Input: bbnsm_pwrkey - add bbnsm power key support

The ON/OFF logic inside the BBNSM allows for connecting directly
into a PMIC or other voltage regulator device. The module has an
button input signal and a wakeup request input signal. It also
has two interrupts (set_pwr_off_irq and set_pwr_on_irq) and an
active-low PMIC enable (pmic_en_b) output.

Add the power key support for the ON/OFF button function found in
BBNSM module.

Signed-off-by: Jacky Bai <ping.bai@nxp.com>
Reviewed-by: Peng Fan <peng.fan@nxp.com>
Link: https://lore.kernel.org/r/20230215024117.3357341-2-ping.bai@nxp.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/misc/Kconfig

@@ -119,6 +119,17 @@ config INPUT_ATMEL_CAPTOUCH
 	  To compile this driver as a module, choose M here: the
 	  module will be called atmel_captouch.
 
+config INPUT_BBNSM_PWRKEY
+	tristate "NXP BBNSM Power Key Driver"
+	depends on ARCH_MXC || COMPILE_TEST
+	depends on OF
+	help
+	  This is the bbnsm powerkey driver for the NXP i.MX application
+	  processors.
+
+	  To compile this driver as a module, choose M here; the
+	  module will be called bbnsm_pwrkey.
+
 config INPUT_BMA150
 	tristate "BMA150/SMB380 acceleration sensor support"
 	depends on I2C

drivers/input/misc/Makefile

@@ -21,6 +21,7 @@ obj-$(CONFIG_INPUT_ATC260X_ONKEY)	+= atc260x-onkey.o
 obj-$(CONFIG_INPUT_ATI_REMOTE2)		+= ati_remote2.o
 obj-$(CONFIG_INPUT_ATLAS_BTNS)		+= atlas_btns.o
 obj-$(CONFIG_INPUT_ATMEL_CAPTOUCH)	+= atmel_captouch.o
+obj-$(CONFIG_INPUT_BBNSM_PWRKEY)	+= nxp-bbnsm-pwrkey.o
 obj-$(CONFIG_INPUT_BMA150)		+= bma150.o
 obj-$(CONFIG_INPUT_CM109)		+= cm109.o
 obj-$(CONFIG_INPUT_CMA3000)		+= cma3000_d0x.o

