From 49834de234f3cf592c3d242c889ca603db8e7050 Mon Sep 17 00:00:00 2001 From: Mark Brown Date: Sun, 28 Jul 2013 14:47:02 +0100 Subject: [PATCH] spi: Provide core support for runtime PM during transfers 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 Reviewed-by: Stephen Warren Acked-by: Linus Walleij --- drivers/spi/spi.c | 16 ++++++++++++++++ include/linux/spi/spi.h | 5 +++++ 2 files changed, 21 insertions(+) diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 978dda2c5239..361cced68069 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 28e440be1c07..bf0204c00053 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -254,6 +254,9 @@ 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, using the parent + * device for the spidev * @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 @@ -374,11 +377,13 @@ 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; };