Re: [PATCH 2/3] drm/panel: ld9040: Register a backlight device

[Neil Armstrong]

On 03/07/2023 23:47, Paul Cercueil wrote:

Register a backlight device to be able to switch between all the gamma
levels.

Signed-off-by: Paul Cercueil <p...@crapouillou.net>
---
  drivers/gpu/drm/panel/panel-samsung-ld9040.c | 40 ++++++++++++++++++++
  1 file changed, 40 insertions(+)

diff --git a/drivers/gpu/drm/panel/panel-samsung-ld9040.c 
b/drivers/gpu/drm/panel/panel-samsung-ld9040.c
index 7fd9444b42c5..b4f87d6244cb 100644
--- a/drivers/gpu/drm/panel/panel-samsung-ld9040.c
+++ b/drivers/gpu/drm/panel/panel-samsung-ld9040.c
@@ -8,6 +8,7 @@
   * Andrzej Hajda <a.ha...@samsung.com>
  */

+#include <linux/backlight.h>

  #include <linux/delay.h>
  #include <linux/gpio/consumer.h>
  #include <linux/module.h>
@@ -311,8 +312,40 @@ static int ld9040_parse_dt(struct ld9040 *ctx)
        return 0;
  }

+static int ld9040_bl_update_status(struct backlight_device *dev)

+{
+       struct ld9040 *ctx = dev_get_drvdata(&dev->dev);
+
+       ctx->brightness = dev->props.brightness;
+       ld9040_brightness_set(ctx);
+
+       return 0;
+}
+
+static int ld9040_bl_get_intensity(struct backlight_device *dev)
+{
+       if (dev->props.fb_blank == FB_BLANK_UNBLANK &&
+                       dev->props.power == FB_BLANK_UNBLANK)
+               return dev->props.brightness;
+
+       return 0;
+}

You can totally drop the _get_brightness.

Neil

+
+static const struct backlight_ops ld9040_bl_ops = {
+       .get_brightness = ld9040_bl_get_intensity,
+       .update_status  = ld9040_bl_update_status,
+};
+
+static const struct backlight_properties ld9040_bl_props = {
+       .type = BACKLIGHT_RAW,
+       .scale = BACKLIGHT_SCALE_NON_LINEAR,
+       .max_brightness = ARRAY_SIZE(ld9040_gammas) - 1,
+       .brightness = ARRAY_SIZE(ld9040_gammas) - 1,
+};
+
  static int ld9040_probe(struct spi_device *spi)
  {
+       struct backlight_device *bldev;
        struct device *dev = &spi->dev;
        struct ld9040 *ctx;
        int ret;
@@ -354,6 +387,13 @@ static int ld9040_probe(struct spi_device *spi)
        drm_panel_init(&ctx->panel, dev, &ld9040_drm_funcs,
                       DRM_MODE_CONNECTOR_DPI);

+

+       bldev = devm_backlight_device_register(dev, dev_name(dev), dev,
+                                              ctx, &ld9040_bl_ops,
+                                              &ld9040_bl_props);
+       if (IS_ERR(bldev))
+               return PTR_ERR(bldev);
+
        drm_panel_add(&ctx->panel);

return 0;