[PATCH v3 4/4] drm/stm: add an option to change FB bpp
From: Dario Binacchi
Date: Fri Jun 09 2023 - 02:21:27 EST
Boards that use the STM32F{4,7} series have limited amounts of RAM. The
added parameter allows users to size, within certain limits, the memory
footprint required by the framebuffer.
Signed-off-by: Dario Binacchi <dario.binacchi@xxxxxxxxxxxxxxxxxxxx>
---
Changes in v3:
- drop [4/6] dt-bindings: display: simple: add Rocktech RK043FN48H
Applied to https://anongit.freedesktop.org/git/drm/drm-misc.git (drm-misc-next):
https://cgit.freedesktop.org/drm/drm-misc/commit/?id=c42a37a27c777d63961dd634a30f7c887949491a
- drop [5/6] drm/panel: simple: add support for Rocktech RK043FN48H panel
Applied to https://anongit.freedesktop.org/git/drm/drm-misc.git (drm-misc-next)
https://cgit.freedesktop.org/drm/drm-misc/commit/?id=13cdd12a9f934158f4ec817cf048fcb4384aa9dc
drivers/gpu/drm/stm/drv.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/stm/drv.c b/drivers/gpu/drm/stm/drv.c
index 422220df7d8c..65be2b442a6a 100644
--- a/drivers/gpu/drm/stm/drv.c
+++ b/drivers/gpu/drm/stm/drv.c
@@ -30,6 +30,11 @@
#define STM_MAX_FB_WIDTH 2048
#define STM_MAX_FB_HEIGHT 2048 /* same as width to handle orientation */
+static uint stm_bpp = 16;
+
+MODULE_PARM_DESC(bpp, "bits-per-pixel (default: 16)");
+module_param_named(bpp, stm_bpp, uint, 0644);
+
static const struct drm_mode_config_funcs drv_mode_config_funcs = {
.fb_create = drm_gem_fb_create,
.atomic_check = drm_atomic_helper_check,
@@ -93,6 +98,7 @@ static int drv_load(struct drm_device *ddev)
ddev->mode_config.min_height = 0;
ddev->mode_config.max_width = STM_MAX_FB_WIDTH;
ddev->mode_config.max_height = STM_MAX_FB_HEIGHT;
+ ddev->mode_config.preferred_depth = stm_bpp;
ddev->mode_config.funcs = &drv_mode_config_funcs;
ddev->mode_config.normalize_zpos = true;
@@ -203,7 +209,7 @@ static int stm_drm_platform_probe(struct platform_device *pdev)
if (ret)
goto err_put;
- drm_fbdev_dma_setup(ddev, 16);
+ drm_fbdev_dma_setup(ddev, stm_bpp);
return 0;
--
2.32.0