drm/dsi: Make mipi_dsi_dcs_write() return ssize_t

This function returns the value of the struct mipi_dsi_host_ops'
.transfer() so make sure the return types are consistent.
Acked-by: Andrzej Hajda <a.hajda@samsung.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

drivers/gpu/drm/drm_mipi_dsi.c

@@ -205,7 +205,7 @@ EXPORT_SYMBOL(mipi_dsi_detach);
  * @data: pointer to the command followed by parameters
  * @len: length of @data
  */
-int mipi_dsi_dcs_write(struct mipi_dsi_device *dsi, unsigned int channel,
+ssize_t mipi_dsi_dcs_write(struct mipi_dsi_device *dsi, unsigned int channel,
 			   const void *data, size_t len)
 {
 	const struct mipi_dsi_host_ops *ops = dsi->host->ops;

drivers/gpu/drm/panel/panel-s6e8aa0.c

@@ -133,14 +133,14 @@ static int s6e8aa0_clear_error(struct s6e8aa0 *ctx)
 static void s6e8aa0_dcs_write(struct s6e8aa0 *ctx, const void *data, size_t len)
 {
 	struct mipi_dsi_device *dsi = to_mipi_dsi_device(ctx->dev);
-	int ret;
+	ssize_t ret;
 
 	if (ctx->error < 0)
 		return;
 
 	ret = mipi_dsi_dcs_write(dsi, dsi->channel, data, len);
 	if (ret < 0) {
-		dev_err(ctx->dev, "error %d writing dcs seq: %*ph\n", ret, len,
+		dev_err(ctx->dev, "error %zd writing dcs seq: %*ph\n", ret, len,
 			data);
 		ctx->error = ret;
 	}

include/drm/drm_mipi_dsi.h

@@ -127,7 +127,7 @@ struct mipi_dsi_device {
 
 int mipi_dsi_attach(struct mipi_dsi_device *dsi);
 int mipi_dsi_detach(struct mipi_dsi_device *dsi);
-int mipi_dsi_dcs_write(struct mipi_dsi_device *dsi, unsigned int channel,
+ssize_t mipi_dsi_dcs_write(struct mipi_dsi_device *dsi, unsigned int channel,
 			   const void *data, size_t len);
 ssize_t mipi_dsi_dcs_read(struct mipi_dsi_device *dsi, unsigned int channel,
 			  u8 cmd, void *data, size_t len);