[PATCH v10 15/15] drm/solomon: add SSD130x connector luminance support
From: Mario Limonciello (AMD)
Date: Mon Nov 02 2026 - 14:41:33 EST
From: Mario Limonciello <mario.limonciello@xxxxxxx>
Expose SSD130x contrast through the connector LUMINANCE property when
DRM_LUMINANCE is enabled. Program contrast directly and retain the
backlight class interface when BACKLIGHT_CLASS_DEVICE is enabled.
Reviewed-by: Javier Martinez Canillas <javierm@xxxxxxxxxx>
Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxx>
---
v10:
* Guard the backlight operations and registration with
BACKLIGHT_CLASS_DEVICE
* Fix Kconfig recursive issue
* Add the Reviewed-by tag
---
drivers/gpu/drm/solomon/Kconfig | 2 +-
drivers/gpu/drm/solomon/ssd130x.c | 79 ++++++++++++++++++++++++++++++---------
2 files changed, 62 insertions(+), 19 deletions(-)
diff --git a/drivers/gpu/drm/solomon/Kconfig b/drivers/gpu/drm/solomon/Kconfig
index 400a6cab3a671..76852246eb9c2 100644
--- a/drivers/gpu/drm/solomon/Kconfig
+++ b/drivers/gpu/drm/solomon/Kconfig
@@ -1,7 +1,7 @@
config DRM_SSD130X
tristate "DRM support for Solomon SSD13xx OLED displays"
depends on DRM && MMU
- select BACKLIGHT_CLASS_DEVICE
+ depends on DRM_LUMINANCE || BACKLIGHT_CLASS_DEVICE = y || !BACKLIGHT_CLASS_DEVICE
select DRM_CLIENT_SELECTION
select DRM_GEM_SHMEM_HELPER
select DRM_KMS_HELPER
diff --git a/drivers/gpu/drm/solomon/ssd130x.c b/drivers/gpu/drm/solomon/ssd130x.c
index ee43cf0da8792..aaf2b194273ba 100644
--- a/drivers/gpu/drm/solomon/ssd130x.c
+++ b/drivers/gpu/drm/solomon/ssd130x.c
@@ -1853,7 +1853,8 @@ static void ssd130x_encoder_atomic_enable(struct drm_encoder *encoder,
ssd130x_write_cmd(ssd130x, 1, SSD13XX_DISPLAY_ON);
- backlight_enable(ssd130x->bl_dev);
+ if (ssd130x->bl_dev)
+ backlight_enable(ssd130x->bl_dev);
return;
@@ -1879,7 +1880,8 @@ static void ssd132x_encoder_atomic_enable(struct drm_encoder *encoder,
ssd130x_write_cmd(ssd130x, 1, SSD13XX_DISPLAY_ON);
- backlight_enable(ssd130x->bl_dev);
+ if (ssd130x->bl_dev)
+ backlight_enable(ssd130x->bl_dev);
return;
@@ -1904,7 +1906,8 @@ static void ssd133x_encoder_atomic_enable(struct drm_encoder *encoder,
ssd130x_write_cmd(ssd130x, 1, SSD13XX_DISPLAY_ON);
- backlight_enable(ssd130x->bl_dev);
+ if (ssd130x->bl_dev)
+ backlight_enable(ssd130x->bl_dev);
return;
@@ -1929,7 +1932,8 @@ static void ssd135x_encoder_atomic_enable(struct drm_encoder *encoder,
ssd130x_write_cmd(ssd130x, 1, SSD13XX_DISPLAY_ON);
- backlight_enable(ssd130x->bl_dev);
+ if (ssd130x->bl_dev)
+ backlight_enable(ssd130x->bl_dev);
return;
@@ -1943,7 +1947,8 @@ static void ssd130x_encoder_atomic_disable(struct drm_encoder *encoder,
struct drm_device *drm = encoder->dev;
struct ssd130x_device *ssd130x = drm_to_ssd130x(drm);
- backlight_disable(ssd130x->bl_dev);
+ if (ssd130x->bl_dev)
+ backlight_disable(ssd130x->bl_dev);
ssd130x_write_cmd(ssd130x, 1, SSD13XX_DISPLAY_OFF);
@@ -1980,8 +1985,44 @@ static int ssd130x_connector_get_modes(struct drm_connector *connector)
return drm_connector_helper_get_modes_fixed(connector, &ssd130x->mode);
}
+static int ssd130x_set_luminance_value(struct ssd130x_device *ssd130x,
+ unsigned int luminance)
+{
+ int ret;
+
+ ssd130x->contrast = luminance;
+
+ switch (ssd130x->device_info->family_id) {
+ case SSD133X_FAMILY:
