From: Tzuyi Chang <tychang@realtek.com>

This driver enables configuration of GPIO direction, GPIO values, GPIO
debounce settings and handles GPIO interrupts.

Signed-off-by: Tzuyi Chang <tychang@realtek.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
---
v2 to v3 change:
    1. Remove generic compatible and use SoC-specific compatible instead.
    2. Add the missing descriptions for the rtd_gpio_info structure members.
    3. Assign gpio_chip fwnode.
v1 to v2 change:
    1. Remove legacy headers.
    2. Transitioned from OF API to platform_device API.
    3. Use u8 for the offset member within the rtd_gpio_info structure.
    4. Record the size of each array within the rtd_gpio_info structure and
       implement checks to prevent out-of-bounds access.
    5. Use GPIOLIB_IRQCHIP helpers to register interrupts.
    6. Use dynamic allocation for GPIO base.
---
 drivers/gpio/Kconfig    |   9 +
 drivers/gpio/Makefile   |   1 +
 drivers/gpio/gpio-rtd.c | 748 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 758 insertions(+)
 create mode 100644 drivers/gpio/gpio-rtd.c

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index b3a133ed31ee..f0bdf9dbdefc 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -553,6 +553,15 @@ config GPIO_ROCKCHIP
 	help
 	  Say yes here to support GPIO on Rockchip SoCs.
 
