[PATCH v4 00/12] media: microchip-isc: fixes and enhancements

[PATCH v4 00/12] media: microchip-isc: fixes and enhancements

[Balakrishnan Sambath]

Bug fixes and feature additions for the Microchip ISC/XISC driver.

Fixes:
 - SBGGR10 Bayer pattern was mapped incorrectly (red/blue swap)
 - WB register fields corrupted by sign extension
 - Race between histogram IRQ and stream stop
 - PM runtime reference leak in AWB work handler

Features:
 - Driver documentation
 - Gamma 1.8/2.4 preset curves
 - Hue/saturation controls for SAMA7G5
 - Grey World AWB with EMA smoothing

Split from v1 per review. Histogram statistics support is being sent
as a separate follow-up series.

Tested on SAMA7G5-EK with IMX219 (RAW10 Bayer capture, AWB, controls
verified across 8 formats and 5 resolutions up to 3264x2464).

Based on v6.19 (e9ec05addd1a).

v1: https://lore.kernel.org/linux-media/20251009155251.102472-1-balamanikandan.gunasundar@microchip.com/
v2: https://lore.kernel.org/linux-media/20260512154339.210444-1-balakrishnan.s@microchip.com/
v3: https://lore.kernel.org/linux-media/20260513071742.97263-1-balakrishnan.s@microchip.com/

v4:
 - Drop gamma LUT controls and CC matrix V4L2 controls patches (move
   to parameter buffer follow-up per Sakari's review)
 - Drop AWB enable pipeline reset patch (cleanup for the dropped
   controls, will return with the follow-up series)
 - Update documentation patch to remove references to dropped controls
 - Rebase on v6.19

v3:
 - Fix bisect failures (regmap declaration, gamma LUT macro ordering)
 - Fix Fixes: tag (use mainline commit, not staging)
 - Add Co-developed-by trailers for Balamanikandan Gunasundar

v2:
 - Split series (histogram stats moved to a separate follow-up series)
 - Reorder: bug fixes first, then features
 - Commit message cleanups
 - Rebase on v6.19-rc8

Signed-off-by: Balakrishnan Sambath <balakrishnan.s@microchip.com>
---
Balakrishnan Sambath (12):
      media: microchip-isc: fix SBGGR10 Bayer pattern
      media: microchip-isc: mask WB offset and gain register fields
      media: microchip-isc: fix race condition on stream stop
      media: microchip-isc: fix PM runtime leak in AWB work handler
      media: microchip-isc: add driver documentation
      media: microchip-isc: set SAM9X7 maximum resolution to 2560x1920
      media: microchip-isc: configure DPC and pipeline for SAMA7G5
      media: microchip-isc: add gamma 1.8 and 2.4 correction curves
      media: microchip-isc: add SAMA7G5 hue and saturation controls
      media: microchip-isc: use weighted averages for Grey World AWB
      media: microchip-isc: smooth AWB gains with EMA filter
      media: microchip-isc: scale DPC black level to sensor bit depth

 .../userspace-api/media/drivers/index.rst          |   1 +
 .../userspace-api/media/drivers/microchip-isc.rst  |  66 +++++
 MAINTAINERS                                        |   1 +
 .../media/platform/microchip/microchip-isc-base.c  | 320 ++++++++++++++++-----
 .../media/platform/microchip/microchip-isc-regs.h  |  11 +-
 drivers/media/platform/microchip/microchip-isc.h   |   8 +-
 .../platform/microchip/microchip-sama5d2-isc.c     |   2 +-
 .../platform/microchip/microchip-sama7g5-isc.c     | 100 +++++--
 8 files changed, 413 insertions(+), 96 deletions(-)
---
base-commit: 05f7e89ab9731565d8a62e3b5d1ec206485eeb0b
change-id: 20260518-balki-isc-series1-v4-1eeaa50a9f84

Best regards,
-- 
Balakrishnan Sambath <balakrishnan.s@microchip.com>

[PATCH v4 01/12] media: microchip-isc: fix SBGGR10 Bayer pattern

[Balakrishnan Sambath]

SBGGR10 was mapped to ISC_BAY_CFG_RGRG instead of ISC_BAY_CFG_BGBG,
causing red/blue channel swap.

Fixes: 91b4e487b0c6 ("media: microchip: add ISC driver as Microchip ISC")
Cc: stable@vger.kernel.org
Signed-off-by: Balakrishnan Sambath <balakrishnan.s@microchip.com>
---
 drivers/media/platform/microchip/microchip-sama7g5-isc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/media/platform/microchip/microchip-sama7g5-isc.c b/drivers/media/platform/microchip/microchip-sama7g5-isc.c
index b0302dfc3278..ca23e8adecbd 100644
--- a/drivers/media/platform/microchip/microchip-sama7g5-isc.c
+++ b/drivers/media/platform/microchip/microchip-sama7g5-isc.c
@@ -156,7 +156,7 @@ static struct isc_format sama7g5_formats_list[] = {
 		.fourcc		= V4L2_PIX_FMT_SBGGR10,
 		.mbus_code	= MEDIA_BUS_FMT_SBGGR10_1X10,
 		.pfe_cfg0_bps	= ISC_PFG_CFG0_BPS_TEN,
-		.cfa_baycfg	= ISC_BAY_CFG_RGRG,
+		.cfa_baycfg	= ISC_BAY_CFG_BGBG,
 	},
 	{
 		.fourcc		= V4L2_PIX_FMT_SGBRG10,

-- 
2.34.1

[PATCH v4 02/12] media: microchip-isc: mask WB offset and gain register fields

[Balakrishnan Sambath]

ISC_WB_O_* and ISC_WB_G_* pack two 13-bit fields per register. Sign
extension from negative offsets corrupts the upper field. Mask both
fields to 13 bits before packing.

Fixes: 91b4e487b0c6 ("media: microchip: add ISC driver as Microchip ISC")
Cc: stable@vger.kernel.org
Signed-off-by: Balakrishnan Sambath <balakrishnan.s@microchip.com>
---
 .../media/platform/microchip/microchip-isc-base.c   | 21 +++++++++++++--------
 1 file changed, 13 insertions(+), 8 deletions(-)

diff --git a/drivers/media/platform/microchip/microchip-isc-base.c b/drivers/media/platform/microchip/microchip-isc-base.c
index a7cdc743fda7..45b94f1e89d8 100644
--- a/drivers/media/platform/microchip/microchip-isc-base.c
+++ b/drivers/media/platform/microchip/microchip-isc-base.c
@@ -61,18 +61,23 @@ static inline void isc_update_awb_ctrls(struct isc_device *isc)
 
 	/* In here we set our actual hw pipeline config */
 
+	/*
+	 * Mask offset fields to 13 bits. Sign extension of negative s32
+	 * values would otherwise corrupt the adjacent field.
+	 */
 	regmap_write(isc->regmap, ISC_WB_O_RGR,
-		     ((ctrls->offset[ISC_HIS_CFG_MODE_R])) |
-		     ((ctrls->offset[ISC_HIS_CFG_MODE_GR]) << 16));
+		     ((u32)ctrls->offset[ISC_HIS_CFG_MODE_R] & GENMASK(12, 0)) |
+		     (((u32)ctrls->offset[ISC_HIS_CFG_MODE_GR] & GENMASK(12, 0)) << 16));
 	regmap_write(isc->regmap, ISC_WB_O_BGB,
-		     ((ctrls->offset[ISC_HIS_CFG_MODE_B])) |
-		     ((ctrls->offset[ISC_HIS_CFG_MODE_GB]) << 16));
+		     ((u32)ctrls->offset[ISC_HIS_CFG_MODE_B] & GENMASK(12, 0)) |
+		     (((u32)ctrls->offset[ISC_HIS_CFG_MODE_GB] & GENMASK(12, 0)) << 16));
+	/* Gains are 13-bit unsigned fields [12:0] and [28:16] */
 	regmap_write(isc->regmap, ISC_WB_G_RGR,
-		     ctrls->gain[ISC_HIS_CFG_MODE_R] |
-		     (ctrls->gain[ISC_HIS_CFG_MODE_GR] << 16));
+		     (ctrls->gain[ISC_HIS_CFG_MODE_R] & GENMASK(12, 0)) |
+		     ((ctrls->gain[ISC_HIS_CFG_MODE_GR] & GENMASK(12, 0)) << 16));
 	regmap_write(isc->regmap, ISC_WB_G_BGB,
-		     ctrls->gain[ISC_HIS_CFG_MODE_B] |
-		     (ctrls->gain[ISC_HIS_CFG_MODE_GB] << 16));
+		     (ctrls->gain[ISC_HIS_CFG_MODE_B] & GENMASK(12, 0)) |
+		     ((ctrls->gain[ISC_HIS_CFG_MODE_GB] & GENMASK(12, 0)) << 16));
 }
 
 static inline void isc_reset_awb_ctrls(struct isc_device *isc)

-- 
2.34.1

[PATCH v4 03/12] media: microchip-isc: fix race condition on stream stop

[Balakrishnan Sambath]

Disable histogram and drain AWB work queue before releasing DMA
buffers to prevent use-after-free if histogram IRQ fires during
stream stop.

