Date:   Tue, 12 Jul 2022 16:32:35 +0200
From:   Henning Schild <henning.schild@...mens.com>
To:     <linux-kernel@...r.kernel.org>, <linux-gpio@...r.kernel.org>,
        "Bartosz Golaszewski" <brgl@...ev.pl>,
        Linus Walleij <linus.walleij@...aro.org>,
        Tasanakorn Phaipool <tasanakorn@...il.com>
CC:     Sheng-Yuan Huang <syhuang3@...oton.com>,
        Kuan-Wei Ho <cwho@...oton.com>,
        Andy Shevchenko <andy.shevchenko@...il.com>,
        Henning Schild <henning.schild@...mens.com>
Subject: [PATCH v3 1/3] gpio: nct6116d: add new driver for several Nuvoton super io chips

This patch adds gpio support for several Nuvoton NCTXXX chips. These
Super-I/O chips offer multiple functions of which several already have
drivers in the kernel, i.e. hwmon and watchdog.

Signed-off-by: Henning Schild <henning.schild@...mens.com>
---
 drivers/gpio/Kconfig         |   9 +
 drivers/gpio/Makefile        |   1 +
 drivers/gpio/gpio-nct6116d.c | 412 +++++++++++++++++++++++++++++++++++
 3 files changed, 422 insertions(+)
 create mode 100644 drivers/gpio/gpio-nct6116d.c

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index b01961999ced..1f1ec035f3c6 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -899,6 +899,15 @@ config GPIO_IT87
 	  To compile this driver as a module, choose M here: the module will
 	  be called gpio_it87.
 
+config GPIO_NCT6116D
+	tristate "Nuvoton Super-I/O GPIO support"
+	help
+	  This option enables support for GPIOs found on Nuvoton Super-I/O
+	  chips NCT5104D, NCT6106D, NCT6116D, NCT6122D.
+
+	  To compile this driver as a module, choose M here: the module will
+	  be called gpio_nct6116d.
+
 config GPIO_SCH
 	tristate "Intel SCH/TunnelCreek/Centerton/Quark X1000 GPIO"
 	depends on (X86 || COMPILE_TEST) && ACPI
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 14352f6dfe8e..87f1b0a0cda2 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -107,6 +107,7 @@ obj-$(CONFIG_GPIO_MT7621)		+= gpio-mt7621.o
 obj-$(CONFIG_GPIO_MVEBU)		+= gpio-mvebu.o
 obj-$(CONFIG_GPIO_MXC)			+= gpio-mxc.o
 obj-$(CONFIG_GPIO_MXS)			+= gpio-mxs.o
+obj-$(CONFIG_GPIO_NCT6116D)		+= gpio-nct6116d.o
 obj-$(CONFIG_GPIO_OCTEON)		+= gpio-octeon.o
 obj-$(CONFIG_GPIO_OMAP)			+= gpio-omap.o
 obj-$(CONFIG_GPIO_PALMAS)		+= gpio-palmas.o
diff --git a/drivers/gpio/gpio-nct6116d.c b/drivers/gpio/gpio-nct6116d.c
new file mode 100644
index 000000000000..2ff92f3e11aa
--- /dev/null
+++ b/drivers/gpio/gpio-nct6116d.c
@@ -0,0 +1,412 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * GPIO driver for Nuvoton Super-I/O chips NCT5104D, NCT6106D, NCT6116D, NCT6122D
+ *
+ * Authors:
+ *  Tasanakorn Phaipool <tasanakorn@...il.com>
+ *  Sheng-Yuan Huang <syhuang3@...oton.com>
+ *  Kuan-Wei Ho <cwho@...oton.com>
+ *  Henning Schild <henning.schild@...mens.com>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/gpio/driver.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+/*
+ * Super-I/O registers
+ */
+#define SIO_LDSEL		0x07	/* Logical device select */
+#define SIO_CHIPID		0x20	/* Chaip ID (2 bytes) */
+#define SIO_GPIO_ENABLE		0x30	/* GPIO enable */
+
+#define SIO_LD_GPIO		0x07	/* GPIO logical device */
+#define SIO_UNLOCK_KEY		0x87	/* Key to enable Super-I/O */
+#define SIO_LOCK_KEY		0xAA	/* Key to disable Super-I/O */
+
+#define SIO_ID_MASK		GENMASK(15, 4)
+#define SIO_NCT5104D_ID		0x1061
+#define SIO_NCT6106D_ID		0xC452
+#define SIO_NCT6116D_ID		0xD282
+#define SIO_NCT6122D_ID		0xD2A3
+
+enum chips {
+	nct5104d,
+	nct6106d,
+	nct6116d,
+	nct6122d,
+};
+
+static const char * const nct6116d_names[] = {
+	[nct5104d] = "nct5104d",
+	[nct6106d] = "nct6106d",
+	[nct6116d] = "nct6116d",
+	[nct6122d] = "nct6122d",
+};
+
+struct nct6116d_sio {
+	int addr;
+	enum chips type;
+};
+
+struct nct6116d_gpio_bank {
+	struct gpio_chip chip;
+	unsigned int regbase;
+	struct nct6116d_gpio_data *data;
+};
+
+struct nct6116d_gpio_data {
+	struct nct6116d_sio *sio;
+	int nr_bank;
+	struct nct6116d_gpio_bank *bank;
+};
+
+/*
+ * Super-I/O functions.
