pinctrl: st: Add Interrupt support

This patch add interrupt support to the pincontroller driver.

ST Pincontroller GPIO bank can have one of the two possible types of
interrupt-wirings.

First type is via irqmux, single interrupt is used by multiple gpio
banks. This reduces number of overall interrupts numbers required. All
these banks belong to a single pincontroller.
		  _________
		 |	   |----> [gpio-bank (n)    ]
		 |	   |----> [gpio-bank (n + 1)]
	[irqN]-- | irq-mux |----> [gpio-bank (n + 2)]
		 |	   |----> [gpio-bank (...  )]
		 |_________|----> [gpio-bank (n + 7)]

Second type has a dedicated interrupt per gpio bank.

	[irqN]----> [gpio-bank (n)]

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@st.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

1 files changed, 223 insertions, 2 deletions

diff --git a/drivers/pinctrl/pinctrl-st.c b/drivers/pinctrl/pinctrl-st.c
index 320c273..51e4f3a 100644
--- a/drivers/pinctrl/pinctrl-st.c
+++ b/drivers/pinctrl/pinctrl-st.c
@@ -13,7 +13,12 @@
 #include <linux/slab.h>
 #include <linux/err.h>
 #include <linux/io.h>
+#include <linux/irq.h>
+#include <linux/irqdesc.h>
+#include <linux/irqdomain.h>
+#include <linux/irqchip/chained_irq.h>
 #include <linux/of.h>
+#include <linux/of_irq.h>
 #include <linux/of_gpio.h>
 #include <linux/of_address.h>
 #include <linux/regmap.h>
@@ -271,6 +276,7 @@ struct st_gpio_bank {
 	struct pinctrl_gpio_range	range;
 	void __iomem			*base;
 	struct st_pio_control		pc;
+	struct	irq_domain		*domain;
 };
 
 struct st_pinctrl {
@@ -284,6 +290,7 @@ struct st_pinctrl {
 	int				ngroups;
 	struct regmap			*regmap;
 	const struct st_pctl_data	*data;
+	void __iomem			*irqmux_base;
 };
 
 /* SOC specific data */
@@ -1200,6 +1207,130 @@ static int st_pctl_parse_functions(struct device_node *np,
 	return 0;
 }
 
