[RFC v11 0/4] PolarFire SoC GPIO interrupt support

[RFC v11 0/4] PolarFire SoC GPIO interrupt support

[Conor Dooley]

From: Conor Dooley <conor.dooley@microchip.com>

In 2024 I sent a v7 of adding support for the GPIOs on PolarFire SoC,
which relied on an irqchip driver for a mux sitting between the GPIO
controllers and the main interrupt controller on the chip:
https://lore.kernel.org/all/20240723-flatworm-cornflake-8023212f6584@wendy/

Some feedback I got from Thomas there ended up being a complete black
hole for time spent, and I never managed to make the change he wanted,
as a house of cards collapsed whenever I tried it. I eventually
abandoned my attempt to upstream the GPIO driver with interrupt support
and cut it out of the driver to make progress. I've been carrying what
Thomas deemed incorrect downstream since.

Recently Hervé upstreamed a patchset for a Renesas chip that deals with
a mux sitting between a GPIO controller and the platform interrupt
controller by way of interrupt-map. I saw the opportunity to copy what
he did, so have gone from an irqchip driver that read the mux setting
that firmware had configured, to trivial driver that reads the mux
configuration from devicetree and sets the hardware up to match.

This gets rid entirely of the irqchip driver, so resolves Thomas'
complaint, but I don't love how the GPIO side of things turned out quite
as much. The hardware has 41 interrupts but 70 GPIO lines. 38 of these
are 1:1, direct connections to a dedicated line on the interrupt
controller and 3 are shared.
With the parent mux driver, the GPIO driver's interrupt handler was only
called either for specific direct interrupt or for only the subset that
are fed into the shared interrupt for that controller. Without the
parent irqchip from mux driver, and using interrupt-map, I lost the
ability to use mux driver to selectively call the handler, so now the
GPIO controller attempts to handle interrupts on all lines.
Probably this is ultimately not a big deal, it just feels bad to do.

Going RFC here, since it's an entirely different approach. The version
number is a continuation from before, since the patchset linked above
got merged at v10 when I stripped the interrupt support.

The mux driver has moved from irqchip to soc, since that's where Hervé's
ended up.

Cheers,
Conor.

CC: Thomas Gleixner <tglx@linutronix.de>
CC: Herve Codina <herve.codina@bootlin.com>
CC: Conor Dooley <conor.dooley@microchip.com>
CC: Daire McNamara <daire.mcnamara@microchip.com>
CC: Rob Herring <robh@kernel.org>
CC: Krzysztof Kozlowski <krzk+dt@kernel.org>
CC: Paul Walmsley <pjw@kernel.org>
CC: Palmer Dabbelt <palmer@dabbelt.com>
CC: Albert Ou <aou@eecs.berkeley.edu>
CC: Alexandre Ghiti <alex@ghiti.fr>
CC: Linus Walleij <linusw@kernel.org>
CC: Bartosz Golaszewski <brgl@kernel.org>
CC: linux-riscv@lists.infradead.org
CC: devicetree@vger.kernel.org
CC: linux-kernel@vger.kernel.org
CC: linux-gpio@vger.kernel.org

Conor Dooley (4):
  gpio: mpfs: Add interrupt support
  dt-bindings: soc: microchip: document PolarFire SoC's gpio interrupt
    mux
  soc: microchip: add mpfs gpio interrupt mux driver
  riscv: dts: microchip: update mpfs gpio interrupts to better match the
    SoC

 .../soc/microchip/microchip,mpfs-irqmux.yaml  |  76 ++++++++
 .../microchip,mpfs-mss-top-sysreg.yaml        |   4 +
 MAINTAINERS                                   |   2 +-
 .../boot/dts/microchip/mpfs-beaglev-fire.dts  |  29 +++
 .../boot/dts/microchip/mpfs-disco-kit.dts     |  43 +++--
 .../dts/microchip/mpfs-icicle-kit-common.dtsi |  37 +++-
 .../boot/dts/microchip/mpfs-m100pfsevp.dts    |  41 +++--
 .../boot/dts/microchip/mpfs-polarberry.dts    |  29 +++
 .../riscv/boot/dts/microchip/mpfs-sev-kit.dts |  37 +++-
 .../riscv/boot/dts/microchip/mpfs-tysom-m.dts |  35 +++-
 arch/riscv/boot/dts/microchip/mpfs.dtsi       |  37 +++-
 drivers/gpio/Kconfig                          |   1 +
 drivers/gpio/gpio-mpfs.c                      | 125 ++++++++++++-
 drivers/soc/microchip/Kconfig                 |  11 ++
 drivers/soc/microchip/Makefile                |   1 +
 drivers/soc/microchip/mpfs-irqmux.c           | 167 ++++++++++++++++++
 16 files changed, 620 insertions(+), 55 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/soc/microchip/microchip,mpfs-irqmux.yaml
 create mode 100644 drivers/soc/microchip/mpfs-irqmux.c

-- 
2.51.0

[RFC v11 1/4] gpio: mpfs: Add interrupt support

[Conor Dooley]

From: Conor Dooley <conor.dooley@microchip.com>

Add support for interrupts to the PolarFire SoC GPIO driver. Each GPIO
has an independent interrupt that is wired to an interrupt mux that sits
between the controllers and the PLIC. The SoC has more GPIO lines than
connections from the mux to the PLIC, so some GPIOs must share PLIC
interrupts. The configuration is not static and is set at runtime,
conventionally by the platform's firmware. CoreGPIO, the version
intended for use in the FPGA fabric has two interrupt output ports, one
is IO_NUM bits wide, as is used in the hardened cores, and the other is
a single bit with all lines ORed together.

Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
---
Doing the chained thing kinda covers all the bases at the expense of the
"direct" mode interrupts that have a dedicated connection to the PLIC.
---
 drivers/gpio/Kconfig     |   1 +
 drivers/gpio/gpio-mpfs.c | 125 ++++++++++++++++++++++++++++++++++++++-
 2 files changed, 123 insertions(+), 3 deletions(-)

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index b45fb799e36c1..1d1239323f615 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -572,6 +572,7 @@ config GPIO_PL061
 config GPIO_POLARFIRE_SOC
 	bool "Microchip FPGA GPIO support"
 	select REGMAP_MMIO
+	select GPIOLIB_IRQCHIP
 	help
 	  Say yes here to support the GPIO controllers on Microchip FPGAs.
 
diff --git a/drivers/gpio/gpio-mpfs.c b/drivers/gpio/gpio-mpfs.c
index 9468795b96348..d19249dd0c87d 100644
--- a/drivers/gpio/gpio-mpfs.c
+++ b/drivers/gpio/gpio-mpfs.c
@@ -9,8 +9,9 @@
 #include <linux/device.h>
 #include <linux/errno.h>
 #include <linux/gpio/driver.h>
-#include <linux/init.h>
+#include <linux/interrupt.h>
 #include <linux/mod_devicetable.h>
+#include <linux/of_irq.h>
 #include <linux/platform_device.h>
 #include <linux/property.h>
 #include <linux/regmap.h>
@@ -18,7 +19,7 @@
 
 #define MPFS_GPIO_CTRL(i)		(0x4 * (i))
 #define MPFS_MAX_NUM_GPIO		32
-#define MPFS_GPIO_EN_INT		3
+#define MPFS_GPIO_EN_INT		BIT(3)
 #define MPFS_GPIO_EN_OUT_BUF		BIT(2)
 #define MPFS_GPIO_EN_IN			BIT(1)
 #define MPFS_GPIO_EN_OUT		BIT(0)
@@ -52,6 +53,7 @@ static const struct regmap_config mpfs_gpio_regmap_config = {
 	.reg_bits = 32,
 	.reg_stride = 4,
 	.val_bits = 32,
+	.use_raw_spinlock = true,
 };
 
 static int mpfs_gpio_direction_input(struct gpio_chip *gc, unsigned int gpio_index)
@@ -114,13 +116,97 @@ static int mpfs_gpio_set(struct gpio_chip *gc, unsigned int gpio_index, int valu
 	return ret;
 }
 