Fixes: 91b4e487b0c6 ("media: microchip: add ISC driver as Microchip ISC")
Cc: stable@vger.kernel.org
Signed-off-by: Balakrishnan Sambath <balakrishnan.s@microchip.com>
---
 drivers/media/platform/microchip/microchip-isc-base.c | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/drivers/media/platform/microchip/microchip-isc-base.c b/drivers/media/platform/microchip/microchip-isc-base.c
index 45b94f1e89d8..b19c5a63b4bd 100644
--- a/drivers/media/platform/microchip/microchip-isc-base.c
+++ b/drivers/media/platform/microchip/microchip-isc-base.c
@@ -427,6 +427,14 @@ static void isc_stop_streaming(struct vb2_queue *vq)
 
 	mutex_unlock(&isc->awb_mutex);
 
+	/*
+	 * Disable the histogram so the ISR stops firing HISREQ, then drain
+	 * any work that was already queued before returning.  This must happen
+	 * after releasing awb_mutex because isc_awb_work also takes it.
+	 */
+	isc_set_histogram(isc, false);
+	cancel_work_sync(&isc->awb_work);
+
 	/* Disable DMA interrupt */
 	regmap_write(isc->regmap, ISC_INTDIS, ISC_INT_DDONE);
 
@@ -1519,10 +1527,17 @@ static int isc_s_awb_ctrl(struct v4l2_ctrl *ctrl)
 		}
 		mutex_unlock(&isc->awb_mutex);
 
-		/* if we have autowhitebalance on, start histogram procedure */
+		/*
+		 * If AWB auto mode is requested and we are streaming RAW,
+		 * start the histogram procedure, but only if it is not
+		 * already running. Repeated enable requests would reset
+		 * hist_id, preventing the 4-channel Bayer cycle from
+		 * completing.
+		 */
 		if (ctrls->awb == ISC_WB_AUTO &&
 		    vb2_is_streaming(&isc->vb2_vidq) &&
-		    ISC_IS_FORMAT_RAW(isc->config.sd_format->mbus_code))
+		    ISC_IS_FORMAT_RAW(isc->config.sd_format->mbus_code) &&
+		    ctrls->hist_stat != HIST_ENABLED)
 			isc_set_histogram(isc, true);
 
 		/*

-- 
2.34.1

[PATCH v4 04/12] media: microchip-isc: fix PM runtime leak in AWB work handler

[Balakrishnan Sambath]

Early return when streaming stops skips pm_runtime_put_sync(),
leaking the reference and preventing runtime suspend.

Fixes: 91b4e487b0c6 ("media: microchip: add ISC driver as Microchip ISC")
Cc: stable@vger.kernel.org
Signed-off-by: Balakrishnan Sambath <balakrishnan.s@microchip.com>
---
 drivers/media/platform/microchip/microchip-isc-base.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/media/platform/microchip/microchip-isc-base.c b/drivers/media/platform/microchip/microchip-isc-base.c
index b19c5a63b4bd..f61a5d5a3e04 100644
--- a/drivers/media/platform/microchip/microchip-isc-base.c
+++ b/drivers/media/platform/microchip/microchip-isc-base.c
@@ -1429,7 +1429,7 @@ static void isc_awb_work(struct work_struct *w)
 	/* streaming is not active anymore */
 	if (isc->stop) {
 		mutex_unlock(&isc->awb_mutex);
-		return;
+		goto out_pm_put;
 	}
 
 	isc_update_profile(isc);
@@ -1440,6 +1440,7 @@ static void isc_awb_work(struct work_struct *w)
 	if (ctrls->awb)
 		regmap_write(regmap, ISC_CTRLEN, ISC_CTRL_HISREQ);
 
+out_pm_put:
 	pm_runtime_put_sync(isc->dev);
 }
 

-- 
2.34.1

[PATCH v4 05/12] media: microchip-isc: add driver documentation

[Balakrishnan Sambath]

Document V4L2 controls and pipeline modes for ISC/XISC camera interface
on SAMA5D2, SAMA7G5, and SAM9X7.

Signed-off-by: Balakrishnan Sambath <balakrishnan.s@microchip.com>
---
 .../userspace-api/media/drivers/index.rst          |  1 +
 .../userspace-api/media/drivers/microchip-isc.rst  | 66 ++++++++++++++++++++++
 MAINTAINERS                                        |  1 +
 3 files changed, 68 insertions(+)

diff --git a/Documentation/userspace-api/media/drivers/index.rst b/Documentation/userspace-api/media/drivers/index.rst
index 02967c9b18d6..65ef6ba3523e 100644
--- a/Documentation/userspace-api/media/drivers/index.rst
+++ b/Documentation/userspace-api/media/drivers/index.rst
@@ -34,6 +34,7 @@ For more details see the file COPYING in the source distribution of Linux.
 	imx-uapi
 	mali-c55
 	max2175
+	microchip-isc
 	npcm-video
 	omap3isp-uapi
 	thp7312
diff --git a/Documentation/userspace-api/media/drivers/microchip-isc.rst b/Documentation/userspace-api/media/drivers/microchip-isc.rst
new file mode 100644
index 000000000000..e065ae009595
--- /dev/null
+++ b/Documentation/userspace-api/media/drivers/microchip-isc.rst
@@ -0,0 +1,66 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+Microchip ISC/XISC Driver
+=========================
+
+The Image Sensor Controller (ISC) on SAMA5D2 and eXtended ISC (XISC) on
+SAMA7G5/SAM9X7 provide camera capture with hardware image processing.
+
+Supported Hardware
+------------------
+
+==========  ==========  ==============  ================  ===============
+SoC         Controller  Max Resolution  Interface         Hue/Saturation
+==========  ==========  ==============  ================  ===============
+SAMA5D2     ISC         2592x1944       12-bit parallel   No
+SAMA7G5     XISC        3264x2464       12-bit + CSI-2    Yes
+SAM9X7      XISC        2560x1920       12-bit + CSI-2    Yes
+==========  ==========  ==============  ================  ===============
+
+SAM9X7 shares the XISC pipeline with SAMA7G5 but has a smaller internal
+line buffer, limiting horizontal resolution to 2560 pixels.
+
+Controls
+--------
+
+Standard V4L2 controls:
+
+* ``V4L2_CID_BRIGHTNESS``: -1024..1023, default 0
+* ``V4L2_CID_CONTRAST``: -2048..2047, default 256 (1.0x)
+* ``V4L2_CID_GAMMA``: 0..2 selects curve (0=2.4, 1=2.2, 2=1.8)
+* ``V4L2_CID_AUTO_WHITE_BALANCE``: Enable kernel Grey World AWB
+* ``V4L2_CID_DO_WHITE_BALANCE``: Trigger one-shot AWB
+
+SAMA7G5/SAM9X7 add:
+
+* ``V4L2_CID_HUE``: -180..180 degrees
+* ``V4L2_CID_SATURATION``: 0..255, default 16
+
+Custom controls (defined in ``atmel-isc-media.h``):
+
+* ``ISC_CID_R_GAIN``, ``ISC_CID_B_GAIN``, ``ISC_CID_GR_GAIN``,
+  ``ISC_CID_GB_GAIN``: WB gains, 0..8191, Q2.9 (512 = 1.0x)
+* ``ISC_CID_R_OFFSET``, ``ISC_CID_B_OFFSET``, ``ISC_CID_GR_OFFSET``,
+  ``ISC_CID_GB_OFFSET``: WB offsets, -4096..4095
+
+Pipeline
+--------
+
+Pipeline modules: DPC -> WB -> CFA -> CC -> GAM -> CBHS/CBC -> CSC -> SUB
+
+* DPC: Defective Pixel Correction (XISC only), black level subtraction
+  to sensor bit depth, green disparity correction
+* WB: White Balance gains/offsets
+* CFA: Color Filter Array interpolation (demosaic)
+* CC: Color Correction matrix
+* GAM: Gamma correction (preset)
+* CBHS: Contrast/Brightness/Hue/Saturation (XISC only)
+* CBC: Contrast/Brightness (ISC only)
+* CSC: Color Space Conversion (RGB to YCbCr)
+* SUB: Chroma subsampling (4:2:2, 4:2:0)
+
+Pipeline usage depends on input and output formats:
+
+* Raw Bayer input, RGB output: DPC, WB, CFA, CC, GAM
+* Raw Bayer input, YUV output: Full pipeline including CSC, CBHS/CBC, SUB
+* Non-RAW input (YUV/RGB sensor): Pipeline bypassed
diff --git a/MAINTAINERS b/MAINTAINERS
index e08767323763..d4aa7e86e2bd 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -17057,6 +17057,7 @@ L:	linux-media@vger.kernel.org
 S:	Supported
 F:	Documentation/devicetree/bindings/media/atmel,isc.yaml
 F:	Documentation/devicetree/bindings/media/microchip,xisc.yaml
+F:	Documentation/userspace-api/media/drivers/microchip-isc.rst
 F:	drivers/media/platform/microchip/microchip-isc*
 F:	drivers/media/platform/microchip/microchip-sama*-isc*
 F:	drivers/staging/media/deprecated/atmel/atmel-isc*

