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/* Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 and
 * only version 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/input.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/log2.h>
#include <linux/of.h>
#include <linux/of_device.h>

#define PON_CNTL_1 0x1C
#define PON_CNTL_PULL_UP BIT(7)
#define PON_CNTL_TRIG_DELAY_MASK (0x7)
#define PON_CNTL_1_PULL_UP_EN			0xe0
#define PON_CNTL_1_USB_PWR_EN			0x10
#define PON_CNTL_1_WD_EN_RESET			0x08

#define PM8058_SLEEP_CTRL			0x02b
#define PM8921_SLEEP_CTRL			0x10a

#define SLEEP_CTRL_SMPL_EN_RESET		0x04

/* Regulator master enable addresses */
#define REG_PM8058_VREG_EN_MSM			0x018
#define REG_PM8058_VREG_EN_GRP_5_4		0x1c8

/* Regulator control registers for shutdown/reset */
#define PM8058_S0_CTRL				0x004
#define PM8058_S1_CTRL				0x005
#define PM8058_S3_CTRL				0x111
#define PM8058_L21_CTRL				0x120
#define PM8058_L22_CTRL				0x121

#define PM8058_REGULATOR_ENABLE_MASK		0x80
#define PM8058_REGULATOR_ENABLE			0x80
#define PM8058_REGULATOR_DISABLE		0x00
#define PM8058_REGULATOR_PULL_DOWN_MASK		0x40
#define PM8058_REGULATOR_PULL_DOWN_EN		0x40

/* Buck CTRL register */
#define PM8058_SMPS_LEGACY_VREF_SEL		0x20
#define PM8058_SMPS_LEGACY_VPROG_MASK		0x1f
#define PM8058_SMPS_ADVANCED_BAND_MASK		0xC0
#define PM8058_SMPS_ADVANCED_BAND_SHIFT		6
#define PM8058_SMPS_ADVANCED_VPROG_MASK		0x3f

/* Buck TEST2 registers for shutdown/reset */
#define PM8058_S0_TEST2				0x084
#define PM8058_S1_TEST2				0x085
#define PM8058_S3_TEST2				0x11a

#define PM8058_REGULATOR_BANK_WRITE		0x80
#define PM8058_REGULATOR_BANK_MASK		0x70
#define PM8058_REGULATOR_BANK_SHIFT		4
#define PM8058_REGULATOR_BANK_SEL(n)	((n) << PM8058_REGULATOR_BANK_SHIFT)

/* Buck TEST2 register bank 1 */
#define PM8058_SMPS_LEGACY_VLOW_SEL		0x01

/* Buck TEST2 register bank 7 */
#define PM8058_SMPS_ADVANCED_MODE_MASK		0x02
#define PM8058_SMPS_ADVANCED_MODE		0x02
#define PM8058_SMPS_LEGACY_MODE			0x00

/**
 * struct pmic8xxx_pwrkey - pmic8xxx pwrkey information
 * @key_press_irq: key press irq number
 * @regmap: device regmap
 * @shutdown_fn: shutdown configuration function
 */
struct pmic8xxx_pwrkey {
	int key_press_irq;
	struct regmap *regmap;
	int (*shutdown_fn)(struct pmic8xxx_pwrkey *, bool);
};

static irqreturn_t pwrkey_press_irq(int irq, void *_pwr)
{
	struct input_dev *pwr = _pwr;

	input_report_key(pwr, KEY_POWER, 1);
	input_sync(pwr);

	return IRQ_HANDLED;
}

static irqreturn_t pwrkey_release_irq(int irq, void *_pwr)
{
	struct input_dev *pwr = _pwr;

	input_report_key(pwr, KEY_POWER, 0);
	input_sync(pwr);

	return IRQ_HANDLED;
}

static int __maybe_unused pmic8xxx_pwrkey_suspend(struct device *dev)
{
	struct pmic8xxx_pwrkey *pwrkey = dev_get_drvdata(dev);

	if (device_may_wakeup(dev))
		enable_irq_wake(pwrkey->key_press_irq);

	return 0;
}

static int __maybe_unused pmic8xxx_pwrkey_resume(struct device *dev)
{
	struct pmic8xxx_pwrkey *pwrkey = dev_get_drvdata(dev);

	if (device_may_wakeup(dev))
		disable_irq_wake(pwrkey->key_press_irq);

	return 0;
}

static SIMPLE_DEV_PM_OPS(pm8xxx_pwr_key_pm_ops,
		pmic8xxx_pwrkey_suspend, pmic8xxx_pwrkey_resume);

static void pmic8xxx_pwrkey_shutdown(struct platform_device *pdev)
{
	struct pmic8xxx_pwrkey *pwrkey = platform_get_drvdata(pdev);
	int error;
	u8 mask, val;
	bool reset = system_state == SYSTEM_RESTART;

	if (pwrkey->shutdown_fn) {
		error = pwrkey->shutdown_fn(pwrkey, reset);
		if (error)
			return;
	}

