[PATCH v3 5/6] pinctrl: Add RTL8231 pin control and GPIO support

[Sander Vanheule <sander@xxxxxxxxxxxxx>]

This driver implements the GPIO and pin muxing features provided by the
RTL8231. The device should be instantiated as an MFD child, where the
parent device has already configured the regmap used for register
access.

Although described in the bindings, pin debouncing and drive strength
selection are currently not implemented. Debouncing is only available
for the six highest GPIOs, and must be emulated when other pins are used
for (button) inputs anyway.

Signed-off-by: Sander Vanheule <sander@xxxxxxxxxxxxx>
---
 drivers/pinctrl/Kconfig           |  11 +
 drivers/pinctrl/Makefile          |   1 +
 drivers/pinctrl/pinctrl-rtl8231.c | 398 ++++++++++++++++++++++++++++++
 3 files changed, 410 insertions(+)
 create mode 100644 drivers/pinctrl/pinctrl-rtl8231.c

diff --git a/drivers/pinctrl/Kconfig b/drivers/pinctrl/Kconfig
index c2c7e7963ed0..e47d6f3550df 100644
--- a/drivers/pinctrl/Kconfig
+++ b/drivers/pinctrl/Kconfig
@@ -221,6 +221,17 @@ config PINCTRL_ROCKCHIP
 	help
           This support pinctrl and gpio driver for Rockchip SoCs.
 
+config PINCTRL_RTL8231
+	tristate "Realtek RTL8231 GPIO expander's pin controller"
+	depends on MFD_RTL8231
+	default MFD_RTL8231
+	select GENERIC_PINCONF
+	select GPIO_REGMAP
+	select PINMUX
+	help
+	  Support for RTL8231 expander's GPIOs and pin controller.
+	  When built as a module, the module will be called pinctrl-rtl8231.
+
 config PINCTRL_SINGLE
 	tristate "One-register-per-pin type device tree based pinctrl driver"
 	depends on OF
diff --git a/drivers/pinctrl/Makefile b/drivers/pinctrl/Makefile
index 5ef5334a797f..239603efb317 100644
--- a/drivers/pinctrl/Makefile
+++ b/drivers/pinctrl/Makefile
@@ -30,6 +30,7 @@ obj-$(CONFIG_PINCTRL_PALMAS)	+= pinctrl-palmas.o
 obj-$(CONFIG_PINCTRL_PIC32)	+= pinctrl-pic32.o
 obj-$(CONFIG_PINCTRL_PISTACHIO)	+= pinctrl-pistachio.o
 obj-$(CONFIG_PINCTRL_ROCKCHIP)	+= pinctrl-rockchip.o
+obj-$(CONFIG_PINCTRL_RTL8231)	+= pinctrl-rtl8231.o
 obj-$(CONFIG_PINCTRL_SINGLE)	+= pinctrl-single.o
 obj-$(CONFIG_PINCTRL_SX150X)	+= pinctrl-sx150x.o
 obj-$(CONFIG_ARCH_TEGRA)	+= tegra/
diff --git a/drivers/pinctrl/pinctrl-rtl8231.c b/drivers/pinctrl/pinctrl-rtl8231.c
new file mode 100644
index 000000000000..d0eea42a4bd3
--- /dev/null
+++ b/drivers/pinctrl/pinctrl-rtl8231.c
@@ -0,0 +1,398 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <linux/bitfield.h>
+#include <linux/gpio/driver.h>
+#include <linux/gpio/regmap.h>
+#include <linux/module.h>
+#include <linux/pinctrl/pinconf-generic.h>
+#include <linux/pinctrl/pinctrl.h>
+#include <linux/pinctrl/pinmux.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+#include <linux/mfd/rtl8231.h>
+
+#define RTL8231_NUM_GPIOS	37
+
+struct rtl8231_function {
+	const char *name;
+	unsigned int ngroups;
+	const char **groups;
+};
+