+static int st_gpio_to_irq(struct gpio_chip *chip, unsigned offset)
+{
+	struct st_gpio_bank *bank = gpio_chip_to_bank(chip);
+	int irq = -ENXIO;
+
+	if (offset < chip->ngpio)
+		irq = irq_find_mapping(bank->domain, offset);
+
+	dev_info(chip->dev, "%s: request IRQ for GPIO %d, return %d\n",
+				chip->label, offset + chip->base, irq);
+	return irq;
+}
+
+static void st_gpio_irq_mask(struct irq_data *d)
+{
+	struct st_gpio_bank *bank = irq_data_get_irq_chip_data(d);
+
+	writel(BIT(d->hwirq), bank->base + REG_PIO_CLR_PMASK);
+}
+
+static void st_gpio_irq_unmask(struct irq_data *d)
+{
+	struct st_gpio_bank *bank = irq_data_get_irq_chip_data(d);
+
+	writel(BIT(d->hwirq), bank->base + REG_PIO_SET_PMASK);
+}
+
+static unsigned int st_gpio_irq_startup(struct irq_data *d)
+{
+	struct st_gpio_bank *bank = irq_data_get_irq_chip_data(d);
+
+	if (gpio_lock_as_irq(&bank->gpio_chip, d->hwirq))
+		dev_err(bank->gpio_chip.dev,
+			"unable to lock HW IRQ %lu for IRQ\n",
+			d->hwirq);
+
+	st_gpio_irq_unmask(d);
+
+	return 0;
+}
+
+static void st_gpio_irq_shutdown(struct irq_data *d)
+{
+	struct st_gpio_bank *bank = irq_data_get_irq_chip_data(d);
+
+	st_gpio_irq_mask(d);
+	gpio_unlock_as_irq(&bank->gpio_chip, d->hwirq);
+}
+
+static int st_gpio_irq_set_type(struct irq_data *d, unsigned type)
+{
+	struct st_gpio_bank *bank = irq_data_get_irq_chip_data(d);
+	unsigned long flags;
+	int comp, pin = d->hwirq;
+	u32 val;
+
+	switch (type) {
+	case IRQ_TYPE_LEVEL_HIGH:
+		comp = 0;
+		break;
+	case IRQ_TYPE_LEVEL_LOW:
+		comp = 1;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	val = readl(bank->base + REG_PIO_PCOMP);
+	val &= ~BIT(pin);
+	val |= (comp << pin);
+	writel(val, bank->base + REG_PIO_PCOMP);
+
+	return 0;
+}
+
+static void __gpio_irq_handler(struct st_gpio_bank *bank)
+{
+	unsigned long port_in, port_mask, port_comp, active_irqs;
+	int n;
+
+	for (;;) {
+		port_in = readl(bank->base + REG_PIO_PIN);
+		port_comp = readl(bank->base + REG_PIO_PCOMP);
+		port_mask = readl(bank->base + REG_PIO_PMASK);
+
+		active_irqs = (port_in ^ port_comp) & port_mask;
+
+		if (active_irqs == 0)
+			break;
+
+		for_each_set_bit(n, &active_irqs, BITS_PER_LONG) {
+			generic_handle_irq(irq_find_mapping(bank->domain, n));
+		}
+	}
+}
+
+static void st_gpio_irq_handler(unsigned irq, struct irq_desc *desc)
+{
+	/* interrupt dedicated per bank */
+	struct irq_chip *chip = irq_get_chip(irq);
+	struct st_gpio_bank *bank = irq_get_handler_data(irq);
+
+	chained_irq_enter(chip, desc);
+	__gpio_irq_handler(bank);
+	chained_irq_exit(chip, desc);
+}
+
+static void st_gpio_irqmux_handler(unsigned irq, struct irq_desc *desc)
+{
+	struct irq_chip *chip = irq_get_chip(irq);
+	struct st_pinctrl *info = irq_get_handler_data(irq);
+	unsigned long status;
+	int n;
+
+	chained_irq_enter(chip, desc);
+
+	status = readl(info->irqmux_base);
+
+	for_each_set_bit(n, &status, ST_GPIO_PINS_PER_BANK)
+		__gpio_irq_handler(&info->banks[n]);
+
+	chained_irq_exit(chip, desc);
+}
+
 static struct gpio_chip st_gpio_template = {
 	.request		= st_gpio_request,
 	.free			= st_gpio_free,
@@ -1210,6 +1341,34 @@ static struct gpio_chip st_gpio_template = {
 	.ngpio			= ST_GPIO_PINS_PER_BANK,
 	.of_gpio_n_cells	= 1,
 	.of_xlate		= st_gpio_xlate,
+	.to_irq			= st_gpio_to_irq,
+};
+
+static struct irq_chip st_gpio_irqchip = {
+	.name		= "GPIO",
+	.irq_mask	= st_gpio_irq_mask,
+	.irq_unmask	= st_gpio_irq_unmask,
+	.irq_set_type	= st_gpio_irq_set_type,
+	.irq_startup	= st_gpio_irq_startup,
+	.irq_shutdown	= st_gpio_irq_shutdown,
+};
+
+static int st_gpio_irq_domain_map(struct irq_domain *h,
+			unsigned int virq, irq_hw_number_t hw)
+{
+	struct st_gpio_bank *bank = h->host_data;
+
+	irq_set_chip(virq, &st_gpio_irqchip);
+	irq_set_handler(virq, handle_level_irq);
+	set_irq_flags(virq, IRQF_VALID);
+	irq_set_chip_data(virq, bank);
+
+	return 0;
+}
+
+static struct irq_domain_ops st_gpio_irq_ops = {
+	.map	= st_gpio_irq_domain_map,
+	.xlate	= irq_domain_xlate_twocell,
 };
 
