From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from esa.microchip.iphmx.com (esa.microchip.iphmx.com [68.232.154.123]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DC8EC3D75DC; Wed, 13 May 2026 07:18:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=68.232.154.123 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778656709; cv=none; b=KzOmtQBEptc/llHv1OY8XEaOwsCuDr3yu+O27ceOQch4sVIEdjdtJR9is5gkT2dtnd2Gi9jpJWKstningvQwEXIONmI0jg8XDth8UYTFuhdC/GcmvaUMCPJzeoWfQJBqPpefOlcWRV9NXVxJ3cMHLdZhezr9WIDLQcGFKjCDWU4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778656709; c=relaxed/simple; bh=Uq0Wb8JPOoOs2/0x2MV5Z+pFuVJ6FH0ojd6mLoBOmCg=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=dBw9sMh6wCCtJ08eTjMcWOzYTQEH7icDDPrjlR2q5DTmN1hJSQ9Ib2AkV5i0jaSgDpb+6uKaLZzJ43gGq9KnEkwQ9g7YffmBsKhIK01PaoPzJN8TsPLAEha/aFXpI9kctjFIOzjVwSD9x9PUQJYczXWqsWssCOMe3Tl4o30GETI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=microchip.com; spf=pass smtp.mailfrom=microchip.com; dkim=pass (2048-bit key) header.d=microchip.com header.i=@microchip.com header.b=gIdh6qSY; arc=none smtp.client-ip=68.232.154.123 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=microchip.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=microchip.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=microchip.com header.i=@microchip.com header.b="gIdh6qSY" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=microchip.com; i=@microchip.com; q=dns/txt; s=mchp; t=1778656708; x=1810192708; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=Uq0Wb8JPOoOs2/0x2MV5Z+pFuVJ6FH0ojd6mLoBOmCg=; b=gIdh6qSYfmEZULLgt5N++nf3wZIMpPEz6jatm8tBQnQCysvUza2CNC91 7kkRcpEDa30yJA6IpFe68VddeuFtmql9kR3mPqJxAx5kYIp4yDVx3d0Kx bzowXR/SN1T2yTYaWmxHDXpgFjj8qddyJzpHmqFVBCFEnhGbV0gZQr2op 55ieIDXCZImj5p5C+dqh7uNSmb340YyLY9u24IPacgolpOvs8a0aJKqiR 6sv1jRtmNsn6t+s2In9fw5iN7PF6VICWHD//XFYIlHmII4yL5M7+KXwok 3JSfbhBQws6zWXEzLS+V5xQCzDglaDTIzL7DIxrdxmkaWFKQL7L652xaj Q==; X-CSE-ConnectionGUID: dqs3d4p8TWCwjL5e7sGblA== X-CSE-MsgGUID: 92IBeZoyTdeGwRK2fyMI2g== X-IronPort-AV: E=Sophos;i="6.23,232,1770620400"; d="scan'208";a="56656547" X-Amp-Result: SKIPPED(no attachment in message) Received: from unknown (HELO email.microchip.com) ([170.129.1.10]) by esa4.microchip.iphmx.com with ESMTP/TLS/ECDHE-RSA-AES128-GCM-SHA256; 13 May 2026 00:18:27 -0700 Received: from chn-vm-ex01.mchp-main.com (10.10.85.143) by chn-vm-ex04.mchp-main.com (10.10.85.152) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.58; Wed, 13 May 2026 00:18:27 -0700 Received: from che-ll-i71840.microchip.com (10.10.85.11) by chn-vm-ex01.mchp-main.com (10.10.85.143) with Microsoft SMTP Server id 15.1.2507.58 via Frontend Transport; Wed, 13 May 2026 00:18:25 -0700 From: Balakrishnan Sambath To: CC: , , , Subject: [PATCH v3 14/15] media: microchip-isc: smooth AWB gains with EMA filter Date: Wed, 13 May 2026 12:47:41 +0530 Message-ID: <20260513071742.97263-15-balakrishnan.s@microchip.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20260513071742.97263-1-balakrishnan.s@microchip.com> References: <20260512154339.210444-1-balakrishnan.s@microchip.com> <20260513071742.97263-1-balakrishnan.s@microchip.com> Precedence: bulk X-Mailing-List: linux-media@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain Apply exponential moving average (alpha=3D0.25) to reduce per-frame flicker from sensor noise. Signed-off-by: Balakrishnan Sambath --- .../platform/microchip/microchip-isc-base.c | 19 ++++++++++++++++--- .../media/platform/microchip/microchip-isc.h | 1 + 2 files changed, 17 insertions(+), 3 deletions(-) diff --git a/drivers/media/platform/microchip/microchip-isc-base.c b/driver= s/media/platform/microchip/microchip-isc-base.c index ea71cf50eb58..80ae8db1ce01 100644 --- a/drivers/media/platform/microchip/microchip-isc-base.c +++ b/drivers/media/platform/microchip/microchip-isc-base.c @@ -132,6 +132,7 @@ static inline void isc_reset_awb_ctrls(struct isc_devic= e *isc) for (c =3D ISC_HIS_CFG_MODE_GR; c <=3D ISC_HIS_CFG_MODE_B; c++) { /* gains have a fixed point at 9 decimals */ isc->ctrls.gain[c] =3D 1 << 9; + isc->ctrls.gain_smooth[c] =3D 1 << 9; /* offsets are in 2's complements */ isc->ctrls.offset[c] =3D 0; } @@ -1588,11 +1589,23 @@ static void isc_wb_update(struct isc_ctrls *ctrls) /* Combine stretch and grey-world gains; result stays in Q9. */ gain =3D (s_gain * gw_gain) >> 9; =20 - ctrls->gain[c] =3D clamp_val(gain, 0, GENMASK(12, 0)); + /* + * Smooth gain updates with an exponential weighted average + * to suppress per-frame flicker: + * smooth[n] =3D (3 * smooth[n-1] + gain) / 4 + * Clamp to the hardware register width to prevent unbounded + * accumulation under degenerate (near-empty histogram) inputs. + */ + ctrls->gain_smooth[c] =3D (3 * ctrls->gain_smooth[c] + gain) / 4; + ctrls->gain_smooth[c] =3D min_t(u32, ctrls->gain_smooth[c], + GENMASK(12, 0)); + + ctrls->gain[c] =3D ctrls->gain_smooth[c]; =20 dev_dbg(isc->dev, - "isc wb: c=3D%u black=3D%u avg=3D%u s_gain=3D%u gw_gain=3D%u gain=3D%u", - c, hist_min, channel_avg, s_gain, gw_gain, gain); + "isc wb: c=3D%u black=3D%u avg=3D%u s_gain=3D%u gw_gain=3D%u gain=3D%u = smooth=3D%u\n", + c, hist_min, channel_avg, s_gain, gw_gain, gain, + ctrls->gain_smooth[c]); } } =20 diff --git a/drivers/media/platform/microchip/microchip-isc.h b/drivers/med= ia/platform/microchip/microchip-isc.h index 44d54404250d..e558f1a65b33 100644 --- a/drivers/media/platform/microchip/microchip-isc.h +++ b/drivers/media/platform/microchip/microchip-isc.h @@ -155,6 +155,7 @@ struct isc_ctrls { =20 /* one for each component : GR, R, GB, B */ u32 gain[HIST_BAYER]; + u32 gain_smooth[HIST_BAYER]; s32 offset[HIST_BAYER]; =20 u32 hist_entry[HIST_ENTRIES]; --=20 2.34.1