[PATCH v2 02/10] pinctrl: axp209: add pinctrl features

[Quentin Schulz <quentin.schulz@xxxxxxxxxxxxxxxxxx>]

The X-Powers AXP209 has 3 GPIOs. GPIO0/1 can each act either as a GPIO,
an ADC or a LDO regulator. GPIO2 can only act as a GPIO.

This adds the pinctrl features to the driver so GPIO0/1 can be used as
ADC or LDO regulator.

Signed-off-by: Quentin Schulz <quentin.schulz@xxxxxxxxxxxxxxxxxx>
---
 Documentation/devicetree/bindings/pinctrl/pinctrl-axp209.txt |  28 +-
 drivers/pinctrl/pinctrl-axp209.c                             | 462 ++++++-
 2 files changed, 468 insertions(+), 22 deletions(-)

diff --git a/Documentation/devicetree/bindings/pinctrl/pinctrl-axp209.txt b/Documentation/devicetree/bindings/pinctrl/pinctrl-axp209.txt
index a661130..a5bfe87 100644
--- a/Documentation/devicetree/bindings/pinctrl/pinctrl-axp209.txt
+++ b/Documentation/devicetree/bindings/pinctrl/pinctrl-axp209.txt
@@ -1,4 +1,4 @@
-AXP209 GPIO controller
+AXP209 GPIO & pinctrl controller
 
 This driver follows the usual GPIO bindings found in
 Documentation/devicetree/bindings/gpio/gpio.txt
@@ -28,3 +28,29 @@ axp209: pmic@34 {
 		#gpio-cells = <2>;
 	};
 };
+
+The GPIOs can be muxed to other functions and therefore, must be a subnode of
+axp_gpio.
+
+Example:
+
+&axp_gpio {
+	gpio0_adc: gpio0_adc {
+		pin = "GPIO0";
+		function = "adc";
+	};
+};
+
+&example_node {
+	pinctrl-names = "default";
+	pinctrl-0 = <&gpio0_adc>;
+};
+
+GPIOs and their functions
+-------------------------
+
+GPIO	|	Functions
+------------------------
+GPIO0	|	gpio_in, gpio_out, ldo, adc
+GPIO1	|	gpio_in, gpio_out, ldo, adc
+GPIO2	|	gpio_in, gpio_out
diff --git a/drivers/pinctrl/pinctrl-axp209.c b/drivers/pinctrl/pinctrl-axp209.c
index 4a346b7..b35e8dd 100644
--- a/drivers/pinctrl/pinctrl-axp209.c
+++ b/drivers/pinctrl/pinctrl-axp209.c
@@ -1,7 +1,8 @@
 /*
- * AXP20x GPIO driver
+ * AXP20x pinctrl and GPIO driver
  *
  * Copyright (C) 2016 Maxime Ripard <maxime.ripard@xxxxxxxxxxxxxxxxxx>
+ * Copyright (C) 201 Quentin Schulz <quentin.schulz@xxxxxxxxxxxxxxxxxx>
  *
  * This program is free software; you can redistribute it and/or modify it
  * under  the terms of the GNU General  Public License as published by the
@@ -22,14 +23,92 @@
 #include <linux/regmap.h>
 #include <linux/slab.h>
 
+#include <linux/pinctrl/pinctrl.h>
+#include <linux/pinctrl/pinmux.h>
+#include <linux/pinctrl/pinconf-generic.h>
+
 #define AXP20X_GPIO_FUNCTIONS		0x7
 #define AXP20X_GPIO_FUNCTION_OUT_LOW	0
 #define AXP20X_GPIO_FUNCTION_OUT_HIGH	1
 #define AXP20X_GPIO_FUNCTION_INPUT	2
 