+ */
+
+static inline int superio_inb(int base, int reg)
+{
+	outb(reg, base);
+	return inb(base + 1);
+}
+
+static int superio_inw(int base, int reg)
+{
+	int val;
+
+	outb(reg++, base);
+	val = inb(base + 1) << 8;
+	outb(reg, base);
+	val |= inb(base + 1);
+
+	return val;
+}
+
+static inline void superio_outb(int base, int reg, int val)
+{
+	outb(reg, base);
+	outb(val, base + 1);
+}
+
+static inline int superio_enter(int base)
+{
+	/* Don't step on other drivers' I/O space by accident. */
+	if (!request_muxed_region(base, 2, KBUILD_MODNAME)) {
+		pr_err("I/O address 0x%04x already in use\n", base);
+		return -EBUSY;
+	}
+
+	/* According to the datasheet the key must be send twice. */
+	outb(SIO_UNLOCK_KEY, base);
+	outb(SIO_UNLOCK_KEY, base);
+
+	return 0;
+}
+
+static inline void superio_select(int base, int ld)
+{
+	outb(SIO_LDSEL, base);
+	outb(ld, base + 1);
+}
+
+static inline void superio_exit(int base)
+{
+	outb(SIO_LOCK_KEY, base);
+	release_region(base, 2);
+}
+
+/*
+ * GPIO chip.
+ */
+
+#define gpio_dir(base) ((base) + 0)
+#define gpio_data(base) ((base) + 1)
+
+static inline void *nct6116d_to_gpio_bank(struct gpio_chip *chip)
+{
+	return container_of(chip, struct nct6116d_gpio_bank, chip);
+}
+
+static int nct6116d_gpio_get_direction(struct gpio_chip *chip, unsigned int offset)
+{
+	struct nct6116d_gpio_bank *bank = nct6116d_to_gpio_bank(chip);
+	struct nct6116d_sio *sio = bank->data->sio;
+	int err;
+	u8 dir;
+
+	err = superio_enter(sio->addr);
+	if (err)
+		return err;
+	superio_select(sio->addr, SIO_LD_GPIO);
+
+	dir = superio_inb(sio->addr, gpio_dir(bank->regbase));
+
+	superio_exit(sio->addr);
+
+	if (dir & 1 << offset)
+		return GPIO_LINE_DIRECTION_OUT;
+
+	return GPIO_LINE_DIRECTION_IN;
+}
+
+static int nct6116d_gpio_direction_in(struct gpio_chip *chip, unsigned int offset)
+{
+	struct nct6116d_gpio_bank *bank = nct6116d_to_gpio_bank(chip);
+	struct nct6116d_sio *sio = bank->data->sio;
+	int err;
+	u8 dir;
+
+	err = superio_enter(sio->addr);
+	if (err)
+		return err;
+	superio_select(sio->addr, SIO_LD_GPIO);
+
+	dir = superio_inb(sio->addr, gpio_dir(bank->regbase));
+	dir |= BIT(offset);
+	superio_outb(sio->addr, gpio_dir(bank->regbase), dir);
+
+	superio_exit(sio->addr);
+
+	return 0;
+}
+
+static int nct6116d_gpio_get(struct gpio_chip *chip, unsigned int offset)
+{
+	struct nct6116d_gpio_bank *bank = nct6116d_to_gpio_bank(chip);
+	struct nct6116d_sio *sio = bank->data->sio;
+	int err;
+	u8 data;
+
+	err = superio_enter(sio->addr);