+config GPIO_RTD
+	tristate "Realtek DHC GPIO support"
+	depends on ARCH_REALTEK
+	default y
+	select GPIOLIB_IRQCHIP
+	help
+	  Say yes here to support GPIO on Realtek DHC(Digital Home Center)
+	  SoCs.
+
 config GPIO_SAMA5D2_PIOBU
 	tristate "SAMA5D2 PIOBU GPIO support"
 	depends on MFD_SYSCON
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index eb73b5d633eb..16bb40717e87 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -137,6 +137,7 @@ obj-$(CONFIG_GPIO_RDC321X)		+= gpio-rdc321x.o
 obj-$(CONFIG_GPIO_REALTEK_OTTO)		+= gpio-realtek-otto.o
 obj-$(CONFIG_GPIO_REG)			+= gpio-reg.o
 obj-$(CONFIG_GPIO_ROCKCHIP)	+= gpio-rockchip.o
+obj-$(CONFIG_GPIO_RTD)			+= gpio-rtd.o
 obj-$(CONFIG_ARCH_SA1100)		+= gpio-sa1100.o
 obj-$(CONFIG_GPIO_SAMA5D2_PIOBU)	+= gpio-sama5d2-piobu.o
 obj-$(CONFIG_GPIO_SCH311X)		+= gpio-sch311x.o
diff --git a/drivers/gpio/gpio-rtd.c b/drivers/gpio/gpio-rtd.c
new file mode 100644
index 000000000000..f3489b636bc7
--- /dev/null
+++ b/drivers/gpio/gpio-rtd.c
@@ -0,0 +1,748 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Realtek DHC gpio driver
+ *
+ * Copyright (c) 2023 Realtek Semiconductor Corp.
+ */
+
+#include <linux/bitops.h>
+#include <linux/gpio/driver.h>
+#include <linux/interrupt.h>
+#include <linux/irqchip.h>
+#include <linux/irqchip/chained_irq.h>
+#include <linux/irqdomain.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+#include <linux/spinlock.h>
+
+#define RTD_GPIO_DEBOUNCE_1US 0
+#define RTD_GPIO_DEBOUNCE_10US 1
+#define RTD_GPIO_DEBOUNCE_100US 2
+#define RTD_GPIO_DEBOUNCE_1MS 3
+#define RTD_GPIO_DEBOUNCE_10MS 4
+#define RTD_GPIO_DEBOUNCE_20MS 5
+#define RTD_GPIO_DEBOUNCE_30MS 6
+
+enum rtd_gpio_type {
+	RTD_ISO_GPIO = 0,
+	RTD1295_ISO_GPIO,
+	RTD1295_MISC_GPIO,
+	RTD1395_ISO_GPIO,
+	RTD1619_ISO_GPIO,
+};
+
+/**
+ * struct rtd_gpio_info - Specific GPIO register information
+ * @name: GPIO device name
+ * @type: RTD GPIO ID
+ * @gpio_base: GPIO base number
+ * @num_gpios: The number of GPIOs
+ * @dir_offset: Offset for GPIO direction registers
+ * @num_dir: The number of GPIO direction registers
+ * @dato_offset: Offset for GPIO data output registers
+ * @num_dato: The number of GPIO data output registers
+ * @dati_offset: Offset for GPIO data input registers
+ * @num_dati: The number of GPIO data input registers
+ * @ie_offset: Offset for GPIO interrupt enable registers
+ * @num_ie: The number of GPIO interrupt enable registers
+ * @dp_offset: Offset for GPIO detection polarity registers
+ * @num_dp: The number of GPIO detection polarity registers
+ * @gpa_offset: Offset for GPIO assert interrupt status registers
+ * @num_gpa: The number of GPIO assert interrupt status registers
+ * @gpda_offset: Offset for GPIO deassert interrupt status registers
+ * @num_gpda: The number of GPIO deassert interrupt status registers
+ * @deb_offset: Offset for GPIO debounce registers
+ * @num_deb: The number of GPIO debounce registers
+ */
+struct rtd_gpio_info {
+	const char		*name;
+	enum rtd_gpio_type	type;
+	unsigned int		gpio_base;
+	unsigned int		num_gpios;
+	u8			*dir_offset;
+	u8			num_dir;
+	u8			*dato_offset;
+	u8			num_dato;
+	u8			*dati_offset;
+	u8			num_dati;
+	u8			*ie_offset;
+	u8			num_ie;
+	u8			*dp_offset;
+	u8			num_dp;
+	u8			*gpa_offset;
+	u8			num_gpa;
+	u8			*gpda_offset;
+	u8			num_gpda;
+	u8			*deb_offset;
+	u8			num_deb;
+};
+
+struct rtd_gpio {
+	struct platform_device		*pdev;
+	const struct rtd_gpio_info	*info;
+	void __iomem			*base;
+	void __iomem			*irq_base;
+	struct gpio_chip		gpio_chip;
+	unsigned int			irqs[2];
+	spinlock_t			lock;
+};
+
+
+static const struct rtd_gpio_info rtd_iso_gpio_info = {
+	.name		= "rtd_iso_gpio",
+	.type		= RTD_ISO_GPIO,
+	.gpio_base	= 0,
+	.num_gpios	= 82,
+	.dir_offset	= (u8 []){ 0x0, 0x18, 0x2c },
+	.num_dir	= 3,
+	.dato_offset	= (u8 []){ 0x4, 0x1c, 0x30 },
+	.num_dato	= 3,
+	.dati_offset	= (u8 []){ 0x8, 0x20, 0x34 },
+	.num_dati	= 3,
+	.ie_offset	= (u8 []){ 0xc, 0x24, 0x38 },
+	.num_ie		= 3,
+	.dp_offset	= (u8 []){ 0x10, 0x28, 0x3c },
+	.num_dp		= 3,
+	.gpa_offset	= (u8 []){ 0x8, 0xe0, 0x90 },
+	.num_gpa	= 3,
+	.gpda_offset	= (u8 []){ 0xc, 0xe4, 0x94 },
+	.num_gpda	= 3,
+	.deb_offset	= (u8 []){ 0x44, 0x48, 0x4c, 0x50, 0x54, 0x58, 0x5c,
+				   0x60, 0x64, 0x68, 0x6c },
+	.num_deb	= 11,
+};
+
+static const struct rtd_gpio_info rtd1619_iso_gpio_info = {
+	.name		= "rtd1619_iso_gpio",
+	.type		= RTD1619_ISO_GPIO,
+	.gpio_base	= 0,
+	.num_gpios	= 86,
+	.dir_offset	= (u8 []){ 0x0, 0x18, 0x2c },
+	.num_dir	= 3,
+	.dato_offset	= (u8 []){ 0x4, 0x1c, 0x30 },
+	.num_dato	= 3,
+	.dati_offset	= (u8 []){ 0x8, 0x20, 0x34 },
+	.num_dati	= 3,
+	.ie_offset	= (u8 []){ 0xc, 0x24, 0x38 },
+	.num_ie		= 3,
+	.dp_offset	= (u8 []){ 0x10, 0x28, 0x3c },
+	.num_dp		= 3,
+	.gpa_offset	= (u8 []){ 0x8, 0xe0, 0x90 },
+	.num_gpa	= 3,
+	.gpda_offset	= (u8 []){ 0xc, 0xe4, 0x94 },
+	.num_gpda	= 3,
+	.deb_offset	= (u8 []){ 0x44, 0x48, 0x4c, 0x50, 0x54, 0x58, 0x5c,
+				   0x60, 0x64, 0x68, 0x6c },
+	.num_deb	= 11,
+};
+
+static const struct rtd_gpio_info rtd1395_iso_gpio_info = {
+	.name		= "rtd1395_iso_gpio",
+	.type		= RTD1395_ISO_GPIO,
+	.gpio_base	= 0,
+	.num_gpios	= 57,
+	.dir_offset	= (u8 []){ 0x0, 0x18 },
+	.num_dir	= 2,
+	.dato_offset	= (u8 []){ 0x4, 0x1c },
+	.num_dato	= 2,
+	.dati_offset	= (u8 []){ 0x8, 0x20 },
+	.num_dati	= 2,
+	.ie_offset	= (u8 []){ 0xc, 0x24 },
+	.num_ie		= 2,
+	.dp_offset	= (u8 []){ 0x10, 0x28 },
+	.num_dp		= 2,
+	.gpa_offset	= (u8 []){ 0x8, 0xe0 },
+	.num_gpa	= 2,
+	.gpda_offset	= (u8 []){ 0xc, 0xe4 },
+	.num_gpda	= 2,
+	.deb_offset	= (u8 []){ 0x30, 0x34, 0x38, 0x3c, 0x40, 0x44, 0x48, 0x4c },
+	.num_deb	= 8,
+};
+
+static const struct rtd_gpio_info rtd1295_misc_gpio_info = {
+	.name		= "rtd1295_misc_gpio",
+	.type		= RTD1295_ISO_GPIO,
+	.gpio_base	= 0,
+	.num_gpios	= 101,
+	.dir_offset	= (u8 []){ 0x0, 0x4, 0x8, 0xc },
+	.num_dir	= 4,
+	.dato_offset	= (u8 []){ 0x10, 0x14, 0x18, 0x1c },
+	.num_dato	= 4,
+	.dati_offset	= (u8 []){ 0x20, 0x24, 0x28, 0x2c },
+	.num_dati	= 4,
+	.ie_offset	= (u8 []){ 0x30, 0x34, 0x38, 0x3c },
+	.num_ie		= 4,
+	.dp_offset	= (u8 []){ 0x40, 0x44, 0x48, 0x4c },
+	.num_dp		= 4,
+	.gpa_offset	= (u8 []){ 0x40, 0x44, 0xa4, 0xb8 },
+	.num_gpa	= 4,
+	.gpda_offset	= (u8 []){ 0x54, 0x58, 0xa8, 0xbc},
+	.num_gpda	= 4,
+	.deb_offset	= (u8 []){ 0x50 },
+	.num_deb	= 1,
+};
+
+static const struct rtd_gpio_info rtd1295_iso_gpio_info = {
+	.name		= "rtd1295_iso_gpio",
+	.type		= RTD1295_ISO_GPIO,
+	.gpio_base	= 101,
+	.num_gpios	= 35,
+	.dir_offset	= (u8 []){ 0x0, 0x18 },
+	.num_dir	= 2,
+	.dato_offset	= (u8 []){ 0x4, 0x1c },
+	.num_dato	= 2,
+	.dati_offset	= (u8 []){ 0x8, 0x20 },
+	.num_dati	= 2,
+	.ie_offset	= (u8 []){ 0xc, 0x24 },
+	.num_ie		= 2,
+	.dp_offset	= (u8 []){ 0x10, 0x28 },
+	.num_dp		= 2,
+	.gpa_offset	= (u8 []){ 0x8, 0xe0 },
+	.num_gpa	= 2,
+	.gpda_offset	= (u8 []){ 0xc, 0xe4 },
+	.num_gpda	= 2,
+	.deb_offset	= (u8 []){ 0x14 },
