Commit 2e490139 authored Dec 21, 2015 by Grygorii Strashko Committed by Mauro Carvalho Chehab Jan 25, 2016

[media] media: i2c: ov2659: speedup probe if no device connected



The ov2659 driver performs device detection and initialization in the
following way:
 - send reset command REG_SOFTWARE_RESET
 - load array of predefined register's setting (~150 values)
 - read device version REG_SC_CHIP_ID_H/REG_SC_CHIP_ID_L
 - check version and exit if invalid.

As result, for not connected device there will be >~150 i2c transactions
executed before device version checking and exit (there are no
failures detected because ov2659 declared as I2C_CLIENT_SCCB and NACKs
are ignored in this case).

Let's fix that by checking the chip version first and start
initialization only if it's supported.

Cc: Benoit Parrot <bparrot@ti.com>
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Acked-by: Lad, Prabhakar <prabhakar.csengg@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

parent d5441ea5

drivers/media/i2c/ov2659.c

+3 −5

Original line number	Diff line number	Diff line
		@@ -1321,10 +1321,6 @@ static int ov2659_detect(struct v4l2_subdev *sd)
		}
		usleep_range(1000, 2000);

		ret = ov2659_init(sd, 0);
		if (ret < 0)
		return ret;

		/* Check sensor revision */
		ret = ov2659_read(client, REG_SC_CHIP_ID_H, &pid);
		if (!ret)
		@@ -1338,8 +1334,10 @@ static int ov2659_detect(struct v4l2_subdev *sd)
		dev_err(&client->dev,
		"Sensor detection failed (%04X, %d)\n",
		id, ret);
		else
		else {
		dev_info(&client->dev, "Found OV%04X sensor\n", id);
		ret = ov2659_init(sd, 0);
		}
		}

		return ret;