[PATCH 11/18] gpio: adp5585: support gpi events

["Nuno Sá via B4 Relay" <devnull+nuno.sa.analog.com@kernel.org>]

From: Nuno Sá <nuno.sa@analog.com>

Add support for adding GPIs to the event FIFO. This is done by adding
irq_chip support. Like this, one can use the input gpio_keys driver as a
"frontend" device and input handler.

As part of this change, we now implement .init_valid_mask() as we can't
blindly consume all available pins as GPIOs (example: some pins can be
used for forming a keymap matrix).

Signed-off-by: Nuno Sá <nuno.sa@analog.com>
---
 drivers/gpio/Kconfig        |   1 +
 drivers/gpio/gpio-adp5585.c | 178 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 179 insertions(+)

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 98b4d1633b258b93d05ba66d53f647e7ec6ac364..e8dc5cb9df0f62b111810d90ae67ce68b382d434 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -1238,6 +1238,7 @@ config GPIO_ADP5520
 config GPIO_ADP5585
 	tristate "GPIO Support for ADP5585"
 	depends on MFD_ADP5585
+	select GPIOLIB_IRQCHIP
 	help
 	  This option enables support for the GPIO function found in the Analog
 	  Devices ADP5585.
diff --git a/drivers/gpio/gpio-adp5585.c b/drivers/gpio/gpio-adp5585.c
index fded9ff35a59fc1a0ce173c58dbd7b6af176958f..cfd0aab1f7414f76287714eda44184c615491194 100644
--- a/drivers/gpio/gpio-adp5585.c
+++ b/drivers/gpio/gpio-adp5585.c
@@ -11,6 +11,7 @@
 #include <linux/gpio/driver.h>
 #include <linux/mfd/adp5585.h>
 #include <linux/module.h>
+#include <linux/mutex.h>
 #include <linux/platform_device.h>
 #include <linux/regmap.h>
 #include <linux/types.h>
@@ -27,6 +28,11 @@ struct adp5585_gpio_dev {
 	const struct adp5585_gpio_chip *info;
 	struct regmap *regmap;
 	const struct adp5585_regs *regs;
+	unsigned long irq_mask;
+	unsigned long irq_en;
+	unsigned long irq_active_high;
+	/* used for irqchip bus locking */
+	struct mutex bus_lock;
 };
 
 static int adp5585_gpio_bank(unsigned int off)
@@ -208,12 +214,155 @@ static int adp5585_gpio_set_config(struct gpio_chip *chip, unsigned int off,
 	};
 }
 