+struct rtl8231_pin_ctrl {
+	struct pinctrl_desc pctl_desc;
+	unsigned int nfunctions;
+	struct rtl8231_function *functions;
+	struct regmap *map;
+};
+
+/*
+ * Pin controller functionality
+ */
+static const char * const rtl8231_pin_function_names[] = {
+	"gpio",
+	"led",
+	"pwm",
+};
+
+enum rtl8231_pin_function {
+	RTL8231_PIN_FUNCTION_GPIO = BIT(0),
+	RTL8231_PIN_FUNCTION_LED = BIT(1),
+	RTL8231_PIN_FUNCTION_PWM = BIT(2),
+};
+
+struct rtl8231_pin_desc {
+	const enum rtl8231_pin_function functions;
+	const u8 reg;
+	const u8 offset;
+	const u8 gpio_function_value;
+};
+
+#define RTL8231_PIN_DESC(_num, _func, _reg, _fld, _val)		\
+	[_num] = {						\
+		.functions = RTL8231_PIN_FUNCTION_GPIO | _func,	\
+		.reg = _reg,					\
+		.offset = _fld,					\
+		.gpio_function_value = _val,			\
+	}
+#define RTL8231_GPIO_PIN_DESC(_num, _reg, _fld)			\
+	RTL8231_PIN_DESC(_num, 0, _reg, _fld, RTL8231_PIN_MODE_GPIO)
+#define RTL8231_LED_PIN_DESC(_num, _reg, _fld)			\
+	RTL8231_PIN_DESC(_num, RTL8231_PIN_FUNCTION_LED, _reg, _fld, RTL8231_PIN_MODE_GPIO)
+#define RTL8231_PWM_PIN_DESC(_num, _reg, _fld)			\
+	RTL8231_PIN_DESC(_num, RTL8231_PIN_FUNCTION_PWM, _reg, _fld, 0)
+
+/*
+ * All pins have a GPIO/LED mux bit, but the bits for pins 35/36 are read-only. Use this bit
+ * for the GPIO-only pin instead of a placeholder, so the rest of the logic can stay generic.
+ */
+static struct rtl8231_pin_desc rtl8231_pin_data[RTL8231_NUM_GPIOS] = {
+	RTL8231_LED_PIN_DESC(0, RTL8231_REG_PIN_MODE0, 0),
+	RTL8231_LED_PIN_DESC(1, RTL8231_REG_PIN_MODE0, 1),
+	RTL8231_LED_PIN_DESC(2, RTL8231_REG_PIN_MODE0, 2),
+	RTL8231_LED_PIN_DESC(3, RTL8231_REG_PIN_MODE0, 3),
+	RTL8231_LED_PIN_DESC(4, RTL8231_REG_PIN_MODE0, 4),
+	RTL8231_LED_PIN_DESC(5, RTL8231_REG_PIN_MODE0, 5),
+	RTL8231_LED_PIN_DESC(6, RTL8231_REG_PIN_MODE0, 6),
+	RTL8231_LED_PIN_DESC(7, RTL8231_REG_PIN_MODE0, 7),
+	RTL8231_LED_PIN_DESC(8, RTL8231_REG_PIN_MODE0, 8),
+	RTL8231_LED_PIN_DESC(9, RTL8231_REG_PIN_MODE0, 9),
+	RTL8231_LED_PIN_DESC(10, RTL8231_REG_PIN_MODE0, 10),
+	RTL8231_LED_PIN_DESC(11, RTL8231_REG_PIN_MODE0, 11),
+	RTL8231_LED_PIN_DESC(12, RTL8231_REG_PIN_MODE0, 12),
+	RTL8231_LED_PIN_DESC(13, RTL8231_REG_PIN_MODE0, 13),
+	RTL8231_LED_PIN_DESC(14, RTL8231_REG_PIN_MODE0, 14),
+	RTL8231_LED_PIN_DESC(15, RTL8231_REG_PIN_MODE0, 15),
+	RTL8231_LED_PIN_DESC(16, RTL8231_REG_PIN_MODE1, 0),
+	RTL8231_LED_PIN_DESC(17, RTL8231_REG_PIN_MODE1, 1),
+	RTL8231_LED_PIN_DESC(18, RTL8231_REG_PIN_MODE1, 2),
+	RTL8231_LED_PIN_DESC(19, RTL8231_REG_PIN_MODE1, 3),
+	RTL8231_LED_PIN_DESC(20, RTL8231_REG_PIN_MODE1, 4),
+	RTL8231_LED_PIN_DESC(21, RTL8231_REG_PIN_MODE1, 5),
+	RTL8231_LED_PIN_DESC(22, RTL8231_REG_PIN_MODE1, 6),
+	RTL8231_LED_PIN_DESC(23, RTL8231_REG_PIN_MODE1, 7),
+	RTL8231_LED_PIN_DESC(24, RTL8231_REG_PIN_MODE1, 8),
+	RTL8231_LED_PIN_DESC(25, RTL8231_REG_PIN_MODE1, 9),
+	RTL8231_LED_PIN_DESC(26, RTL8231_REG_PIN_MODE1, 10),
