From: Thierry Reding <treding@xxxxxxxxxx>
Currently the mipi_dsi_dcs_write() function requires the DCS command
byte to be embedded within the write buffer whereas mipi_dsi_dcs_read()
has a separate parameter. Make them more symmetrical by adding an extra
command parameter to mipi_dsi_dcs_write().
The S6E8AA0 driver relies on the old asymmetric API and there's concern
that moving to the new API may be less efficient. Provide a new function
with the old semantics for those cases and make the S6E8AA0 driver use
it instead.
Signed-off-by: Thierry Reding <treding@xxxxxxxxxx>
---
Changes in v4:
- do not handle protocol-level details in mipi_dsi_dcs_write()
Changes in v3:
- reuse mipi_dsi_dcs_write_buffer() in mipi_dsi_dcs_write()
- keep local ops variable for consistency
- use common helper to simplify code
- fix typo in comment
Changes in v2:
- provide mipi_dsi_dcs_write_buffer() for backwards compatibility
drivers/gpu/drm/drm_mipi_dsi.c | 77 +++++++++++++++++++++++++++++------
drivers/gpu/drm/panel/panel-s6e8aa0.c | 2 +-
include/drm/drm_mipi_dsi.h | 6 ++-
3 files changed, 70 insertions(+), 15 deletions(-)
diff --git a/drivers/gpu/drm/drm_mipi_dsi.c b/drivers/gpu/drm/drm_mipi_dsi.c
index 89a228b4eacc..aa1aab24181c 100644
--- a/drivers/gpu/drm/drm_mipi_dsi.c
+++ b/drivers/gpu/drm/drm_mipi_dsi.c
@@ -258,13 +258,19 @@ int mipi_dsi_create_packet(struct mipi_dsi_packet *packet,
EXPORT_SYMBOL(mipi_dsi_create_packet);
/**
- * mipi_dsi_dcs_write - send DCS write command
- * @dsi: DSI device
- * @data: pointer to the command followed by parameters
- * @len: length of @data
+ * mipi_dsi_dcs_write_buffer() - transmit a DCS command with payload
+ * @dsi: DSI peripheral device
+ * @data: buffer containing data to be transmitted
+ * @len: size of transmission buffer
+ *
+ * This function will automatically choose the right data type depending on
+ * the command payload length.
+ *
+ * Return: The number of bytes successfully transmitted or a negative error
+ * code on failure.
*/
-ssize_t mipi_dsi_dcs_write(struct mipi_dsi_device *dsi, const void *data,
- size_t len)
+ssize_t mipi_dsi_dcs_write_buffer(struct mipi_dsi_device *dsi,
+ const void *data, size_t len)
{
struct mipi_dsi_msg msg = {
.channel = dsi->channel,
@@ -275,12 +281,15 @@ ssize_t mipi_dsi_dcs_write(struct mipi_dsi_device *dsi, const void *data,
switch (len) {
case 0:
return -EINVAL;
+
case 1:
msg.type = MIPI_DSI_DCS_SHORT_WRITE;
break;
+
case 2:
msg.type = MIPI_DSI_DCS_SHORT_WRITE_PARAM;
break;
+
default:
msg.type = MIPI_DSI_DCS_LONG_WRITE;
break;
@@ -288,16 +297,60 @@ ssize_t mipi_dsi_dcs_write(struct mipi_dsi_device *dsi, const void *data,
return mipi_dsi_device_transfer(dsi, &msg);
}
+EXPORT_SYMBOL(mipi_dsi_dcs_write_buffer);
+
+/**
+ * mipi_dsi_dcs_write() - send DCS write command
+ * @dsi: DSI peripheral device
+ * @cmd: DCS command
+ * @data: buffer containing the command payload
+ * @len: command payload length
+ *
+ * This function will automatically choose the right data type depending on
+ * the command payload length.
+ *
+ * Return: The number of bytes successfully transmitted or a negative error
+ * code on failure.
+ */
+ssize_t mipi_dsi_dcs_write(struct mipi_dsi_device *dsi, u8 cmd,
+ const void *data, size_t len)
+{
+ ssize_t err;
+ size_t size;
+ u8 *tx;
+
+ if (len > 0) {
+ size = 1 + len;
+
+ tx = kmalloc(size, GFP_KERNEL);
+ if (!tx)
+ return -ENOMEM;
+
+ /* concatenate the DCS command byte and the payload */
+ tx[0] = cmd;
+ memcpy(&tx[1], data, len);
+ } else {
+ tx = &cmd;
+ size = 1;
+ }
+
+ err = mipi_dsi_dcs_write_buffer(dsi, tx, size);
+
+ if (len > 0)
+ kfree(tx);
+
+ return err;
+}
EXPORT_SYMBOL(mipi_dsi_dcs_write);
/**
- * mipi_dsi_dcs_read - send DCS read request command
- * @dsi: DSI device
- * @cmd: DCS read command
- * @data: pointer to read buffer
- * @len: length of @data
+ * mipi_dsi_dcs_read() - send DCS read request command
+ * @dsi: DSI peripheral device
+ * @cmd: DCS command
+ * @data: buffer in which to receive data
+ * @len: size of receive buffer
*
- * Function returns number of read bytes or error code.
+ * Return: The number of bytes read or a negative error code on failure.
*/
ssize_t mipi_dsi_dcs_read(struct mipi_dsi_device *dsi, u8 cmd, void *data,
size_t len)
diff --git a/drivers/gpu/drm/panel/panel-s6e8aa0.c b/drivers/gpu/drm/panel/panel-s6e8aa0.c
index b5217fe37f02..0f85a7c37687 100644
--- a/drivers/gpu/drm/panel/panel-s6e8aa0.c
+++ b/drivers/gpu/drm/panel/panel-s6e8aa0.c
@@ -141,7 +141,7 @@ static void s6e8aa0_dcs_write(struct s6e8aa0 *ctx, const void *data, size_t len)
if (ctx->error < 0)
return;
- ret = mipi_dsi_dcs_write(dsi, data, len);
+ ret = mipi_dsi_dcs_write_buffer(dsi, data, len);
if (ret < 0) {
dev_err(ctx->dev, "error %zd writing dcs seq: %*ph\n", ret, len,
data);
diff --git a/include/drm/drm_mipi_dsi.h b/include/drm/drm_mipi_dsi.h
index 663aa68826f4..e37b1962ab7e 100644
--- a/include/drm/drm_mipi_dsi.h
+++ b/include/drm/drm_mipi_dsi.h
@@ -150,8 +150,10 @@ static inline struct mipi_dsi_device *to_mipi_dsi_device(struct device *dev)
int mipi_dsi_attach(struct mipi_dsi_device *dsi);
int mipi_dsi_detach(struct mipi_dsi_device *dsi);
-ssize_t mipi_dsi_dcs_write(struct mipi_dsi_device *dsi, const void *data,
- size_t len);
+ssize_t mipi_dsi_dcs_write_buffer(struct mipi_dsi_device *dsi,
+ const void *data, size_t len);
+ssize_t mipi_dsi_dcs_write(struct mipi_dsi_device *dsi, u8 cmd,
+ const void *data, size_t len);
ssize_t mipi_dsi_dcs_read(struct mipi_dsi_device *dsi, u8 cmd, void *data,
size_t len);
--
2.1.2
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