[PATCH v8 9/9] bus: mhi: Improve documentation on channel transfer setup APIs

[Bhaumik Bhatt <bbhatt@codeaurora.org>]

The mhi_prepare_for_transfer() and mhi_unprepare_from_transfer()
APIs could use better explanation. Add details on what MHI does
when these APIs are used.

Signed-off-by: Bhaumik Bhatt <bbhatt@codeaurora.org>
Reviewed-by: Hemant Kumar <hemantk@codeaurora.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
---
 include/linux/mhi.h | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/include/linux/mhi.h b/include/linux/mhi.h
index b16afd3..43a66e1 100644
--- a/include/linux/mhi.h
+++ b/include/linux/mhi.h
@@ -714,13 +714,27 @@ int mhi_device_get_sync(struct mhi_device *mhi_dev);
 void mhi_device_put(struct mhi_device *mhi_dev);
 
 /**
- * mhi_prepare_for_transfer - Setup channel for data transfer
+ * mhi_prepare_for_transfer - Setup UL and DL channels for data transfer.
+ *                            Allocate and initialize the channel context and
+ *                            also issue the START channel command to both
+ *                            channels. Channels can be started only if both
+ *                            host and device execution environments match and
+ *                            channels are in a DISABLED state.
  * @mhi_dev: Device associated with the channels
  */
 int mhi_prepare_for_transfer(struct mhi_device *mhi_dev);
 
 /**
- * mhi_unprepare_from_transfer - Unprepare the channels
+ * mhi_unprepare_from_transfer - Reset UL and DL channels for data transfer.
+ *                               Issue the RESET channel command and let the
+ *                               device clean-up the context so no incoming
+ *                               transfers are seen on the host. Free memory
+ *                               associated with the context on host. If device
+ *                               is unresponsive, only perform a host side
+ *                               clean-up. Channels can be reset only if both
+ *                               host and device execution environments match
+ *                               and channels are in an ENABLED, STOPPED or
+ *                               SUSPENDED state.
  * @mhi_dev: Device associated with the channels
  */
 void mhi_unprepare_from_transfer(struct mhi_device *mhi_dev);
-- 
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