pinctrl: add pinctrl/GPIO driver for Apple SoCs

This driver adds support for the pinctrl / GPIO hardware found
on some Apple SoCs.
Co-developed-by: Stan Skowronek <stan@corellium.com>
Signed-off-by: Stan Skowronek <stan@corellium.com>
Signed-off-by: Joey Gouly <joey.gouly@arm.com>
Acked-by: Hector Martin <marcan@marcan.st>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211026175815.52703-5-joey.gouly@arm.comSigned-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/pinctrl/Kconfig

@@ -31,6 +31,22 @@ config DEBUG_PINCTRL
 	help
 	  Say Y here to add some extra checks and diagnostics to PINCTRL calls.
 
+config PINCTRL_APPLE_GPIO
+	tristate "Apple SoC GPIO pin controller driver"
+	depends on ARCH_APPLE
+	select PINMUX
+	select GPIOLIB
+	select GPIOLIB_IRQCHIP
+	select GENERIC_PINCTRL_GROUPS
+	select GENERIC_PINMUX_FUNCTIONS
+	select OF_GPIO
+	help
+	  This is the driver for the GPIO controller found on Apple ARM SoCs,
+	  including M1.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called pinctrl-apple-gpio.
+
 config PINCTRL_ARTPEC6
 	bool "Axis ARTPEC-6 pin controller driver"
 	depends on MACH_ARTPEC6

drivers/pinctrl/Makefile

@@ -8,6 +8,7 @@ obj-$(CONFIG_PINMUX)		+= pinmux.o
 obj-$(CONFIG_PINCONF)		+= pinconf.o
 obj-$(CONFIG_OF)		+= devicetree.o
 obj-$(CONFIG_GENERIC_PINCONF)	+= pinconf-generic.o
+obj-$(CONFIG_PINCTRL_APPLE_GPIO) += pinctrl-apple-gpio.o
 obj-$(CONFIG_PINCTRL_ARTPEC6)	+= pinctrl-artpec6.o
 obj-$(CONFIG_PINCTRL_AS3722)	+= pinctrl-as3722.o
 obj-$(CONFIG_PINCTRL_AXP209)	+= pinctrl-axp209.o

drivers/pinctrl/pinctrl-apple-gpio.c

+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Apple SoC pinctrl+GPIO+external IRQ driver
+ *
+ * Copyright (C) The Asahi Linux Contributors
+ * Copyright (C) 2020 Corellium LLC
+ *
+ * Based on: pinctrl-pistachio.c
+ * Copyright (C) 2014 Imagination Technologies Ltd.
+ * Copyright (C) 2014 Google, Inc.
+ */
+
+#include <dt-bindings/pinctrl/apple.h>
+#include <linux/gpio/driver.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
+#include <linux/pinctrl/pinctrl.h>
+#include <linux/pinctrl/pinmux.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+#include "pinctrl-utils.h"
+#include "core.h"
+#include "pinmux.h"
+
+struct apple_gpio_pinctrl {
+	struct device *dev;
+	struct pinctrl_dev *pctldev;
+
+	void __iomem *base;
+	struct regmap *map;
+
+	struct pinctrl_desc pinctrl_desc;
+	struct gpio_chip gpio_chip;
+	struct irq_chip irq_chip;
+	u8 irqgrps[0];
+};
+
+#define REG_GPIO(x)          (4 * (x))
+#define REG_GPIOx_DATA       BIT(0)
+#define REG_GPIOx_MODE       GENMASK(3, 1)
+#define REG_GPIOx_OUT        1
+#define REG_GPIOx_IN_IRQ_HI  2
+#define REG_GPIOx_IN_IRQ_LO  3
+#define REG_GPIOx_IN_IRQ_UP  4
+#define REG_GPIOx_IN_IRQ_DN  5
+#define REG_GPIOx_IN_IRQ_ANY 6
+#define REG_GPIOx_IN_IRQ_OFF 7
