drm/tinydrm/mipi-dbi: Add mipi_dbi_init_with_formats()

The MIPI DBI standard support more pixel formats than what this helper
supports. Add an init function that lets the driver use different
format(s). This avoids open coding mipi_dbi_init() in st7586.

st7586 sets preferred_depth but this is not necessary since it only
supports one format.

v2: Forgot to remove the mipi->rotation assignment in st7586,
    mipi_dbi_init_with_formats() handles it.

Cc: David Lechner <david@lechnology.com>
Acked-by: David Lechner <david@lechnology.com>
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Tested-by: David Lechner <david@lechnology.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190719155916.62465-11-noralf@tronnes.org

drivers/gpu/drm/tinydrm/mipi-dbi.c

@@ -412,27 +412,34 @@ static const uint32_t mipi_dbi_formats[] = {
 };
 
 /**
- * mipi_dbi_init - MIPI DBI initialization
+ * mipi_dbi_init_with_formats - MIPI DBI initialization with custom formats
  * @mipi: &mipi_dbi structure to initialize
  * @funcs: Display pipe functions
+ * @formats: Array of supported formats (DRM_FORMAT\_\*).
+ * @format_count: Number of elements in @formats
  * @mode: Display mode
  * @rotation: Initial rotation in degrees Counter Clock Wise
+ * @tx_buf_size: Allocate a transmit buffer of this size.
  *
  * This function sets up a &drm_simple_display_pipe with a &drm_connector that
  * has one fixed &drm_display_mode which is rotated according to @rotation.
  * This mode is used to set the mode config min/max width/height properties.
- * Additionally &mipi_dbi.tx_buf is allocated.
  *
- * Supported formats: Native RGB565 and emulated XRGB8888.
+ * Use mipi_dbi_init() if you don't need custom formats.
+ *
+ * Note:
+ * Some of the helper functions expects RGB565 to be the default format and the
+ * transmit buffer sized to fit that.
  *
  * Returns:
  * Zero on success, negative error code on failure.
  */
-int mipi_dbi_init(struct mipi_dbi *mipi,
+int mipi_dbi_init_with_formats(struct mipi_dbi *mipi,
 			       const struct drm_simple_display_pipe_funcs *funcs,
-		  const struct drm_display_mode *mode, unsigned int rotation)
+			       const uint32_t *formats, unsigned int format_count,
+			       const struct drm_display_mode *mode,
+			       unsigned int rotation, size_t tx_buf_size)
 {
-	size_t bufsize = mode->vdisplay * mode->hdisplay * sizeof(u16);
 	struct drm_device *drm = &mipi->drm;
 	int ret;
 
@@ -441,14 +448,13 @@ int mipi_dbi_init(struct mipi_dbi *mipi,
 
 	mutex_init(&mipi->cmdlock);
 
-	mipi->tx_buf = devm_kmalloc(drm->dev, bufsize, GFP_KERNEL);
+	mipi->tx_buf = devm_kmalloc(drm->dev, tx_buf_size, GFP_KERNEL);
 	if (!mipi->tx_buf)
 		return -ENOMEM;
 
 	ret = tinydrm_display_pipe_init(drm, &mipi->pipe, funcs,
 					DRM_MODE_CONNECTOR_SPI,
-					mipi_dbi_formats,
-					ARRAY_SIZE(mipi_dbi_formats), mode,
+					formats, format_count, mode,
 					rotation);
 	if (ret)
 		return ret;
@@ -456,14 +462,43 @@ int mipi_dbi_init(struct mipi_dbi *mipi,
 	drm_plane_enable_fb_damage_clips(&mipi->pipe.plane);
 
 	drm->mode_config.funcs = &mipi_dbi_mode_config_funcs;
-	drm->mode_config.preferred_depth = 16;
 	mipi->rotation = rotation;
 
-	DRM_DEBUG_KMS("preferred_depth=%u, rotation = %u\n",
-		      drm->mode_config.preferred_depth, rotation);
+	DRM_DEBUG_KMS("rotation = %u\n", rotation);
 
 	return 0;
 }
+EXPORT_SYMBOL(mipi_dbi_init_with_formats);
+
+/**
+ * mipi_dbi_init - MIPI DBI initialization
+ * @mipi: &mipi_dbi structure to initialize
+ * @funcs: Display pipe functions
+ * @mode: Display mode
+ * @rotation: Initial rotation in degrees Counter Clock Wise
+ *
+ * This function sets up a &drm_simple_display_pipe with a &drm_connector that
+ * has one fixed &drm_display_mode which is rotated according to @rotation.
+ * This mode is used to set the mode config min/max width/height properties.
+ * Additionally &mipi_dbi.tx_buf is allocated.
+ *
+ * Supported formats: Native RGB565 and emulated XRGB8888.
+ *
+ * Returns:
+ * Zero on success, negative error code on failure.
+ */
+int mipi_dbi_init(struct mipi_dbi *mipi,
+		  const struct drm_simple_display_pipe_funcs *funcs,
+		  const struct drm_display_mode *mode, unsigned int rotation)
+{
+	size_t bufsize = mode->vdisplay * mode->hdisplay * sizeof(u16);
+
+	mipi->drm.mode_config.preferred_depth = 16;
+
+	return mipi_dbi_init_with_formats(mipi, funcs, mipi_dbi_formats,
+					  ARRAY_SIZE(mipi_dbi_formats), mode,
+					  rotation, bufsize);
+}
 EXPORT_SYMBOL(mipi_dbi_init);
 