+#define AXP20X_PINCTRL_PIN(_pin_num, _pin)			\
+	{							\
+		.number = _pin_num,				\
+		.name = _pin,					\
+	}
+
+#define AXP20X_PIN(_pin, ...)					\
+	{							\
+		.pin = _pin,					\
+		.functions = (struct axp20x_desc_function[]) {	\
+			      __VA_ARGS__, { } },		\
+	}
+
+#define AXP20X_FUNCTION(_val, _name)				\
+	{							\
+		.name = _name,					\
+		.muxval = _val,					\
+	}
+
+struct axp20x_desc_function {
+	const char	*name;
+	u8		muxval;
+};
+
+struct axp20x_desc_pin {
+	struct pinctrl_pin_desc		pin;
+	struct axp20x_desc_function	*functions;
+};
+
+struct axp20x_pinctrl_desc {
+	const struct axp20x_desc_pin	*pins;
+	int				npins;
+};
+
+struct axp20x_pinctrl_group {
+	const char	*name;
+	unsigned long	config;
+	unsigned int	pin;
+};
+
+struct axp20x_pinctrl_function {
+	const char	*name;
+	const char	**groups;
+	unsigned int	ngroups;
+};
+
 struct axp20x_gpio {
 	struct gpio_chip	chip;
 	struct regmap		*regmap;
+	struct pinctrl_dev			*pctl_dev;
+	struct device				*dev;
+	const struct axp20x_pinctrl_desc	*desc;
+	struct axp20x_pinctrl_group		*groups;
+	unsigned int				ngroups;
+	struct axp20x_pinctrl_function		*functions;
+	unsigned int				nfunctions;
+};
+
+static const struct axp20x_desc_pin axp209_pins[] = {
+	AXP20X_PIN(AXP20X_PINCTRL_PIN(0, "GPIO0"),
+		   AXP20X_FUNCTION(0x0, "gpio_out"),
+		   AXP20X_FUNCTION(0x2, "gpio_in"),
+		   AXP20X_FUNCTION(0x3, "ldo"),
+		   AXP20X_FUNCTION(0x4, "adc")),
+	AXP20X_PIN(AXP20X_PINCTRL_PIN(1, "GPIO1"),
+		   AXP20X_FUNCTION(0x0, "gpio_out"),
+		   AXP20X_FUNCTION(0x2, "gpio_in"),
+		   AXP20X_FUNCTION(0x3, "ldo"),
+		   AXP20X_FUNCTION(0x4, "adc")),
+	AXP20X_PIN(AXP20X_PINCTRL_PIN(2, "GPIO2"),
+		   AXP20X_FUNCTION(0x0, "gpio_out"),
+		   AXP20X_FUNCTION(0x2, "gpio_in")),
+};
+
+static const struct axp20x_pinctrl_desc axp20x_pinctrl_data = {
+	.pins	= axp209_pins,
+	.npins	= ARRAY_SIZE(axp209_pins),
 };
 
 static int axp20x_gpio_get_reg(unsigned offset)
@@ -48,16 +127,7 @@ static int axp20x_gpio_get_reg(unsigned offset)
 
 static int axp20x_gpio_input(struct gpio_chip *chip, unsigned offset)
 {
-	struct axp20x_gpio *gpio = gpiochip_get_data(chip);
-	int reg;
-
-	reg = axp20x_gpio_get_reg(offset);
-	if (reg < 0)
-		return reg;
-
-	return regmap_update_bits(gpio->regmap, reg,
-				  AXP20X_GPIO_FUNCTIONS,
-				  AXP20X_GPIO_FUNCTION_INPUT);
+	return pinctrl_gpio_direction_input(chip->base + offset);
 }
 
 static int axp20x_gpio_get(struct gpio_chip *chip, unsigned offset)
@@ -105,30 +175,334 @@ static int axp20x_gpio_get_direction(struct gpio_chip *chip, unsigned offset)
 static int axp20x_gpio_output(struct gpio_chip *chip, unsigned offset,
 			      int value)
 {
+	chip->set(chip, offset, value);
+
+	return 0;
+}
+
+static void axp20x_gpio_set(struct gpio_chip *chip, unsigned offset,
+			    int value)
+{
 	struct axp20x_gpio *gpio = gpiochip_get_data(chip);
 	int reg;
 
 	reg = axp20x_gpio_get_reg(offset);
 	if (reg < 0)
+		return;
+
+	regmap_update_bits(gpio->regmap, reg,
+			   AXP20X_GPIO_FUNCTIONS,
+			   value ? AXP20X_GPIO_FUNCTION_OUT_HIGH :
+			   AXP20X_GPIO_FUNCTION_OUT_LOW);
+}
+
+static int axp20x_pmx_set(struct pinctrl_dev *pctldev, unsigned int offset,
+			  u8 config)
+{
+	struct axp20x_gpio *gpio = pinctrl_dev_get_drvdata(pctldev);
+	int reg;
+
+	reg = axp20x_gpio_get_reg(offset);
+	if (reg < 0)
 		return reg;
 
-	return regmap_update_bits(gpio->regmap, reg,
-				  AXP20X_GPIO_FUNCTIONS,
-				  value ? AXP20X_GPIO_FUNCTION_OUT_HIGH
-				  : AXP20X_GPIO_FUNCTION_OUT_LOW);
+	return regmap_update_bits(gpio->regmap, reg, AXP20X_GPIO_FUNCTIONS,
+				  config);
 }
 