+static int mpfs_gpio_irq_set_type(struct irq_data *data, unsigned int type)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(data);
+	struct mpfs_gpio_chip *mpfs_gpio = gpiochip_get_data(gc);
+	int gpio_index = irqd_to_hwirq(data) % 32;
+	u32 interrupt_type;
+
+	switch (type) {
+	case IRQ_TYPE_EDGE_BOTH:
+		interrupt_type = MPFS_GPIO_TYPE_INT_EDGE_BOTH;
+		break;
+	case IRQ_TYPE_EDGE_FALLING:
+		interrupt_type = MPFS_GPIO_TYPE_INT_EDGE_NEG;
+		break;
+	case IRQ_TYPE_EDGE_RISING:
+		interrupt_type = MPFS_GPIO_TYPE_INT_EDGE_POS;
+		break;
+	case IRQ_TYPE_LEVEL_HIGH:
+		interrupt_type = MPFS_GPIO_TYPE_INT_LEVEL_HIGH;
+		break;
+	case IRQ_TYPE_LEVEL_LOW:
+		interrupt_type = MPFS_GPIO_TYPE_INT_LEVEL_LOW;
+		break;
+	}
+
+	regmap_update_bits(mpfs_gpio->regs, MPFS_GPIO_CTRL(gpio_index),
+			   MPFS_GPIO_TYPE_INT_MASK, interrupt_type);
+
+	return 0;
+}
+
+static void mpfs_gpio_irq_unmask(struct irq_data *data)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(data);
+	struct mpfs_gpio_chip *mpfs_gpio = gpiochip_get_data(gc);
+	int gpio_index = irqd_to_hwirq(data) % 32;
+
+	gpiochip_enable_irq(gc, gpio_index);
+	mpfs_gpio_direction_input(gc, gpio_index);
+	regmap_update_bits(mpfs_gpio->regs, MPFS_GPIO_CTRL(gpio_index),
+			     MPFS_GPIO_EN_INT, MPFS_GPIO_EN_INT);
+}
+
+static void mpfs_gpio_irq_mask(struct irq_data *data)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(data);
+	struct mpfs_gpio_chip *mpfs_gpio = gpiochip_get_data(gc);
+	int gpio_index = irqd_to_hwirq(data) % 32;
+
+	regmap_update_bits(mpfs_gpio->regs, MPFS_GPIO_CTRL(gpio_index),
+			   MPFS_GPIO_EN_INT, 0);
+	gpiochip_disable_irq(gc, gpio_index);
+}
+
+static const struct irq_chip mpfs_gpio_irqchip = {
+	.name = "MPFS GPIO",
+	.irq_set_type = mpfs_gpio_irq_set_type,
+	.irq_mask = mpfs_gpio_irq_mask,
+	.irq_unmask = mpfs_gpio_irq_unmask,
+	.flags = IRQCHIP_IMMUTABLE | IRQCHIP_MASK_ON_SUSPEND,
+	GPIOCHIP_IRQ_RESOURCE_HELPERS,
+};
+
+static irqreturn_t mpfs_gpio_irq_handler(int irq, void *data)
+{
+	struct mpfs_gpio_chip *mpfs_gpio = data;
+	unsigned int handled = 0;
+	unsigned long status;
+	u32 val;
+	int i;
+
+	regmap_read(mpfs_gpio->regs, MPFS_IRQ_REG, &val);
+	status = val;
+	for_each_set_bit(i, &status, MPFS_MAX_NUM_GPIO) {
+		regmap_write(mpfs_gpio->regs, MPFS_IRQ_REG, BIT(i));
+		generic_handle_domain_irq(mpfs_gpio->gc.irq.domain, i);
+		handled++;
+	}
+
+	return handled ? IRQ_HANDLED : IRQ_NONE;
+}
+
 static int mpfs_gpio_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
+	struct device_node *node = pdev->dev.of_node;
 	struct mpfs_gpio_chip *mpfs_gpio;
+	struct gpio_irq_chip *girq;
 	struct clk *clk;
 	void __iomem *base;
-	int ngpios;
+	int ngpios, nirqs, ret;
 
 	mpfs_gpio = devm_kzalloc(dev, sizeof(*mpfs_gpio), GFP_KERNEL);
 	if (!mpfs_gpio)
@@ -157,6 +243,39 @@ static int mpfs_gpio_probe(struct platform_device *pdev)
 	mpfs_gpio->gc.parent = dev;
 	mpfs_gpio->gc.owner = THIS_MODULE;
 
+	nirqs = of_irq_count(node);
+	if (nirqs > MPFS_MAX_NUM_GPIO)
+		return -ENXIO;
+
+	girq = &mpfs_gpio->gc.irq;
+	girq->num_parents = nirqs;
+
+	if (girq->num_parents) {
+		gpio_irq_chip_set_chip(girq, &mpfs_gpio_irqchip);
+
+		girq->parents = devm_kcalloc(&pdev->dev, girq->num_parents,
+					     sizeof(*girq->parents), GFP_KERNEL);
+		if (!girq->parents)
+			return -ENOMEM;
+
+		for (int i = 0; i < girq->num_parents; i++) {
+			ret = platform_get_irq(pdev, i);
+			if (ret < 0)
+				return ret;
+
+			girq->parents[i] = ret;
+			ret = devm_request_irq(dev, girq->parents[i], mpfs_gpio_irq_handler,
+					       IRQF_SHARED, NULL, mpfs_gpio);
+			if (ret)
+				return dev_err_probe(dev, ret,
+						     "failed to request irq for line %u\n",
+						     i);
+		}
+
+		girq->handler = handle_level_irq;
+		girq->default_type = IRQ_TYPE_NONE;
+	}
+
 	return devm_gpiochip_add_data(dev, &mpfs_gpio->gc, mpfs_gpio);
 }
 
-- 
2.51.0

[RFC v11 2/4] dt-bindings: soc: microchip: document PolarFire SoC's gpio interrupt mux

[Conor Dooley]

From: Conor Dooley <conor.dooley@microchip.com>

On PolarFire SoC there are more GPIO interrupts than there are interrupt
lines available on the PLIC, and a runtime configurable mux is used to
decide which interrupts are assigned direct connections to the PLIC &
which are relegated to sharing a line.

Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
---
 .../soc/microchip/microchip,mpfs-irqmux.yaml  | 76 +++++++++++++++++++
 .../microchip,mpfs-mss-top-sysreg.yaml        |  4 +
 2 files changed, 80 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/soc/microchip/microchip,mpfs-irqmux.yaml

diff --git a/Documentation/devicetree/bindings/soc/microchip/microchip,mpfs-irqmux.yaml b/Documentation/devicetree/bindings/soc/microchip/microchip,mpfs-irqmux.yaml
new file mode 100644
index 0000000000000..c8b0de9444dd6
--- /dev/null
+++ b/Documentation/devicetree/bindings/soc/microchip/microchip,mpfs-irqmux.yaml
@@ -0,0 +1,76 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/soc/microchip/microchip,mpfs-irqmux.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Microchip Polarfire SoC GPIO Interrupt Mux
+
+maintainers:
+  - Conor Dooley <conor.dooley@microchip.com>
+
+description: |
+  There are 3 GPIO controllers on this SoC, of which:
+  - GPIO controller 0 has 14 GPIOs
+  - GPIO controller 1 has 24 GPIOs
+  - GPIO controller 2 has 32 GPIOs
+
+  All GPIOs are capable of generating interrupts, for a total of 70.
+  There are only 41 IRQs available however, so a configurable mux is used to
+  ensure all GPIOs can be used for interrupt generation.
+  38 of the 41 interrupts are in what the documentation calls "direct mode",
+  as they provide an exclusive connection from a GPIO to the PLIC.
+  The 3 remaining interrupts are used to mux the interrupts which do not have
+  a exclusive connection, one for each GPIO controller.
+
+properties:
+  compatible:
+    const: microchip,mpfs-irqmux
+
+  reg:
+    maxItems: 1
+
+  "#address-cells":
+    const: 0
+
+  "#interrupt-cells":
+    const: 1
+
+  interrupt-map-mask:
+    items:
+      - const: 0x7f
+
+  interrupt-map:
+    description: |
+      Specifies the mapping from GPIO interrupt lines to plic interrupts.
+
+      The child interrupt number set in arrays items is computed using the
+      following formula:
+          gpio_bank * 32 + gpio_number
+      with:
+        - gpio_bank: The GPIO bank number
+            - 0 for GPIO0,
+            - 1 for GPIO1,
+            - 2 for GPIO2
+        - gpio_number: Number of the gpio in the bank (0..31)
+    maxItems: 70
+
+required:
+  - compatible
+  - reg
+  - "#address-cells"
+  - "#interrupt-cells"
+  - interrupt-map-mask
+  - interrupt-map
+
+additionalProperties: false
+
+examples:
+  - |
+    interrupt-controller@54 {
+        compatible = "microchip,mpfs-irqmux";
+        reg = <0x54 0x4>;
+        #address-cells = <0>;
+        #interrupt-cells = <1>;
+        interrupt-map-mask = <0xff>;
+    };
diff --git a/Documentation/devicetree/bindings/soc/microchip/microchip,mpfs-mss-top-sysreg.yaml b/Documentation/devicetree/bindings/soc/microchip/microchip,mpfs-mss-top-sysreg.yaml
index 44e4a50c31554..276d48ba15f01 100644
--- a/Documentation/devicetree/bindings/soc/microchip/microchip,mpfs-mss-top-sysreg.yaml
+++ b/Documentation/devicetree/bindings/soc/microchip/microchip,mpfs-mss-top-sysreg.yaml
@@ -38,6 +38,10 @@ properties:
       of PolarFire clock/reset IDs.
     const: 1
 
+  interrupt-controller@54:
+    type: object
+    $ref: /schemas/soc/microchip/microchip,mpfs-irqmux.yaml
+
   pinctrl@200:
     type: object
     $ref: /schemas/pinctrl/microchip,mpfs-pinctrl-iomux0.yaml
-- 
2.51.0

[RFC v11 3/4] soc: microchip: add mpfs gpio interrupt mux driver

[Conor Dooley]

From: Conor Dooley <conor.dooley@microchip.com>

On PolarFire SoC there are more GPIO interrupts than there are interrupt
lines available on the PLIC, and a runtime configurable mux is used to
decide which interrupts are assigned direct connections to the PLIC &
which are relegated to sharing a line.

Add a driver so that Linux can set the mux based on the interrupt
mapping in the devicetree.

Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
---
 MAINTAINERS                         |   2 +-
 drivers/soc/microchip/Kconfig       |  11 ++
 drivers/soc/microchip/Makefile      |   1 +
 drivers/soc/microchip/mpfs-irqmux.c | 167 ++++++++++++++++++++++++++++
 4 files changed, 180 insertions(+), 1 deletion(-)
 create mode 100644 drivers/soc/microchip/mpfs-irqmux.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 4044b28ca1818..55ed37ee53af0 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -22691,7 +22691,7 @@ F:	Documentation/devicetree/bindings/pinctrl/microchip,mpfs-pinctrl-mssio.yaml
 F:	Documentation/devicetree/bindings/pinctrl/microchip,pic64gx-pinctrl-gpio2.yaml
 F:	Documentation/devicetree/bindings/pwm/microchip,corepwm.yaml
 F:	Documentation/devicetree/bindings/riscv/microchip.yaml
-F:	Documentation/devicetree/bindings/soc/microchip/microchip,mpfs-sys-controller.yaml
+F:	Documentation/devicetree/bindings/soc/microchip/microchip,mpfs*.yaml
 F:	Documentation/devicetree/bindings/spi/microchip,mpfs-spi.yaml
 F:	Documentation/devicetree/bindings/usb/microchip,mpfs-musb.yaml
 F:	arch/riscv/boot/dts/microchip/
diff --git a/drivers/soc/microchip/Kconfig b/drivers/soc/microchip/Kconfig
index bcf5546025610..7131f1b52d1bc 100644
--- a/drivers/soc/microchip/Kconfig
+++ b/drivers/soc/microchip/Kconfig
@@ -1,3 +1,14 @@
+config POLARFIRE_SOC_IRQ_MUX
+	bool "Microchip PolarFire SoC's GPIO IRQ Mux"
+	depends on ARCH_MICROCHIP
+	select REGMAP
+	select REGMAP_MMIO
+	default y
+	help
+	  Support for the interrupt mux on Polarfire SoC. It sits between
+	  the GPIO controllers and the PLIC, as only 35 interrupts are shared
+	  between 3 GPIO controllers with 32 interrupts each.
+
 config POLARFIRE_SOC_SYS_CTRL
 	tristate "Microchip PolarFire SoC (MPFS) system controller support"
 	depends on POLARFIRE_SOC_MAILBOX
diff --git a/drivers/soc/microchip/Makefile b/drivers/soc/microchip/Makefile
index 1a3a1594b089b..55775db45ee76 100644
--- a/drivers/soc/microchip/Makefile
+++ b/drivers/soc/microchip/Makefile
@@ -1,2 +1,3 @@
+obj-$(CONFIG_POLARFIRE_SOC_IRQ_MUX)	+= mpfs-irqmux.o
 obj-$(CONFIG_POLARFIRE_SOC_SYS_CTRL)	+= mpfs-sys-controller.o
 obj-$(CONFIG_POLARFIRE_SOC_SYSCONS)	+= mpfs-control-scb.o mpfs-mss-top-sysreg.o
diff --git a/drivers/soc/microchip/mpfs-irqmux.c b/drivers/soc/microchip/mpfs-irqmux.c
new file mode 100644
index 0000000000000..76c1afa1fe1c4
--- /dev/null
+++ b/drivers/soc/microchip/mpfs-irqmux.c
@@ -0,0 +1,167 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Largely copied from rzn1_irqmux.c
+ */
+
+#include <linux/bitmap.h>
+#include <linux/bitops.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+#define MPFS_IRQMUX_CR		0x54
+#define MPFS_IRQMUX_NUM_OUTPUTS	70
+
+static int mpfs_irqmux_is_direct_mode(struct device *dev,
+				      const struct of_phandle_args *parent_args)
+{
+	if (parent_args->args_count != 1) {
+		dev_err(dev, "Invalid interrupt-map item\n");
+		return -EINVAL;
+	}
+
+	if (parent_args->args[0] < 13 || parent_args->args[0] > 53) {
+		dev_err(dev, "Invalid interrupt %u\n", parent_args->args[0]);
+		return -EINVAL;
+	}
+
+	if (parent_args->args[0] > 50)
+		return 0;
+
+	return 1;
+}
+
+static int mpfs_irqmux_probe(struct platform_device *pdev)
+{
+	DECLARE_BITMAP(line_done, MPFS_IRQMUX_NUM_OUTPUTS) = {};
+	struct device *dev = &pdev->dev;
+	struct device_node *np = dev->of_node;
+	struct of_imap_parser imap_parser;
+	struct of_imap_item imap_item;
+	struct regmap *regmap;
+	int ret, direct_mode, line, controller, gpio;
+	u32 tmp, val = 0, old;
+
+	regmap = device_node_to_regmap(pdev->dev.parent->of_node);
+	if (IS_ERR(regmap))
+		return dev_err_probe(dev, PTR_ERR(regmap), "Failed to find syscon regmap\n");
+
+	/* We support only #interrupt-cells = <1> and #address-cells = <0> */
+	ret = of_property_read_u32(np, "#interrupt-cells", &tmp);
+	if (ret)
+		return ret;
+	if (tmp != 1)
+		return -EINVAL;
+
+	ret = of_property_read_u32(np, "#address-cells", &tmp);
+	if (ret)
+		return ret;
+	if (tmp != 0)
+		return -EINVAL;
+
+	ret = of_imap_parser_init(&imap_parser, np, &imap_item);
+	if (ret)
+		return ret;
+
+	for_each_of_imap_item(&imap_parser, &imap_item) {
+
+		direct_mode = mpfs_irqmux_is_direct_mode(dev, &imap_item.parent_args);
+		if (direct_mode < 0) {
+			of_node_put(imap_item.parent_args.np);
+			return direct_mode;
+		}
+
+		line = imap_item.child_imap[0];
+		gpio = line % 32;
+		controller = line / 32;
+
+		if (controller > 2) {
+			of_node_put(imap_item.parent_args.np);
+			dev_err(dev, "child interrupt number too large: %d\n", line);
+			return -EINVAL;
+		}
+
+		if (test_and_set_bit(line, line_done)) {
+			of_node_put(imap_item.parent_args.np);
+			dev_err(dev, "Mux output line %d already defined in interrupt-map\n",
+				line);
+			return -EINVAL;
+		}
+
+		/*
+		 * There are 41 interrupts assigned to GPIOs, of which 38 are "direct". Since the
+		 * mux has 32 bits only, 6 of these exclusive/"direct" interrupts remain. These
+		 * are used by GPIO controller 1's lines 18 to 23. Nothing needs to be done
+		 * for these interrupts.
+		 */
+		if (controller == 1 && gpio >= 18)
+			continue;
+
+		/*
+		 * The mux has a single register, where bits 0 to 13 mux between GPIO controller
+		 * 1's 14 GPIOs and GPIO controller 2's first 14 GPIOs. The remaining bits mux
+		 * between the first 18 GPIOs of controller 1 and the last 18 GPIOS of
+		 * controller 2. If a bit in the mux's control register is set, the
+		 * corresponding interrupt line for GPIO controller 0 or 1 will be put in
+		 * "non-direct" mode. If cleared, the "fabric" controller's will.
+		 *
+		 * Register layout:
+		 *    GPIO 1 interrupt line 17 | mux bit 31 | GPIO 2 interrupt line 31
+		 *    ...                      | ...        | ...
+		 *    ...                      | ...        | ...
+		 *    GPIO 1 interrupt line  0 | mux bit 14 | GPIO 2 interrupt line 14
+		 *    GPIO 0 interrupt line 13 | mux bit 13 | GPIO 2 interrupt line 13
+		 *    ...                      | ...        | ...
+		 *    ...                      | ...        | ...
+		 *    GPIO 0 interrupt line  0 | mux bit  0 | GPIO 2 interrupt line  0
+		 *
+		 * As the binding mandates 70 items, one for each GPIO line, there's no need to
+		 * handle anything for GPIO controller 2, since the bit will be set for the
+		 * corresponding line in GPIO controller 0 or 1.
+		 */
+		if (controller == 2)
+			continue;
+
+		/*
+		 * If in direct mode, the bit is cleared, nothing needs to be done as val is zero
+		 * initialised and that's the direct mode setting for GPIO controller 0 and 1.
+		 */
+		if (direct_mode)
+			continue;
+
+		if (controller == 0)
+			val |= 1U << gpio;
+		else
+			val |= 1U << (gpio + 14);
+	}
+
+	regmap_read(regmap, MPFS_IRQMUX_CR, &old);
+	regmap_write(regmap, MPFS_IRQMUX_CR, val);
+
+	if (val != old)
+		dev_info(dev, "firmware mux setting of 0x%x overwritten to 0x%x\n", old, val);
+
+	return 0;
+}
+
+static const struct of_device_id mpfs_irqmux_of_match[] = {
+	{ .compatible = "microchip,mpfs-irqmux", },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, mpfs_irqmux_of_match);
+
+static struct platform_driver mpfs_irqmux_driver = {
+	.probe = mpfs_irqmux_probe,
+	.driver = {
+		.name = "mpfs_irqmux",
+		.of_match_table = mpfs_irqmux_of_match,
+	},
+};
+module_platform_driver(mpfs_irqmux_driver);
+
+MODULE_AUTHOR("Conor Dooley <conor.dooley@microchip.com>");
+MODULE_DESCRIPTION("Polarfire SoC interrupt mux driver");
+MODULE_LICENSE("GPL");
-- 
2.51.0

[RFC v11 4/4] riscv: dts: microchip: update mpfs gpio interrupts to better match the SoC

[Conor Dooley]

From: Conor Dooley <conor.dooley@microchip.com>

There are 3 GPIO controllers on this SoC, of which:
- GPIO controller 0 has 14 GPIOs
- GPIO controller 1 has 24 GPIOs
- GPIO controller 2 has 32 GPIOs

All GPIOs are capable of generating interrupts, for a total of 70.
There are only 41 IRQs available however, so a configurable mux is used
to ensure all GPIOs can be used for interrupt generation.
38 of the 41 interrupts are in what the documentation calls "direct
mode", as they provide an exclusive connection from a GPIO to the PLIC.
The 3 remaining interrupts are used to mux the interrupts which do not
have a exclusive connection, one for each GPIO controller.

The mux was overlooked when the bindings and driver were originally
written for the GPIO controllers on Polarfire SoC, and the interrupts
property in the GPIO nodes used to try and convey what the mapping was.
Instead, the mux should be a device in its own right, and the GPIO
controllers should be connected to it, rather than to the PLIC.
Now that a binding exists for that mux, fix the inaccurate description
of the interrupt controller hierarchy.

GPIO controllers 0 and 1 do not have all 32 possible GPIO lines, so
ngpios needs to be set to match the number of lines/interrupts.

The m100pfsevp has conflicting interrupt mappings for controllers 0 and
2, as they cannot both be using an interrupt in "direct mode" at the
same time, so the default replaces this impossible configuration.

Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
---
 .../boot/dts/microchip/mpfs-beaglev-fire.dts  | 29 +++++++++++++
 .../boot/dts/microchip/mpfs-disco-kit.dts     | 43 +++++++++++++------
 .../dts/microchip/mpfs-icicle-kit-common.dtsi | 37 ++++++++++++----
 .../boot/dts/microchip/mpfs-m100pfsevp.dts    | 41 ++++++++++++------
 .../boot/dts/microchip/mpfs-polarberry.dts    | 29 +++++++++++++
 .../riscv/boot/dts/microchip/mpfs-sev-kit.dts | 37 ++++++++++++----
 .../riscv/boot/dts/microchip/mpfs-tysom-m.dts | 35 ++++++++++++---
 arch/riscv/boot/dts/microchip/mpfs.dtsi       | 37 ++++++++++++++--
 8 files changed, 237 insertions(+), 51 deletions(-)

diff --git a/arch/riscv/boot/dts/microchip/mpfs-beaglev-fire.dts b/arch/riscv/boot/dts/microchip/mpfs-beaglev-fire.dts
index 73afa2d26bb61..7e6449ba91b6a 100644
--- a/arch/riscv/boot/dts/microchip/mpfs-beaglev-fire.dts
+++ b/arch/riscv/boot/dts/microchip/mpfs-beaglev-fire.dts
@@ -163,6 +163,35 @@ imx219_0: endpoint {
 	};
 };
 
+&irqmux {
+	interrupt-map = <0 &plic 13>, <1 &plic 14>, <2 &plic 15>,
+			<3 &plic 16>, <4 &plic 17>, <5 &plic 18>,
+			<6 &plic 19>, <7 &plic 20>, <8 &plic 21>,
+			<9 &plic 22>, <10 &plic 23>, <11 &plic 24>,
+			<12 &plic 25>, <13 &plic 26>,
+
+			<32 &plic 27>, <33 &plic 28>, <34 &plic 29>,
+			<35 &plic 30>, <36 &plic 31>, <37 &plic 32>,
+			<38 &plic 33>, <39 &plic 34>, <40 &plic 35>,
+			<41 &plic 36>, <42 &plic 37>, <43 &plic 38>,
+			<44 &plic 39>, <45 &plic 40>, <46 &plic 41>,
+			<47 &plic 42>, <48 &plic 43>, <49 &plic 44>,
+			<50 &plic 45>, <51 &plic 46>, <52 &plic 47>,
+			<53 &plic 48>, <54 &plic 49>, <55 &plic 50>,
+
+			<64 &plic 53>, <65 &plic 53>, <66 &plic 53>,
+			<67 &plic 53>, <68 &plic 53>, <69 &plic 53>,
+			<70 &plic 53>, <71 &plic 53>, <72 &plic 53>,
+			<73 &plic 53>, <74 &plic 53>, <75 &plic 53>,
+			<76 &plic 53>, <77 &plic 53>, <78 &plic 53>,
+			<79 &plic 53>, <80 &plic 53>, <81 &plic 53>,
+			<82 &plic 53>, <83 &plic 53>, <84 &plic 53>,
+			<85 &plic 53>, <86 &plic 53>, <87 &plic 53>,
+			<88 &plic 53>, <89 &plic 53>, <90 &plic 53>,
+			<91 &plic 53>, <92 &plic 53>, <93 &plic 53>,
+			<94 &plic 53>, <95 &plic 53>;
+};
+
 &mac0 {
 	status = "okay";
 	phy-mode = "sgmii";
diff --git a/arch/riscv/boot/dts/microchip/mpfs-disco-kit.dts b/arch/riscv/boot/dts/microchip/mpfs-disco-kit.dts
index c068b9bb5bfdf..f769c9d5d7b47 100644
--- a/arch/riscv/boot/dts/microchip/mpfs-disco-kit.dts
+++ b/arch/riscv/boot/dts/microchip/mpfs-disco-kit.dts
@@ -97,24 +97,10 @@ &core_pwm0 {
 };
 
 &gpio1 {
-	interrupts = <27>, <28>, <29>, <30>,
-		     <31>, <32>, <33>, <47>,
-		     <35>, <36>, <37>, <38>,
-		     <39>, <40>, <41>, <42>,
-		     <43>, <44>, <45>, <46>,
-		     <47>, <48>, <49>, <50>;
 	status = "okay";
 };
 
 &gpio2 {
-	interrupts = <53>, <53>, <53>, <53>,
-		     <53>, <53>, <53>, <53>,
-		     <53>, <53>, <53>, <53>,
-		     <53>, <53>, <53>, <53>,
-		     <53>, <53>, <53>, <53>,
-		     <53>, <53>, <53>, <53>,
-		     <53>, <53>, <53>, <53>,
-		     <53>, <53>, <53>, <53>;
 	status = "okay";
 };
 
@@ -130,6 +116,35 @@ &ihc {
 	status = "okay";
 };
 
+&irqmux {
+	interrupt-map = <0 &plic 13>, <1 &plic 14>, <2 &plic 15>,
+			<3 &plic 16>, <4 &plic 17>, <5 &plic 18>,
+			<6 &plic 19>, <7 &plic 20>, <8 &plic 21>,
+			<9 &plic 22>, <10 &plic 23>, <11 &plic 24>,
+			<12 &plic 25>, <13 &plic 26>,
+
+			<32 &plic 27>, <33 &plic 28>, <34 &plic 29>,
+			<35 &plic 30>, <36 &plic 31>, <37 &plic 32>,
+			<38 &plic 33>, <39 &plic 34>, <40 &plic 35>,
+			<41 &plic 36>, <42 &plic 37>, <43 &plic 38>,
+			<44 &plic 39>, <45 &plic 40>, <46 &plic 41>,
+			<47 &plic 42>, <48 &plic 43>, <49 &plic 44>,
+			<50 &plic 45>, <51 &plic 46>, <52 &plic 47>,
+			<53 &plic 48>, <54 &plic 49>, <55 &plic 50>,
+
+			<64 &plic 53>, <65 &plic 53>, <66 &plic 53>,
+			<67 &plic 53>, <68 &plic 53>, <69 &plic 53>,
+			<70 &plic 53>, <71 &plic 53>, <72 &plic 53>,
+			<73 &plic 53>, <74 &plic 53>, <75 &plic 53>,
+			<76 &plic 53>, <77 &plic 53>, <78 &plic 53>,
+			<79 &plic 53>, <80 &plic 53>, <81 &plic 53>,
+			<82 &plic 53>, <83 &plic 53>, <84 &plic 53>,
+			<85 &plic 53>, <86 &plic 53>, <87 &plic 53>,
+			<88 &plic 53>, <89 &plic 53>, <90 &plic 53>,
+			<91 &plic 53>, <92 &plic 53>, <93 &plic 53>,
+			<94 &plic 53>, <95 &plic 53>;
+};
+
 &mac0 {
 	phy-mode = "sgmii";
 	phy-handle = <&phy0>;
diff --git a/arch/riscv/boot/dts/microchip/mpfs-icicle-kit-common.dtsi b/arch/riscv/boot/dts/microchip/mpfs-icicle-kit-common.dtsi
index e01a216e6c3a8..e25edc5f3b451 100644
--- a/arch/riscv/boot/dts/microchip/mpfs-icicle-kit-common.dtsi
+++ b/arch/riscv/boot/dts/microchip/mpfs-icicle-kit-common.dtsi
@@ -77,14 +77,6 @@ &core_pwm0 {
 };
 
 &gpio2 {
-	interrupts = <53>, <53>, <53>, <53>,
-		     <53>, <53>, <53>, <53>,
-		     <53>, <53>, <53>, <53>,
-		     <53>, <53>, <53>, <53>,
-		     <53>, <53>, <53>, <53>,
-		     <53>, <53>, <53>, <53>,
-		     <53>, <53>, <53>, <53>,
-		     <53>, <53>, <53>, <53>;
 	status = "okay";
 };
 
@@ -136,6 +128,35 @@ &ihc {
 	status = "okay";
 };
 
+&irqmux {
+	interrupt-map = <0 &plic 13>, <1 &plic 14>, <2 &plic 15>,
+			<3 &plic 16>, <4 &plic 17>, <5 &plic 18>,
+			<6 &plic 19>, <7 &plic 20>, <8 &plic 21>,
+			<9 &plic 22>, <10 &plic 23>, <11 &plic 24>,
+			<12 &plic 25>, <13 &plic 26>,
+
+			<32 &plic 27>, <33 &plic 28>, <34 &plic 29>,
+			<35 &plic 30>, <36 &plic 31>, <37 &plic 32>,
+			<38 &plic 33>, <39 &plic 34>, <40 &plic 35>,
+			<41 &plic 36>, <42 &plic 37>, <43 &plic 38>,
+			<44 &plic 39>, <45 &plic 40>, <46 &plic 41>,
+			<47 &plic 42>, <48 &plic 43>, <49 &plic 44>,
+			<50 &plic 45>, <51 &plic 46>, <52 &plic 47>,
+			<53 &plic 48>, <54 &plic 49>, <55 &plic 50>,
+
+			<64 &plic 53>, <65 &plic 53>, <66 &plic 53>,
+			<67 &plic 53>, <68 &plic 53>, <69 &plic 53>,
+			<70 &plic 53>, <71 &plic 53>, <72 &plic 53>,
+			<73 &plic 53>, <74 &plic 53>, <75 &plic 53>,
+			<76 &plic 53>, <77 &plic 53>, <78 &plic 53>,
+			<79 &plic 53>, <80 &plic 53>, <81 &plic 53>,
+			<82 &plic 53>, <83 &plic 53>, <84 &plic 53>,
+			<85 &plic 53>, <86 &plic 53>, <87 &plic 53>,
+			<88 &plic 53>, <89 &plic 53>, <90 &plic 53>,
+			<91 &plic 53>, <92 &plic 53>, <93 &plic 53>,
+			<94 &plic 53>, <95 &plic 53>;
+};
+
 &mac0 {
 	phy-mode = "sgmii";
 	phy-handle = <&phy0>;
diff --git a/arch/riscv/boot/dts/microchip/mpfs-m100pfsevp.dts b/arch/riscv/boot/dts/microchip/mpfs-m100pfsevp.dts
index a8d623ee9fa4c..86234968df486 100644
--- a/arch/riscv/boot/dts/microchip/mpfs-m100pfsevp.dts
+++ b/arch/riscv/boot/dts/microchip/mpfs-m100pfsevp.dts
@@ -52,11 +52,36 @@ &i2c1 {
 	status = "okay";
 };
 
