linux-kernel - [PATCH 30/31] staging: wfx: explain the purpose of wfx_send

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Message-Id: <20210910160504.1794332-31-Jerome.Pouiller@silabs.com>
Date:   Fri, 10 Sep 2021 18:05:03 +0200
From:   Jerome Pouiller <Jerome.Pouiller@...abs.com>
To:     devel@...verdev.osuosl.org, linux-wireless@...r.kernel.org
Cc:     netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Kalle Valo <kvalo@...eaurora.org>,
        "David S . Miller" <davem@...emloft.net>,
        Jérôme Pouiller 
        <jerome.pouiller@...abs.com>
Subject: [PATCH 30/31] staging: wfx: explain the purpose of wfx_send_pds()

From: Jérôme Pouiller <jerome.pouiller@...abs.com>

On first look, the goal of wfx_send_pds() is not obvious. A small
explanation is welcomed.

Signed-off-by: Jérôme Pouiller <jerome.pouiller@...abs.com>
---
 drivers/staging/wfx/main.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/drivers/staging/wfx/main.c b/drivers/staging/wfx/main.c
index 83292544b10a..4386e9957ee6 100644
--- a/drivers/staging/wfx/main.c
+++ b/drivers/staging/wfx/main.c
@@ -163,7 +163,20 @@ bool wfx_api_older_than(struct wfx_dev *wdev, int major, int minor)
 	return false;
 }
 
-/* NOTE: wfx_send_pds() destroy buf */
+/* The device needs data about the antenna configuration. This information in
+ * provided by PDS (Platform Data Set, this is the wording used in WF200
+ * documentation) files. For hardware integrators, the full process to create
+ * PDS files is described here:
+ *   https:github.com/SiliconLabs/wfx-firmware/blob/master/PDS/README.md
+ *
+ * So this function aims to send PDS to the device. However, the PDS file is
+ * often bigger than Rx buffers of the chip, so it has to be sent in multiple
+ * parts.
+ *
+ * In add, the PDS data cannot be split anywhere. The PDS files contains tree
+ * structures. Braces are used to enter/leave a level of the tree (in a JSON
+ * fashion). PDS files can only been split between root nodes.
+ */
 int wfx_send_pds(struct wfx_dev *wdev, u8 *buf, size_t len)
 {
 	int ret;
-- 
2.33.0