mfd: ti_am335x_tscadc: Keep ADC interface on if child is wakeup capable

If a child device like touchscreen is wakeup capable, then keep ADC
interface on, so that a touching resistive screen will generate wakeup
event to the system.

Signed-off-by: Vignesh R <vigneshr@ti.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

1 files changed, 13 insertions, 0 deletions

diff --git a/drivers/mfd/ti_am335x_tscadc.c b/drivers/mfd/ti_am335x_tscadc.c
index ee3ffd96f5d2..c2d47d78705b 100644
--- a/drivers/mfd/ti_am335x_tscadc.c
+++ b/drivers/mfd/ti_am335x_tscadc.c
@@ -293,11 +293,24 @@ static int ti_tscadc_remove(struct platform_device *pdev)
         return 0;
 }
 
+static int __maybe_unused ti_tscadc_can_wakeup(struct device *dev, void *data)
+{
+        return device_may_wakeup(dev);
+}
+
 static int __maybe_unused tscadc_suspend(struct device *dev)
 {
         struct ti_tscadc_dev    *tscadc = dev_get_drvdata(dev);
 
         regmap_write(tscadc->regmap, REG_SE, 0x00);
+        if (device_for_each_child(dev, NULL, ti_tscadc_can_wakeup)) {
+                u32 ctrl;
+
+                regmap_read(tscadc->regmap, REG_CTRL, &ctrl);
+                ctrl &= ~(CNTRLREG_POWERDOWN);
+                ctrl |= CNTRLREG_TSCSSENB;
+                regmap_write(tscadc->regmap, REG_CTRL, ctrl);
+        }
         pm_runtime_put_sync(dev);
 
         return 0;