drm/probe-helper: Add drm_crtc_helper_mode_valid_fixed()

Add drm_crtc_helper_mode_valid_fixed(), which validates a given mode
against a display hardware's mode. Convert simpledrm and use it in a
few other drivers with static modes.

v4:
	* remove empty line after opening brace
v2:
	* rename 'static' and 'hw' to 'fixed' everywhere

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220905141648.22013-3-tzimmermann@suse.de

drivers/gpu/drm/drm_mipi_dbi.c

@@ -309,6 +309,24 @@ err_drm_dev_exit:
 	drm_dev_exit(idx);
 }
 
+/**
+ * mipi_dbi_pipe_mode_valid - MIPI DBI mode-valid helper
+ * @pipe: Simple display pipe
+ * @mode: The mode to test
+ *
+ * This function validates a given display mode against the MIPI DBI's hardware
+ * display. Drivers can use this as their &drm_simple_display_pipe_funcs->mode_valid
+ * callback.
+ */
+enum drm_mode_status mipi_dbi_pipe_mode_valid(struct drm_simple_display_pipe *pipe,
+					      const struct drm_display_mode *mode)
+{
+	struct mipi_dbi_dev *dbidev = drm_to_mipi_dbi_dev(pipe->crtc.dev);
+
+	return drm_crtc_helper_mode_valid_fixed(&pipe->crtc, mode, &dbidev->mode);
+}
+EXPORT_SYMBOL(mipi_dbi_pipe_mode_valid);
+
 /**
  * mipi_dbi_pipe_update - Display pipe update helper
  * @pipe: Simple display pipe

drivers/gpu/drm/drm_probe_helper.c

@@ -1014,6 +1014,30 @@ bool drm_helper_hpd_irq_event(struct drm_device *dev)
 }
 EXPORT_SYMBOL(drm_helper_hpd_irq_event);
 
+/**
+ * drm_crtc_helper_mode_valid_fixed - Validates a display mode
+ * @crtc: the crtc
+ * @mode: the mode to validate
+ * @fixed_mode: the display hardware's mode
+ *
+ * Returns:
+ * MODE_OK on success, or another mode-status code otherwise.
+ */
+enum drm_mode_status drm_crtc_helper_mode_valid_fixed(struct drm_crtc *crtc,
+						      const struct drm_display_mode *mode,
+						      const struct drm_display_mode *fixed_mode)
+{
+	if (mode->hdisplay != fixed_mode->hdisplay && mode->vdisplay != fixed_mode->vdisplay)
+		return MODE_ONE_SIZE;
+	else if (mode->hdisplay != fixed_mode->hdisplay)
+		return MODE_ONE_WIDTH;
+	else if (mode->vdisplay != fixed_mode->vdisplay)
+		return MODE_ONE_HEIGHT;
+
+	return MODE_OK;
+}
+EXPORT_SYMBOL(drm_crtc_helper_mode_valid_fixed);
+
 /**
  * drm_connector_helper_get_modes_from_ddc - Updates the connector's EDID
  *                                           property from the connector's

drivers/gpu/drm/panel/panel-ilitek-ili9341.c

@@ -576,6 +576,7 @@ out_exit:
 }
 
 static const struct drm_simple_display_pipe_funcs ili9341_dbi_funcs = {
+	.mode_valid = mipi_dbi_pipe_mode_valid,
 	.enable = ili9341_dbi_enable,
 	.disable = mipi_dbi_pipe_disable,
 	.update = mipi_dbi_pipe_update,

drivers/gpu/drm/tiny/hx8357d.c

@@ -181,6 +181,7 @@ out_exit:
 }
 
 static const struct drm_simple_display_pipe_funcs hx8357d_pipe_funcs = {
+	.mode_valid = mipi_dbi_pipe_mode_valid,
 	.enable = yx240qv29_enable,
 	.disable = mipi_dbi_pipe_disable,
 	.update = mipi_dbi_pipe_update,

drivers/gpu/drm/tiny/ili9163.c

@@ -100,6 +100,7 @@ out_exit:
 }
 
 static const struct drm_simple_display_pipe_funcs ili9163_pipe_funcs = {
+	.mode_valid = mipi_dbi_pipe_mode_valid,
 	.enable = yx240qv29_enable,
 	.disable = mipi_dbi_pipe_disable,
 	.update = mipi_dbi_pipe_update,

drivers/gpu/drm/tiny/ili9341.c

@@ -137,6 +137,7 @@ out_exit:
 }
 
 static const struct drm_simple_display_pipe_funcs ili9341_pipe_funcs = {
+	.mode_valid = mipi_dbi_pipe_mode_valid,
 	.enable = yx240qv29_enable,
 	.disable = mipi_dbi_pipe_disable,
 	.update = mipi_dbi_pipe_update,

drivers/gpu/drm/tiny/ili9486.c

@@ -150,6 +150,7 @@ static void waveshare_enable(struct drm_simple_display_pipe *pipe,
 }
 
 static const struct drm_simple_display_pipe_funcs waveshare_pipe_funcs = {
+	.mode_valid = mipi_dbi_pipe_mode_valid,
 	.enable = waveshare_enable,
 	.disable = mipi_dbi_pipe_disable,
 	.update = mipi_dbi_pipe_update,