+	.num_deb	= 1,
+};
+
+static int rtd_gpio_dir_offset(struct rtd_gpio *data, unsigned int offset)
+{
+	int index = offset / 32;
+
+	if (index > data->info->num_dir)
+		return -EINVAL;
+
+	return data->info->dir_offset[index];
+}
+
+static int rtd_gpio_dato_offset(struct rtd_gpio *data, unsigned int offset)
+{
+	int index = offset / 32;
+
+	if (index > data->info->num_dato)
+		return -EINVAL;
+
+	return data->info->dato_offset[index];
+}
+
+static int rtd_gpio_dati_offset(struct rtd_gpio *data, unsigned int offset)
+{
+	int index = offset / 32;
+
+	if (index > data->info->num_dati)
+		return -EINVAL;
+
+	return data->info->dati_offset[index];
+}
+
+static int rtd_gpio_ie_offset(struct rtd_gpio *data, unsigned int offset)
+{
+	int index = offset / 32;
+
+	if (index > data->info->num_ie)
+		return -EINVAL;
+
+	return data->info->ie_offset[index];
+}
+
+static int rtd_gpio_dp_offset(struct rtd_gpio *data, unsigned int offset)
+{
+	int index = offset / 32;
+
+	if (index > data->info->num_dp)
+		return -EINVAL;
+
+	return data->info->dp_offset[index];
+}
+
+static int rtd_gpio_gpa_offset(struct rtd_gpio *data, unsigned int offset)
+{
+	int index = offset / 31;
+
+	if (index > data->info->num_gpa)
+		return -EINVAL;
+
+	return data->info->gpa_offset[index];
+}
+
+static int rtd_gpio_gpda_offset(struct rtd_gpio *data, unsigned int offset)
+{
+	int index = offset / 31;
+
+	if (index > data->info->num_gpda)
+		return -EINVAL;
+
+	return data->info->gpda_offset[index];
+}
+
+static int rtd_gpio_deb_offset(struct rtd_gpio *data, unsigned int offset)
+{
+	int index = offset / 8;
+
+	if (index > data->info->num_deb)
+		return -EINVAL;
+
+	return data->info->deb_offset[index];
+}
+
+static int rtd_gpio_set_debounce(struct gpio_chip *chip, unsigned int offset,
+				   unsigned int debounce)
+{
+	struct rtd_gpio *data = gpiochip_get_data(chip);
+	unsigned int write_en;
+	unsigned long flags;
+	unsigned int shift;
+	int reg_offset;
+	u32 deb_val;
+	u32 val;
+
+	switch (debounce) {
+	case 1:
+		deb_val = RTD_GPIO_DEBOUNCE_1US;
+		break;
+	case 10:
+		deb_val = RTD_GPIO_DEBOUNCE_10US;
+		break;
+	case 100:
+		deb_val = RTD_GPIO_DEBOUNCE_100US;
+		break;
+	case 1000:
+		deb_val = RTD_GPIO_DEBOUNCE_1MS;
+		break;
+	case 10000:
+		deb_val = RTD_GPIO_DEBOUNCE_10MS;
+		break;
+	case 20000:
+		deb_val = RTD_GPIO_DEBOUNCE_20MS;
+		break;
+	case 30000:
+		deb_val = RTD_GPIO_DEBOUNCE_30MS;
+		break;
+	default:
+		return -ENOTSUPP;
+	}
+
+	if (data->info->type == RTD1295_ISO_GPIO) {
+		reg_offset = rtd_gpio_deb_offset(data, 0);
+		if (reg_offset < 0)
+			return reg_offset;
+		shift = 0;
+		deb_val += 1;
+		write_en = BIT(shift + 3);
+	} else if (data->info->type == RTD1295_MISC_GPIO) {
+		reg_offset = rtd_gpio_deb_offset(data, 0);
+		if (reg_offset < 0)
+			return reg_offset;
+		shift = (offset >> 4) * 4;
+		deb_val += 1;
+		write_en = BIT(shift + 3);
+	} else {
+		reg_offset = rtd_gpio_deb_offset(data, offset);
+		if (reg_offset < 0)
+			return reg_offset;
+		shift = (offset % 8) * 4;
+		write_en = BIT(shift + 3);
+	}
+	val = (deb_val << shift) | write_en;
+
+	spin_lock_irqsave(&data->lock, flags);
+	writel_relaxed(val, data->base + reg_offset);
+	spin_unlock_irqrestore(&data->lock, flags);
+
+	return 0;
+}
+
+static int rtd_gpio_set_config(struct gpio_chip *chip, unsigned int offset,
+				 unsigned long config)
+{
+	int debounce;
+
+	switch (pinconf_to_config_param(config)) {
+	case PIN_CONFIG_BIAS_DISABLE:
+	case PIN_CONFIG_BIAS_PULL_UP:
+	case PIN_CONFIG_BIAS_PULL_DOWN:
+		return gpiochip_generic_config(chip, offset, config);
+	case PIN_CONFIG_INPUT_DEBOUNCE:
+		debounce = pinconf_to_config_argument(config);
+		return rtd_gpio_set_debounce(chip, offset, debounce);
+	default:
+		return -ENOTSUPP;
+	}
+}
+
+static int rtd_gpio_get_direction(struct gpio_chip *chip, unsigned int offset)
+{
+	struct rtd_gpio *data = gpiochip_get_data(chip);
+	unsigned long flags;
+	int reg_offset;
+	u32 val;
+
+	reg_offset = rtd_gpio_dir_offset(data, offset);
+	if (reg_offset < 0)
+		return reg_offset;
+
+	spin_lock_irqsave(&data->lock, flags);
+
+	val = readl_relaxed(data->base + reg_offset);
+	val &= BIT(offset % 32);
+
+	spin_unlock_irqrestore(&data->lock, flags);
+
+	return val ? GPIO_LINE_DIRECTION_OUT : GPIO_LINE_DIRECTION_IN;
+}
+
+static int rtd_gpio_set_direction(struct gpio_chip *chip, unsigned int offset, bool out)
+{
+	struct rtd_gpio *data = gpiochip_get_data(chip);
+	u32 mask = BIT(offset % 32);
+	unsigned long flags;
+	int reg_offset;
+	u32 val;
+
+	reg_offset = rtd_gpio_dir_offset(data, offset);
+	if (reg_offset < 0)
+		return reg_offset;
+
+	spin_lock_irqsave(&data->lock, flags);
+
+	val = readl_relaxed(data->base + reg_offset);
+	if (out)
+		val |= mask;
+	else
+		val &= ~mask;
+	writel_relaxed(val, data->base + reg_offset);
+
+	spin_unlock_irqrestore(&data->lock, flags);
+
+	return 0;
+}
+
+static int rtd_gpio_direction_input(struct gpio_chip *chip, unsigned int offset)
+{
+	return rtd_gpio_set_direction(chip, offset, false);
+}
+
+static int rtd_gpio_direction_output(struct gpio_chip *chip, unsigned int offset, int value)
+{
+	chip->set(chip, offset, value);
+
+	return rtd_gpio_set_direction(chip, offset, true);
+}
+
+static void rtd_gpio_set(struct gpio_chip *chip, unsigned int offset, int value)
+{
+	struct rtd_gpio *data = gpiochip_get_data(chip);
+	u32 mask = BIT(offset % 32);
+	unsigned long flags;
+	int dato_reg_offset;
+	u32 val;
+
+	dato_reg_offset = rtd_gpio_dato_offset(data, offset);
+	if (dato_reg_offset < 0)
+		return;
+
+	spin_lock_irqsave(&data->lock, flags);
+
+	val = readl_relaxed(data->base + dato_reg_offset);
+	if (value)
+		val |= mask;
+	else
+		val &= ~mask;
+	writel_relaxed(val, data->base + dato_reg_offset);
+
+	spin_unlock_irqrestore(&data->lock, flags);
+}
+
+static int rtd_gpio_get(struct gpio_chip *chip, unsigned int offset)
+{
+	struct rtd_gpio *data = gpiochip_get_data(chip);
+	int dir_reg_offset, dat_reg_offset;
+	unsigned long flags;
+	u32 val;
+
+	dir_reg_offset = rtd_gpio_dir_offset(data, offset);
+	if (dir_reg_offset < 0)
+		return dir_reg_offset;
+
+	spin_lock_irqsave(&data->lock, flags);
+
+	val = readl_relaxed(data->base + dir_reg_offset);
+	val &= BIT(offset % 32);
+	dat_reg_offset = val ?
+			 rtd_gpio_dato_offset(data, offset) : rtd_gpio_dati_offset(data, offset);
+
+	val = readl_relaxed(data->base + dat_reg_offset);
+	val >>= offset % 32;
+	val &= 0x1;
+
+	spin_unlock_irqrestore(&data->lock, flags);
+
+	return val;
+}
+
+static bool rtd_gpio_check_ie(struct rtd_gpio *data, int irq)
+{
+	int mask = BIT(irq % 32);
+	int ie_reg_offset;
+	u32 enable;
+
+	ie_reg_offset = rtd_gpio_ie_offset(data, irq);
+	if (ie_reg_offset < 0)
+		return ie_reg_offset;
+	enable = readl_relaxed(data->base + ie_reg_offset);
+
+	return enable & mask;
+}
+
+static void rtd_gpio_irq_handle(struct irq_desc *desc)
+{
