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SubjectRe: [PATCH 4/7] media: atmel: atmel-isc: add support for DO_WHITE_BALANCE
Date


On 23.04.2019 16:11, Hans Verkuil wrote:
> On 4/15/19 8:43 AM, Eugen.Hristev@microchip.com wrote:
>>
>>
>> On 10.04.2019 17:26, Hans Verkuil wrote:
>>
>>>
>>> On 4/9/19 1:07 PM, Eugen.Hristev@microchip.com wrote:
>>>> From: Eugen Hristev <eugen.hristev@microchip.com>
>>>>
>>>> This adds support for the 'button' control DO_WHITE_BALANCE
>>>> This feature will enable the ISC to compute the white balance coefficients
>>>> in a one time shot, at the user discretion.
>>>> This can be used if a color chart/grey chart is present in front of the camera.
>>>> The ISC will adjust the coefficients and have them fixed until next balance
>>>> or until sensor mode is changed.
>>>> This is particularly useful for white balance adjustment in different
>>>> lighting scenarios, and then taking photos to similar scenery.
>>>> The old auto white balance stays in place, where the ISC will adjust every
>>>> 4 frames to the current scenery lighting, if the scenery is approximately
>>>> grey in average, otherwise grey world algorithm fails.
>>>> One time white balance adjustments needs streaming to be enabled, such that
>>>> capture is enabled and the histogram has data to work with.
>>>> Histogram without capture does not work in this hardware module.
>>>>
>>>> To disable auto white balance feature (first step)
>>>> v4l2-ctl --set-ctrl=white_balance_automatic=0
>>>>
>>>> To start the one time white balance procedure:
>>>> v4l2-ctl --set-ctrl=do_white_balance=1
>>>>
>>>> User controls now include the do_white_balance ctrl:
>>>> User Controls
>>>>
>>>> brightness 0x00980900 (int) : min=-1024 max=1023 step=1 default=0 value=0 flags=slider
>>>> contrast 0x00980901 (int) : min=-2048 max=2047 step=1 default=256 value=256 flags=slider
>>>> white_balance_automatic 0x0098090c (bool) : default=1 value=1
>>>> do_white_balance 0x0098090d (button) : flags=write-only, execute-on-write
>>>> gamma 0x00980910 (int) : min=0 max=2 step=1 default=2 value=2 flags=slider
>>>>
>>>> Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
>>>> ---
>>>> drivers/media/platform/atmel/atmel-isc.c | 74 +++++++++++++++++++++++++++++---
>>>> 1 file changed, 69 insertions(+), 5 deletions(-)
>>>>
>>>> diff --git a/drivers/media/platform/atmel/atmel-isc.c b/drivers/media/platform/atmel/atmel-isc.c
>>>> index f6b8b00e..e516805 100644
>>>> --- a/drivers/media/platform/atmel/atmel-isc.c
>>>> +++ b/drivers/media/platform/atmel/atmel-isc.c
>>>> @@ -167,6 +167,9 @@ struct isc_ctrls {
>>>> u32 brightness;
>>>> u32 contrast;
>>>> u8 gamma_index;
>>>> +#define ISC_WB_NONE 0
>>>> +#define ISC_WB_AUTO 1
>>>> +#define ISC_WB_ONETIME 2
>>>> u8 awb;
>>>>
>>>> /* one for each component : GR, R, GB, B */
>>>> @@ -210,6 +213,7 @@ struct isc_device {
>>>> struct fmt_config try_config;
>>>>
>>>> struct isc_ctrls ctrls;
>>>> + struct v4l2_ctrl *do_wb_ctrl;
>>>> struct work_struct awb_work;
>>>>
>>>> struct mutex lock;
>>>> @@ -809,7 +813,7 @@ static void isc_set_pipeline(struct isc_device *isc, u32 pipeline)
>>>>
>>>> bay_cfg = isc->config.sd_format->cfa_baycfg;
>>>>
>>>> - if (!ctrls->awb)
>>>> + if (ctrls->awb == ISC_WB_NONE)
>>>> isc_reset_awb_ctrls(isc);
>>>>
>>>> regmap_write(regmap, ISC_WB_CFG, bay_cfg);
>>>> @@ -1928,7 +1932,7 @@ static void isc_awb_work(struct work_struct *w)
>>>> baysel = isc->config.sd_format->cfa_baycfg << ISC_HIS_CFG_BAYSEL_SHIFT;
>>>>
>>>> /* if no more auto white balance, reset controls. */
>>>> - if (!ctrls->awb)
>>>> + if (ctrls->awb == ISC_WB_NONE)
>>>> isc_reset_awb_ctrls(isc);
>>>>
>>>> pm_runtime_get_sync(isc->dev);
>>>> @@ -1937,7 +1941,7 @@ static void isc_awb_work(struct work_struct *w)
>>>> * only update if we have all the required histograms and controls
>>>> * if awb has been disabled, we need to reset registers as well.
>>>> */
>>>> - if (hist_id == ISC_HIS_CFG_MODE_GR || !ctrls->awb) {
>>>> + if (hist_id == ISC_HIS_CFG_MODE_GR || ctrls->awb == ISC_WB_NONE) {
>>>> /*
>>>> * It may happen that DMA Done IRQ will trigger while we are
