[media.git/next] media: atomisp: gc0310: Limit max exposure value to mode-height + vblank

[media-ci]

On Sun Jul 6 11:53:53 2025 +0200, Hans de Goede wrote:
> When an exposure value > (mode-height + vblank) gets set the sensor will
> automatically increase vblank, lowering the framerate.
> 
> This is not desirable, limit exposure the maximum exposure to mode-height +
> vblank to avoid the unwanted framerate slowdown.
> 
> Signed-off-by: Hans de Goede <ha...@kernel.org>
> Reviewed-by: Andy Shevchenko <a...@kernel.org>
> Link: https://lore.kernel.org/r/20250517114106.43494-11-hdego...@redhat.com
> Signed-off-by: Mauro Carvalho Chehab <mchehab+hua...@kernel.org>

Patch committed.

Thanks,
Mauro Carvalho Chehab

 drivers/staging/media/atomisp/i2c/atomisp-gc0310.c | 21 +++++++++++++++++++--
 1 file changed, 19 insertions(+), 2 deletions(-)

---

diff --git a/drivers/staging/media/atomisp/i2c/atomisp-gc0310.c 
b/drivers/staging/media/atomisp/i2c/atomisp-gc0310.c
index d0e7f0f8452b..3e94414be6c7 100644
--- a/drivers/staging/media/atomisp/i2c/atomisp-gc0310.c
+++ b/drivers/staging/media/atomisp/i2c/atomisp-gc0310.c
@@ -306,12 +306,27 @@ static int gc0310_gain_set(struct gc0310_device *sensor, 
u32 gain)
        return ret;
 }
 
+static int gc0310_exposure_update_range(struct gc0310_device *sensor)
+{
+       int exp_max = GC0310_NATIVE_HEIGHT + sensor->ctrls.vblank->val;
+
+       return __v4l2_ctrl_modify_range(sensor->ctrls.exposure, 0, exp_max,
+                                       1, exp_max);
+}
+
 static int gc0310_s_ctrl(struct v4l2_ctrl *ctrl)
 {
        struct gc0310_device *sensor =
                container_of(ctrl->handler, struct gc0310_device, 
ctrls.handler);
        int ret;
 
+       /* Update exposure range on vblank changes */
+       if (ctrl->id == V4L2_CID_VBLANK) {
+               ret = gc0310_exposure_update_range(sensor);
+               if (ret)
+                       return ret;
+       }
+
        /* Only apply changes to the controls if the device is powered up */
        if (!pm_runtime_get_if_in_use(sensor->sd.dev))
                return 0;
@@ -584,7 +599,7 @@ static int gc0310_init_controls(struct gc0310_device 
*sensor)
        struct i2c_client *client = v4l2_get_subdevdata(&sensor->sd);
        struct v4l2_ctrl_handler *hdl = &sensor->ctrls.handler;
        struct v4l2_fwnode_device_properties props;
-       int ret;
+       int exp_max, ret;
 
        v4l2_ctrl_handler_init(hdl, 8);
 
@@ -592,8 +607,10 @@ static int gc0310_init_controls(struct gc0310_device 
*sensor)
        hdl->lock = &sensor->input_lock;
        sensor->sd.ctrl_handler = hdl;
 
+       exp_max = GC0310_NATIVE_HEIGHT + GC0310_V_BLANK_DEFAULT;
        sensor->ctrls.exposure =
-               v4l2_ctrl_new_std(hdl, &ctrl_ops, V4L2_CID_EXPOSURE, 0, 4095, 
1, 1023);
+               v4l2_ctrl_new_std(hdl, &ctrl_ops, V4L2_CID_EXPOSURE, 0,
+                                 exp_max, 1, exp_max);
 
        /* 32 steps at base gain 1 + 64 half steps at base gain 2 */
        sensor->ctrls.gain =