-static void axp20x_gpio_set(struct gpio_chip *chip, unsigned offset,
-			    int value)
+static int axp20x_pmx_func_cnt(struct pinctrl_dev *pctldev)
+{
+	struct axp20x_gpio *gpio = pinctrl_dev_get_drvdata(pctldev);
+
+	return gpio->nfunctions;
+}
+
+static const char *axp20x_pmx_func_name(struct pinctrl_dev *pctldev,
+					unsigned int selector)
 {
-	axp20x_gpio_output(chip, offset, value);
+	struct axp20x_gpio *gpio = pinctrl_dev_get_drvdata(pctldev);
+
+	return gpio->functions[selector].name;
+}
+
+static int axp20x_pmx_func_groups(struct pinctrl_dev *pctldev,
+				  unsigned int selector,
+				  const char * const **groups,
+				  unsigned int *num_groups)
+{
+	struct axp20x_gpio *gpio = pinctrl_dev_get_drvdata(pctldev);
+
+	*groups = gpio->functions[selector].groups;
+	*num_groups = gpio->functions[selector].ngroups;
+
+	return 0;
+}
+
+static struct axp20x_desc_function *
+axp20x_pinctrl_desc_find_func_by_name(struct axp20x_gpio *gpio,
+				      const char *group, const char *func)
+{
+	const struct axp20x_desc_pin *pin;
+	struct axp20x_desc_function *desc_func;
+	int i;
+
+	for (i = 0; i < gpio->desc->npins; i++) {
+		pin = &gpio->desc->pins[i];
+
+		if (!strcmp(pin->pin.name, group)) {
+			desc_func = pin->functions;
+
+			while (desc_func->name) {
+				if (!strcmp(desc_func->name, func))
+					return desc_func;
+				desc_func++;
+			}
+
+			/*
+			 * Pins are uniquely named. Groups are named after one
+			 * pin name. If one pin matches group name but its
+			 * function cannot be found, no other pin will match
+			 * group name.
+			 */
+			return NULL;
+		}
+	}
+
+	return NULL;
+}
+
+static int axp20x_pmx_set_mux(struct pinctrl_dev *pctldev,
+			      unsigned int function, unsigned int group)
+{
+	struct axp20x_gpio *gpio = pinctrl_dev_get_drvdata(pctldev);
+	struct axp20x_pinctrl_group *g = gpio->groups + group;
+	struct axp20x_pinctrl_function *func = gpio->functions + function;
+	struct axp20x_desc_function *desc_func =
+		axp20x_pinctrl_desc_find_func_by_name(gpio, g->name,
+						      func->name);
+	if (!desc_func)
+		return -EINVAL;
+
+	return axp20x_pmx_set(pctldev, g->pin, desc_func->muxval);
+}
+
+static struct axp20x_desc_function *
+axp20x_pctl_desc_find_func_by_pin(struct axp20x_gpio *gpio, unsigned int offset,
+				  const char *func)
+{
+	const struct axp20x_desc_pin *pin;
+	struct axp20x_desc_function *desc_func;
+	int i;
+
+	for (i = 0; i < gpio->desc->npins; i++) {
+		pin = &gpio->desc->pins[i];
+
+		if (pin->pin.number == offset) {
+			desc_func = pin->functions;
+
+			while (desc_func->name) {
+				if (!strcmp(desc_func->name, func))
+					return desc_func;
+
+				desc_func++;
+			}
+		}
+	}
+
+	return NULL;
+}
+
+static int axp20x_pmx_gpio_set_direction(struct pinctrl_dev *pctldev,
+					 struct pinctrl_gpio_range *range,
+					 unsigned int offset, bool input)
+{
+	struct axp20x_gpio *gpio = pinctrl_dev_get_drvdata(pctldev);
+	struct axp20x_desc_function *desc_func;
+	const char *func;
+
+	if (input)
+		func = "gpio_in";
+	else
+		func = "gpio_out";
+
+	desc_func = axp20x_pctl_desc_find_func_by_pin(gpio, offset, func);
+	if (!desc_func)
+		return -EINVAL;
+
+	return axp20x_pmx_set(pctldev, offset, desc_func->muxval);
+}
+
+static const struct pinmux_ops axp20x_pmx_ops = {
+	.get_functions_count	= axp20x_pmx_func_cnt,
+	.get_function_name	= axp20x_pmx_func_name,
+	.get_function_groups	= axp20x_pmx_func_groups,
+	.set_mux		= axp20x_pmx_set_mux,
+	.gpio_set_direction	= axp20x_pmx_gpio_set_direction,
+	.strict			= true,
+};
+
+static int axp20x_groups_cnt(struct pinctrl_dev *pctldev)
+{
+	struct axp20x_gpio *gpio = pinctrl_dev_get_drvdata(pctldev);
