[PATCH] adp5588-keys: Support for dedicated gpio operation

[Agarwal, Utsav]

From: UtsavAgarwalADI <utsav.agarwal@xxxxxxxxxx>

We have a SoC which uses ADP5587 exclusively as an I2C GPIO expander.
The current state of the driver for the ADP5588/87 only allows
partial I/O to be used as GPIO. This support was present before as a
separate gpio driver, which was dropped with the commit
5ddc896088b0 ("gpio: gpio-adp5588: drop the driver") since the
functionality was deemed to have been merged with adp5588-keys.

To restore this functionality, the "gpio-only" property allows
indicating if the device is to be used for GPIO only.
When specified, the driver skips relevant input device
checks/parsing and allows all GPINS to be registered as GPIO.

Signed-off-by: Utsav Agarwal <utsav.agarwal@xxxxxxxxxx>
---
 drivers/input/keyboard/adp5588-keys.c | 30 ++++++++++++++++++++-------
 1 file changed, 23 insertions(+), 7 deletions(-)

diff --git a/drivers/input/keyboard/adp5588-keys.c b/drivers/input/keyboard/adp5588-keys.c
index 1b0279393df4..78770b2dfe1b 100644
--- a/drivers/input/keyboard/adp5588-keys.c
+++ b/drivers/input/keyboard/adp5588-keys.c
@@ -719,7 +719,7 @@ static int adp5588_probe(struct i2c_client *client)
 	struct input_dev *input;
 	struct gpio_desc *gpio;
 	unsigned int revid;
-	int ret;
+	int ret, gpio_mode_only;
 	int error;
 
 	if (!i2c_check_functionality(client->adapter,
@@ -739,13 +739,17 @@ static int adp5588_probe(struct i2c_client *client)
 	kpad->client = client;
 	kpad->input = input;
 
-	error = adp5588_fw_parse(kpad);
-	if (error)
-		return error;
+	gpio_mode_only = device_property_present(&client->dev, "gpio-only");
+	if (!gpio_mode_only) {
+		error = adp5588_fw_parse(kpad);
+		if (error)
+			return error;
 
-	error = devm_regulator_get_enable(&client->dev, "vcc");
-	if (error)
-		return error;
+		error = devm_regulator_get_enable(&client->dev, "vcc");
+		if (error)
+			return error;
+
+	}
 
 	gpio = devm_gpiod_get_optional(&client->dev, "reset", GPIOD_OUT_HIGH);
 	if (IS_ERR(gpio))
@@ -790,6 +794,11 @@ static int adp5588_probe(struct i2c_client *client)
 	if (error)
 		return error;
 
+	if (!client->irq && gpio_mode_only) {
+		dev_info(&client->dev, "Rev.%d, started as GPIO only\n", revid);
+		return 0;
+	}
+
 	error = devm_request_threaded_irq(&client->dev, client->irq,
 					  adp5588_hard_irq, adp5588_thread_irq,
 					  IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
@@ -800,6 +809,13 @@ static int adp5588_probe(struct i2c_client *client)
 		return error;
 	}
 
+
+	if (gpio_mode_only) {
+		dev_info(&client->dev, "Rev.%d irq %d, started as GPIO only\n",
+				revid, client->irq);
+		return 0;
+	}
+
 	dev_info(&client->dev, "Rev.%d keypad, irq %d\n", revid, client->irq);
 	return 0;
 }
-- 
2.34.1