mfd: tps65217: Add support for IRQs

Add support for handling IRQs: power button, AC and USB power state
changes. Mask and interrupt bits are shared within one register, which
prevents us to use regmap_irq implementation. New irq_domain is created in
order to add interrupt handling for each tps65217's subsystem. IRQ
resources have been added for charger subsystem to be able to notify about
AC and USB state changes.
Signed-off-by: Marcin Niestroj <m.niestroj@grinn-global.com>
Reviewed-by: Grygorii Strashko <grygorii.strashko@ti.com>
Tested-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

drivers/mfd/Kconfig

@@ -1232,6 +1232,7 @@ config MFD_TPS65217
 	depends on I2C
 	select MFD_CORE
 	select REGMAP_I2C
+	select IRQ_DOMAIN
 	help
 	  If you say yes here you get support for the TPS65217 series of
 	  Power Management / White LED chips.

drivers/mfd/tps65217.c

@@ -15,22 +15,99 @@
  * GNU General Public License for more details.
  */
 
-#include <linux/kernel.h>
 #include <linux/device.h>
-#include <linux/module.h>
-#include <linux/platform_device.h>
+#include <linux/err.h>
 #include <linux/init.h>
+#include <linux/interrupt.h>
 #include <linux/i2c.h>
-#include <linux/slab.h>
-#include <linux/regmap.h>
-#include <linux/err.h>
+#include <linux/irq.h>
+#include <linux/irqdomain.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
 
 #include <linux/mfd/core.h>
 #include <linux/mfd/tps65217.h>
 
-static const struct mfd_cell tps65217s[] = {
+static struct resource charger_resources[] = {
+	DEFINE_RES_IRQ_NAMED(TPS65217_IRQ_AC, "AC"),
+	DEFINE_RES_IRQ_NAMED(TPS65217_IRQ_USB, "USB"),
+};
+
+struct tps65217_irq {
+	int mask;
+	int interrupt;
+};
+
+static const struct tps65217_irq tps65217_irqs[] = {
+	[TPS65217_IRQ_PB] = {
+		.mask = TPS65217_INT_PBM,
+		.interrupt = TPS65217_INT_PBI,
+	},
+	[TPS65217_IRQ_AC] = {
+		.mask = TPS65217_INT_ACM,
+		.interrupt = TPS65217_INT_ACI,
+	},
+	[TPS65217_IRQ_USB] = {
+		.mask = TPS65217_INT_USBM,
+		.interrupt = TPS65217_INT_USBI,
+	},
+};
+
+static void tps65217_irq_lock(struct irq_data *data)
+{
+	struct tps65217 *tps = irq_data_get_irq_chip_data(data);
+
+	mutex_lock(&tps->irq_lock);
+}
+
+static void tps65217_irq_sync_unlock(struct irq_data *data)
+{
+	struct tps65217 *tps = irq_data_get_irq_chip_data(data);
+	int ret;
+
+	ret = tps65217_reg_write(tps, TPS65217_REG_INT, tps->irq_mask,
+				TPS65217_PROTECT_NONE);
+	if (ret != 0)
+		dev_err(tps->dev, "Failed to sync IRQ masks\n");
+
+	mutex_unlock(&tps->irq_lock);
+}
+
+static const inline struct tps65217_irq *
+irq_to_tps65217_irq(struct tps65217 *tps, struct irq_data *data)
+{
+	return &tps65217_irqs[data->hwirq];
+}
+
+static void tps65217_irq_enable(struct irq_data *data)
+{
+	struct tps65217 *tps = irq_data_get_irq_chip_data(data);
+	const struct tps65217_irq *irq_data = irq_to_tps65217_irq(tps, data);
+
+	tps->irq_mask &= ~irq_data->mask;
+}
+
+static void tps65217_irq_disable(struct irq_data *data)
+{
+	struct tps65217 *tps = irq_data_get_irq_chip_data(data);
+	const struct tps65217_irq *irq_data = irq_to_tps65217_irq(tps, data);
+
+	tps->irq_mask |= irq_data->mask;
+}
+
+static struct irq_chip tps65217_irq_chip = {
+	.irq_bus_lock		= tps65217_irq_lock,
+	.irq_bus_sync_unlock	= tps65217_irq_sync_unlock,
+	.irq_enable		= tps65217_irq_enable,
+	.irq_disable		= tps65217_irq_disable,
+};
+
+static struct mfd_cell tps65217s[] = {
 	{
 		.name = "tps65217-pmic",
 		.of_compatible = "ti,tps65217-pmic",
@@ -41,10 +118,90 @@ static const struct mfd_cell tps65217s[] = {
 	},
 	{
 		.name = "tps65217-charger",
+		.num_resources = ARRAY_SIZE(charger_resources),
+		.resources = charger_resources,
 		.of_compatible = "ti,tps65217-charger",
 	},
 };
 