+
+	return gpio->ngroups;
+}
+
+static int axp20x_group_pins(struct pinctrl_dev *pctldev, unsigned int selector,
+			     const unsigned int **pins, unsigned int *num_pins)
+{
+	struct axp20x_gpio *gpio = pinctrl_dev_get_drvdata(pctldev);
+	struct axp20x_pinctrl_group *g = gpio->groups + selector;
+
+	*pins = (unsigned int *)&g->pin;
+	*num_pins = 1;
+
+	return 0;
+}
+
+static const char *axp20x_group_name(struct pinctrl_dev *pctldev,
+				     unsigned int selector)
+{
+	struct axp20x_gpio *gpio = pinctrl_dev_get_drvdata(pctldev);
+
+	return gpio->groups[selector].name;
+}
+
+static const struct pinctrl_ops axp20x_pctrl_ops = {
+	.dt_node_to_map		= pinconf_generic_dt_node_to_map_group,
+	.dt_free_map		= pinconf_generic_dt_free_map,
+	.get_groups_count	= axp20x_groups_cnt,
+	.get_group_name		= axp20x_group_name,
+	.get_group_pins		= axp20x_group_pins,
+};
+
+static struct axp20x_pinctrl_function *
+axp20x_pinctrl_function_by_name(struct axp20x_gpio *gpio, const char *name)
+{
+	struct axp20x_pinctrl_function *func = gpio->functions;
+
+	while (func->name) {
+		if (!strcmp(func->name, name))
+			return func;
+		func++;
+	}
+
+	return NULL;
+}
+
+static int axp20x_pinctrl_add_function(struct axp20x_gpio *gpio,
+				       const char *name)
+{
+	struct axp20x_pinctrl_function *func = gpio->functions;
+
+	while (func->name) {
+		if (!strcmp(func->name, name)) {
+			func->ngroups++;
+			return -EEXIST;
+		}
+
+		func++;
+	}
+
+	func->name = name;
+	func->ngroups = 1;
+
+	gpio->nfunctions++;
+
+	return 0;
+}
+
+static int axp20x_attach_group_function(struct platform_device *pdev,
+					const struct axp20x_desc_pin *pin)
+{
+	struct axp20x_gpio *gpio = platform_get_drvdata(pdev);
+	struct axp20x_desc_function *desc_func = pin->functions;
+	struct axp20x_pinctrl_function *func;
+	const char **func_grp;
+
+	while (desc_func->name) {
+		func = axp20x_pinctrl_function_by_name(gpio, desc_func->name);
+		if (!func)
+			return -EINVAL;
+
+		if (!func->groups) {
+			func->groups = devm_kzalloc(&pdev->dev,
+						    func->ngroups * sizeof(const char *),
+						    GFP_KERNEL);
+			if (!func->groups)
+				return -ENOMEM;
+		}
+
+		func_grp = func->groups;
+		while (*func_grp)
+			func_grp++;
+
+		*func_grp = pin->pin.name;
+		desc_func++;
+	}
+
+	return 0;
+}
+
+static int axp20x_build_state(struct platform_device *pdev)
+{
+	struct axp20x_gpio *gpio = platform_get_drvdata(pdev);
+	unsigned int npins = gpio->desc->npins;
+	const struct axp20x_desc_pin *pin;
+	struct axp20x_desc_function *func;
+	int i, ret;
+
+	gpio->ngroups = npins;
+	gpio->groups = devm_kzalloc(&pdev->dev,
+				    gpio->ngroups * sizeof(*gpio->groups),
+				    GFP_KERNEL);
+	if (!gpio->groups)
+		return -ENOMEM;
+
+	for (i = 0; i < npins; i++) {
+		gpio->groups[i].name = gpio->desc->pins[i].pin.name;
+		gpio->groups[i].pin = gpio->desc->pins[i].pin.number;
+	}
+
+	/* We assume 4 functions per pin should be enough as a default max */
+	gpio->functions = devm_kzalloc(&pdev->dev,
+				       npins * 4 * sizeof(*gpio->functions),
+				       GFP_KERNEL);
+	if (!gpio->functions)
+		return -ENOMEM;
+
+	/* Create a list of uniquely named functions */
+	for (i = 0; i < npins; i++) {
+		pin = &gpio->desc->pins[i];
+		func = pin->functions;
+
+		while (func->name) {
+			axp20x_pinctrl_add_function(gpio, func->name);
+			func++;
+		}
+	}
+
+	gpio->functions = krealloc(gpio->functions,
+				   gpio->nfunctions * sizeof(*gpio->functions),
+				   GFP_KERNEL);
+
+	for (i = 0; i < npins; i++) {
+		pin = &gpio->desc->pins[i];
+		ret = axp20x_attach_group_function(pdev, pin);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
 }
 