+#define REG_GPIOx_PERIPH     GENMASK(6, 5)
+#define REG_GPIOx_PULL       GENMASK(8, 7)
+#define REG_GPIOx_PULL_OFF   0
+#define REG_GPIOx_PULL_DOWN  1
+#define REG_GPIOx_PULL_UP_STRONG 2
+#define REG_GPIOx_PULL_UP    3
+#define REG_GPIOx_INPUT_ENABLE BIT(9)
+#define REG_GPIOx_DRIVE_STRENGTH0 GENMASK(11, 10)
+#define REG_GPIOx_SCHMITT    BIT(15)
+#define REG_GPIOx_GRP        GENMASK(18, 16)
+#define REG_GPIOx_LOCK       BIT(21)
+#define REG_GPIOx_DRIVE_STRENGTH1 GENMASK(23, 22)
+#define REG_IRQ(g, x)        (0x800 + 0x40 * (g) + 4 * ((x) >> 5))
+
+struct regmap_config regmap_config = {
+	.reg_bits = 32,
+	.val_bits = 32,
+	.reg_stride = 4,
+	.cache_type = REGCACHE_FLAT,
+	.max_register = 512 * sizeof(u32),
+	.num_reg_defaults_raw = 512,
+	.use_relaxed_mmio = true
+};
+
+// No locking needed to mask/unmask IRQs as the interrupt mode is per pin-register.
+static void apple_gpio_set_reg(struct apple_gpio_pinctrl *pctl,
+			       unsigned int pin, u32 mask, u32 value)
+{
+	regmap_update_bits(pctl->map, REG_GPIO(pin), mask, value);
+}
+
+static uint32_t apple_gpio_get_reg(struct apple_gpio_pinctrl *pctl,
+				   unsigned int pin)
+{
+	unsigned int val = 0;
+
+	regmap_read(pctl->map, REG_GPIO(pin), &val);
+	return val;
+}
+
+/* Pin controller functions */
+
+static int apple_gpio_dt_node_to_map(struct pinctrl_dev *pctldev,
+				     struct device_node *node,
+				     struct pinctrl_map **map,
+				     unsigned *num_maps)
+{
+	unsigned reserved_maps;
+	struct apple_gpio_pinctrl *pctl;
+	u32 pinfunc, pin, func;
+	int num_pins, i, ret;
+	const char *group_name;
+	const char *function_name;
+
+	*map = NULL;
+	*num_maps = 0;
+	reserved_maps = 0;
+
+	pctl = pinctrl_dev_get_drvdata(pctldev);
+
+	ret = of_property_count_u32_elems(node, "pinmux");
+	if (ret <= 0) {
+		dev_err(pctl->dev,
+			"missing or empty pinmux property in node %pOFn.\n",
+			node);
+		return ret;
+	}
+
+	num_pins = ret;
+
+	ret = pinctrl_utils_reserve_map(pctldev, map, &reserved_maps, num_maps,
+					num_pins);
+	if (ret)
+		return ret;
+
+	for (i = 0; i < num_pins; i++) {
+		ret = of_property_read_u32_index(node, "pinmux", i, &pinfunc);
+		if (ret)
+			goto free_map;
+
+		pin = APPLE_PIN(pinfunc);
+		func = APPLE_FUNC(pinfunc);
+
+		if (func >= pinmux_generic_get_function_count(pctldev)) {
+			ret = -EINVAL;
+			goto free_map;
+		}
+
+		group_name = pinctrl_generic_get_group_name(pctldev, pin);
+		function_name =
+			pinmux_generic_get_function_name(pctl->pctldev, func);
+		ret = pinctrl_utils_add_map_mux(pctl->pctldev, map,
+						&reserved_maps, num_maps,
+						group_name, function_name);
+		if (ret)
+			goto free_map;
+	}
+
+free_map:
+	if (ret < 0)
+		pinctrl_utils_free_map(pctldev, *map, *num_maps);
+
+	return ret;
+}
+
+static const struct pinctrl_ops apple_gpio_pinctrl_ops = {