-- 
2.34.1

[PATCH v4 06/12] media: microchip-isc: set SAM9X7 maximum resolution to 2560x1920

[Balakrishnan Sambath]

SAM9X7 XISC uses the same image processing pipeline as SAMA7G5 but has
a smaller internal line buffer. The reduced RAM constrains the maximum
horizontal resolution to 2560 pixels (compared to 3264 on SAMA7G5),
resulting in a maximum capture resolution of 2560x1920.

Co-developed-by: Balamanikandan Gunasundar <balamanikandan.gunasundar@microchip.com>
Signed-off-by: Balamanikandan Gunasundar <balamanikandan.gunasundar@microchip.com>
Signed-off-by: Balakrishnan Sambath <balakrishnan.s@microchip.com>
---
 drivers/media/platform/microchip/microchip-sama7g5-isc.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/media/platform/microchip/microchip-sama7g5-isc.c b/drivers/media/platform/microchip/microchip-sama7g5-isc.c
index ca23e8adecbd..4119cfe12cdf 100644
--- a/drivers/media/platform/microchip/microchip-sama7g5-isc.c
+++ b/drivers/media/platform/microchip/microchip-sama7g5-isc.c
@@ -55,6 +55,9 @@
 #define ISC_SAMA7G5_MAX_SUPPORT_WIDTH   3264
 #define ISC_SAMA7G5_MAX_SUPPORT_HEIGHT  2464
 
+#define ISC_SAM9X7_MAX_SUPPORT_WIDTH    2560
+#define ISC_SAM9X7_MAX_SUPPORT_HEIGHT   1920
+
 #define ISC_SAMA7G5_PIPELINE \
 	(WB_ENABLE | CFA_ENABLE | CC_ENABLE | GAM_ENABLES | CSC_ENABLE | \
 	CBC_ENABLE | SUB422_ENABLE | SUB420_ENABLE)
@@ -432,8 +435,13 @@ static int microchip_xisc_probe(struct platform_device *pdev)
 	isc->gamma_table = isc_sama7g5_gamma_table;
 	isc->gamma_max = 0;
 
-	isc->max_width = ISC_SAMA7G5_MAX_SUPPORT_WIDTH;
-	isc->max_height = ISC_SAMA7G5_MAX_SUPPORT_HEIGHT;
+	if (of_machine_is_compatible("microchip,sam9x7")) {
+		isc->max_width = ISC_SAM9X7_MAX_SUPPORT_WIDTH;
+		isc->max_height = ISC_SAM9X7_MAX_SUPPORT_HEIGHT;
+	} else {
+		isc->max_width = ISC_SAMA7G5_MAX_SUPPORT_WIDTH;
+		isc->max_height = ISC_SAMA7G5_MAX_SUPPORT_HEIGHT;
+	}
 
 	isc->config_dpc = isc_sama7g5_config_dpc;
 	isc->config_csc = isc_sama7g5_config_csc;

-- 
2.34.1

[PATCH v4 07/12] media: microchip-isc: configure DPC and pipeline for SAMA7G5

[Balakrishnan Sambath]

Enable DPC_GDCENABLE for RGB output. Disable pipeline for raw Bayer
passthrough to provide unmodified sensor data for software ISP.

Co-developed-by: Balamanikandan Gunasundar <balamanikandan.gunasundar@microchip.com>
Signed-off-by: Balamanikandan Gunasundar <balamanikandan.gunasundar@microchip.com>
Signed-off-by: Balakrishnan Sambath <balakrishnan.s@microchip.com>
---
 drivers/media/platform/microchip/microchip-isc-base.c    | 7 ++-----
 drivers/media/platform/microchip/microchip-sama7g5-isc.c | 3 ++-
 2 files changed, 4 insertions(+), 6 deletions(-)

diff --git a/drivers/media/platform/microchip/microchip-isc-base.c b/drivers/media/platform/microchip/microchip-isc-base.c
index f61a5d5a3e04..23a09ed12946 100644
--- a/drivers/media/platform/microchip/microchip-isc-base.c
+++ b/drivers/media/platform/microchip/microchip-isc-base.c
@@ -800,7 +800,7 @@ static int isc_try_configure_pipeline(struct isc_device *isc)
 		if (ISC_IS_FORMAT_RAW(isc->try_config.sd_format->mbus_code)) {
 			isc->try_config.bits_pipeline = CFA_ENABLE |
 				WB_ENABLE | GAM_ENABLES | DPC_BLCENABLE |
-				CC_ENABLE;
+				DPC_GDCENABLE | CC_ENABLE;
 		} else {
 			isc->try_config.bits_pipeline = 0x0;
 		}
@@ -850,10 +850,7 @@ static int isc_try_configure_pipeline(struct isc_device *isc)
 		}
 		break;
 	default:
-		if (ISC_IS_FORMAT_RAW(isc->try_config.sd_format->mbus_code))
-			isc->try_config.bits_pipeline = WB_ENABLE | DPC_BLCENABLE;
-		else
-			isc->try_config.bits_pipeline = 0x0;
+		isc->try_config.bits_pipeline = 0x0;
 	}
 
 	/* Tune the pipeline to product specific */
diff --git a/drivers/media/platform/microchip/microchip-sama7g5-isc.c b/drivers/media/platform/microchip/microchip-sama7g5-isc.c
index 4119cfe12cdf..04930aa0f289 100644
--- a/drivers/media/platform/microchip/microchip-sama7g5-isc.c
+++ b/drivers/media/platform/microchip/microchip-sama7g5-isc.c
@@ -59,7 +59,8 @@
 #define ISC_SAM9X7_MAX_SUPPORT_HEIGHT   1920
 
 #define ISC_SAMA7G5_PIPELINE \
-	(WB_ENABLE | CFA_ENABLE | CC_ENABLE | GAM_ENABLES | CSC_ENABLE | \
+	(DPC_DPCENABLE | DPC_GDCENABLE | DPC_BLCENABLE | \
+	WB_ENABLE | CFA_ENABLE | CC_ENABLE | GAM_ENABLES | CSC_ENABLE | \
 	CBC_ENABLE | SUB422_ENABLE | SUB420_ENABLE)
 
 /* This is a list of the formats that the ISC can *output* */

-- 
2.34.1

[PATCH v4 08/12] media: microchip-isc: add gamma 1.8 and 2.4 correction curves

[Balakrishnan Sambath]

Add gamma 1.8 and 2.4 curves alongside the existing 2.2 (sRGB).
V4L2_CID_GAMMA selects preset curves: 0=2.4, 1=2.2, 2=1.8.