 static int st_gpiolib_register_bank(struct st_pinctrl *info,
@@ -1219,8 +1378,8 @@ static int st_gpiolib_register_bank(struct st_pinctrl *info,
 	struct pinctrl_gpio_range *range = &bank->range;
 	struct device *dev = info->dev;
 	int bank_num = of_alias_get_id(np, "gpio");
-	struct resource res;
-	int err;
+	struct resource res, irq_res;
+	int gpio_irq = 0, err, i;
 
 	if (of_address_to_resource(np, 0, &res))
 		return -ENODEV;
@@ -1248,6 +1407,51 @@ static int st_gpiolib_register_bank(struct st_pinctrl *info,
 	}
 	dev_info(dev, "%s bank added.\n", range->name);
 
+	/**
+	 * GPIO bank can have one of the two possible types of
+	 * interrupt-wirings.
+	 *
+	 * First type is via irqmux, single interrupt is used by multiple
+	 * gpio banks. This reduces number of overall interrupts numbers
+	 * required. All these banks belong to a single pincontroller.
+	 *		  _________
+	 *		 |	   |----> [gpio-bank (n)    ]
+	 *		 |	   |----> [gpio-bank (n + 1)]
+	 *	[irqN]-- | irq-mux |----> [gpio-bank (n + 2)]
+	 *		 |	   |----> [gpio-bank (...  )]
+	 *		 |_________|----> [gpio-bank (n + 7)]
+	 *
+	 * Second type has a dedicated interrupt per each gpio bank.
+	 *
+	 *	[irqN]----> [gpio-bank (n)]
+	 */
+
+	if (!of_irq_to_resource(np, 0, &irq_res)) {
+		gpio_irq = irq_res.start;
+		irq_set_chained_handler(gpio_irq, st_gpio_irq_handler);
+		irq_set_handler_data(gpio_irq, bank);
+	}
+
+	if (info->irqmux_base > 0 || gpio_irq > 0) {
+		/* Setup IRQ domain */
+		bank->domain  = irq_domain_add_linear(np,
+						ST_GPIO_PINS_PER_BANK,
+						&st_gpio_irq_ops, bank);
+		if (!bank->domain) {
+			dev_err(dev, "Failed to add irq domain for %s\n",
+				np->full_name);
+		} else  {
+			for (i = 0; i < ST_GPIO_PINS_PER_BANK; i++) {
+				if (irq_create_mapping(bank->domain, i) < 0)
+					dev_err(dev,
+						"Failed to map IRQ %i\n", i);
+			}
+		}
+
+	} else {
+		dev_info(dev, "No IRQ support for %s bank\n", np->full_name);
+	}
+
 	return 0;
 }
 
@@ -1276,6 +1480,8 @@ static int st_pctl_probe_dt(struct platform_device *pdev,
 	struct device_node *np = pdev->dev.of_node;
 	struct device_node *child;
 	int grp_index = 0;
+	int irq = 0;
+	struct resource *res;
 
 	st_pctl_dt_child_count(info, np);
 	if (!info->nbanks) {
@@ -1306,6 +1512,21 @@ static int st_pctl_probe_dt(struct platform_device *pdev,
 	}
 	info->data = of_match_node(st_pctl_of_match, np)->data;
 
+	irq = platform_get_irq(pdev, 0);
+
+	if (irq > 0) {
+		res = platform_get_resource_byname(pdev,
+					IORESOURCE_MEM, "irqmux");
+		info->irqmux_base = devm_ioremap_resource(&pdev->dev, res);
+
+		if (IS_ERR(info->irqmux_base))
+			return PTR_ERR(info->irqmux_base);
+
+		irq_set_chained_handler(irq, st_gpio_irqmux_handler);
+		irq_set_handler_data(irq, info);
+
+	}
+
 	pctl_desc->npins = info->nbanks * ST_GPIO_PINS_PER_BANK;
 	pdesc =	devm_kzalloc(&pdev->dev,
 			sizeof(*pdesc) * pctl_desc->npins, GFP_KERNEL);