[PATCH V6 6/8] gpio: max77620: add gpio driver for MAX77620/MAX20024

[Laxman Dewangan <ldewangan@nvidia.com>]

MAXIM Semiconductor's PMIC, MAX77620/MAX20024 has 8 GPIO
pins. It also supports interrupts from these pins.

Add GPIO driver for these pins to control via GPIO APIs.

Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
---
Changes from V1:
- Use the gpiochip_add_data and get the chip data from core APIs.
- Cleanups based on comment received on mfd/rtc.
- Avoid duplication on error message.

Changes form V2:
- Run coccicheck and checkpatch in strict mode for the alignment.
- update based on api changes from core.

Changes from V3: 
- Change all sys initcall to module driver.
- change the max77620_read argument to unisgned int from u8.

Changes from V4: 
- Added DT binding document as devicetree/bindings/gpio/gpio-max77620.txt

Changes from V5:  
- Separate out DT binding doc for gpio.
- Added reviewed by for Linus W

 drivers/gpio/Kconfig         |   9 ++
 drivers/gpio/Makefile        |   1 +
 drivers/gpio/gpio-max77620.c | 292 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 302 insertions(+)
 create mode 100644 drivers/gpio/gpio-max77620.c

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index c88dd24..48c614e 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -797,6 +797,15 @@ config GPIO_LP3943
 	  LP3943 can be used as a GPIO expander which provides up to 16 GPIOs.
 	  Open drain outputs are required for this usage.
 
