drm/mipi-dbi: Support custom pipelines with drm_mipi_dbi_dev_init()

Initialize the mipi-dbi device with drm_mipi_dbi_dev_init() without
creating a modesetting pipeline. Will allow for mipi-dbi drivers
without simple-display helpers.

As the new helper is a DRM function, add the drm_ prefix. Mipi-dbi
interfaces currently lack this.

v3:
- document tx_buf_size parameter (David)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: David Lechner <david@lechnology.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Link: https://patch.msgid.link/20260319160110.109610-3-tzimmermann@suse.de

diff --git a/drivers/gpu/drm/drm_mipi_dbi.c b/drivers/gpu/drm/drm_mipi_dbi.c
index bb6cebc583be702bb51097a0c65f7eba6bff4efe..bc5444ca7ac6a1a81902bbe8207b253a7eac16ee 100644 (file)
--- a/drivers/gpu/drm/drm_mipi_dbi.c
+++ b/drivers/gpu/drm/drm_mipi_dbi.c
@@ -554,6 +554,59 @@ static const uint32_t mipi_dbi_formats[] = {
        DRM_FORMAT_XRGB8888,
 };
 
+/**
+ * drm_mipi_dbi_dev_init - MIPI DBI device initialization
+ * @dbidev: MIPI DBI device structure to initialize
+ * @mode: Hardware display mode
+ * @format: Hardware color format (DRM_FORMAT\_\*).
+ * @rotation: Initial rotation in degrees Counter Clock Wise
+ * @tx_buf_size: Allocate a transmit buffer of at least this size.
+ *
+ * Initializes a MIPI-DBI device. The minimum size of the transmit buffer
+ * in @tx_buf_size is optional. Pass 0 to allocate enough memory to transmit
+ * a single scanline of the display.
+ *
+ * Returns:
+ * Zero on success, negative error code on failure.
+ */
+int drm_mipi_dbi_dev_init(struct mipi_dbi_dev *dbidev, const struct drm_display_mode *mode,
+                         u32 format, unsigned int rotation, size_t tx_buf_size)
+{
+       struct drm_device *drm = &dbidev->drm;
+       int ret;
+
+       if (!dbidev->dbi.command)
+               return -EINVAL;
+
+       if (!tx_buf_size) {
+               const struct drm_format_info *info = drm_format_info(format);
+
+               tx_buf_size = drm_format_info_min_pitch(info, 0, mode->hdisplay) *
+                             mode->vdisplay;
+       }
+
+       dbidev->tx_buf = devm_kmalloc(drm->dev, tx_buf_size, GFP_KERNEL);
+       if (!dbidev->tx_buf)
+               return -ENOMEM;
+
+       drm_mode_copy(&dbidev->mode, mode);
+       ret = mipi_dbi_rotate_mode(&dbidev->mode, rotation);
+       if (ret) {
+               drm_err(drm, "Illegal rotation value %u\n", rotation);
+               return -EINVAL;
+       }
+
+       dbidev->rotation = rotation;
+       drm_dbg(drm, "rotation = %u\n", rotation);
+
+       dbidev->pixel_format = format;
+       if (dbidev->pixel_format == DRM_FORMAT_RGB888)
+               dbidev->dbi.write_memory_bpw = 8;
+
+       return 0;
+}
+EXPORT_SYMBOL(drm_mipi_dbi_dev_init);
+
 /**
  * mipi_dbi_dev_init_with_formats - MIPI DBI device initialization with custom formats
  * @dbidev: MIPI DBI device structure to initialize
@@ -590,24 +643,14 @@ int mipi_dbi_dev_init_with_formats(struct mipi_dbi_dev *dbidev,
        struct drm_device *drm = &dbidev->drm;
        int ret;
 
-       if (!dbidev->dbi.command)
-               return -EINVAL;
+       ret = drm_mipi_dbi_dev_init(dbidev, mode, formats[0], rotation, tx_buf_size);
+       if (ret)
+               return ret;
 
        ret = drmm_mode_config_init(drm);
        if (ret)
                return ret;
 
-       dbidev->tx_buf = devm_kmalloc(drm->dev, tx_buf_size, GFP_KERNEL);
-       if (!dbidev->tx_buf)
-               return -ENOMEM;
-
-       drm_mode_copy(&dbidev->mode, mode);
-       ret = mipi_dbi_rotate_mode(&dbidev->mode, rotation);
-       if (ret) {
-               DRM_ERROR("Illegal rotation value %u\n", rotation);
-               return -EINVAL;
-       }
-
        drm_connector_helper_add(&dbidev->connector, &mipi_dbi_connector_hfuncs);
        ret = drm_connector_init(drm, &dbidev->connector, &mipi_dbi_connector_funcs,
                                 DRM_MODE_CONNECTOR_SPI);
@@ -628,13 +671,6 @@ int mipi_dbi_dev_init_with_formats(struct mipi_dbi_dev *dbidev,
        drm->mode_config.max_height = dbidev->mode.vdisplay;
        drm->mode_config.helper_private = &mipi_dbi_mode_config_helper_funcs;
 
-       dbidev->rotation = rotation;
-       dbidev->pixel_format = formats[0];
-       if (formats[0] == DRM_FORMAT_RGB888)
-               dbidev->dbi.write_memory_bpw = 8;
-
-       DRM_DEBUG_KMS("rotation = %u\n", rotation);
-
        return 0;
 }
 EXPORT_SYMBOL(mipi_dbi_dev_init_with_formats);
@@ -660,13 +696,11 @@ int mipi_dbi_dev_init(struct mipi_dbi_dev *dbidev,
                      const struct drm_simple_display_pipe_funcs *funcs,
                      const struct drm_display_mode *mode, unsigned int rotation)
 {
-       size_t bufsize = (u32)mode->vdisplay * mode->hdisplay * sizeof(u16);
-
        dbidev->drm.mode_config.preferred_depth = 16;
 
        return mipi_dbi_dev_init_with_formats(dbidev, funcs, mipi_dbi_formats,
                                              ARRAY_SIZE(mipi_dbi_formats), mode,
-                                             rotation, bufsize);
+                                             rotation, 0);
 }
 EXPORT_SYMBOL(mipi_dbi_dev_init);
 

diff --git a/include/drm/drm_mipi_dbi.h b/include/drm/drm_mipi_dbi.h
index 637be84d3d5ae1ed529242d82c1a4e131bed87eb..9c0e015dd92991efc3ab25ab2d892b5b888d7cdc 100644 (file)
--- a/include/drm/drm_mipi_dbi.h
+++ b/include/drm/drm_mipi_dbi.h
@@ -164,6 +164,10 @@ static inline struct mipi_dbi_dev *drm_to_mipi_dbi_dev(struct drm_device *drm)
 
 int mipi_dbi_spi_init(struct spi_device *spi, struct mipi_dbi *dbi,
                      struct gpio_desc *dc);
+
+int drm_mipi_dbi_dev_init(struct mipi_dbi_dev *dbidev, const struct drm_display_mode *mode,
+                         u32 format, unsigned int rotation, size_t tx_buf_size);
+
 int mipi_dbi_dev_init_with_formats(struct mipi_dbi_dev *dbidev,
                                   const struct drm_simple_display_pipe_funcs *funcs,
                                   const uint32_t *formats, unsigned int format_count,