mfd: bd9576: Add IRQ support

BD9573 and BD9576 support set of "protection" interrupts for "fatal"
issues. Those lead to SOC reset as PMIC shuts the power outputs. Thus
there is no relevant IRQ handling for them.

Few "detection" interrupts were added to the BD9576 with the idea that
SOC could take some recovery-action before error gets unrecoverable.

Unfortunately the BD9576 interrupt logic was not re-evaluated. IRQs
are not designed to be properly acknowleged - and IRQ line is kept
active for whole duration of error condition (in comparison to
informing only about state change).

For above reason, do not consider missing IRQ as error.

Signed-off-by: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

1 files changed, 85 insertions, 5 deletions

diff --git a/drivers/mfd/rohm-bd9576.c b/drivers/mfd/rohm-bd9576.c
index 2dbda1f401e2..6661a27d69a8 100644
--- a/drivers/mfd/rohm-bd9576.c
+++ b/drivers/mfd/rohm-bd9576.c
@@ -17,14 +17,30 @@
 #include <linux/regmap.h>
 #include <linux/types.h>
 
+enum {
+	BD957X_REGULATOR_CELL,
+	BD957X_WDT_CELL,
+};
+
+/*
+ * Due to the BD9576MUF nasty IRQ behaiour we don't always populate IRQs.
+ * These will be added to regulator resources only if IRQ information for the
+ * PMIC is populated in device-tree.
+ */
+static const struct resource bd9576_regulator_irqs[] = {
+	DEFINE_RES_IRQ_NAMED(BD9576_INT_THERM, "bd9576-temp"),
+	DEFINE_RES_IRQ_NAMED(BD9576_INT_OVD, "bd9576-ovd"),
+	DEFINE_RES_IRQ_NAMED(BD9576_INT_UVD, "bd9576-uvd"),
+};
+
 static struct mfd_cell bd9573_mfd_cells[] = {
-	{ .name = "bd9573-regulator", },
-	{ .name = "bd9576-wdt", },
+	[BD957X_REGULATOR_CELL]	= { .name = "bd9573-regulator", },
+	[BD957X_WDT_CELL]	= { .name = "bd9576-wdt", },
 };
 
 static struct mfd_cell bd9576_mfd_cells[] = {
-	{ .name = "bd9576-regulator", },
-	{ .name = "bd9576-wdt", },
+	[BD957X_REGULATOR_CELL]	= { .name = "bd9576-regulator", },
+	[BD957X_WDT_CELL]	= { .name = "bd9576-wdt", },
 };
 
 static const struct regmap_range volatile_ranges[] = {
@@ -49,6 +65,29 @@ static struct regmap_config bd957x_regmap = {
 	.cache_type = REGCACHE_RBTREE,
 };
 
+static struct regmap_irq bd9576_irqs[] = {
+	REGMAP_IRQ_REG(BD9576_INT_THERM, 0, BD957X_MASK_INT_MAIN_THERM),
+	REGMAP_IRQ_REG(BD9576_INT_OVP, 0, BD957X_MASK_INT_MAIN_OVP),
+	REGMAP_IRQ_REG(BD9576_INT_SCP, 0, BD957X_MASK_INT_MAIN_SCP),
+	REGMAP_IRQ_REG(BD9576_INT_OCP, 0, BD957X_MASK_INT_MAIN_OCP),
+	REGMAP_IRQ_REG(BD9576_INT_OVD, 0, BD957X_MASK_INT_MAIN_OVD),
+	REGMAP_IRQ_REG(BD9576_INT_UVD, 0, BD957X_MASK_INT_MAIN_UVD),
+	REGMAP_IRQ_REG(BD9576_INT_UVP, 0, BD957X_MASK_INT_MAIN_UVP),
+	REGMAP_IRQ_REG(BD9576_INT_SYS, 0, BD957X_MASK_INT_MAIN_SYS),
+};
+
+static struct regmap_irq_chip bd9576_irq_chip = {
+	.name = "bd9576_irq",
+	.irqs = &bd9576_irqs[0],
+	.num_irqs = ARRAY_SIZE(bd9576_irqs),
+	.status_base = BD957X_REG_INT_MAIN_STAT,
+	.mask_base = BD957X_REG_INT_MAIN_MASK,
+	.ack_base = BD957X_REG_INT_MAIN_STAT,
+	.init_ack_masked = true,
+	.num_regs = 1,
+	.irq_reg_stride = 1,
+};
+
 static int bd957x_i2c_probe(struct i2c_client *i2c,
 			     const struct i2c_device_id *id)
 {
@@ -57,6 +96,8 @@ static int bd957x_i2c_probe(struct i2c_client *i2c,
 	struct mfd_cell *cells;
 	int num_cells;
 	unsigned long chip_type;
+	struct irq_domain *domain;
+	bool usable_irqs;
 
 	chip_type = (unsigned long)of_device_get_match_data(&i2c->dev);
 
@@ -64,10 +105,16 @@ static int bd957x_i2c_probe(struct i2c_client *i2c,
 	case ROHM_CHIP_TYPE_BD9576:
 		cells = bd9576_mfd_cells;
 		num_cells = ARRAY_SIZE(bd9576_mfd_cells);
+		usable_irqs = !!i2c->irq;
 		break;
 	case ROHM_CHIP_TYPE_BD9573:
 		cells = bd9573_mfd_cells;
 		num_cells = ARRAY_SIZE(bd9573_mfd_cells);
+		/*
+		 * BD9573 only supports fatal IRQs which we can not handle
+		 * because SoC is going to lose the power.
+		 */
+		usable_irqs = false;
 		break;
 	default:
 		dev_err(&i2c->dev, "Unknown device type");
@@ -80,8 +127,41 @@ static int bd957x_i2c_probe(struct i2c_client *i2c,
 		return PTR_ERR(regmap);
 	}
 
+	/*
+	 * BD9576 behaves badly. It kepts IRQ line asserted for the whole
+	 * duration of detected HW condition (like over temperature). So we
+	 * don't require IRQ to be populated.
+	 * If IRQ information is not given, then we mask all IRQs and do not
+	 * provide IRQ resources to regulator driver - which then just omits
+	 * the notifiers.
+	 */
+	if (usable_irqs) {
+		struct regmap_irq_chip_data *irq_data;
+		struct mfd_cell *regulators;
+
+		regulators = &bd9576_mfd_cells[BD957X_REGULATOR_CELL];
+		regulators->resources = bd9576_regulator_irqs;
+		regulators->num_resources = ARRAY_SIZE(bd9576_regulator_irqs);
+
+		ret = devm_regmap_add_irq_chip(&i2c->dev, regmap, i2c->irq,
+					       IRQF_ONESHOT, 0,
+					       &bd9576_irq_chip, &irq_data);
+		if (ret) {
+			dev_err(&i2c->dev, "Failed to add IRQ chip\n");
+			return ret;
+		}
+		domain = regmap_irq_get_domain(irq_data);
+	} else {
+		ret = regmap_update_bits(regmap, BD957X_REG_INT_MAIN_MASK,
+					 BD957X_MASK_INT_ALL,
+					 BD957X_MASK_INT_ALL);
+		if (ret)
+			return ret;
+		domain = NULL;
+	}
+
 	ret = devm_mfd_add_devices(&i2c->dev, PLATFORM_DEVID_AUTO, cells,
-				   num_cells, NULL, 0, NULL);
+				   num_cells, NULL, 0, domain);
 	if (ret)
 		dev_err(&i2c->dev, "Failed to create subdevices\n");