+config GPIO_MAX77620
+	bool "GPIO support for PMIC MAX77620 and MAX20024"
+	depends on MFD_MAX77620
+	help
+	  GPIO driver for MAX77620 and MAX20024 PMIC from Maxim Semiconductor.
+	  MAX77620 PMIC has 8 pins that can be configured as GPIOs. The
+	  driver also provides interrupt support for each of the gpios.
+	  Say yes here to enable the max77620 to be used as gpio controller.
+
 config GPIO_MSIC
 	bool "Intel MSIC mixed signal gpio support"
 	depends on MFD_INTEL_MSIC
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index ece7d7c..f676a2d 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -57,6 +57,7 @@ obj-$(CONFIG_GPIO_MAX730X)	+= gpio-max730x.o
 obj-$(CONFIG_GPIO_MAX7300)	+= gpio-max7300.o
 obj-$(CONFIG_GPIO_MAX7301)	+= gpio-max7301.o
 obj-$(CONFIG_GPIO_MAX732X)	+= gpio-max732x.o
+obj-$(CONFIG_GPIO_MAX77620)	+= gpio-max77620.o
 obj-$(CONFIG_GPIO_MB86S7X)	+= gpio-mb86s7x.o
 obj-$(CONFIG_GPIO_MC33880)	+= gpio-mc33880.o
 obj-$(CONFIG_GPIO_MC9S08DZ60)	+= gpio-mc9s08dz60.o
diff --git a/drivers/gpio/gpio-max77620.c b/drivers/gpio/gpio-max77620.c
new file mode 100644
index 0000000..4900dd5
--- /dev/null
+++ b/drivers/gpio/gpio-max77620.c
@@ -0,0 +1,292 @@
+/*
+ * MAXIM MAX77620 GPIO driver
+ *
+ * Copyright (c) 2016, NVIDIA CORPORATION.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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/interrupt.h>
+#include <linux/gpio.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/mfd/max77620.h>
+
+#define GPIO_REG_ADDR(offset) (MAX77620_REG_GPIO0 + offset)
+
+struct max77620_gpio {
+	struct gpio_chip	gpio_chip;
+	struct device		*parent;
+	struct device		*dev;
+	int			gpio_irq;
+	int			irq_base;
+	int			gpio_base;
+};
+
+static const struct regmap_irq max77620_gpio_irqs[] = {
+	[MAX77620_IRQ_GPIO0 - MAX77620_IRQ_GPIO0] = {
+		.mask = MAX77620_IRQ_LVL2_GPIO_EDGE0,
+		.reg_offset = 0,
+	},
+	[MAX77620_IRQ_GPIO1 - MAX77620_IRQ_GPIO0] = {
+		.mask = MAX77620_IRQ_LVL2_GPIO_EDGE1,
+		.reg_offset = 0,
+	},
+	[MAX77620_IRQ_GPIO2 - MAX77620_IRQ_GPIO0] = {
+		.mask = MAX77620_IRQ_LVL2_GPIO_EDGE2,
+		.reg_offset = 0,
+	},
+	[MAX77620_IRQ_GPIO3 - MAX77620_IRQ_GPIO0] = {
+		.mask = MAX77620_IRQ_LVL2_GPIO_EDGE3,
+		.reg_offset = 0,
+	},
+	[MAX77620_IRQ_GPIO4 - MAX77620_IRQ_GPIO0] = {
+		.mask = MAX77620_IRQ_LVL2_GPIO_EDGE4,
+		.reg_offset = 0,
+	},
+	[MAX77620_IRQ_GPIO5 - MAX77620_IRQ_GPIO0] = {
+		.mask = MAX77620_IRQ_LVL2_GPIO_EDGE5,
+		.reg_offset = 0,
+	},
+	[MAX77620_IRQ_GPIO6 - MAX77620_IRQ_GPIO0] = {
+		.mask = MAX77620_IRQ_LVL2_GPIO_EDGE6,
+		.reg_offset = 0,
+	},
+	[MAX77620_IRQ_GPIO7 - MAX77620_IRQ_GPIO0] = {
+		.mask = MAX77620_IRQ_LVL2_GPIO_EDGE7,
+		.reg_offset = 0,
+	},
+};
+
+static struct regmap_irq_chip max77620_gpio_irq_chip = {
+	.name = "max77620-gpio",
+	.irqs = max77620_gpio_irqs,
+	.num_irqs = ARRAY_SIZE(max77620_gpio_irqs),
+	.num_regs = 1,
+	.irq_reg_stride = 1,
+	.status_base = MAX77620_REG_IRQ_LVL2_GPIO,
+};
+
+static int max77620_gpio_dir_input(struct gpio_chip *gc, unsigned offset)
+{
+	struct max77620_gpio *mgpio = gpiochip_get_data(gc);
+	int ret;
+
+	ret = max77620_reg_update(mgpio->parent, GPIO_REG_ADDR(offset),
+				  MAX77620_CNFG_GPIO_DIR_MASK,
+				  MAX77620_CNFG_GPIO_DIR_INPUT);
+	if (ret < 0)
+		dev_err(mgpio->dev, "CNFG_GPIOx dir update failed: %d\n", ret);
+
+	return ret;
+}
+
+static int max77620_gpio_get(struct gpio_chip *gc, unsigned offset)
+{
+	struct max77620_gpio *mgpio = gpiochip_get_data(gc);
+	unsigned int val;
+	int ret;
+
+	ret = max77620_reg_read(mgpio->parent, GPIO_REG_ADDR(offset), &val);
+	if (ret < 0) {
+		dev_err(mgpio->dev, "CNFG_GPIOx read failed: %d\n", ret);
+		return ret;
+	}
+
+	return !!(val & MAX77620_CNFG_GPIO_INPUT_VAL_MASK);
+}
+
+static int max77620_gpio_dir_output(struct gpio_chip *gc, unsigned offset,
+				    int value)
+{
+	struct max77620_gpio *mgpio = gpiochip_get_data(gc);
+	u8 val;
+	int ret;
+
+	val = (value) ? MAX77620_CNFG_GPIO_OUTPUT_VAL_HIGH :
+				MAX77620_CNFG_GPIO_OUTPUT_VAL_LOW;
+
+	ret = max77620_reg_update(mgpio->parent, GPIO_REG_ADDR(offset),
+				  MAX77620_CNFG_GPIO_OUTPUT_VAL_MASK, val);
+	if (ret < 0) {
+		dev_err(mgpio->dev, "CNFG_GPIOx val update failed: %d\n", ret);
+		return ret;
+	}
+
+	ret = max77620_reg_update(mgpio->parent, GPIO_REG_ADDR(offset),
+				  MAX77620_CNFG_GPIO_DIR_MASK,
+				  MAX77620_CNFG_GPIO_DIR_OUTPUT);
+	if (ret < 0)
+		dev_err(mgpio->dev, "CNFG_GPIOx dir update failed: %d\n", ret);
+
+	return ret;
+}
+
