Date:   Mon, 28 Sep 2020 15:19:43 +0800
From:   cy_huang <u0084500@...il.com>
To:     lgirdwood@...il.com, broonie@...nel.org, robh+dt@...nel.org
Cc:     linux-kernel@...r.kernel.org, cy_huang@...htek.com,
        devicetree@...r.kernel.org
Subject: [PATCH v2 1/2] regulator: rtmv20: Adds support for Richtek RTMV20 load switch regulator

From: ChiYuan Huang <cy_huang@...htek.com>

Add support for Richtek RTMV20 load switch regulator.

Signed-off-by: ChiYuan Huang <cy_huang@...htek.com>
---
v1 to v2
1. Use regcache related APIs when HW disable and enable.
2. Because of regcache, refine the initial properties flow.
3. Change all propertiy name to use dash, not underline.
4. Re-check all the comment lines not to over 80 characters.
5. Same as item 3, and also change all 0/1 properties to boolean type in
   dt-binding document.
6. No need is_chip_enabled flag.

---
 drivers/regulator/Kconfig            |   9 +
 drivers/regulator/Makefile           |   1 +
 drivers/regulator/rtmv20-regulator.c | 392 +++++++++++++++++++++++++++++++++++
 3 files changed, 402 insertions(+)
 create mode 100644 drivers/regulator/rtmv20-regulator.c

diff --git a/drivers/regulator/Kconfig b/drivers/regulator/Kconfig
index de17ef7..400ad4c 100644
--- a/drivers/regulator/Kconfig
+++ b/drivers/regulator/Kconfig
@@ -902,6 +902,15 @@ config REGULATOR_RT5033
 	  RT5033 PMIC. The device supports multiple regulators like
 	  current source, LDO and Buck.
 
+config REGULATOR_RTMV20
+	tristate "RTMV20 Laser Diode Regulator"
+	depends on I2C
+	select REGMAP_I2C
+	help
+	  This driver adds support for the load switch current regulator on
+	  the Richtek RTMV20. It can support the load current up to 6A and
+	  integrate strobe/vsync/fsin signal to synchronize the IR camera.
+
 config REGULATOR_S2MPA01
 	tristate "Samsung S2MPA01 voltage regulator"
 	depends on MFD_SEC_CORE
diff --git a/drivers/regulator/Makefile b/drivers/regulator/Makefile
index d8d3ecf..89a1cb0 100644
--- a/drivers/regulator/Makefile
+++ b/drivers/regulator/Makefile
@@ -112,6 +112,7 @@ obj-$(CONFIG_REGULATOR_RK808)   += rk808-regulator.o
 obj-$(CONFIG_REGULATOR_RN5T618) += rn5t618-regulator.o
 obj-$(CONFIG_REGULATOR_ROHM)	+= rohm-regulator.o
 obj-$(CONFIG_REGULATOR_RT5033)	+= rt5033-regulator.o
+obj-$(CONFIG_REGULATOR_RTMV20)	+= rtmv20-regulator.o
 obj-$(CONFIG_REGULATOR_S2MPA01) += s2mpa01.o
 obj-$(CONFIG_REGULATOR_S2MPS11) += s2mps11.o
 obj-$(CONFIG_REGULATOR_S5M8767) += s5m8767.o
diff --git a/drivers/regulator/rtmv20-regulator.c b/drivers/regulator/rtmv20-regulator.c
new file mode 100644
index 00000000..1075b10
--- /dev/null
+++ b/drivers/regulator/rtmv20-regulator.c
@@ -0,0 +1,392 @@
+// SPDX-License-Identifier: GPL-2.0+
+
+#include <linux/delay.h>
