[PATCH v2 4/7] gpio: max7360: Add MAX7360 gpio support

[Mathieu Dubois-Briand]

Add driver for Maxim Integrated MAX7360 GPIO/GPO controller.

Two sets of GPIOs are provided by the device:
- Up to 8 GPIOs, shared with the PWM and rotary encoder functionalities.
  These GPIOs also provide interrupts on input changes.
- Up to 6 GPOs, on unused keypad columns pins.

Co-developed-by: Kamel Bouhara <kamel.bouhara@xxxxxxxxxxx>
Signed-off-by: Kamel Bouhara <kamel.bouhara@xxxxxxxxxxx>
Signed-off-by: Mathieu Dubois-Briand <mathieu.dubois-briand@xxxxxxxxxxx>
---
 drivers/gpio/Kconfig        |  11 ++
 drivers/gpio/Makefile       |   1 +
 drivers/gpio/gpio-max7360.c | 455 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 467 insertions(+)

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 93ee3aa092f8..efe07e21c442 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -1444,6 +1444,17 @@ config GPIO_MADERA
 	help
 	  Support for GPIOs on Cirrus Logic Madera class codecs.
 
+config GPIO_MAX7360
+	tristate "MAX7360 GPIO support"
+	depends on MFD_MAX7360
+	depends on OF_GPIO
+	help
+	  Allows to use MAX7360 I/O Expander PWM lines as GPIO and keypad COL
+	  lines as GPO.
+
+	  This driver can also be built as a module. If so, the module will be
+	  called gpio-max7360.
+
 config GPIO_MAX77620
 	tristate "GPIO support for PMIC MAX77620 and MAX20024"
 	depends on MFD_MAX77620
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index af3ba4d81b58..581341b3e3e4 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -100,6 +100,7 @@ obj-$(CONFIG_GPIO_MAX7300)		+= gpio-max7300.o
 obj-$(CONFIG_GPIO_MAX7301)		+= gpio-max7301.o
 obj-$(CONFIG_GPIO_MAX730X)		+= gpio-max730x.o
 obj-$(CONFIG_GPIO_MAX732X)		+= gpio-max732x.o
+obj-$(CONFIG_GPIO_MAX7360)		+= gpio-max7360.o
 obj-$(CONFIG_GPIO_MAX77620)		+= gpio-max77620.o
 obj-$(CONFIG_GPIO_MAX77650)		+= gpio-max77650.o
 obj-$(CONFIG_GPIO_MB86S7X)		+= gpio-mb86s7x.o
diff --git a/drivers/gpio/gpio-max7360.c b/drivers/gpio/gpio-max7360.c
new file mode 100644
index 000000000000..42f7f3e66d3a
--- /dev/null
+++ b/drivers/gpio/gpio-max7360.c
@@ -0,0 +1,455 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright 2024 Bootlin
+ *
+ * Author: Kamel BOUHARA <kamel.bouhara@xxxxxxxxxxx>
+ * Author: Mathieu Dubois-Briand <mathieu.dubois-briand@xxxxxxxxxxx>
+ */
+
+#include <linux/gpio/consumer.h>
+#include <linux/gpio/driver.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/mfd/max7360.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+
+#define MAX7360_GPIO_PORT	1
+#define MAX7360_GPIO_COL	2
+
+struct max7360_gpio {
+	struct gpio_chip chip;
+	struct device *dev;
+	struct regmap *regmap;
+	unsigned long gpio_function;
+
+	/*
+	 * Interrupts handling data: only used when gpio_function is
+	 * MAX7360_GPIO_PORT.