+&irqmux {
+	interrupt-map = <0 &plic 13>, <1 &plic 14>, <2 &plic 15>,
+			<3 &plic 16>, <4 &plic 17>, <5 &plic 18>,
+			<6 &plic 19>, <7 &plic 20>, <8 &plic 21>,
+			<9 &plic 22>, <10 &plic 23>, <11 &plic 24>,
+			<12 &plic 25>, <13 &plic 26>,
+
+			<32 &plic 27>, <33 &plic 28>, <34 &plic 29>,
+			<35 &plic 30>, <36 &plic 31>, <37 &plic 32>,
+			<38 &plic 33>, <39 &plic 34>, <40 &plic 35>,
+			<41 &plic 36>, <42 &plic 37>, <43 &plic 38>,
+			<44 &plic 39>, <45 &plic 40>, <46 &plic 41>,
+			<47 &plic 42>, <48 &plic 43>, <49 &plic 44>,
+			<50 &plic 45>, <51 &plic 46>, <52 &plic 47>,
+			<53 &plic 48>, <54 &plic 49>, <55 &plic 50>,
+
+			<64 &plic 53>, <65 &plic 53>, <66 &plic 53>,
+			<67 &plic 53>, <68 &plic 53>, <69 &plic 53>,
+			<70 &plic 53>, <71 &plic 53>, <72 &plic 53>,
+			<73 &plic 53>, <74 &plic 53>, <75 &plic 53>,
+			<76 &plic 53>, <77 &plic 53>, <78 &plic 53>,
+			<79 &plic 53>, <80 &plic 53>, <81 &plic 53>,
+			<82 &plic 53>, <83 &plic 53>, <84 &plic 53>,
+			<85 &plic 53>, <86 &plic 53>, <87 &plic 53>,
+			<88 &plic 53>, <89 &plic 53>, <90 &plic 53>,
+			<91 &plic 53>, <92 &plic 53>, <93 &plic 53>,
+			<94 &plic 53>, <95 &plic 53>;
+};
+
 &gpio0 {
-	interrupts = <13>, <14>, <15>, <16>,
-		     <17>, <18>, <19>, <20>,
-		     <21>, <22>, <23>, <24>,
-		     <25>, <26>;
 	ngpios = <14>;
 	status = "okay";
 
@@ -75,14 +100,6 @@ mmc-sel-hog {
 };
 
 &gpio2 {
-	interrupts = <13>, <14>, <15>, <16>,
-		     <17>, <18>, <19>, <20>,
-		     <21>, <22>, <23>, <24>,
-		     <25>, <26>, <27>, <28>,
-		     <29>, <30>, <31>, <32>,
-		     <33>, <34>, <35>, <36>,
-		     <37>, <38>, <39>, <40>,
-		     <41>, <42>, <43>, <44>;
 	status = "okay";
 };
 
diff --git a/arch/riscv/boot/dts/microchip/mpfs-polarberry.dts b/arch/riscv/boot/dts/microchip/mpfs-polarberry.dts
index ea0808ab10425..510d59153cd07 100644
--- a/arch/riscv/boot/dts/microchip/mpfs-polarberry.dts
+++ b/arch/riscv/boot/dts/microchip/mpfs-polarberry.dts
@@ -30,6 +30,35 @@ ddrc_cache_hi: memory@1000000000 {
 	};
 };
 
+&irqmux {
+	interrupt-map = <0 &plic 13>, <1 &plic 14>, <2 &plic 15>,
+			<3 &plic 16>, <4 &plic 17>, <5 &plic 18>,
+			<6 &plic 19>, <7 &plic 20>, <8 &plic 21>,
+			<9 &plic 22>, <10 &plic 23>, <11 &plic 24>,
+			<12 &plic 25>, <13 &plic 26>,
+
+			<32 &plic 27>, <33 &plic 28>, <34 &plic 29>,
+			<35 &plic 30>, <36 &plic 31>, <37 &plic 32>,
+			<38 &plic 33>, <39 &plic 34>, <40 &plic 35>,
+			<41 &plic 36>, <42 &plic 37>, <43 &plic 38>,
+			<44 &plic 39>, <45 &plic 40>, <46 &plic 41>,
+			<47 &plic 42>, <48 &plic 43>, <49 &plic 44>,
+			<50 &plic 45>, <51 &plic 46>, <52 &plic 47>,
+			<53 &plic 48>, <54 &plic 49>, <55 &plic 50>,
+
+			<64 &plic 53>, <65 &plic 53>, <66 &plic 53>,
+			<67 &plic 53>, <68 &plic 53>, <69 &plic 53>,
+			<70 &plic 53>, <71 &plic 53>, <72 &plic 53>,
+			<73 &plic 53>, <74 &plic 53>, <75 &plic 53>,
+			<76 &plic 53>, <77 &plic 53>, <78 &plic 53>,
+			<79 &plic 53>, <80 &plic 53>, <81 &plic 53>,
+			<82 &plic 53>, <83 &plic 53>, <84 &plic 53>,
+			<85 &plic 53>, <86 &plic 53>, <87 &plic 53>,
+			<88 &plic 53>, <89 &plic 53>, <90 &plic 53>,
+			<91 &plic 53>, <92 &plic 53>, <93 &plic 53>,
+			<94 &plic 53>, <95 &plic 53>;
+};
+
 /*
  * phy0 is connected to mac0, but the port itself is on the (optional) carrier
  * board.
diff --git a/arch/riscv/boot/dts/microchip/mpfs-sev-kit.dts b/arch/riscv/boot/dts/microchip/mpfs-sev-kit.dts
index f9a8905794383..8f1908a105671 100644
--- a/arch/riscv/boot/dts/microchip/mpfs-sev-kit.dts
+++ b/arch/riscv/boot/dts/microchip/mpfs-sev-kit.dts
@@ -56,15 +56,36 @@ &i2c0 {
 	status = "okay";
 };
 
+&irqmux {
+	interrupt-map = <0 &plic 13>, <1 &plic 14>, <2 &plic 15>,
+			<3 &plic 16>, <4 &plic 17>, <5 &plic 18>,
+			<6 &plic 19>, <7 &plic 20>, <8 &plic 21>,
+			<9 &plic 22>, <10 &plic 23>, <11 &plic 24>,
+			<12 &plic 25>, <13 &plic 26>,
+
+			<32 &plic 27>, <33 &plic 28>, <34 &plic 29>,
+			<35 &plic 30>, <36 &plic 31>, <37 &plic 32>,
+			<38 &plic 33>, <39 &plic 34>, <40 &plic 35>,
+			<41 &plic 36>, <42 &plic 37>, <43 &plic 38>,
+			<44 &plic 39>, <45 &plic 40>, <46 &plic 41>,
+			<47 &plic 42>, <48 &plic 43>, <49 &plic 44>,
+			<50 &plic 45>, <51 &plic 46>, <52 &plic 47>,
+			<53 &plic 48>, <54 &plic 49>, <55 &plic 50>,
+
+			<64 &plic 53>, <65 &plic 53>, <66 &plic 53>,
+			<67 &plic 53>, <68 &plic 53>, <69 &plic 53>,
+			<70 &plic 53>, <71 &plic 53>, <72 &plic 53>,
+			<73 &plic 53>, <74 &plic 53>, <75 &plic 53>,
+			<76 &plic 53>, <77 &plic 53>, <78 &plic 53>,
+			<79 &plic 53>, <80 &plic 53>, <81 &plic 53>,
+			<82 &plic 53>, <83 &plic 53>, <84 &plic 53>,
+			<85 &plic 53>, <86 &plic 53>, <87 &plic 53>,
+			<88 &plic 53>, <89 &plic 53>, <90 &plic 53>,
+			<91 &plic 53>, <92 &plic 53>, <93 &plic 53>,
+			<94 &plic 53>, <95 &plic 53>;
+};
+
 &gpio2 {
-	interrupts = <53>, <53>, <53>, <53>,
-		     <53>, <53>, <53>, <53>,
-		     <53>, <53>, <53>, <53>,
-		     <53>, <53>, <53>, <53>,
-		     <53>, <53>, <53>, <53>,
-		     <53>, <53>, <53>, <53>,
-		     <53>, <53>, <53>, <53>,
-		     <53>, <53>, <53>, <53>;
 	status = "okay";
 };
 
diff --git a/arch/riscv/boot/dts/microchip/mpfs-tysom-m.dts b/arch/riscv/boot/dts/microchip/mpfs-tysom-m.dts
index d1120f5f2c015..bc15530a2979b 100644
--- a/arch/riscv/boot/dts/microchip/mpfs-tysom-m.dts
+++ b/arch/riscv/boot/dts/microchip/mpfs-tysom-m.dts
@@ -69,13 +69,36 @@ hwmon: hwmon@45 {
 	};
 };
 