+	int (*get_reg_offset)(struct rtd_gpio *gpio, unsigned int offset);
+	struct rtd_gpio *data = irq_desc_get_handler_data(desc);
+	struct irq_domain *domain = data->gpio_chip.irq.domain;
+	struct irq_chip *chip = irq_desc_get_chip(desc);
+	unsigned int irq = irq_desc_get_irq(desc);
+	int reg_offset;
+	u32 status;
+	int hwirq;
+	int i;
+	int j;
+
+	chained_irq_enter(chip, desc);
+
+	if (irq == data->irqs[0])
+		get_reg_offset = &rtd_gpio_gpa_offset;
+	else if (irq == data->irqs[1])
+		get_reg_offset = &rtd_gpio_gpda_offset;
+
+	for (i = 0; i < data->info->num_gpios; i = i + 31) {
+		reg_offset = get_reg_offset(data, i);
+		if (reg_offset < 0)
+			return;
+
+		status = readl_relaxed(data->irq_base + reg_offset) >> 1;
+		writel_relaxed(status << 1, data->irq_base + reg_offset);
+
+		while (status) {
+			j = __ffs(status);
+			status &= ~BIT(j);
+			hwirq = i + j;
+			if (rtd_gpio_check_ie(data, hwirq)) {
+				int girq = irq_find_mapping(domain, hwirq);
+				u32 irq_type = irq_get_trigger_type(girq);
+
+				if ((irq == data->irqs[1]) && ((irq_type & IRQ_TYPE_SENSE_MASK) !=
+					IRQ_TYPE_EDGE_BOTH))
+					break;
+				generic_handle_irq(girq);
+			}
+		}
+	}
+
+	chained_irq_exit(chip, desc);
+}
+
+static void rtd_gpio_enable_irq(struct irq_data *d)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+	struct rtd_gpio *data = gpiochip_get_data(gc);
+	u32 clr_mask = BIT(d->hwirq % 31) << 1;
+	u32 ie_mask = BIT(d->hwirq % 32);
+	unsigned long flags;
+	int gpda_reg_offset;
+	int gpa_reg_offset;
+	int ie_reg_offset;
+	u32 val;
+
+	ie_reg_offset = rtd_gpio_ie_offset(data, d->hwirq);
+	if (ie_reg_offset < 0)
+		return;
+	gpa_reg_offset = rtd_gpio_gpa_offset(data, d->hwirq);
+	if (gpa_reg_offset < 0)
+		return;
+	gpda_reg_offset = rtd_gpio_gpda_offset(data, d->hwirq);
+	if (gpda_reg_offset < 0)
+		return;
+
+	spin_lock_irqsave(&data->lock, flags);
+
+	writel_relaxed(clr_mask, data->irq_base + gpa_reg_offset);
+	writel_relaxed(clr_mask, data->irq_base + gpda_reg_offset);
+
+	val = readl_relaxed(data->base + ie_reg_offset);
+	val |= ie_mask;
+	writel_relaxed(val, data->base + ie_reg_offset);
+
+	spin_unlock_irqrestore(&data->lock, flags);
+
+}
+
+static void rtd_gpio_disable_irq(struct irq_data *d)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+	struct rtd_gpio *data = gpiochip_get_data(gc);
+	u32 ie_mask = BIT(d->hwirq % 32);
+	unsigned long flags;
+	int ie_reg_offset;
+	u32 val;
+
+	ie_reg_offset = rtd_gpio_ie_offset(data, d->hwirq);
+	if (ie_reg_offset < 0)
+		return;
+
+	spin_lock_irqsave(&data->lock, flags);
+
+	val = readl_relaxed(data->base + ie_reg_offset);
+	val &= ~ie_mask;
+	writel_relaxed(val, data->base + ie_reg_offset);
+
+	spin_unlock_irqrestore(&data->lock, flags);
+}
+
+static int rtd_gpio_irq_set_type(struct irq_data *d, unsigned int type)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+	struct rtd_gpio *data = gpiochip_get_data(gc);
+	u32 mask = BIT(d->hwirq % 32);
+	unsigned long flags;
+	int dp_reg_offset;
+	bool polarity;
+	u32 val;
+
+	dp_reg_offset = rtd_gpio_dp_offset(data, d->hwirq);
+	if (dp_reg_offset < 0)
+		return dp_reg_offset;
+
+	switch (type & IRQ_TYPE_SENSE_MASK) {
+	case IRQ_TYPE_EDGE_RISING:
+		polarity = 1;
+		break;
+
+	case IRQ_TYPE_EDGE_FALLING:
+		polarity = 0;
+		break;
+
+	case IRQ_TYPE_EDGE_BOTH:
+		polarity = 1;
+		break;
+
+	default:
+		return -EINVAL;
+	}
+
+	spin_lock_irqsave(&data->lock, flags);
+
+	val = readl_relaxed(data->base + dp_reg_offset);
+	if (polarity)
+		val |= mask;
+	else
+		val &= ~mask;
+	writel_relaxed(val, data->base + dp_reg_offset);
+
+	spin_unlock_irqrestore(&data->lock, flags);
+
+	return 0;
+}
+
+static const struct irq_chip rtd_gpio_irq_chip = {
+	.name = "rtd-gpio",
+	.irq_enable = rtd_gpio_enable_irq,
+	.irq_disable = rtd_gpio_disable_irq,
+	.irq_set_type = rtd_gpio_irq_set_type,
+	.flags = IRQCHIP_IMMUTABLE,
+};
+
+static const struct of_device_id rtd_gpio_of_matches[] = {
+	{ .compatible = "realtek,rtd1295-misc-gpio", .data = &rtd1295_misc_gpio_info },
+	{ .compatible = "realtek,rtd1295-iso-gpio", .data = &rtd1295_iso_gpio_info },
+	{ .compatible = "realtek,rtd1395-iso-gpio", .data = &rtd1395_iso_gpio_info },
+	{ .compatible = "realtek,rtd1619-iso-gpio", .data = &rtd1619_iso_gpio_info },
+	{ .compatible = "realtek,rtd1319-iso-gpio", .data = &rtd_iso_gpio_info },
+	{ .compatible = "realtek,rtd1619b-iso-gpio", .data = &rtd_iso_gpio_info },
+	{ .compatible = "realtek,rtd1319d-iso-gpio", .data = &rtd_iso_gpio_info },
+	{ .compatible = "realtek,rtd1315e-iso-gpio", .data = &rtd_iso_gpio_info },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, rtd_gpio_of_matches);
+
+static int rtd_gpio_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct gpio_irq_chip *irq_chip;
+	struct rtd_gpio *data;
+
+	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->irqs[0] = platform_get_irq(pdev, 0);
+	if (data->irqs[0] < 0)
+		return data->irqs[0];
+
+	data->irqs[1] = platform_get_irq(pdev, 1);
+	if (data->irqs[1] < 0)
+		return data->irqs[1];
+
+	data->info = device_get_match_data(dev);
+	if (!data->info)
+		return -EINVAL;
+
+	spin_lock_init(&data->lock);
+
+	data->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(data->base))
+		return PTR_ERR(data->base);
+
+	data->irq_base = devm_platform_ioremap_resource(pdev, 1);
+	if (IS_ERR(data->irq_base))
+		return PTR_ERR(data->irq_base);
+
+	data->gpio_chip.label = dev_name(&pdev->dev);
+	data->gpio_chip.base = -1;
+	data->gpio_chip.ngpio = data->info->num_gpios;
+	data->gpio_chip.request = gpiochip_generic_request;
+	data->gpio_chip.free = gpiochip_generic_free;
+	data->gpio_chip.get_direction = rtd_gpio_get_direction;
+	data->gpio_chip.direction_input = rtd_gpio_direction_input;
+	data->gpio_chip.direction_output = rtd_gpio_direction_output;
+	data->gpio_chip.set = rtd_gpio_set;
+	data->gpio_chip.get = rtd_gpio_get;
+	data->gpio_chip.set_config = rtd_gpio_set_config;
+	data->gpio_chip.fwnode = dev_fwnode(&pdev->dev);
+
+	irq_chip = &data->gpio_chip.irq;
+	irq_chip->handler = handle_simple_irq;
+	irq_chip->default_type = IRQ_TYPE_NONE;
+	irq_chip->parent_handler = rtd_gpio_irq_handle;
+	irq_chip->parent_handler_data = data;
+	irq_chip->num_parents = 2;
+	irq_chip->parents = data->irqs;
+
+	gpio_irq_chip_set_chip(irq_chip, &rtd_gpio_irq_chip);
+
+	return devm_gpiochip_add_data(&pdev->dev, &data->gpio_chip, data);
+}
+
+static struct platform_driver rtd_gpio_platform_driver = {
+	.driver = {
+		.name = "gpio-rtd",
+		.of_match_table = rtd_gpio_of_matches,
+	},
+	.probe = rtd_gpio_probe,
+};
+
+static int rtd_gpio_init(void)
+{
+	return platform_driver_register(&rtd_gpio_platform_driver);
+}
+
+subsys_initcall(rtd_gpio_init);
+
+static void __exit rtd_gpio_exit(void)
+{
+	platform_driver_unregister(&rtd_gpio_platform_driver);
+}
+module_exit(rtd_gpio_exit);
+
+MODULE_DESCRIPTION("Realtek DHC SoC gpio driver");
+MODULE_LICENSE("GPL v2");
-- 
2.43.0