+static int max77620_gpio_set_debounce(struct gpio_chip *gc,
+				      unsigned offset, unsigned debounce)
+{
+	struct max77620_gpio *mgpio = gpiochip_get_data(gc);
+	u8 val;
+	int ret;
+
+	switch (debounce) {
+	case 0:
+		val = MAX77620_CNFG_GPIO_DBNC_None;
+		break;
+	case 1 ... 8:
+		val = MAX77620_CNFG_GPIO_DBNC_8ms;
+		break;
+	case 9 ... 16:
+		val = MAX77620_CNFG_GPIO_DBNC_16ms;
+		break;
+	case 17 ... 32:
+		val = MAX77620_CNFG_GPIO_DBNC_32ms;
+		break;
+	default:
+		dev_err(mgpio->dev, "Illegal value %u\n", debounce);
+		return -EINVAL;
+	}
+
+	ret = max77620_reg_update(mgpio->parent, GPIO_REG_ADDR(offset),
+				  MAX77620_CNFG_GPIO_DBNC_MASK, val);
+	if (ret < 0)
+		dev_err(mgpio->dev, "CNFG_GPIOx_DBNC update failed: %d\n", ret);
+
+	return ret;
+}
+
+static void max77620_gpio_set(struct gpio_chip *gc, unsigned offset,
+			      int value)
+{
+	struct max77620_gpio *mgpio = gpiochip_get_data(gc);
+	u8 val;
+	int ret;
+
+	val = (value) ? MAX77620_CNFG_GPIO_OUTPUT_VAL_HIGH :
+				MAX77620_CNFG_GPIO_OUTPUT_VAL_LOW;
+
+	ret = max77620_reg_update(mgpio->parent, GPIO_REG_ADDR(offset),
+				  MAX77620_CNFG_GPIO_OUTPUT_VAL_MASK, val);
+	if (ret < 0)
+		dev_err(mgpio->dev, "CNFG_GPIO_OUT update failed: %d\n", ret);
+}
+
+static int max77620_gpio_to_irq(struct gpio_chip *gc, unsigned offset)
+{
+	struct max77620_gpio *mgpio = gpiochip_get_data(gc);
+	struct max77620_chip *chip = dev_get_drvdata(mgpio->dev->parent);
+
+	return regmap_irq_get_virq(chip->gpio_irq_data, offset);
+}
+
+static void max77620_gpio_irq_remove(struct max77620_gpio *mgpio)
+{
+	struct max77620_chip *chip = dev_get_drvdata(mgpio->dev->parent);
+
+	regmap_del_irq_chip(mgpio->gpio_irq, chip->gpio_irq_data);
+	chip->gpio_irq_data = NULL;
+}
+
+static int max77620_gpio_probe(struct platform_device *pdev)
+{
+	struct max77620_gpio *mgpio;
+	struct max77620_chip *chip =  dev_get_drvdata(pdev->dev.parent);
+	int ret;
+	int gpio_irq;
+
+	gpio_irq = platform_get_irq(pdev, 0);
+	if (gpio_irq <= 0) {
+		dev_err(&pdev->dev, "GPIO irq not available %d\n", gpio_irq);
+		return -ENODEV;
+	}
+
+	mgpio = devm_kzalloc(&pdev->dev, sizeof(*mgpio), GFP_KERNEL);
+	if (!mgpio)
+		return -ENOMEM;
+
+	mgpio->parent = pdev->dev.parent;
+	mgpio->dev = &pdev->dev;
+	mgpio->gpio_irq = gpio_irq;
+
+	mgpio->gpio_chip.label = pdev->name;
+	mgpio->gpio_chip.parent = &pdev->dev;
+	mgpio->gpio_chip.direction_input = max77620_gpio_dir_input;
+	mgpio->gpio_chip.get = max77620_gpio_get;
+	mgpio->gpio_chip.direction_output = max77620_gpio_dir_output;
+	mgpio->gpio_chip.set_debounce = max77620_gpio_set_debounce;
+	mgpio->gpio_chip.set = max77620_gpio_set;
+	mgpio->gpio_chip.to_irq = max77620_gpio_to_irq;
+	mgpio->gpio_chip.ngpio = MAX77620_GPIO_NR;
+	mgpio->gpio_chip.can_sleep = 1;
+	mgpio->gpio_chip.base = -1;
+	mgpio->irq_base = -1;
+#ifdef CONFIG_OF_GPIO
+	mgpio->gpio_chip.of_node = pdev->dev.parent->of_node;
+#endif
+
+	platform_set_drvdata(pdev, mgpio);
+
+	ret = gpiochip_add_data(&mgpio->gpio_chip, mgpio);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "gpio_init: Failed to add max77620_gpio\n");
+		return ret;
+	}
+	mgpio->gpio_base = mgpio->gpio_chip.base;
+
+	ret = regmap_add_irq_chip(chip->rmap, mgpio->gpio_irq, IRQF_ONESHOT,
+				  mgpio->irq_base,
+				  &max77620_gpio_irq_chip,
+				  &chip->gpio_irq_data);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "Failed to add gpio irq_chip %d\n", ret);
+		goto fail;
+	}
+
+	return 0;
+
+fail:
+	gpiochip_remove(&mgpio->gpio_chip);
+
+	return ret;
+}
+
+static int max77620_gpio_remove(struct platform_device *pdev)
+{
+	struct max77620_gpio *mgpio = platform_get_drvdata(pdev);
+
+	max77620_gpio_irq_remove(mgpio);
+	gpiochip_remove(&mgpio->gpio_chip);
+
+	return 0;
+}
+
+static const struct platform_device_id max77620_gpio_devtype[] = {
+	{ .name = "max77620-gpio", },
+	{ .name = "max20024-gpio", },
+	{},
+};
+MODULE_DEVICE_TABLE(platform, max77620_gpio_devtype);
+
+static struct platform_driver max77620_gpio_driver = {
+	.driver.name	= "max77620-gpio",
+	.driver.owner	= THIS_MODULE,
+	.probe		= max77620_gpio_probe,
+	.remove		= max77620_gpio_remove,
+	.id_table	= max77620_gpio_devtype,
+};
+
+module_platform_driver(max77620_gpio_driver);
+
+MODULE_DESCRIPTION("GPIO interface for MAX77620 and MAX20024 PMIC");
+MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
+MODULE_AUTHOR("Chaitanya Bandi <bandik@nvidia.com>");
+MODULE_ALIAS("platform:max77620-gpio");
+MODULE_LICENSE("GPL v2");
-- 
2.1.4