+&irqmux {
+	interrupt-map = <0 &plic 13>, <1 &plic 14>, <2 &plic 15>,
+			<3 &plic 16>, <4 &plic 17>, <5 &plic 18>,
+			<6 &plic 19>, <7 &plic 20>, <8 &plic 21>,
+			<9 &plic 22>, <10 &plic 23>, <11 &plic 24>,
+			<12 &plic 25>, <13 &plic 26>,
+
+			<32 &plic 27>, <33 &plic 28>, <34 &plic 29>,
+			<35 &plic 30>, <36 &plic 31>, <37 &plic 32>,
+			<38 &plic 33>, <39 &plic 34>, <40 &plic 35>,
+			<41 &plic 36>, <42 &plic 37>, <43 &plic 38>,
+			<44 &plic 39>, <45 &plic 40>, <46 &plic 41>,
+			<47 &plic 42>, <48 &plic 43>, <49 &plic 44>,
+			<50 &plic 45>, <51 &plic 46>, <52 &plic 47>,
+			<53 &plic 48>, <54 &plic 49>, <55 &plic 50>,
+
+			<64 &plic 53>, <65 &plic 53>, <66 &plic 53>,
+			<67 &plic 53>, <68 &plic 53>, <69 &plic 53>,
+			<70 &plic 53>, <71 &plic 53>, <72 &plic 53>,
+			<73 &plic 53>, <74 &plic 53>, <75 &plic 53>,
+			<76 &plic 53>, <77 &plic 53>, <78 &plic 53>,
+			<79 &plic 53>, <80 &plic 53>, <81 &plic 53>,
+			<82 &plic 53>, <83 &plic 53>, <84 &plic 53>,
+			<85 &plic 53>, <86 &plic 53>, <87 &plic 53>,
+			<88 &plic 53>, <89 &plic 53>, <90 &plic 53>,
+			<91 &plic 53>, <92 &plic 53>, <93 &plic 53>,
+			<94 &plic 53>, <95 &plic 53>;
+};
+
 &gpio1 {
-	interrupts = <27>, <28>, <29>, <30>,
-		     <31>, <32>, <33>, <47>,
-		     <35>, <36>, <37>, <38>,
-		     <39>, <40>, <41>, <42>,
-		     <43>, <44>, <45>, <46>,
-		     <47>, <48>, <49>, <50>;
 	status = "okay";
 };
 
diff --git a/arch/riscv/boot/dts/microchip/mpfs.dtsi b/arch/riscv/boot/dts/microchip/mpfs.dtsi
index 5c2963e269b83..4f0d5bdee3da6 100644
--- a/arch/riscv/boot/dts/microchip/mpfs.dtsi
+++ b/arch/riscv/boot/dts/microchip/mpfs.dtsi
@@ -254,7 +254,17 @@ pdma: dma-controller@3000000 {
 		mss_top_sysreg: syscon@20002000 {
 			compatible = "microchip,mpfs-mss-top-sysreg", "syscon", "simple-mfd";
 			reg = <0x0 0x20002000 0x0 0x1000>;
+			#address-cells = <1>;
+			#size-cells = <1>;
 			#reset-cells = <1>;
+
+			irqmux: interrupt-controller@54 {
+				compatible = "microchip,mpfs-irqmux";
+				reg = <0x54 0x4>;
+				#address-cells = <0>;
+				#interrupt-cells = <1>;
+				interrupt-map-mask = <0x7f>;
+			};
 		};
 
 		sysreg_scb: syscon@20003000 {
@@ -471,36 +481,57 @@ mac1: ethernet@20112000 {
 		gpio0: gpio@20120000 {
 			compatible = "microchip,mpfs-gpio";
 			reg = <0x0 0x20120000 0x0 0x1000>;
-			interrupt-parent = <&plic>;
+			interrupt-parent = <&irqmux>;
 			interrupt-controller;
 			#interrupt-cells = <1>;
+			interrupts = <0>, <1>, <2>, <3>,
+				     <4>, <5>, <6>, <7>,
+				     <8>, <9>, <10>, <11>,
+				     <12>, <13>;
 			clocks = <&clkcfg CLK_GPIO0>;
 			gpio-controller;
 			#gpio-cells = <2>;
+			ngpios = <14>;
 			status = "disabled";
 		};
 
 		gpio1: gpio@20121000 {
 			compatible = "microchip,mpfs-gpio";
 			reg = <0x0 0x20121000 0x0 0x1000>;
-			interrupt-parent = <&plic>;
+			interrupt-parent = <&irqmux>;
 			interrupt-controller;
 			#interrupt-cells = <1>;
+			interrupts = <32>, <33>, <34>, <35>,
+				     <36>, <37>, <38>, <39>,
+				     <40>, <41>, <42>, <43>,
+				     <44>, <45>, <46>, <47>,
+				     <48>, <49>, <50>, <51>,
+				     <52>, <53>, <54>, <55>;
 			clocks = <&clkcfg CLK_GPIO1>;
 			gpio-controller;
 			#gpio-cells = <2>;
+			ngpios = <24>;
 			status = "disabled";
 		};
 
 		gpio2: gpio@20122000 {
 			compatible = "microchip,mpfs-gpio";
 			reg = <0x0 0x20122000 0x0 0x1000>;
-			interrupt-parent = <&plic>;
+			interrupt-parent = <&irqmux>;
 			interrupt-controller;
 			#interrupt-cells = <1>;
+			interrupts = <64>, <65>, <66>, <67>,
+				     <68>, <69>, <70>, <71>,
+				     <72>, <73>, <74>, <75>,
+				     <76>, <77>, <78>, <79>,
+				     <80>, <81>, <82>, <83>,
+				     <84>, <85>, <86>, <87>,
+				     <88>, <89>, <90>, <91>,
+				     <92>, <93>, <94>, <95>;
 			clocks = <&clkcfg CLK_GPIO2>;
 			gpio-controller;
 			#gpio-cells = <2>;
+			ngpios = <32>;
 			status = "disabled";
 		};
 
-- 
2.51.0

Re: [RFC v11 1/4] gpio: mpfs: Add interrupt support

[Herve Codina]

Hi Conor,

On Fri, 27 Feb 2026 14:52:27 +0000
Conor Dooley <conor@kernel.org> wrote:

> From: Conor Dooley <conor.dooley@microchip.com>
> 
> Add support for interrupts to the PolarFire SoC GPIO driver. Each GPIO
> has an independent interrupt that is wired to an interrupt mux that sits
> between the controllers and the PLIC. The SoC has more GPIO lines than
> connections from the mux to the PLIC, so some GPIOs must share PLIC
> interrupts. The configuration is not static and is set at runtime,
> conventionally by the platform's firmware. CoreGPIO, the version
> intended for use in the FPGA fabric has two interrupt output ports, one
> is IO_NUM bits wide, as is used in the hardened cores, and the other is
> a single bit with all lines ORed together.
> 
> Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
> ---
> Doing the chained thing kinda covers all the bases at the expense of the
> "direct" mode interrupts that have a dedicated connection to the PLIC.


Seems ok on my side.

Just a nitpick in probe().

Reviewed-by: Herve Codina <herve.codina@bootlin.com>

...
>  static int mpfs_gpio_probe(struct platform_device *pdev)
>  {
>  	struct device *dev = &pdev->dev;
> +	struct device_node *node = pdev->dev.of_node;

dev->of_node instead of pdev->dev.of_node.

or move 'struct device_node *node = pdev->dev.of_node;' at first position
(reverse Xmas tree).

>  	struct mpfs_gpio_chip *mpfs_gpio;
> +	struct gpio_irq_chip *girq;

Best regards,
Hervé

Re: [RFC v11 2/4] dt-bindings: soc: microchip: document PolarFire SoC's gpio interrupt mux

[Herve Codina]

Hi Conor,

On Fri, 27 Feb 2026 14:52:28 +0000
Conor Dooley <conor@kernel.org> wrote:

> From: Conor Dooley <conor.dooley@microchip.com>
> 
> On PolarFire SoC there are more GPIO interrupts than there are interrupt
> lines available on the PLIC, and a runtime configurable mux is used to
> decide which interrupts are assigned direct connections to the PLIC &
> which are relegated to sharing a line.
> 
> Signed-off-by: Conor Dooley <conor.dooley@microchip.com>

Reviewed-by: Herve Codina <herve.codina@bootlin.com>

Best regards,
Hervé

Re: [RFC v11 1/4] gpio: mpfs: Add interrupt support

[Linus Walleij]

Hi Conor,

overall this looks okay, but one detail here:

On Fri, Feb 27, 2026 at 3:53 PM Conor Dooley <conor@kernel.org> wrote:

> From: Conor Dooley <conor.dooley@microchip.com>
>
> Add support for interrupts to the PolarFire SoC GPIO driver. Each GPIO
> has an independent interrupt that is wired to an interrupt mux that sits
> between the controllers and the PLIC. The SoC has more GPIO lines than
> connections from the mux to the PLIC, so some GPIOs must share PLIC
> interrupts. The configuration is not static and is set at runtime,
> conventionally by the platform's firmware. CoreGPIO, the version
> intended for use in the FPGA fabric has two interrupt output ports, one
> is IO_NUM bits wide, as is used in the hardened cores, and the other is
> a single bit with all lines ORed together.
>
> Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
> ---
> Doing the chained thing kinda covers all the bases at the expense of the
> "direct" mode interrupts that have a dedicated connection to the PLIC.

Chained kinda thing, OK...


> +static irqreturn_t mpfs_gpio_irq_handler(int irq, void *data)

static void mpfs_gpio_irq_handler(struct irq_desc *desc)

> +{
> +       struct mpfs_gpio_chip *mpfs_gpio = data;
> +       unsigned int handled = 0;
> +       unsigned long status;
> +       u32 val;
> +       int i;
> +
struct irq_chip *irqchip = irq_desc_get_chip(desc);

chained_irq_enter(irqchip, desc)

> +       regmap_read(mpfs_gpio->regs, MPFS_IRQ_REG, &val);
> +       status = val;
> +       for_each_set_bit(i, &status, MPFS_MAX_NUM_GPIO) {
> +               regmap_write(mpfs_gpio->regs, MPFS_IRQ_REG, BIT(i));
> +               generic_handle_domain_irq(mpfs_gpio->gc.irq.domain, i);
> +               handled++;
> +       }

chained_irq_exit(irqchip, desc)

(no return value)

>  static int mpfs_gpio_probe(struct platform_device *pdev)
>  {
>         struct device *dev = &pdev->dev;
> +       struct device_node *node = pdev->dev.of_node;
>         struct mpfs_gpio_chip *mpfs_gpio;
> +       struct gpio_irq_chip *girq;
>         struct clk *clk;
>         void __iomem *base;
> -       int ngpios;
> +       int ngpios, nirqs, ret;
>
>         mpfs_gpio = devm_kzalloc(dev, sizeof(*mpfs_gpio), GFP_KERNEL);
>         if (!mpfs_gpio)
> @@ -157,6 +243,39 @@ static int mpfs_gpio_probe(struct platform_device *pdev)
>         mpfs_gpio->gc.parent = dev;
>         mpfs_gpio->gc.owner = THIS_MODULE;
>
> +       nirqs = of_irq_count(node);
> +       if (nirqs > MPFS_MAX_NUM_GPIO)
> +               return -ENXIO;
> +
> +       girq = &mpfs_gpio->gc.irq;
> +       girq->num_parents = nirqs;
> +
> +       if (girq->num_parents) {
> +               gpio_irq_chip_set_chip(girq, &mpfs_gpio_irqchip);
> +
> +               girq->parents = devm_kcalloc(&pdev->dev, girq->num_parents,
> +                                            sizeof(*girq->parents), GFP_KERNEL);
> +               if (!girq->parents)
> +                       return -ENOMEM;
> +
> +               for (int i = 0; i < girq->num_parents; i++) {
> +                       ret = platform_get_irq(pdev, i);
> +                       if (ret < 0)
> +                               return ret;
> +
> +                       girq->parents[i] = ret;
> +                       ret = devm_request_irq(dev, girq->parents[i], mpfs_gpio_irq_handler,
> +                                              IRQF_SHARED, NULL, mpfs_gpio);
> +                       if (ret)
> +                               return dev_err_probe(dev, ret,
> +                                                    "failed to request irq for line %u\n",
> +                                                    i);
> +               }

Why do this instead of letting the core do the multi-parent chaining without
explicitly requesting the IRQs like e.g. gpio-dwapb.c does for the
multi-parent case?