On Thu, Dec 07, 2023 at 06:07:23PM +0800, TY Chang wrote:
> From: Tzuyi Chang <tychang@realtek.com>
> 
> This driver enables configuration of GPIO direction, GPIO values, GPIO
> debounce settings and handles GPIO interrupts.

Why gpio-regmap can't be used?

...

> +struct rtd_gpio_info {

> +	u8			*dir_offset;
> +	u8			num_dir;
> +	u8			*dato_offset;
> +	u8			num_dato;
> +	u8			*dati_offset;
> +	u8			num_dati;
> +	u8			*ie_offset;
> +	u8			num_ie;
> +	u8			*dp_offset;
> +	u8			num_dp;
> +	u8			*gpa_offset;
> +	u8			num_gpa;
> +	u8			*gpda_offset;
> +	u8			num_gpda;
> +	u8			*deb_offset;
> +	u8			num_deb;

A lot of wasted space. Can you group pointers followed by u8 members?
Note, use `pahole` tool to check the struct layout in C.

> +};

...

> +struct rtd_gpio {
> +	struct platform_device		*pdev;

Why

	struct device *dev;

is not suffice?

> +	const struct rtd_gpio_info	*info;
> +	void __iomem			*base;
> +	void __iomem			*irq_base;

> +	struct gpio_chip		gpio_chip;

Make this to be the first member, it might reduce some code
(due to pointer arithmetics).

> +	unsigned int			irqs[2];
> +	spinlock_t			lock;
> +};
> +
> +

One blank line is enough.

...

> +static const struct rtd_gpio_info rtd_iso_gpio_info = {
> +	.name		= "rtd_iso_gpio",
> +	.type		= RTD_ISO_GPIO,
> +	.gpio_base	= 0,
> +	.num_gpios	= 82,
> +	.dir_offset	= (u8 []){ 0x0, 0x18, 0x2c },
> +	.num_dir	= 3,
> +	.dato_offset	= (u8 []){ 0x4, 0x1c, 0x30 },
> +	.num_dato	= 3,
> +	.dati_offset	= (u8 []){ 0x8, 0x20, 0x34 },
> +	.num_dati	= 3,
> +	.ie_offset	= (u8 []){ 0xc, 0x24, 0x38 },
> +	.num_ie		= 3,
> +	.dp_offset	= (u8 []){ 0x10, 0x28, 0x3c },
> +	.num_dp		= 3,
> +	.gpa_offset	= (u8 []){ 0x8, 0xe0, 0x90 },
> +	.num_gpa	= 3,
> +	.gpda_offset	= (u8 []){ 0xc, 0xe4, 0x94 },
> +	.num_gpda	= 3,
> +	.deb_offset	= (u8 []){ 0x44, 0x48, 0x4c, 0x50, 0x54, 0x58, 0x5c,
> +				   0x60, 0x64, 0x68, 0x6c },
> +	.num_deb	= 11,

Use ARRAY_SIZE() from array_size.h for all num_* assignments.

> +};

...

> +static const struct rtd_gpio_info rtd1619_iso_gpio_info = {

Ditto.

> +};

...

> +static const struct rtd_gpio_info rtd1395_iso_gpio_info = {

Ditto.

> +};
> +
> +static const struct rtd_gpio_info rtd1295_misc_gpio_info = {

Ditto.

> +};
> +
> +static const struct rtd_gpio_info rtd1295_iso_gpio_info = {

Ditto.

> +};

...

> +static int rtd_gpio_dir_offset(struct rtd_gpio *data, unsigned int offset)
> +{
> +	int index = offset / 32;

> +	if (index > data->info->num_dir)
> +		return -EINVAL;

When this conditional can be true?
Same Q to the similar checks over the code.

> +	return data->info->dir_offset[index];
> +}

...

> +	if (data->info->type == RTD1295_ISO_GPIO) {
> +		reg_offset = rtd_gpio_deb_offset(data, 0);
> +		if (reg_offset < 0)
> +			return reg_offset;
> +		shift = 0;
> +		deb_val += 1;
> +		write_en = BIT(shift + 3);
> +	} else if (data->info->type == RTD1295_MISC_GPIO) {
> +		reg_offset = rtd_gpio_deb_offset(data, 0);
> +		if (reg_offset < 0)
> +			return reg_offset;
> +		shift = (offset >> 4) * 4;
> +		deb_val += 1;
> +		write_en = BIT(shift + 3);
> +	} else {
> +		reg_offset = rtd_gpio_deb_offset(data, offset);
> +		if (reg_offset < 0)
> +			return reg_offset;
> +		shift = (offset % 8) * 4;
> +		write_en = BIT(shift + 3);
> +	}

You should probably have kind of chip_info constant structure that goes via
driver_data and will have a callback, so, here you will call one and get all
three at once:
 - register offset;
 - shift
 - updated debounce value

...