+	 */
+	u8 masked_interrupts;
+	u8 in_values;
+	unsigned int irq_types[MAX7360_MAX_GPIO];
+};
+
+static void max7360_gpio_set_value(struct gpio_chip *gc,
+				   unsigned int pin, int state)
+{
+	struct max7360_gpio *max7360_gpio = gpiochip_get_data(gc);
+	int ret;
+
+	if (max7360_gpio->gpio_function == MAX7360_GPIO_COL) {
+		int off = MAX7360_MAX_GPIO - (gc->ngpio - pin);
+
+		ret = regmap_write_bits(max7360_gpio->regmap, MAX7360_REG_PORTS,
+					BIT(off), state ? BIT(off) : 0);
+	} else {
+		ret = regmap_write(max7360_gpio->regmap,
+				   MAX7360_REG_PWMBASE + pin, state ? 0xFF : 0);
+	}
+
+	if (ret)
+		dev_err(max7360_gpio->dev,
+			"failed to set value %d on gpio-%d", state, pin);
+}
+
+static int max7360_gpio_get_value(struct gpio_chip *gc, unsigned int pin)
+{
+	struct max7360_gpio *max7360_gpio = gpiochip_get_data(gc);
+	unsigned int val;
+	int off;
+	int ret;
+
+	if (max7360_gpio->gpio_function == MAX7360_GPIO_COL) {
+		off = MAX7360_MAX_GPIO - (gc->ngpio - pin);
+
+		ret = regmap_read(max7360_gpio->regmap, MAX7360_REG_PORTS, &val);
+	} else {
+		off = pin;
+		ret = regmap_read(max7360_gpio->regmap, MAX7360_REG_GPIOIN, &val);
+	}
+
+	if (ret) {
+		dev_err(max7360_gpio->dev, "failed to read gpio-%d", pin);
+		return ret;
+	}
+
+	return !!(val & BIT(off));
+}
+
+static int max7360_gpio_get_direction(struct gpio_chip *gc, unsigned int pin)
+{
+	struct max7360_gpio *max7360_gpio = gpiochip_get_data(gc);
+	unsigned int val;
+	int ret;
+
+	if (max7360_gpio->gpio_function == MAX7360_GPIO_COL)
+		return GPIO_LINE_DIRECTION_OUT;
+
+	ret = regmap_read(max7360_gpio->regmap, MAX7360_REG_GPIOCTRL, &val);
+	if (ret) {
+		dev_err(max7360_gpio->dev, "failed to read gpio-%d direction",
+			pin);
+		return ret;
+	}
+
+	if (val & BIT(pin))
+		return GPIO_LINE_DIRECTION_OUT;
+
+	return GPIO_LINE_DIRECTION_IN;
+}
+
+static int max7360_gpio_direction_input(struct gpio_chip *gc, unsigned int pin)
+{
+	struct max7360_gpio *max7360_gpio = gpiochip_get_data(gc);
+	int ret;
+
+	if (max7360_gpio->gpio_function == MAX7360_GPIO_COL)
+		return -EIO;
+
+	ret = regmap_write_bits(max7360_gpio->regmap, MAX7360_REG_GPIOCTRL,
+				BIT(pin), 0);
+	if (ret) {
+		dev_err(max7360_gpio->dev, "failed to set gpio-%d direction",
+			pin);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int max7360_gpio_direction_output(struct gpio_chip *gc, unsigned int pin,
+					 int state)
+{
+	struct max7360_gpio *max7360_gpio = gpiochip_get_data(gc);
+	int ret;
+
+	if (max7360_gpio->gpio_function == MAX7360_GPIO_PORT) {
+		ret = regmap_write_bits(max7360_gpio->regmap,
+					MAX7360_REG_GPIOCTRL, BIT(pin),
+					BIT(pin));
+		if (ret) {
+			dev_err(max7360_gpio->dev,
+				"failed to set gpio-%d direction", pin);
+			return ret;
+		}
+	}
+
+	max7360_gpio_set_value(gc, pin, state);
+
+	return 0;
+}
+
+static int max7360_gpio_request(struct gpio_chip *gc, unsigned int pin)
+{
+	struct max7360_gpio *max7360_gpio = gpiochip_get_data(gc);
+
+	/*
+	 * GPOs on COL pins (keypad columns) can always be requested: this
+	 * driver has full access to them, up to the number set in chip.ngpio.
+	 * GPIOs on PORT pins are shared with the PWM and rotary encoder
+	 * drivers: they have to be requested from the MFD driver.
