From: Thierry Reding treding@nvidia.com
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@nvidia.com --- 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);