linux-kernel - [PATCH 3/5] mfd: ti_am335x_tscadc: Keep ADC interface on if child is wakeup capable

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Date:   Sat, 30 Jun 2018 16:03:16 +0530
From:   Vignesh R <vigneshr@...com>
To:     Jonathan Cameron <jic23@...nel.org>,
        Dmitry Torokhov <dmitry.torokhov@...il.com>,
        Lee Jones <lee.jones@...aro.org>
CC:     Vignesh R <vigneshr@...com>, <linux-iio@...r.kernel.org>,
        <linux-omap@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <linux-input@...r.kernel.org>
Subject: [PATCH 3/5] 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@...com>
---
 drivers/mfd/ti_am335x_tscadc.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/drivers/mfd/ti_am335x_tscadc.c b/drivers/mfd/ti_am335x_tscadc.c
index 858c1a071a81..c21ed54d1662 100644
--- a/drivers/mfd/ti_am335x_tscadc.c
+++ b/drivers/mfd/ti_am335x_tscadc.c
@@ -294,11 +294,24 @@ 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;
-- 
2.18.0