+#include <linux/gpio/consumer.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/property.h>
+#include <linux/regmap.h>
+#include <linux/regulator/driver.h>
+
+#define RTMV20_REG_DEVINFO	0x00
+#define RTMV20_REG_PULSEDELAY	0x01
+#define RTMV20_REG_PULSEWIDTH	0x03
+#define RTMV20_REG_LDCTRL1	0x05
+#define RTMV20_REG_ESPULSEWIDTH	0x06
+#define RTMV20_REG_ESLDCTRL1	0x08
+#define RTMV20_REG_LBP		0x0A
+#define RTMV20_REG_LDCTRL2	0x0B
+#define RTMV20_REG_FSIN1CTRL1	0x0D
+#define RTMV20_REG_FSIN1CTRL3	0x0F
+#define RTMV20_REG_FSIN2CTRL1	0x10
+#define RTMV20_REG_FSIN2CTRL3	0x12
+#define RTMV20_REG_ENCTRL	0x13
+#define RTMV20_REG_STRBVSYNDLYL 0x29
+#define RTMV20_REG_LDIRQ	0x30
+#define RTMV20_REG_LDSTAT	0x40
+#define RTMV20_REG_LDMASK	0x50
+
+#define RTMV20_VID_MASK		GENMASK(7, 4)
+#define RICHTEK_VID		0x80
+#define RTMV20_LDCURR_MASK	GENMASK(7, 0)
+#define RTMV20_DELAY_MASK	GENMASK(9, 0)
+#define RTMV20_WIDTH_MASK	GENMASK(13, 0)
+#define RTMV20_WIDTH2_MASK	GENMASK(7, 0)
+#define RTMV20_LBPLVL_MASK	GENMASK(3, 0)
+#define RTMV20_LBPEN_MASK	BIT(7)
+#define RTMV20_STROBEPOL_MASK	BIT(1)
+#define RTMV20_VSYNPOL_MASK	BIT(1)
+#define RTMV20_FSINEN_MASK	BIT(7)
+#define RTMV20_ESEN_MASK	BIT(6)
+#define RTMV20_FSINOUT_MASK	BIT(2)
+#define LDENABLE_MASK		(BIT(3) | BIT(0))
+
+#define OTPEVT_MASK		BIT(4)
+#define SHORTEVT_MASK		BIT(3)
+#define OPENEVT_MASK		BIT(2)
+#define LBPEVT_MASK		BIT(1)
+#define OCPEVT_MASK		BIT(0)
+#define FAILEVT_MASK		(SHORTEVT_MASK | OPENEVT_MASK | LBPEVT_MASK)
+
+#define RTMV20_LSW_MINUA	0
+#define RTMV20_LSW_MAXUA	6000000
+#define RTMV20_LSW_STEPUA	30000
+
+#define RTMV20_LSW_DEFAULTUA	3000000
+
+#define RTMV20_I2CRDY_TIMEUS	200
+#define RTMV20_CSRDY_TIMEUS	2000
+
+struct rtmv20_priv {
+	struct device *dev;
+	struct regmap *regmap;
+	struct gpio_desc *enable_gpio;
+	struct regulator_dev *rdev;
+};
+
+static int rtmv20_lsw_enable(struct regulator_dev *rdev)
+{
+	struct rtmv20_priv *priv = rdev_get_drvdata(rdev);
+	int ret;
+
+	gpiod_set_value(priv->enable_gpio, 1);
+
+	/* Wait for I2C can be accessed */
+	usleep_range(RTMV20_I2CRDY_TIMEUS, RTMV20_I2CRDY_TIMEUS + 100);
+
+	/* HW re-enable, disable cache only and sync regcache here */
+	regcache_cache_only(priv->regmap, false);
+	ret = regcache_sync(priv->regmap);
+	if (ret)
+		return ret;
+
+	return regulator_enable_regmap(rdev);
+}
+
+static int rtmv20_lsw_disable(struct regulator_dev *rdev)
+{
+	struct rtmv20_priv *priv = rdev_get_drvdata(rdev);
+	int ret;
+
+	ret = regulator_disable_regmap(rdev);
+	if (ret)
+		return ret;
+
+	/* Mark the regcache as dirty and cache only before HW disabled */
+	regcache_cache_only(priv->regmap, true);
+	regcache_mark_dirty(priv->regmap);
+
+	gpiod_set_value(priv->enable_gpio, 0);