drivers/input/misc/nxp-bbnsm-pwrkey.c

@@ -0,0 +1,193 @@
+// SPDX-License-Identifier: GPL-2.0+
+//
+// Copyright 2022 NXP.
+
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/input.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/jiffies.h>
+#include <linux/kernel.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/pm_wakeirq.h>
+#include <linux/regmap.h>
+
+#define BBNSM_CTRL		0x8
+#define BBNSM_INT_EN		0x10
+#define BBNSM_EVENTS		0x14
+#define BBNSM_PAD_CTRL		0x24
+
+#define BBNSM_BTN_PRESSED	BIT(7)
+#define BBNSM_PWR_ON		BIT(6)
+#define BBNSM_BTN_OFF		BIT(5)
+#define BBNSM_EMG_OFF		BIT(4)
+#define BBNSM_PWRKEY_EVENTS	(BBNSM_PWR_ON | BBNSM_BTN_OFF | BBNSM_EMG_OFF)
+#define BBNSM_DP_EN		BIT(24)
+
+#define DEBOUNCE_TIME		30
+#define REPEAT_INTERVAL		60
+
+struct bbnsm_pwrkey {
+	struct regmap *regmap;
+	int irq;
+	int keycode;
+	int keystate;  /* 1:pressed */
+	struct timer_list check_timer;
+	struct input_dev *input;
+};
+
+static void bbnsm_pwrkey_check_for_events(struct timer_list *t)
+{
+	struct bbnsm_pwrkey *bbnsm = from_timer(bbnsm, t, check_timer);
+	struct input_dev *input = bbnsm->input;
+	u32 state;
+
+	regmap_read(bbnsm->regmap, BBNSM_EVENTS, &state);
+
+	state = state & BBNSM_BTN_PRESSED ? 1 : 0;
+
+	/* only report new event if status changed */
+	if (state ^ bbnsm->keystate) {
+		bbnsm->keystate = state;
+		input_event(input, EV_KEY, bbnsm->keycode, state);
+		input_sync(input);
+		pm_relax(bbnsm->input->dev.parent);
+	}
+
+	/* repeat check if pressed long */
+	if (state)
+		mod_timer(&bbnsm->check_timer,
+			  jiffies + msecs_to_jiffies(REPEAT_INTERVAL));
+}
+
+static irqreturn_t bbnsm_pwrkey_interrupt(int irq, void *dev_id)
+{
+	struct platform_device *pdev = dev_id;
+	struct bbnsm_pwrkey *bbnsm = platform_get_drvdata(pdev);
+	u32 event;
+
+	regmap_read(bbnsm->regmap, BBNSM_EVENTS, &event);
+	if (!(event & BBNSM_BTN_OFF))
+		return IRQ_NONE;
+
+	pm_wakeup_event(bbnsm->input->dev.parent, 0);
+
+	mod_timer(&bbnsm->check_timer,
+		   jiffies + msecs_to_jiffies(DEBOUNCE_TIME));
+
+	/* clear PWR OFF */
+	regmap_write(bbnsm->regmap, BBNSM_EVENTS, BBNSM_BTN_OFF);
+
+	return IRQ_HANDLED;
+}
+
+static void bbnsm_pwrkey_act(void *pdata)
+{
+	struct bbnsm_pwrkey *bbnsm = pdata;
+
+	timer_shutdown_sync(&bbnsm->check_timer);
+}
+
+static int bbnsm_pwrkey_probe(struct platform_device *pdev)
+{
+	struct bbnsm_pwrkey *bbnsm;
+	struct input_dev *input;
+	struct device_node *np = pdev->dev.of_node;
+	int error;
+
+	bbnsm = devm_kzalloc(&pdev->dev, sizeof(*bbnsm), GFP_KERNEL);
+	if (!bbnsm)
+		return -ENOMEM;
+
+	bbnsm->regmap = syscon_node_to_regmap(np->parent);
+	if (IS_ERR(bbnsm->regmap)) {
+		dev_err(&pdev->dev, "bbnsm pwerkey get regmap failed\n");
+		return PTR_ERR(bbnsm->regmap);
+	}
+
+	if (device_property_read_u32(&pdev->dev, "linux,code",
+				     &bbnsm->keycode)) {
+		bbnsm->keycode = KEY_POWER;
+		dev_warn(&pdev->dev, "key code is not specified, using default KEY_POWER\n");
+	}
+
+	bbnsm->irq = platform_get_irq(pdev, 0);
+	if (bbnsm->irq < 0)
+		return -EINVAL;
+
+	/* config the BBNSM power related register */
+	regmap_update_bits(bbnsm->regmap, BBNSM_CTRL, BBNSM_DP_EN, BBNSM_DP_EN);
+
+	/* clear the unexpected interrupt before driver ready */
+	regmap_write_bits(bbnsm->regmap, BBNSM_EVENTS, BBNSM_PWRKEY_EVENTS,
+			  BBNSM_PWRKEY_EVENTS);
+
+	timer_setup(&bbnsm->check_timer, bbnsm_pwrkey_check_for_events, 0);
+
+	input = devm_input_allocate_device(&pdev->dev);
+	if (!input) {
+		dev_err(&pdev->dev, "failed to allocate the input device\n");
+		return -ENOMEM;
+	}
+
+	input->name = pdev->name;
+	input->phys = "bbnsm-pwrkey/input0";
+	input->id.bustype = BUS_HOST;
+
+	input_set_capability(input, EV_KEY, bbnsm->keycode);
+
+	/* input customer action to cancel release timer */
+	error = devm_add_action(&pdev->dev, bbnsm_pwrkey_act, bbnsm);
+	if (error) {
+		dev_err(&pdev->dev, "failed to register remove action\n");
+		return error;
+	}
+
+	bbnsm->input = input;
+	platform_set_drvdata(pdev, bbnsm);
+
+	error = devm_request_irq(&pdev->dev, bbnsm->irq, bbnsm_pwrkey_interrupt,
+				 IRQF_SHARED, pdev->name, pdev);
+	if (error) {
+		dev_err(&pdev->dev, "interrupt not available.\n");
+		return error;
+	}
+
+	error = input_register_device(input);
+	if (error) {
+		dev_err(&pdev->dev, "failed to register input device\n");
+		return error;
+	}
+
+	device_init_wakeup(&pdev->dev, true);
+	error = dev_pm_set_wake_irq(&pdev->dev, bbnsm->irq);
+	if (error)
+		dev_warn(&pdev->dev, "irq wake enable failed.\n");
+
+	return 0;
+}
+
+static const struct of_device_id bbnsm_pwrkey_ids[] = {
+	{ .compatible = "nxp,imx93-bbnsm-pwrkey" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, bbnsm_pwrkey_ids);
+
+static struct platform_driver bbnsm_pwrkey_driver = {
+	.driver = {
+		.name = "bbnsm_pwrkey",
+		.of_match_table = bbnsm_pwrkey_ids,
+	},
+	.probe = bbnsm_pwrkey_probe,
+};
+module_platform_driver(bbnsm_pwrkey_driver);
+
+MODULE_AUTHOR("Jacky Bai <ping.bai@nxp.com>");
+MODULE_DESCRIPTION("NXP bbnsm power key Driver");
+MODULE_LICENSE("GPL");