thing on devices with autosuspend disabled factor all of this out into the core with a flag to enable the behaviour.
Signed-off-by: Mark Brown broonie@linaro.org --- drivers/spi/spi.c | 16 ++++++++++++++++ include/linux/spi/spi.h | 4 ++++ 2 files changed, 20 insertions(+)
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 46c3f56..61f71b9 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -553,6 +553,10 @@ static void spi_pump_messages(struct kthread_work *work) master->unprepare_transfer_hardware(master)) dev_err(&master->dev, "failed to unprepare transfer hardware\n"); + if (master->auto_runtime_pm) { + pm_runtime_mark_last_busy(master->dev.parent); + pm_runtime_put_autosuspend(master->dev.parent); + } return; }
@@ -572,11 +576,23 @@ static void spi_pump_messages(struct kthread_work *work) master->busy = true; spin_unlock_irqrestore(&master->queue_lock, flags);
+ if (!was_busy && master->auto_runtime_pm) { + ret = pm_runtime_get_sync(master->dev.parent); + if (ret < 0) { + dev_err(&master->dev, "Failed to power device: %d\n", + ret); + return; + } + } + if (!was_busy && master->prepare_transfer_hardware) { ret = master->prepare_transfer_hardware(master); if (ret) { dev_err(&master->dev, "failed to prepare transfer hardware\n"); + + if (master->auto_runtime_pm) + pm_runtime_put(master->dev.parent); return; } } diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index be40c97..d73059a 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -256,6 +256,8 @@ static inline void spi_unregister_driver(struct spi_driver *sdrv) * @busy: message pump is busy * @running: message pump is running * @rt: whether this queue is set to run as a realtime task + * @auto_runtime_pm: the core should ensure a runtime PM reference is held + * while the hardware is prepared * @prepare_transfer_hardware: a message will soon arrive from the queue * so the subsystem requests the driver to prepare the transfer hardware * by issuing this call @@ -380,11 +382,13 @@ struct spi_master { bool busy; bool running; bool rt; + bool auto_runtime_pm;
int (*prepare_transfer_hardware)(struct spi_master *master); int (*transfer_one_message)(struct spi_master *master, struct spi_message *mesg); int (*unprepare_transfer_hardware)(struct spi_master *master); + /* gpio chip select */ int *cs_gpios; };