Co-developed-by: Balamanikandan Gunasundar <balamanikandan.gunasundar@microchip.com>
Signed-off-by: Balamanikandan Gunasundar <balamanikandan.gunasundar@microchip.com>
Signed-off-by: Balakrishnan Sambath <balakrishnan.s@microchip.com>
---
 .../media/platform/microchip/microchip-isc-base.c  |  3 +-
 .../platform/microchip/microchip-sama7g5-isc.c     | 54 ++++++++++++++++------
 2 files changed, 41 insertions(+), 16 deletions(-)

diff --git a/drivers/media/platform/microchip/microchip-isc-base.c b/drivers/media/platform/microchip/microchip-isc-base.c
index 23a09ed12946..ae2a0c6ba566 100644
--- a/drivers/media/platform/microchip/microchip-isc-base.c
+++ b/drivers/media/platform/microchip/microchip-isc-base.c
@@ -1647,8 +1647,7 @@ static int isc_ctrl_init(struct isc_device *isc)
 	ctrls->brightness = 0;
 
 	v4l2_ctrl_new_std(hdl, ops, V4L2_CID_BRIGHTNESS, -1024, 1023, 1, 0);
-	v4l2_ctrl_new_std(hdl, ops, V4L2_CID_GAMMA, 0, isc->gamma_max, 1,
-			  isc->gamma_max);
+	v4l2_ctrl_new_std(hdl, ops, V4L2_CID_GAMMA, 0, isc->gamma_max, 1, 1);
 	isc->awb_ctrl = v4l2_ctrl_new_std(hdl, &isc_awb_ops,
 					  V4L2_CID_AUTO_WHITE_BALANCE,
 					  0, 1, 1, 1);
diff --git a/drivers/media/platform/microchip/microchip-sama7g5-isc.c b/drivers/media/platform/microchip/microchip-sama7g5-isc.c
index 04930aa0f289..8b73b625d92b 100644
--- a/drivers/media/platform/microchip/microchip-sama7g5-isc.c
+++ b/drivers/media/platform/microchip/microchip-sama7g5-isc.c
@@ -320,21 +320,47 @@ static void isc_sama7g5_adapt_pipeline(struct isc_device *isc)
 	isc->try_config.bits_pipeline &= ISC_SAMA7G5_PIPELINE;
 }
 
-/* Gamma table with gamma 1/2.2 */
+/* Gamma tables with gamma values 0.42, 0.45(Default), 0.56 */
 static const u32 isc_sama7g5_gamma_table[][GAMMA_ENTRIES] = {
-	/* index 0 --> gamma bipartite */
+	/* index 0 --> gamma bipartite 1/2.4(=0.42) */
 	{
-	      0x980,  0x4c0320,  0x650260,  0x7801e0,  0x8701a0,  0x940180,
-	   0xa00160,  0xab0120,  0xb40120,  0xbd0120,  0xc60100,  0xce0100,
-	   0xd600e0,  0xdd00e0,  0xe400e0,  0xeb00c0,  0xf100c0,  0xf700c0,
-	   0xfd00c0, 0x10300a0, 0x10800c0, 0x10e00a0, 0x11300a0, 0x11800a0,
-	  0x11d00a0, 0x12200a0, 0x12700a0, 0x12c0080, 0x13000a0, 0x1350080,
-	  0x13900a0, 0x13e0080, 0x1420076, 0x17d0062, 0x1ae0054, 0x1d8004a,
-	  0x1fd0044, 0x21f003e, 0x23e003a, 0x25b0036, 0x2760032, 0x28f0030,
-	  0x2a7002e, 0x2be002c, 0x2d4002c, 0x2ea0028, 0x2fe0028, 0x3120026,
-	  0x3250024, 0x3370024, 0x3490022, 0x35a0022, 0x36b0020, 0x37b0020,
-	  0x38b0020, 0x39b001e, 0x3aa001e, 0x3b9001c, 0x3c7001c, 0x3d5001c,
-	  0x3e3001c, 0x3f1001c, 0x3ff001a, 0x40c001a },
+	      0x940,  0x4b0310,  0x630250,  0x7601d0,  0x840190,  0x910170,
+	   0x9d0150,  0xa80110,  0xb10110,  0xba0110,  0xc300f0,  0xcb00f0,
+	   0xd300e0,  0xda00e0,  0xe100c0,  0xe800c0,  0xee00c0,  0xf400c0,
+	   0xfa00a0, 0x10000a0, 0x10500a0, 0x10b00a0, 0x11000a0, 0x11500a0,
+	  0x11a0080, 0x11f0080, 0x1240080, 0x1290080, 0x12e0080, 0x1330070,
+	  0x1380070, 0x13c0070, 0x1410070, 0x17a0060, 0x1aa0052, 0x1d40046,
+	  0x1f90042, 0x21b003c, 0x23a0038, 0x2570034, 0x2720030, 0x28b002e,
+	  0x2a3002c, 0x2ba002a, 0x2d0002a, 0x2e60028, 0x2fa0026, 0x30e0026,
+	  0x3210024, 0x3330022, 0x3450022, 0x3560020, 0x3670020, 0x3770020,
+	  0x387001e, 0x396001e, 0x3a5001c, 0x3b3001c, 0x3c1001c, 0x3cf001a,
+	  0x3dd001a, 0x3eb0018, 0x3f90018, 0x4070016 },
+	/* index 1 --> gamma bipartite 1/2.2(=0.45) */
+	{
+	     0x980,  0x4c0320,  0x650260,  0x7801e0,  0x8701a0,  0x940180,
+	  0xa00160,  0xab0120,  0xb40120,  0xbd0120,  0xc60100,  0xce0100,
+	  0xd600e0,  0xdd00e0,  0xe400e0,  0xeb00c0,  0xf100c0,  0xf700c0,
+	  0xfd00c0, 0x10300a0, 0x10800c0, 0x10e00a0, 0x11300a0, 0x11800a0,
+	 0x11d00a0, 0x12200a0, 0x12700a0, 0x12c0080, 0x13000a0, 0x1350080,
+	 0x13900a0, 0x13e0080, 0x1420076, 0x17d0062, 0x1ae0054, 0x1d8004a,
+	 0x1fd0044, 0x21f003e, 0x23e003a, 0x25b0036, 0x2760032, 0x28f0030,
+	 0x2a7002e, 0x2be002c, 0x2d4002c, 0x2ea0028, 0x2fe0028, 0x3120026,
+	 0x3250024, 0x3370024, 0x3490022, 0x35a0022, 0x36b0020, 0x37b0020,
+	 0x38b0020, 0x39b001e, 0x3aa001e, 0x3b9001c, 0x3c7001c, 0x3d5001c,
+	 0x3e3001c, 0x3f1001c, 0x3ff001a, 0x40c001a },
+	/* index 2 --> gamma bipartite 1/1.8(=0.56) */
+	{
+	      0xa62,  0x4f0350,  0x680280,  0x7e0200,  0x8d01c0,  0x9a01a0,
+	   0xa50180,  0xb00140,  0xb90140,  0xc20120,  0xcb0120,  0xd30100,
+	   0xdb0100,  0xe300e0,  0xea00e0,  0xf100e0,  0xf700c0,  0xfd00c0,
+	  0x10300c0, 0x10900a0, 0x10e00a0, 0x11400a0, 0x11900a0, 0x11e00a0,
+	  0x12300a0, 0x12800a0, 0x12d0080, 0x1320080, 0x1370080, 0x13c0080,
+	  0x1410080, 0x1460080, 0x14a0070, 0x1830060, 0x1b40052, 0x1df0048,
+	  0x2040042, 0x2250040, 0x2440038, 0x2600036, 0x27b0032, 0x2940030,
+	  0x2ac002e, 0x2c4002c, 0x2da002a, 0x2f0002a, 0x3050028, 0x3190026,
+	  0x32c0026, 0x33e0024, 0x3500024, 0x3610022, 0x3720020, 0x3820020,
+	  0x3920020, 0x3a2001e, 0x3b1001e, 0x3c0001c, 0x3ce001c, 0x3dc001c,
+	  0x3ea001a, 0x3f8001a, 0x4060018, 0x4130018 },
 };
 
 static int xisc_parse_dt(struct device *dev, struct isc_device *isc)
@@ -434,7 +460,7 @@ static int microchip_xisc_probe(struct platform_device *pdev)
 	}
 
 	isc->gamma_table = isc_sama7g5_gamma_table;
-	isc->gamma_max = 0;
+	isc->gamma_max = 2;
 
 	if (of_machine_is_compatible("microchip,sam9x7")) {
 		isc->max_width = ISC_SAM9X7_MAX_SUPPORT_WIDTH;

-- 
2.34.1

[PATCH v4 09/12] media: microchip-isc: add SAMA7G5 hue and saturation controls

[Balakrishnan Sambath]

SAMA7G5 extends CBC with hue and saturation. Add V4L2_CID_HUE and
V4L2_CID_SATURATION controls. Disable CBHS for RGB output since it
operates in YCbCr domain.