+	 */
+	if (max7360_gpio->gpio_function == MAX7360_GPIO_COL)
+		return 0;
+
+	return max7360_port_pin_request(max7360_gpio->dev->parent, pin, true);
+}
+
+static void max7360_gpio_free(struct gpio_chip *gc, unsigned int pin)
+{
+	struct max7360_gpio *max7360_gpio = gpiochip_get_data(gc);
+
+	if (max7360_gpio->gpio_function == MAX7360_GPIO_COL)
+		return;
+
+	max7360_port_pin_request(max7360_gpio->dev->parent, pin, false);
+}
+
+static struct gpio_chip max7360_gpio_chip = {
+	.label                  = "max7360",
+	.request		= max7360_gpio_request,
+	.free			= max7360_gpio_free,
+	.get_direction		= max7360_gpio_get_direction,
+	.direction_input	= max7360_gpio_direction_input,
+	.direction_output	= max7360_gpio_direction_output,
+	.get                    = max7360_gpio_get_value,
+	.set                    = max7360_gpio_set_value,
+	.base                   = -1,
+	.can_sleep              = true,
+};
+
+static irqreturn_t max7360_gpio_irq(int irq, void *data)
+{
+	struct max7360_gpio *max7360_gpio = data;
+	unsigned long pending;
+	unsigned int gpio_irq;
+	unsigned int type;
+	unsigned int count = 0;
+	int val;
+	int irqn;
+	int ret;
+
+	ret = regmap_read(max7360_gpio->regmap, MAX7360_REG_GPIOIN, &val);
+	if (ret) {
+		dev_err(max7360_gpio->dev, "Failed to read gpio values: %d\n",
+			ret);
+		return IRQ_NONE;
+	}
+
+	/* MAX7360 generates interrupts but does not report which pins changed:
+	 * compare the pin value with the value they had in previous interrupt
+	 * and report interrupt if the change match the set IRQ type.
+	 */
+	pending = val ^ max7360_gpio->in_values;
+	for_each_set_bit(irqn, &pending, max7360_gpio->chip.ngpio) {
+		type = max7360_gpio->irq_types[irqn];
+		if (max7360_gpio->masked_interrupts & BIT(irqn))
+			continue;
+		if ((val & BIT(irqn)) && type == IRQ_TYPE_EDGE_FALLING)
+			continue;
+		if (!(val & BIT(irqn)) && type == IRQ_TYPE_EDGE_RISING)
+			continue;
+		gpio_irq = irq_find_mapping(max7360_gpio->chip.irq.domain, irqn);
+		handle_nested_irq(gpio_irq);
+		count++;
+	}
+
+	max7360_gpio->in_values = val;
+
+	if (count == 0)
+		return IRQ_NONE;
+
+	return IRQ_HANDLED;
+}
+
+static void max7360_gpio_irq_unmask(struct irq_data *data)
+{
+	struct max7360_gpio *max7360_gpio;
+	unsigned int pin = irqd_to_hwirq(data);
+	unsigned int val;
+	int ret;
+
+	max7360_gpio = gpiochip_get_data(irq_data_get_irq_chip_data(data));
+
+	/* Read current pin value, so we know if the pin changed in the next
+	 * interrupt.
+	 * No lock should be needed regarding the interrupt handler: as long as
+	 * the corresponding bit has not been cleared in masked_interrupts, this
+	 * gpio is ignored.