+static irqreturn_t tps65217_irq_thread(int irq, void *data)
+{
+	struct tps65217 *tps = data;
+	unsigned int status;
+	bool handled = false;
+	int i;
+	int ret;
+
+	ret = tps65217_reg_read(tps, TPS65217_REG_INT, &status);
+	if (ret < 0) {
+		dev_err(tps->dev, "Failed to read IRQ status: %d\n",
+			ret);
+		return IRQ_NONE;
+	}
+
+	for (i = 0; i < ARRAY_SIZE(tps65217_irqs); i++) {
+		if (status & tps65217_irqs[i].interrupt) {
+			handle_nested_irq(irq_find_mapping(tps->irq_domain, i));
+			handled = true;
+		}
+	}
+
+	if (handled)
+		return IRQ_HANDLED;
+
+	return IRQ_NONE;
+}
+
+static int tps65217_irq_map(struct irq_domain *h, unsigned int virq,
+			irq_hw_number_t hw)
+{
+	struct tps65217 *tps = h->host_data;
+
+	irq_set_chip_data(virq, tps);
+	irq_set_chip_and_handler(virq, &tps65217_irq_chip, handle_edge_irq);
+	irq_set_nested_thread(virq, 1);
+	irq_set_parent(virq, tps->irq);
+	irq_set_noprobe(virq);
+
+	return 0;
+}
+
+static const struct irq_domain_ops tps65217_irq_domain_ops = {
+	.map = tps65217_irq_map,
+};
+
+static int tps65217_irq_init(struct tps65217 *tps, int irq)
+{
+	int ret;
+
+	mutex_init(&tps->irq_lock);
+	tps->irq = irq;
+
+	/* Mask all interrupt sources */
+	tps->irq_mask = (TPS65217_INT_RESERVEDM | TPS65217_INT_PBM
+			| TPS65217_INT_ACM | TPS65217_INT_USBM);
+	tps65217_reg_write(tps, TPS65217_REG_INT, tps->irq_mask,
+			TPS65217_PROTECT_NONE);
+
+	tps->irq_domain = irq_domain_add_linear(tps->dev->of_node,
+		TPS65217_NUM_IRQ, &tps65217_irq_domain_ops, tps);
+	if (!tps->irq_domain) {
+		dev_err(tps->dev, "Could not create IRQ domain\n");
+		return -ENOMEM;
+	}
+
+	ret = devm_request_threaded_irq(tps->dev, irq, NULL,
+					tps65217_irq_thread, IRQF_ONESHOT,
+					"tps65217-irq", tps);
+	if (ret) {
+		dev_err(tps->dev, "Failed to request IRQ %d: %d\n",
+			irq, ret);
+		return ret;
+	}
+
+	return 0;
+}
+
 /**
  * tps65217_reg_read: Read a single tps65217 register.
  *
@@ -149,11 +306,22 @@ int tps65217_clear_bits(struct tps65217 *tps, unsigned int reg,
 }
 EXPORT_SYMBOL_GPL(tps65217_clear_bits);
 
+static bool tps65217_volatile_reg(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case TPS65217_REG_INT:
+		return true;
+	default:
+		return false;
+	}
+}
+
 static const struct regmap_config tps65217_regmap_config = {
 	.reg_bits = 8,
 	.val_bits = 8,
 
 	.max_register = TPS65217_REG_MAX,
+	.volatile_reg = tps65217_volatile_reg,
 };
 
 static const struct of_device_id tps65217_of_match[] = {
@@ -205,8 +373,19 @@ static int tps65217_probe(struct i2c_client *client,
 		return ret;
 	}
 
+	if (client->irq) {
+		tps65217_irq_init(tps, client->irq);
+	} else {
+		int i;
+
+		/* Don't tell children about IRQ resources which won't fire */
+		for (i = 0; i < ARRAY_SIZE(tps65217s); i++)
+			tps65217s[i].num_resources = 0;
+	}
+
 	ret = devm_mfd_add_devices(tps->dev, -1, tps65217s,
-				   ARRAY_SIZE(tps65217s), NULL, 0, NULL);
+				   ARRAY_SIZE(tps65217s), NULL, 0,
+				   tps->irq_domain);
 	if (ret < 0) {
 		dev_err(tps->dev, "mfd_add_devices failed: %d\n", ret);
 		return ret;

include/linux/mfd/tps65217.h

@@ -73,6 +73,7 @@
 #define TPS65217_PPATH_AC_CURRENT_MASK	0x0C
 #define TPS65217_PPATH_USB_CURRENT_MASK	0x03
 
+#define TPS65217_INT_RESERVEDM		BIT(7)
 #define TPS65217_INT_PBM		BIT(6)
 #define TPS65217_INT_ACM		BIT(5)
 #define TPS65217_INT_USBM		BIT(4)
@@ -233,6 +234,13 @@ struct tps65217_bl_pdata {
 	int dft_brightness;
 };
 
+enum tps65217_irq_type {
+	TPS65217_IRQ_PB,
+	TPS65217_IRQ_AC,
+	TPS65217_IRQ_USB,
+	TPS65217_NUM_IRQ
+};
+
 /**
  * struct tps65217_board - packages regulator init data
  * @tps65217_regulator_data: regulator initialization values
@@ -258,6 +266,10 @@ struct tps65217 {
 	struct regulator_desc desc[TPS65217_NUM_REGULATOR];
 	struct regmap *regmap;
 	u8 *strobes;
+	struct irq_domain *irq_domain;
+	struct mutex irq_lock;
+	u8 irq_mask;
+	int irq;
 };
 
 static inline struct tps65217 *dev_to_tps65217(struct device *dev)