+	RTL8231_LED_PIN_DESC(27, RTL8231_REG_PIN_MODE1, 11),
+	RTL8231_LED_PIN_DESC(28, RTL8231_REG_PIN_MODE1, 12),
+	RTL8231_LED_PIN_DESC(29, RTL8231_REG_PIN_MODE1, 13),
+	RTL8231_LED_PIN_DESC(30, RTL8231_REG_PIN_MODE1, 14),
+	RTL8231_LED_PIN_DESC(31, RTL8231_REG_PIN_MODE1, 15),
+	RTL8231_LED_PIN_DESC(32, RTL8231_REG_PIN_HI_CFG, 0),
+	RTL8231_LED_PIN_DESC(33, RTL8231_REG_PIN_HI_CFG, 1),
+	RTL8231_LED_PIN_DESC(34, RTL8231_REG_PIN_HI_CFG, 2),
+	RTL8231_PWM_PIN_DESC(35, RTL8231_REG_FUNC1, 3),
+	RTL8231_GPIO_PIN_DESC(36, RTL8231_REG_PIN_HI_CFG, 4),
+};
+
+#define RTL8231_PIN(_num)				\
+	{						\
+		.number = _num,				\
+		.name = "gpio" #_num,			\
+		.drv_data = &rtl8231_pin_data[_num]	\
+	}
+
+static const struct pinctrl_pin_desc rtl8231_pins[RTL8231_NUM_GPIOS] = {
+	RTL8231_PIN(0),
+	RTL8231_PIN(1),
+	RTL8231_PIN(2),
+	RTL8231_PIN(3),
+	RTL8231_PIN(4),
+	RTL8231_PIN(5),
+	RTL8231_PIN(6),
+	RTL8231_PIN(7),
+	RTL8231_PIN(8),
+	RTL8231_PIN(9),
+	RTL8231_PIN(10),
+	RTL8231_PIN(11),
+	RTL8231_PIN(12),
+	RTL8231_PIN(13),
+	RTL8231_PIN(14),
+	RTL8231_PIN(15),
+	RTL8231_PIN(16),
+	RTL8231_PIN(17),
+	RTL8231_PIN(18),
+	RTL8231_PIN(19),
+	RTL8231_PIN(20),
+	RTL8231_PIN(21),
+	RTL8231_PIN(22),
+	RTL8231_PIN(23),
+	RTL8231_PIN(24),
+	RTL8231_PIN(25),
+	RTL8231_PIN(26),
+	RTL8231_PIN(27),
+	RTL8231_PIN(28),
+	RTL8231_PIN(29),
+	RTL8231_PIN(30),
+	RTL8231_PIN(31),
+	RTL8231_PIN(32),
+	RTL8231_PIN(33),
+	RTL8231_PIN(34),
+	RTL8231_PIN(35),
+	RTL8231_PIN(36),
+};
+
+static int rtl8231_get_groups_count(struct pinctrl_dev *pctldev)
+{
+	return ARRAY_SIZE(rtl8231_pins);
+}
+
+static const char *rtl8231_get_group_name(struct pinctrl_dev *pctldev, unsigned int selector)
+{
+	return rtl8231_pins[selector].name;
+}
+
+static int rtl8231_get_group_pins(struct pinctrl_dev *pctldev, unsigned int selector,
+	const unsigned int **pins, unsigned int *num_pins)
+{
+	if (selector >= ARRAY_SIZE(rtl8231_pins))
+		return -EINVAL;
+
+	*pins = &rtl8231_pins[selector].number;
+	*num_pins = 1;
+
+	return 0;
+}
+
+static const struct pinctrl_ops rtl8231_pinctrl_ops = {
+	.get_groups_count = rtl8231_get_groups_count,
+	.get_group_name = rtl8231_get_group_name,
+	.get_group_pins = rtl8231_get_group_pins,
+	.dt_node_to_map = pinconf_generic_dt_node_to_map_all,
+	.dt_free_map = pinconf_generic_dt_free_map,
+};
+
+static int rtl8231_get_functions_count(struct pinctrl_dev *pctldev)
+{
+	struct rtl8231_pin_ctrl *ctrl = pinctrl_dev_get_drvdata(pctldev);
+
+	return ctrl->nfunctions;
+}
+
+static const char *rtl8231_get_function_name(struct pinctrl_dev *pctldev, unsigned int selector)
+{
+	struct rtl8231_pin_ctrl *ctrl = pinctrl_dev_get_drvdata(pctldev);
+
+	return ctrl->functions[selector].name;
+}
+
+static int rtl8231_get_function_groups(struct pinctrl_dev *pctldev, unsigned int selector,
+	const char * const **groups, unsigned int *num_groups)
+{
