Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   Jacopo Mondi <jacopo+renesas@jmondi.org>
To:     kieran.bingham+renesas@ideasonboard.com,
        laurent.pinchart+renesas@ideasonboard.com,
        niklas.soderlund+renesas@ragnatech.se, geert@linux-m68k.org
Cc:     Jacopo Mondi <jacopo+renesas@jmondi.org>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        linux-media@vger.kernel.org, linux-renesas-soc@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: [PATCH v2 12/18] media: i2c: rdacm21: Give more time to OV490 to boot
Date:   Mon, 15 Mar 2021 14:15:06 +0100
Message-Id: <20210315131512.133720-13-jacopo+renesas@jmondi.org>
In-Reply-To: <20210315131512.133720-1-jacopo+renesas@jmondi.org>
References: <20210315131512.133720-1-jacopo+renesas@jmondi.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

It has been observed through repeated testing (250 boots) that in the
10% of the cases the RDACM21 initialization sequence errors out due a
timeout waiting for the OV490 firmware to complete its boot phase.

Albeit being the current timeout relatively large (300-600 milliseconds),
doubling it reduces the sporadic error rate down to 1 over an 80 boot
sequences test run.

The firmware boot delay is unfortunately not characterized in the camera
module manual.

Fixes: a59f853b3b4b ("media: i2c: Add driver for RDACM21 camera module")
Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
---
 drivers/media/i2c/rdacm21.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/media/i2c/rdacm21.c b/drivers/media/i2c/rdacm21.c
index 50a9b0d8255d..07cf077d8efd 100644
--- a/drivers/media/i2c/rdacm21.c
+++ b/drivers/media/i2c/rdacm21.c
@@ -53,7 +53,7 @@
 #define OV490_PID			0x8080300a
 #define OV490_VER			0x8080300b
 #define OV490_PID_TIMEOUT		20
-#define OV490_OUTPUT_EN_TIMEOUT		300
+#define OV490_OUTPUT_EN_TIMEOUT		600
 
 #define OV490_GPIO0			BIT(0)
 #define OV490_SPWDN0			BIT(0)
-- 
2.30.0