spi: add devm_spi_optimize_message() helper

Merge series from David Lechner <dlechner@baylibre.com>:

In the IIO subsystem, we are finding that it is common to call
spi_optimize_message() during driver probe since the SPI message
doesn't change for the lifetime of the driver. This patch adds a
devm_spi_optimize_message() helper to simplify this common pattern.

1 files changed, 27 insertions, 0 deletions

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 54cbe652a4df..3f953504244b 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -4358,6 +4358,33 @@ static int __spi_async(struct spi_device *spi, struct spi_message *message)
 	return ctlr->transfer(spi, message);
 }
 
+static void devm_spi_unoptimize_message(void *msg)
+{
+	spi_unoptimize_message(msg);
+}
+
+/**
+ * devm_spi_optimize_message - managed version of spi_optimize_message()
+ * @dev: the device that manages @msg (usually @spi->dev)
+ * @spi: the device that will be used for the message
+ * @msg: the message to optimize
+ * Return: zero on success, else a negative error code
+ *
+ * spi_unoptimize_message() will automatically be called when the device is
+ * removed.
+ */
+int devm_spi_optimize_message(struct device *dev, struct spi_device *spi,
+			      struct spi_message *msg)
+{
+	int ret;
+
+	ret = spi_optimize_message(spi, msg);
+	if (ret)
+		return ret;
+
+	return devm_add_action_or_reset(dev, devm_spi_unoptimize_message, msg);
+}
+
 /**
  * spi_async - asynchronous SPI transfer
  * @spi: device with which data will be exchanged