+	 */
+	ret = regmap_read(max7360_gpio->regmap, MAX7360_REG_GPIOIN, &val);
+	if (ret)
+		dev_err(max7360_gpio->dev, "Failed to read gpio values: %d\n",
+			ret);
+
+	max7360_gpio->in_values &= ~BIT(pin);
+	max7360_gpio->in_values |= val & BIT(pin);
+
+	ret = regmap_write_bits(max7360_gpio->regmap, MAX7360_REG_PWMCFG + pin,
+				MAX7360_PORT_CFG_INTERRUPT_MASK, 0);
+
+	if (ret)
+		dev_err(max7360_gpio->dev, "failed to unmask gpio-%d", pin);
+
+	max7360_gpio->masked_interrupts &= ~BIT(pin);
+}
+
+static void max7360_gpio_irq_mask(struct irq_data *data)
+{
+	struct max7360_gpio *max7360_gpio;
+	unsigned int pin = irqd_to_hwirq(data);
+	int ret;
+
+	max7360_gpio = gpiochip_get_data(irq_data_get_irq_chip_data(data));
+
+	max7360_gpio->masked_interrupts |= BIT(pin);
+
+	ret = regmap_write_bits(max7360_gpio->regmap, MAX7360_REG_PWMCFG + pin,
+				MAX7360_PORT_CFG_INTERRUPT_MASK,
+				MAX7360_PORT_CFG_INTERRUPT_MASK);
+
+	if (ret)
+		dev_err(max7360_gpio->dev, "failed to mask gpio-%d", pin);
+}
+
+static void max7360_gpio_irq_enable(struct irq_data *data)
+{
+	max7360_gpio_irq_unmask(data);
+}
+
+static void max7360_gpio_irq_disable(struct irq_data *data)
+{
+	max7360_gpio_irq_mask(data);
+}
+
+static int max7360_gpio_irq_set_type(struct irq_data *data,
+				     unsigned int flow_type)
+{
+	struct max7360_gpio *max7360_gpio;
+	unsigned int pin;
+	unsigned int val;
+	int ret;
+
+	pin = irqd_to_hwirq(data);
+	max7360_gpio = gpiochip_get_data(irq_data_get_irq_chip_data(data));
+
+	switch (flow_type) {
+	case IRQ_TYPE_EDGE_RISING:
+		val = 0;
+		break;
+	case IRQ_TYPE_EDGE_FALLING:
+	case IRQ_TYPE_EDGE_BOTH:
+		val = MAX7360_PORT_CFG_INTERRUPT_EDGES;
+		break;
+	default:
+		return -EINVAL;
+	}
+	ret = regmap_write_bits(max7360_gpio->regmap, MAX7360_REG_PWMCFG + pin,
+				MAX7360_PORT_CFG_INTERRUPT_EDGES, val);
+
+	if (ret)
+		dev_err(max7360_gpio->dev, "failed to unmask gpio-%d", pin);
+
+	max7360_gpio->irq_types[pin] = flow_type;
+
+	return 0;
+}
+
+static const struct irq_chip max7360_gpio_irqchip = {
+	.name = "max7360",
+	.irq_enable = max7360_gpio_irq_enable,
+	.irq_disable = max7360_gpio_irq_disable,
+	.irq_mask = max7360_gpio_irq_mask,
+	.irq_unmask = max7360_gpio_irq_unmask,
+	.irq_set_type = max7360_gpio_irq_set_type,
+	.flags = IRQCHIP_IMMUTABLE,
+	GPIOCHIP_IRQ_RESOURCE_HELPERS,
+};
+
+static int max7360_gpio_probe(struct platform_device *pdev)
+{
+	struct max7360_gpio *max7360_gpio;
+	struct platform_device *parent;
+	unsigned int ngpios;
+	unsigned int outconf;
+	struct gpio_irq_chip *girq;
+	unsigned long flags;
+	int irq;
+	int ret;
+
+	if (!pdev->dev.parent) {
+		dev_err(&pdev->dev, "no parent device\n");
+		return -ENODEV;
+	}
+	parent = to_platform_device(pdev->dev.parent);
+
+	max7360_gpio = devm_kzalloc(&pdev->dev, sizeof(struct max7360_gpio),
+				    GFP_KERNEL);
+	if (!max7360_gpio)
+		return -ENOMEM;
+
+	if (of_property_read_u32(pdev->dev.of_node, "ngpios", &ngpios)) {
+		dev_err(&pdev->dev, "Missing ngpios OF property\n");
+		return -ENODEV;
+	}
+
+	max7360_gpio->regmap = dev_get_regmap(pdev->dev.parent, NULL);
+	if (!max7360_gpio->regmap) {
+		dev_err(&pdev->dev, "could not get parent regmap\n");
+		return -ENODEV;
+	}
+
+	max7360_gpio->dev = &pdev->dev;
+	max7360_gpio->chip = max7360_gpio_chip;
+	max7360_gpio->chip.ngpio = ngpios;
+	max7360_gpio->chip.parent = &pdev->dev;
+	max7360_gpio->chip.base = -1;
+	max7360_gpio->gpio_function = (uintptr_t)device_get_match_data(&pdev->dev);
+
+	dev_dbg(&pdev->dev, "gpio count: %d\n", max7360_gpio->chip.ngpio);
+
+	if (max7360_gpio->gpio_function == MAX7360_GPIO_PORT) {
+		/* Port GPIOs: set output mode configuration (constant-current
+		 * or not).