+
+	return 0;
+}
+
+static const struct regulator_ops rtmv20_regulator_ops = {
+	.set_current_limit = regulator_set_current_limit_regmap,
+	.get_current_limit = regulator_get_current_limit_regmap,
+	.enable = rtmv20_lsw_enable,
+	.disable = rtmv20_lsw_disable,
+	.is_enabled = regulator_is_enabled_regmap,
+};
+
+static const struct regulator_desc rtmv20_lsw_desc = {
+	.name = "rtmv20,lsw",
+	.of_match = of_match_ptr("lsw"),
+	.type = REGULATOR_CURRENT,
+	.owner = THIS_MODULE,
+	.ops = &rtmv20_regulator_ops,
+	.csel_reg = RTMV20_REG_LDCTRL1,
+	.csel_mask = RTMV20_LDCURR_MASK,
+	.enable_reg = RTMV20_REG_ENCTRL,
+	.enable_mask = LDENABLE_MASK,
+	.enable_time = RTMV20_CSRDY_TIMEUS,
+};
+
+static irqreturn_t rtmv20_irq_handler(int irq, void *data)
+{
+	struct rtmv20_priv *priv = data;
+	unsigned int val;
+	int ret;
+
+	ret = regmap_read(priv->regmap, RTMV20_REG_LDIRQ, &val);
+	if (ret) {
+		dev_err(priv->dev, "Failed to get irq flags\n");
+		return IRQ_NONE;
+	}
+
+	if (val & OTPEVT_MASK)
+		regulator_notifier_call_chain(priv->rdev, REGULATOR_EVENT_OVER_TEMP, NULL);
+
+	if (val & OCPEVT_MASK)
+		regulator_notifier_call_chain(priv->rdev, REGULATOR_EVENT_OVER_CURRENT, NULL);
+
+	if (val & FAILEVT_MASK)
+		regulator_notifier_call_chain(priv->rdev, REGULATOR_EVENT_FAIL, NULL);
+
+	return IRQ_HANDLED;
+}
+
+static u32 clamp_to_selector(u32 val, u32 min, u32 max, u32 step)
+{
+	u32 retval = clamp_val(val, min, max);
+
+	return (retval - min) / step;
+}
+
+static int rtmv20_properties_init(struct rtmv20_priv *priv)
+{
+	const struct {
+		const char *name;
+		u32 def;
+		u32 min;
+		u32 max;
+		u32 step;
+		u32 addr;
+		u32 mask;
+	} props[] = {
+		{ "ld-pulse-delay-us", 0, 0, 100000, 100, RTMV20_REG_PULSEDELAY,
+			RTMV20_DELAY_MASK },
+		{ "ld-pulse-width-us", 1200, 0, 10000, 1, RTMV20_REG_PULSEWIDTH,
+			RTMV20_WIDTH_MASK },
+		{ "fsin1-delay-us", 23000, 0, 100000, 100, RTMV20_REG_FSIN1CTRL1,
+			RTMV20_DELAY_MASK },
+		{ "fsin1-width-us", 160, 40, 10000, 40, RTMV20_REG_FSIN1CTRL3, RTMV20_WIDTH2_MASK },
+		{ "fsin2-delay-us", 23000, 0, 100000, 100, RTMV20_REG_FSIN2CTRL1,
+			RTMV20_DELAY_MASK },
+		{ "fsin2-width-us", 160, 40, 10000, 40, RTMV20_REG_FSIN2CTRL3, RTMV20_WIDTH2_MASK },
+		{ "es-pulse-width-us", 1200, 0, 10000, 1, RTMV20_REG_ESPULSEWIDTH,
+			RTMV20_WIDTH_MASK },
+		{ "es-ld-current-microamp", 3000000, 0, 6000000, 30000, RTMV20_REG_ESLDCTRL1,
+			RTMV20_LDCURR_MASK },
+		{ "lbp-level-microvolt", 2700000, 2400000, 3700000, 100000, RTMV20_REG_LBP,
+			RTMV20_LBPLVL_MASK },
+		{ "lbp-enable", 0, 0, 1, 1, RTMV20_REG_LBP, RTMV20_LBPEN_MASK },
+		{ "strobe-polarity-high", 1, 0, 1, 1, RTMV20_REG_LDCTRL2, RTMV20_STROBEPOL_MASK },