> +static int rtd_gpio_get_direction(struct gpio_chip *chip, unsigned int offset)
> +{
> +	struct rtd_gpio *data = gpiochip_get_data(chip);
> +	unsigned long flags;
> +	int reg_offset;
> +	u32 val;
> +
> +	reg_offset = rtd_gpio_dir_offset(data, offset);
> +	if (reg_offset < 0)
> +		return reg_offset;

> +	spin_lock_irqsave(&data->lock, flags);

So, is your IRQ chip going to work with CONFIG_PREEMT_RT?

> +	val = readl_relaxed(data->base + reg_offset);

> +	val &= BIT(offset % 32);

Why this is is under lock?

> +	spin_unlock_irqrestore(&data->lock, flags);
> +
> +	return val ? GPIO_LINE_DIRECTION_OUT : GPIO_LINE_DIRECTION_IN;
> +}

...

> +static int rtd_gpio_set_direction(struct gpio_chip *chip, unsigned int offset, bool out)
> +{

> +	unsigned long flags;


> +	spin_lock_irqsave(&data->lock, flags);


> +	spin_unlock_irqrestore(&data->lock, flags);

Consider to utilise guard() / scoped_guard() from cleanup.h.

> +}

...

> +static int rtd_gpio_direction_output(struct gpio_chip *chip, unsigned int offset, int value)
> +{

> +	chip->set(chip, offset, value);

Why? Can't you call the function by its name directly?

> +
> +	return rtd_gpio_set_direction(chip, offset, true);
> +}

...

> +static int rtd_gpio_get(struct gpio_chip *chip, unsigned int offset)
> +{
> +	struct rtd_gpio *data = gpiochip_get_data(chip);
> +	int dir_reg_offset, dat_reg_offset;
> +	unsigned long flags;
> +	u32 val;
> +
> +	dir_reg_offset = rtd_gpio_dir_offset(data, offset);
> +	if (dir_reg_offset < 0)
> +		return dir_reg_offset;
> +
> +	spin_lock_irqsave(&data->lock, flags);
> +
> +	val = readl_relaxed(data->base + dir_reg_offset);
> +	val &= BIT(offset % 32);

> +	dat_reg_offset = val ?
> +			 rtd_gpio_dato_offset(data, offset) : rtd_gpio_dati_offset(data, offset);

Can't you have the direction be cached and already know which offset to use
even before the lock?

> +	val = readl_relaxed(data->base + dat_reg_offset);

> +	val >>= offset % 32;
> +	val &= 0x1;

Why were these operations done under the lock?

> +	spin_unlock_irqrestore(&data->lock, flags);
> +
> +	return val;
> +}

...

> +static void rtd_gpio_irq_handle(struct irq_desc *desc)
> +{
> +	int (*get_reg_offset)(struct rtd_gpio *gpio, unsigned int offset);
> +	struct rtd_gpio *data = irq_desc_get_handler_data(desc);
> +	struct irq_domain *domain = data->gpio_chip.irq.domain;
> +	struct irq_chip *chip = irq_desc_get_chip(desc);
> +	unsigned int irq = irq_desc_get_irq(desc);
> +	int reg_offset;
> +	u32 status;

> +	int hwirq;

Why signed?

> +	int i;
> +	int j;
> +
> +	chained_irq_enter(chip, desc);

> +	if (irq == data->irqs[0])
> +		get_reg_offset = &rtd_gpio_gpa_offset;
> +	else if (irq == data->irqs[1])
> +		get_reg_offset = &rtd_gpio_gpda_offset;

Can't it be done before entering into chained IRQ handler?

> +	for (i = 0; i < data->info->num_gpios; i = i + 31) {

31 ?!  In any case i += 31 is simply shorter.

> +		reg_offset = get_reg_offset(data, i);
> +		if (reg_offset < 0)
> +			return;
> +
> +		status = readl_relaxed(data->irq_base + reg_offset) >> 1;
> +		writel_relaxed(status << 1, data->irq_base + reg_offset);

> +		while (status) {
> +			j = __ffs(status);
> +			status &= ~BIT(j);

NIH for_each_set_bit()

> +			hwirq = i + j;
> +			if (rtd_gpio_check_ie(data, hwirq)) {
> +				int girq = irq_find_mapping(domain, hwirq);
> +				u32 irq_type = irq_get_trigger_type(girq);
> +
> +				if ((irq == data->irqs[1]) && ((irq_type & IRQ_TYPE_SENSE_MASK) !=
> +					IRQ_TYPE_EDGE_BOTH))
> +					break;

> +				generic_handle_irq(girq);

Why you can't use generic_handle_domain_irq()?

> +			}
> +		}
> +	}
> +
> +	chained_irq_exit(chip, desc);
> +}

...

> +	u32 mask = BIT(d->hwirq % 32);

Use proper type and getter for hwirq. It's mentioned in the Documentation.

...

> +static const struct irq_chip rtd_gpio_irq_chip = {
> +	.name = "rtd-gpio",
> +	.irq_enable = rtd_gpio_enable_irq,
> +	.irq_disable = rtd_gpio_disable_irq,
> +	.irq_set_type = rtd_gpio_irq_set_type,

> +	.flags = IRQCHIP_IMMUTABLE,

Is it? You seems missed something to fulfill the immutability requirements.
Please consult with the Documentation, it's all written there.

> +};

...

> +static const struct of_device_id rtd_gpio_of_matches[] = {
> +	{ .compatible = "realtek,rtd1295-misc-gpio", .data = &rtd1295_misc_gpio_info },
> +	{ .compatible = "realtek,rtd1295-iso-gpio", .data = &rtd1295_iso_gpio_info },
> +	{ .compatible = "realtek,rtd1395-iso-gpio", .data = &rtd1395_iso_gpio_info },
> +	{ .compatible = "realtek,rtd1619-iso-gpio", .data = &rtd1619_iso_gpio_info },
> +	{ .compatible = "realtek,rtd1319-iso-gpio", .data = &rtd_iso_gpio_info },
> +	{ .compatible = "realtek,rtd1619b-iso-gpio", .data = &rtd_iso_gpio_info },
> +	{ .compatible = "realtek,rtd1319d-iso-gpio", .data = &rtd_iso_gpio_info },
> +	{ .compatible = "realtek,rtd1315e-iso-gpio", .data = &rtd_iso_gpio_info },

> +	{ },

No comma in the terminator entry.

> +};
> +MODULE_DEVICE_TABLE(of, rtd_gpio_of_matches);

Move all these closer to its user (struct platform_device below).

...

> +	data->gpio_chip.label = dev_name(&pdev->dev);

dev

...

> +	data->gpio_chip.fwnode = dev_fwnode(&pdev->dev);

dev

But why setting parent device is not suffice?

...

> +static int rtd_gpio_init(void)
> +{
> +	return platform_driver_register(&rtd_gpio_platform_driver);
> +}

> +

Unneeded blank line.

> +subsys_initcall(rtd_gpio_init);

Why? Anything that is not on standard initcall must be justified.

-- 
With Best Regards,
Andy Shevchenko

Hi Andy,

Thank you for the review.