+	.get_groups_count = pinctrl_generic_get_group_count,
+	.get_group_name = pinctrl_generic_get_group_name,
+	.get_group_pins = pinctrl_generic_get_group_pins,
+	.dt_node_to_map = apple_gpio_dt_node_to_map,
+	.dt_free_map = pinctrl_utils_free_map,
+};
+
+/* Pin multiplexer functions */
+
+static int apple_gpio_pinmux_set(struct pinctrl_dev *pctldev, unsigned func,
+				    unsigned group)
+{
+	struct apple_gpio_pinctrl *pctl = pinctrl_dev_get_drvdata(pctldev);
+
+	apple_gpio_set_reg(
+		pctl, group, REG_GPIOx_PERIPH | REG_GPIOx_INPUT_ENABLE,
+		FIELD_PREP(REG_GPIOx_PERIPH, func) | REG_GPIOx_INPUT_ENABLE);
+
+	return 0;
+}
+
+static const struct pinmux_ops apple_gpio_pinmux_ops = {
+	.get_functions_count = pinmux_generic_get_function_count,
+	.get_function_name = pinmux_generic_get_function_name,
+	.get_function_groups = pinmux_generic_get_function_groups,
+	.set_mux = apple_gpio_pinmux_set,
+	.strict = true,
+};
+
+/* GPIO chip functions */
+
+static int apple_gpio_get_direction(struct gpio_chip *chip,
+					 unsigned int offset)
+{
+	struct apple_gpio_pinctrl *pctl = gpiochip_get_data(chip);
+	unsigned int reg = apple_gpio_get_reg(pctl, offset);
+
+	return (FIELD_GET(REG_GPIOx_MODE, reg) == REG_GPIOx_OUT) ?
+		       GPIO_LINE_DIRECTION_OUT : GPIO_LINE_DIRECTION_IN;
+}
+
+static int apple_gpio_get(struct gpio_chip *chip, unsigned offset)
+{
+	struct apple_gpio_pinctrl *pctl = gpiochip_get_data(chip);
+	unsigned int reg = apple_gpio_get_reg(pctl, offset);
+
+	/*
+	 * If this is an input GPIO, read the actual value (not the
+	 * cached regmap value)
+	 */
+	if (FIELD_GET(REG_GPIOx_MODE, reg) != REG_GPIOx_OUT)
+		reg = readl_relaxed(pctl->base + REG_GPIO(offset));
+
+	return !!(reg & REG_GPIOx_DATA);
+}
+
+static void apple_gpio_set(struct gpio_chip *chip, unsigned int offset,
+				int value)
+{
+	struct apple_gpio_pinctrl *pctl = gpiochip_get_data(chip);
+
+	apple_gpio_set_reg(pctl, offset, REG_GPIOx_DATA,
+			   value ? REG_GPIOx_DATA : 0);
+}
+
+static int apple_gpio_direction_input(struct gpio_chip *chip,
+					   unsigned int offset)
+{
+	struct apple_gpio_pinctrl *pctl = gpiochip_get_data(chip);
+
+	apple_gpio_set_reg(pctl, offset,
+			   REG_GPIOx_PERIPH | REG_GPIOx_MODE | REG_GPIOx_DATA |
+				   REG_GPIOx_INPUT_ENABLE,
+			   FIELD_PREP(REG_GPIOx_MODE, REG_GPIOx_IN_IRQ_OFF) |
+				   REG_GPIOx_INPUT_ENABLE);
+	return 0;
+}
+
+static int apple_gpio_direction_output(struct gpio_chip *chip,
+					    unsigned int offset, int value)
+{
+	struct apple_gpio_pinctrl *pctl = gpiochip_get_data(chip);
+
+	apple_gpio_set_reg(pctl, offset,
+			   REG_GPIOx_PERIPH | REG_GPIOx_MODE | REG_GPIOx_DATA,
+			   FIELD_PREP(REG_GPIOx_MODE, REG_GPIOx_OUT) |
+				   (value ? REG_GPIOx_DATA : 0));
+	return 0;
+}
+
+/* IRQ chip functions */
+
+static void apple_gpio_irq_ack(struct irq_data *data)