+	struct rtl8231_pin_ctrl *ctrl = pinctrl_dev_get_drvdata(pctldev);
+
+	*groups = ctrl->functions[selector].groups;
+	*num_groups = ctrl->functions[selector].ngroups;
+
+	return 0;
+}
+
+static int rtl8231_set_mux(struct pinctrl_dev *pctldev, unsigned int func_selector,
+	unsigned int group_selector)
+{
+	const struct rtl8231_pin_desc *desc =
+		(struct rtl8231_pin_desc *) &rtl8231_pins[group_selector].drv_data;
+	struct rtl8231_pin_ctrl *ctrl = pinctrl_dev_get_drvdata(pctldev);
+	unsigned int func_flag = BIT(func_selector);
+	unsigned int function_mask;
+	unsigned int gpio_function;
+
+	if (!(desc->functions & func_flag))
+		return -EINVAL;
+
+	function_mask = BIT(desc->offset);
+	gpio_function = desc->gpio_function_value << desc->offset;
+
+	if (func_flag == RTL8231_PIN_FUNCTION_GPIO)
+		return regmap_update_bits(ctrl->map, desc->reg, function_mask, gpio_function);
+	else
+		return regmap_update_bits(ctrl->map, desc->reg, function_mask, ~gpio_function);
+}
+
+static int rtl8231_gpio_request_enable(struct pinctrl_dev *pctldev,
+	struct pinctrl_gpio_range *range, unsigned int offset)
+{
+	struct rtl8231_pin_desc *desc =
+		(struct rtl8231_pin_desc *) &rtl8231_pins[offset].drv_data;
+	struct rtl8231_pin_ctrl *ctrl = pinctrl_dev_get_drvdata(pctldev);
+	unsigned int function_mask;
+	unsigned int gpio_function;
+
+	function_mask = BIT(desc->offset);
+	gpio_function = desc->gpio_function_value << desc->offset;
+
+	return regmap_update_bits(ctrl->map, desc->reg, function_mask, gpio_function);
+}
+
+static const struct pinmux_ops rtl8231_pinmux_ops = {
+	.set_mux = rtl8231_set_mux,
+	.get_functions_count = rtl8231_get_functions_count,
+	.get_function_name = rtl8231_get_function_name,
+	.get_function_groups = rtl8231_get_function_groups,
+	.gpio_request_enable = rtl8231_gpio_request_enable,
+	.strict = true,
+};
+
+static int rtl8231_pinctrl_init_functions(struct device *dev, struct rtl8231_pin_ctrl *ctrl)
+{
+	struct rtl8231_function *function;
+	const char **group_name;
+	unsigned int f_idx;
+	unsigned int pin;
+
+	ctrl->nfunctions = ARRAY_SIZE(rtl8231_pin_function_names);
+	ctrl->functions = devm_kcalloc(dev, ctrl->nfunctions, sizeof(*ctrl->functions), GFP_KERNEL);
+	if (!ctrl->functions) {
+		dev_err(dev, "failed to allocate pin function descriptors\n");
+		return -ENOMEM;
+	}
+
+	for (f_idx = 0; f_idx < ctrl->nfunctions; f_idx++) {
+		function = &ctrl->functions[f_idx];
+		function->name = rtl8231_pin_function_names[f_idx];
+
+		for (pin = 0; pin < ctrl->pctl_desc.npins; pin++)
+			if (rtl8231_pin_data[pin].functions & BIT(f_idx))
+				function->ngroups++;
+
+		function->groups = devm_kcalloc(dev, function->ngroups,
+			sizeof(*function->groups), GFP_KERNEL);
+		if (!function->groups)
+			return -ENOMEM;
+
+		group_name = function->groups;
+		for (pin = 0; pin < ctrl->pctl_desc.npins; pin++)
+			if (rtl8231_pin_data[pin].functions & BIT(f_idx))
+				*group_name++ = rtl8231_pins[pin].name;