+	if (err)
+		return err;
+	superio_select(sio->addr, SIO_LD_GPIO);
+
+	data = superio_inb(sio->addr, gpio_data(bank->regbase));
+
+	superio_exit(sio->addr);
+
+	return !!(data & BIT(offset));
+}
+
+static int nct6116d_gpio_direction_out(struct gpio_chip *chip,
+				     unsigned int offset, int value)
+{
+	struct nct6116d_gpio_bank *bank = nct6116d_to_gpio_bank(chip);
+	struct nct6116d_sio *sio = bank->data->sio;
+	u8 dir, data_out;
+	int err;
+
+	err = superio_enter(sio->addr);
+	if (err)
+		return err;
+	superio_select(sio->addr, SIO_LD_GPIO);
+
+	data_out = superio_inb(sio->addr, gpio_data(bank->regbase));
+	if (value)
+		data_out |= BIT(offset);
+	else
+		data_out &= ~BIT(offset);
+	superio_outb(sio->addr, gpio_data(bank->regbase), data_out);
+
+	dir = superio_inb(sio->addr, gpio_dir(bank->regbase));
+	dir &= ~BIT(offset);
+	superio_outb(sio->addr, gpio_dir(bank->regbase), dir);
+
+	superio_exit(sio->addr);
+
+	return 0;
+}
+
+static void nct6116d_gpio_set(struct gpio_chip *chip, unsigned int offset, int value)
+{
+	struct nct6116d_gpio_bank *bank = nct6116d_to_gpio_bank(chip);
+	struct nct6116d_sio *sio = bank->data->sio;
+	u8 data_out;
+	int err;
+
+	err = superio_enter(sio->addr);
+	if (err)
+		return;
+	superio_select(sio->addr, SIO_LD_GPIO);
+
+	data_out = superio_inb(sio->addr, gpio_data(bank->regbase));
+	if (value)
+		data_out |= BIT(offset);
+	else
+		data_out &= ~BIT(offset);
+	superio_outb(sio->addr, gpio_data(bank->regbase), data_out);
+
+	superio_exit(sio->addr);
+}
+
+#define NCT6116D_GPIO_BANK(_base, _ngpio, _regbase, _label)			\
+	{									\
+		.chip = {							\
+			.label            = _label,				\
+			.owner            = THIS_MODULE,			\
+			.get_direction    = nct6116d_gpio_get_direction,	\
+			.direction_input  = nct6116d_gpio_direction_in,		\
+			.get              = nct6116d_gpio_get,			\
+			.direction_output = nct6116d_gpio_direction_out,	\
+			.set              = nct6116d_gpio_set,			\
+			.base             = _base,				\
+			.ngpio            = _ngpio,				\
+			.can_sleep        = false,				\
+		},								\
+		.regbase = _regbase,						\
+	}
+
+static struct nct6116d_gpio_bank nct6116d_gpio_bank[] = {
+	NCT6116D_GPIO_BANK(0, 8, 0xE0, KBUILD_MODNAME "-0"),
+	NCT6116D_GPIO_BANK(10, 8, 0xE4, KBUILD_MODNAME "-1"),
+	NCT6116D_GPIO_BANK(20, 8, 0xE8, KBUILD_MODNAME "-2"),
+	NCT6116D_GPIO_BANK(30, 8, 0xEC, KBUILD_MODNAME "-3"),
+	NCT6116D_GPIO_BANK(40, 8, 0xF0, KBUILD_MODNAME "-4"),
+};
+
+/*
+ * Platform device and driver.
