This is a note to let you know that I've just added the patch titled
drm/mipi-dsi: Fix byte order of 16-bit DCS set/get brightness
to the 4.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
drm-mipi-dsi-fix-byte-order-of-16-bit-dcs-set-get-br.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 51259aacb3e58a89dd84c99bb5a2fffa21eff74b
Author: Daniel Mentz <danielmentz@xxxxxxxxxx>
Date: Mon Jan 16 17:49:07 2023 -0500
drm/mipi-dsi: Fix byte order of 16-bit DCS set/get brightness
[ Upstream commit c9d27c6be518b4ef2966d9564654ef99292ea1b3 ]
The MIPI DCS specification demands that brightness values are sent in
big endian byte order. It also states that one parameter (i.e. one byte)
shall be sent/received for 8 bit wide values, and two parameters shall
be used for values that are between 9 and 16 bits wide.
Add new functions to properly handle 16-bit brightness in big endian,
since the two 8- and 16-bit cases are distinct from each other.
[richard: use separate functions instead of switch/case]
[richard: split into 16-bit component]
Fixes: 1a9d759331b8 ("drm/dsi: Implement DCS set/get display brightness")
Signed-off-by: Daniel Mentz <danielmentz@xxxxxxxxxx>
Link: https://android.googlesource.com/kernel/msm/+/754affd62d0ee268c686c53169b1dbb7deac8550
[richard: fix 16-bit brightness_get]
Signed-off-by: Richard Acayan <mailingradian@xxxxxxxxx>
Tested-by: Caleb Connolly <caleb@xxxxxxxxxxxxx>
Reviewed-by: Neil Armstrong <neil.armstrong@xxxxxxxxxx>
Reviewed-by: Sam Ravnborg <sam@xxxxxxxxxxxx>
Signed-off-by: Neil Armstrong <neil.armstrong@xxxxxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/20230116224909.23884-2-mailingradian@xxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/gpu/drm/drm_mipi_dsi.c b/drivers/gpu/drm/drm_mipi_dsi.c
index c8c9daecd00da..81923442b42d0 100644
--- a/drivers/gpu/drm/drm_mipi_dsi.c
+++ b/drivers/gpu/drm/drm_mipi_dsi.c
@@ -1096,6 +1096,58 @@ int mipi_dsi_dcs_get_display_brightness(struct mipi_dsi_device *dsi,
}
EXPORT_SYMBOL(mipi_dsi_dcs_get_display_brightness);
+/**
+ * mipi_dsi_dcs_set_display_brightness_large() - sets the 16-bit brightness value
+ * of the display
+ * @dsi: DSI peripheral device
+ * @brightness: brightness value
+ *
+ * Return: 0 on success or a negative error code on failure.
+ */
+int mipi_dsi_dcs_set_display_brightness_large(struct mipi_dsi_device *dsi,
+ u16 brightness)
+{
+ u8 payload[2] = { brightness >> 8, brightness & 0xff };
+ ssize_t err;
+
+ err = mipi_dsi_dcs_write(dsi, MIPI_DCS_SET_DISPLAY_BRIGHTNESS,
+ payload, sizeof(payload));
+ if (err < 0)
+ return err;
+
+ return 0;
+}
+EXPORT_SYMBOL(mipi_dsi_dcs_set_display_brightness_large);
+
+/**
+ * mipi_dsi_dcs_get_display_brightness_large() - gets the current 16-bit
+ * brightness value of the display
+ * @dsi: DSI peripheral device
+ * @brightness: brightness value
+ *
+ * Return: 0 on success or a negative error code on failure.
+ */
+int mipi_dsi_dcs_get_display_brightness_large(struct mipi_dsi_device *dsi,
+ u16 *brightness)
+{
+ u8 brightness_be[2];
+ ssize_t err;
+
+ err = mipi_dsi_dcs_read(dsi, MIPI_DCS_GET_DISPLAY_BRIGHTNESS,
+ brightness_be, sizeof(brightness_be));
+ if (err <= 0) {
+ if (err == 0)
+ err = -ENODATA;
+
+ return err;
+ }
+
+ *brightness = (brightness_be[0] << 8) | brightness_be[1];
+
+ return 0;
+}
+EXPORT_SYMBOL(mipi_dsi_dcs_get_display_brightness_large);
+
static int mipi_dsi_drv_probe(struct device *dev)
{
struct mipi_dsi_driver *drv = to_mipi_dsi_driver(dev->driver);
diff --git a/include/drm/drm_mipi_dsi.h b/include/drm/drm_mipi_dsi.h
index 4fef19064b0f1..689f615471ab1 100644
--- a/include/drm/drm_mipi_dsi.h
+++ b/include/drm/drm_mipi_dsi.h
@@ -274,6 +274,10 @@ int mipi_dsi_dcs_set_display_brightness(struct mipi_dsi_device *dsi,
u16 brightness);
int mipi_dsi_dcs_get_display_brightness(struct mipi_dsi_device *dsi,
u16 *brightness);
+int mipi_dsi_dcs_set_display_brightness_large(struct mipi_dsi_device *dsi,
+ u16 brightness);
+int mipi_dsi_dcs_get_display_brightness_large(struct mipi_dsi_device *dsi,
+ u16 *brightness);
/**
* struct mipi_dsi_driver - DSI driver
