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From:   Moses Christopher Bollavarapu <mosescb.dev@gmail.com>
To:     mchehab@kernel.org, linux-media@vger.kernel.org,
        linux-kernel@vger.kernel.org
Cc:     Moses Christopher Bollavarapu <mosescb.dev@gmail.com>
Subject: [PATCH] media: ov7640: Use ARRAY_SIZE instead of manual checking
Date:   Thu, 17 Mar 2022 15:47:14 +0100
Message-Id: <20220317144714.47442-1-mosescb.dev@gmail.com>
MIME-Version: 1.0
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Currently, the driver ends the reg-val list with a 0xFF as a check to stop
the loop. Instead an array of reg-vals can be used to avoid this check,
by using the ARRAY_SIZE(arr) macro to obtain the length of the array and
iterate over it.

Signed-off-by: Moses Christopher Bollavarapu <mosescb.dev@gmail.com>
---
 drivers/media/i2c/ov7640.c | 33 +++++++++++++++++++--------------
 1 file changed, 19 insertions(+), 14 deletions(-)

diff --git a/drivers/media/i2c/ov7640.c b/drivers/media/i2c/ov7640.c
index 010803d58ce8..977cd2d8ad33 100644
--- a/drivers/media/i2c/ov7640.c
+++ b/drivers/media/i2c/ov7640.c
@@ -13,23 +13,28 @@
 MODULE_DESCRIPTION("OmniVision ov7640 sensor driver");
 MODULE_LICENSE("GPL v2");
 
-static const u8 initial_registers[] = {
-	0x12, 0x80,
-	0x12, 0x54,
-	0x14, 0x24,
-	0x15, 0x01,
-	0x28, 0x20,
-	0x75, 0x82,
-	0xFF, 0xFF, /* Terminator (reg 0xFF is unused) */
+struct reg_val {
+	u8 reg;
+	u8 val;
 };
 
-static int write_regs(struct i2c_client *client, const u8 *regs)
-{
-	int i;
+static const struct reg_val regval_init[] = {
+	{0x12, 0x80},
+	{0x12, 0x54},
+	{0x14, 0x24},
+	{0x15, 0x01},
+	{0x28, 0x20},
+	{0x75, 0x82},
+};
 
-	for (i = 0; regs[i] != 0xFF; i += 2)
-		if (i2c_smbus_write_byte_data(client, regs[i], regs[i + 1]) < 0)
+static int write_regs(struct i2c_client *client,
+		const struct reg_val *rv, int len)
+{
+	while (--len >= 0) {
+		if (i2c_smbus_write_byte_data(client, rv->reg, rv->val) < 0)
 			return -1;
+		rv++;
+	}
 	return 0;
 }
 
@@ -56,7 +61,7 @@ static int ov7640_probe(struct i2c_client *client,
 	v4l_info(client, "chip found @ 0x%02x (%s)\n",
 			client->addr << 1, client->adapter->name);
 
-	if (write_regs(client, initial_registers) < 0) {
+	if (write_regs(client, regval_init, ARRAY_SIZE(regval_init)) < 0) {
 		v4l_err(client, "error initializing OV7640\n");
 		return -ENODEV;
 	}
-- 
2.30.2