[PATCH] iio: adc: rockchip_saradc: Explicitly disable ADC on probe

From: Guenter Roeck
Date: Mon Jul 25 2016 - 15:39:18 EST

If the ADC is read for the first time, the caller gets a timeout error,
and the kernel log shows

read channel() error: -110

The ADC may be enabled on boot, and needs to be explicitly disabled
for a read sequence to work (otherwise there is no completion interrupt).
Disaple it explicitly in the probe function.

Fixes: 44d6f2ef94f9 ("iio: adc: add driver for Rockchip saradc")
Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
drivers/iio/adc/rockchip_saradc.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/drivers/iio/adc/rockchip_saradc.c b/drivers/iio/adc/rockchip_saradc.c
index f9ad6c2d6821..6aa3271d86b5 100644
--- a/drivers/iio/adc/rockchip_saradc.c
+++ b/drivers/iio/adc/rockchip_saradc.c
@@ -280,6 +280,9 @@ static int rockchip_saradc_probe(struct platform_device *pdev)
goto err_pclk;

+ /* Make sure ADC is disabled */
+ writel_relaxed(0, info->regs + SARADC_CTRL);
platform_set_drvdata(pdev, indio_dev);

indio_dev->name = dev_name(&pdev->dev);