	/*
	 * Select action to perform (reset or shutdown) when PS_HOLD goes low.
	 * Also ensure that KPD, CBL0, and CBL1 pull ups are enabled and that
	 * USB charging is enabled.
	 */
	mask = PON_CNTL_1_PULL_UP_EN | PON_CNTL_1_USB_PWR_EN;
	mask |= PON_CNTL_1_WD_EN_RESET;
	val = mask;
	if (!reset)
		val &= ~PON_CNTL_1_WD_EN_RESET;

	regmap_update_bits(pwrkey->regmap, PON_CNTL_1, mask, val);
}

/*
 * Set an SMPS regulator to be disabled in its CTRL register, but enabled
 * in the master enable register.  Also set it's pull down enable bit.
 * Take care to make sure that the output voltage doesn't change if switching
 * from advanced mode to legacy mode.
 */
static int pm8058_disable_smps_locally_set_pull_down(struct regmap *regmap,
	u16 ctrl_addr, u16 test2_addr, u16 master_enable_addr,
	u8 master_enable_bit)
{
	int error;
	u8 vref_sel, vlow_sel, band, vprog, bank;
	unsigned int reg;

	bank = PM8058_REGULATOR_BANK_SEL(7);
	error = regmap_write(regmap, test2_addr, bank);
	if (error)
		return error;

	error = regmap_read(regmap, test2_addr, &reg);
	if (error)
		return error;

	reg &= PM8058_SMPS_ADVANCED_MODE_MASK;
	/* Check if in advanced mode. */
	if (reg == PM8058_SMPS_ADVANCED_MODE) {
		/* Determine current output voltage. */
		error = regmap_read(regmap, ctrl_addr, &reg);
		if (error)
			return error;

		band = reg & PM8058_SMPS_ADVANCED_BAND_MASK;
		band >>= PM8058_SMPS_ADVANCED_BAND_SHIFT;
		switch (band) {
		case 3:
			vref_sel = 0;
			vlow_sel = 0;
			break;
		case 2:
			vref_sel = PM8058_SMPS_LEGACY_VREF_SEL;
			vlow_sel = 0;
			break;
		case 1:
			vref_sel = PM8058_SMPS_LEGACY_VREF_SEL;
			vlow_sel = PM8058_SMPS_LEGACY_VLOW_SEL;
			break;
		default:
			pr_err("%s: regulator already disabled\n", __func__);
			return -EPERM;
		}
		vprog = reg & PM8058_SMPS_ADVANCED_VPROG_MASK;
		/* Round up if fine step is in use. */
		vprog = (vprog + 1) >> 1;
		if (vprog > PM8058_SMPS_LEGACY_VPROG_MASK)
			vprog = PM8058_SMPS_LEGACY_VPROG_MASK;

		/* Set VLOW_SEL bit. */
		bank = PM8058_REGULATOR_BANK_SEL(1);
		error = regmap_write(regmap, test2_addr, bank);
		if (error)
			return error;

		error = regmap_update_bits(regmap, test2_addr,
			PM8058_REGULATOR_BANK_WRITE | PM8058_REGULATOR_BANK_MASK
				| PM8058_SMPS_LEGACY_VLOW_SEL,
			PM8058_REGULATOR_BANK_WRITE |
			PM8058_REGULATOR_BANK_SEL(1) | vlow_sel);
		if (error)
			return error;

		/* Switch to legacy mode */
		bank = PM8058_REGULATOR_BANK_SEL(7);
		error = regmap_write(regmap, test2_addr, bank);
		if (error)
			return error;

		error = regmap_update_bits(regmap, test2_addr,
				PM8058_REGULATOR_BANK_WRITE |
				PM8058_REGULATOR_BANK_MASK |
				PM8058_SMPS_ADVANCED_MODE_MASK,
				PM8058_REGULATOR_BANK_WRITE |
				PM8058_REGULATOR_BANK_SEL(7) |
				PM8058_SMPS_LEGACY_MODE);
		if (error)
			return error;