Co-developed-by: Balamanikandan Gunasundar <balamanikandan.gunasundar@microchip.com>
Signed-off-by: Balamanikandan Gunasundar <balamanikandan.gunasundar@microchip.com>
Signed-off-by: Balakrishnan Sambath <balakrishnan.s@microchip.com>
---
 .../media/platform/microchip/microchip-isc-base.c  | 87 +++++++++++++++++++++-
 .../media/platform/microchip/microchip-isc-regs.h  | 11 ++-
 drivers/media/platform/microchip/microchip-isc.h   |  5 +-
 .../platform/microchip/microchip-sama5d2-isc.c     |  2 +-
 .../platform/microchip/microchip-sama7g5-isc.c     |  8 +-
 5 files changed, 99 insertions(+), 14 deletions(-)

diff --git a/drivers/media/platform/microchip/microchip-isc-base.c b/drivers/media/platform/microchip/microchip-isc-base.c
index ae2a0c6ba566..1727c98665d1 100644
--- a/drivers/media/platform/microchip/microchip-isc-base.c
+++ b/drivers/media/platform/microchip/microchip-isc-base.c
@@ -810,7 +810,7 @@ static int isc_try_configure_pipeline(struct isc_device *isc)
 		if (ISC_IS_FORMAT_RAW(isc->try_config.sd_format->mbus_code)) {
 			isc->try_config.bits_pipeline = CFA_ENABLE |
 				CSC_ENABLE | GAM_ENABLES | WB_ENABLE |
-				SUB420_ENABLE | SUB422_ENABLE | CBC_ENABLE |
+				SUB420_ENABLE | SUB422_ENABLE | CBHS_ENABLE |
 				DPC_BLCENABLE;
 		} else {
 			isc->try_config.bits_pipeline = 0x0;
@@ -821,7 +821,7 @@ static int isc_try_configure_pipeline(struct isc_device *isc)
 		if (ISC_IS_FORMAT_RAW(isc->try_config.sd_format->mbus_code)) {
 			isc->try_config.bits_pipeline = CFA_ENABLE |
 				CSC_ENABLE | WB_ENABLE | GAM_ENABLES |
-				SUB422_ENABLE | CBC_ENABLE | DPC_BLCENABLE;
+				SUB422_ENABLE | CBHS_ENABLE | DPC_BLCENABLE;
 		} else {
 			isc->try_config.bits_pipeline = 0x0;
 		}
@@ -833,7 +833,7 @@ static int isc_try_configure_pipeline(struct isc_device *isc)
 		if (ISC_IS_FORMAT_RAW(isc->try_config.sd_format->mbus_code)) {
 			isc->try_config.bits_pipeline = CFA_ENABLE |
 				CSC_ENABLE | WB_ENABLE | GAM_ENABLES |
-				SUB422_ENABLE | CBC_ENABLE | DPC_BLCENABLE;
+				SUB422_ENABLE | CBHS_ENABLE | DPC_BLCENABLE;
 		} else {
 			isc->try_config.bits_pipeline = 0x0;
 		}
@@ -844,7 +844,7 @@ static int isc_try_configure_pipeline(struct isc_device *isc)
 		if (ISC_IS_FORMAT_RAW(isc->try_config.sd_format->mbus_code)) {
 			isc->try_config.bits_pipeline = CFA_ENABLE |
 				CSC_ENABLE | WB_ENABLE | GAM_ENABLES |
-				CBC_ENABLE | DPC_BLCENABLE;
+				CBHS_ENABLE | DPC_BLCENABLE;
 		} else {
 			isc->try_config.bits_pipeline = 0x0;
 		}
@@ -859,6 +859,56 @@ static int isc_try_configure_pipeline(struct isc_device *isc)
 	return 0;
 }
 
+static bool isc_format_has_chroma(u32 fourcc)
+{
+	switch (fourcc) {
+	case V4L2_PIX_FMT_YUV420:
+	case V4L2_PIX_FMT_YUV422P:
+	case V4L2_PIX_FMT_YUYV:
+	case V4L2_PIX_FMT_UYVY:
+	case V4L2_PIX_FMT_VYUY:
+		return true;
+	default:
+		return false;
+	}
+}
+
+/*
+ * isc_update_cbc_ctrl_activity() - Activate/deactivate CBC controls
+ *
+ * Called from isc_set_fmt(), isc_link_validate(), and isc_ctrl_init().
+ * At isc_ctrl_init() time isc->config.bits_pipeline is zero (no format
+ * has been negotiated yet), so all CBC controls are initially marked
+ * inactive.  They become active once a format that includes CBHS in the
+ * pipeline is configured via VIDIOC_S_FMT or link validation.
+ */
+static void isc_update_cbc_ctrl_activity(struct isc_device *isc)
+{
+	struct v4l2_ctrl_handler *hdl = &isc->ctrls.handler;
+	struct v4l2_ctrl *brightness;
+	struct v4l2_ctrl *contrast;
+	struct v4l2_ctrl *hue;
+	struct v4l2_ctrl *saturation;
+	bool cbc_active = isc->config.bits_pipeline & CBHS_ENABLE;
+	bool chroma_active = cbc_active && isc_format_has_chroma(isc->config.fourcc);
+
+	brightness = v4l2_ctrl_find(hdl, V4L2_CID_BRIGHTNESS);
+	if (brightness)
+		v4l2_ctrl_activate(brightness, cbc_active);
+
+	contrast = v4l2_ctrl_find(hdl, V4L2_CID_CONTRAST);
+	if (contrast)
+		v4l2_ctrl_activate(contrast, cbc_active);
+
+	hue = v4l2_ctrl_find(hdl, V4L2_CID_HUE);
+	if (hue)
+		v4l2_ctrl_activate(hue, chroma_active);
+
+	saturation = v4l2_ctrl_find(hdl, V4L2_CID_SATURATION);
+	if (saturation)
+		v4l2_ctrl_activate(saturation, chroma_active);
+}
+
 static int isc_try_fmt(struct isc_device *isc, struct v4l2_format *f)
 {
 	struct v4l2_pix_format *pixfmt = &f->fmt.pix;
@@ -902,6 +952,7 @@ static int isc_set_fmt(struct isc_device *isc, struct v4l2_format *f)
 	/* make the try configuration active */
 	isc->config = isc->try_config;
 	isc->fmt = isc->try_fmt;
+	isc_update_cbc_ctrl_activity(isc);
 
 	dev_dbg(isc->dev, "ISC set_fmt to %.4s @%dx%d\n",
 		(char *)&f->fmt.pix.pixelformat,
@@ -989,6 +1040,7 @@ static int isc_link_validate(struct media_link *link)
 		return ret;
 
 	isc->config = isc->try_config;
+	isc_update_cbc_ctrl_activity(isc);
 
 	dev_dbg(isc->dev, "New ISC configuration in place\n");
 
@@ -1446,6 +1498,7 @@ static int isc_s_ctrl(struct v4l2_ctrl *ctrl)
 	struct isc_device *isc = container_of(ctrl->handler,
 					     struct isc_device, ctrls.handler);
 	struct isc_ctrls *ctrls = &isc->ctrls;
+	struct regmap *regmap = isc->regmap;
 
 	if (ctrl->flags & V4L2_CTRL_FLAG_INACTIVE)
 		return 0;
@@ -1453,9 +1506,30 @@ static int isc_s_ctrl(struct v4l2_ctrl *ctrl)
 	switch (ctrl->id) {
 	case V4L2_CID_BRIGHTNESS:
 		ctrls->brightness = ctrl->val & ISC_CBC_BRIGHT_MASK;
+		regmap_write(regmap, ISC_CBC_BRIGHT + isc->offsets.cbc, ctrls->brightness);
 		break;
 	case V4L2_CID_CONTRAST:
 		ctrls->contrast = ctrl->val & ISC_CBC_CONTRAST_MASK;
+		regmap_write(regmap, ISC_CBC_CONTRAST + isc->offsets.cbc, ctrls->contrast);
+		break;
+	case V4L2_CID_HUE:
+		if (isc->has_cbhs) {
+			ctrls->hue = ctrl->val & ISC_CBHS_HUE_MASK;
+			regmap_write(regmap, ISC_CBHS_HUE, ctrls->hue);
+		}
+		break;
+	case V4L2_CID_SATURATION:
+		if (isc->has_cbhs) {
+			/*
+			 * The ISC CBHS SAT register holds a Q4 fixed-point
+			 * coefficient: 0 = grayscale, 16 = 1.0 (no change),
+			 * values above 16 boost saturation.  The V4L2 range
+			 * 0-100 (default 16) maps directly to this hardware
+			 * value; no unit conversion is applied.
+			 */
+			ctrls->saturation = ctrl->val & ISC_CBHS_SAT_MASK;
+			regmap_write(regmap, ISC_CBHS_SAT, ctrls->saturation);
+		}
 		break;
 	case V4L2_CID_GAMMA:
 		ctrls->gamma_index = ctrl->val;
@@ -1647,6 +1721,10 @@ static int isc_ctrl_init(struct isc_device *isc)
 	ctrls->brightness = 0;
 