+{
+	struct apple_gpio_pinctrl *pctl =
+		gpiochip_get_data(irq_data_get_irq_chip_data(data));
+	unsigned int irqgrp =
+		FIELD_GET(REG_GPIOx_GRP, apple_gpio_get_reg(pctl, data->hwirq));
+
+	writel(BIT(data->hwirq & 31),
+	       pctl->base + REG_IRQ(irqgrp, data->hwirq));
+}
+
+static int apple_gpio_irq_type(unsigned int type)
+{
+	switch (type & IRQ_TYPE_SENSE_MASK) {
+	case IRQ_TYPE_EDGE_RISING:
+		return REG_GPIOx_IN_IRQ_UP;
+	case IRQ_TYPE_EDGE_FALLING:
+		return REG_GPIOx_IN_IRQ_DN;
+	case IRQ_TYPE_EDGE_BOTH:
+		return REG_GPIOx_IN_IRQ_ANY;
+	case IRQ_TYPE_LEVEL_HIGH:
+		return REG_GPIOx_IN_IRQ_HI;
+	case IRQ_TYPE_LEVEL_LOW:
+		return REG_GPIOx_IN_IRQ_LO;
+	default:
+		return -EINVAL;
+	}
+}
+
+static void apple_gpio_irq_mask(struct irq_data *data)
+{
+	struct apple_gpio_pinctrl *pctl =
+		gpiochip_get_data(irq_data_get_irq_chip_data(data));
+	apple_gpio_set_reg(pctl, data->hwirq, REG_GPIOx_MODE,
+			   FIELD_PREP(REG_GPIOx_MODE, REG_GPIOx_IN_IRQ_OFF));
+}
+
+static void apple_gpio_irq_unmask(struct irq_data *data)
+{
+	struct apple_gpio_pinctrl *pctl =
+		gpiochip_get_data(irq_data_get_irq_chip_data(data));
+	int irqtype = apple_gpio_irq_type(irqd_get_trigger_type(data));
+
+	apple_gpio_set_reg(pctl, data->hwirq, REG_GPIOx_MODE,
+			   FIELD_PREP(REG_GPIOx_MODE, irqtype));
+}
+
+static unsigned int apple_gpio_irq_startup(struct irq_data *data)
+{
+	struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
+	struct apple_gpio_pinctrl *pctl = gpiochip_get_data(chip);
+
+	apple_gpio_set_reg(pctl, data->hwirq, REG_GPIOx_GRP,
+			   FIELD_PREP(REG_GPIOx_GRP, 0));
+
+	apple_gpio_direction_input(chip, data->hwirq);
+	apple_gpio_irq_unmask(data);
+
+	return 0;
+}
+
+static int apple_gpio_irq_set_type(struct irq_data *data,
+					unsigned int type)
+{
+	struct apple_gpio_pinctrl *pctl =
+		gpiochip_get_data(irq_data_get_irq_chip_data(data));
+	int irqtype = apple_gpio_irq_type(type);
+
+	if (irqtype < 0)
+		return irqtype;
+
+	apple_gpio_set_reg(pctl, data->hwirq, REG_GPIOx_MODE,
+			   FIELD_PREP(REG_GPIOx_MODE, irqtype));
+
+	if (type & IRQ_TYPE_LEVEL_MASK)
+		irq_set_handler_locked(data, handle_level_irq);
+	else
+		irq_set_handler_locked(data, handle_edge_irq);
+	return 0;
+}
+
+static void apple_gpio_irq_handler(struct irq_desc *desc)
+{
+	struct irq_chip *chip = irq_desc_get_chip(desc);
+	u8 *grpp = irq_desc_get_handler_data(desc);
+	struct apple_gpio_pinctrl *pctl;
+	unsigned int pinh, pinl;
+	unsigned long pending;
+	struct gpio_chip *gc;
+
+	pctl = container_of(grpp - *grpp, typeof(*pctl), irqgrps[0]);
+	gc = &pctl->gpio_chip;
+
+	chained_irq_enter(chip, desc);
+	for (pinh = 0; pinh < gc->ngpio; pinh += 32) {
+		pending = readl_relaxed(pctl->base + REG_IRQ(*grpp, pinh));
+		for_each_set_bit(pinl, &pending, 32)
