[RFC PATCH v4 4/5] input: add onkey driver for Marvell 88PM886 PMIC

[Karel Balej <karelb@gimli.ms.mff.cuni.cz>]

From: Karel Balej <balejk@matfyz.cz>

Marvell 88PM886 PMIC provides onkey among other things. Add client
driver to handle it. The driver currently only provides a basic support
omitting additional functions found in the vendor version, such as long
onkey and GPIO integration.

Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Karel Balej <balejk@matfyz.cz>
---

Notes:
    RFC v4:
    - Reflect MFD driver changes:
      - chip->regmaps[...] -> chip->regmap
    - Address Dmitry's feedback:
      - Add ID table.
      - Add Ack.
    RFC v3:
    - Drop wakeup-source.
    RFC v2:
    - Address Dmitry's feedback:
      - Sort includes alphabetically.
      - Drop onkey->irq.
      - ret -> err in irq_handler and no initialization.
      - Break long lines and other formatting.
      - Do not clobber platform_get_irq error.
      - Do not set device parent manually.
      - Use input_set_capability.
      - Use the wakeup-source DT property.
      - Drop of_match_table.
      - Use more temporaries.
      - Use dev_err_probe.
    - Modify Kconfig description.

 drivers/input/misc/88pm886-onkey.c | 99 ++++++++++++++++++++++++++++++
 drivers/input/misc/Kconfig         |  7 +++
 drivers/input/misc/Makefile        |  1 +
 3 files changed, 107 insertions(+)
 create mode 100644 drivers/input/misc/88pm886-onkey.c

diff --git a/drivers/input/misc/88pm886-onkey.c b/drivers/input/misc/88pm886-onkey.c
new file mode 100644
index 000000000000..b0bfbd57d826
--- /dev/null
+++ b/drivers/input/misc/88pm886-onkey.c
@@ -0,0 +1,99 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/input.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+#include <linux/mfd/88pm886.h>
+
+struct pm886_onkey {
+	struct input_dev *idev;
+	struct pm886_chip *chip;
+};
+
+static irqreturn_t pm886_onkey_irq_handler(int irq, void *data)
+{
+	struct pm886_onkey *onkey = data;
+	struct regmap *regmap = onkey->chip->regmap;
+	struct input_dev *idev = onkey->idev;
+	struct device *parent = idev->dev.parent;
+	unsigned int val;
+	int err;
+
+	err = regmap_read(regmap, PM886_REG_STATUS1, &val);
+	if (err) {
+		dev_err(parent, "Failed to read status: %d\n", err);
+		return IRQ_NONE;
+	}
+	val &= PM886_ONKEY_STS1;
+
+	input_report_key(idev, KEY_POWER, val);
+	input_sync(idev);
+
+	return IRQ_HANDLED;
+}
+
+static int pm886_onkey_probe(struct platform_device *pdev)
+{
+	struct pm886_chip *chip = dev_get_drvdata(pdev->dev.parent);
+	struct device *dev = &pdev->dev;
+	struct pm886_onkey *onkey;
+	struct input_dev *idev;
+	int irq, err;
+
+	onkey = devm_kzalloc(dev, sizeof(*onkey), GFP_KERNEL);
+	if (!onkey)
+		return -ENOMEM;
+
+	onkey->chip = chip;
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0)
+		return dev_err_probe(dev, irq, "Failed to get IRQ\n");
+
+	idev = devm_input_allocate_device(dev);
+	if (!idev) {
+		dev_err(dev, "Failed to allocate input device\n");
+		return -ENOMEM;
+	}
+	onkey->idev = idev;
+
+	idev->name = "88pm886-onkey";
+	idev->phys = "88pm886-onkey/input0";
+	idev->id.bustype = BUS_I2C;
+
+	input_set_capability(idev, EV_KEY, KEY_POWER);
+
+	err = devm_request_threaded_irq(dev, irq, NULL, pm886_onkey_irq_handler,
+					IRQF_ONESHOT | IRQF_NO_SUSPEND, "onkey",
+					onkey);
+	if (err)
+		return dev_err_probe(dev, err, "Failed to request IRQ\n");
+
+	err = input_register_device(idev);
+	if (err)
+		return dev_err_probe(dev, err, "Failed to register input device\n");
+
+	return 0;
+}
+
+static const struct platform_device_id pm886_onkey_id_table[] = {
+	{ "88pm886-onkey", },
+	{ }
+};
+MODULE_DEVICE_TABLE(platform, pm886_onkey_id_table);
+
+static struct platform_driver pm886_onkey_driver = {
+	.driver = {
+		.name = "88pm886-onkey",
+	},
+	.probe = pm886_onkey_probe,
+	.id_table = pm886_onkey_id_table,
+};
+module_platform_driver(pm886_onkey_driver);
+
+MODULE_DESCRIPTION("Marvell 88PM886 onkey driver");
+MODULE_AUTHOR("Karel Balej <balejk@matfyz.cz>");
+MODULE_LICENSE("GPL");
diff --git a/drivers/input/misc/Kconfig b/drivers/input/misc/Kconfig
index 6ba984d7f0b1..16a079d9f0f2 100644
--- a/drivers/input/misc/Kconfig
+++ b/drivers/input/misc/Kconfig
@@ -33,6 +33,13 @@ config INPUT_88PM80X_ONKEY
 	  To compile this driver as a module, choose M here: the module
 	  will be called 88pm80x_onkey.
 
+config INPUT_88PM886_ONKEY
+	tristate "Marvell 88PM886 onkey support"
+	depends on MFD_88PM886_PMIC
+	help
+	  Support the onkey of Marvell 88PM886 PMIC as an input device
+	  reporting power button status.
+
 config INPUT_AB8500_PONKEY
 	tristate "AB8500 Pon (PowerOn) Key"
 	depends on AB8500_CORE
diff --git a/drivers/input/misc/Makefile b/drivers/input/misc/Makefile
index 04296a4abe8e..054a6dc1ac27 100644
--- a/drivers/input/misc/Makefile
+++ b/drivers/input/misc/Makefile
@@ -7,6 +7,7 @@
 
 obj-$(CONFIG_INPUT_88PM860X_ONKEY)	+= 88pm860x_onkey.o
 obj-$(CONFIG_INPUT_88PM80X_ONKEY)	+= 88pm80x_onkey.o
+obj-$(CONFIG_INPUT_88PM886_ONKEY)	+= 88pm886-onkey.o
 obj-$(CONFIG_INPUT_AB8500_PONKEY)	+= ab8500-ponkey.o
 obj-$(CONFIG_INPUT_AD714X)		+= ad714x.o
 obj-$(CONFIG_INPUT_AD714X_I2C)		+= ad714x-i2c.o
-- 
2.44.0