 static int axp20x_gpio_probe(struct platform_device *pdev)
 {
 	struct axp20x_dev *axp20x = dev_get_drvdata(pdev->dev.parent);
 	struct axp20x_gpio *gpio;
-	int ret;
+	struct pinctrl_desc *pctrl_desc;
+	struct pinctrl_pin_desc *pins;
+	int ret, i;
 
 	if (!of_device_is_available(pdev->dev.of_node))
 		return -ENODEV;
@@ -144,6 +518,8 @@ static int axp20x_gpio_probe(struct platform_device *pdev)
 
 	gpio->chip.base			= -1;
 	gpio->chip.can_sleep		= true;
+	gpio->chip.request		= gpiochip_generic_request;
+	gpio->chip.free			= gpiochip_generic_free;
 	gpio->chip.parent		= &pdev->dev;
 	gpio->chip.label		= dev_name(&pdev->dev);
 	gpio->chip.owner		= THIS_MODULE;
@@ -156,13 +532,56 @@ static int axp20x_gpio_probe(struct platform_device *pdev)
 
 	gpio->regmap = axp20x->regmap;
 
+	gpio->desc = &axp20x_pinctrl_data;
+	gpio->dev = &pdev->dev;
+
+	platform_set_drvdata(pdev, gpio);
+
+	ret = axp20x_build_state(pdev);
+	if (ret)
+		return ret;
+
+	pins = devm_kzalloc(&pdev->dev, gpio->desc->npins * sizeof(*pins),
+			    GFP_KERNEL);
+	if (!pins)
+		return -ENOMEM;
+
+	for (i = 0; i < gpio->desc->npins; i++)
+		pins[i] = gpio->desc->pins[i].pin;
+
+	pctrl_desc = devm_kzalloc(&pdev->dev, sizeof(*pctrl_desc), GFP_KERNEL);
+	if (!pctrl_desc)
+		return -ENOMEM;
+
+	pctrl_desc->name = dev_name(&pdev->dev);
+	pctrl_desc->owner = THIS_MODULE;
+	pctrl_desc->pins = pins;
+	pctrl_desc->npins = gpio->desc->npins;
+	pctrl_desc->pctlops = &axp20x_pctrl_ops;
+	pctrl_desc->pmxops = &axp20x_pmx_ops;
+
+	gpio->pctl_dev = devm_pinctrl_register(&pdev->dev, pctrl_desc, gpio);
+	if (IS_ERR(gpio->pctl_dev)) {
+		dev_err(&pdev->dev, "couldn't register pinctrl driver\n");
+		return PTR_ERR(gpio->pctl_dev);
+	}
+
 	ret = devm_gpiochip_add_data(&pdev->dev, &gpio->chip, gpio);
 	if (ret) {
 		dev_err(&pdev->dev, "Failed to register GPIO chip\n");
 		return ret;
 	}
 
-	dev_info(&pdev->dev, "AXP209 GPIO driver loaded\n");
+	ret = gpiochip_add_pin_range(&gpio->chip, dev_name(&pdev->dev),
+				     gpio->desc->pins->pin.number,
+				     gpio->desc->pins->pin.number,
+				     gpio->desc->npins);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to add pin range\n");
+		return ret;
+	}
+
+	dev_info(&pdev->dev, "AXP209 pinctrl and GPIO driver loaded\n");
 
 	return 0;
 }
@@ -184,5 +603,6 @@ static struct platform_driver axp20x_gpio_driver = {
 module_platform_driver(axp20x_gpio_driver);
 
 MODULE_AUTHOR("Maxime Ripard <maxime.ripard@xxxxxxxxxxxxxxxxxx>");
-MODULE_DESCRIPTION("AXP20x PMIC GPIO driver");
+MODULE_AUTHOR("Quentin Schulz <quentin.schulz@xxxxxxxxxxxxxxxxxx>");
+MODULE_DESCRIPTION("AXP20x PMIC pinctrl and GPIO driver");
 MODULE_LICENSE("GPL");
-- 
git-series 0.9.1
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