+ return ssd133x_set_contrast(ssd130x, luminance);
+ case SSD135X_FAMILY:
+ return ssd135x_set_contrast(ssd130x, luminance);
+ default:
+ ret = ssd130x_write_cmd(ssd130x, 1, SSD13XX_CONTRAST);
+ if (ret < 0)
+ return ret;
+ return ssd130x_write_cmd(ssd130x, 1, luminance);
+ }
+}
+
+static void ssd130x_connector_set_luminance(const struct drm_connector_state *conn_state)
+{
+ struct ssd130x_device *ssd130x = drm_to_ssd130x(conn_state->connector->dev);
+
+ ssd130x_set_luminance_value(ssd130x, conn_state->luminance);
+}
+
+static void ssd130x_connector_disable_luminance(const struct drm_connector_state *conn_state)
+{
+ struct ssd130x_device *ssd130x = drm_to_ssd130x(conn_state->connector->dev);
+
+ ssd130x_set_luminance_value(ssd130x, 0);
+}
+
static const struct drm_connector_helper_funcs ssd130x_connector_helper_funcs = {
.get_modes = ssd130x_connector_get_modes,
+ .set_luminance = ssd130x_connector_set_luminance,
+ .disable_luminance = ssd130x_connector_disable_luminance,
};
static const struct drm_connector_funcs ssd130x_connector_funcs = {
@@ -2015,23 +2056,13 @@ static const struct drm_driver ssd130x_drm_driver = {
.fops = &ssd130x_fops,
};
+#if IS_ENABLED(CONFIG_BACKLIGHT_CLASS_DEVICE)
static int ssd130x_update_bl(struct backlight_device *bdev)
{
struct ssd130x_device *ssd130x = bl_get_data(bdev);
- int brightness = backlight_get_brightness(bdev);
- int ret;
-
- ssd130x->contrast = brightness;
-
- ret = ssd130x_write_cmd(ssd130x, 1, SSD13XX_CONTRAST);
- if (ret < 0)
- return ret;
- ret = ssd130x_write_cmd(ssd130x, 1, ssd130x->contrast);
- if (ret < 0)
- return ret;
-
- return 0;
+ return ssd130x_set_luminance_value(ssd130x,
+ backlight_get_brightness(bdev));
}
static int ssd133x_update_bl(struct backlight_device *bdev)
@@ -2066,6 +2097,7 @@ static const struct backlight_ops ssd130xfb_bl_ops[] = {
.update_status = ssd135x_update_bl,
},
};
+#endif
static void ssd130x_parse_properties(struct ssd130x_device *ssd130x)
{
@@ -2213,6 +2245,13 @@ static int ssd130x_init_modeset(struct ssd130x_device *ssd130x)
}
drm_connector_helper_add(connector, &ssd130x_connector_helper_funcs);
+ if (IS_ENABLED(CONFIG_DRM_LUMINANCE)) {
+ ret = drm_connector_attach_luminance_property(connector, 0,
+ MAX_CONTRAST,
+ ssd130x->contrast);
+ if (ret)
+ return ret;
+ }
ret = drm_connector_attach_encoder(connector, encoder);
if (ret) {
@@ -2245,7 +2284,9 @@ static int ssd130x_get_resources(struct ssd130x_device *ssd130x)
struct ssd130x_device *ssd130x_probe(struct device *dev, struct regmap *regmap)
{
struct ssd130x_device *ssd130x;
+#if IS_ENABLED(CONFIG_BACKLIGHT_CLASS_DEVICE)
struct backlight_device *bl;
+#endif
struct drm_device *drm;
int ret;
@@ -2270,6 +2311,7 @@ struct ssd130x_device *ssd130x_probe(struct device *dev, struct regmap *regmap)
if (ret)
return ERR_PTR(ret);
+#if IS_ENABLED(CONFIG_BACKLIGHT_CLASS_DEVICE)
bl = devm_backlight_device_register(dev, dev_name(dev), dev, ssd130x,
&ssd130xfb_bl_ops[ssd130x->device_info->family_id],
NULL);
@@ -2280,6 +2322,7 @@ struct ssd130x_device *ssd130x_probe(struct device *dev, struct regmap *regmap)
bl->props.brightness = ssd130x->contrast;
bl->props.max_brightness = MAX_CONTRAST;
ssd130x->bl_dev = bl;
+#endif
ret = ssd130x_init_modeset(ssd130x);
if (ret)
--
2.53.0