+ */
+
+static int nct6116d_gpio_probe(struct platform_device *pdev)
+{
+	struct nct6116d_sio *sio = pdev->dev.platform_data;
+	struct nct6116d_gpio_data *data;
+	int err;
+	int i;
+
+	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->nr_bank = ARRAY_SIZE(nct6116d_gpio_bank);
+	data->bank = nct6116d_gpio_bank;
+	data->sio = sio;
+
+	platform_set_drvdata(pdev, data);
+
+	/* For each GPIO bank, register a GPIO chip. */
+	for (i = 0; i < data->nr_bank; i++) {
+		struct nct6116d_gpio_bank *bank = &data->bank[i];
+
+		bank->chip.parent = &pdev->dev;
+		bank->data = data;
+
+		err = devm_gpiochip_add_data(&pdev->dev, &bank->chip, bank);
+		if (err)
+			return dev_err_probe(&pdev->dev, err,
+				"Failed to register gpiochip %d\n", i);
+	}
+
+	return 0;
+}
+
+static int __init nct6116d_find(int addr, struct nct6116d_sio *sio)
+{
+	u16 devid;
+	int err;
+
+	err = superio_enter(addr);
+	if (err)
+		return err;
+
+	devid = superio_inw(addr, SIO_CHIPID);
+	superio_exit(addr);
+	switch (devid & SIO_ID_MASK) {
+	case SIO_NCT5104D_ID & SIO_ID_MASK:
+		sio->type = nct5104d;
+		break;
+	case SIO_NCT6106D_ID & SIO_ID_MASK:
+		sio->type = nct6106d;
+		break;
+	case SIO_NCT6116D_ID & SIO_ID_MASK:
+		sio->type = nct6116d;
+		break;
+	case SIO_NCT6122D_ID & SIO_ID_MASK:
+		sio->type = nct6122d;
+		break;
+	default:
+		pr_info("Unsupported device 0x%04x\n", devid);
+		return -ENODEV;
+	}
+	sio->addr = addr;
+
+	pr_info("Found %s at 0x%x chip id 0x%04x\n",
+		nct6116d_names[sio->type], addr, devid);
+	return 0;
+}
+
+static struct platform_device *nct6116d_gpio_pdev;
+
+static int __init
+nct6116d_gpio_device_add(const struct nct6116d_sio *sio)
+{
+	int err;
+
+	nct6116d_gpio_pdev = platform_device_alloc(KBUILD_MODNAME, -1);
+	if (!nct6116d_gpio_pdev)
+		return -ENOMEM;
+
+	err = platform_device_add_data(nct6116d_gpio_pdev, sio, sizeof(*sio));
+	if (err) {
+		pr_err("Platform data allocation failed\n");
+		goto err;
+	}
+
+	err = platform_device_add(nct6116d_gpio_pdev);
+	if (err) {
+		pr_err("Device addition failed\n");
+		goto err;
+	}
+
+	return 0;
+
+err:
+	platform_device_put(nct6116d_gpio_pdev);
+
+	return err;
+}
+
+static struct platform_driver nct6116d_gpio_driver = {
+	.driver = {
+		.name	= KBUILD_MODNAME,
+	},
+	.probe		= nct6116d_gpio_probe,
+};
+
+static int __init nct6116d_gpio_init(void)
+{
+	struct nct6116d_sio sio;
+	int err;
+
+	if (nct6116d_find(0x2e, &sio) &&
+	    nct6116d_find(0x4e, &sio))
+		return -ENODEV;
+
+	err = platform_driver_register(&nct6116d_gpio_driver);
+	if (!err) {
+		err = nct6116d_gpio_device_add(&sio);
+		if (err)
+			platform_driver_unregister(&nct6116d_gpio_driver);
+	}
+
+	return err;
+}
+
+static void __exit nct6116d_gpio_exit(void)
+{
+	platform_device_unregister(nct6116d_gpio_pdev);
+	platform_driver_unregister(&nct6116d_gpio_driver);
+}
+module_init(nct6116d_gpio_init);
+module_exit(nct6116d_gpio_exit);
+
+MODULE_DESCRIPTION("GPIO driver for Nuvoton Super-I/O chips  NCT5104D, NCT6106D, NCT6116D, NCT6122D");
+MODULE_AUTHOR("Tasanakorn Phaipool <tasanakorn@...il.com>");
+MODULE_LICENSE("GPL");
-- 
2.35.1

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