[PATCH 2/2] media: i2c: ov5645: Add a small delay after writes in ov5645_set_register_array()

From: Biju Das <biju.das.jz@bp.renesas.com>
To: Sakari Ailus <sakari.ailus@linux.intel.com>,
	Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: Biju Das <biju.das.jz@bp.renesas.com>,
	linux-media@vger.kernel.org,
	Geert Uytterhoeven <geert+renesas@glider.be>,
	Prabhakar Mahadev Lad <prabhakar.mahadev-lad.rj@bp.renesas.com>,
	Biju Das <biju.das.au@gmail.com>,
	linux-renesas-soc@vger.kernel.org
Subject: [PATCH 2/2] media: i2c: ov5645: Add a small delay after writes in ov5645_set_register_array()
Date: Tue, 13 Feb 2024 14:02:40 +0000	[thread overview]
Message-ID: <20240213140240.159057-3-biju.das.jz@bp.renesas.com> (raw)
In-Reply-To: <20240213140240.159057-1-biju.das.jz@bp.renesas.com>

Since OV5645 is showing issues @400kHz, it makes sense to add a small
delay after register writes for settling the register values. So introduce
a small delay by adding a read() after write() and also add a debug code
for data mismatch.

Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
---
 drivers/media/i2c/ov5645.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/media/i2c/ov5645.c b/drivers/media/i2c/ov5645.c
index a5cc959d535e..ea9b7c610f2d 100644
--- a/drivers/media/i2c/ov5645.c
+++ b/drivers/media/i2c/ov5645.c
@@ -624,11 +624,20 @@ static int ov5645_set_register_array(struct ov5645 *ov5645,
 {
 	unsigned int i;
 	int ret;
+	u8 val;
 
 	for (i = 0; i < num_settings; ++i, ++settings) {
 		ret = ov5645_write_reg(ov5645, settings->reg, settings->val);
 		if (ret < 0)
 			return ret;
+
+		ret = ov5645_read_reg(ov5645, settings->reg, &val);
+		if (ret < 0)
+			return ret;
+
+		if (val != settings->val)
+			dev_dbg(ov5645->dev, "Data mismatch reg=%x val=%x/%x\n",
+				settings->reg, settings->val, val);
 	}
 
 	return 0;
-- 
2.25.1

