[PATCH] gpio: Add support for Intel Crystal Cove PMIC

["Zhu, Lejun" <lejun.zhu@xxxxxxxxxxxxxxx>]

Devices based on Intel SoC products such as Baytrail have a Power
Management IC. In the PMIC there are subsystems for voltage regulation,
A/D conversion, GPIO and PWMs. The PMIC in Baytrail-T platform is
called Crystal Cove.

This patch adds support for the GPIO function in Crystal Cove.

Signed-off-by: Yang, Bin <bin.yang@xxxxxxxxx>
Signed-off-by: Zhu, Lejun <lejun.zhu@xxxxxxxxxxxxxxx>
---
v2:
- Use IRQ chip helper to provide irqdomain.
- Implement .remove and can now build as a module.
- Various fix for unreadable or ugly code pieces.
v3:
- More fix in irq_handler and probe.
v4:
- Minor fix of one return statement.
v5:
- intel_soc_pmic_readb/writeb/setb/clearb are removed from the MFD
  driver, so use regmap_* API here instead.
- Check for unsupported IRQ type and return -EINVAL.
- Create to_cg() and to_reg() inline functions to make the code
  readable.
---
 drivers/gpio/Kconfig            |  13 ++
 drivers/gpio/Makefile           |   1 +
 drivers/gpio/gpio-crystalcove.c | 380 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 394 insertions(+)
 create mode 100644 drivers/gpio/gpio-crystalcove.c

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index a86c49a..fed08d9d 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -440,6 +440,19 @@ config GPIO_ARIZONA
 	help
 	  Support for GPIOs on Wolfson Arizona class devices.
 
