[PATCH v2] gpio: Add support for Intel SoC PMIC (Crystal Cove)

["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.

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.

Signed-off-by: Yang, Bin <bin.yang@xxxxxxxxx>
Signed-off-by: Zhu, Lejun <lejun.zhu@xxxxxxxxxxxxxxx>
---
 drivers/gpio/Kconfig            |  13 ++
 drivers/gpio/Makefile           |   1 +
 drivers/gpio/gpio-crystalcove.c | 344 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 358 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..49d9c52
--- /dev/null
+++ b/drivers/gpio/gpio-crystalcove.c
@@ -0,0 +1,344 @@
+/*
+ * 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/module.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/io.h>
+#include <linux/delay.h>
+#include <linux/interrupt.h>
+#include <linux/device.h>
+#include <linux/platform_device.h>
+#include <linux/seq_file.h>
+#include <linux/sched.h>
+#include <linux/mfd/intel_soc_pmic.h>
+#include <linux/gpio.h>
+#include <linux/bitops.h>
+
+#define NUM_GPIO		16
+
+#define UPDATE_TYPE		BIT(0)
+#define UPDATE_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_NE		(1 << 1)
+#define CTLI_INTCNT_PE		(2 << 1)
+#define CTLI_INTCNT_BE		(3 << 1)
+
+#define CTLO_DIR_OUT		(1 << 5)
+
+#define CTLO_DRV_CMOS		(0 << 4)
+#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_DEF	(CTLO_DRV_CMOS | CTLO_DRV_REN | CTLO_RVAL_2KUP)
+#define CTLO_OUTPUT_DEF	(CTLO_DIR_OUT | CTLO_INPUT_DEF)
+
+#define GPIO_TO_CTL(gpio, dir)		\
+	((gpio < 8 ? GPIO0P0CTL ## dir : GPIO1P0CTL ## dir) + (gpio % 8))
+
+/**
+ * struct crystalcove_gpio - Crystal Cove GPIO controller
+ * @buslock: for bus lock/sync and unlock.
+ * @chip: the abstract gpio_chip structure.
+ * @update: pending IRQ setting update, to be written to the chip upon unlock.
+ * @trigger_type: the trigger type of the IRQ.
+ * @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;
+	int			update;
+	int			trigger_type;
+	bool			set_irq_mask;
+};
+
+static void crystalcove_update_irq_mask(int gpio, bool mask)
+{
+	u8 mirqs0 = gpio < 8 ? MGPIO0IRQS0 : MGPIO1IRQS0;
+	int offset = gpio % 8;
+
+	if (mask)
+		intel_soc_pmic_setb(mirqs0, BIT(offset));
+	else
+		intel_soc_pmic_clearb(mirqs0, BIT(offset));
+}
+
+static void crystalcove_update_irq_type(int gpio, int type)
+{
+	u8 ctli = GPIO_TO_CTL(gpio, I);
+
+	type &= IRQ_TYPE_EDGE_BOTH;
+	intel_soc_pmic_clearb(ctli, CTLI_INTCNT_BE);
+
+	if (type == IRQ_TYPE_EDGE_BOTH)
+		intel_soc_pmic_setb(ctli, CTLI_INTCNT_BE);
+	else if (type == IRQ_TYPE_EDGE_RISING)
+		intel_soc_pmic_setb(ctli, CTLI_INTCNT_PE);
+	else if (type & IRQ_TYPE_EDGE_FALLING)
+		intel_soc_pmic_setb(ctli, CTLI_INTCNT_NE);
+}
+
+static int crystalcove_gpio_direction_input(struct gpio_chip *chip,
+					    unsigned gpio)
+{
+	u8 ctlo = GPIO_TO_CTL(gpio, O);
+
+	intel_soc_pmic_writeb(ctlo, CTLO_INPUT_DEF);
+	return 0;
+}
+
+static int crystalcove_gpio_direction_output(struct gpio_chip *chip,
+					     unsigned gpio, int value)
+{
+	u8 ctlo = GPIO_TO_CTL(gpio, O);
+
+	intel_soc_pmic_writeb(ctlo, CTLO_OUTPUT_DEF | value);
+	return 0;
+}
+
+static int crystalcove_gpio_get(struct gpio_chip *chip, unsigned gpio)
+{
+	u8 ctli = GPIO_TO_CTL(gpio, I);
+
+	return intel_soc_pmic_readb(ctli) & 0x1;
+}
+
+static void crystalcove_gpio_set(struct gpio_chip *chip,
+				 unsigned gpio, int value)
+{
+	u8 ctlo = GPIO_TO_CTL(gpio, O);
+
+	if (value)
+		intel_soc_pmic_setb(ctlo, 1);
+	else
+		intel_soc_pmic_clearb(ctlo, 1);
+}
+
+static int crystalcove_irq_type(struct irq_data *data, unsigned type)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(data);
+	struct crystalcove_gpio *cg =
