From: Kieran Bingham <kieran.bingham@xxxxxxxxxxxxxxxx> The camera's power regulator is connected to a GPIO on the max9286. Unfortunately this causes us a circular dependency on the regulator needing the gpio_chip before the max9286 has probed. Until we can get the regulator framework to create the regulator device on demand (at the time of regulator_get(), the gpio_chip is available) we need to force the gpio line with a gpio-hog, and handle the delay required with a manual sleep. This is specific to the Eagle-V3M. Signed-off-by: Kieran Bingham <kieran.bingham@xxxxxxxxxxxxxxxx> --- drivers/media/i2c/max9286.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/drivers/media/i2c/max9286.c b/drivers/media/i2c/max9286.c index 057258a3c645..090b6c0f81e9 100644 --- a/drivers/media/i2c/max9286.c +++ b/drivers/media/i2c/max9286.c @@ -964,6 +964,20 @@ static int max9286_init(struct device *dev) return ret; } + /* + * Regulator Workaround: + * + * We must sleep at least 8 seconds to let the cameras power and + * complete their bootstrapping process. This should be handled by the + * call to regulator_enable, but alas on V3M we end up in a circular + * dependency due to the regulator being connected to our own gpio_chip + * + * This sleep is a temporary work-around and should be removed, which + * ensures enough time has passed from the gpio_chip enabling a + * gpio-hog before we enable any reverse channels within max9286_setup. + */ + usleep_range(8000000, 9000000); + priv->poc_enabled = true; ret = max9286_setup(priv); -- 2.20.1