Yours,
Linus Walleij

Re: [RFC v11 0/4] PolarFire SoC GPIO interrupt support

[Linus Walleij]

Hi Conor,

On Fri, Feb 27, 2026 at 3:53 PM Conor Dooley <conor@kernel.org> wrote:

> From: Conor Dooley <conor.dooley@microchip.com>
>
> In 2024 I sent a v7 of adding support for the GPIOs on PolarFire SoC,
> which relied on an irqchip driver for a mux sitting between the GPIO
> controllers and the main interrupt controller on the chip:
> https://lore.kernel.org/all/20240723-flatworm-cornflake-8023212f6584@wendy/
>
> Some feedback I got from Thomas there ended up being a complete black
> hole for time spent, and I never managed to make the change he wanted,
> as a house of cards collapsed whenever I tried it. I eventually
> abandoned my attempt to upstream the GPIO driver with interrupt support
> and cut it out of the driver to make progress. I've been carrying what
> Thomas deemed incorrect downstream since.
>
> Recently Hervé upstreamed a patchset for a Renesas chip that deals with
> a mux sitting between a GPIO controller and the platform interrupt
> controller by way of interrupt-map. I saw the opportunity to copy what
> he did, so have gone from an irqchip driver that read the mux setting
> that firmware had configured, to trivial driver that reads the mux
> configuration from devicetree and sets the hardware up to match.
>
> This gets rid entirely of the irqchip driver, so resolves Thomas'
> complaint, but I don't love how the GPIO side of things turned out quite
> as much. The hardware has 41 interrupts but 70 GPIO lines. 38 of these
> are 1:1, direct connections to a dedicated line on the interrupt
> controller and 3 are shared.
> With the parent mux driver, the GPIO driver's interrupt handler was only
> called either for specific direct interrupt or for only the subset that
> are fed into the shared interrupt for that controller. Without the
> parent irqchip from mux driver, and using interrupt-map, I lost the
> ability to use mux driver to selectively call the handler, so now the
> GPIO controller attempts to handle interrupts on all lines.
> Probably this is ultimately not a big deal, it just feels bad to do.
>
> Going RFC here, since it's an entirely different approach. The version
> number is a continuation from before, since the patchset linked above
> got merged at v10 when I stripped the interrupt support.
>
> The mux driver has moved from irqchip to soc, since that's where Hervé's
> ended up.

This surely looks acceptable, I had an inquiry about using proper
chaining for the IRQs but other than that it looks fine to me.

Yours,
Linus Walleij

Re: [RFC v11 3/4] soc: microchip: add mpfs gpio interrupt mux driver

[Herve Codina]

Hi Conor,

On Fri, 27 Feb 2026 14:52:29 +0000
Conor Dooley <conor@kernel.org> wrote:

> From: Conor Dooley <conor.dooley@microchip.com>
> 
> On PolarFire SoC there are more GPIO interrupts than there are interrupt
> lines available on the PLIC, and a runtime configurable mux is used to
> decide which interrupts are assigned direct connections to the PLIC &
> which are relegated to sharing a line.
> 
> Add a driver so that Linux can set the mux based on the interrupt
> mapping in the devicetree.
> 
> Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
> ---
...

> --- a/drivers/soc/microchip/Kconfig
> +++ b/drivers/soc/microchip/Kconfig
> @@ -1,3 +1,14 @@
> +config POLARFIRE_SOC_IRQ_MUX
> +	bool "Microchip PolarFire SoC's GPIO IRQ Mux"
> +	depends on ARCH_MICROCHIP
> +	select REGMAP
> +	select REGMAP_MMIO
> +	default y
> +	help
> +	  Support for the interrupt mux on Polarfire SoC. It sits between
> +	  the GPIO controllers and the PLIC, as only 35 interrupts are shared
> +	  between 3 GPIO controllers with 32 interrupts each.

35 interrupts ?

Previously (other patches) you mentionned 41 (38 + 3).

Also 32 interrutps on each (3 * 32 = 96) but you talked about 70 on previous
patches.

Can you double check or clarify those numbers ?

...
> +++ b/drivers/soc/microchip/mpfs-irqmux.c
> @@ -0,0 +1,167 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Largely copied from rzn1_irqmux.c
> + */
> +
> +#include <linux/bitmap.h>
> +#include <linux/bitops.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_irq.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +
> +#define MPFS_IRQMUX_CR		0x54
> +#define MPFS_IRQMUX_NUM_OUTPUTS	70

Is 70 really the outputs ?

According to previous patches, I would say 41 (38+3).

...
> +static int mpfs_irqmux_probe(struct platform_device *pdev)
> +{
> +	DECLARE_BITMAP(line_done, MPFS_IRQMUX_NUM_OUTPUTS) = {};
> +	struct device *dev = &pdev->dev;
> +	struct device_node *np = dev->of_node;
> +	struct of_imap_parser imap_parser;
> +	struct of_imap_item imap_item;
> +	struct regmap *regmap;
> +	int ret, direct_mode, line, controller, gpio;

Reverse Xmas tree.

> +	u32 tmp, val = 0, old;

...
> +	for_each_of_imap_item(&imap_parser, &imap_item) {
> +
> +		direct_mode = mpfs_irqmux_is_direct_mode(dev, &imap_item.parent_args);
> +		if (direct_mode < 0) {
> +			of_node_put(imap_item.parent_args.np);
> +			return direct_mode;
> +		}
> +
> +		line = imap_item.child_imap[0];
> +		gpio = line % 32;
> +		controller = line / 32;
> +
> +		if (controller > 2) {
> +			of_node_put(imap_item.parent_args.np);
> +			dev_err(dev, "child interrupt number too large: %d\n", line);
> +			return -EINVAL;
> +		}
> +
> +		if (test_and_set_bit(line, line_done)) {

Your bitmap size is MPFS_IRQMUX_NUM_OUTPUTS but you your line variable can
have values from 0 to 95.

Maybe some checks on imap_item.child_imap[0] or line could be added in
order to be be sure that line value will fit in the bitmap.


> +			of_node_put(imap_item.parent_args.np);
> +			dev_err(dev, "Mux output line %d already defined in interrupt-map\n",
> +				line);

line is computed from imap_item.child_imap[0]. It is the input and not the
output.

In rzn1-irqmux.c, the bitmap is used to avoid multiple input lines using the same
output line. Bitmap bits represent outputs.

> +			return -EINVAL;
> +		}
> +
> +		/*
> +		 * There are 41 interrupts assigned to GPIOs, of which 38 are "direct". Since the
> +		 * mux has 32 bits only, 6 of these exclusive/"direct" interrupts remain. These
> +		 * are used by GPIO controller 1's lines 18 to 23. Nothing needs to be done
> +		 * for these interrupts.
> +		 */
> +		if (controller == 1 && gpio >= 18)
> +			continue;
> +
> +		/*
> +		 * The mux has a single register, where bits 0 to 13 mux between GPIO controller
> +		 * 1's 14 GPIOs and GPIO controller 2's first 14 GPIOs. The remaining bits mux
> +		 * between the first 18 GPIOs of controller 1 and the last 18 GPIOS of
> +		 * controller 2. If a bit in the mux's control register is set, the
> +		 * corresponding interrupt line for GPIO controller 0 or 1 will be put in
> +		 * "non-direct" mode. If cleared, the "fabric" controller's will.
> +		 *
> +		 * Register layout:
> +		 *    GPIO 1 interrupt line 17 | mux bit 31 | GPIO 2 interrupt line 31
> +		 *    ...                      | ...        | ...
> +		 *    ...                      | ...        | ...
> +		 *    GPIO 1 interrupt line  0 | mux bit 14 | GPIO 2 interrupt line 14
> +		 *    GPIO 0 interrupt line 13 | mux bit 13 | GPIO 2 interrupt line 13
> +		 *    ...                      | ...        | ...
> +		 *    ...                      | ...        | ...
> +		 *    GPIO 0 interrupt line  0 | mux bit  0 | GPIO 2 interrupt line  0
> +		 *
> +		 * As the binding mandates 70 items, one for each GPIO line, there's no need to
> +		 * handle anything for GPIO controller 2, since the bit will be set for the
> +		 * corresponding line in GPIO controller 0 or 1.

Hum, what happen if the interrupts property is set in the GPIO controller 2 and not
GPIO controllers 0 or 1.

Is it legit ?

If so, should lines coming from GPIO controller 2 be took into account ?

Maybe my comment is not relevant due to some misunderstanding in the not
so obvious mapping.

