[PATCH v4 4/6] nfc: s3fwrn5: enable the PVDD supply

The controller is powered by an externally switched PVDD rail. Get and
enable it in the i2c phy probe, before any of the chip's pins is driven
or its clock started, so the chip's power does not depend on whatever
state the bootloader or platform left the rail in. Boards that do not
describe the supply resolve to a dummy regulator, so the existing users
keep working; they gain the regulator core's dummy-supply warning until
their DTs describe the rail.

Assisted-by: Claude:claude-fable-5
Signed-off-by: Jorijn van der Graaf <[email protected]>
---
 drivers/nfc/s3fwrn5/i2c.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/nfc/s3fwrn5/i2c.c b/drivers/nfc/s3fwrn5/i2c.c
index c528c085b43e..f93d8b47b65e 100644
--- a/drivers/nfc/s3fwrn5/i2c.c
+++ b/drivers/nfc/s3fwrn5/i2c.c
@@ -11,6 +11,7 @@
 #include <linux/gpio/consumer.h>
 #include <linux/delay.h>
 #include <linux/module.h>
+#include <linux/regulator/consumer.h>
 
 #include <net/nfc/nfc.h>
 
@@ -158,6 +159,11 @@ static int s3fwrn5_i2c_probe(struct i2c_client *client)
 	phy->i2c_dev = client;
 	i2c_set_clientdata(client, phy);
 
+	ret = devm_regulator_get_enable(&client->dev, "pvdd");
+	if (ret)
+		return dev_err_probe(&client->dev, ret,
+				     "failed to enable pvdd\n");
+
 	phy->common.gpio_en = devm_gpiod_get(&client->dev, "en", GPIOD_OUT_HIGH);
 	if (IS_ERR(phy->common.gpio_en))
 		return PTR_ERR(phy->common.gpio_en);
-- 
2.55.0