+			generic_handle_domain_irq(gc->irq.domain, pinh + pinl);
+	}
+	chained_irq_exit(chip, desc);
+}
+
+static struct irq_chip apple_gpio_irqchip = {
+	.name		= "Apple-GPIO",
+	.irq_startup	= apple_gpio_irq_startup,
+	.irq_ack	= apple_gpio_irq_ack,
+	.irq_mask	= apple_gpio_irq_mask,
+	.irq_unmask	= apple_gpio_irq_unmask,
+	.irq_set_type	= apple_gpio_irq_set_type,
+};
+
+/* Probe & register */
+
+static int apple_gpio_register(struct apple_gpio_pinctrl *pctl)
+{
+	struct gpio_irq_chip *girq = &pctl->gpio_chip.irq;
+	void **irq_data = NULL;
+	int ret;
+
+	if (!of_property_read_bool(pctl->dev->of_node, "gpio-controller"))
+		return dev_err_probe(pctl->dev,	-ENODEV,
+				     "No gpio-controller property\n");
+
+	pctl->irq_chip = apple_gpio_irqchip;
+
+	pctl->gpio_chip.label = dev_name(pctl->dev);
+	pctl->gpio_chip.request = gpiochip_generic_request;
+	pctl->gpio_chip.free = gpiochip_generic_free;
+	pctl->gpio_chip.get_direction = apple_gpio_get_direction;
+	pctl->gpio_chip.direction_input = apple_gpio_direction_input;
+	pctl->gpio_chip.direction_output = apple_gpio_direction_output;
+	pctl->gpio_chip.get = apple_gpio_get;
+	pctl->gpio_chip.set = apple_gpio_set;
+	pctl->gpio_chip.base = -1;
+	pctl->gpio_chip.ngpio = pctl->pinctrl_desc.npins;
+	pctl->gpio_chip.parent = pctl->dev;
+	pctl->gpio_chip.of_node = pctl->dev->of_node;
+
+	if (girq->num_parents) {
+		int i;
+
+		girq->chip = &pctl->irq_chip;
+		girq->parent_handler = apple_gpio_irq_handler;
+
+		girq->parents = kmalloc_array(girq->num_parents,
+					      sizeof(*girq->parents),
+					      GFP_KERNEL);
+		irq_data = kmalloc_array(girq->num_parents, sizeof(*irq_data),
+					 GFP_KERNEL);
+		if (!girq->parents || !irq_data) {
+			ret = -ENOMEM;
+			goto out;
+		}
+
+		for (i = 0; i < girq->num_parents; i++) {
+			ret = platform_get_irq(to_platform_device(pctl->dev),
+					       i);
+			if (ret < 0)
+				goto out;
+
+			girq->parents[i] = ret;
+			pctl->irqgrps[i] = i;
+			irq_data[i] = &pctl->irqgrps[i];
+		}
+
+		girq->parent_handler_data_array = irq_data;
+		girq->per_parent_data = true;
+		girq->default_type = IRQ_TYPE_NONE;
+		girq->handler = handle_level_irq;
+	}
+
+	ret = devm_gpiochip_add_data(pctl->dev, &pctl->gpio_chip, pctl);
+out:
+	kfree(girq->parents);
+	kfree(irq_data);
+
+	return ret;
+}
+
+static int apple_gpio_pinctrl_probe(struct platform_device *pdev)
+{
+	struct apple_gpio_pinctrl *pctl;
+	struct pinctrl_pin_desc *pins;
+	unsigned int npins;
+	const char **pin_names;
+	unsigned int *pin_nums;
+	static const char* pinmux_functions[] = {
+		"gpio", "periph1", "periph2", "periph3"
+	};
+	unsigned int i, nirqs = 0;
+	int res;
+
+	if (of_property_read_bool(pdev->dev.of_node, "interrupt-controller")) {
+		res = platform_irq_count(pdev);
+		if (res > 0)
+			nirqs = res;
+	}
+
+	pctl = devm_kzalloc(&pdev->dev, struct_size(pctl, irqgrps, nirqs),