> +		 */
> +		if (controller == 2)
> +			continue;
> +
> +		/*
> +		 * If in direct mode, the bit is cleared, nothing needs to be done as val is zero
> +		 * initialised and that's the direct mode setting for GPIO controller 0 and 1.
> +		 */
> +		if (direct_mode)
> +			continue;
> +
> +		if (controller == 0)
> +			val |= 1U << gpio;
> +		else
> +			val |= 1U << (gpio + 14);
> +	}
> +
> +	regmap_read(regmap, MPFS_IRQMUX_CR, &old);
> +	regmap_write(regmap, MPFS_IRQMUX_CR, val);
> +
> +	if (val != old)
> +		dev_info(dev, "firmware mux setting of 0x%x overwritten to 0x%x\n", old, val);
> +
> +	return 0;
> +}
> +

Best regards,
Hervé

Re: [RFC v11 3/4] soc: microchip: add mpfs gpio interrupt mux driver

[Conor Dooley]

[-- Attachment #1: Type: text/plain, Size: 8475 bytes --]

On Mon, Mar 02, 2026 at 10:58:24AM +0100, Herve Codina wrote:
> Hi Conor,
> 
> On Fri, 27 Feb 2026 14:52:29 +0000
> Conor Dooley <conor@kernel.org> wrote:
> 
> > From: Conor Dooley <conor.dooley@microchip.com>
> > 
> > On PolarFire SoC there are more GPIO interrupts than there are interrupt
> > lines available on the PLIC, and a runtime configurable mux is used to
> > decide which interrupts are assigned direct connections to the PLIC &
> > which are relegated to sharing a line.
> > 
> > Add a driver so that Linux can set the mux based on the interrupt
> > mapping in the devicetree.
> > 
> > Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
> > ---
> ...
> 
> > --- a/drivers/soc/microchip/Kconfig
> > +++ b/drivers/soc/microchip/Kconfig
> > @@ -1,3 +1,14 @@
> > +config POLARFIRE_SOC_IRQ_MUX
> > +	bool "Microchip PolarFire SoC's GPIO IRQ Mux"
> > +	depends on ARCH_MICROCHIP
> > +	select REGMAP
> > +	select REGMAP_MMIO
> > +	default y
> > +	help
> > +	  Support for the interrupt mux on Polarfire SoC. It sits between
> > +	  the GPIO controllers and the PLIC, as only 35 interrupts are shared
> > +	  between 3 GPIO controllers with 32 interrupts each.
> 
> 35 interrupts ?

I copy-pasted this from Kconfig text for the other mux implementation
that's been floating around since 6.10. I should have double checked
it. I think the 35 came from 32 + 3, not realising that there are 6
lines on GPIO controller 1 that are always in "direct" mode. When I
wrote that description I must have thought those 6 were always in
"non-direct" mode.

> Previously (other patches) you mentionned 41 (38 + 3).
> 
> Also 32 interrutps on each (3 * 32 = 96) but you talked about 70 on previous
> patches.
> 
> Can you double check or clarify those numbers ?

Yeah, this whole description is not good, 70 and 38 + 3 are correct.
The controllers have 14, 24 and 32 lines.

> ...
> > +++ b/drivers/soc/microchip/mpfs-irqmux.c
> > @@ -0,0 +1,167 @@
> > +// SPDX-License-Identifier: GPL-2.0-only
> > +/*
> > + * Largely copied from rzn1_irqmux.c
> > + */
> > +
> > +#include <linux/bitmap.h>
> > +#include <linux/bitops.h>
> > +#include <linux/mfd/syscon.h>
> > +#include <linux/module.h>
> > +#include <linux/of.h>
> > +#include <linux/of_irq.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/regmap.h>
> > +
> > +#define MPFS_IRQMUX_CR		0x54
> > +#define MPFS_IRQMUX_NUM_OUTPUTS	70
> 
> Is 70 really the outputs ?
> 
> According to previous patches, I would say 41 (38+3).

I guess in my head the direction was PLIC -> MUX -> GPIO, cos that's the
way the software follows the chain, so the mux would have 41 inputs and
70 outputs.

> ...
> > +static int mpfs_irqmux_probe(struct platform_device *pdev)
> > +{
> > +	DECLARE_BITMAP(line_done, MPFS_IRQMUX_NUM_OUTPUTS) = {};
> > +	struct device *dev = &pdev->dev;
> > +	struct device_node *np = dev->of_node;
> > +	struct of_imap_parser imap_parser;
> > +	struct of_imap_item imap_item;
> > +	struct regmap *regmap;
> > +	int ret, direct_mode, line, controller, gpio;
> 
> Reverse Xmas tree.
> 
> > +	u32 tmp, val = 0, old;
> 
> ...
> > +	for_each_of_imap_item(&imap_parser, &imap_item) {
> > +
> > +		direct_mode = mpfs_irqmux_is_direct_mode(dev, &imap_item.parent_args);
> > +		if (direct_mode < 0) {
> > +			of_node_put(imap_item.parent_args.np);
> > +			return direct_mode;
> > +		}
> > +
> > +		line = imap_item.child_imap[0];
> > +		gpio = line % 32;
> > +		controller = line / 32;
> > +
> > +		if (controller > 2) {
> > +			of_node_put(imap_item.parent_args.np);
> > +			dev_err(dev, "child interrupt number too large: %d\n", line);
> > +			return -EINVAL;
> > +		}
> > +
> > +		if (test_and_set_bit(line, line_done)) {
> 
> Your bitmap size is MPFS_IRQMUX_NUM_OUTPUTS but you your line variable can
> have values from 0 to 95.

I think this is one of the things that kinda made sense when I started
copying your work, but by the time I was done I had diverged enough that
it didn't really make sense any more. Probably I should keep the check,
but increase the bitmap to 96, not as if packing is going to make a
worthwhile saving.

> Maybe some checks on imap_item.child_imap[0] or line could be added in
> order to be be sure that line value will fit in the bitmap.
> 
> 
> > +			of_node_put(imap_item.parent_args.np);
> > +			dev_err(dev, "Mux output line %d already defined in interrupt-map\n",
> > +				line);
> 
> line is computed from imap_item.child_imap[0]. It is the input and not the
> output.

That's the starting point being the PLIC versus the GPIO controller. I
should probably swap that stuff around I guess?

> 
> In rzn1-irqmux.c, the bitmap is used to avoid multiple input lines using the same
> output line. Bitmap bits represent outputs.

I considered checking the other side too, but excluding the 3 shared
interrupts. Do you think that is worthwhile here? Reuse of what you call
"output lines" is obviously something that I allow, I wanted to make
sure that, as I mandated 70 entries in the property, that they were all
unique.

> > +			return -EINVAL;
> > +		}
> > +
> > +		/*
> > +		 * There are 41 interrupts assigned to GPIOs, of which 38 are "direct". Since the
> > +		 * mux has 32 bits only, 6 of these exclusive/"direct" interrupts remain. These
> > +		 * are used by GPIO controller 1's lines 18 to 23. Nothing needs to be done
> > +		 * for these interrupts.
> > +		 */
> > +		if (controller == 1 && gpio >= 18)
> > +			continue;
> > +
> > +		/*
> > +		 * The mux has a single register, where bits 0 to 13 mux between GPIO controller
> > +		 * 1's 14 GPIOs and GPIO controller 2's first 14 GPIOs. The remaining bits mux
> > +		 * between the first 18 GPIOs of controller 1 and the last 18 GPIOS of
> > +		 * controller 2. If a bit in the mux's control register is set, the
> > +		 * corresponding interrupt line for GPIO controller 0 or 1 will be put in
> > +		 * "non-direct" mode. If cleared, the "fabric" controller's will.
> > +		 *
> > +		 * Register layout:
> > +		 *    GPIO 1 interrupt line 17 | mux bit 31 | GPIO 2 interrupt line 31
> > +		 *    ...                      | ...        | ...
> > +		 *    ...                      | ...        | ...
> > +		 *    GPIO 1 interrupt line  0 | mux bit 14 | GPIO 2 interrupt line 14
> > +		 *    GPIO 0 interrupt line 13 | mux bit 13 | GPIO 2 interrupt line 13
> > +		 *    ...                      | ...        | ...
> > +		 *    ...                      | ...        | ...
> > +		 *    GPIO 0 interrupt line  0 | mux bit  0 | GPIO 2 interrupt line  0
> > +		 *
> > +		 * As the binding mandates 70 items, one for each GPIO line, there's no need to
> > +		 * handle anything for GPIO controller 2, since the bit will be set for the
> > +		 * corresponding line in GPIO controller 0 or 1.
> 
> Hum, what happen if the interrupts property is set in the GPIO controller 2 and not
> GPIO controllers 0 or 1.
> 
> Is it legit ?
> 
> If so, should lines coming from GPIO controller 2 be took into account ?
> 
> Maybe my comment is not relevant due to some misunderstanding in the not
> so obvious mapping.

My logic here was that what is done in the controller nodes doesn't
matter, because I will always mandate that if the map property is
provided in the mux node that it has 70 items. Even if controller 0 and
1 are not used, this driver will still be able to read the mappings for
them and set the mux correctly. Whether or not there's an interrupts
property in any of the controllers shouldn't matter here at all, when it
comes to writing the mux, right?

Thanks for taking a look at the series :+1:

Cheers,
Conor.

> 
> > +		 */
> > +		if (controller == 2)
> > +			continue;
> > +
> > +		/*
> > +		 * If in direct mode, the bit is cleared, nothing needs to be done as val is zero
> > +		 * initialised and that's the direct mode setting for GPIO controller 0 and 1.
> > +		 */
> > +		if (direct_mode)
> > +			continue;
> > +
> > +		if (controller == 0)
> > +			val |= 1U << gpio;
> > +		else
> > +			val |= 1U << (gpio + 14);
> > +	}
> > +
> > +	regmap_read(regmap, MPFS_IRQMUX_CR, &old);
> > +	regmap_write(regmap, MPFS_IRQMUX_CR, val);
> > +
> > +	if (val != old)
> > +		dev_info(dev, "firmware mux setting of 0x%x overwritten to 0x%x\n", old, val);
> > +
> > +	return 0;
> > +}
> > +


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