+config GPIO_CRYSTAL_COVE
+	tristate "GPIO support for Crystal Cove PMIC"
+	depends on INTEL_SOC_PMIC
+	select GPIOLIB_IRQCHIP
+	help
+	  Support for GPIO pins on Crystal Cove PMIC.
+
+	  Say Yes if you have a Intel SoC based tablet with Crystal Cove PMIC
+	  inside.
+
+	  This driver can also be built as a module. If so, the module will be
+	  called gpio-crystalcove.
+
 config GPIO_LP3943
 	tristate "TI/National Semiconductor LP3943 GPIO expander"
 	depends on MFD_LP3943
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 6309aff..e6cd935 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -20,6 +20,7 @@ obj-$(CONFIG_GPIO_BCM_KONA)	+= gpio-bcm-kona.o
 obj-$(CONFIG_GPIO_BT8XX)	+= gpio-bt8xx.o
 obj-$(CONFIG_GPIO_CLPS711X)	+= gpio-clps711x.o
 obj-$(CONFIG_GPIO_CS5535)	+= gpio-cs5535.o
+obj-$(CONFIG_GPIO_CRYSTAL_COVE)	+= gpio-crystalcove.o
 obj-$(CONFIG_GPIO_DA9052)	+= gpio-da9052.o
 obj-$(CONFIG_GPIO_DA9055)	+= gpio-da9055.o
 obj-$(CONFIG_GPIO_DAVINCI)	+= gpio-davinci.o
diff --git a/drivers/gpio/gpio-crystalcove.c b/drivers/gpio/gpio-crystalcove.c
new file mode 100644
index 0000000..b8ed0c6
--- /dev/null
+++ b/drivers/gpio/gpio-crystalcove.c
@@ -0,0 +1,380 @@
+/*
+ * gpio-crystalcove.c - Intel Crystal Cove GPIO Driver
+ *
+ * Copyright (C) 2012, 2014 Intel Corporation. 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 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.
+ *
+ * Author: Yang, Bin <bin.yang@xxxxxxxxx>
+ */
+
+#include <linux/interrupt.h>
+#include <linux/platform_device.h>
+#include <linux/gpio.h>
+#include <linux/bitops.h>
+#include <linux/regmap.h>
+#include <linux/mfd/intel_soc_pmic.h>
+
+#define NUM_GPIO		16
+
+#define UPDATE_IRQ_TYPE		BIT(0)
+#define UPDATE_IRQ_MASK		BIT(1)
+
+#define GPIO0IRQ		0x0b
+#define GPIO1IRQ		0x0c
+#define MGPIO0IRQS0		0x19
+#define MGPIO1IRQS0		0x1a
+#define MGPIO0IRQSX		0x1b
+#define MGPIO1IRQSX		0x1c
+#define GPIO0P0CTLO		0x2b
+#define GPIO0P0CTLI		0x33
+#define GPIO1P0CTLO		0x3b
+#define GPIO1P0CTLI		0x43
+
+#define CTLI_INTCNT_DIS		(0)
+#define CTLI_INTCNT_NE		(1 << 1)
+#define CTLI_INTCNT_PE		(2 << 1)
+#define CTLI_INTCNT_BE		(3 << 1)
+
+#define CTLO_DIR_IN		(0)
+#define CTLO_DIR_OUT		(1 << 5)
+
+#define CTLO_DRV_CMOS		(0)
+#define CTLO_DRV_OD		(1 << 4)
+
+#define CTLO_DRV_REN		(1 << 3)
+
+#define CTLO_RVAL_2KDW		(0)
+#define CTLO_RVAL_2KUP		(1 << 1)
+#define CTLO_RVAL_50KDW		(2 << 1)
+#define CTLO_RVAL_50KUP		(3 << 1)
+
+#define CTLO_INPUT_SET	(CTLO_DRV_CMOS | CTLO_DRV_REN | CTLO_RVAL_2KUP)
+#define CTLO_OUTPUT_SET	(CTLO_DIR_OUT | CTLO_INPUT_SET)
+
+enum ctrl_register {
+	CTRL_IN,
+	CTRL_OUT,
+};
+
+/**
+ * struct crystalcove_gpio - Crystal Cove GPIO controller
+ * @buslock: for bus lock/sync and unlock.
+ * @chip: the abstract gpio_chip structure.
+ * @regmap: the regmap from the parent device.
+ * @update: pending IRQ setting update, to be written to the chip upon unlock.
+ * @intcnt_value: the Interrupt Detect value to be written.
+ * @set_irq_mask: true if the IRQ mask needs to be set, false to clear.
+ */
+struct crystalcove_gpio {
+	struct mutex buslock; /* irq_bus_lock */
+	struct gpio_chip chip;
+	struct regmap *regmap;
+	int update;
+	int intcnt_value;
+	bool set_irq_mask;
+};
+
+static inline struct crystalcove_gpio *to_cg(struct gpio_chip *gc)
+{
+	return container_of(gc, struct crystalcove_gpio, chip);
+}
+
+static inline int to_reg(int gpio, enum ctrl_register reg_type)
+{
+	int reg;
+
+	if (reg_type == CTRL_IN) {
+		if (gpio < 8)
+			reg = GPIO0P0CTLI;
+		else
+			reg = GPIO1P0CTLI;
+	} else {
+		if (gpio < 8)
+			reg = GPIO0P0CTLO;
+		else
+			reg = GPIO1P0CTLO;