drivers/gpu/drm/tiny/mi0283qt.c

@@ -141,6 +141,7 @@ out_exit:
 }
 
 static const struct drm_simple_display_pipe_funcs mi0283qt_pipe_funcs = {
+	.mode_valid = mipi_dbi_pipe_mode_valid,
 	.enable = mi0283qt_enable,
 	.disable = mipi_dbi_pipe_disable,
 	.update = mipi_dbi_pipe_update,

drivers/gpu/drm/tiny/panel-mipi-dbi.c

@@ -212,6 +212,7 @@ out_exit:
 }
 
 static const struct drm_simple_display_pipe_funcs panel_mipi_dbi_pipe_funcs = {
+	.mode_valid = mipi_dbi_pipe_mode_valid,
 	.enable = panel_mipi_dbi_enable,
 	.disable = mipi_dbi_pipe_disable,
 	.update = mipi_dbi_pipe_update,

drivers/gpu/drm/tiny/repaper.c

@@ -621,6 +621,15 @@ static void power_off(struct repaper_epd *epd)
 	gpiod_set_value_cansleep(epd->discharge, 0);
 }
 
+static enum drm_mode_status repaper_pipe_mode_valid(struct drm_simple_display_pipe *pipe,
+						    const struct drm_display_mode *mode)
+{
+	struct drm_crtc *crtc = &pipe->crtc;
+	struct repaper_epd *epd = drm_to_epd(crtc->dev);
+
+	return drm_crtc_helper_mode_valid_fixed(crtc, mode, epd->mode);
+}
+
 static void repaper_pipe_enable(struct drm_simple_display_pipe *pipe,
 				struct drm_crtc_state *crtc_state,
 				struct drm_plane_state *plane_state)
@@ -831,6 +840,7 @@ static void repaper_pipe_update(struct drm_simple_display_pipe *pipe,
 }
 
 static const struct drm_simple_display_pipe_funcs repaper_pipe_funcs = {
+	.mode_valid = repaper_pipe_mode_valid,
 	.enable = repaper_pipe_enable,
 	.disable = repaper_pipe_disable,
 	.update = repaper_pipe_update,

drivers/gpu/drm/tiny/simpledrm.c

@@ -570,15 +570,7 @@ static enum drm_mode_status simpledrm_crtc_helper_mode_valid(struct drm_crtc *cr
 {
 	struct simpledrm_device *sdev = simpledrm_device_of_dev(crtc->dev);
 
-	if (mode->hdisplay != sdev->mode.hdisplay &&
-	    mode->vdisplay != sdev->mode.vdisplay)
-		return MODE_ONE_SIZE;
-	else if (mode->hdisplay != sdev->mode.hdisplay)
-		return MODE_ONE_WIDTH;
-	else if (mode->vdisplay != sdev->mode.vdisplay)
-		return MODE_ONE_HEIGHT;
-
-	return MODE_OK;
+	return drm_crtc_helper_mode_valid_fixed(crtc, mode, &sdev->mode);
 }
 
 static int simpledrm_crtc_helper_atomic_check(struct drm_crtc *crtc,

drivers/gpu/drm/tiny/st7735r.c

@@ -133,6 +133,7 @@ out_exit:
 }
 
 static const struct drm_simple_display_pipe_funcs st7735r_pipe_funcs = {
+	.mode_valid	= mipi_dbi_pipe_mode_valid,
 	.enable		= st7735r_pipe_enable,
 	.disable	= mipi_dbi_pipe_disable,
 	.update		= mipi_dbi_pipe_update,

include/drm/drm_mipi_dbi.h

@@ -155,6 +155,8 @@ int mipi_dbi_dev_init_with_formats(struct mipi_dbi_dev *dbidev,
 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);
+enum drm_mode_status mipi_dbi_pipe_mode_valid(struct drm_simple_display_pipe *pipe,
+					      const struct drm_display_mode *mode);
 void mipi_dbi_pipe_update(struct drm_simple_display_pipe *pipe,
 			  struct drm_plane_state *old_state);
 void mipi_dbi_enable_flush(struct mipi_dbi_dev *dbidev,

include/drm/drm_probe_helper.h

@@ -3,11 +3,11 @@
 #ifndef __DRM_PROBE_HELPER_H__
 #define __DRM_PROBE_HELPER_H__
 
-#include <linux/types.h>
+#include <drm/drm_modes.h>
 
 struct drm_connector;
+struct drm_crtc;
 struct drm_device;
-struct drm_display_mode;
 struct drm_modeset_acquire_ctx;
 
 int drm_helper_probe_single_connector_modes(struct drm_connector
@@ -27,6 +27,10 @@ void drm_kms_helper_poll_disable(struct drm_device *dev);
 void drm_kms_helper_poll_enable(struct drm_device *dev);
 bool drm_kms_helper_is_poll_worker(void);
 
+enum drm_mode_status drm_crtc_helper_mode_valid_fixed(struct drm_crtc *crtc,
+						      const struct drm_display_mode *mode,
+						      const struct drm_display_mode *fixed_mode);
+
 int drm_connector_helper_get_modes_from_ddc(struct drm_connector *connector);
 int drm_connector_helper_get_modes_fixed(struct drm_connector *connector,
 					 const struct drm_display_mode *fixed_mode);