+	}
+
+	return 0;
+}
+
+static int rtl8231_pinctrl_init(struct device *dev, struct rtl8231_pin_ctrl *ctrl)
+{
+	struct pinctrl_dev *pctl;
+	int err;
+
+	ctrl->pctl_desc.name = "rtl8231-pinctrl";
+	ctrl->pctl_desc.owner = THIS_MODULE;
+	ctrl->pctl_desc.pctlops = &rtl8231_pinctrl_ops;
+	ctrl->pctl_desc.pmxops = &rtl8231_pinmux_ops;
+	ctrl->pctl_desc.npins = ARRAY_SIZE(rtl8231_pins);
+	ctrl->pctl_desc.pins = rtl8231_pins;
+
+	err = rtl8231_pinctrl_init_functions(dev, ctrl);
+	if (err)
+		return err;
+
+	err = devm_pinctrl_register_and_init(dev->parent, &ctrl->pctl_desc, ctrl, &pctl);
+	if (err) {
+		dev_err(dev, "failed to register pin controller\n");
+		return err;
+	}
+
+	err = pinctrl_enable(pctl);
+	if (err)
+		dev_err(dev, "failed to enable pin controller\n");
+
+	return err;
+}
+
+/*
+ * GPIO controller functionality
+ */
+static int rtl8231_gpio_reg_mask_xlate(struct gpio_regmap *gpio, unsigned int base,
+	unsigned int offset, unsigned int *reg, unsigned int *mask)
+{
+	unsigned int pin_mask = BIT(offset % RTL8231_BITS_VAL);
+
+	if (base == RTL8231_REG_GPIO_DATA0 || offset < 32) {
+		*reg = base + offset / RTL8231_BITS_VAL;
+		*mask = pin_mask;
+	} else if (base == RTL8231_REG_GPIO_DIR0) {
+		*reg = RTL8231_REG_PIN_HI_CFG;
+		*mask = FIELD_PREP(RTL8231_PIN_HI_CFG_DIR_MASK, pin_mask);
+	} else {
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int rtl8231_pinctrl_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct rtl8231_pin_ctrl *ctrl;
+	struct gpio_regmap_config gpio_cfg = {};
+	struct gpio_regmap *gr;
+	int err;
+
+	ctrl = devm_kzalloc(dev, sizeof(*ctrl), GFP_KERNEL);
+	if (!ctrl)
+		return -ENOMEM;
+
+	ctrl->map = dev_get_regmap(dev->parent, NULL);
+	if (!ctrl->map)
+		return -ENODEV;
+
+	if (IS_ERR(ctrl->map))
+		return PTR_ERR(ctrl->map);
+
+	err = rtl8231_pinctrl_init(dev, ctrl);
+	if (err)
+		return err;
+
+	gpio_cfg.regmap = ctrl->map;
+	gpio_cfg.parent = dev->parent;
+	gpio_cfg.ngpio = RTL8231_NUM_GPIOS;
+	gpio_cfg.ngpio_per_reg = RTL8231_BITS_VAL;
+
+	gpio_cfg.reg_dat_base = GPIO_REGMAP_ADDR(RTL8231_REG_GPIO_DATA0);
+	gpio_cfg.reg_set_base = GPIO_REGMAP_ADDR(RTL8231_REG_GPIO_DATA0);
+	gpio_cfg.reg_dir_in_base = GPIO_REGMAP_ADDR(RTL8231_REG_GPIO_DIR0);
+	gpio_cfg.quirks = GPIO_REGMAP_QUIRK_SET_DIRECTION_FIRST;
+
+	gpio_cfg.reg_mask_xlate = rtl8231_gpio_reg_mask_xlate;
+
+	gr = devm_gpio_regmap_register(dev, &gpio_cfg);
+	if (IS_ERR(gr)) {
+		dev_err(dev, "failed to register gpio controller\n");
+		return PTR_ERR(gr);
+	}
+
+	return 0;
+}
+
+static struct platform_driver rtl8231_pinctrl_driver = {
+	.driver = {
+		.name = "rtl8231-pinctrl",
+	},
+	.probe = rtl8231_pinctrl_probe,
+};
+module_platform_driver(rtl8231_pinctrl_driver);
+
+MODULE_AUTHOR("Sander Vanheule <sander@xxxxxxxxxxxxx>");
+MODULE_DESCRIPTION("Realtek RTL8231 pin control and GPIO support");
+MODULE_LICENSE("GPL v2");
-- 
2.31.1