+	}
+
+	return reg + gpio % 8;
+}
+
+static void crystalcove_update_irq_mask(struct crystalcove_gpio *cg,
+					int gpio)
+{
+	u8 mirqs0 = gpio < 8 ? MGPIO0IRQS0 : MGPIO1IRQS0;
+	int mask = BIT(gpio % 8);
+
+	if (cg->set_irq_mask)
+		regmap_update_bits(cg->regmap, mirqs0, mask, mask);
+	else
+		regmap_update_bits(cg->regmap, mirqs0, mask, 0);
+}
+
+static void crystalcove_update_irq_ctrl(struct crystalcove_gpio *cg, int gpio)
+{
+	int reg = to_reg(gpio, CTRL_IN);
+
+	regmap_update_bits(cg->regmap, reg, CTLI_INTCNT_BE, cg->intcnt_value);
+}
+
+static int crystalcove_gpio_dir_in(struct gpio_chip *chip, unsigned gpio)
+{
+	struct crystalcove_gpio *cg = to_cg(chip);
+
+	return regmap_write(cg->regmap, to_reg(gpio, CTRL_OUT),
+			    CTLO_INPUT_SET);
+}
+
+static int crystalcove_gpio_dir_out(struct gpio_chip *chip, unsigned gpio,
+				    int value)
+{
+	struct crystalcove_gpio *cg = to_cg(chip);
+
+	return regmap_write(cg->regmap, to_reg(gpio, CTRL_OUT),
+			    CTLO_OUTPUT_SET | value);
+}
+
+static int crystalcove_gpio_get(struct gpio_chip *chip, unsigned gpio)
+{
+	struct crystalcove_gpio *cg = to_cg(chip);
+	int ret;
+	unsigned int val;
+
+	ret = regmap_read(cg->regmap, to_reg(gpio, CTRL_IN), &val);
+	if (ret)
+		return ret;
+
+	return val & 0x1;
+}
+
+static void crystalcove_gpio_set(struct gpio_chip *chip,
+				 unsigned gpio, int value)
+{
+	struct crystalcove_gpio *cg = to_cg(chip);
+
+	if (value)
+		regmap_update_bits(cg->regmap, to_reg(gpio, CTRL_OUT), 1, 1);
+	else
+		regmap_update_bits(cg->regmap, to_reg(gpio, CTRL_OUT), 1, 0);
+}
+
+static int crystalcove_irq_type(struct irq_data *data, unsigned type)
+{
+	struct crystalcove_gpio *cg = to_cg(irq_data_get_irq_chip_data(data));
+
+	switch (type) {
+	case IRQ_TYPE_NONE:
+		cg->intcnt_value = CTLI_INTCNT_DIS;
+		break;
+	case IRQ_TYPE_EDGE_BOTH:
+		cg->intcnt_value = CTLI_INTCNT_BE;
+		break;
+	case IRQ_TYPE_EDGE_RISING:
+		cg->intcnt_value = CTLI_INTCNT_PE;
+		break;
+	case IRQ_TYPE_EDGE_FALLING:
+		cg->intcnt_value = CTLI_INTCNT_NE;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	cg->update |= UPDATE_IRQ_TYPE;
+
+	return 0;
+}
+
+static void crystalcove_bus_lock(struct irq_data *data)
+{
+	struct crystalcove_gpio *cg = to_cg(irq_data_get_irq_chip_data(data));
+
+	mutex_lock(&cg->buslock);
+}
+
+static void crystalcove_bus_sync_unlock(struct irq_data *data)
+{
+	struct crystalcove_gpio *cg = to_cg(irq_data_get_irq_chip_data(data));
+	int gpio = data->hwirq;
+
+	if (cg->update & UPDATE_IRQ_TYPE)
+		crystalcove_update_irq_ctrl(cg, gpio);
+	if (cg->update & UPDATE_IRQ_MASK)
+		crystalcove_update_irq_mask(cg, gpio);
+	cg->update = 0;
+
+	mutex_unlock(&cg->buslock);
+}
+
+static void crystalcove_irq_unmask(struct irq_data *data)
+{
+	struct crystalcove_gpio *cg = to_cg(irq_data_get_irq_chip_data(data));
+
+	cg->set_irq_mask = false;
+	cg->update |= UPDATE_IRQ_MASK;
+}
+
+static void crystalcove_irq_mask(struct irq_data *data)
+{
+	struct crystalcove_gpio *cg = to_cg(irq_data_get_irq_chip_data(data));
+
+	cg->set_irq_mask = true;
+	cg->update |= UPDATE_IRQ_MASK;
+}
+
+static struct irq_chip crystalcove_irqchip = {
+	.name			= "Crystal Cove",
+	.irq_mask		= crystalcove_irq_mask,
+	.irq_unmask		= crystalcove_irq_unmask,
+	.irq_set_type		= crystalcove_irq_type,
+	.irq_bus_lock		= crystalcove_bus_lock,
+	.irq_bus_sync_unlock	= crystalcove_bus_sync_unlock,
+};
+
+static irqreturn_t crystalcove_gpio_irq_handler(int irq, void *data)
+{
+	struct crystalcove_gpio *cg = data;
+	unsigned int p0, p1;
+	int pending;
+	int gpio;
+	unsigned int virq;
+
+	if (regmap_read(cg->regmap, GPIO0IRQ, &p0) ||