+static int adp5585_gpio_init_valid_mask(struct gpio_chip *chip,
+					unsigned long *valid_mask,
+					unsigned int ngpios)
+{
+	struct device *dev = chip->parent;
+	struct adp5585_dev *adp5585 = dev_get_drvdata(dev->parent);
+
+	bitmap_complement(valid_mask, adp5585->keypad, ngpios);
+	/*
+	 * the keypad won't have (nor can't) have any special pin enabled which
+	 * means bitmap_complement() will set them to 1. Make sure we clear them.
+	 */
+	if (adp5585->has_pwm)
+		__clear_bit(ADP5585_ROW3, valid_mask);
+	if (adp5585->nkeys_reset1)
+		__clear_bit(ADP5585_ROW4, valid_mask);
+	if (adp5585->nkeys_reset2)
+		__clear_bit(adp5585->info->max_rows + ADP5585_COL4, valid_mask);
+	if (!adp5585->info->has_row5)
+		__clear_bit(ADP5585_ROW5, valid_mask);
+
+	return 0;
+}
+
+static void adp5585_gpio_key_event(struct device *dev, unsigned int off,
+				   bool key_press)
+{
+	struct adp5585_gpio_dev *adp5585_gpio = dev_get_drvdata(dev);
+	bool active_high = test_bit(off, &adp5585_gpio->irq_active_high);
+	unsigned int irq, irq_type;
+	struct irq_data *irqd;
+
+	irq = irq_find_mapping(adp5585_gpio->gpio_chip.irq.domain, off);
+	if (!irq)
+		return;
+
+	irqd = irq_get_irq_data(irq);
+	if (!irqd) {
+		dev_err(dev, "Could not get irq(%u) data\n", irq);
+		return;
+	}
+
+	dev_dbg_ratelimited(dev, "gpio-keys event(%u) press=%u, a_high=%u\n",
+			    off, key_press, active_high);
+
+	if (!active_high)
+		key_press = !key_press;
+
+	irq_type = irqd_get_trigger_type(irqd);
+
+	if ((irq_type & IRQ_TYPE_EDGE_RISING && key_press) ||
+	    (irq_type & IRQ_TYPE_EDGE_FALLING && !key_press))
+		handle_nested_irq(irq);
+}
+
+static void adp5585_irq_bus_lock(struct irq_data *d)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+	struct adp5585_gpio_dev *adp5585_gpio = gpiochip_get_data(gc);
+
+	mutex_lock(&adp5585_gpio->bus_lock);
+}
+
+static void adp5585_irq_bus_sync_unlock(struct irq_data *d)
+{
+	struct gpio_chip *chip = irq_data_get_irq_chip_data(d);
+	struct adp5585_gpio_dev *adp5585_gpio = gpiochip_get_data(chip);
+	const struct adp5585_regs *regs = adp5585_gpio->regs;
+	irq_hw_number_t hwirq = irqd_to_hwirq(d);
+	bool active_high = test_bit(hwirq, &adp5585_gpio->irq_active_high);
+	bool enabled = test_bit(hwirq, &adp5585_gpio->irq_en);
+	bool masked = test_bit(hwirq, &adp5585_gpio->irq_mask);
+	unsigned int bank = adp5585_gpio->info->bank(hwirq);
+	unsigned int bit = adp5585_gpio->info->bit(hwirq);
+
+	if (masked && !enabled)
+		goto out_unlock;
+	if (!masked && enabled)
+		goto out_unlock;
+
+	regmap_update_bits(adp5585_gpio->regmap, regs->gpi_int_lvl_a + bank, bit,
+			   active_high ? bit : 0);
+	regmap_update_bits(adp5585_gpio->regmap, regs->gpi_ev_a + bank, bit,
+			   masked ? 0 : bit);
+	assign_bit(hwirq, &adp5585_gpio->irq_en, !masked);
+
+out_unlock:
+	mutex_unlock(&adp5585_gpio->bus_lock);
+}
+
+static void adp5585_irq_mask(struct irq_data *d)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+	struct adp5585_gpio_dev *adp5585_gpio = gpiochip_get_data(gc);
+	irq_hw_number_t hwirq = irqd_to_hwirq(d);
+
+	__set_bit(hwirq, &adp5585_gpio->irq_mask);
+	gpiochip_disable_irq(gc, hwirq);
+}
+
+static void adp5585_irq_unmask(struct irq_data *d)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+	struct adp5585_gpio_dev *adp5585_gpio = gpiochip_get_data(gc);
+	irq_hw_number_t hwirq = irqd_to_hwirq(d);
+
+	gpiochip_enable_irq(gc, hwirq);
+	__clear_bit(hwirq, &adp5585_gpio->irq_mask);
+}
+
+static int adp5585_irq_set_type(struct irq_data *d, unsigned int type)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+	struct adp5585_gpio_dev *adp5585_gpio = gpiochip_get_data(gc);
+	irq_hw_number_t hwirq = irqd_to_hwirq(d);
+
+	if (!(type & IRQ_TYPE_EDGE_BOTH))
+		return -EINVAL;
+
+	assign_bit(hwirq, &adp5585_gpio->irq_active_high,
+		   type == IRQ_TYPE_EDGE_RISING);
+
+	irq_set_handler_locked(d, handle_edge_irq);
+	return 0;
+}
+
+static const struct irq_chip adp5585_irq_chip = {
+	.name = "adp5585",
+	.irq_mask = adp5585_irq_mask,
+	.irq_unmask = adp5585_irq_unmask,
+	.irq_bus_lock = adp5585_irq_bus_lock,
+	.irq_bus_sync_unlock = adp5585_irq_bus_sync_unlock,
+	.irq_set_type = adp5585_irq_set_type,
+	.flags = IRQCHIP_SKIP_SET_WAKE | IRQCHIP_IMMUTABLE,
+	GPIOCHIP_IRQ_RESOURCE_HELPERS,
+};
+
+static void adp5585_gpio_ev_handle_clean(void *adp5585)
+{
+	adp5585_gpio_ev_handle_set(adp5585, NULL, NULL);
+}
+
 static int adp5585_gpio_probe(struct platform_device *pdev)
 {
 	struct adp5585_dev *adp5585 = dev_get_drvdata(pdev->dev.parent);
 	const struct platform_device_id *id = platform_get_device_id(pdev);
 	struct adp5585_gpio_dev *adp5585_gpio;
 	struct device *dev = &pdev->dev;
+	struct gpio_irq_chip *girq;
 	struct gpio_chip *gc;
 	int ret;
 
@@ -238,6 +387,7 @@ static int adp5585_gpio_probe(struct platform_device *pdev)
 	gc->get = adp5585_gpio_get_value;
 	gc->set = adp5585_gpio_set_value;
 	gc->set_config = adp5585_gpio_set_config;
+	gc->init_valid_mask = adp5585_gpio_init_valid_mask;
 	gc->can_sleep = true;
 
 	gc->base = -1;
@@ -245,6 +395,34 @@ static int adp5585_gpio_probe(struct platform_device *pdev)
 	gc->label = pdev->name;
 	gc->owner = THIS_MODULE;
 
+	if (device_property_present(dev->parent, "interrupt-controller")) {
+		if (!adp5585->irq)
+			return dev_err_probe(dev, -EINVAL,
+					     "Unable to serve as interrupt controller without IRQ\n");
+
+		girq = &adp5585_gpio->gpio_chip.irq;
+		gpio_irq_chip_set_chip(girq, &adp5585_irq_chip);
+		girq->handler = handle_bad_irq;
+		girq->threaded = true;
+
+		platform_set_drvdata(pdev, adp5585_gpio);
+		adp5585_gpio_ev_handle_set(adp5585, adp5585_gpio_key_event,
+					   dev);
+
+		ret = devm_add_action_or_reset(dev,
+					       adp5585_gpio_ev_handle_clean,
+					       adp5585);
+		if (ret)
+			return ret;
+	}
+
+	/* everything masked by default */
+	adp5585_gpio->irq_mask = ~0UL;
+
+	ret = devm_mutex_init(dev, &adp5585_gpio->bus_lock);
+	if (ret)
+		return ret;
+
 	ret = devm_gpiochip_add_data(dev, &adp5585_gpio->gpio_chip,
 				     adp5585_gpio);
 	if (ret)

-- 
2.48.1