linux-kernel - [PATCH 2/4] drm/mipi-dsi: remove deprecated write

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Message-ID: <20250921183720.237761-4-rtapadia730@gmail.com>
Date: Mon, 22 Sep 2025 00:07:20 +0530
From: rtapadia730@...il.com
To: neil.armstrong@...aro.org,
	maarten.lankhorst@...ux.intel.com
Cc: mripard@...nel.org,
	tzimmermann@...e.de,
	airlied@...il.com,
	simona@...ll.ch,
	jessica.zhang@....qualcomm.com,
	dri-devel@...ts.freedesktop.org,
	linux-kernel@...r.kernel.org,
	linux-doc@...r.kernel.org,
	corbet@....net,
	Rajeev Tapadia <rtapadia730@...il.com>
Subject: [PATCH 2/4] drm/mipi-dsi: remove deprecated write_seq macro and chatty helper

From: Rajeev Tapadia <rtapadia730@...il.com>

The mipi_dsi_generic_write_seq() macro is non-intuitive because it
returns out of the caller on error, leading to subtle bugs in panel
drivers. Similarly, mipi_dsi_generic_write_chatty() is redundant.

Both are removed in favour of mipi_dsi_generic_write_multi(), which
provides proper error accumulation for multiple DSI writes and is safer
for panel drivers.

Signed-off-by: Rajeev Tapadia <rtapadia730@...il.com>
---
 drivers/gpu/drm/drm_mipi_dsi.c | 32 +++-----------------------------
 include/drm/drm_mipi_dsi.h     | 23 -----------------------
 2 files changed, 3 insertions(+), 52 deletions(-)

diff --git a/drivers/gpu/drm/drm_mipi_dsi.c b/drivers/gpu/drm/drm_mipi_dsi.c
index 3a9b3278a6e3..bc847ab5c822 100644
--- a/drivers/gpu/drm/drm_mipi_dsi.c
+++ b/drivers/gpu/drm/drm_mipi_dsi.c
@@ -773,42 +773,16 @@ ssize_t mipi_dsi_generic_write(struct mipi_dsi_device *dsi, const void *payload,
 EXPORT_SYMBOL(mipi_dsi_generic_write);
 
 /**
- * mipi_dsi_generic_write_chatty() - mipi_dsi_generic_write() w/ an error log
- * @dsi: DSI peripheral device
+ * mipi_dsi_generic_write_multi()
+ * @ctx: Context for multiple DSI transactions
  * @payload: buffer containing the payload
  * @size: size of payload buffer
  *
  * Like mipi_dsi_generic_write() but includes a dev_err()
- * call for you and returns 0 upon success, not the number of bytes sent.
+ * call for you.
  *
  * Return: 0 on success or a negative error code on failure.
  */
-int mipi_dsi_generic_write_chatty(struct mipi_dsi_device *dsi,
-				  const void *payload, size_t size)
-{
-	struct device *dev = &dsi->dev;
-	ssize_t ret;
-
-	ret = mipi_dsi_generic_write(dsi, payload, size);
-	if (ret < 0) {
-		dev_err(dev, "sending generic data %*ph failed: %zd\n",
-			(int)size, payload, ret);
-		return ret;
-	}
-
-	return 0;
-}
-EXPORT_SYMBOL(mipi_dsi_generic_write_chatty);
-
-/**
- * mipi_dsi_generic_write_multi() - mipi_dsi_generic_write_chatty() w/ accum_err
- * @ctx: Context for multiple DSI transactions
- * @payload: buffer containing the payload
- * @size: size of payload buffer
- *
- * Like mipi_dsi_generic_write_chatty() but deals with errors in a way that
- * makes it convenient to make several calls in a row.
- */
 void mipi_dsi_generic_write_multi(struct mipi_dsi_multi_context *ctx,
 				  const void *payload, size_t size)
 {
diff --git a/include/drm/drm_mipi_dsi.h b/include/drm/drm_mipi_dsi.h
index 57a869a6f6e8..e4d26ed7a62a 100644
--- a/include/drm/drm_mipi_dsi.h
+++ b/include/drm/drm_mipi_dsi.h
@@ -288,8 +288,6 @@ void mipi_dsi_picture_parameter_set_multi(struct mipi_dsi_multi_context *ctx,
 
 ssize_t mipi_dsi_generic_write(struct mipi_dsi_device *dsi, const void *payload,
 			       size_t size);
-int mipi_dsi_generic_write_chatty(struct mipi_dsi_device *dsi,
-				  const void *payload, size_t size);
 void mipi_dsi_generic_write_multi(struct mipi_dsi_multi_context *ctx,
 				  const void *payload, size_t size);
 ssize_t mipi_dsi_generic_read(struct mipi_dsi_device *dsi, const void *params,
@@ -382,27 +380,6 @@ void mipi_dsi_dcs_set_tear_scanline_multi(struct mipi_dsi_multi_context *ctx,
 					  u16 scanline);
 void mipi_dsi_dcs_set_tear_off_multi(struct mipi_dsi_multi_context *ctx);
 
-/**
- * mipi_dsi_generic_write_seq - transmit data using a generic write packet
- *
- * This macro will print errors for you and will RETURN FROM THE CALLING
- * FUNCTION (yes this is non-intuitive) upon error.
- *
- * Because of the non-intuitive return behavior, THIS MACRO IS DEPRECATED.
- * Please replace calls of it with mipi_dsi_generic_write_seq_multi().
- *
- * @dsi: DSI peripheral device
- * @seq: buffer containing the payload
- */
-#define mipi_dsi_generic_write_seq(dsi, seq...)                                \
-	do {                                                                   \
-		static const u8 d[] = { seq };                                 \
-		int ret;                                                       \
-		ret = mipi_dsi_generic_write_chatty(dsi, d, ARRAY_SIZE(d));    \
-		if (ret < 0)                                                   \
-			return ret;                                            \
-	} while (0)
-
 /**
  * mipi_dsi_generic_write_seq_multi - transmit data using a generic write packet
  *
-- 
2.51.0


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