+		 * This property is optional.
+		 */
+		outconf = 0;
+		ret = of_property_read_u32(pdev->dev.of_node,
+					   "maxim,constant-current-disable",
+					   &outconf);
+		if (ret && (ret != -EINVAL)) {
+			dev_err(&pdev->dev,
+				"Failed to read maxim,constant-current-disable OF property\n");
+			return -ENODEV;
+		}
+
+	    regmap_write(max7360_gpio->regmap, MAX7360_REG_GPIOOUTM, outconf);
+	}
+
+	if (max7360_gpio->gpio_function == MAX7360_GPIO_PORT &&
+	    of_property_read_bool(pdev->dev.of_node, "interrupt-controller")) {
+		/* Port GPIOs: declare IRQ chip, if configuration was provided.
+		 */
+		irq = platform_get_irq_byname(parent, "inti");
+		if (irq < 0)
+			return dev_err_probe(&pdev->dev, irq,
+					     "Failed to get IRQ");
+
+		flags = IRQF_TRIGGER_LOW | IRQF_ONESHOT | IRQF_SHARED;
+		ret = devm_request_threaded_irq(&pdev->dev, irq, NULL,
+						max7360_gpio_irq, flags,
+						"max7360-gpio", max7360_gpio);
+		if (ret)
+			return dev_err_probe(&pdev->dev, ret,
+					     "Failed to register interrupt: %d\n",
+					     ret);
+
+		girq = &max7360_gpio->chip.irq;
+		gpio_irq_chip_set_chip(girq, &max7360_gpio_irqchip);
+		girq->parent_handler = NULL;
+		girq->num_parents = 0;
+		girq->parents = NULL;
+		girq->threaded = true;
+		girq->default_type = IRQ_TYPE_NONE;
+		girq->handler = handle_simple_irq;
+	}
+
+	ret = devm_gpiochip_add_data(&pdev->dev, &max7360_gpio->chip, max7360_gpio);
+	if (ret) {
+		dev_err(&pdev->dev, "unable to add gpiochip: %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static const struct of_device_id max7360_gpio_of_match[] = {
+	{
+		.compatible = "maxim,max7360-gpo",
+		.data = (void *)MAX7360_GPIO_COL
+	}, {
+		.compatible = "maxim,max7360-gpio",
+		.data = (void *)MAX7360_GPIO_PORT
+	}, {
+	}
+};
+MODULE_DEVICE_TABLE(of, max7360_gpio_of_match);
+
+static struct platform_driver max7360_gpio_driver = {
+	.driver = {
+		.name	= MAX7360_DRVNAME_GPIO,
+		.of_match_table = of_match_ptr(max7360_gpio_of_match),
+	},
+	.probe		= max7360_gpio_probe,
+};
+module_platform_driver(max7360_gpio_driver);
+
+MODULE_DESCRIPTION("MAX7360 GPIO driver");
+MODULE_AUTHOR("Kamel BOUHARA <kamel.bouhara@xxxxxxxxxxx>");
+MODULE_AUTHOR("Mathieu Dubois-Briand <mathieu.dubois-briand@xxxxxxxxxxx>");
+MODULE_ALIAS("platform:" MAX7360_DRVNAME_GPIO);
+MODULE_LICENSE("GPL");

-- 
2.39.5