>>>> * updating white balance registers here.
>>>> @@ -1947,6 +1951,16 @@ static void isc_awb_work(struct work_struct *w)
>>>> spin_lock_irqsave(&isc->awb_lock, flags);
>>>> isc_update_awb_ctrls(isc);
>>>> spin_unlock_irqrestore(&isc->awb_lock, flags);
>>>> +
>>>> + /*
>>>> + * if we are doing just the one time white balance adjustment,
>>>> + * we are basically done.
>>>> + */
>>>> + if (ctrls->awb == ISC_WB_ONETIME) {
>>>> + v4l2_info(&isc->v4l2_dev,
>>>> + "Completed one time white-balance adjustment.\n");
>>>> + ctrls->awb = ISC_WB_NONE;
>>>> + }
>>>> }
>>>> regmap_write(regmap, ISC_HIS_CFG, hist_id | baysel | ISC_HIS_CFG_RAR);
>>>> isc_update_profile(isc);
>>>> @@ -1974,10 +1988,56 @@ static int isc_s_ctrl(struct v4l2_ctrl *ctrl)
>>>> ctrls->gamma_index = ctrl->val;
>>>> break;
>>>> case V4L2_CID_AUTO_WHITE_BALANCE:
>>>> - ctrls->awb = ctrl->val;
>>>> + if (ctrl->val == 1) {
>>>> + ctrls->awb = ISC_WB_AUTO;
>>>> + v4l2_ctrl_activate(isc->do_wb_ctrl, false);
>>>> + } else {
>>>> + ctrls->awb = ISC_WB_NONE;
>>>> + v4l2_ctrl_activate(isc->do_wb_ctrl, true);
>>>> + }
>>>> + /* we did not configure ISC yet */
>>>> + if (!isc->config.sd_format)
>>>> + break;
>>>> +
>>>> + if (!ISC_IS_FORMAT_RAW(isc->config.sd_format->mbus_code)) {
>>>> + v4l2_err(&isc->v4l2_dev,
>>>> + "White balance adjustments available only if sensor is in RAW mode.\n");
>>>
>>> This isn't an error, instead if the format isn't raw, then deactivate
>>> the control (see v4l2_ctrl_activate()). That way the control framework
>>> will handle this.
>>>
>>>> + return 0;
>>>> + }
>>>> +
>>>> if (ctrls->hist_stat != HIST_ENABLED) {
>>>> isc_reset_awb_ctrls(isc);
>>>> }
>>>> +
>>>> + if (isc->ctrls.awb && vb2_is_streaming(&isc->vb2_vidq) &&
>>>> + ISC_IS_FORMAT_RAW(isc->config.sd_format->mbus_code))
>>>> + isc_set_histogram(isc, true);
>>>> +
>>>> + break;
>>>> + case V4L2_CID_DO_WHITE_BALANCE:
>>>> + /* we did not configure ISC yet */
>>>> + if (!isc->config.sd_format)
>>>> + break;
>>>> +
>>>> + if (ctrls->awb == ISC_WB_AUTO) {
>>>> + v4l2_err(&isc->v4l2_dev,
>>>> + "To use one time white-balance adjustment, disable auto white balance first.\n");
>>>
>>> I'd do this differently: if auto whitebalance is already on, then just do
>>> nothing for V4L2_CID_DO_WHITE_BALANCE.
>>>
>>>> + return -EAGAIN;
>>>> + }
>>>> + if (!vb2_is_streaming(&isc->vb2_vidq)) {
>>>> + v4l2_err(&isc->v4l2_dev,
>>>> + "One time white-balance adjustment requires streaming to be enabled.\n");
>>>
>>> This too should use v4l2_ctrl_activate(): activate the control in start_streaming,
>>> deactivate in stop_streaming (and when the control is created).
>>>
>>>> + return -EAGAIN;
>>>> + }
>>>> +
>>>> + if (!ISC_IS_FORMAT_RAW(isc->config.sd_format->mbus_code)) {
>>>> + v4l2_err(&isc->v4l2_dev,
>>>> + "White balance adjustments available only if sensor is in RAW mode.\n");
>>>
>>> Same note as above: use v4l2_ctrl_activate() for this.
>>
>> Hello Hans,
>>
>> I used v4l2_ctrl_activate with false parameter, and the v4l2-ctl -l
>> looks like this:
>>
>>
>> do_white_balance (button) : flags=inactive, write-only,
>> execute-on-write
>>
>> But the inactive flag looks to be only for display purposes, as issuing :
>>
>> v4l2-ctl --set-ctrl=do_white_balance=1
>>
>> will continue to call my ctrl callback as if the control is still active.
>>
>> Am I missing something here ? v4l2_s_ctrl does not check for INACTIVE
>> status.
>
> No, you are correct. I got confused with FLAG_GRABBED.
>
> In any case, the idea was right, but you do have to add code to s_ctrl
> to handle this (e.g. if the INACTIVE flag is set, then just do nothing).
>
> The INACTIVE flag is meant to communicate that the control can still be
> set, but it just doesn't do anything. qv4l2 will disable the control if
> this flag is set.
>
> Note that when you set an inactive control, the control value should
> still be updated even if it isn't used at the moment. If the configuration
> changes so that the control becomes active again, then that last set
> value should be used by the hardware.
>
> This is the reason why s_ctrl is still called.