+	    regmap_read(cg->regmap, GPIO1IRQ, &p1))
+		return IRQ_NONE;
+
+	regmap_write(cg->regmap, GPIO0IRQ, p0);
+	regmap_write(cg->regmap, GPIO1IRQ, p1);
+
+	pending = p0 | p1 << 8;
+
+	for (gpio = 0; gpio < cg->chip.ngpio; gpio++) {
+		if (pending & BIT(gpio)) {
+			virq = irq_find_mapping(cg->chip.irqdomain, gpio);
+			generic_handle_irq(virq);
+		}
+	}
+
+	return IRQ_HANDLED;
+}
+
+static void crystalcove_gpio_dbg_show(struct seq_file *s,
+				      struct gpio_chip *chip)
+{
+	struct crystalcove_gpio *cg = to_cg(chip);
+	int gpio, offset;
+	unsigned int ctlo, ctli, mirqs0, mirqsx, irq;
+
+	for (gpio = 0; gpio < cg->chip.ngpio; gpio++) {
+		regmap_read(cg->regmap, to_reg(gpio, CTRL_OUT), &ctlo);
+		regmap_read(cg->regmap, to_reg(gpio, CTRL_IN), &ctli);
+		regmap_read(cg->regmap, gpio < 8 ? MGPIO0IRQS0 : MGPIO1IRQS0,
+			    &mirqs0);
+		regmap_read(cg->regmap, gpio < 8 ? MGPIO0IRQSX : MGPIO1IRQSX,
+			    &mirqsx);
+		regmap_read(cg->regmap, gpio < 8 ? GPIO0IRQ : GPIO1IRQ,
+			    &irq);
+
+		offset = gpio % 8;
+		seq_printf(s, " gpio-%-2d %s %s %s %s ctlo=%2x,%s %s %s\n",
+			   gpio, ctlo & CTLO_DIR_OUT ? "out" : "in ",
+			   ctli & 0x1 ? "hi" : "lo",
+			   ctli & CTLI_INTCNT_NE ? "fall" : "    ",
+			   ctli & CTLI_INTCNT_PE ? "rise" : "    ",
+			   ctlo,
+			   mirqs0 & BIT(offset) ? "s0 mask  " : "s0 unmask",
+			   mirqsx & BIT(offset) ? "sx mask  " : "sx unmask",
+			   irq & BIT(offset) ? "pending" : "       ");
+	}
+}
+
+static int crystalcove_gpio_probe(struct platform_device *pdev)
+{
+	int irq = platform_get_irq(pdev, 0);
+	struct crystalcove_gpio *cg;
+	int retval;
+	struct device *dev = pdev->dev.parent;
+	struct intel_soc_pmic *pmic = dev_get_drvdata(dev);
+
+	if (irq < 0)
+		return irq;
+
+	cg = devm_kzalloc(&pdev->dev, sizeof(*cg), GFP_KERNEL);
+	if (!cg)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, cg);
+
+	mutex_init(&cg->buslock);
+	cg->chip.label = KBUILD_MODNAME;
+	cg->chip.direction_input = crystalcove_gpio_dir_in;
+	cg->chip.direction_output = crystalcove_gpio_dir_out;
+	cg->chip.get = crystalcove_gpio_get;
+	cg->chip.set = crystalcove_gpio_set;
+	cg->chip.base = -1;
+	cg->chip.ngpio = NUM_GPIO;
+	cg->chip.can_sleep = true;
+	cg->chip.dev = dev;
+	cg->chip.dbg_show = crystalcove_gpio_dbg_show;
+	cg->regmap = pmic->regmap;
+
+	gpiochip_irqchip_add(&cg->chip, &crystalcove_irqchip, 0,
+			     handle_simple_irq, IRQ_TYPE_NONE);
+
+	retval = request_threaded_irq(irq, NULL, crystalcove_gpio_irq_handler,
+				      IRQF_ONESHOT, KBUILD_MODNAME, cg);
+
+	if (retval) {
+		dev_warn(&pdev->dev, "request irq failed: %d\n", retval);
+		goto out;
+	}
+
+	retval = gpiochip_add(&cg->chip);
+	if (retval) {
+		dev_warn(&pdev->dev, "add gpio chip error: %d\n", retval);
+		goto out_free_irq;
+	}
+
+	return 0;
+
+out_free_irq:
+	free_irq(irq, cg);
+out:
+	return retval;
+}
+
+static int crystalcove_gpio_remove(struct platform_device *pdev)
+{
+	struct crystalcove_gpio *cg = platform_get_drvdata(pdev);
+	int irq = platform_get_irq(pdev, 0);
+	int err;
+
+	err = gpiochip_remove(&cg->chip);
+
+	if (irq >= 0)
+		free_irq(irq, cg);
+
+	return err;
+}
+
+static struct platform_driver crystalcove_gpio_driver = {
+	.probe = crystalcove_gpio_probe,
+	.remove = crystalcove_gpio_remove,
+	.driver = {
+		.name = "crystal_cove_gpio",
+		.owner = THIS_MODULE,
+	},
+};
+
+module_platform_driver(crystalcove_gpio_driver);
+
+MODULE_AUTHOR("Yang, Bin <bin.yang@xxxxxxxxx>");
+MODULE_DESCRIPTION("Intel Crystal Cove GPIO Driver");
+MODULE_LICENSE("GPL v2");
-- 
1.8.3.2

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