 /**

drivers/gpu/drm/tinydrm/st7586.c

@@ -24,7 +24,6 @@
 #include <drm/drm_rect.h>
 #include <drm/drm_vblank.h>
 #include <drm/tinydrm/mipi-dbi.h>
-#include <drm/tinydrm/tinydrm-helpers.h>
 
 /* controller-specific commands */
 #define ST7586_DISP_MODE_GRAY	0x38
@@ -283,12 +282,6 @@ static const struct drm_simple_display_pipe_funcs st7586_pipe_funcs = {
 	.prepare_fb	= drm_gem_fb_simple_display_pipe_prepare_fb,
 };
 
-static const struct drm_mode_config_funcs st7586_mode_config_funcs = {
-	.fb_create = drm_gem_fb_create_with_dirty,
-	.atomic_check = drm_atomic_helper_check,
-	.atomic_commit = drm_atomic_helper_commit,
-};
-
 static const struct drm_display_mode st7586_mode = {
 	DRM_SIMPLE_MODE(178, 128, 37, 27),
 };
@@ -342,15 +335,8 @@ static int st7586_probe(struct spi_device *spi)
 	}
 
 	drm_mode_config_init(drm);
-	drm->mode_config.preferred_depth = 32;
-	drm->mode_config.funcs = &st7586_mode_config_funcs;
-
-	mutex_init(&mipi->cmdlock);
 
 	bufsize = (st7586_mode.vdisplay + 2) / 3 * st7586_mode.hdisplay;
-	mipi->tx_buf = devm_kmalloc(dev, bufsize, GFP_KERNEL);
-	if (!mipi->tx_buf)
-		return -ENOMEM;
 
 	mipi->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
 	if (IS_ERR(mipi->reset)) {
@@ -365,7 +351,6 @@ static int st7586_probe(struct spi_device *spi)
 	}
 
 	device_property_read_u32(dev, "rotation", &rotation);
-	mipi->rotation = rotation;
 
 	ret = mipi_dbi_spi_init(spi, mipi, a0);
 	if (ret)
@@ -374,6 +359,12 @@ static int st7586_probe(struct spi_device *spi)
 	/* Cannot read from this controller via SPI */
 	mipi->read_commands = NULL;
 
+	ret = mipi_dbi_init_with_formats(mipi, &st7586_pipe_funcs,
+					 st7586_formats, ARRAY_SIZE(st7586_formats),
+					 &st7586_mode, rotation, bufsize);
+	if (ret)
+		return ret;
+
 	/*
 	 * we are using 8-bit data, so we are not actually swapping anything,
 	 * but setting mipi->swap_bytes makes mipi_dbi_typec3_command() do the
@@ -383,15 +374,6 @@ static int st7586_probe(struct spi_device *spi)
 	 */
 	mipi->swap_bytes = true;
 
-	ret = tinydrm_display_pipe_init(drm, &mipi->pipe, &st7586_pipe_funcs,
-					DRM_MODE_CONNECTOR_SPI,
-					st7586_formats, ARRAY_SIZE(st7586_formats),
-					&st7586_mode, rotation);
-	if (ret)
-		return ret;
-
-	drm_plane_enable_fb_damage_clips(&mipi->pipe.plane);
-
 	drm_mode_config_reset(drm);
 
 	ret = drm_dev_register(drm, 0);
@@ -400,9 +382,6 @@ static int st7586_probe(struct spi_device *spi)
 
 	spi_set_drvdata(spi, drm);
 
-	DRM_DEBUG_KMS("preferred_depth=%u, rotation = %u\n",
-		      drm->mode_config.preferred_depth, rotation);
-
 	drm_fbdev_generic_setup(drm, 0);
 
 	return 0;

include/drm/tinydrm/mipi-dbi.h

@@ -69,6 +69,11 @@ static inline struct mipi_dbi *drm_to_mipi_dbi(struct drm_device *drm)
 
 int mipi_dbi_spi_init(struct spi_device *spi, struct mipi_dbi *mipi,
 		      struct gpio_desc *dc);
+int mipi_dbi_init_with_formats(struct mipi_dbi *mipi,
+			       const struct drm_simple_display_pipe_funcs *funcs,
+			       const uint32_t *formats, unsigned int format_count,
+			       const struct drm_display_mode *mode,
+			       unsigned int rotation, size_t tx_buf_size);
 int mipi_dbi_init(struct mipi_dbi *mipi,
 		  const struct drm_simple_display_pipe_funcs *funcs,
 		  const struct drm_display_mode *mode, unsigned int rotation);