From: Daniel Mentz danielmentz@google.com
[ 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@google.com Link: https://android.googlesource.com/kernel/msm/+/754affd62d0ee268c686c53169b1db... [richard: fix 16-bit brightness_get] Signed-off-by: Richard Acayan mailingradian@gmail.com Tested-by: Caleb Connolly caleb@connolly.tech Reviewed-by: Neil Armstrong neil.armstrong@linaro.org Reviewed-by: Sam Ravnborg sam@ravnborg.org Signed-off-by: Neil Armstrong neil.armstrong@linaro.org Link: https://patchwork.freedesktop.org/patch/msgid/20230116224909.23884-2-mailing... Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/gpu/drm/drm_mipi_dsi.c | 52 ++++++++++++++++++++++++++++++++++ include/drm/drm_mipi_dsi.h | 4 +++ 2 files changed, 56 insertions(+)
diff --git a/drivers/gpu/drm/drm_mipi_dsi.c b/drivers/gpu/drm/drm_mipi_dsi.c index 3ec02748d56fe..f25ddfe37498f 100644 --- a/drivers/gpu/drm/drm_mipi_dsi.c +++ b/drivers/gpu/drm/drm_mipi_dsi.c @@ -1224,6 +1224,58 @@ 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 20b21b577deaa..9054a5185e1a9 100644 --- a/include/drm/drm_mipi_dsi.h +++ b/include/drm/drm_mipi_dsi.h @@ -296,6 +296,10 @@ 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);
/** * mipi_dsi_dcs_write_seq - transmit a DCS command with payload