>On Thu, Dec 07, 2023 at 06:07:23PM +0800, TY Chang wrote:
>> From: Tzuyi Chang <tychang@realtek.com>
>>
>> This driver enables configuration of GPIO direction, GPIO values, GPIO
>> debounce settings and handles GPIO interrupts.
>
>Why gpio-regmap can't be used?
>

I will try to use gpio-remap in the next version.

>...
>
>> +struct rtd_gpio_info {
>
>> +     u8                      *dir_offset;
>> +     u8                      num_dir;
>> +     u8                      *dato_offset;
>> +     u8                      num_dato;
>> +     u8                      *dati_offset;
>> +     u8                      num_dati;
>> +     u8                      *ie_offset;
>> +     u8                      num_ie;
>> +     u8                      *dp_offset;
>> +     u8                      num_dp;
>> +     u8                      *gpa_offset;
>> +     u8                      num_gpa;
>> +     u8                      *gpda_offset;
>> +     u8                      num_gpda;
>> +     u8                      *deb_offset;
>> +     u8                      num_deb;
>
>A lot of wasted space. Can you group pointers followed by u8 members?
>Note, use `pahole` tool to check the struct layout in C.
>

I will revise it in the next version.

>> +};
>
>...
>
>> +struct rtd_gpio {
>> +     struct platform_device          *pdev;
>
>Why
>
>        struct device *dev;
>
>is not suffice?
>

I will remove the pdev.

>> +     const struct rtd_gpio_info      *info;
>> +     void __iomem                    *base;
>> +     void __iomem                    *irq_base;
>
>> +     struct gpio_chip                gpio_chip;
>
>Make this to be the first member, it might reduce some code (due to pointer
>arithmetics).
>

I will move the gpio_chip to the first member.

>> +     unsigned int                    irqs[2];
>> +     spinlock_t                      lock;
>> +};
>> +
>> +
>
>One blank line is enough.
>

I will remove it.

>...
>
>> +static const struct rtd_gpio_info rtd_iso_gpio_info = {
>> +     .name           = "rtd_iso_gpio",
>> +     .type           = RTD_ISO_GPIO,
>> +     .gpio_base      = 0,
>> +     .num_gpios      = 82,
>> +     .dir_offset     = (u8 []){ 0x0, 0x18, 0x2c },
>> +     .num_dir        = 3,
>> +     .dato_offset    = (u8 []){ 0x4, 0x1c, 0x30 },
>> +     .num_dato       = 3,
>> +     .dati_offset    = (u8 []){ 0x8, 0x20, 0x34 },
>> +     .num_dati       = 3,
>> +     .ie_offset      = (u8 []){ 0xc, 0x24, 0x38 },
>> +     .num_ie         = 3,
>> +     .dp_offset      = (u8 []){ 0x10, 0x28, 0x3c },
>> +     .num_dp         = 3,
>> +     .gpa_offset     = (u8 []){ 0x8, 0xe0, 0x90 },
>> +     .num_gpa        = 3,
>> +     .gpda_offset    = (u8 []){ 0xc, 0xe4, 0x94 },
>> +     .num_gpda       = 3,
>> +     .deb_offset     = (u8 []){ 0x44, 0x48, 0x4c, 0x50, 0x54, 0x58, 0x5c,
>> +                                0x60, 0x64, 0x68, 0x6c },
>> +     .num_deb        = 11,
>
>Use ARRAY_SIZE() from array_size.h for all num_* assignments.
>

I will revise it.

>> +};
>
>...
>
>> +static const struct rtd_gpio_info rtd1619_iso_gpio_info = {
>
>Ditto.
>
>> +};
>
>...
>
>> +static const struct rtd_gpio_info rtd1395_iso_gpio_info = {
>
>Ditto.
>
>> +};
>> +
>> +static const struct rtd_gpio_info rtd1295_misc_gpio_info = {
>
>Ditto.
>
>> +};
>> +
>> +static const struct rtd_gpio_info rtd1295_iso_gpio_info = {
>
>Ditto.
>
>> +};
>
>...
>
>> +static int rtd_gpio_dir_offset(struct rtd_gpio *data, unsigned int
>> +offset) {
>> +     int index = offset / 32;
>
>> +     if (index > data->info->num_dir)
>> +             return -EINVAL;
>
>When this conditional can be true?
>Same Q to the similar checks over the code.
>

It is only to check if the offset value is missing in the rtd_gpio_info. I'm uncertain
about the necessity of these checks. If they are not necessary, I will remove
the num_* members in the rtd_gpio_info structure along with these checks. 

>> +     return data->info->dir_offset[index]; }
>
>...
>
>> +     if (data->info->type == RTD1295_ISO_GPIO) {
>> +             reg_offset = rtd_gpio_deb_offset(data, 0);
>> +             if (reg_offset < 0)
>> +                     return reg_offset;
>> +             shift = 0;
>> +             deb_val += 1;
>> +             write_en = BIT(shift + 3);
>> +     } else if (data->info->type == RTD1295_MISC_GPIO) {
>> +             reg_offset = rtd_gpio_deb_offset(data, 0);
>> +             if (reg_offset < 0)
>> +                     return reg_offset;
>> +             shift = (offset >> 4) * 4;
>> +             deb_val += 1;
>> +             write_en = BIT(shift + 3);
>> +     } else {
>> +             reg_offset = rtd_gpio_deb_offset(data, offset);
>> +             if (reg_offset < 0)
>> +                     return reg_offset;
>> +             shift = (offset % 8) * 4;
>> +             write_en = BIT(shift + 3);
>> +     }
>
>You should probably have kind of chip_info constant structure that goes via
>driver_data and will have a callback, so, here you will call one and get all three
>at once:
> - register offset;
> - shift
> - updated debounce value
>

I will add a callback in the struct rtd_gpio_info to get these values.

>...
>
>> +static int rtd_gpio_get_direction(struct gpio_chip *chip, unsigned
>> +int offset) {
>> +     struct rtd_gpio *data = gpiochip_get_data(chip);
>> +     unsigned long flags;
>> +     int reg_offset;
>> +     u32 val;
>> +
>> +     reg_offset = rtd_gpio_dir_offset(data, offset);
>> +     if (reg_offset < 0)
>> +             return reg_offset;
>
>> +     spin_lock_irqsave(&data->lock, flags);
>
>So, is your IRQ chip going to work with CONFIG_PREEMT_RT?
>

No, we do not enable CONFIG_PREEMT_RT. However, a custom driver might change
the GPIO status in the ISR. I will utilize raw_spinlock instead and only lock
the write operations.

>> +     val = readl_relaxed(data->base + reg_offset);
>
>> +     val &= BIT(offset % 32);
>
>Why this is is under lock?
>

I'll move it outside of the lock.

>> +     spin_unlock_irqrestore(&data->lock, flags);
>> +
>> +     return val ? GPIO_LINE_DIRECTION_OUT :
>GPIO_LINE_DIRECTION_IN; }
>
>...
>
>> +static int rtd_gpio_set_direction(struct gpio_chip *chip, unsigned
>> +int offset, bool out) {
>
>> +     unsigned long flags;
>
>
>> +     spin_lock_irqsave(&data->lock, flags);
>
>
>> +     spin_unlock_irqrestore(&data->lock, flags);
>
>Consider to utilise guard() / scoped_guard() from cleanup.h.
>

I will try to use these macros.