 	v4l2_ctrl_new_std(hdl, ops, V4L2_CID_BRIGHTNESS, -1024, 1023, 1, 0);
+	if (isc->has_cbhs) {
+		v4l2_ctrl_new_std(hdl, ops, V4L2_CID_HUE, -180, 180, 1, 0);
+		v4l2_ctrl_new_std(hdl, ops, V4L2_CID_SATURATION, 0, 100, 1, 16);
+	}
 	v4l2_ctrl_new_std(hdl, ops, V4L2_CID_GAMMA, 0, isc->gamma_max, 1, 1);
 	isc->awb_ctrl = v4l2_ctrl_new_std(hdl, &isc_awb_ops,
 					  V4L2_CID_AUTO_WHITE_BALANCE,
@@ -1664,6 +1742,7 @@ static int isc_ctrl_init(struct isc_device *isc)
 	}
 
 	v4l2_ctrl_activate(isc->do_wb_ctrl, false);
+	isc_update_cbc_ctrl_activity(isc);
 
 	isc->r_gain_ctrl = v4l2_ctrl_new_custom(hdl, &isc_r_gain_ctrl, NULL);
 	isc->b_gain_ctrl = v4l2_ctrl_new_custom(hdl, &isc_b_gain_ctrl, NULL);
diff --git a/drivers/media/platform/microchip/microchip-isc-regs.h b/drivers/media/platform/microchip/microchip-isc-regs.h
index e77e1d9a1db8..2fd8916abf21 100644
--- a/drivers/media/platform/microchip/microchip-isc-regs.h
+++ b/drivers/media/platform/microchip/microchip-isc-regs.h
@@ -268,10 +268,13 @@
 #define ISC_CBC_CONTRAST	0x000003c0
 #define ISC_CBC_CONTRAST_MASK	GENMASK(11, 0)
 
-/* Hue Register */
-#define ISC_CBCHS_HUE	0x4e0
-/* Saturation Register */
-#define ISC_CBCHS_SAT	0x4e4
+/* Hue Register: signed 9-bit two's complement, covers -180 to +180 degrees */
+#define ISC_CBHS_HUE		0x4e0
+#define ISC_CBHS_HUE_MASK	GENMASK(8, 0)
+
+/* Saturation Register: unsigned Q4 fixed-point (1.0 = 16, V4L2 range 0-100) */
+#define ISC_CBHS_SAT		0x4e4
+#define ISC_CBHS_SAT_MASK	GENMASK(6, 0)
 
 /* Offset for SUB422 register specific to sama5d2 product */
 #define ISC_SAMA5D2_SUB422_OFFSET	0
diff --git a/drivers/media/platform/microchip/microchip-isc.h b/drivers/media/platform/microchip/microchip-isc.h
index ad4e98a1dd8f..2c8bcaaa26ea 100644
--- a/drivers/media/platform/microchip/microchip-isc.h
+++ b/drivers/media/platform/microchip/microchip-isc.h
@@ -88,7 +88,7 @@ struct isc_format {
 #define GAM_RENABLE	BIT(9)
 #define VHXS_ENABLE	BIT(10)
 #define CSC_ENABLE	BIT(11)
-#define CBC_ENABLE	BIT(12)
+#define CBHS_ENABLE	BIT(12)
 #define SUB422_ENABLE	BIT(13)
 #define SUB420_ENABLE	BIT(14)
 
@@ -139,6 +139,8 @@ struct isc_ctrls {
 
 	u32 brightness;
 	u32 contrast;
+	u32 hue;
+	u32 saturation;
 	u8 gamma_index;
 #define ISC_WB_NONE	0
 #define ISC_WB_AUTO	1
@@ -342,6 +344,7 @@ struct isc_device {
 	/* pointer to the defined gamma table */
 	const u32	(*gamma_table)[GAMMA_ENTRIES];
 	u32		gamma_max;
+	bool		has_cbhs;
 
 	u32		max_width;
 	u32		max_height;
diff --git a/drivers/media/platform/microchip/microchip-sama5d2-isc.c b/drivers/media/platform/microchip/microchip-sama5d2-isc.c
index 66d3d7891991..239aac170472 100644
--- a/drivers/media/platform/microchip/microchip-sama5d2-isc.c
+++ b/drivers/media/platform/microchip/microchip-sama5d2-isc.c
@@ -54,7 +54,7 @@
 
 #define ISC_SAMA5D2_PIPELINE \
 	(WB_ENABLE | CFA_ENABLE | CC_ENABLE | GAM_ENABLES | CSC_ENABLE | \
-	CBC_ENABLE | SUB422_ENABLE | SUB420_ENABLE)
+	CBHS_ENABLE | SUB422_ENABLE | SUB420_ENABLE)
 
 /* This is a list of the formats that the ISC can *output* */
 static const struct isc_format sama5d2_controller_formats[] = {
diff --git a/drivers/media/platform/microchip/microchip-sama7g5-isc.c b/drivers/media/platform/microchip/microchip-sama7g5-isc.c
index 8b73b625d92b..6705011edc2a 100644
--- a/drivers/media/platform/microchip/microchip-sama7g5-isc.c
+++ b/drivers/media/platform/microchip/microchip-sama7g5-isc.c
@@ -61,7 +61,7 @@
 #define ISC_SAMA7G5_PIPELINE \
 	(DPC_DPCENABLE | DPC_GDCENABLE | DPC_BLCENABLE | \
 	WB_ENABLE | CFA_ENABLE | CC_ENABLE | GAM_ENABLES | CSC_ENABLE | \
-	CBC_ENABLE | SUB422_ENABLE | SUB420_ENABLE)
+	CBHS_ENABLE | SUB422_ENABLE | SUB420_ENABLE)
 
 /* This is a list of the formats that the ISC can *output* */
 static const struct isc_format sama7g5_controller_formats[] = {
@@ -257,9 +257,8 @@ static void isc_sama7g5_config_cbc(struct isc_device *isc)
 	/* Configure what is set via v4l2 ctrls */
 	regmap_write(regmap, ISC_CBC_BRIGHT + isc->offsets.cbc, isc->ctrls.brightness);
 	regmap_write(regmap, ISC_CBC_CONTRAST + isc->offsets.cbc, isc->ctrls.contrast);
-	/* Configure Hue and Saturation as neutral midpoint */
-	regmap_write(regmap, ISC_CBCHS_HUE, 0);
-	regmap_write(regmap, ISC_CBCHS_SAT, (1 << 4));
+	regmap_write(regmap, ISC_CBHS_HUE, isc->ctrls.hue);
+	regmap_write(regmap, ISC_CBHS_SAT, isc->ctrls.saturation);
 }
 
 static void isc_sama7g5_config_cc(struct isc_device *isc)
@@ -461,6 +460,7 @@ static int microchip_xisc_probe(struct platform_device *pdev)
 
 	isc->gamma_table = isc_sama7g5_gamma_table;
 	isc->gamma_max = 2;
+	isc->has_cbhs = true;
 
 	if (of_machine_is_compatible("microchip,sam9x7")) {
 		isc->max_width = ISC_SAM9X7_MAX_SUPPORT_WIDTH;

-- 
2.34.1

[PATCH v4 10/12] media: microchip-isc: use weighted averages for Grey World AWB

[Balakrishnan Sambath]

Replace pixel counts with intensity-weighted averages. Add 2% outlier
rejection at histogram tails.

Signed-off-by: Balakrishnan Sambath <balakrishnan.s@microchip.com>
---
 .../media/platform/microchip/microchip-isc-base.c  | 167 +++++++++++++++------
 drivers/media/platform/microchip/microchip-isc.h   |   2 +
 2 files changed, 125 insertions(+), 44 deletions(-)

diff --git a/drivers/media/platform/microchip/microchip-isc-base.c b/drivers/media/platform/microchip/microchip-isc-base.c
index 1727c98665d1..67c2999ae5b5 100644
--- a/drivers/media/platform/microchip/microchip-isc-base.c
+++ b/drivers/media/platform/microchip/microchip-isc-base.c
@@ -39,6 +39,12 @@
 	(((mbus_code) == MEDIA_BUS_FMT_Y10_1X10) | \
 	(((mbus_code) == MEDIA_BUS_FMT_Y8_1X8)))
 
+/* 4.0 in Q9 fixed-point: cap grey-world correction at 4x. */
+#define ISC_AWB_GW_GAIN_MAX	(4u << 9)
+
+/* Outlier rejection: skip darkest/brightest 2% of histogram. */
+#define ISC_AWB_OUTLIER_DIV	50
+
 static inline void isc_update_v4l2_ctrls(struct isc_device *isc)
 {
 	struct isc_ctrls *ctrls = &isc->ctrls;
@@ -1286,6 +1292,11 @@ static void isc_hist_count(struct isc_device *isc, u32 *min, u32 *max)
 	u32 *hist_count = &ctrls->hist_count[ctrls->hist_id];
 	u32 *hist_entry = &ctrls->hist_entry[0];
 	u32 i;
+	u32 total_pixels;
+	u32 dark_threshold, bright_threshold;
+	u32 cumulative;
+	u64 weighted_sum;
+	u32 pixel_count;
 