+			    GFP_KERNEL);
+	if (!pctl)
+		return -ENOMEM;
+	pctl->dev = &pdev->dev;
+	pctl->gpio_chip.irq.num_parents = nirqs;
+	dev_set_drvdata(&pdev->dev, pctl);
+
+	if (of_property_read_u32(pdev->dev.of_node, "apple,npins", &npins))
+		return dev_err_probe(&pdev->dev, -EINVAL,
+				     "apple,npins property not found\n");
+
+	pins = devm_kmalloc_array(&pdev->dev, npins, sizeof(pins[0]),
+				  GFP_KERNEL);
+	pin_names = devm_kmalloc_array(&pdev->dev, npins, sizeof(pin_names[0]),
+				       GFP_KERNEL);
+	pin_nums = devm_kmalloc_array(&pdev->dev, npins, sizeof(pin_nums[0]),
+				      GFP_KERNEL);
+	if (!pins || !pin_names || !pin_nums)
+		return -ENOMEM;
+
+	pctl->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(pctl->base))
+		return PTR_ERR(pctl->base);
+
+	pctl->map = devm_regmap_init_mmio(&pdev->dev, pctl->base, &regmap_config);
+	if (IS_ERR(pctl->map))
+		return dev_err_probe(&pdev->dev, PTR_ERR(pctl->map),
+				     "Failed to create regmap\n");
+
+	for (i = 0; i < npins; i++) {
+		pins[i].number = i;
+		pins[i].name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "PIN%u", i);
+		pins[i].drv_data = pctl;
+		pin_names[i] = pins[i].name;
+		pin_nums[i] = i;
+	}
+
+	pctl->pinctrl_desc.name = dev_name(pctl->dev);
+	pctl->pinctrl_desc.pins = pins;
+	pctl->pinctrl_desc.npins = npins;
+	pctl->pinctrl_desc.pctlops = &apple_gpio_pinctrl_ops;
+	pctl->pinctrl_desc.pmxops = &apple_gpio_pinmux_ops;
+
+	pctl->pctldev =	devm_pinctrl_register(&pdev->dev, &pctl->pinctrl_desc, pctl);
+	if (IS_ERR(pctl->pctldev))
+		return dev_err_probe(&pdev->dev, PTR_ERR(pctl->pctldev),
+				     "Failed to register pinctrl device.\n");
+
+	for (i = 0; i < npins; i++) {
+		res = pinctrl_generic_add_group(pctl->pctldev, pins[i].name,
+						pin_nums + i, 1, pctl);
+		if (res < 0)
+			return dev_err_probe(pctl->dev, res,
+					     "Failed to register group");
+	}
+
+	for (i = 0; i < ARRAY_SIZE(pinmux_functions); ++i) {
+		res = pinmux_generic_add_function(pctl->pctldev, pinmux_functions[i],
+						  pin_names, npins, pctl);
+		if (res < 0)
+			return dev_err_probe(pctl->dev, res,
+					     "Failed to register function.");
+	}
+
+	return apple_gpio_register(pctl);
+}
+
+static const struct of_device_id apple_gpio_pinctrl_of_match[] = {
+	{ .compatible = "apple,pinctrl", },
+	{ }
+};
+
+static struct platform_driver apple_gpio_pinctrl_driver = {
+	.driver = {
+		.name = "apple-gpio-pinctrl",
+		.of_match_table = apple_gpio_pinctrl_of_match,
+		.suppress_bind_attrs = true,
+	},
+	.probe = apple_gpio_pinctrl_probe,
+};
+module_platform_driver(apple_gpio_pinctrl_driver);
+
+MODULE_DESCRIPTION("Apple pinctrl/GPIO driver");
+MODULE_AUTHOR("Stan Skowronek <stan@corellium.com>");
+MODULE_AUTHOR("Joey Gouly <joey.gouly@arm.com>");
+MODULE_LICENSE("GPL v2");