Hello Hans,

Thanks for the explanation. I noticed what you say, and saw other
drivers just exit the s_ctrl if the flag is INACTIVE.
Thus, my latest patch revision does exactly that
https://patchwork.linuxtv.org/patch/55682/

Regarding my specific control (DO_WHITE_BALANCE), it's a button, so it
should really do nothing if control is inactive (no state to save).

Thanks,
Eugen


>
> Regards,
>
> Hans
>
>>
>> Thanks
>>
>>>
>>>> + return -EAGAIN;
>>>> + }
>>>> + ctrls->awb = ISC_WB_ONETIME;
>>>> + isc_set_histogram(isc, true);
>>>> + v4l2_info(&isc->v4l2_dev, "One time white-balance started.\n");
>>>
>>> Make this v4l2_dbg.
>>>
>>>> break;
>>>> default:
>>>> return -EINVAL;
>>>> @@ -2000,7 +2060,7 @@ static int isc_ctrl_init(struct isc_device *isc)
>>>> ctrls->hist_stat = HIST_INIT;
>>>> isc_reset_awb_ctrls(isc);
>>>>
>>>> - ret = v4l2_ctrl_handler_init(hdl, 4);
>>>> + ret = v4l2_ctrl_handler_init(hdl, 5);
>>>> if (ret < 0)
>>>> return ret;
>>>>
>>>> @@ -2012,6 +2072,10 @@ static int isc_ctrl_init(struct isc_device *isc)
>>>> v4l2_ctrl_new_std(hdl, ops, V4L2_CID_GAMMA, 0, GAMMA_MAX, 1, 2);
>>>> v4l2_ctrl_new_std(hdl, ops, V4L2_CID_AUTO_WHITE_BALANCE, 0, 1, 1, 1);
>>>>
>>>> + /* do_white_balance is a button, so min,max,step,default are ignored */
>>>> + isc->do_wb_ctrl = v4l2_ctrl_new_std(hdl, ops, V4L2_CID_DO_WHITE_BALANCE,
>>>> + 0, 0, 0, 0);
>>>> +
>>>> v4l2_ctrl_handler_setup(hdl);
>>>>
>>>> return 0;
>>>>
>>>
>>> Regards,
>>>
>>> Hans
>>>
>
>
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