[PATCH v2 2/3] Input: ti_am335x_tsc: Add support for ti,charge-delay-ns

[Mugunthan V N]

ti,charge-delay will be deprecated as it represents number of
clock cycles and the DT entries are done in assumption of 3MHz
TSCADC clock, but clock can be set upto 24MHz. So driver add
support for ti,charge-delay-ns and do not drop support for
ti,charge-delay to support old dtbs and it will be assumed that
it is for 3MHz TSCADC clock and will be calculated as per current
clock speed.

Signed-off-by: Mugunthan V N <mugunthanvnm@xxxxxx>
---
 drivers/input/touchscreen/ti_am335x_tsc.c | 31 +++++++++++++++++++++++--------
 1 file changed, 23 insertions(+), 8 deletions(-)

diff --git a/drivers/input/touchscreen/ti_am335x_tsc.c b/drivers/input/touchscreen/ti_am335x_tsc.c
index 7953381d939a..104b3640f728 100644
--- a/drivers/input/touchscreen/ti_am335x_tsc.c
+++ b/drivers/input/touchscreen/ti_am335x_tsc.c
@@ -379,15 +379,30 @@ static int titsc_parse_dt(struct platform_device *pdev,
 		ts_dev->coordinate_readouts = 5;
 	}
 
-	err = of_property_read_u32(node, "ti,charge-delay",
+	err = of_property_read_u32(node, "ti,charge-delay-ns",
 				   &ts_dev->charge_delay);
-	/*
-	 * If ti,charge-delay value is not specified, then use
-	 * CHARGEDLY_OPENDLY as the default value.
-	 */
-	if (err < 0) {
-		ts_dev->charge_delay = CHARGEDLY_OPENDLY;
-		dev_warn(&pdev->dev, "ti,charge-delay not specified\n");
+	if (err >= 0) {
+		u64 charge_delay = ts_dev->charge_delay;
+
+		charge_delay *= ADC_CLK;
+		do_div(charge_delay, 1E9);
+		ts_dev->charge_delay = (u32)charge_delay;
+	} else {
+		err = of_property_read_u32(node, "ti,charge-delay",
+					   &ts_dev->charge_delay);
+		/*
+		 * If ti,charge-delay value is not specified, then use
+		 * CHARGEDLY_OPENDLY as the default value.
+		 */
+		if (err < 0) {
+			ts_dev->charge_delay = CHARGEDLY_OPENDLY;
+			dev_warn(&pdev->dev, "ti,charge-delay not specified\n");
+		}
+		/*
+		 * ti,charge-delay is specified with referrence to 3MHz,
+		 * so convert it to in referrence to current clock
+		 */
+		ts_dev->charge_delay *= ADC_CLK / 3000000;
 	}
 
 	return of_property_read_u32_array(node, "ti,wire-config",
-- 
2.11.0.rc0.7.gbe5a750