+		{ "vsync-polarity-high", 1, 0, 1, 1, RTMV20_REG_LDCTRL2, RTMV20_VSYNPOL_MASK },
+		{ "fsin-enable", 0, 0, 1, 1, RTMV20_REG_ENCTRL, RTMV20_FSINEN_MASK },
+		{ "fsin-output", 0, 0, 1, 1, RTMV20_REG_ENCTRL, RTMV20_FSINOUT_MASK },
+		{ "es-enable", 0, 0, 1, 1, RTMV20_REG_ENCTRL, RTMV20_ESEN_MASK },
+	};
+	int i, ret;
+
+	for (i = 0; i < ARRAY_SIZE(props); i++) {
+		__be16 bval16;
+		u16 val16;
+		u32 temp;
+		int significant_bit = fls(props[i].mask);
+		int shift = ffs(props[i].mask) - 1;
+
+		if (props[i].max > 1) {
+			ret = device_property_read_u32(priv->dev, props[i].name, &temp);
+			if (ret)
+				temp = props[i].def;
+		} else
+			temp = device_property_read_bool(priv->dev, props[i].name);
+
+		temp = clamp_to_selector(temp, props[i].min, props[i].max, props[i].step);
+
+		/* If significant bit is over 8, two byte access, others one */
+		if (significant_bit > 8) {
+			ret = regmap_raw_read(priv->regmap, props[i].addr, &bval16, sizeof(bval16));
+			if (ret)
+				return ret;
+
+			val16 = be16_to_cpu(bval16);
+			val16 &= ~props[i].mask;
+			val16 |= (temp << shift);
+			bval16 = cpu_to_be16(val16);
+
+			ret = regmap_raw_write(priv->regmap, props[i].addr, &bval16,
+					       sizeof(bval16));
+		} else {
+			ret = regmap_update_bits(priv->regmap, props[i].addr, props[i].mask,
+						 temp << shift);
+		}
+
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int rtmv20_check_chip_exist(struct rtmv20_priv *priv)
+{
+	unsigned int val;
+	int ret;
+
+	ret = regmap_read(priv->regmap, RTMV20_REG_DEVINFO, &val);
+	if (ret)
+		return ret;
+
+	if ((val & RTMV20_VID_MASK) != RICHTEK_VID)
+		return -ENODEV;
+
+	return 0;
+}
+
+static bool rtmv20_is_accessible_reg(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case RTMV20_REG_DEVINFO ... RTMV20_REG_STRBVSYNDLYL:
+	case RTMV20_REG_LDIRQ:
+	case RTMV20_REG_LDSTAT:
+	case RTMV20_REG_LDMASK:
+		return true;
+	}
+	return false;
+}
+
+static bool rtmv20_is_volatile_reg(struct device *dev, unsigned int reg)
+{
+	if (reg == RTMV20_REG_LDIRQ || reg == RTMV20_REG_LDSTAT)
+		return true;
+	return false;
+}
+
+static const struct regmap_config rtmv20_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.cache_type = REGCACHE_RBTREE,
+	.max_register = RTMV20_REG_LDMASK,
+
+	.writeable_reg = rtmv20_is_accessible_reg,
+	.readable_reg = rtmv20_is_accessible_reg,
+	.volatile_reg = rtmv20_is_volatile_reg,
+};
+
+static int rtmv20_probe(struct i2c_client *i2c)
+{
+	struct rtmv20_priv *priv;
+	struct regulator_config config = {};
+	int ret;
+
+	priv = devm_kzalloc(&i2c->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->dev = &i2c->dev;
+
+	/* Before regmap register, configure HW enable to make I2C accessible */
+	priv->enable_gpio = devm_gpiod_get(&i2c->dev, "enable", GPIOD_OUT_HIGH);