		/* Enable locally, enable pull down, keep voltage the same. */
		error = regmap_update_bits(regmap, ctrl_addr,
			PM8058_REGULATOR_ENABLE_MASK |
			PM8058_REGULATOR_PULL_DOWN_MASK |
			PM8058_SMPS_LEGACY_VREF_SEL |
			PM8058_SMPS_LEGACY_VPROG_MASK,
			PM8058_REGULATOR_ENABLE | PM8058_REGULATOR_PULL_DOWN_EN
				| vref_sel | vprog);
		if (error)
			return error;
	}

	/* Enable in master control register. */
	error = regmap_update_bits(regmap, master_enable_addr,
			master_enable_bit, master_enable_bit);
	if (error)
		return error;

	/* Disable locally and enable pull down. */
	return regmap_update_bits(regmap, ctrl_addr,
		PM8058_REGULATOR_ENABLE_MASK | PM8058_REGULATOR_PULL_DOWN_MASK,
		PM8058_REGULATOR_DISABLE | PM8058_REGULATOR_PULL_DOWN_EN);
}

static int pm8058_disable_ldo_locally_set_pull_down(struct regmap *regmap,
		u16 ctrl_addr, u16 master_enable_addr, u8 master_enable_bit)
{
	int error;

	/* Enable LDO in master control register. */
	error = regmap_update_bits(regmap, master_enable_addr,
			master_enable_bit, master_enable_bit);
	if (error)
		return error;

	/* Disable LDO in CTRL register and set pull down */
	return regmap_update_bits(regmap, ctrl_addr,
		PM8058_REGULATOR_ENABLE_MASK | PM8058_REGULATOR_PULL_DOWN_MASK,
		PM8058_REGULATOR_DISABLE | PM8058_REGULATOR_PULL_DOWN_EN);
}

static int pm8058_pwrkey_shutdown(struct pmic8xxx_pwrkey *pwrkey, bool reset)
{
	int error;
	struct regmap *regmap = pwrkey->regmap;
	u8 mask, val;

	/* When shutting down, enable active pulldowns on important rails. */
	if (!reset) {
		/* Disable SMPS's 0,1,3 locally and set pulldown enable bits. */
		pm8058_disable_smps_locally_set_pull_down(regmap,
			PM8058_S0_CTRL, PM8058_S0_TEST2,
			REG_PM8058_VREG_EN_MSM, BIT(7));
		pm8058_disable_smps_locally_set_pull_down(regmap,
			PM8058_S1_CTRL, PM8058_S1_TEST2,
			REG_PM8058_VREG_EN_MSM, BIT(6));
		pm8058_disable_smps_locally_set_pull_down(regmap,
			PM8058_S3_CTRL, PM8058_S3_TEST2,
			REG_PM8058_VREG_EN_GRP_5_4, BIT(7) | BIT(4));
		/* Disable LDO 21 locally and set pulldown enable bit. */
		pm8058_disable_ldo_locally_set_pull_down(regmap,
			PM8058_L21_CTRL, REG_PM8058_VREG_EN_GRP_5_4,
			BIT(1));
	}

	/*
	 * Fix-up: Set regulator LDO22 to 1.225 V in high power mode. Leave its
	 * pull-down state intact. This ensures a safe shutdown.
	 */
	error = regmap_update_bits(regmap, PM8058_L22_CTRL, 0xbf, 0x93);
	if (error)
		return error;

	/* Enable SMPL if resetting is desired */
	mask = SLEEP_CTRL_SMPL_EN_RESET;
	val = 0;
	if (reset)
		val = mask;
	return regmap_update_bits(regmap, PM8058_SLEEP_CTRL, mask, val);
}

static int pm8921_pwrkey_shutdown(struct pmic8xxx_pwrkey *pwrkey, bool reset)
{
	struct regmap *regmap = pwrkey->regmap;
	u8 mask = SLEEP_CTRL_SMPL_EN_RESET;
	u8 val = 0;

	/* Enable SMPL if resetting is desired */
	if (reset)
		val = mask;
	return regmap_update_bits(regmap, PM8921_SLEEP_CTRL, mask, val);
}

static int pmic8xxx_pwrkey_probe(struct platform_device *pdev)
{
	struct input_dev *pwr;
	int key_release_irq = platform_get_irq(pdev, 0);
	int key_press_irq = platform_get_irq(pdev, 1);
	int err;
	unsigned int delay;
	unsigned int pon_cntl;
	struct regmap *regmap;
	struct pmic8xxx_pwrkey *pwrkey;
	u32 kpd_delay;
	bool pull_up;

	if (of_property_read_u32(pdev->dev.of_node, "debounce", &kpd_delay))
		kpd_delay = 15625;

