From 5c6b7b60d7d607b59b4208e758180d4f93be8788 Mon Sep 17 00:00:00 2001 From: Dave Stevenson 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 --- 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; }