+		container_of(gc, struct crystalcove_gpio, chip);
+
+	cg->trigger_type = type;
+	cg->update |= UPDATE_TYPE;
+
+	return 0;
+}
+
+static void crystalcove_bus_lock(struct irq_data *data)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(data);
+	struct crystalcove_gpio *cg =
+		container_of(gc, struct crystalcove_gpio, chip);
+
+	mutex_lock(&cg->buslock);
+}
+
+static void crystalcove_bus_sync_unlock(struct irq_data *data)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(data);
+	struct crystalcove_gpio *cg =
+		container_of(gc, struct crystalcove_gpio, chip);
+	int gpio = data->hwirq;
+
+	if (cg->update & UPDATE_TYPE)
+		crystalcove_update_irq_type(gpio, cg->trigger_type);
+	if (cg->update & UPDATE_MASK)
+		crystalcove_update_irq_mask(gpio, cg->set_irq_mask);
+	cg->update = 0;
+
+	mutex_unlock(&cg->buslock);
+}
+
+static void crystalcove_irq_unmask(struct irq_data *data)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(data);
+	struct crystalcove_gpio *cg =
+		container_of(gc, struct crystalcove_gpio, chip);
+
+	cg->set_irq_mask = false;
+	cg->update |= UPDATE_MASK;
+}
+
+static void crystalcove_irq_mask(struct irq_data *data)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(data);
+	struct crystalcove_gpio *cg =
+		container_of(gc, struct crystalcove_gpio, chip);
+
+	cg->set_irq_mask = true;
+	cg->update |= UPDATE_MASK;
+}
+
+static struct irq_chip crystalcove_irqchip = {
+	.name			= "PMIC-GPIO",
+	.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;
+	int pending;
+	int gpio;
+	unsigned int virq;
+
+	pending = intel_soc_pmic_readb(GPIO0IRQ);
+	pending |= intel_soc_pmic_readb(GPIO1IRQ) << 8;
+	intel_soc_pmic_writeb(GPIO0IRQ, pending & 0xff);
+	intel_soc_pmic_writeb(GPIO1IRQ, (pending >> 8) & 0xff);
+
+	local_irq_disable();
+	for (gpio = 0; gpio < cg->chip.ngpio; gpio++) {
+		if (pending & BIT(gpio)) {
+			virq = irq_find_mapping(cg->chip.irqdomain, gpio);
+			if (virq)
+				generic_handle_irq(virq);
+		}
+	}
+	local_irq_enable();
+
+	return IRQ_HANDLED;
+}
+
+static void crystalcove_gpio_dbg_show(struct seq_file *s,
+				      struct gpio_chip *chip)
+{
+	struct crystalcove_gpio *cg =
+		container_of(chip, struct crystalcove_gpio, chip);
+	int gpio, offset;
+	u8 ctlo, ctli, mirqs0, mirqsx, irq;
+
+	for (gpio = 0; gpio < cg->chip.ngpio; gpio++) {
+		ctlo = intel_soc_pmic_readb(GPIO_TO_CTL(gpio, O));
+		ctli = intel_soc_pmic_readb(GPIO_TO_CTL(gpio, I));
+		mirqs0 = intel_soc_pmic_readb(
+			gpio < 8 ? MGPIO0IRQS0 : MGPIO1IRQS0);
+		mirqsx = intel_soc_pmic_readb(
+			gpio < 8 ? MGPIO0IRQSX : MGPIO1IRQSX);
+		irq = intel_soc_pmic_readb(
+			gpio < 8 ? GPIO0IRQ : GPIO1IRQ);
+
+		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;
+
+	cg = devm_kzalloc(&pdev->dev, sizeof(*cg), GFP_KERNEL);
+
+	mutex_init(&cg->buslock);
+	cg->chip.label = KBUILD_MODNAME;
+	cg->chip.direction_input = crystalcove_gpio_direction_input;
+	cg->chip.direction_output = crystalcove_gpio_direction_output;
+	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;
+
+	gpiochip_irqchip_add(&cg->chip, &crystalcove_irqchip, 0,
+			     handle_simple_irq, IRQ_TYPE_NONE);
+
+	retval = gpiochip_add(&cg->chip);
+	if (retval) {
+		dev_warn(&pdev->dev, "add gpio chip error: %d\n", retval);
+		goto out;
+	}
+
+	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_remove_gpio;
+	}
+
+	platform_set_drvdata(pdev, cg);
+
+	return 0;
+
+out_remove_gpio:
+	WARN_ON(gpiochip_remove(&cg->chip));
+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",
+	},
+};
+
+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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