spi: add devm_spi_optimize_message() helper

This adds a new helper function devm_spi_optimize_message() that
automatically registers spi_unoptimize_message() to be called
when the device is removed.
Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://patch.msgid.link/20240621-devm_spi_optimize_message-v1-2-3f9dcba6e95e@baylibre.comSigned-off-by: Mark Brown <broonie@kernel.org>

Documentation/driver-api/driver-model/devres.rst

@@ -464,6 +464,7 @@ SLAVE DMA ENGINE
 SPI
   devm_spi_alloc_master()
   devm_spi_alloc_slave()
+  devm_spi_optimize_message()
   devm_spi_register_controller()
   devm_spi_register_host()
   devm_spi_register_target()

drivers/spi/spi.c

@@ -4378,6 +4378,33 @@ 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

include/linux/spi/spi.h

@@ -1268,6 +1268,8 @@ static inline void spi_message_free(struct spi_message *m)
 
 extern int spi_optimize_message(struct spi_device *spi, struct spi_message *msg);
 extern void spi_unoptimize_message(struct spi_message *msg);
+extern int devm_spi_optimize_message(struct device *dev, struct spi_device *spi,
+				     struct spi_message *msg);
 
 extern int spi_setup(struct spi_device *spi);
 extern int spi_async(struct spi_device *spi, struct spi_message *message);