 	*min = 0;
 	*max = HIST_ENTRIES;
@@ -1293,44 +1304,103 @@ static void isc_hist_count(struct isc_device *isc, u32 *min, u32 *max)
 	regmap_bulk_read(regmap, ISC_HIS_ENTRY + isc->offsets.his_entry,
 			 hist_entry, HIST_ENTRIES);
 
-	*hist_count = 0;
-	/*
-	 * we deliberately ignore the end of the histogram,
-	 * the most white pixels
-	 */
+	/* Calculate total pixels */
+	total_pixels = 0;
+	for (i = 0; i < HIST_ENTRIES; i++)
+		total_pixels += hist_entry[i];
+
+	/* Handle empty histogram case */
+	if (total_pixels == 0) {
+		*hist_count = 0;
+		ctrls->channel_avg[ctrls->hist_id] = 256; /* Default middle value */
+		ctrls->total_pixels[ctrls->hist_id] = 0;
+		*min = 1;
+		*max = HIST_ENTRIES - 1;
+		dev_dbg(isc->dev,
+			"isc wb: no pixels in histogram for channel %u\n",
+			ctrls->hist_id);
+		return;
+	}
+
+	/* Outlier rejection: skip darkest/brightest 2% of histogram */
+	dark_threshold = total_pixels / ISC_AWB_OUTLIER_DIV;
+	bright_threshold = total_pixels / ISC_AWB_OUTLIER_DIV;
+	cumulative = 0;
+
+	/* Find effective minimum (skip dark noise) */
+	*min = 1;
 	for (i = 1; i < HIST_ENTRIES; i++) {
-		if (*hist_entry && !*min)
+		cumulative += hist_entry[i];
+		if (cumulative > dark_threshold) {
 			*min = i;
-		if (*hist_entry)
+			break;
+		}
+	}
+
+	/* Find effective maximum (skip bright saturation) */
+	cumulative = 0;
+	*max = HIST_ENTRIES - 1;
+	for (i = HIST_ENTRIES - 1; i > *min; i--) {
+		cumulative += hist_entry[i];
+		if (cumulative > bright_threshold) {
 			*max = i;
-		*hist_count += i * (*hist_entry++);
+			break;
+		}
 	}
 
+	/* Ensure reasonable range */
+	if (*max <= *min) {
+		*min = HIST_ENTRIES / 4;
+		*max = (HIST_ENTRIES * 3) / 4;
+	}
+
+	/* Calculate both pixel count and weighted average for useful range */
+	*hist_count = 0;
+	weighted_sum = 0;
+
+	for (i = *min; i <= *max; i++) {
+		pixel_count = hist_entry[i];
+		*hist_count += pixel_count;
+		weighted_sum += (u64)i * pixel_count;
+	}
+
+	/* Store total useful pixels for this channel */
+	ctrls->total_pixels[ctrls->hist_id] = *hist_count;
+
+	/* Calculate channel average */
+	if (*hist_count > 0)
+		ctrls->channel_avg[ctrls->hist_id] =
+			div64_u64(weighted_sum, *hist_count);
+	else
+		/* Default middle value */
+		ctrls->channel_avg[ctrls->hist_id] = 256;
+
 	if (!*min)
 		*min = 1;
 
-	dev_dbg(isc->dev, "isc wb: hist_id %u, hist_count %u",
-		ctrls->hist_id, *hist_count);
+	dev_dbg(isc->dev,
+		"isc wb: hist_id %u, avg %u, count %u, range [%u,%u], total %u\n",
+		ctrls->hist_id, ctrls->channel_avg[ctrls->hist_id],
+		*hist_count, *min, *max, total_pixels);
 }
 
 static void isc_wb_update(struct isc_ctrls *ctrls)
 {
 	struct isc_device *isc = container_of(ctrls, struct isc_device, ctrls);
-	u32 *hist_count = &ctrls->hist_count[0];
 	u32 c, offset[4];
 	u64 avg = 0;
-	/* We compute two gains, stretch gain and grey world gain */
-	u32 s_gain[4], gw_gain[4];
+	u32 gain, gw_gain, s_gain;
+	u32 min_pixels;
+	u32 frame_pixels;
 
 	/*
 	 * According to Grey World, we need to set gains for R/B to normalize
 	 * them towards the green channel.
-	 * Thus we want to keep Green as fixed and adjust only Red/Blue
-	 * Compute the average of the both green channels first
+	 * Thus we want to keep Green as fixed and adjust only Red/Blue.
+	 * Compute the average of the both green channels first.
 	 */
-	avg = (u64)hist_count[ISC_HIS_CFG_MODE_GR] +
-		(u64)hist_count[ISC_HIS_CFG_MODE_GB];
-	avg >>= 1;
+	avg = (ctrls->channel_avg[ISC_HIS_CFG_MODE_GR] +
+		ctrls->channel_avg[ISC_HIS_CFG_MODE_GB]) >> 1;
 
 	dev_dbg(isc->dev, "isc wb: green components average %llu\n", avg);
 
@@ -1338,7 +1408,23 @@ static void isc_wb_update(struct isc_ctrls *ctrls)
 	if (!avg)
 		return;
 
+	/*
+	 * Require a minimum pixel count for both black-level offset and
+	 * grey-world gain: 1/64 of the frame area, which equals ~6.25% of
+	 * one Bayer channel's expected pixel count.  This scales with sensor
+	 * resolution and prevents noise-dominated histograms (from very small
+	 * crops or a nearly-empty frame) from producing wild corrections.
+	 * A floor of 64 ensures the guard is non-zero for tiny crops.
+	 */
+	frame_pixels = isc->fmt.fmt.pix.width * isc->fmt.fmt.pix.height;
+	min_pixels = frame_pixels ? max(frame_pixels >> 6, 64u) : 64u;
+
 	for (c = ISC_HIS_CFG_MODE_GR; c <= ISC_HIS_CFG_MODE_B; c++) {
+		u32 hist_min = ctrls->hist_minmax[c][HIST_MIN_INDEX];
+		u32 hist_max = ctrls->hist_minmax[c][HIST_MAX_INDEX];
+		u32 channel_avg = ctrls->channel_avg[c];
+		u32 total_pixels = ctrls->total_pixels[c];
+
 		/*
 		 * the color offset is the minimum value of the histogram.
 		 * we stretch this color to the full range by substracting
@@ -1364,40 +1450,33 @@ static void isc_wb_update(struct isc_ctrls *ctrls)
 		ctrls->offset[c] = -ctrls->offset[c];
 
 		/*
-		 * the stretch gain is the total number of histogram bins
-		 * divided by the actual range of color component (Max - Min)
-		 * If we compute gain like this, the actual color component
-		 * will be stretched to the full histogram.
-		 * We need to shift 9 bits for precision, we have 9 bits for
-		 * decimals
+		 * Stretch gain: scale the histogram range [hist_min, hist_max]
+		 * to the full 512-bin span.  Result is in Q9 fixed-point
+		 * (1.0 = 512).
 		 */
-		s_gain[c] = (HIST_ENTRIES << 9) /
-			(ctrls->hist_minmax[c][HIST_MAX_INDEX] -
-			ctrls->hist_minmax[c][HIST_MIN_INDEX] + 1);
+		s_gain = (HIST_ENTRIES << 9) / (hist_max - hist_min + 1);
 
 		/*
-		 * Now we have to compute the gain w.r.t. the average.
-		 * Add/lose gain to the component towards the average.
-		 * If it happens that the component is zero, use the
-		 * fixed point value : 1.0 gain.
+		 * Grey-world gain: scale each channel towards the green
+		 * average.  Require a minimum pixel count so noise-dominated
+		 * channels do not produce wild corrections.
 		 */
-		if (hist_count[c])
-			gw_gain[c] = div_u64(avg << 9, hist_count[c]);
+		if (channel_avg > 0 && total_pixels >= min_pixels)
+			gw_gain = div64_u64((avg << 9), channel_avg);
 		else
-			gw_gain[c] = 1 << 9;
+			gw_gain = 1 << 9;
 
-		dev_dbg(isc->dev,
-			"isc wb: component %d, s_gain %u, gw_gain %u\n",
-			c, s_gain[c], gw_gain[c]);
-		/* multiply both gains and adjust for decimals */
-		ctrls->gain[c] = s_gain[c] * gw_gain[c];
-		ctrls->gain[c] >>= 9;
+		/* Cap grey-world correction at 4x to avoid over-amplification. */
+		gw_gain = min_t(u32, gw_gain, ISC_AWB_GW_GAIN_MAX);
 
