[PATCH v6 05/12] media: rppx1: Add support for Auto Exposure Measurement

["Niklas Söderlund" <niklas.soderlund+renesas@ragnatech.se>]

Extend the RPPX1 driver to allow setting the EXM configuration using the
RkISP1 parameter buffer format. It uses the RPPX1 framework for
parameters and its writer abstraction to allow the user to control how
(and when) configuration is applied to the RPPX1.

As the RkISP1 parameters buffer have lower precision then the RPPX1
hardware the values needs to be scaled. The behavior matches the RkISP1
hardware.

Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Tested-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
---
 .../platform/dreamchip/rppx1/rpp_params.c     |  4 +
 .../platform/dreamchip/rppx1/rpp_stats.c      |  4 +
 .../platform/dreamchip/rppx1/rppx1_exm.c      | 89 +++++++++++++++++++
 3 files changed, 97 insertions(+)

diff --git a/drivers/media/platform/dreamchip/rppx1/rpp_params.c b/drivers/media/platform/dreamchip/rppx1/rpp_params.c
index 92f16e139ee4..e3f96528b837 100644
--- a/drivers/media/platform/dreamchip/rppx1/rpp_params.c
+++ b/drivers/media/platform/dreamchip/rppx1/rpp_params.c
@@ -18,6 +18,7 @@ static const struct v4l2_isp_params_block_type_info
 rkisp1_ext_params_blocks_info[] = {
 	RKISP1_PARAMS_BLOCK_INFO(AWB_GAIN, awb_gain),
 	RKISP1_PARAMS_BLOCK_INFO(AWB_MEAS, awb_meas),
+	RKISP1_PARAMS_BLOCK_INFO(AEC_MEAS, aec),
 };
 
 int rppx1_params(struct rppx1 *rpp, struct vb2_buffer *vb, size_t max_size,
@@ -58,6 +59,9 @@ int rppx1_params(struct rppx1 *rpp, struct vb2_buffer *vb, size_t max_size,
 		case RKISP1_EXT_PARAMS_BLOCK_TYPE_AWB_MEAS:
 			module = &rpp->post.wbmeas;
 			break;
+		case RKISP1_EXT_PARAMS_BLOCK_TYPE_AEC_MEAS:
+			module = &rpp->pre1.exm;
+			break;
 		default:
 			module = NULL;
 			break;
diff --git a/drivers/media/platform/dreamchip/rppx1/rpp_stats.c b/drivers/media/platform/dreamchip/rppx1/rpp_stats.c
index a6abb85f0df1..d62b26e24cb0 100644
--- a/drivers/media/platform/dreamchip/rppx1/rpp_stats.c
+++ b/drivers/media/platform/dreamchip/rppx1/rpp_stats.c
@@ -15,5 +15,9 @@ void rppx1_stats_fill_isr(struct rppx1 *rpp, u32 isc, void *buf)
 	if (isc & RPPX1_IRQ_ID_POST_AWB_MEAS)
 		if (!rpp_module_call(&rpp->post.wbmeas, stats_rkisp1, &stats->params))
 			stats->meas_type |= RKISP1_CIF_ISP_STAT_AWB;
+
+	if (isc & RPPX1_IRQ_ID_PRE1_EXM)
+		if (!rpp_module_call(&rpp->pre1.exm, stats_rkisp1, &stats->params))
+			stats->meas_type |= RKISP1_CIF_ISP_STAT_AUTOEXP;
 }
 EXPORT_SYMBOL_GPL(rppx1_stats_fill_isr);
diff --git a/drivers/media/platform/dreamchip/rppx1/rppx1_exm.c b/drivers/media/platform/dreamchip/rppx1/rppx1_exm.c
index 0c40300e13ad..c9478ea5f851 100644
--- a/drivers/media/platform/dreamchip/rppx1/rppx1_exm.c
+++ b/drivers/media/platform/dreamchip/rppx1/rppx1_exm.c
@@ -10,6 +10,7 @@
 #define EXM_START_REG			0x0004
 
 #define EXM_CTRL_REG			0x0008
+#define EXM_CTRL_EXM_AUTOSTOP		BIT(1) /* HW doc says not supported. */
 #define EXM_CTRL_EXM_UPDATE_ENABLE	BIT(0)
 
 #define EXM_MODE_REG			0x000c
@@ -46,6 +47,94 @@ static int rppx1_exm_probe(struct rpp_module *mod)
 	return 0;
 }
 