>> +}
>
>...
>
>> +static int rtd_gpio_direction_output(struct gpio_chip *chip, unsigned
>> +int offset, int value) {
>
>> +     chip->set(chip, offset, value);
>
>Why? Can't you call the function by its name directly?
>

I will revise it.

>> +
>> +     return rtd_gpio_set_direction(chip, offset, true); }
>
>...
>
>> +static int rtd_gpio_get(struct gpio_chip *chip, unsigned int offset)
>> +{
>> +     struct rtd_gpio *data = gpiochip_get_data(chip);
>> +     int dir_reg_offset, dat_reg_offset;
>> +     unsigned long flags;
>> +     u32 val;
>> +
>> +     dir_reg_offset = rtd_gpio_dir_offset(data, offset);
>> +     if (dir_reg_offset < 0)
>> +             return dir_reg_offset;
>> +
>> +     spin_lock_irqsave(&data->lock, flags);
>> +
>> +     val = readl_relaxed(data->base + dir_reg_offset);
>> +     val &= BIT(offset % 32);
>
>> +     dat_reg_offset = val ?
>> +                      rtd_gpio_dato_offset(data, offset) :
>> + rtd_gpio_dati_offset(data, offset);
>
>Can't you have the direction be cached and already know which offset to use
>even before the lock?
>

I will move these codes outside of the lock.

>> +     val = readl_relaxed(data->base + dat_reg_offset);
>
>> +     val >>= offset % 32;
>> +     val &= 0x1;
>
>Why were these operations done under the lock?
>

I will move these codes outside of the lock.

>> +     spin_unlock_irqrestore(&data->lock, flags);
>> +
>> +     return val;
>> +}
>
>...
>
>> +static void rtd_gpio_irq_handle(struct irq_desc *desc) {
>> +     int (*get_reg_offset)(struct rtd_gpio *gpio, unsigned int offset);
>> +     struct rtd_gpio *data = irq_desc_get_handler_data(desc);
>> +     struct irq_domain *domain = data->gpio_chip.irq.domain;
>> +     struct irq_chip *chip = irq_desc_get_chip(desc);
>> +     unsigned int irq = irq_desc_get_irq(desc);
>> +     int reg_offset;
>> +     u32 status;
>
>> +     int hwirq;
>
>Why signed?
>

I will revised it to unsigned int.

>> +     int i;
>> +     int j;
>> +
>> +     chained_irq_enter(chip, desc);
>
>> +     if (irq == data->irqs[0])
>> +             get_reg_offset = &rtd_gpio_gpa_offset;
>> +     else if (irq == data->irqs[1])
>> +             get_reg_offset = &rtd_gpio_gpda_offset;
>
>Can't it be done before entering into chained IRQ handler?
>

I will revise it.

>> +     for (i = 0; i < data->info->num_gpios; i = i + 31) {
>
>31 ?!  In any case i += 31 is simply shorter.
>

I will revise it.

>> +             reg_offset = get_reg_offset(data, i);
>> +             if (reg_offset < 0)
>> +                     return;
>> +
>> +             status = readl_relaxed(data->irq_base + reg_offset) >> 1;
>> +             writel_relaxed(status << 1, data->irq_base +
>> + reg_offset);
>
>> +             while (status) {
>> +                     j = __ffs(status);
>> +                     status &= ~BIT(j);
>
>NIH for_each_set_bit()
>

I will revise it.

>> +                     hwirq = i + j;
>> +                     if (rtd_gpio_check_ie(data, hwirq)) {
>> +                             int girq = irq_find_mapping(domain,
>hwirq);
>> +                             u32 irq_type =
>> + irq_get_trigger_type(girq);
>> +
>> +                             if ((irq == data->irqs[1]) && ((irq_type &
>IRQ_TYPE_SENSE_MASK) !=
>> +                                     IRQ_TYPE_EDGE_BOTH))
>> +                                     break;
>
>> +                             generic_handle_irq(girq);
>
>Why you can't use generic_handle_domain_irq()?
>

I will revise it.

>> +                     }
>> +             }
>> +     }
>> +
>> +     chained_irq_exit(chip, desc);
>> +}
>
>...
>
>> +     u32 mask = BIT(d->hwirq % 32);
>
>Use proper type and getter for hwirq. It's mentioned in the Documentation.
>

I will use irqd_to_hwirq(d) to get hwirq.

>...
>
>> +static const struct irq_chip rtd_gpio_irq_chip = {
>> +     .name = "rtd-gpio",
>> +     .irq_enable = rtd_gpio_enable_irq,
>> +     .irq_disable = rtd_gpio_disable_irq,
>> +     .irq_set_type = rtd_gpio_irq_set_type,
>
>> +     .flags = IRQCHIP_IMMUTABLE,
>
>Is it? You seems missed something to fulfill the immutability requirements.
>Please consult with the Documentation, it's all written there.
>

I think I missed to call the gpiochip_disable_irq/gpiochip_enable_irq in the
.irq_disable/.irq_enable callback function to inform the gpiolib.
I will revise it.

>> +};
>
>...
>
>> +static const struct of_device_id rtd_gpio_of_matches[] = {
>> +     { .compatible = "realtek,rtd1295-misc-gpio", .data =
>&rtd1295_misc_gpio_info },
>> +     { .compatible = "realtek,rtd1295-iso-gpio", .data =
>&rtd1295_iso_gpio_info },
>> +     { .compatible = "realtek,rtd1395-iso-gpio", .data =
>&rtd1395_iso_gpio_info },
>> +     { .compatible = "realtek,rtd1619-iso-gpio", .data =
>&rtd1619_iso_gpio_info },
>> +     { .compatible = "realtek,rtd1319-iso-gpio", .data =
>&rtd_iso_gpio_info },
>> +     { .compatible = "realtek,rtd1619b-iso-gpio", .data =
>&rtd_iso_gpio_info },
>> +     { .compatible = "realtek,rtd1319d-iso-gpio", .data =
>&rtd_iso_gpio_info },
>> +     { .compatible = "realtek,rtd1315e-iso-gpio", .data =
>> +&rtd_iso_gpio_info },
>
>> +     { },
>
>No comma in the terminator entry.
>

I will revise it.

>> +};
>> +MODULE_DEVICE_TABLE(of, rtd_gpio_of_matches);
>
>Move all these closer to its user (struct platform_device below).
>

I will revise it.

>...
>
>> +     data->gpio_chip.label = dev_name(&pdev->dev);
>
>dev
>
>...
>
>> +     data->gpio_chip.fwnode = dev_fwnode(&pdev->dev);
>
>dev
>
>But why setting parent device is not suffice?
>

I will revise it to data->gpio_chip.parent = dev;.

>...
>
>> +static int rtd_gpio_init(void)
>> +{
>> +     return platform_driver_register(&rtd_gpio_platform_driver);
>> +}
>
>> +
>
>Unneeded blank line.
>

I will remove it.

>> +subsys_initcall(rtd_gpio_init);
>
>Why? Anything that is not on standard initcall must be justified.
>

I will revise it to module_init.

>--
>With Best Regards,
>Andy Shevchenko


Thanks,
Tzuyi Chang