-		/* make sure we are not out of range */
-		ctrls->gain[c] = clamp_val(ctrls->gain[c], 0, GENMASK(12, 0));
+		/* Combine stretch and grey-world gains; result stays in Q9. */
+		gain = (s_gain * gw_gain) >> 9;
 
-		dev_dbg(isc->dev, "isc wb: component %d, final gain %u\n",
-			c, ctrls->gain[c]);
+		ctrls->gain[c] = clamp_val(gain, 0, GENMASK(12, 0));
+
+		dev_dbg(isc->dev,
+			"isc wb: c=%u black=%u avg=%u s_gain=%u gw_gain=%u gain=%u",
+			c, hist_min, channel_avg, s_gain, gw_gain, gain);
 	}
 }
 
diff --git a/drivers/media/platform/microchip/microchip-isc.h b/drivers/media/platform/microchip/microchip-isc.h
index 2c8bcaaa26ea..fccd7ff4846b 100644
--- a/drivers/media/platform/microchip/microchip-isc.h
+++ b/drivers/media/platform/microchip/microchip-isc.h
@@ -158,6 +158,8 @@ struct isc_ctrls {
 #define HIST_MIN_INDEX		0
 #define HIST_MAX_INDEX		1
 	u32 hist_minmax[HIST_BAYER][2];
+	u32 channel_avg[HIST_BAYER];
+	u32 total_pixels[HIST_BAYER];
 };
 
 #define ISC_PIPE_LINE_NODE_NUM	15

-- 
2.34.1

[PATCH v4 11/12] media: microchip-isc: smooth AWB gains with EMA filter

[Balakrishnan Sambath]

Apply exponential moving average (alpha=0.25) to reduce per-frame
flicker from sensor noise.

Signed-off-by: Balakrishnan Sambath <balakrishnan.s@microchip.com>
---
 drivers/media/platform/microchip/microchip-isc-base.c | 19 ++++++++++++++++---
 drivers/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/drivers/media/platform/microchip/microchip-isc-base.c
index 67c2999ae5b5..82eff6012527 100644
--- a/drivers/media/platform/microchip/microchip-isc-base.c
+++ b/drivers/media/platform/microchip/microchip-isc-base.c
@@ -93,6 +93,7 @@ static inline void isc_reset_awb_ctrls(struct isc_device *isc)
 	for (c = ISC_HIS_CFG_MODE_GR; c <= ISC_HIS_CFG_MODE_B; c++) {
 		/* gains have a fixed point at 9 decimals */
 		isc->ctrls.gain[c] = 1 << 9;
+		isc->ctrls.gain_smooth[c] = 1 << 9;
 		/* offsets are in 2's complements */
 		isc->ctrls.offset[c] = 0;
 	}
@@ -1472,11 +1473,23 @@ static void isc_wb_update(struct isc_ctrls *ctrls)
 		/* Combine stretch and grey-world gains; result stays in Q9. */
 		gain = (s_gain * gw_gain) >> 9;
 
-		ctrls->gain[c] = clamp_val(gain, 0, GENMASK(12, 0));
+		/*
+		 * Smooth gain updates with an exponential weighted average
+		 * to suppress per-frame flicker:
+		 *   smooth[n] = (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] = (3 * ctrls->gain_smooth[c] + gain) / 4;
+		ctrls->gain_smooth[c] = min_t(u32, ctrls->gain_smooth[c],
+					      GENMASK(12, 0));
+
+		ctrls->gain[c] = ctrls->gain_smooth[c];
 
 		dev_dbg(isc->dev,
-			"isc wb: c=%u black=%u avg=%u s_gain=%u gw_gain=%u gain=%u",
-			c, hist_min, channel_avg, s_gain, gw_gain, gain);
+			"isc wb: c=%u black=%u avg=%u s_gain=%u gw_gain=%u gain=%u smooth=%u\n",
+			c, hist_min, channel_avg, s_gain, gw_gain, gain,
+			ctrls->gain_smooth[c]);
 	}
 }
 
diff --git a/drivers/media/platform/microchip/microchip-isc.h b/drivers/media/platform/microchip/microchip-isc.h
index fccd7ff4846b..4503fcbfdce8 100644
--- a/drivers/media/platform/microchip/microchip-isc.h
+++ b/drivers/media/platform/microchip/microchip-isc.h
@@ -149,6 +149,7 @@ struct isc_ctrls {
 
 	/* one for each component : GR, R, GB, B */
 	u32 gain[HIST_BAYER];
+	u32 gain_smooth[HIST_BAYER];
 	s32 offset[HIST_BAYER];
 
 	u32 hist_entry[HIST_ENTRIES];

-- 
2.34.1

[PATCH v4 12/12] media: microchip-isc: scale DPC black level to sensor bit depth

[Balakrishnan Sambath]

Scale the nominal 10-bit black level (64 counts) to match 8/10/12-bit
sensor bus width.

Signed-off-by: Balakrishnan Sambath <balakrishnan.s@microchip.com>
---
 .../media/platform/microchip/microchip-sama7g5-isc.c  | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/drivers/media/platform/microchip/microchip-sama7g5-isc.c b/drivers/media/platform/microchip/microchip-sama7g5-isc.c
index 6705011edc2a..d978466aa489 100644
--- a/drivers/media/platform/microchip/microchip-sama7g5-isc.c
+++ b/drivers/media/platform/microchip/microchip-sama7g5-isc.c
@@ -26,6 +26,7 @@
  * HIS: Histogram module performs statistic counters on the frames
  */
 
+#include <linux/bitfield.h>
 #include <linux/clk.h>
 #include <linux/clkdev.h>
 #include <linux/clk-provider.h>
@@ -289,9 +290,25 @@ static void isc_sama7g5_config_dpc(struct isc_device *isc)
 {
 	u32 bay_cfg = isc->config.sd_format->cfa_baycfg;
 	struct regmap *regmap = isc->regmap;
+	u32 bps, bloff;
+
+	/*
+	 * Scale the nominal 10-bit black level offset (64 counts) to the
+	 * actual sensor bus width.
+	 * ISC_PFE_CFG0_BPS encodes (12 - bit_depth) / 2 in bits[30:28]:
+	 *   BPS_EIGHT  = 4  ->  8-bit  -> bloff = 64 >> 2 = 16
+	 *   BPS_TEN    = 2  -> 10-bit  -> bloff = 64
+	 *   BPS_TWELVE = 0  -> 12-bit  -> bloff = min(64 << 2, 255) = 255
+	 * The BLOFF hardware field is 8-bit so values are clamped to 255.
+	 */
+	bps = FIELD_GET(ISC_PFE_CFG0_BPS_MASK, isc->config.sd_format->pfe_cfg0_bps);
+	if (bps >= 2)
+		bloff = 64u >> (bps - 2);
+	else
+		bloff = min(64u << (2 - bps), 255u);
 
 	regmap_update_bits(regmap, ISC_DPC_CFG, ISC_DPC_CFG_BLOFF_MASK,
-			   (64 << ISC_DPC_CFG_BLOFF_SHIFT));
+			   (bloff << ISC_DPC_CFG_BLOFF_SHIFT));
 	regmap_update_bits(regmap, ISC_DPC_CFG, ISC_DPC_CFG_BAYCFG_MASK,
 			   (bay_cfg << ISC_DPC_CFG_BAYCFG_SHIFT));
 }

-- 
2.34.1

Re: [PATCH v4 04/12] media: microchip-isc: fix PM runtime leak in AWB work handler

[Eugen Hristev]

On 5/18/26 14:29, Balakrishnan Sambath wrote:
> Early return when streaming stops skips pm_runtime_put_sync(),
> leaking the reference and preventing runtime suspend.
> 
> Fixes: 91b4e487b0c6 ("media: microchip: add ISC driver as Microchip ISC")
> Cc: stable@vger.kernel.org
> Signed-off-by: Balakrishnan Sambath <balakrishnan.s@microchip.com>
> ---

Reviewed-by: Eugen Hristev <ehristev@kernel.org>

Re: [PATCH v4 01/12] media: microchip-isc: fix SBGGR10 Bayer pattern

[Eugen Hristev]

On 5/18/26 14:29, Balakrishnan Sambath wrote:
> SBGGR10 was mapped to ISC_BAY_CFG_RGRG instead of ISC_BAY_CFG_BGBG,
> causing red/blue channel swap.
> 
> Fixes: 91b4e487b0c6 ("media: microchip: add ISC driver as Microchip ISC")
> Cc: stable@vger.kernel.org
> Signed-off-by: Balakrishnan Sambath <balakrishnan.s@microchip.com>
> ---

Reviewed-by: Eugen Hristev <ehristev@kernel.org>