+static int
+rppx1_exm_param_rkisp1(struct rpp_module *mod,
+		       const union rppx1_params_rkisp1_config *block,
+		       rppx1_reg_write write, void *priv)
+{
+	const struct rkisp1_ext_params_aec_config *cfg = &block->aec;
+	const struct rkisp1_cif_isp_aec_config *arg = &cfg->config;
+	u32 h_offs, v_offs, h_size, v_size;
+
+	/* If the modules is disabled, simply bypass it. */
+	if (cfg->header.flags & RKISP1_EXT_PARAMS_FL_BLOCK_DISABLE) {
+		write(priv, mod->base + EXM_MODE_REG, 0);
+		return 0;
+	}
+
+	/* RGB bayer exposure measurement */
+	write(priv, mod->base + EXM_MODE_REG, 2);
+
+	write(priv, mod->base + EXM_CTRL_REG, EXM_CTRL_EXM_UPDATE_ENABLE |
+	      arg->autostop ? EXM_CTRL_EXM_AUTOSTOP : 0);
+
+	/*
+	 * Select where to sample.
+	 * 0 - after input acquisition
+	 * 1 - after black level subtraction
+	 * 2 - after input linearization
+	 * 3 - after lens shade correction
+	 * 4 - after white balance gain stage
+	 * 5 - after defect pixel correction
+	 * 6 - after denoising
+	 */
+	write(priv, mod->base + EXM_CHANNEL_SEL_REG, 6);
+
+	if (arg->mode == RKISP1_CIF_ISP_EXP_MEASURING_MODE_0) {
+		/* Coefficients for a BT.601 BAYER (from datasheet). */
+		write(priv, mod->base + EXM_COEFF_R_REG, 38);
+		write(priv, mod->base + EXM_COEFF_G_GR_REG, 75);
+		write(priv, mod->base + EXM_COEFF_B_REG, 15);
+		write(priv, mod->base + EXM_COEFF_GB_REG, 75);
+	} else {
+		/* Y = (R + Gr + B + Gb) / 4*/
+		write(priv, mod->base + EXM_COEFF_R_REG, 128);
+		write(priv, mod->base + EXM_COEFF_G_GR_REG, 128);
+		write(priv, mod->base + EXM_COEFF_B_REG, 128);
+		write(priv, mod->base + EXM_COEFF_GB_REG, 128);
+	}
+
+	/*
+	 * Adjust and set measurement window to hardware limitations,
+	 * - Offsets must be even.
+	 * - Width and height must be divisible by 10.
+	 */
+	h_offs = arg->meas_window.h_offs & 0x1ffe;
+	v_offs = arg->meas_window.v_offs & 0x1ffe;
+	h_size = (arg->meas_window.h_size - 1) - ((arg->meas_window.h_size - 1) % 10);
+	v_size = (arg->meas_window.v_size - 1) - ((arg->meas_window.v_size - 1) % 10);
+
+	write(priv, mod->base + EXM_H_OFFS_REG, h_offs);
+	write(priv, mod->base + EXM_V_OFFS_REG, v_offs);
+	write(priv, mod->base + EXM_H_SIZE_REG, h_size / 5);
+	write(priv, mod->base + EXM_V_SIZE_REG, v_size / 5);
+
+	/* Set last measurement line for ready interrupt. */
+	write(priv, mod->base + EXM_LAST_MEAS_LINE_REG, v_offs + v_size + 1);
+
+	write(priv, mod->base + EXM_START_REG, 1);
+
+	return 0;
+}
+
+static int rppx1_exm_stats_rkisp1(struct rpp_module *mod,
+				  struct rkisp1_cif_isp_stat *stats)
+{
+	u8 *meas = &stats->ae.exp_mean[0];
+	/*
+	 * The RkISP mean stats are 8-bit while the RPP can be 8 or 20 bit.
+	 * Figure out how much we need to adjust the output parameters.
+	 */
+	const unsigned int shift = mod->info.exm.resultbits - 8;
+
+	for (unsigned int i = 0; i < EXM_MEAN_REG_NUM; i++)
+		meas[i] = rpp_module_read(mod, EXM_MEAN_REG(i)) >> shift;
+
+	return 0;
+}
+
 const struct rpp_module_ops rppx1_exm_ops = {
 	.probe = rppx1_exm_probe,
+	.param_rkisp1 = rppx1_exm_param_rkisp1,
+	.stats_rkisp1 = rppx1_exm_stats_rkisp1,
 };
-- 
2.53.0