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From 5c6b7b60d7d607b59b4208e758180d4f93be8788 Mon Sep 17 00:00:00 2001
From: Dave Stevenson <dave.stevenson@raspberrypi.com>
Date: Mon, 6 Jul 2020 17:51:32 +0100
Subject: [PATCH] media: i2c: ov9281: Read chip ID via 2 reads
Vision Components have made an OV9281 module which blocks reading
back the majority of registers to comply with NDAs, and in doing
so doesn't allow auto-increment register reading as used when
reading the chip ID.
Use two reads and manually combine the results.
Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
---
drivers/media/i2c/ov9281.c | 14 +++++++++-----
1 file changed, 9 insertions(+), 5 deletions(-)
--- a/drivers/media/i2c/ov9281.c
+++ b/drivers/media/i2c/ov9281.c
@@ -904,13 +904,17 @@ static int ov9281_check_sensor_id(struct
struct i2c_client *client)
{
struct device *dev = &ov9281->client->dev;
- u32 id = 0;
+ u32 id = 0, id_msb;
int ret;
- ret = ov9281_read_reg(client, OV9281_REG_CHIP_ID,
- OV9281_REG_VALUE_16BIT, &id);
- if (id != CHIP_ID) {
- dev_err(dev, "Unexpected sensor id(%06x), ret(%d)\n", id, ret);
+ ret = ov9281_read_reg(client, OV9281_REG_CHIP_ID + 1,
+ OV9281_REG_VALUE_08BIT, &id);
+ if (!ret)
+ ret = ov9281_read_reg(client, OV9281_REG_CHIP_ID,
+ OV9281_REG_VALUE_08BIT, &id_msb);
+ id |= (id_msb << 8);
+ if (ret || id != CHIP_ID) {
+ dev_err(dev, "Unexpected sensor id(%04x), ret(%d)\n", id, ret);
return -ENODEV;
}
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