Hi Mike,
On Mon, Jul 03, 2023 at 10:45:36AM +0200, Mike Looijmans wrote:
Add power supply regulator support to the exc3000 devices.
Signed-off-by: Mike Looijmans <mike.looijmans@xxxxxxxx>
---
drivers/input/touchscreen/exc3000.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/drivers/input/touchscreen/exc3000.c b/drivers/input/touchscreen/exc3000.c
index 4af4c1e5d0da..3e50af8a4a2d 100644
--- a/drivers/input/touchscreen/exc3000.c
+++ b/drivers/input/touchscreen/exc3000.c
@@ -18,6 +18,7 @@
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/of.h>
+#include <linux/regulator/consumer.h>
#include <linux/sizes.h>
#include <linux/timer.h>
#include <asm/unaligned.h>
@@ -360,6 +361,12 @@ static int exc3000_probe(struct i2c_client *client)
if (IS_ERR(data->reset))
return PTR_ERR(data->reset);
+ /* For proper reset sequence, enable power while reset asserted */
+ error = devm_regulator_get_enable_optional(&client->dev, "vdd");
+ if (error && error != -ENODEV)
+ dev_err_probe(&client->dev, error,
+ "failed to request vdd regulator\n");
If there is a regulator described in the firmware we should not continue
with initializing the device if we fail to grab/enable it. Think about
what happens if you get -EPROBE_DEFER here. You should return here.
Also, why are you using the _optional() variant? VDD is not an optional
for the controller. regulator_get_optional() is needed when you need to
alter the behavior of the device/driver depending on the presence of an
optional supply, whereas here it should work fine with a sub supply that
will be created if you simply call devm_regulator_get_enable() and there
is not regulator mentioned in DT/ACPI for the board.