	/* Valid range of pwr key trigger delay is 1/64 sec to 2 seconds. */
	if (kpd_delay > USEC_PER_SEC * 2 || kpd_delay < USEC_PER_SEC / 64) {
		dev_err(&pdev->dev, "invalid power key trigger delay\n");
		return -EINVAL;
	}

	pull_up = of_property_read_bool(pdev->dev.of_node, "pull-up");

	regmap = dev_get_regmap(pdev->dev.parent, NULL);
	if (!regmap) {
		dev_err(&pdev->dev, "failed to locate regmap for the device\n");
		return -ENODEV;
	}

	pwrkey = devm_kzalloc(&pdev->dev, sizeof(*pwrkey), GFP_KERNEL);
	if (!pwrkey)
		return -ENOMEM;

	pwrkey->shutdown_fn = of_device_get_match_data(&pdev->dev);
	pwrkey->regmap = regmap;
	pwrkey->key_press_irq = key_press_irq;

	pwr = devm_input_allocate_device(&pdev->dev);
	if (!pwr) {
		dev_dbg(&pdev->dev, "Can't allocate power button\n");
		return -ENOMEM;
	}

	input_set_capability(pwr, EV_KEY, KEY_POWER);

	pwr->name = "pmic8xxx_pwrkey";
	pwr->phys = "pmic8xxx_pwrkey/input0";

	delay = (kpd_delay << 6) / USEC_PER_SEC;
	delay = ilog2(delay);

	err = regmap_read(regmap, PON_CNTL_1, &pon_cntl);
	if (err < 0) {
		dev_err(&pdev->dev, "failed reading PON_CNTL_1 err=%d\n", err);
		return err;
	}

	pon_cntl &= ~PON_CNTL_TRIG_DELAY_MASK;
	pon_cntl |= (delay & PON_CNTL_TRIG_DELAY_MASK);
	if (pull_up)
		pon_cntl |= PON_CNTL_PULL_UP;
	else
		pon_cntl &= ~PON_CNTL_PULL_UP;

	err = regmap_write(regmap, PON_CNTL_1, pon_cntl);
	if (err < 0) {
		dev_err(&pdev->dev, "failed writing PON_CNTL_1 err=%d\n", err);
		return err;
	}

	err = devm_request_irq(&pdev->dev, key_press_irq, pwrkey_press_irq,
			       IRQF_TRIGGER_RISING,
			       "pmic8xxx_pwrkey_press", pwr);
	if (err) {
		dev_err(&pdev->dev, "Can't get %d IRQ for pwrkey: %d\n",
			key_press_irq, err);
		return err;
	}

	err = devm_request_irq(&pdev->dev, key_release_irq, pwrkey_release_irq,
			       IRQF_TRIGGER_RISING,
			       "pmic8xxx_pwrkey_release", pwr);
	if (err) {
		dev_err(&pdev->dev, "Can't get %d IRQ for pwrkey: %d\n",
			key_release_irq, err);
		return err;
	}

	err = input_register_device(pwr);
	if (err) {
		dev_err(&pdev->dev, "Can't register power key: %d\n", err);
		return err;
	}

	platform_set_drvdata(pdev, pwrkey);
	device_init_wakeup(&pdev->dev, 1);

	return 0;
}

static const struct of_device_id pm8xxx_pwr_key_id_table[] = {
	{ .compatible = "qcom,pm8058-pwrkey", .data = &pm8058_pwrkey_shutdown },
	{ .compatible = "qcom,pm8921-pwrkey", .data = &pm8921_pwrkey_shutdown },
	{ }
};
MODULE_DEVICE_TABLE(of, pm8xxx_pwr_key_id_table);

static struct platform_driver pmic8xxx_pwrkey_driver = {
	.probe		= pmic8xxx_pwrkey_probe,
	.shutdown	= pmic8xxx_pwrkey_shutdown,
	.driver		= {
		.name	= "pm8xxx-pwrkey",
		.pm	= &pm8xxx_pwr_key_pm_ops,
		.of_match_table = pm8xxx_pwr_key_id_table,
	},
};
module_platform_driver(pmic8xxx_pwrkey_driver);

MODULE_ALIAS("platform:pmic8xxx_pwrkey");
MODULE_DESCRIPTION("PMIC8XXX Power Key driver");
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Trilok Soni <tsoni@codeaurora.org>");