+	if (IS_ERR(priv->enable_gpio)) {
+		dev_err(&i2c->dev, "Failed to get enable gpio\n");
+		return PTR_ERR(priv->enable_gpio);
+	}
+
+	/* Wait for I2C can be accessed */
+	usleep_range(RTMV20_I2CRDY_TIMEUS, RTMV20_I2CRDY_TIMEUS + 100);
+
+	priv->regmap = devm_regmap_init_i2c(i2c, &rtmv20_regmap_config);
+	if (IS_ERR(priv->regmap)) {
+		dev_err(&i2c->dev, "Failed to allocate register map\n");
+		return PTR_ERR(priv->regmap);
+	}
+
+	ret = rtmv20_check_chip_exist(priv);
+	if (ret) {
+		dev_err(&i2c->dev, "Chip vendor info is not matched\n");
+		return ret;
+	}
+
+	ret = rtmv20_properties_init(priv);
+	if (ret) {
+		dev_err(&i2c->dev, "Failed to init properties\n");
+		return ret;
+	}
+
+	/*
+	 * keep in shutdown mode to minimize the current consumption
+	 * and also mark regcache as dirty
+	 */
+	regcache_mark_dirty(priv->regmap);
+	gpiod_set_value(priv->enable_gpio, 0);
+
+	config.dev = &i2c->dev;
+	config.regmap = priv->regmap;
+	config.driver_data = priv;
+	priv->rdev = devm_regulator_register(&i2c->dev, &rtmv20_lsw_desc, &config);
+	if (IS_ERR(priv->rdev)) {
+		dev_err(&i2c->dev, "Failed to register regulator\n");
+		return PTR_ERR(priv->rdev);
+	}
+
+	/* Unmask all events before IRQ registered */
+	ret = regmap_write(priv->regmap, RTMV20_REG_LDMASK, 0);
+	if (ret)
+		return ret;
+
+	return devm_request_threaded_irq(&i2c->dev, i2c->irq, NULL, rtmv20_irq_handler,
+					 IRQF_ONESHOT, dev_name(&i2c->dev), priv);
+}
+
+static int __maybe_unused rtmv20_suspend(struct device *dev)
+{
+	struct i2c_client *i2c = to_i2c_client(dev);
+
+	/*
+	 * When system suspend, disable irq to prevent interrupt trigger
+	 * during I2C bus suspend
+	 */
+	disable_irq(i2c->irq);
+	if (device_may_wakeup(dev))
+		enable_irq_wake(i2c->irq);
+
+	return 0;
+}
+
+static int __maybe_unused rtmv20_resume(struct device *dev)
+{
+	struct i2c_client *i2c = to_i2c_client(dev);
+
+	/* Enable irq after I2C bus already resume */
+	enable_irq(i2c->irq);
+	if (device_may_wakeup(dev))
+		disable_irq_wake(i2c->irq);
+
+	return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(rtmv20_pm, rtmv20_suspend, rtmv20_resume);
+
+static const struct of_device_id __maybe_unused rtmv20_of_id[] = {
+	{ .compatible = "richtek,rtmv20", },
+	{}
+};
+MODULE_DEVICE_TABLE(of, rtmv20_of_id);
+
+static struct i2c_driver rtmv20_driver = {
+	.driver = {
+		.name = "rtmv20",
+		.of_match_table = of_match_ptr(rtmv20_of_id),
+		.pm = &rtmv20_pm,
+	},
+	.probe_new = rtmv20_probe,
+};
+module_i2c_driver(rtmv20_driver);
+
+MODULE_AUTHOR("ChiYuan Huang <cy_huang@...htek.com>");
+MODULE_DESCRIPTION("Richtek RTMV20 Regulator Driver");
+MODULE_LICENSE("GPL v2");
-- 
2.7.4

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